The basis secure drivingwhich brings pleasure is the most complete control of the forces affecting the car. The security of the control is the most important aspect taken into account in the process of creating a running system, as well as a BMW car drive.
Tighten the effect of dynamic forces (whether it is vertical, transverse or longitudinal) different waysTo which refers:
- skill handling;
- neat braking;
- the speed and sensitivity of the shock absorbers and the system of elastic elements.
Following all the above factors makes it possible to maximize driving and get the maximum satisfaction even from sports driving on the disgusting road surface.
Why do you need a complete drive?
Initially, all-wheel drive versions of BMW were calculated on the definition of the most acceptable parameters of the traction force and the ability to preserve the initial state in various influences characteristic of the movement. Only 25 years later, the designed all-wheel drive system BMW XDrive was able to embody this mission into reality, and, on the scale that does not have similar worldwide. This intellectual system is due to rapid response, variability and errorlessness has the ability to adjust the effort in cases where it is converted to the dynamics of motion. This technology was developed in such a way that the maximum apply all the advantages of the allocation of effort among four wheels and get rid of or at least reduce the characteristic disadvantages.
In the root understanding, the all-wheel drive system is aimed at improving the traction force when driving on country or slippery roads. At the same time, it is necessary to face some flaws arising from the ineffective distribution of efforts that may be expressed in the unsatisfactory qualities of the chassis; in limiting the susceptibility of the steering wheel to turn when driving on large speeds; In the lack of comfort when performing various maneuvers. All these shortcomings are very much paying attention, especially if compared with the rear-wheel drive system characteristic of the BMW.
In the process of creating the first full drive of the BMW designer, they were able to make superbly to connect the advantages of the proven to establish themselves with best side Rear drive and all-wheel drive system.
Great speaker on turns - great safety in winter
It should be noted 1985, in which the BMW 325IX was demonstrated on the car dealership, conducted in Frankfurt (IAA). In this model, it was clearly traced chief Principle Full drive: a big dynamics on turns leads to a smaller danger in winter. Main distinctive featureexcretion of this car among the similar to it is an unusual allocation of efforts between the wheels. Instead of the usual equal weight distribution german company Suggested the option where, when moving 63% of the torque, it falls on the rear axle, and 37% on the front. This made it possible to maintain the exact execution of turns.
Wheel transmission rear bridge It contains viscous blocking elements, which, in case of dynamic situations, have the ability to coordinate the power flow. This means that in case of need, for example, turning the rear wheels, the torque will be redirected to the front bridge. Despite the fact that the control of locks occurred automatically, the anti-lock mechanism was always in working condition. In practice, this concept worked in conditions when the car could show all its advantages:
- when accelerated during the output from the turns, the thrust force was optimized;
- in the period, a wet road coating, the transfer of effort was happening without slipping;
- when moving on ice and snow, safe driving qualities were provided.
The need for electronic efforts distribution
The developed electronic regulatory systems opened up new opportunities to optimize traction, dynamics and stability during the movement of all-wheel drive cars.
In 1991, the next one was presented model BMW. 525IX, in which, when diagnosing this state, the electronic system took into account the speed of the rotational speed of the wheels coming from the anti-lock mechanism, position data throttle valve Motor and brake system status.
Distribution of the drive moment with normal ride in the ratio of 36% on front axle And 64% on the rear was provided by a multi-disc clutch, adjustable stepless and located in a dispensing box. This electro-hydraulic clutch in order to avoid situations with the turning of each individual wheel adjusted the power flow arising in main Transmission rear axle. Combining the front bridge occurred at the expense of the power take-off device. With help cardanian Vala Attached the differential of the rear axle.
Lock dispensing box It was electromagnetically carried out, therefore, even in difficult conditions, resistance during the move was provided automatically. For overclocking, both on the smooth and soil road canvase, due to the adjustable blocking of traction, it was always enough.
In 1999, the BMW X5 was also introduced four-wheel driveWhat led to the improvement of effort allocations due to electronic control. This model has become the first in the SPORTS Activity Vehicle), in which the torque was distributed in the following ratio: 38% on the front wheels and 62% on the rear.
In global performance, the free inter-seed differential controlled the power flow among the front and rear wheels. The braking control effect (individual for each wheel) provided the necessary blocking for stability while driving and optimizing traction force.
BMW X5 also contained:
- auto brake mechanism (ADB-X);
- dynamic Control System Dynamic Control (DSC);
- descent speed limit system (HDC).
The combination of all of the above characteristics made a car suitable not only for a sports drive, but for driving along the road surface, far from perfection.
Intelligent four-wheel drive BMW XDrive: speed, accuracy, advance
In 2003, the BMW X3 model was presented, from which the use of a new generation began all-wheel drive systems. In parallel with this car, the four-wheel drive began to use in BMW X5. In this BMW XDRIVE system, the variational distribution of the torque between the front and rear wheels is preserved due to the electronic multi-disc clutch with a longitudinal lock. This clutch function was provided by the system of dynamic coursework control (DSC), due to which the XDRIVE system was determined with the new limits of accuracy and speed of the distribution of drive moments caused by the situation. In addition, this system confirmed the status of an "intellectual full drive", as it became possible to predetermine the risk of slipping the leading wheels and counteract it through the allocation of effort.
Constant improvement of XDrive still allows you to optimize the force of thrust, resistance when driving under conditions of unsatisfactory condition road coat and the dynamics of movement on turns. This system is as successful used for BMW 3, 5, 7 series models.
Improved maneuverability and optimization of speakers on turns using new XDrive and DSC configuration methods
In vehicles with a complete drive system, currently having a XDrive system, it is possible to customize the optimization of the dynamics, which is particularly noticeable, as a rule, on turns. Effort when performing rotation is mainly directed to the rear axle to improve maneuverability. When leaving the turn to make the most optimal traction, the initial percentage of the front and rear axle is restored, which is 40:60. The electronic system for regulating the dynamics of movement contributes to the gradual effect on braking, and also provides stabilization of the drive moment. Due to the same system, under different circumstances, it becomes possible and effective resistance to defective turning.
The XDrive and DSC control electronics in case of a strong output of the outward wheels, the back wheel is specially slows down, located closest to the turning center. As a result, the force of thrust is lost, but, at the same time, this loss is reimbursed by increasing the drive power.
Dynamic Performance Control - the highest accuracy of the allocation of effort
Combination bMW systems XDrive and Dynamic Performance Control (Motion Dynamics Management) significantly increase the ability to most effectively optimize the traction force and car stability when driving. The Dynamic Performance Control system is supplied on the BMW X6, X5 M and X6 M model, since a delineated allocation of force occurs between the right and left rear wheels.
Thanks to such a distribution of the moment, the entire range of speeds is accompanied by an optimal sensitivity to steering and lateral resistance. With an excessive turning of XDRIVE, effort redistributes, reducing the drive moment on rear wheelsAnd Dynamic Performance Control reduces the effort directed to the most loaded rear wheel, due to its arrangement to the rear wheel, located closer to the turning center. In case of insufficiently turning, these system is triggered in the opposite way.
The stabilizing action of the Dynamic Performance Control is manifested even when the driver is released during the movement of the gas pedal. Special devicesThe main transmission of the rear axle contributes to the variational distribution of efforts both in the situation of a sharp change in the load and with forced idle.
Video Test Drive Striving BMW E34
xDrive - the inscription on BMW cars is not just a small addition of a small addition, this is the first indicator of a difficult drive in the car. Consider the principle of operation and history of occurrence.
The content of the article:
Good control over the forces that interact on the car while driving is the first thing you need for safety while driving. Such aspects of BMW engineers take into account primarily when developing a new model.
XDRIVE inscription on the front wing car BMW. It is not enough, it is not small tuning Or some specific addition. Such an inscription says that a four-wheel drive is installed in BMW.
The beginning of the existence of the XDrive system
BMW car specialists allocate 4 generations. It is rumored that in 2017 engineers want to present a new generation of full drive.
First generation
The system of full XDRIVE drive is since 1985. The torque was distributed according to the principle: 63% was released on the rear axle and 37% on the front axle. The composition of such a full drive included blocking the differential of the mid-scene and rear interclays using a clutch viscosity.
It often happened that inexperienced drivers forgot the principle of using the system, and she quickly faced. But still, those who used BWM cars without XDRIVE and with this system, argued that the driving difference was essential.
Second generation
The beginning of the second generation of XDRIVE falls for 1991. This time, the distribution has changed a bit, now 36% fell on the front axis and 64% on rear wheels. Inter-seed differential Blocked using a multid-wide coupling on electromagnetic control. Rear inter-wheeled differential Blocked using a multid-wide coupling based on electro-hydraulics. Thanks to this innovation, it was possible to redistribute the torque between the axes in any ratio from 0% to 100%.
Many motorists say that it is from this generation many BMW cars began to equip the XDRIVE system. Yes, and driving a car with such a system has become pleasant and safe. At one time, these cars began to enjoy in great demand and quickly won a positive reputation.
Third generation
1999 was the beginning for the third generation XDRIVE. The distribution of the torque on the axis with ordinary driving was 62% on the rear and 38% on the front axle, and the inter-wheeled and inter-axis differentials were free. The interlocking differentials is made electronically and to help to complete the drive, a dynamic control system of the vestability of the car appears.
Fourth generation
In 2003 allocate last generation XDrive systems. The torque is distributed in a ratio of 60% on the rear axle and 40% on the front axle of the BMW car. The inter-axis differential is performed using a multi-disc friction clutch, and control using electronics. The distribution of torque is still possible from 0 to 100%. The interlocking differential lock occurs by electronically, thereby interacting with the system of controlling the dynamic stability of the car (DSC).
Fans bMW brands It is said that thanks to such a XDRIVE system appeared cars With good permeability, courseworthy, and as a result, safety has improved.
The XDRIVE system is used for BMW cars with rear-wheel drive transmission. The torque is distributed between the axes due to the transfer box. With itself, it represents a toothed transmission to the front axle, which is controlled by a special, functional coupling.
But there is a nuance, in sports type SUVs instead seamless transmission The circuit transmission of torque is used.
We can say that xDrive is a set of several mechanisms and interaction electronic systems Control. For an example, in addition to the name of the dynamic control system, the DTC thrust control system is additionally used, as well as the help system during HDC descent.
Such systems help xDrive correctly determine and distribute the load on the axis of the car, while fully monitor control without the help of the driver. As is known in such cases, an error may emerge at the slightest human factor, and this will lead to unpredictable consequences.
All these systems are connected with ICM (integral control system chassis Car) and AFS (active steering systems). Thanks to this interaction, the driver will fully feel the dynamics of the car and be confident in each driving movement.
The principle of operation xDrive.
The main task of XDrive can be called good permeability off-road, movement slipping coating, passing steep turns, parking and touching from the spot. This is still not full listwhere XDrive can help, as the automation itself calculates the load on the axis and the distribution of the torque.
As an example, consider somewhat induced situations. Torting from the place, under normal conditions, the clutch will be closed, and the XDrive torque will distribute in the ratio of 40% on the front axle and 60% on the rear axle. Thanks to this distribution, the thrust is evenly distributed throughout the perimeter of the machine. There will also be no slip of the wheels, which means that the tires pass longer. When the car reaches a speed of 20 km / h, XDrive torque will dispense in accordance with the road conditions.
When passing steep turns at speeds, the situation xDRIVE works In proportion to the other, rather than touching. The load will mostly on the front axle. The friction clutch will be closed with greater force, and the torque will be distributed more on the front axis, to bring the car from turn.
The XDRIVE help will include a DSC system dynamic resistance system, which will change the load on the trajectory of the vehicle.
In the situation when driving slipping road XDrive will remove the wheel slip, due to the locking of the friction clutch and when the inter-axis lock is needed using electronics. As a result, the car smoothly will take place obstacles and easily get out of snowdrifts or wetlands.
As for the situation with parking, the whole essence of the XDRIVE system is aimed at relief. Thus, blocking is removed and the car becomes rear-wheel drive, which reduces the load on the steering wheel and the front axle. As a result, the driver will be able to parcerate without effort, and XDRIVE will facilitate this process.
There is no difficulty in using XDRIVE systems at all, as all electronics will solve for you.
Video about the principle of operation of the XDRIVE system:
xDrive is the original system of the intelligent full drive developed by BMW. Despite the fact that this system refers to a permanent full drive, as of its basis, it retains the classical transmission rear-wheel drive scheme for the BMW, i.e. Under normal conditions of movement and condition of the road surface, the car behaves primarily as a rear-wheel drive. But if necessary, part of the torque instantly moves to the front wheels. Thus, the system constantly monitors the state of the vehicle movement, continuously distributing the power between the axes in the optimal ratio. Due to this, the XDRIVE system provides exceptional handling and dynamics when passing turns and motion along with a slippery road.
History of the creation and development of the system
Branded system full bMW drive XDrive was officially represented in 2003. Up to this point, its predecessor was a scheme with a constant distribution of the moment between axes in a fixed ratio. Initially, the four-wheel drive was offered optionally for the rear-wheel drive models of the 3rd and 5th episodes of the 80s. The history of the development and improvement of the BMW full drive systems has four generations.
All-wheel drive model BMW IX325 1985 release
I generation
1985 - a full drive system, distributing torque constantly in a ratio of 37:63 for the front and rear axles, respectively. The rear and inter-axis were rigidly blocked when slipping by viscous couplings, the front differential is free type. It was used on the 325iX model.
II generation
1991 - permanent drive With a ratio of power between axes 36:64, with the possibility of redistribution to any axis to 100% torque. It was carried out using an electromagnetic multi-disc clutch, the rear differential was blocked by a coupling with an electro-hydraulic drive, front - free. In its work, the system took into account the testimony of wheel sensors, the current engine speed and the position of the brake pedal. It was used on the 525IX model.
III generation
1999 - four-wheel drive with constant power distribution in relation to 38:62, all differentials are free with electronic blocking. The system functioned in conjunction with the dynamic course stability system. This scheme of the full drive was applied on the first generation X5 crossover and showed excellent results in both the asphalt movement and in light off-road conditions.
IV generation
2003 - The Intelligent System of Full XDrive Drive was presented in the composition standard equipment The new model X3 and the updated model of the 3rd series E46. To date, XDrive is installed on all models of the X series, optionally - for all other BMW models, except for the 2nd series.
Elements of the system
- In a housing with a multid-sized clutch that performs the function of the inter-axis differential.
- Cardan transmission (front and rear).
- Inter-wheeled differentials (front and rear).
BMW XDrive Full Drive System System Multi-disc friction coupling
Multi-disc friction clutch With servo drive The function of power distribution between the axes is performed located in the dispensing box case with a servomotor drive. Depending on the BMW car model, a chain or gear wheel type can be applied. cardan Transmission Front axis. The coupling is triggered by the command of the control unit and for the fraction of a second changes the ratio of the transmission of torque over the axes.
Principle of operation of the system
For its basis, the XDRIVE system uses a rear-wheel drive transmission scheme. Movement in normal mode provides for the distribution of the torque in the 40:60 ratio (for the front and rear axle). If necessary on the axis with best clutch With the road surface can be transmitted all power potential. XDrive works in coordination with all integrated systems active security, including a system of active steering and a system of coucer-resistant car.
System operation modes
- The beginning of the movement: the differential is blocked, the power between the axes is distributed in the optimal ratio of 40:60, at a speed of over 20 km / h, the ratio of torque is determined by the system based on the current conditions of movement and the road surface.
- Excess turning: When the XDrive system is detected, the signs of the rear axle displacement will outward from the center of rotation high power redirected to the front axle; If necessary, connect dynamic system Currency stability, slowing down the necessary wheels and equalizing the car.
- Insufficient turning: When registering the front axle system from the center of rotation to the rear axle, up to 100% of the torque is fed, and the system of course stability helps, if necessary, stabilize the car.
- Movement on slippery road: Torque is distributed by electronics to the axis with the best clutch of the wheels, preventing slipping.
- Car parking: All power is redirected to the rear axle, facilitating the driver control and reducing the load on the transmission elements.
XDrive system operation scheme Based on the testimony of numerous sensors, the control electronics is capable of recognizing the leakage of the car to care when turning or speeding the clutch loss with the road surface. The system also takes into account the current engine operation parameters, vehicle speed, wheel speed, corner of their rotation and side acceleration of the car. This makes it possible to calculate and share the power balance distributed between the axes as a fraction of a second. The stabilization of the car occurs on the verge of the loss of controllability, while maintaining the force of thrust and dynamics. The system of course stability is included in the work at the last moment in the event that the intelligent four-wheel drive has not coped with the task.
Now the "charged" sedan is officially declassified. Interestingly, the car is though built on the basis, but has an internal index F90, sending to the Bavarian F-models of the last generation. So what do we have?
The main thing is the new sedan became the first passenger "EMCOME" with a full drive. With the increase in the capacity of the capabilities of the canonical rear drive, it became missing, and in the BMW M division after all the same decided to transition to four leading wheels. Transmission M xDrive is structurally the same as "civilian" models of BMW with longitudinal location Engine: Permanent rear drive and a multi-disc coupling of the front wheels. However, all components are enhanced, an active rear M-differential is installed with electronically control, and also added software disabling front driveAs a sedan: in this mode, the machine will retain a traditional rear-wheel character on the joy of enthusiasts and drift lovers.
By default, EMKA has a four-wheel drive, but when translating the stabilization system to the tolerant M Dynamic Mode, which allows slides, the transmission also switches to the 4WD Sport setting with an emphasis on the rear-wheel drive. If the ESP is completely disabled, you can select one of the three drive modes: Standard 4WD, "Relaxed" 4WD Sport and Hooligan 2WD.
From others important changes - Traditional eight-step "automatic", which came to replace the preselative "robot". Modified compared to conventional models the box switches quickly and gently, and the locking of the torque converter is disabled only for the change of gear.
BMW M5 has retained the former Biturbomotor V8 4.4, but it has new turbochargers, increased injection pressure, modified lubrication and cooling systems. Lightweight graduation system - with Helmholtz resonators, which allow you to put the necessary "voice" on high revolutions. Engine power - 600 hp against 560-600 hp For the same model (depending on the version), and the torque is 750 nm instead of 680-700 nm, and the maximum thrust is already available from 1800 rpm.
Compared to the base "five", the extremal sedan has an enlarged kola, the kinematics of the suspension revised, the stabilizers became thicker, and the rubber connections are tougher. M5 is equipped with adaptive shock absorbers with three modes of operation. The same settings and steering mechanism. Basic brakes are composite (cast-iron discs with aluminum hubs): in front - hexpopers with a fixed screw, and behind - simple single-touch with floating bracket. For extra charge - carbon-ceramic discs that reduce unsappressible masses by 23 kg from the machine: such brakes have golden calipers instead of full-time blue.
The former rear-wheel drive "EMKA" in the curb state weighed 1870 kg (without a driver), and the new all-wheel drive is lighter than 15 kg. First of all, this was achieved thanks to a carbonistic roof, which was previously used on models M3, M4 and M6. Front wings, hood, doors and trunk lid - aluminum. And instead lead-acid battery The trunk has a more compact and lightweight lithium-ion battery, with a capacity of only 70 a ∙ h against 105 in the past "EMKI".
What about the dynamics? If the former sedan accelerated to 100 km / h for 4.4 s, and the most forced 600-strong version did it for 3.9 s, then the indicator of the new all-wheel drive car - 3.4 s. The same time at the Mercedes-AMG E 63 S sedan (612 hp), made on the basis of the civilian "five" model (608 hp) makes this exercise for 3.5 s, and universal Audi. RS 6 PERFORMANCE (605 hp) - for 3.7 s. Up to 200 km / h BMW M5 accelerates for 11.1 s, maximum speed Limited (250 km / h), but if you order M "Driver" s Package, then the cut-off will be shifted to 305 km / h.
What else? Extended wings, muscular bumpers, developed system of air intakes and wheels with a diameter of 19 or 20 inches - a common thing for such machines. In the cabin - the M-steering wheel with the red spots of the M1 and M2 buttons, which can be "hanging" individual combinations of the modes of all riding electronics. And the modified selector "Machine" - with a biscuit key with the change of settings on the painter.
World Premiere sedana BMW. M5 will be held in September at the Frankfurt Motor Show. Immediately after that, European dealers will start receiving orders. The price in Germany is already known: from 11,7900 euros - by 4,000 euros less than asking for Mercedes-AMG E 63 S. But the supply of commercial vehicles will begin only by the next spring.
