Vehicle safety.The safety of the vehicle includes a complex of constructive and operational properties that reduce the likelihood of road accidents, the severity of their consequences and a negative impact on environment.
The concept of the safety of the design of the car includes active and passive safety.
Active security Designs are constructive measures aimed at preventing accidents. These include measures that ensure controllability and resistance when driving, efficient and reliable braking, light and reliable steering, low driver fatigue, good visibility, effective action of external lighting and signaling devices, as well as an increase in the dynamic quality of the car.
Passive security Constructions are constructive events that exclude or minimize the consequences of the accident for the driver, passengers and cargo. They provide for the use of trauma-safe steering structures, energy-intensive elements on the front and back of the car, soft cabin and body upholstery and soft linings, safety belts, self-skiast glasses, airtight fuel system, reliable fire fighting devices, locks for the hood and body with blocking devices, safe Layout parts and all cars.
In recent years, great attention is paid to improving the safety of car design in all countries producing them. In the United States of America more widely. Under the active safety of the vehicle means its properties that reduce the likelihood of a road accident.
Active safety is provided by several operational properties that allow the driver to confidently control the car, accelerate and brake with the necessary intensity, make maneuvering on the roadway, which requires a road situation, without significant expenditures of physical forces. The main of these properties: traction, brake, stability, handling, permeability, informativeness, habitability.
Under passive vehicle safetyunderstanding the properties that reduce the severity of the traffic accident.
Distinguish the external and internal passive car safety. The main requirement of external passive security is to ensure such a constructive implementation of the outer surfaces and elements of the car, in which the likelihood of human damage by these elements in the case of a road accident would be minimal.
As is known, a significant number of incidents are associated with clashes and departures on a still obstacle. In this regard, one of the requirements for external passive safety of cars is the protection of drivers and passengers from injuries, as well as the car itself from damage using external structural elements.
Figure 8.1 - Scheme of forces and moments acting on a car
Figure 8.1 - Vehicle safety structure
An example of an element of passive safety may be an injury bumper, the purpose of which is to mitigate the blows of the car on the obstacles at low speed speeds (for example, when maneuvering in the parking area).
The endurance limit for man is 50-60g (G-acceleration of free fall). The endurance limit for an unprotected body is the energy value perceived directly by the body corresponding to the speed of movement of about 15 km / h. At 50 km / h, the energy exceeds the permissible approximately 10 times. Therefore, the task is to reduce the acceleration of the human body when a collision due to long deformations of the front part of the body of the car, which would absorb as much energy as possible.
That is, the more the deformation of the car and the longer it happens, the less the driver is experiencing when a collision with an obstacle.
Decorative body elements, knobs, mirrors and other parts attached to the car body are relevant to external passive safety. On modern cars, tired door handles are increasingly used, non-pedestrian injuries in the case of a traffic accident. The protruding emblems of manufacturers on the front of the car do not apply.
Two basic requirements are presented to the internal passive safety of the car:
Creating conditions under which a person could safely withstand any overload;
Exclusion of traumatic elements inside the body (cab). The driver and passengers in a collision after the instant stop of the car still continue to move, keeping the speed of movement that the car had before a collision. It is at this time that there is a majority of injuries as a result of hitting heads about windshield, breasts about the steering wheel and the steering column, the knees of the lower edge of the instrument panel.
An analysis of road accidents shows that the overwhelming majority of the dead were in the front seat. Therefore, when developing passive security measures, first of all, attention is paid to ensuring the safety of the driver and passenger in the front seat.
The design and rigidity of the car body is performed so that the front and rear parts of the body are deformed during collisions, and the interior deformation (cabin) was as minimal to preserve the life support zone, that is, the minimally necessary space, within which the squeezing of the human body is excluded inside the body .
In addition, the following measures should be provided, which reduces the severity after a collision:
The need to move the steering and steering column and the absorption of the impact energy, as well as the uniform distribution of the blow on the surface of the driver's chest;
Exception of emissions or loss of passengers and driver (reliability of door locks);
The presence of individual protective and holding means for all passengers and driver (seat belts, head restraints, pneumatic oil);
Lack of traumatic elements in front of passengers and driver;
Body equipment by injuries security glasses. The effectiveness of the use of seat belts in combination with other activities is confirmed by statistical data. Thus, the use of belts reduces the number of injuries by 60 - 75% and reduces their severity.
One of the effective ways to solve the problem of restricting the movement of the driver and passengers in a collision is the use of pneumatic pillows, which when a car collide with an obstacle is filled with compressed gas for 0.03 - 0.04C, perceive the driver and passengers and thereby reduce the severity of injury.
Under the afternoon safety of the vehicleit is understood by his properties in the event of an accident not to prevent the evacuation of people, not to inflict injury during evacuation and after it. The main measures of postavary security are fire fighting activities, measures to evacuate people, alarm.
The most severe consequence of the road accident is the fire of the car. Most often, ignition occurs at severe incidents, such as a collision of cars, races for fixed obstacles, as well as tilting. Despite the slight probability of fire (0.03 -1.2% of the total incident), their consequences are hard.
They cause almost complete destruction of the car and with the impossibility of evacuation - the death of people, in such incidents, the fuel is poured out of the damaged tank or from the filler neck. Flooding comes from the hot parts of the exhaust gas release system, from the sparks with a faulty ignition system or the body parts that occurred from friction on the road or about the body of another car. There may be other reasons for fire.
Under the environmental safety of the vehicleit is understood by his property to reduce the degree of negative environmental impact. Environmental safety covers all parties to the car. Below are the main aspects of ecology associated with the operation of the car.
Loss of the useful area of \u200b\u200bthe Earth. The land necessary for the movement and parking lots is excluded from the use of other sectors of the national economy. The overall length of the world network road roads The solid coating exceeds 10 million km, which means the loss of area over 30 million hectares. The expansion of streets and squares leads to "an increase in the territories of cities and the elongation of all communications. In cities with a developed road network and auto-service enterprises, settled for movement and parking lots, take up to 70% of the total area.
In addition, huge territories occupy plants for the production and repair of cars, the services of ensuring the functioning of road transport: gas station, one hundred, campgrounds, etc.
Air pollution. The bulk of harmful impurities scattered in the atmosphere is the result of car operation. The medium power engine throws into the atmosphere in one day of operation of about 10 m 3 of exhaust gases, which include carbon monoxide, hydrocarbons, nitrogen oxides and many other toxic substances.
In our country, the following norms of the average daily maximum permissible concentrations of toxic substances in the atmosphere are established:
Hydrocarbons - 0.0015 g / m;
Carbon monoxide - 0.0010 g / m;
Nitrogen dioxide - 0.00004 g / m.
Using natural resources.Millions of tons of high-quality materials are used to produce and operate vehicles, which leads to the depletion of their natural reserves. With the exponential increase in the power consumption per capita, characteristic of industrially developed sts, will soon come a moment when existing energy sources will not be able to satisfy the needs of a person.
A significant proportion of energy consumed is spent by cars, kp. The engines of which are 0.3 0.35, therefore, 65 - 70% of the energy potential is not used.
Noise and vibration.The noise level, a long-term tolerant person without harmful consequences, amount to 80 - 90 dB on the streets of large cities and industrial centers The noise level reaches 120-10 dB. The soil fluctuations caused by the movement of cars are adversely affected by buildings and structures. To protect a person from a detrimental effect of vehicle noise, various techniques are used: improving the design of cars, noise protection structures and green areas along the lively urban highways, the organization of such a movement mode when the noise level is the smallest.
The value of traction force is the greater, the greater the engine torque and gear ratios of the gearbox and the main transmission. But the amount of traction force can not exceed the force of the clutch of the leading wheels with the road. If the load force exceeds the clutch force with the road, then the drive wheels will slip.
Clutch powerequal to the product of the clutch coefficient on the coupling weight. For the traction car, the coupling weight is equal to the normal load percentage of the wheels.
Clutch coefficientdepends on the type and state of the coating of the road, from the design and state of the tires (air pressure, tread pattern), from the load and speed of the vehicle. The magnitude of the clutch coefficient is reduced at wet and wet surfaces of the road, especially with an increase in the speed of movement and the worn tire protector. For example, with a dry road with an asphalt concrete coating, the clutch coefficient is 0.7 - 0.8, and for wet - 0.35 - 0.45. Under the icing road, the clutch coefficient is reduced to 0.1 - 0.2.
Gravitythe car is attached in the center of gravity. Modern passenger cars, the center of gravity is located at an altitude of 0.45 - 0.6 m from the surface of the road and approximately in the middle of the car. Therefore, the normal load of the passenger car is distributed on its axes approximately equally, i.e. Coupling weight is 50% of the normal load.
The height of the center of gravity from trucks 0.65 - 1 m. In fully loaded cargo vehicles of the coupling weight is 60,75% of the normal load. In all-wheel drive cars, the coupling weight is equal to the normal load of the car.
When the car moves, the specified ratios are changed, since there is a longitudinal redistribution of the normal load between the axles of cars when transmitting the leading wheels are larger than the leading wheels, and when braking a car - front wheels. In addition, the redistribution of the normal load between the front and rear wheels takes place when the car is moving to the descent or lift.
Redistribution of the load, changing the magnitude of the coupling weight, affects the magnitude of the clutch of the wheels with the road, the brake properties and stability of the car.
Resistance forces movement. Tracting force on the drive wheels of the car. With a uniform movement of the car along the horizontal road, the forces are: the strength of resistance to rolling and the power of air resistance. When the car moves, the resistance force arises for the rise (Fig. 8.2), and during the acceleration of the car - the force of resistance to overclocking (inertia strength).
The power of resistance to rollingarises due to the deformation of the tires and the surface of the road. It is equal to the product of the normal load of the car on the coefficient of rolling resistance.
Figure 8.2 - Scheme of forces and moments acting on a car
The coefficient of rolling resistance depends on the type and state of the coating of the road, the construction of the tires, their wear and air pressure in them, the velocity of the vehicle. For example, for a road with an asphalt concrete coating, a rolling resistance coefficient is 0.014 0.020, for a dry ground road - 0.025-0.035.
On solid road surfaces, the rolling resistance coefficient increases sharply with a decrease in the air pressure in tires, and increases with an increase in the speed of movement, as well as with increasing brake and torque.
The power of air resistance depends on the air resistance coefficient, the frontal area and the velocity of the car. The coefficient of air resistance is determined by the type of car and the form of its body, and the frontal area is the wheel rings (the distance between the tire centers) and the car height. Air resistance strength increases in proportion to the square of the velocity of the car.
Resistance strength risemoreover, the greater the mass of the car and the steepness of the lifting of the road, which is estimated by the angle of lifting in degrees or the magnitude of the slope, expressed as a percentage. When the car is moving under the slope, the resistance force rise, on the contrary, speeds up the movement of the car.
On the roads with asphalt concrete coating, a longitudinal slope usually does not exceed 6%. The coefficient of resistance to rolling to take equal to 0.02, then the overall resistance of the road will be 8% tons of normal vehicle load.
The power of resistance overclocking(Inertia's strength) depends on the mass of the car, its acceleration (speed increase per unit time) and the mass of rotating parts (flywheel, wheels), to accelerate which also expects the thrust force.
When the car is accelerated, the resistance force acceleration is directed towards, inverse movement. When driving a car and slowing down its movement, the power of inertia is directed towards the movement of the car.
Brake car.Brake dynamic is characterized by the car's ability to quickly reduce speed and stop. A reliable and efficient brake system allows the driver to confidently lead the car at high speed and, if necessary, stop it in a short portion of the path.
Modern cars have four brake systems: working, replacement, parking and auxiliary. Moreover, the drive to all the contours of the brake system is separate. The most important for managing and security is a working brake system. With its help, a service and emergency braking of the car is carried out.
Service is called braking with a slight slowdown (1-3 m / s 2). It is used to stop the car at the previously intended place or for a smooth reduction in speed.
Emergency call braking with a large slowdown, usually the maximum, reaching up to 8 m / s2. It is used in a dangerous atmosphere to prevent an obstacle unexpectedly.
When braking the car on and about the wheel, there is no force of thrust, but the brake forces of PT1 and RT2, as shown on (Fig. 8.3). The power of inertia in this case is directed towards the movement of the car.
Consider the process emergency braking. The driver noticing the obstacle, assesses the road situation, decides on braking and transfers the leg to the brake pedal. Time T, necessary for these actions (driver reaction time), depicted on (Fig. 8.3) by the segment of AV.
Car during this time passes the path S without reducing speed. The driver then presses the brake pedal and pressure from the main brake cylinder (or brake crane) is transmitted by wheel brakes (the time of operation of the brake drive TPT - segment Sun. TT time depends mainly on the design of the brake drive. It is equal to average 0.2-0.4C in hydraulic drive vehicles and 0,6-0 , 8 seconds with pneumatic. In auto trays with a pneumatic brake-driven, TT time can reach 2-3 s. The car during TT runs the ST path, but not reducing speed.
Figure 8.3 - stopping and braking car
After time, the TRT brake system is fully turned on (point C), and the vehicle speed begins to decline. At the same time, the slowdown increases first (CD segment, the time of increasing the braking force TNT), and then remains approximately constant (installed) and equal to the JUST (TIV TIV, segment DE).
The duration of the TNT period depends on the mass of the vehicle, the type and state of the road surface. The greater the mass of the car and the tire clutch coefficient with the road, the more time t. The value of this time is in the range of 0.1-0.6 s. During the TNT, the car moves to the SNT distance, and its speed is somewhat reduced.
When driving with the installed slowdown (time Town, segment DE), the vehicle speed over each second decreases on the same value. At the end of the braking, it drops to zero (point E), and the car, having passed the path of Suste, stops. The driver removes his leg from the brake pedal and turns out-braking (the taking place to top, the EF section).
However, under the action of the power of inertia, the front axle is loaded during braking, and the rear, on the contrary, is unloaded. Therefore, the reaction on the front wheels RZL is increasing, and the rear RZ2 decreases. Accordingly, the clutch forces are changed, so most cars have full and simultaneous use of clutch by all wheels of the car, it is extremely rare and the actual slowdown is less than the maximum possible.
To take into account the decline in deceleration, the formula for determining the Justa has to introduce a correction coefficient of braking efficiency K.E, equal to 1.1-1.15 for passenger cars and 1.3-1.5 for trucks and buses. On slippery roads, brake forces on all wheels of the car almost simultaneously reach the clutch force values.
The brake path is less than stopping, because During the driver's reaction, the car moves to a considerable distance. The stopping and brake path increases with increasing speed and decrease in the clutch coefficient. Minimal valid values brake path At the initial speed of 40 km / h on a horizontal road with dry, clean and smooth coating are normalized.
The efficiency of the brake system is largely depends on its technical status and technical status of tires. In the case of penetration into the brake system of oil or water, the friction coefficient between brake linings and drums (or discs) is reduced, and the braking torque decreases. When wear tire protector, the clutch coefficient decreases.
This entails a decrease in brake forces. In operation, the brake forces of the left and right wheels of the car are different, which causes its rotation around the vertical axis. The reasons may be a variable wear of brake linings and drums or tires or penetration into the brake system of one side of the car oil or water, which reduce the friction coefficient and reduce the braking torque.
Car stability.Under stability understand the properties of the car to resist the drift, slip, tipping. Distinguish the longitudinal and transverse stability of the car. Loss of transverse stability is more likely.
Currency stability of the car is called its property to move in the right direction without corrective effects from the driver, i.e. With the steering wheel constant. The car with bad course stability all the time unexpectedly changes the direction of movement.
This creates a threat to other vehicles and pedestrians. The driver, driving an unstable car, is forced to especially closely monitor the road situation and constantly adjust the movement to prevent departure beyond the road. With long-term control, the driver is quickly tired, the possibility of an accident increases.
The violation of the course stability occurs as a result of the action of the disturbing forces, for example, impulse of the side wind, the drives of the wheels on the irregularities of the road, and also due to the sharp turn of the driven by the driver. Sustainability loss can also be caused by technical malfunctions (incorrect adjustment of brake mechanisms, excessive backlash in the steering or swissing, puncture of the tire, etc.)
Especially dangerous loss of courseworthy at high speed. The car by changing the direction of movement and dismissed even to a small angle, it may be in a short time to be on the counter movement. So, if a car moving at a speed of 80 km / h will deviate from the rectilinear direction of the movement for only 5 °, then after 2,5s it moves to the side almost the I M and the driver may not have time to return the car to the old band.
Figure 8.4 - Scheme of forces acting on the car
Often the car loses stability when driving along the road with a transverse slope (oblique) and when turning on the horizontal road.
If the car moves along the Kosoyrato (Fig.8.4, a) gravity G is with the surface of the road angle β and it can be decomposed into two components: the force of P1, a parallel road, and the force of P2 perpendicular to it.
Power P1, strive to move the car under the slope and tilting it. The greater the angle of Kosoyra β, the greater the power P1, therefore, the most likely the loss of transverse stability. When the car turn is the cause of the loss of stability, the centrifugal power of the RC is (Fig. 8.4, b), directed from the center of rotation and applied to the center of gravity of the car. It is directly proportional to the square of the velocity of the car and is inversely proportional to the radius of the curvature of its trajectory.
The transverse slip of tires on the way counteract the clutch forces, as already noted above, which depend on the clutch coefficient. On dry, clean coatings of the clutch strength are large enough, and the car does not lose stability even with a large transverse force. If the road is covered with a layer of mock mud or ice, the car can be incorporated even when it moves at low speed on a relatively color curve.
The maximum speed with which you can move along the curvilinear area with a radius R without transverse glide of tires is equal to that, performing a rotation on a dry asphalt concrete coating (Jx \u003d 0.7) at R \u003d 50m, you can move at a speed of about 66 km / h. Overcoming the same turn after the rain (jx \u003d 0.3) without slip can only be moved at a speed of 40-43 km / h. Therefore, before turning, you need to reduce the speed, the greater the less the radius of the upcoming turn. The formula defines the speed at which the wheels of both car bridges slide in the transverse direction at the same time.
Such a phenomenon in practice is extremely rare. Much more often begins to slide the tires of one of the bridges - front or rear. The transverse slide of the front axle rarely occurs and besides quickly stops. Most slide the wheels of the rear axle, which, starting to move in the transverse direction, slide faster. Such an accelerating transverse glide is called a drift. To quench the start-up, you need to turn the steering wheel towards the drift. The car will start moving along a stronger curve, the rotation radius will increase, and the centrifugal force will decrease. Turn the steering wheel is needed smoothly and quickly, but not on a very big angle so as not to cause a turn in the opposite direction.
As soon as the drive stop, you also need to smoothly and quickly return the steering wheel into a neutral position. It should also be noted that, to exit the rear-wheel drive car, the fuel supply must be reduced, and on the front-wheel drive, on the contrary, to increase. Often, skid occurs during emergency braking when the tire clutch with an expensive is already used to create brake forces. In this case, it is necessary to immediately stop or weaken the braking and thereby increase the transverse stability of the car.
Under the action of the transverse force, the car can not only slide on the road, on and tipped onto the side or on the roof. The ability to overturn depends on the position of the center, the severity of the car. The higher the center of gravity, the most likely overturning. Buses, as well as trucks engaged in transportation of lightweight, bulk cargo (hay, straw, empty packaging, etc.) and liquids are especially narrowing. Under the action of the transverse power of the springs on one side of the car, it is shred and the body bends it, increasing the risk of tipping.
Car handling.Under the handling understand the property of the car to ensure movement in the direction specified by the driver. Car handling more than other operational properties is associated with the driver.
To ensure good manageability, the design parameters of the car must comply with the psychophysiological characteristics of the driver.
Car handling is characterized by several indicators. The main of them: the limit value of the curvature of the trajectory with circular motion of the car, the limit value of the rate of change of the curvature of the trajectory, the amount of energy spent on the control of the car, the magnitude of the spontaneous deviations of the car from the specified direction of movement.
Controlled wheels under the influence of the road irregularities are constantly deviated from the neutral position. The ability of controlled wheels to maintain a neutral position and return to it after rotation is called stabilization of controlled wheels. Weight stabilization is provided by the transverse slope of the poverty front suspension. When turning the wheels, thanks to the cross-tilt, the car is lifted, but with its weight to strive to return the rotated wheels at its original position.
The speed stabilizing moment is due to longitudinal inclination pivot. Shkvelen is located so that its upper end is directed back, and the bottom ahead. The axis of the kkvorna crosses the surface of the road ahead of the wheel contact spot with an expensive. Therefore, when driving a car, the power of resistance to rolling creates a stabilizing moment regarding the axis of the pivot. With a good steering wheel drive and the steering mechanism, after turning the car, the controlled wheels and the steering wheel should return to the neutral position without the driver's participation.
In the steering mechanism, the worm is located relative to the roller with a small overcast. In this regard, in the middle position, the gap between the worm and the roller is minimal and close to zero, and when the roller and the bumps are deviated to any side, the gap increases. Therefore, with the neutral position of the wheels in the steering mechanism, increased friction is created, promoting stabilization of wheels and high-speed stabilizing moments.
Incorrect adjustment of the steering mechanism, large gaps in the steering wheel can cause bad stabilization of controlled wheels, the cause of the vibration of the vehicle. The car with poor stabilization of controlled wheels spontaneously changes the direction of movement, as a result of which the driver is forced to continuously rotate the steering wheel then in one, then in the other side to return the car to his movement strip.
Poor stabilization of controlled wheels requires significant costs of the physical and mental energy of the driver, increases wear of tires and parts of the steering drive.
When the car is moving on the rotation, the outer and internal wheels are rolling around the circles of various radius (Fig. 8.4). In order for the wheels rolling without slip, their axes should intersect at one point. L To perform this condition, controlled wheels should be rotated at different angles. Turning the wheels of the car at different angles provides steering trapezium. The outer wheel always turns to a smaller angle than the inner, and this difference is the greater the greater the angle of rotation of the wheels.
The elasticity of tire has a significant effect on the rotation of the car. Under action on the side of the lateral force (no matter, inertia or lateral winds), the tires are deformed and the wheels along with the car are shifted towards the operation of the lateral force. This displacement is the greater, the more lateral force and the higher the elasticity of the tires. The angle between the wheel rotation plane and the direction of its movement is called an angle of the injection 8 (Fig. 8.5).
With the same angles of the front and rear wheelhings, the car retains the specified direction of movement, but rotate relative to it by the angle of the angle. If the angle of the wheel of the front axle is larger than the angle of the wheel of the rear trolley, then when driving a car on a turn, it will strive to move along a larger arcle than the one that the driver sets. This property of the car is called insufficient turning.
If the angle of the rear axle wheel is larger than the angle of the wheel of the front axle, then when driving a car on a turn, it will strive to move along the arc of a smaller radius than the one as the driver sets. This property of the car is called excess turning.
Turning the car can be somewhat controlled by applying tires of different plasticity by changing the pressure in them by changing the distribution of the mass of the car along the axes (by placing the cargo).
Figure 8.5 - Kinematics of car turning and wheel injection diagram
The car with excess turning is more maneuverable, but requires more attention and high professional skill from the driver. The car with insufficient turning requires less attention and skill, but makes it difficult to work the driver, as it requires turns of the steering wheel to large corners.
The effect of rotation and the movement of the car becomes noticeable and essential only at high speeds.
The controllability of the car depends on the technical condition of its chassis and steering. Reducing the pressure in one of the tires increases its rolling resistance and reduces the transverse rigidity. Therefore, the car with a slosted tire is constantly deviating and its side. To compensate for this, the driver turns controlled wheels to the side opposite to the opposite, and the wheels begin to roll with a side slide, intensively wear out at the same time.
Wearing parts of the steering actuator and a pivot compound leads to the formation of gaps and the occurrence of arbitrary oscillations of the wheels.
With large gaps and high speed of movement, the fluctuations of the front wheels can be so significant that their grip will be disturbed. The cause of wheel fluctuations can be their imbalance due to the bus imbalance, patchball packerel, dirt on the wheel disk. To prevent wheel oscillations, they must be balanced on a special stand by installing balancing loads.
Car permeability.Under the passability, they understand the property of the car to move on uneven and difficult terrain, not hurt behind the irregularities of the lower body outline. The car's passability is characterized by two groups of indicators: geometric indicators of passability and supporting indicators of patency. Geometric indicators characterize the likelihood of the car behind the irregularities, and the disconnection is characterized by the possibility of movement in difficult areas of roads and off-road.
On the passability, all cars can be divided into three groups:
General-purpose cars ( wheel formula 4x2, 6x4);
High-pass vehicles (wheel formula 4x4, 6x6);
High passability cars having a special layout and construction, multiple with all the driving wheels, caterpillar or semi-barrier, amphibian cars and other cars, specially designed for work only in off-road conditions.
Consider geometric patency. Road clearance is the distance between the lowest point of the car and the surface of the road. This indicator characterizes the possibility of moving the car without hiding for obstacles located on the way of movement (Fig. 8.6).
Figure 8.6 - Geometric Pentility Indicators
Radius of longitudinal and transverse patency are radii of circles tangent to wheels and the lowest point of the car located inside the base (gauge). These radii characterize the height and outlines of the obstacle that can overcome the car, not hurt for it. What they are less, the higher the ability of the car to overcome significant irregularities without hiding behind them with their lower points.
The front and bottom corners of the sink, respectively, αP1 and αP2, are formed by the surface of the road and the plane, tangent to the front or rear wheels and to the protruding lower points of the front or back of the car.
The maximum height of the threshold, which can overcome the car, for the slave wheels is 0.35 ... 0.65 radius of the wheel. The maximum height of the threshold overcome the leading wheel can reach the radius of the wheel and is sometimes limited to the non-traction capabilities of the car or the coupling properties of the road, but by small values \u200b\u200bof the angles of the sweep or lumen.
The maximum necessary width of the passage with the minimum rotation radius of the car characterizes the possibility of maneuvering on small sites, so the cargo of the car in the horizontal plane is often considered as a separate operational property maneuverability. The most maneuverable are cars with all controlled wheels. In the case of towing a trailer or semi-trailers, the car maneuverability deteriorates, since the Mary turns of the trailer mixes the trailer to the center of the turn, which is why the width of the travelery movement is larger than a single car.
The resulting trap indicators include the following. The maximum strength of the thrust is the greatest force that is capable of developing a low-transmission car. Coupling Weight - the strength of the gravity of the car, coming on the drive wheels. The more scene scenes, the higher the car's passability.
Among the cars with the wheel formula 4X2, the highest passability of the rear-wheel drive and front-wheel drive cars have the greatest loss, since with such a layout, the drive wheels are always loaded with a mass of the engine. The specific tire pressure on the support surface is defined as the ratio of the vertical load on the bus to the contact area, measured along the contour of the tire contact spots with a road Q \u003d GF.
This indicator is of great importance for car traffic. The smaller the specific pressure, the less the soil is destroyed, the depth of the rut to be formed, less resistance to rolling and above the car's passability.
The coefficient of the track is the ratio of the gauge of the front wheels to the rings of the rear wheels. With the full match of the front and rear wheel assets, the rear rolling on the ground, compacted by the front wheels, and the rolling resistance is minimally. If the front and rear tracks are miserably, additional energy is spent on the destruction by the rear wheels of the compacted walls of the track formed by the front wheels. Therefore, there are often single tires for high-pass vehicles, single tires are installed on the rear wheels, thereby reducing the rolling resistance.
The car's passability largely depends on its design. For example, in high-pass industries, elevated friction differentials are used, blocked inter-axis and inter-wheeled differentials, wide-profile tires with developed primers, winchs for self-drawing and other devices that facilitate the car's passability in off-road conditions.
The informativeness of the car.Informative understand the property of the car to provide the necessary information of the driver and other participants in the movement. In any conditions, the driver perceived by the driver is essential for securely controlled by car. In case of insufficient visibility, especially at night, the informativeness among other operating properties of the car has a special effect on traffic safety.
Distinguish internal and external informativeness.
Internal informative - This is the property of the car to provide the driver information about the work of aggregates and mechanisms. It depends on the design of the instrument panel, devices that provide visibility, handles, pedals and car control buttons.
The location of the instruments on the panel and their device should allow the driver to spend the minimum time to monitor the instrument testimony. Pedals, handles, buttons and control keys must be located so that the driver finds them easily, especially at night.
The visibility depends mainly on the size of windows and windshield wipers, widths and location of the cabins of the cabin, the design of glass ware, the system of blowing and heating of glass, the location and design of the rear-view mirrors. The visibility also depends on the convenience of the seat.
External informative - This is the property of the car to inform other participants in the movement on their position on the road and the intentions of the driver to change the direction and speed of movement. It depends on the size, forms and painting of the body, the location of the light railings, the external light alarm, the beep.
Trucks of medium and large lifting capacity, road train, buses thanks to their dimensions are more noticeable and better distinguishable than passenger cars and motorcycles. Cars painted in dark colors (black, gray, green, blue), due to the difficulty of their distinction, 2 times more often fall into an accident than painted in bright and bright colors.
The external light signaling system should be distinguished by the reliability of work and ensure the unique interpretation of signals by road users in any visibility conditions. Lights of Middle and Far Light, as well as others additional headlights (Spotlight, fog) improve the inner and external car informativeness when driving at night and in conditions of insufficient visibility.
The inhabitability of the car.The inhabitability of the vehicle is the properties of the surrounding driver and passengers of the environment, which determine the level of comfort and aesthetic I and the place of their work and rest. The inhabitability is characterized by a microclimate, ergonomic characteristics of the cabin, noise and vibrations, gas and smoothness.
The microclimate is characterized by a combination of temperature, humidity and air velocity. The optimal temperature of the air in the cab is considered 18 ... 24 ° C. A decrease or increase in temperature, especially for a long period of time, affects the psycho-physiological characteristics of the driver, leads to a slowdown) of the reaction and mental activity, to physical fatigue and, as a result, to a decrease in labor productivity and traffic safety.
The humidity and speed of air largely affect the thermoregulation of the body. With low temperature and high humidity, heat transfer and the body is exposed to more intensive cooling. At high temperature and humidity of the heat transfer sharply decreases, which leads to overheating the body.
The driver begins to feel the movement of air in the cockpit at its speed 0.25 m / s. The optimal speed of air movement in the cockpit is about 1m / s.
Ergonomic properties characterize the correspondence of the seat and vehicle controls by anthropometric human parameters, i.e. sizes of his body and limbs.
The design of the seat should contribute to the landing of the driver behind the controls providing minimum energy costs and constant readiness for a long time.
The color gamut inside the cabin also has a certain attention on the driver's psyche, which, naturally, affects the performance of the driver and traffic safety.
The nature of noise and vibrations is the same - mechanical oscillations of parts of the car. Sources of noise in the car are engine, transmission, exhaust gas production system, suspension. The action of noise on the driver is the cause of an increase in its reaction time, temporary deterioration of the characteristics of the vision, reduce attention, violation of the coordination of movements and functions of the vestibular apparatus.
Domestic and international regulatory documents establish the maximum permissible level of noise in the cockpit within 80 to 85 dB.
Unlike the noise perceived by the ear, vibrations are perceived by the surface of the driver's body. Just like noise, vibration is harmful to the driver's condition, and with constant exposure during a long time it may affect its health.
Zagaznost is characterized by the concentration of exhaust gases, fuel vapor and other harmful impurities in the air. A special danger to the driver represents carbon monoxide - gas without color and smell. Finding into the blood of a person through the lungs, he deprives her ability to deliver oxygen cells of the body. A person dies from choking, without feeling and not understanding what happens to him.
In this regard, the driver must closely monitor the tightness of the exhaust engine, prevent suction of gases and vapors from motor compartment In the cab. It is strictly forbidden to let and the main thing to warm the engine in the garage when people are in it.
In the arsenal of the active safety of the car there are many anti-emergency systems. Among them are old systems and new-fashioned inventions.
Anti-lock brake system (ABS), Traction Control, Electronic Stability Control (ESC), night vision system and automatic cruise control - these fashion technologies that help the driver on the road today.
However, some accidents occur, despite the level of driver's skills of participants. Large accidents with fatal outcomes occurring from time to time around the world, confirm that safety cannot remain on the deposit of luck, but should be seriously taken into account.
Tires are the most important element of the safety of a modern car. Think: they are the only thing that connects the car with the road. A good tire set gives a great advantage in how the car reacts to emergency maneuvers. The quality of tires also changes significantly on machines. Sport tires Have a better clutch with an expensive, but their softer structure is quickly destroyed and they serve much less.
Anti-lock brake system (ABS) is a often underestimated and misunderstood element of the active safety of the car. ABS helps to stop faster and not lose control of the car, especially on slippery surfaces.
In the event of an emergency stop, ABS operates in a different way than ordinary brakes. With conventional brakes, a sudden stop often leads to blocking wheels, which causes a skid. Anti-lock brake system determines when the wheel is blocked and releases it, controlling the brakes 10 times faster than the driver can do.
When ABS is triggered, a characteristic sound is distributed and the vibration on the brake pedal is felt. To effectively use ABS, change braking technique. You do not need to let and press the brake pedal again, as it turns off the ABS system. In case of emergency braking, you should press the pedal once and gently hold it until the car is stopped.
Summing up, it can be said that the anti-lock brake system eliminates the need to press and release the brake pedal in the event of an emergency stop or braking on wet or slippery surfaces.
Traction Control is a valuable option that improves braking and stability when turning on a slippery road using a combination of electronics, transmission control and ABS.
Some systems automatically reduce the engine speed and include brakes on certain wheels when pressed on gas and braking. BMW, Cadillac, and Mercedes-Benz and many other manufacturers offer new system Stabilization control on high and medium price level models. Such a system helps stabilize the car when it begins to leave under control. Such systems are increasingly appearing on less expensive brands and auto models.
ABS or ABS with tracs (wheel slip control system), STC (stability and wheel control system) or DSTC (system of dynamic stability and wheelchair control system) is not all offered on the market. We describe all systems and evaluate and useful for the active safety of the car.
Active security
What is the active safety of the car?
Speaking scientific language - this is a combination of the design and operational properties of a car aimed at preventing road traffic accidents and the exclusion of the prerequisites for their occurrence associated with constructive features car.
And if it is easier to speak, then these are the systems of the car that help to prevent accidents.
Below is more about the parameters and systems of the car, affecting its active safety.
1. Understanding
The reliability of nodes, aggregates and car systems is the defining factor of active safety. Especially high demands are made to the reliability of elements related to maneuver - brake system, steering, suspension, engine, transmission, and so on. The increase in reliability is achieved by improving the design, the use of new technologies and materials.
2. Car layout
Car layout is three types:
a) front-engine-layout of a car, at which the engine is located in front of the passenger compartment. It is the most common and has two options: rear-wheel drive (class) and front-wheel drive. The last kind of lineup - front-door front-wheel drive - received currently widespread due to a number of advantages over the drive to the rear wheels:
Better stability and manageability when driving at high speed, especially on wet and slippery road;
Providing a non-ovable weight load on the drive wheels;
A smaller noise level, which contributes to the absence of a cardan shaft.
At the same time, front-wheel drive cars have a number of shortcomings:
With full load, overclocking overclocking and wet road;
At the time of braking, too uneven weight distribution between the axes (on the wheels of the front axle accounts for 70% -75% of the weight of the car) and accordingly the brake forces (see braking properties);
Tires of the front leading controlled wheels are loaded more respectively, more susceptible to wear;
Drive on the pre-wheel wheels requires the use of complex narrow - hinges of equal angular velocities (shrusov)
Combining the power unit (engine and gearbox) with the main transmission complicates access to individual elements.
b) Layout with central engine location - the engine is between the front and rear axles, for passenger cars is quite rare. It allows you to get the most spacious salon With specified dimensions and good distribution over the axes.
c) Request - Engine is located behind the passenger compartment. Such a layout was widespread on small cars. When the torque is transmitted to the rear wheels, it made it possible to obtain an inexpensive power unit and the distribution of such a load on the axes, at which about 60% of the weight accounted for the rear wheels. It has a positive effect on the car's passability, but negatively on its stability and controllability, especially at high speeds. Cars with this layout currently are practically not produced.
3. Brake properties
The possibility of preventing an accident is most often associated with intensive braking, so it is necessary that the braking properties of the car ensure its effective slowdown in any road situations.
To perform this condition, the strength developed by the brake mechanism should not exceed the clutch forces with an expensive dependent on the weight load on the wheel and the state of the road surface. Otherwise, the wheel will be blocked (no longer rotate) and start sliding, which can lead (especially when blocking multiple wheels) to the car drift and a significant increase in the braking path. To prevent blocking, forces developing by brake mechanisms, should be proportional to the weight load on the wheel. This is implemented using more efficient disc brakes.
On modern cars, an anti-lock system (ABS) is used, adjusting the power of braking of each wheel and preventing their slip.
In winter and summer, the condition of the road surface is different, therefore, for the best implementation of the braking properties it is necessary to use tires corresponding to the season.
Read more about brake systems \u003e\u003e
4. Traction properties
Traction properties (traction dynamics) of the vehicle determine its ability to intensively increase the speed of movement. From these properties, the driver has largely dependent on overtaking, the passage of interrons. Especially important, the traction speaker has to exit emergency situations where it is too late for it, maneuvering does not allow complex conditions, and you can avoid an accident, only ahead of events.
As well as in the case of brake forces, the force of thrust on the wheel should not be more clutch forces with the road, otherwise it will begin to slip. Prevents this anti-test system (PBS). When the car is accelerated, it slows down the wheel whose rotation speed is greater than that of the rest, and if necessary, reduces the power developed by the engine.
5. Car stability
Sustainability - the ability of the car to maintain a movement along a given trajectory, counteracting the forces that suspend its skid and tipping in various road conditions at high speeds.
Distinguish the following types of stability:
Transverse with rectilinear movement (term stability).
Her violation is manifested in digging (changing the direction of movement) of the car on the road and can be caused by the action of the lateral strength of the wind, different values \u200b\u200bof traction or braking forces on the wheels of the left or right side, they are dried or sliding. large backlash in the steering control, irregular angles of wheel installation, etc.;
Criminated with curved motion.
Its violation leads to drift or lumps under the action of centrifugal force. Especially worsens the sustainability increase in the position of the center of the mass of the car (for example, a large mass of cargo on a removable roof trunk);
Longitudinal.
Its violation is manifested in the bucking of the leading wheels when overcoming protracted iced or snow-covered lifts and a car climbing back. This is especially characteristic of road trains.
6. Car handling
Controllability - the ability of the car to move in the direction specified by the driver.
One of the characteristics of the controllability is turning - the car property change the direction of movement with a fixed steering wheel. Depending on the change in the radius of rotation under the influence of lateral forces (centrifugal force on the turn, wind strength, etc.) turning can be:
Insufficient - the car increases the rotation radius;
Neutral - the rotation radius does not change;
Excessive - rotation radius decreases.
Distinguish tire and roll turning.
Tire turning
Tire turning is associated with the property of tires to move at an angle to a given direction with a lateral input (shift of the contact spot with a road relative to the wheel rotation plane). When installing the tires of another model, the turning can change the car on turns when driving at a high speed will behave differently. In addition, the magnitude of the side voltage depends on the tire pressure, which must comply with the operating instructions for the car.
Roll turning
Renovane turning is due to the fact that when the body slope (roll), the wheels change their position relative to the road and the car (depending on the type of suspension). For example, if the pendant pendant, the wheels bend on the side of the roll, increasing the railway.
7. Informativeness
Informativeness - property of the car to provide the necessary information of the driver and other participants in the movement. Insufficient information from other vehicles located on the road, on the state of the road surface, etc. Often becomes the cause of the accident. The informativeness of the car is divided into inner, external and extra.
Internal provides the ability to reproduce the information needed to manage the car.
It depends on the following factors:
The visibility should allow the driver in a timely manner and without interference to obtain all the necessary information about the traffic situation. Faulty or inefficiently operating washers, a system of blowing and heating of glasses, wiper, the lack of standard rear-view mirrors deteriorate the visibility under certain road conditions.
Relocation of the instrument panel, buttons and control keys, speed switching lever, etc. It should provide the driver to the minimum time for control covers, influences on switches, etc.
External informativeness - ensuring other participants in the motion of information from the car, which is necessary for proper interaction with them. It includes a system of external light alarm, beep, sizes, shape and painting of the body. The informativeness of passenger cars depends on the contrast of their color relative to the road surface. According to statistics, cars painted black, green, gray and blue colors, two times more often in the accident due to the difficulty of distinguishing them in conditions of insufficient visibility and at night. Faulty turn signs, stop signals, overall lights will not allow other participants in the road on time to recognize the driver's intentions and take the right decision.
Additional informativeness - the property of the car, allowing it to exploit it in conditions of limited visibility: at night, in the fog, etc. It depends on the characteristics of the lighting system devices and other devices (for example, fog headlights) that improve the perception by the driver's information about the road transportation.
8. Comfortability
The comfort of the car determines the time during which the driver is able to drive a car without fatigue. An increase in comfort contributes to the use of ACCP, speed regulators (cruise control), etc. Currently produced cars equipped with adaptive cruise control. It not only automatically maintains speed at a given level, but, if necessary, reduces it up to the complete stop of the car.
Active safety car
The active safety of the car depends not only from the maneuverability and skills of the driver, but also from many other factors. To begin with, it should be sorted out than active safety differs from passive. The passive safety of the car is responsible for ensuring that the passengers and the driver are not injured after the accident, and active safety helps to avoid collisions.
For this, many systems have been developed, each of which has its meaning to maintain a car safe. First of all, we are not talking about any specialized means, but about the working condition of all systems of the car as a whole. The car must be reliable, and this is that its mechanisms cannot unexpectedly refuse. A sudden breakdown that is not related to a collision or other external damage becomes the cause of accidents much more often than it would be possible to think.
The brakes play a special role in this case. Ability to stop the car saved the life and health to many. Of course, in winter or during the rain, the brakes can be powerless, if you bring a grip with the surface of the road, in this case the wheel will stop rotating and split from it. In order for this not to be important to change tires on the season, it is especially significant during the ice rate.
For the active security of the car, the car is actually a car assembly. It is in mind where the engine is located: in front of the passenger compartment (front-door), between the axes of the car (centralotone, it is infrequent) and, finally, the engine is located behind the passenger compartment (rear-engine). The last assembly method is the most unreliable, so lately it is almost not found.
The most reliable type of assembly, in which the engine is located in front of the salon, and at the same time the car front-wheel drive. This increases the resistance of the car, and, it means, and its safety on the road. Of course, he has its own minuses, including a more serious tire load, which have to change more often, but it is still often secondary meaning.
The ability to quickly change the speed, accelerating and slowing down, is also not in the last place. Especially the traction dynamics are important in the conditions of overtaking and the passage of dangerous intersections. Together with the handling of the car (thanks to which the car rides in the direction you need) the traction dynamics creates car maneuverability.
And finally, to avoid the accident, the driver must have a good review and be able to predict and avoid an accident. And it depends on the health of the instrument panel, as well as mirrors, headlights, etc. The security system does not have anything unavailable, remember it.
Active safety car
The active safety of the car, in contrast to passive, is aimed primarily for the alarm of the accident. To protect the car from collision on the track, these systems affect the suspension, steering, brakes. The use of an anti-blocking system (ABS) has become a real breakthrough in this area.
The anti-locking system is currently applied on many cars both foreign and domestic production. The role of ABS in the active safety of the car is difficult to overestimate, since it is this system that prevents the wheel lock at the time of braking, which gives the driver the opportunity in a difficult situation on the road not to lose control of the car.
In the early 1990s, Bosch was made another step towards automotive security. She developed and implemented the electronic movement stabilization system (ESP). The first car that was equipped with this device became Mercedes S 600.
Nowadays, this system has become a mandatory part of the configuration of cars that pass the Euroncap series crash tests, and this decision was not in vain. ESP is exactly what prevents the car driving and keeps it on a safe trajectory of movement, as well as supplements its work of the ABS anti-lock system, controls the operation of the transmission and the engine, monitors the acceleration of the car and rotating the steering wheel.
An important part of the active safety of the machine is car tireswho are obliged to show not only the high performance of comfort and patency, but also a reliable clutch with an expensive on a wet road and ice. The largest step in the development of tire products is the production in the 1970s of the last century of the first winter tires.
They differed from the usual the fact that the materials used in the production of such rubber were adapted to the effects of low temperatures, and the tire pattern provided optimally reliable adhesion with snow-covered and iced expensive.
The need for continuous development of automotive security systems has led to the creation of new technologies in the field of the majority of world automakers cooperate in this area. The quality of safety on the roads is designed at times, to increase the functional currently developed now, which can combine cars of various brands into a single information network.
Using GPS technology, cars will be able to exchange information about the situation on the road, to inform each other their speed and the trajectory of movement, thereby preventing clashes and emergencies. Also, independent experts noted that in recent years there have been truly progressive security systems.
So, for example, toyota company Motors has developed a system that is located in the car and controls the driver's condition. If the system is detected using sensors that the driver is distracted, it became scattered and even began to fall asleep behind the wheel, then a warning is triggered that actually wakes up the driver.
If we look into the future of automotive security, we will make an interesting conclusion: the car will become friendly to passengers and pedestrians. Such a view lead modern Japanese concepts. Honda has already presented its futuristic car PUYO.
Its body is made of soft materials produced based on silicone. Thus, even if there is a hit on a pedestrian, then the damage will be like from a collision with another person on the sidewalk, it will remain just apologize and disperse. We hope that safety in the near future will increase not only on foreign cars, but also on our with you, domestic developments - "Viburnum" and "Priors".
Active safety car
The essence of the active safety of the car lies in the lack of sudden failures in the design systems of the car, especially related to the possibility of maneuver, as well as the driver's capabilities confidently and comfortably control the mechanical system of the car road.
1. Basic requirements for systems
The active safety of the car also includes the correspondence of the traction and braking dynamics of the car by road conditions and transport situations, as well as the psycho-physiological features of drivers:
a) the magnitude of the stopping path depends on the brake dynamics of the car, which should be the smallest. In addition, the brake system must allow the driver to very flexibly choose the necessary intensity of braking;
b) The driver's confidence during overtaking, the passage of intersections and the intersection of highways depends on the traction dynamics of the car. Of particular importance is the car dynamics of the car to get out of emergency situations, when it is too late to slow down, and the maneuver cannot be done in terms due to cramped conditions. In this case, it is necessary to discharge the situation only by ahead of events. 2. Sustainability and car handling:
a) stability - this is the ability to resist the drift and tipping in various road conditions and at high speeds of movement;
b) controllability is the operating property of the car, allowing the driver to drive a car at the lowest costs of mental and physical energy, when maneuvers in terms of maintaining or referring to the direction of movement;
c) maneuverability or quality of a car, characterized by the value of the smallest radius of rotation and dimensions of the car;
d) stabilization - the ability of the elements of the system of the car-driver-road to resist the unstable movement of the car or the ability of the specified system itself or with the help of the driver to maintain the optimal positions of the natural axes of the car during movement;
e) the brake system, to ensure the reliability of which separate drives on the front and rear wheels are taken, automatic control of gaps in the system to ensure a stable response time, blocking devices for preventing driving when braking, etc.;
e) steering must provide permanent reliable communication With a steering wheel and a tire contact zone with an expensive with a slight muscular driver's effort.
The steering should be reliable in operation, from the point of view of a sudden refusal, as well as to have significant reserves for abrasion (wear) of the main parts of the steering mechanism nodes;
g) the sudden refusal of the car from the preservation of the direction of movement asked by the driver can also be caused by the incorrect installation of the car control wheels, which often causes difficulties in critical situations;
h) Reliable tires significantly increase the safety of car traffic and allow you to move the car with a proper power circuit in the contact zone with the road;
and) the reliability of signaling systems and lighting. Failure to one of the systems and ignorance about this driver of a maneuvering car can lead to a lack of understanding of the development of the transport situation by other drivers, which reduces the active safety of the complex as a whole.
3. Optimal conditions for visual observation road conditions and situations:
a) visibility;
b) visibility;
c) the visibility of the surface of the road and other items in the light of headlights;
d) wrapping and heating windows (windshield, rear and side).
4. Conditions for the driver:
a) noise insulation;
b) microclimate;
c) the convenience of seats and use by other controls;
d) lack of harmful vibrations.
5. Concept and standardized location and action of controls in all types of vehicles:
a) location;
b) efforts on management bodies equal to all types of cars, etc.;
c) coloring;
d) identical blocking and unlocking methods. home
Man and car
Driver's perception
Attention
Thinking and memory
Emotions and Will of Man driving
Driving skills
Mastery driving a car
Professional selection of drivers
Speed
The tempo of the driver
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Control car in the dark
Selection of tactics of motion at night
Slippery road
Bus stops
Treatment of drivers
Driver's workplace
Microclimate Salon
Hygiene clothing and shoes
Harmful impurities
WARNING OF ELILATED PEASURE PEASURE
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Driver's power mode
Sport and Driver's Profession
Alcohol and road injury
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vOLVO cars are driving - the result of many years of special development in the field of road safety and an integrated approach to its provision.
Safe ride - This means that even in the most unexpected situations you fully rely on your car. The car is obliged to obey the slightest team of the driver and do it quickly, efficiently and reliable.
The Volvo car must be steadily manageable, respond quickly and predictably on the driver's actions and be easy to manage. In order to achieve this, Volvo engineers organized an "intellectual" interaction of all dynamic car body and chassis systems, and the same serve a hard, resistant twisting body and ergonomic driver's seat.
The basis of safe management is the sustainable behavior of the car, regardless of the road situation or the state of the road surface. Any Volvo car is designed to maintain the trajectory of motion even under the most adverse conditions, such as:
Sharp acceleration, both at the direct section and when turning turning
Sharp turns or maneuvers in order to avoid collision
Sudden side gusts of wind at bridges, in tunnels or when driving with heavy trucks
In achieving the sustainability of behavior on the road in the design of the car, many elements play a role. So the body has a lattice design consisting of longitudinal and transverse metal sections. The components of the external panels are pressed into larger sections to avoid unnecessary seams. The glasses of all deaf windows are glued to the body with superproof polyurethane glue.
On models of V - V70 and Cross Country - frame, framing the opening of the rear door, is additionally enhanced in order to impart the stiffness of the elongated roof section. The stability of these models to twist is 50% higher than their predecessors.
Screw resistance Volvo S80 is 60% higher than that of an earlier model S70, and at least 90% higher compared to Volvo S60.
The construction of the body excludes unwanted movements and gives the body an exceptional resistance to twisting forces. This in turn contributes to ensuring a stable, easily controlled car behavior on the road. Body resistance to twisting forces is of particular importance with sharp movements to the side or with strong side winds.
A considerable role in the resistance of the car plays the role of competently designed suspension. The front suspension has in the design of the spring rack type MC Person, in which each of the front wheels is supported by a spring with a transversely located low link. The slope of the spring rack (and the location of the lower mount relative to the axial line of the wheel) provides negative shoulder Officon, contributing to high course stability, for example, when overclocking or on an uneven surface. The suspension geometry is carefully balanced to eliminate the impact of undesirable forces when changing the direction of movement and maintain a sense of car handling during acceleration.
Detailed description:
When the direction of movement changes, the wheel turns relative to the middle axis of the spring rack.
The distance between the axial lines of the wheel and the spring rack forms a lever
This lever should be as short as possible to avoid unwanted phenomena when changing the direction of movement.
The suspension geometry, in addition, contributes to the rapid and accurate answer of the car on the steering action. The angle of installation and the length of the spring rack also ensure the moderation of changes in the angle of the wheel setting relative to the road surface when the position of the suspension changes. This contributes to a reliable clutch of tires with an expensive.
The rear suspension has control of the wheel installation.
Previous models of Volvo, such as 240 and 740, were equipped with rear-wheel drive - the presenter was the rear axle. The main advantages of such a design were to provide a permanent width of the rut and the angle of plating the wheels relative to the roadbed even with a significant suspension during the suspension. Thus, the maximum clutch of the wheels with the road was ensured. Disadvantage rear drive And the heavy differential was their significant weight, which limited the comfort of the car in motion, as well as who made it prone to "jumping" on the irregularities of the road (the phenomenon known as a large unsophisticated mass).
Modern Volvo cars (with the exception of Volvo C70) are equipped with an independent rear suspension with a system (rear axle MULTILINK). The presence of intermediate thrust provides the minimum possible change in the angle of the wheel installation when the suspension moves. In addition, the suspension is relatively easy (low unsresprising weight), so that the system provides both a high level of comfort and reliable grip of the wheels with the road. Thrust controlling the longitudinal direction of the wheel provide a specific infringement effect. When turning turns, the rear wheels are slightly rotated in the same direction as the front wheels, providing car stability and instantaneous response to steering steering, as well as its stable and predictable behavior. The system counteracts the rear axle demolition. In addition, this system also contributes to a braking course stability. Volvo C70 is equipped with a semi-independent rear suspension, known as Deltalink. Such a design also limits the change in the angle of the wheels in the movement of the suspension and provides a small infringement when turning turns.
volvo cars can be equipped with automatically self-leveling suspension. In such a system, shock absorbers are used, the rigidity of which is automatically adjustable depending on the weight of the car. When you attach a trailer or lead a heavy loaded car, this system supports the body in a position parallel to the roadway. Thus, it is possible to maintain the controllability parameters unchanged and reduce the risk of blinding the drivers of the oncoming machines.
To increase the reliability, all Volvo models are equipped with a rush steering mechanism - it is minimized to a minimum of moving parts, and is beneficial from others with a small weight. The system provides a quick car response to steering steering, high accuracy and allows you to feel good way, thus increasing driving safety.
All tires for Volvo cars are manufactured according to the original VOLVO specifications. Tire profile and tread pattern determine the quality of the clutch of the wheel with the roadpapers. Wide low-profile tires with a narrow and small protector provide excellent adhesion with a dry coating. A higher and narrow profile with a wide and deep tread is more suitable for wet, covered with slush and snow of roads. Low sidewalls low-profile tires must be extremely durable to avoid the risk of damage to peak pressure generated by the movements of the suspension. In addition, such a tire design provides stability on turns. The disadvantage of the low and rigid sidewall of the tire is its limited flexibility that rides less comfortable. Alloy wheels reduce the unsappressible mass of the car with respect to heavier steel wheels. Light wheels react faster on the irregularities of the roadway, improving the grip with uneven road coating. Various models of Volvo are equipped with tires and wheels, the most appropriate challenges of the controllability and comfort of the car and the extremely rigid requirements of Volvo to driving safety.
In the design of Volvo cars, the maximum possible uniformity of the load distribution on the wheels between the front and rear suspension. This contributes to the safe, sustainable behavior of the car on the road. For example, the weight of Volvo S60 is distributed as follows: 57% on the front suspension and 43% - to the back.
To ensure stability, reliable and predictable behavior on winding roads last models Volvo - S80, V70, Cross Country and S60 are distinguished by very broad rings and a large distance from the front to the rear axle, or the wheelbase.
But sustainable behavior on the road is achieved not only by a competently designed suspension. Technical solutions in Volvo car transmission also allow you to feel confident when moving. One solution is the wheel drive of equal length.
Modern models of Volvo are equipped with transversely arranged engines, leading the front wheels in motion. However, such a configuration creates one problem. Since the power take-off point is located on the side of the longitudinal axis of the car, the distance from it to each of the leading wheels is unequal. With different length of the drives of the driving wheels and, taking into account the elasticity of the drive material, it creates the risk of the so-called "torque on the steering wheel" with a sharp acceleration with a simultaneous turn of the steering wheel, when the feeling of the "disobedient" steering wheel is created. However, Volvo managed to reduce this problem to a minimum: we achieved the power of the power to be on the longitudinal axis of the car, applying intermediate shafts for this. Thus, the front-wheel drive Volvo remains well-controlled and in such a situation.
For safe driving in winter, the automatic transmission is equipped with the "winter" mode (W). This feature provides an improved clutch with a road when starting with a place or slow ride on a slippery canvase due to the inclusion of higher initial transmission than usual, and also prevents driving (and especially overclocking) to transmission, too low for the coating by which the car moves .
In all-wheel drive models, Volvo uses constant drive to all wheels with the automatic distribution of traction efforts between the front and rear wheels depending on the state of the road and driving style.
With normal driving on the dry road, most of the traction force (about 95%) is transmitted to the front wheels. If the condition of the road leads to the fact that the front wheels begin to lose the adhesion with the road, i.e. They begin to rotate the fastest rear, an additional share of trafficking effort is transmitted to the rear wheels. Such a redistribution of power occurs very quickly, imperceptibly for the driver, keeping the course stability of the car.
When overclocking the system full drive It distributes the power of the engine between the front and rear wheels so that the maximum possible part of this power is transmitted to the road leather and moveped the car forward.
All-wheel drive car, in addition, it is easier to control the turns, since the power is always distributed on the wheels having the best grip with the road.
To ensure the transfer of traction effort from the engine of the pair of the wheels, which has the best clutch with the road, a viscous clutch is installed between the front and rear wheels of the all-wheel drive car. A stepless change in the ratio of the shafts of trafficking is achieved through disks and viscous silicone medium.
To control the stability and control of traction force, the STC control system is used - (Stability and Traction Control). STC is a system for improving stability by preventing wheeling wheelchair. The system functions, although in different ways, both when moving from place and while driving.
When starting with space on a slippery coating, STC uses the help of anti-lock system (ABS), the sensors of which track the rotation of the wheel. In the event that one of the leading wheels begins to rotate the other than the other, in other words, it starts to slip, the signal is transmitted by the control module of the ABS system, which slows down the rotating wheel. At the same time, the traction force is transmitted to another leading wheel having a better grip with an expensive.
ABS sensors are configured in such a way that this function only works when driving at low speeds.
During the movement of the car, STC constantly monitors and compares the speed of all
four wheels. If one or both leading wheels begin to lose the clutch with an expensive, for example, if the car begins to aquaplast, the system responds immediately (approximately 0.015 seconds).
The signal is transmitted by the engine control module, which reduces the torque instantly by reducing the amount of injected fuel. It happens in stages until the grip will restrict the road. The whole process takes only a few milliseconds.
In practice, this means that starting the wheeling wheel stops throughout the distance of the distance when the speed at a speed of 90 km / h!
The decrease in torque continues until a satisfactory clutch with an expensive restores, and occurs at all speeds starting approximately 10 km / h at the lower gear.
The STC system is equipped with large-sized Volvo models - S80, V70, Cross Country and S60.
To prevent driving is used DSTC control system for dynamic stability and traction control (Dynamic Stability and Traction Control).
Principle of operation: Compared to STC, DSTC is a more advanced stability control system. DSTC provides the correct car reaction to the driver team, returning the car to her course.
Sensors track a number of parameters, such as rotation of all four wheels, rotation of the steering wheel (rotation angle) and the course behavior of the car.
Signals are processed by the DSTC processor. In case of deviation from ordinary values, such as, for example, with the starting side displacement of the rear wheels, the braking of one or several wheels is used, returning the car to the correct course. If necessary, the traction force of the engine will also be reduced, as in the case of STC.
Technology: The main unit of the DSTC system consists of sensors that register:
Speed \u200b\u200bof each wheel (ABS sensors)
Rotation of the steering wheel (using an optical sensor on the steering column)
The angle of displacement relative to the movement of the steering wheel (measured by a gym located in the central part of the car)
Centrifugal security security tools in the DSTC system:
Since this system controls the brakes, Volvo equips the DSTC system with paired sensors (defining the angle of deviation from the course and centrifugal force). The DSTC system is equipped with large-sized models Volvo - S80, V70, Cross Country and S60.
For compact models, Volvo uses DSA Dynamic Stability Assistance (Dynamic Stability Assistance).
DSA is a wheel control system developed for compact models of Volvo S40 and V40.DSA tracks cases when any of the leading front wheels begins to rotate faster than the rear wheels. If this happens, the system immediately (for 25 milliseconds) lowers the engine torque. This allows the driver to quickly accelerate, even on a slippery coating, without loss of adhesion with expensive, stability and controllability. The DSA system is involved in the entire range of vehicles of the vehicle: from the smallest to the maximum. Volvo cars S40 and V40 can be equipped with a DSA system as a factory option (with the exception of cars with diesel engines or engines with a working volume of 1.8 l.).
In order to facilitate touching on a slippery coating, the Traction Control System Traction Control System is used. Tracs is an auxiliary electronic system that facilitates starting from a place that came to replace the outdated mechanical self-locking differential and differential brakes. The system uses sensors to track occasions of any wheel. The use of braking for a stroke wheel increases the traction force on the other wheel of the same pair of wheels. This makes it easier to start on slippery and control at speeds up to 40 km / h. The Volvo Cross Country model is equipped with a TRACS system that facilitates touching, on the front and rear wheels.
To ensure high speed stability at high speed, the other Roll Stability Control system is used by the Volvo XC90. It is an active system that allows you to make steep turns at high speed, for example, with sharp maneuvering. The risk of tipping the car at the same time decreases.
The RSC system calculates the risk of overturning. To determine the speed with which the car begins to roll, a gyrostat is used in the system. The information from the gyrostat is used to calculate the final roll and, accordingly, the risk of tipping. If such a risk exists, the thrust control system is triggered to provide a course stability (DSTC), which reduces the engine power and slows down one or more wheels with an effort sufficient to align the car.
When the DSTC system is triggered, the front exterior wheel (if necessary, simultaneously with the back outer wheel) is brazed, with the result that the car leaves the turning arc. The impact of the lateral forces on the tires decreases, which also reduces the forces capable of tipping the car.
Due to the operation of the system from a geometric point of view, the rotation radius increases slightly, which, in fact, is the reason for reducing the centrifugal force. To equalize the car, it is not necessary to significantly increase the rotation radius. For example, during a sharp maneuvering at a speed of 80 km / h with significant turns of the steering wheel (about 180 ° in each direction), it may be sufficient to increase the rotation radius by half the meter.
Attention!
RSC system will not protect the car from tipping when too high corner speeds Or when the wheels are shred about the border (Road irregularity) simultaneously with the change in the trajectory. A large amount of cargo on the roof also increases the risk of overturning with a sharp change in the trajectory of the movement. The efficiency of the RSC system is also reduced with a sharp braking, since in this case the braking potential is already fully used.
The problem of safety of road transport movements to relate to a very limited set of truly global problems that directly affect the interests of almost all members of modern society, and retains the global level of significance, both in the present and foreseeable future.
Only in Russia, with its highly modest fleet of the fleet of about 25 million cars, more than 35 thousand people die in an accident, more than 200 thousand are injured, and the damage from more than 2 million registered traffic police reaches astronomical dimensions.
Expecting any noticeable positive changes such a catastrophic state of the problem can only be concentrated in the focus of the efforts of society in all directions of its decisions determined by the results of meaningful system analysis.
Essentially, the solution of the movement problem is reduced to solving two tasks independent of each other:
collision prevention tasks;
the tasks of reducing the severity of the consequences of the collision, if it is not possible to prevent it.
The second task is solved solely by means of passive security, such as belts and airbags (front and side), safety arcs installed in the car and the use of body structures with programmable deformation of power elements.
To solve the first problem, the analysis of mathematical collision conditions is required, the formation of a structured set of typical collisions, which includes all potential collisions and determining the conditions for their prevention in terms of the coordinates of the object of the object and their dynamic boundaries.
Analysis of a plurality of typical collisions containing 90 collisions with obstacles and 10 typical tipping shows that the directions of its solutions are:
construction of unilateral multibone roads of the main type, which makes it possible to exclude collisions with counter and fixed obstacles, as well as with obstacles moving along the intersecting directions of one level;
informational equipment of the current network of highway with operational information about hazardous areas;
organization of effective monitoring of monitoring of traffic police by traffic police;
equipment car park Multifunctional active safety systems.
It should be noted that the creation of active safety systems and the equipment of the fleet is one of the most promising areas established in leading developed countries, and is a relevant applied problem, which is currently far from completion. The prospects of active safety systems is explained by the fact that their use potentially allows you to prevent more than 70 typical collisions out of 100, while the construction of the roads of the main type allows you to prevent 60 out of 100 typical collisions.
The complexity of the problem in a scientific aspect is determined by the fact that from the standpoint of the modern theory of management, the car, as an object of control, characterized by the vector of state variables, is an incompleteness observed and incompletely controlled in motion, and the task of preventing collisions in the general case refers to the algorithmically insolvable due to the unpromprepanable changes in the direction of movement of obstacles.
This circumstance creates practically insurmountable difficulties in the construction of full-featured autopilot for cars not only in the present, but also in the foreseeable future.
In addition, the solution to the dynamic stabilization of the coordinates of the state to which the task of preventing collisions in its most complete algorithmically soluble formulation is characterized by both the uncertainty of most dynamic boundaries of the state variables and their possible overlaps.
The complexity of the problem in a technical aspect is determined by the absence of the overwhelming majority of primary information sensors in the world practice necessary to measure the coordinates of the state and their dynamic boundaries, and the use of existing ones is limited to their high cost, heavy operating conditions, high power consumption, low noise immunity and accommodation difficulties on the car.
The complexity of the problem in an economic aspect is determined by the fact that to impart the status of the algorithmic solvability of the problem of preventing collisions, it is necessary to equip the entire fleet with multifunctional security systems, including old cars of low price categories. Considering that the cost of the kernel of hardware, including the sensors and actuators, the most common foreign stabilization systems of the longitudinal and transverse slides of the wheels (ABS, PBS, ESP and VCS) exceed a thousand dollars, the possibility of equipping the acting car fleet seems very problematic. Note that the number of typical collisions prevented by these systems does not exceed 20 out of 100.
Studies show that to solve the problem of dynamic stabilization in full, the following set of variables and their dynamic boundaries is required:
distances to passing cars;
distance required for a complete stop;
speeds and accelerations of wheels;
speeds and accelerations of the center of mass of the car;
speeds and accelerations of longitudinal and transverse slides of the wheels;
angles of rotation and convergence of controlled wheels;
air pressure in tires;
wear of tire cords;
tire overheating temperatures characterizing the intensity of protectors' wear;
additional angles of collapse of wheels arising from spontaneous or intentional turning of fastening bolts.
According to the results of the problem of the problem, its solution lies in the field of intelligent systems that are built on the principles of indirect measurements of all the above status variables and their dynamic boundaries in the minimum possible configuration of primary information sensors.
High-precision indirect measurements are possible only with the use of original mathematical models and algorithms for solving incorrect tasks.
Naturally, for the technical implementation of such systems, it is necessary to use modern computer equipment and means of displaying information, the cost and functionality of which, subordinate to the famous Moore law, "doubles its capabilities and is twice the price of every 18 months," which creates conditions for a noticeable reduction in the cost of hardware Tools of this type of systems.
It should be noted that today the domestic multifunctional active safety systems have been developed providing for the driver information about the approximation to the borders of hazardous modes, and the actual control of brakes, an accelerator, transmission and steering wheel is performed by the driver.
Prices for such systems today do not exceed $ 150-250, depending on the volume of functions, their installation on cars does not cause difficulties, which reduces the sharpness of the economic aspect of the problem for low-cost cars.
For cars of the average price category, the automatic execution of certain functions, such as stabilization of longitudinal sliding wheels, requires additional actuators (controlled hydrolylapanov, hydraulic pumps, etc.), which naturally significantly increases prices for the systems of this class.
For high-priced cars, the automatic execution of most control functions can be provided by introducing into the system of sensors of distances, the state of the external environment, etc.
Common features for intelligent active safety systems of various price categories are indirect measurements of the coordinates of the state and their dynamic boundaries, as well as the indication of the approximation to the boundaries of hazardous modes. The choice of control automation level and necessary for this configuration of technical means remains in this case for the owner of the car of any price category.
As an example of an intellectual active security system, we consider the domestic computer system Inca-Plus.
The technical solutions based on the Inqua-system are patented in Russia, registered in the World Intellectual Property Organization (WIPO).
The main functions of the Inka system include:
measurement of pressure differences in tire pairs and the indication of their deviations from the denominations;
display speeds of wheel rotation and indication of locks and wheel slip;
measurement and indication of additional corners of the collapse of the wheels.
The Inca region includes:
the processing unit and indication of the information (Inca Plus), installed on dashboard (photo1) in a convenient place for the driver;
induction type primary information sensors, measuring the increments of angles of rotation of the wheels (photo 2);
communication cable that switches the sensors with the processing unit and information indication;
the power connector of the Inca Plus block connected to the standard cigarette lighter socket;
Photo1 Treatment and Indication Block Inca Plus
Photo2 induction sensor
Inka system sensors consist of two diametrically arranged permanent magnets stressed inside the rim and an induction coil installed on the brake shield using the bracket.
Inca system sensors are not affected by temperature in the range -40 + 120 degrees, pollution, vibrations, moisture and other real factors. The service life is practically not limited, and their installation does not require changes to the design of the car units.
Inca System Sensors are connected to the processing unit and indication of information on a current scheme, which allows you to fully suppress electromagnetic interference from the ignition distributor and other interference sources.
Inca System Sensors do not require connection to the power supply and do not need to be repeated, adjustments and maintenance during operation.
On the front panel of the Inca Plus block, 4 groups of 3 LEDs were displayed in each, the location of the LED groups corresponds to the location of the vehicle wheels (top view)
The upper green luminescence LED serves to indicate the normal level of pressure in the tire. When deviating from a nominal 0.25 -0.35 bar, the upper LED flashes with frequent 1 Hz.
The average red luminous LED serves to indicate the pressure deviation from the nominal. When the pressure is deviated from the nominal in the range of 0.35- 0.45 bar, a flashing with a frequency of 1Hz is envisaged, with a deviation of more than 0.45 bar-constant luminescence of a red LED. The lower LED of the green glow group is designed to display signals from primary information sensors.
The setting button is located on the end surface of the Inca Plus block and is intended to activate the setting mode of indirect pressure measurements.
The principle of the operation of the Inca-system is based on a precision measurement of the frequency frequency differences of the vehicle wheels arising by reducing the pressure in one of the wheels of the pair and the corresponding change in the static radius of this wheel.
It is experimentally established that for tires with static radii, about 280-320 mm, the change in pressure per 1 bar is accompanied by a change in the static tire radius of about 1 mm.
The accuracy of measurement of pressure differences in steam pairs does not depend on the velocity of the vehicle and the road surface.
Possible distortions arising from slides of the wheels and when moving on the devices, it is found algorithmically and do not affect the measurement results.
The need to set up the system may occur in the following cases:
when replacing or rearranged the wheels;
when changing press denominations;
when indicating non-zero deviations from denominations as a result of various tire wear in steam pairs.
The setup mode is activated by pressing the setting button when the power is on and is fully automatically performed. The completion of the setup cycle is displayed on the Red Right Indicator rear wheel When it is turned on on the interval of 1 second. Nonal values \u200b\u200bof pressures in the tires are installed by the driver on cold tires in the usual way. The indication of locks and slip of the wheels is performed using the LEDs of the wheel sensor status. The blocking of the wheel is accompanied by the loss of the glow on the corresponding LED, the wheel slip at speeds is less than 20 km / h is accompanied by the appearance of the glow on the bouquet wheel LED.
An increase in the inconsistency of the sensor and magnets corresponding to the increase in the angles of the additional collapse of the wheels is accompanied by an increase in the speed on which the light sensor status of the wheel sensor arises.
Table 1 shows specifications Inca Plus systems.
Technical data Inca-systems Table 1
Pressure measurement range, bar
Relative error,%
Car speed range, km / h
Power consumption from network, W
Side network voltage, b
Mass set, kg
Table 2 shows comparative characteristics Foreign systems of similar purpose, the principle of which is based on the direct measurement of pressures in the cavity of the tires and the transfer of information on the radio channel.
Comparative characteristics of systems Table 2
System model
Restrictions on Tire Types
Labor intensity
Lifetime
Speed \u200b\u200bmin. KM / C.
Speed \u200b\u200bMax Km / h
Dismantling wheels
Wheel Balancing
Michelin Zero Pressure.
(France)
required
required
(Taiwan)
Cameless Tires without Metal Cord
required
required
Limited resource power supply sensors
(Finland)
Cameless Tires without Metal Cord
required
required
Limited resource power supply sensors
Tires of one model
not required
not required
no restrictions
The application of a wireless data transmission circuit on the radio channel in the systems under consideration limits their use of tires without a metal cord, which is a radio wave screen, and the design of the pressure sensor placed on the rim inside the tire limits the use of these systems for chamber tires. The magnitudes of overloads acting on the elements of the sensor design and the power elements during the rotation of the wheel are superior to 250 g at speeds of more than 144 km / h. Note that overload in 200 g is noted when the aircraft falling at a speed of 720 km / h and the formation of a 10 m in places in the fall of the funnels. In this case, the instrument arrows break through the dials and thereby retain the instrument readings at the time of the land touch by air.
The mass of pressure sensors of these systems is 20 - 40 grams, which requires additional balancing wheels, and disassembly wheels are required inside the rim. This should add a limited resource of sensor power sources, which is significantly reduced at low and high temperatures.
For Inca-Systems there are no restrictions on tire types, the need to dismantle and additional wheel balancing, by operating deadlines, which is determined by the use of induction type sensors, a wired communication line and magnet arrangement schemes on the wheel rim.
The ideology of constructing the inco-system allows for the increase in the functions of indirect measurements of the state variables and their dynamic boundaries by software without increasing the number of primary information sensors, which ensures both the complete observability and controllability of the object in motion and the solution to the problem of preventing collisions in its most complete algorithmically resolved performance. The relatively low cost of the Inca set and the lack of restrictions on the installation of sensors allow you to equip all car models, including cars of lower price categories.
We will conduct a brief overview of the security systems provided today.
Passive security systems work at the moment of impact. These include: zones of the programmed deformation of the body, seat belts and airbags. Safety belts prevent the driver or passengers "flight" windshield And reduce the risk of serious injury to face and body with a sudden stop. Airbags, revealing when a collision, soften the blow on the head and other sensitive parts of the body.
In the 90s, the norm was considered the equipment of the car with two airbags: the driver and the front passenger. Modern cars have from 4 to 10 or more airbags, each of which provides protection against specific injury at a certain collision. So side airbags, "deployed" in window openings, prevent head injuries with side shocks and tipping. And the side airbags in the racks or backs of the seats protect against damage to the abdominal and pelvic area. The knee airbag prevents the leg injury when hitting the dashboard.
A modern safety belt provides a uniform distribution of the force acting on the human body with a sudden stop. Some Ford and Lincoln models are equipped with an innovative seat belt with an upgrade element that reduces the load. General Motors offers a central airbag disclosed on the right side of the driver's seat, which provides additional depreciation with lateral impact and prevents the driver's head collisions from the head of the front passenger.
Another important element of passive security, which many do not even suspect - the power construction of the car body. The body has specially calculated deformation zones, which, let's start when a collision, dispel the energy of the impact. This task is assigned to the front and rear parts of the car. The cabin case, on the contrary, is made of high-strength steel structures that are not deformed at the moment of impact.
While passive security systems operate directly at the time of the collision, the active safety systems tend to avoid accidents in every way. In recent years, great progress has occurred in this area. But there are also those systems that are in the service are already dozens of years. So the anti-lock brake system (ABS) prevents the wheel lock with a sharp braking, ensuring the stability and control of the car at the time of slowdown. ABS performs continuous monitoring of speed using sensors on all four wheels and resets the pressure in the brake circuit of the blocked wheel.
The anti-slip system is often the secondary ABS function and prevents slipping by reducing the engine power ("Gas Reset") or a loading of the buxing wheel.
The stabilization system uses another set of sensors controlling the lateral movement of the car, the speed of rotation and the angle of rotation of the steering wheel, position throttle valve and much more. If the vehicle moves along the trajectory that does not correspond to the control exposure, then the system with the help of a brake of a particular wheel or a change of engine power, is trying to restore the specified trajectory.
Many modern cars are so smart that they know not only the parameters of your movement at the moment, but also vehicles and objects around you. This is done by a collision warning system that collect information about the surrounding objects with the help of sensors: radars, chambers, laser, thermal or ultrasonic sensors. If the system detects too fast rapprochement with the object, the driver will be warned by sound from speakers, light indication, vibration on the seat or steering wheel. If the time to warn is not enough, the system itself interferes with the management to help you avoid accidents. So in some cars the pressure in the brake system for emergency braking is created and the seat belt pretension is carried out. Some systems even resort to braking.
Another active security system is tracking blind zones. Automakers use various ways to warn. In most cases, this is a monitoring system of blind zones with indication on outer mirrors and sound warning.
There is also a system of monitoring control system, warning about leaving its band using light, sound alarm or vibration. Some systems in addition to this are able to slow down and return the car to their lane. The system, as a rule, is triggered during rebuilding without turning on the rotation pointer.
In recent years, the list of active safety systems has increased significantly. It was supplemented by adaptive headlights, rotating the light beam in the direction of the car movement, lighting the dark areas of the roads in the turn. Active Far Light is able to detect the approach of the counter cars and switch to the neighbor, so as not to blind other road users.
Mercedes on their cars sets the Attention Assist system, which follows the condition of the driver. The system will give a beep if it suspects that the driver began to fall asleep.
Rearview cameras Nowadays, the usual phenomenon, and on many cars included in the list standard equipment. One of the new systems provides monitoring of blind zones at the time of the car's movement by reverse. When crossing your trajectory with a car in the blind zone, the system will warn the driver about a possible collision. Other manufacturers using multiple cameras on the sides of the car create a picture on the display with top view, helping to navigate in narrow places. No less common and the use of radar detectors measuring distance to objects warning about approximation by increasing the frequency of the beep.
Modern car take care not only about the safety of the driver and passengers, but also the security of pedestrians. This applies a special form of the front of the car. Also used the active racks of the hood, lifting it by the back at the race at the pedestrian.
More recently, airbags began to be used on the outer surface of the car. So Volvo released the first car equipped with a pedestrian airbag, unfolding at the transition site of the hood-windshield, to prevent a pedestrian head injury. Some automakers, such as BMW, offer an infrared help system that recognizes a person or an animal in the dark.
Adaptive cruise control helps maintain a safe distance to ahead of the running vehicle using radars or laser sensors. Some systems are able to stop the car on their own, and then start moving again, working in "Stop & GO" mode.
Currently, a technology is being developed, providing cars with the opportunity to exchange information about accidents, detected pedestrians and other vehicles. Also, the system will be able to analyze information on traffic lighting modes, bringing adjustments to high-speed mode to ensure the free passage of intersections, without stopping on the red light ("green wave").
Automotive security systems have passed a long way from the moment the safety belt appears more than 50 years ago. Modern security systems provide a high degree of protection. Nevertheless, there are always directions to improve, reduce the likelihood of road traffic accidents and injury. But first of all, it should be remembered that safety begins with the driver.
If you believe research, from 80 to 85% of transport accidents and catastrophes fall on cars. Auto manufacturers understand that the safety of the vehicle is an important advantage over rivals on the market, as well as that the safety of motion on the road as a whole depends on the safety of one vehicle. The causes of accidents can be different - this is the human factor, and the condition of the road, and meteorological conditions, and the designers have to take into account the entire spectrum of threats. therefore modern systems Security provides both active and passive vehicle protection, and consist of a complex complex of various devices and devices, from the anti-locking system of wheels (hereinafter - ABS) and binding systems to airbags.
ACTIVE SAFETY AND DTP Prevention
The reliable vehicle allows the driver to preserve his life and health, and at the same time - the life and health of passengers on modern, the colors of the slaughtered tracks. The safety of the car is customary to divide into passive and active. Active means those design solutions or systems that reduce the likelihood of a road accident.
Active safety allows you to change the nature of the movement without fear of the output of the car from under control.
Active safety depends on the design of the machine, the ergonomics of the seats and the cabin as a whole, systems preventing the frost, visors, is of great importance. Systems that signal breakdowns that prevent brake blocking or speeding speeds also refer to active safety.
The visibility of the car on the road, which is determined by its color, can also play a role in preventing an accident. So, bright yellow, red and orange car body are considered more secure, and in the absence of snow they are added to their number and white.
At night, various reflective surfaces of the surface correspond to active safety, which is noticeable in the light of headlights. For example, the surfaces of the license plates covered with special paint.
Convenient, ergonomic placement of instruments on dashboard and visual access to them contribute to the prevention of accidents.
If the accident still happened, the driver and passengers are protected by means of passive safety. Most of special devices And passive safety systems are in front of the cabin, because when accidents suffer primarily windshield, steering column, front door of the car and dashboard.
Safety belts are a simple and cheaper tool that is extremely high efficient.
Currently, in many states, including in Russia, their presence and use is required.
A more complex passive protection system - airbag.
Created initially as an alternative to a belt and means that avoids the injuries of the driver's chest (injuries about the steering wheel - one of the most common during accidents), in modern cars pillows can be installed not only ahead of the driver and passenger, but also mounted in the door in order To protect from the side impact. The disadvantage of these systems is an extremely loud sound when filling them with gas. The noise is so strong, which exceeds the pain threshold and may even damage the eardrum. Also, the pillows will not be saved when tipping the car. For these reasons, experiments are carried out on the implementation of security grids, which will continue to replace pillows.
The driver with a frontal impact has the opportunity to injure legs, because in modern cars, pedal nodes should also be injurious. When a collision in such a node, a pedal separation occurs, which allows you to protect your legs from injuries.
Click on the picture to enlarge
Backseat
Children's car seat and special belts that reliably fix the body of the child and warn his movement through the cabin in case of an accident, can ensure the safety of completely young passengers, for which conventional safety belts are not suitable.
With a sharp occurrence of overload, affecting the passenger's body, it is possible to damage the cervical vertebrae. Therefore, the rear seats, like the front, are equipped with head restraints.
Reliable seats fastening is also very important: 20G overload should withstand the passenger seat to ensure proper safety in the event of an accident.
Design features
As already mentioned, the car itself should be designed to ensure maximum safety to people. And it is achieved not only by ergonomics. Not the last value is the strength of various structural elements. One elements should be enhanced, and others - on the contrary.
So, to ensure the reliable passive safety of passengers and the driver, the middle part of the body or frame should have increased strength, and the front and rear parts are opposite. Then, when fermentation of the front and rear parts of the structure, part of the impact energy is spent on deformation, and a stronger middle part easily withstands the collision, not deformed and breaks. Those parts that must be crumpled when hitting are made from fragile materials.
The steering wheel should endure the blow, but not to break the driver of the breast and rib.
Therefore, the hubs of the steering wheel are made of large diameters and coated with elastic shock absorbing materials.
The windows in cars also serves passive safety goals: unlike conventional window glass, it do not break into large pieces with sharp edges, but crumbs in small cubeswhich can not apply cuts or the driver or passengers.
Technologies in the service of active safety
The modern market offers many reliable and efficient active safety systems. The most common and famous - anti-lock systems which prevent slipping wheels arising when blocking the wheels. If there is no slip, then the car does not enter.
The ABS allows you to perform the maleuvra during braking and fully control the movement of the vehicle before it is complete.
Electronics ABS receives signals from wheels rotation sensors. It then analyzes the information and through the hydromodulator affects the braking system, for short periods of time "releasing" the brakes so that they are rotten. This allows you to avoid drift and slip.
Anti-slip systems, which analyze data on the rotational speed of the wheel and control the torque of the engine are constructed on a constructive basis.
Currency stability systems increase the safety of the car by holding the direction of its movement. Such devices themselves can determine an emergency, interpreting the driver's actions in comparison with the auto motion parameters. If the system recognizes the situation as an emergency, it begins to adjust the movement of the car in several ways: slotching, changing the torque of the motor, adjusting the position of the front wheels. There are devices that also signal the driver of danger and injected pressure in the brake system, increasing its efficiency.
Reduce the mortality of shot down pedestrians by 20% allow pedestrian detection systems. They recognize a person at the rate of car traffic and automatically reduce its speed. The use of a special airbag for pedestrians in a complex with this system allows you to make a car even more secure for those who have no car.
In order to prevent blocking rear kers, Apply a pressure redistribution system. Its task is to align the pressure of the brake fluid, based on sensor readings.
findings
The use of active and passive security systems reduces the risk of accident and injuries if the accident is still happening.
Passive safety is built around the absorption of the energy of the body parts, the engine or the passenger body and the prevention of hazardous deformations of the design, which can lead to injuries located in the salon of people.
Active safety is aimed at preventing the driver about the threat and adjustment of control systems, braking, changing torque.
Technologies in this industry are developing rapidly, and the market is constantly filled with new, more modern and efficient systemsMaking traffic on the roads is all safer every year.
Security systems are the central direction of development of modern cars. A serious evolutionary stage in this direction began since the appearance of the first intelligent devices that prevented or reduced the risks of the accident. Today, such systems form a whole reservoir of funds that are called the active safety of the car. This is predominantly electronic deviceswhich can monitor certain parameters of the state of the machine, in a timely manifold signals about possible threats.
The concept of active safety systems
You will be interested:
To understand what such systems are presented, it is necessary to begin to consider the principle of operation of the mechanisms that are their opposite. That is, it will be about passive security systems. As already noted, these are mechanical devices, and traditionally not related to electronic controls. They are triggered at the moments when external impact is physically recorded. As for the active safety of the car, this is a complex of devices that are focused on the prevention of accidents, as well as minimizing the risks leading to other negative consequences. It may not only be electronic devices With sensors, but also structural parts of the machine. Moreover, the effectiveness of such systems also affect the performance of the car, which are not directly related to security tasks.
