Types of car drives. Front, rear or four-wheel drive? Temporarily connected four-wheel drive

The full drive system is the transmission design that distributes the torque to all four vehicles. Torque is a certain collector of all horse power Engine in one harness. Respectively, the more of this torque, the stronger and faster car will gain a move. It is worth considering that the torque is completely dependent on the volume of the engine. The liter motor will not have an excellent torque, and the machine will accelerate significantly slower.

If you want your car to accelerate quickly, then take a model with a large engine volume, for example, two-liter or three-liter. They will perfect their functions perfectly, and you will feel confident of the wheel of such a powerful and fast car.

Until the 80s, everything was mistakenly believed that only powerful all-terrain vehicles with an impressive road clearance and other options that increase the permeability. But after the appearance of the Quattro system on car brand cars, the all-wheel drive system began to be considered also to improve challenges W. simple cars. In such cases, the handling of the vehicle, its passability has improved significantly in conditions of a smooth roadway even on ice. Such a system is equipped and sports carsFor example, Lamborghini and Luxurious Porsche.

Connected full drive

Most inexperienced drivers are confident that every SUV has a four-wheel drive. This is not quite the case, because some SUVs are equipped with a full drive system "part-time", which translated from English means "partially included". This system does not imply permanent job full drive. In urban conditions on a good asphalt, the car operates in rear drive mode. In order to translate the car to the operation of the full drive, you must click on the selector lever dispensing box and bring it to the right position. In fact, this is done for considerations of savings and security, because you have the opportunity to include a four-wheel drive for a short time, and not use the four-wheel drive constantly.

The permanent operation of the full drive in the city may lead to the destruction of some component parts transmissions. This is fraught with manageability and to the car drift. main reason these troubles lies in front bridgewhich on the road with a solid coating should be turned off to bring the car to the rear drive system. Thus, you will reduce the permeability of the SUV. For these reasons, the cost of such cars in the market decreases significantly. Everything else, this SUV with a large appetite is a versatile car with rear-wheel drive. On such an SUV, it is better to move on an asphalt road and avoid off-road.

Automatic full drive

There is a similar all-wheel drive system that is called "Ondemand". That translated into Russian means "on demand." Its main advantage is automatic launch All-wheel drive mode. In the usual state, the SUV will operate in the rear drive mode. But if you get into difficulty places, the electronics will notice the slip of the wheels and automatically connect the front axle. In this case, you can be sure that the car will unhindered off-road off-road. This is because with rear bridge The system takes the torque and evenly distributes it between the front and rear axle.

Sometimes 40% turns on the front bridge, and the remaining 60% remaining. Of course, it depends only on a particular SUV. IN best case The system will dispense between the front and rear axle the same torque, that is, 50 to 50. Also, some car are an optional, so the "Ondemand" system connects the rear axle only if necessary. Everything else, the driver can also independently activate this system if it feels that a four-wheel drive is necessary for the passage of this section. The system works perfectly in snow conditions, so modern "parcktails" is equipped with it.

Permanent full drive

Cars with the "Full-Time" system always have a four-wheel drive on all wheels without exception.

The expression "Full-Time" means " full time"Or just" all the time. " This system Two varieties can be divided: off-road and urban.

The SUV with the urban system "Full-Time" is equipped with an inter-axis differential, it has the opportunity to move in the full drive system. The only minus is the lack of blocking the inter-track differential, which sometimes leads to slippage of the connection between the front and rear wheel.

Therefore, it is better not to use this system on the crossed or swamp terrain, otherwise there is a possibility that you get stuck in a difficult place. Truly powerful and passable cars with off-road system "FULL-TIME", which better competitors overcome the conditions of serious off-road. SUVs are equipped with a blocking of an interstole differential. With such a complete set, the car is quite more expensive, it can be said that the price is much higher than for many all-wheel drive cars.

In conclusion, I would like to say that some SUVs are actually them and are not. It's just massive and overall cars With no less impressive off-road ambitions. So if you prefer to drive around the roadbed, but still want a all-wheel drive SUV, then just buy normal car with full drive. He is not worse than impressive crossovers, everything else, passenger all-wheel drive cars are much cheaper than SUVs.

Every motorist knows well or at least heard about different kinds Car drives. But if all the same, there are those who did not hear about it, we will try to figure it out. The fact is that the torque from the engine is transmitted to the wheels (it is necessary for the car to go), just how many wheels this torque will receive, depends on the type of actuator. There are three types of drive: full, rear and front. We will talk more about each of them and find out what they are good and what their shortcomings they have.

Types of car drives

If the motor energy is transmitted to all four wheels, such a drive will be called complete. He, in turn, is also different. It happens that the distribution of energy between the rear and the front axles is uneven. For example, U. Lamborghini Gallardo., 70% of energy falls on the rear axle and only 30% on the front. Equipment is also possible, but in the event of a slide, the rear is also included in the operation. One of the representatives of this car - Mitsubishi Outlander.. It also happens the distribution of energy in absolutely equal shares.

pros all-wheel drive cars They are in excellent patency and opportunities to start from the place without slipping the wheels almost on any coverage. Cons - a sufficiently heavy and expensive type of drive. And the most important thing is that at some moments the behavior of the car on the road can be unpredictable. This may occur due to the uneven distribution of torque on the wheels, which is possible in a situation where, for example, one wheel loses the adhesion with the road. Therefore, we can say that this type The drive requires a neat driving and race through the serpentine performed by the unprofessional rider contraindicated (however, as on any other drive :)).

With rear drive, how can you guess, the engine energy goes entirely on rear wheels. This type is characteristic for american cars. It is also found on high-class European I. japanese cars. The advantages of this drive include excellent dynamics and handling. The lack of vibration transmitted to the body and the steering wheel is positively affected by comfort for both the driver and passengers. Of the minuses it should be noted a tendency to drift when attaching to slipping road.

The front-wheel drive cars receive all the engine energy to the front wheels. Owner of this are most modern cars budget classYes, and expensive models come across. The lack of cardan creates a smaller weight, but the front of the car is still heavier than the back, as a result of which the car is susceptible to driving on an inhomogeneous coating, although much to a lesser extent than cars with rear-wheel drive. The pros will be attributed to the simplicity of use, low cost and practicality. Learn to drive a car with front-wheel drive is easier than rear-wheel drive and all-wheel drive, which is good for beginner drivers.

What a drive is preferred

BUT! All these arguments about the drive today, by and large, meaningless, since most modern cars are equipped with a multitude of stabilization systems, and if you get behind the wheel of the rear-wheel drive BMW, you can immediately feel how nice to manage and how predictably he behaves in difficult road conditions Unlike Vaz Kalina with front-wheel drive, for example.

Therefore, answering the question of which drive is better, you have to state that there is no best drive. You need to learn to manage a hard drive and feel his behavior on the road. Be attentive driving and respond to change on time road coat and the road situation as a whole.

What drive is better? Before answering this question, consider some concepts.

Sustainability - this is the ability of the car in the absence of driver actions (rotation of the steering wheel, changing the position of the gas pedal,
Turning on the brakes, etc.) to withstand the specified direction of movement without tipping and side sliding wheels.

Turning - The property of the car to change the trajectory of the movement under the action of lateral forces (wind strength, etc.) with a fixed steering wheel.
If the driver does not rotate the steering wheel, but at the same time:

- Radius of rotation increases - insufficient rotation;

- Radius of rotation decreases - rectified redundant;

- The rotation radius does not change - the rotation is neutral.

The car with insufficient turning is best sustainable, since under the influence of lateral strength, he seeks to move along the curve of a larger radius. At the same time, the centrifugal force decreases and the vehicle restores the movement in the same direction.

Controllability - The ability of the car to change the direction of movement in accordance with the driver's control influence. It is closely related to stability. So, with lateral slides (drip) of all wheels, the car can become unmanageable.

Template to drift More from leading wheels. For example, with a sharp touching from the spot only they. To exclude the drift, it is necessary that the force of the clutch of the wheel with the road was more than the amount of the forces attached to it. The drive wheels are already loaded with a traction force or engine braking force. Therefore, when the lateral influences appear, they are earlier than the slave losing the clutch with the road. The front-wheel drive car, if it moves without luggage and passengers, the rear axle is also prone to drift, since it accounts for less weight than on the front wheels. Accordingly, there is less clutch power with expensive.

Rear-wheel drive car.

When moving in a straight line in the case of lateral impact of wind on the car, the leading rear axle, more prone to the drift, begins to shift towards the action of the perturbation force (Fig. A). The car turns around the point lying on the continuation of the front axle (turning pole). At the same time, a centrifugal force arises, which acts in one direction with the lateral impact of the wind and seeks to increase the skid.

In turning to the vehicle, the centrifugal force is valid, and when driving rear axis It increases, therefore, "striving" to turn the car towards the drift. Accordingly, rear-wheel drive vehicles for the most part have redundant turning.

Simplified schemes of forces acting in the occurrence of lateral wind power: a - on the rear-wheel drive car; b - on the front-wheel drive car; V is the power of the wind; O - Pole turning; F - centrifugal force; F1 and F2 - transverse and longitudinal comprehensive centrifugal force.

Front-wheel drive car

In the case of exposure to the side wind, the front axle drift begins on a direct front-wheel drive car. The emerging centrifugal force (Fig. B) acts in the direction opposite to the drift and prevents it. In the turn, when driving the wheels of the front axle, the increased centrifugal force "seeks to return the car to the previous trajectory. Therefore, the front-wheel drive vehicles for the most part have insufficient turning, so they behave more stable than the rear-wheel drive cars of the same class, especially on wet and icing road.

Four-wheel drive plug-in.

In transmissions of this type, there is necessarily a handout. It may have a lower transmission, but on most of the models there are no inter-axis differential. In this case, the second bridge (as a rule, the front) is connected only to off-road movement. On dry asphalt, this will lead to a deterioration in stability and manageability due to the inevitable slip of the wheels, as they will not be able to rotate with different speeds.

With the front axle disconnected, such a car behaves almost like rear-wheel drive. On vehicles with inter-axis differential, the inclusion of the full drive is permissible and on a solid dry road. This increases the stability of motion by redistribution of traction efforts by four wheels.

Turning at the same time changes, for example, transfers from excess to neutral or insufficient, since all the wheels become leading. However, the movement with a full drive increases fuel consumption due to power loss in further transmission units.

Four-wheel drive connected automatically.

In these transmissions, the torque begins to be transmitted to the second axis only when the leading wheels slip. Due to the redistribution of traction efforts, the slip can stop, and the stability increases. If the transmission is installed in the viscous food, then with a significant slippage of the drive wheels, it is possible its sudden full blocking (Hampi effect).

With curvilinear movement (in turn), it causes an unpredictable behavior of the car. The driver may not have time to adequately react and take the necessary actions to maintain control over the situation. Cars having friction clutch from electronically controlis not subject to such an effect, since the blocking is automatically carried out on a specially selected dependency. In the absence of slipping wheels, these cars on a solid and dry road have stability and handling practically the same as the front-wheel drive.

Permanent four-wheel drive.

In such transmissions, there is necessarily an inter-semicircle differential, which can be blocked as follows:

independently by the forces of internal friction ("Torsen", "Quavif");
using electronics;
forced driver (rigid lock).

There are no differential lock cars, and the slip is stopped by an electronic counter-test system, which slows down the wheels by regular brake mechanisms. The behavior of the car with a constant full-wheel drive depends on the distribution of the torque between the bridges. If a larger torque is transmitted to the front axis, the car characteristics will be closer to the front-wheel drive. When the power is distributed over the axes of 50/50, the stability and manageability indicators will be something mean between the front and rear drives.

For example, turning may be close to neutral. The distribution of the torque depends on the coefficient (degree) of blocking the inter-axis differential. The more this indicator, the more intense the redistribution of traction efforts and, accordingly, the change in the behavior of the car. In the self-locking differential, the blocking coefficient is a magnitude of constant, not dependent on the conditions of movement.

Electronic control is more optimal than the strength redistributes and accordingly changes the behavior of the car. Full blocking by the driver of the mid-scene differential is allowed only when driving in bad road conditions and provides maximum permeability. Patency with partial lock below, since it requires a wheel slip. When troubleshooting the wheelchair the wheels increases the load on the transmission, brakes and the engine, which leads to some increase in the wear of parts and fuel consumption.

What to choose?

To answer the question, a car with which transmission to give preference, it is necessary to accurately represent the main conditions for its operation. For off-road, it is best for permanent four-wheel drive with full blocking of the inter-axis differential and downstream transmission. Not bad for such purposes the driver connected by the driver.

Increase the permeability and self-locking inter-track differentials. Lovers of high-speed motorways are preferable to the front or permanent four-wheel drive without a dispensing box, as cars with such a transmission for the most part are designed for this purpose. The connected automatically four-wheel drive is quite suitable for those who are forced to quickly move on bad roads.

Such machines behave well on the highway, and their permeability of off-road them are higher than that of the front and rear drives. Supporters of calm movement on asphalt is quite enough rear-wheel drive car. Each car has its own critical speed of turning in which the skid begins.

And although all-wheel drive stability and handling in some cases above, it is not worth exaggerating their capabilities, as they can also be in a cuvette. Stop driving a car different waysThe simplest of them depend on the type of transmission and are shown below.

When driving a rear-wheel drive car you can not slow down. You should turn the steering wheel towards the drift and at the same time reset a little gas. No need to let the accelerator completely, otherwise the engine braking will begin. When the thrust force decreases, the skid may stop. Only after that turn steering wheel in the right direction.

On the front-wheel drive car it is necessary to take several other actions that depend on which axis has begun. If it appeared on the back - you need to add gas, send the front wheels to the side of the selected trajectory of the movement and they will "stretch out" the car from the drift. When the front drive axis slides, it is necessary to slightly reset the gas before stopping the wheel slip, and only after that, if necessary, turn the steering wheel to the selected path.

All-wheel drive cars due to a wide variety of transmissions features have quite different characteristics. Therefore, it is difficult to determine the procedure for all of the procedure for coming out of the drift. Despite common features In the behavior of cars within its type of drive, each model vehicle behaves differently, especially on large speeds Movement.

This is connected with many constructive features - kinematics suspension, distribution of the weight load on the axes, using various electronic systems (anti-test, stabilization of movement, etc.), characteristics of used tires, etc. When replanting with an unfamiliar car, especially with another type of drive, it is necessary to add time to addiction, compliance with maximum caution when choosing a movement speed, especially on slippery road surface.

Dispute disputes in the driver's concoct about front-wheel drive Car better or rear. Each makes their arguments. But no one in the right mind will deny that without availability positive qualities In whatever the device, no manufacturer will make it at a loss. It remains only to us to understand all the advantages and disadvantages of the front drive from the car.

Front wheel drive.

Let's start with the transmission device front-wheel drive car and the history of her appearance. With the front-wheel drive design, the torque from the engine is transmitted to the front wheels. This type of car drive or, in english transcription, FWD (Front Wheel Drive) began to apply massively in the machines a slightly later rear. In 1929, he began to use Carl Wan Ranst "Cord L29" in the serial production of the car. In the 70s and 80s, there is a sharp increase in the production of front-wheel drive cars. Today, their number significantly exceeds the release of rear-wheel drive models. This is mainly massive and not expensive models of cars. Depending on the type of engine installation, the following car layouts distinguish with front-wheel drive: Longitudinal installation of the engine in front of the axis, the longitudinal installation of the engine over the axis, the longitudinal installation of the engine over the axis, cross set Engine in front of the axis, the transverse installation of the engine over the axis, the transverse installation of the engine over the axis.

Driver front drive car.

Mix three types of layouts power aggregate for front drive:

Sequential layout at which the engine, main gear and the gearbox is placed on each other on one axis;
With parallel layout, the engine and transmission are located on parallel to each other axes at one level in height;
The last type is "storey" layout - the engine is located above the transmission.

Modern technologies make it possible to practically equalize the front and rear-wheel drive cars from the point of view of consumer qualities, safety and manageability, but we will still analyze the advantages and disadvantages of front-wheel drive cars. So, about the advantages:

front-wheel drive carsare usually more compact, their assembly is less costly, therefore, they are more economical and cheap;
due to the fact that the front leading wheels are loaded quite strongly due to the engine, the passability of the front-wheel drive car in most cases is significantly better than that of the rear-wheel drive machine;
with insufficient driving experience, front-wheel drive car easier to master, especially when parking in winter timesince its drive wheels direct the car more accurately to the parking lot;
the energy generated by the engine is used when turning with a large efficiency, since the front leading wheels rotate, and do not move by tangent;
in the cabin there is no need to place a cardan tunnel, due to the lack of a cardan in the design, in connection with which the volume of the cab is increasing.

However, despite a large number of positive moments, cars with front-wheel drive Possess and sufficient disadvantages, namely:

they have a bad, in comparison with rear-wheel drive, maneuverability in turns due to the limited angle by hinges of equal corner speeds (Sls);
due to the simultaneous execution by the front wheels of two functions - thrust and turn, the rear wheels simply "dragged" behind them, which leads to insufficiently "acute" handling;
the engine is rigidly fixed with the car body, and this leads to the transfer of vibrations from the power unit on the body;
when accelerating the machine on its steering wheel, a reactive force is transmitted;
due to redistribution when starting the load back, the front wheels are unloaded, which leads to a challenge of the car;
for the front-wheel drive car there is a capacity limit. When installing the engine more powerful 200 hp Significantly increases the load on the nodes of the chassis, which leads to a bad handover of the machine.

All of the above says that before starting to manage front-wheel drive car, you need to thoroughly examine theory, if possible with an experienced instructor. It is particularly attentive to be when driving in a slippery road and remember that the yield from the rear-wheel drive and front-wheel drive machines differ radically.

If the motor task is to create a torque, then the transmission is assigned a role in its transmission to the drive wheels. Depending on which of them - front or rear - are connected using a transmission with an engine, the car is considered an editorial or rear-wheel drive. In this article, you will learn what the rear-wheel drive is different from the front and what the advantages and disadvantages of both of these schemes.

The first cars were produced on the rear-wheel drive scheme. This is explained by the simpler engine location, gearbox, rear axle gearbox along the longitudinal line of the car case. The flexibility of the connection provides a cardan shaft.

The rear axle, in the casing of which there are two semi-axles with wheels, is located at a right angle to the Cardan axis. For such a layout I had to create a full-size gearbox. The complexity of its device lies in independence of two rear wheels: When turning, the internal moves faster than the external one.

The operation of the gearbox to see is quite simple: it is enough to lift the jack one of the rear wheels, start the engine and turn on the transmission (laying under the front wheels of the shoe). The wheel standing on the asphalt will be motionless, and hanging in the air will begin to spin. This is the operation of the differential distribution torque between the rear axle semi-axles.

Front drive: device and reasons for popularity

The principle of transmitting the rotation of the motor, the gearbox shaft on the wheels is similar to the rear-wheel drive: a gearbox with differential and cardan shafts. The difference is in the constructive solution of these nodes and aggregates.

The front wheels, being leading, demanded a closer placement of the PPC to themselves. This made it possible to place a bunch of engine-gearbox on one axial line with wheels in the front engine compartment. Cross placement of the motor Forced engineers to create a more compact engine and the speeds of the speeds while maintaining their capacities. Therefore, despite the emergence of an experienced first sample of the front-wheel drive car at the beginning of the 20th century, they have become massively produced only in the second half of the past century.

If the gearbox, the gearbox in such a layout is similar to the rear-wheel drive, then the cardan has a significant difference. In the front-wheel drive scheme, shruses are involved, or ball gearbox gearboxes. If Cardana Cross has two degrees of freedom, then the shruses connect two semi-axes more smoothly. The angle of this articulation reaches 70 ° without serious, unlike cardan, wear of rubber parts. Also, shoes allow you to change the angle of rotation of the wheels - control the car.

Comparison of two types of drive: their advantages and disadvantages

Despite the differences in the details of the layout, the front-wheel drive is designed with the placement of the motor in the area of \u200b\u200bthe front wheels. The rear-wheel drive scheme is more flexible in this regard and allows the motor to be anywhere. There is an adjustable, medium-engine (in front of the driving wheels) and the rear-engine layout. To understand what the rear-wheel drive differs from the front in practice, it is necessary to compare their strengths and weaknesses.

Pluses of rear leading wheels

Rear-wheel drive allows you to achieve high machine maneuverability due to lower limit on the angles of rotation of the front wheels.
Good sustainability on the ground: the leading steam works along the front pair of Kae.
The elongated bunch (motor, driven front wheels and the leading rear) allows you to more gently control the machine when driving - uncontrollable demolition from the led beam cloth.
When starting from the place, the mass of the body is transferred back, increasing the clutch of the tires with the road.

disadvantages

Rear-wheel drive is more inclined to drift.
Such a scheme requires a larger working volume, not allowing minimizing body.

Problems of front drive

Concentrated Mass in Front motor compartment (Engine, gearbox, gearbox, semi-axes, shoes) eliminates proportional toolting on the body.
Overclocking from the place often occurs with the slip due to the weight transfer of the body back.
When driving the car on the road is more difficult to keep due to combining in the front wheels of the managerial and drive function.

Dignity

Such a layout makes the car more passable on the wet soil: she drags the car, like in a tug, and does not push the entire weight in front of them, as with rear drive.
The front-wheel drive gives the machine less weight, the compactness of the placement of the aggregates, which makes it easy to modify the body in two and even the single-visuous layout option.
The inhabitual combination of the control of the machine both in speed and in the direction allows you to better "feel" the steering wheel.

Modern technologies compensate for many difficulties of the front and rear drives, so the choice often depends on the personal taste of the user, and not the possibilities of the machine.