xDrive - the inscription on BMW cars is put for a reason or some small addition, this is the first indicator of a difficult drive in a car. Consider the principle of operation and the 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 to be safe while driving. Such aspects are taken into account by BMW engineers in the first place when developing a new model.
The inscription xDrive on the front fender of a BMW car is not casual, it is not a minor tuning or some specific addition. Such an inscription indicates that all-wheel drive is installed in the BMW.
The beginning of the existence of the xDrive system
BMW car specialists distinguish 4 generations. Rumor has it that in 2017, engineers want to introduce a new generation of all-wheel drive.
First generation
The xDrive all-wheel drive system dates back to 1985. The torque was distributed according to the principle: 63% was allocated to the rear axle and 37% to the front axle. The composition of such an all-wheel drive included a locking of the center and rear wheel differentials with the help of a viscous clutch.
It often happened that inexperienced drivers forgot the principle of using the system, and it quickly failed. But still, those who used BWM cars without xDrive and with this system stated that the difference in driving was significant.
Second generation
The beginning of the second generation xDrive falls on 1991. This time the distribution has changed a little, now 36% fell on the front axle and 64% on the rear wheels. The center differential is locked using a multi-plate clutch on electromagnetic control. The rear cross-axle differential is locked using a multi-plate clutch based on electro-hydraulics. Thanks to this innovation, it was possible to redistribute the torque between the axles in any ratio from 0% to 100%.
Many motorists say that it was from this generation that many BMW cars began to be equipped with the xDrive system. Yes, and driving a car with such a system has become pleasant and safe. At one time, these machines began to be in great demand and quickly gained a positive reputation.
third generation
1999 was the beginning of the third generation xDrive. The distribution of torque on the axle during normal driving became 62% on the rear and 38% on the front axle, and the axle and axle differentials became free. Blocking of cross-axle differentials is carried out electronically, and a system of dynamic control of the vehicle's course stability appears to help with all-wheel drive.
fourth generation
In 2003, the latest generation of the xDrive system is released. Torque is distributed in a ratio of 60% to the rear axle and 40% to the front axle of the BMW. The center differential is carried out using a multi-plate friction clutch, and controlled electronically. Torque distribution is still possible from 0 to 100%. The cross-axle differential lock is electronic, due to which it interacts with the vehicle's Dynamic Stability Control (DSC) system.
Fans of the BMW brand say that thanks to such an xDrive system, cars have appeared with good cross-country ability, directional stability, and as a result, safety has improved.
The xDrive system is used for BMW vehicles with a rear-wheel drive transmission. Torque is distributed between the axles thanks to the transfer case. From itself, it represents a gear train on the front axle, which is controlled by a special, functional clutch.
But there is a nuance, in sports-type SUVs, instead of a gear, a torque chain is used.
We can say that xDrive is a set of several mechanisms and the interaction of electronic control systems. For example, in addition to the already named dynamic stability control system, the DTC traction control system is additionally used, as well as the HDC descent assistance system.
Such systems help xDrive correctly determine and distribute the load on the axles of the car, while maintaining full control without driver assistance. As you know, in such cases, at the slightest human factor, an error can pop up, and this can lead to unpredictable consequences.
All these systems are interconnected using ICM (Integral Vehicle Chassis Management) and AFS (Active Steering). Thanks to this interaction, the driver will fully feel the dynamics of the car and be confident in every movement of the steering wheel.
How xDrive works
The main task of xDrive can be called good off-road traction, driving on slippery surfaces, passing sharp turns, parking and starting off. This is not yet a complete list where xDrive can help, as the automation itself calculates the axle load and torque distribution.
As an example, consider a few induced situations. Starting off, under normal conditions, the clutch will be closed and the xDrive torque will be distributed in a ratio of 40% to the front axle and 60% to the rear axle. Thanks to this distribution, the thrust is evenly distributed around the entire perimeter of the machine. There will also be no wheel slip, which means that tires last longer. When the car reaches a speed of 20 km / h, xDrive torque will distribute according to road conditions.
When going through tight corners at speed, the xDrive situation is proportionately different than pulling away. The load will be on the front axle to a greater extent. The friction clutch will close with more force, and the torque will be distributed more to the front axle to get the car out of the turn.
To help xDrive, the DSC Dynamic Stability Program will be included, which, due to the braking of the wheels, will change the load on the vehicle's trajectory.
In a situation when driving on a slippery road, xDrive will remove wheel slip, thanks to a friction clutch lock and, if necessary, an electronic center lock. As a result, the car will smoothly pass obstacles and easily get out of snowdrifts or wetlands.
As for the parking situation, the whole point of the xDrive system is aimed at facilitating. Thus, the lock is removed and the car becomes rear-wheel drive, which reduces the load on the steering wheel and front axle. As a result, the driver will be able to park effortlessly, and xDrive will facilitate this process.
There is no difficulty in using new generation xDrive systems at all, since all electronics will decide for you.
Video about the principle of operation of the xDrive system:
The basis of safe and enjoyable driving is the most complete control of the forces acting on the car. Driving safety is the most important aspect taken into account in the process of creating a running system, as well as a drive system for BMW vehicles.
The influence of dynamic forces (whether vertical, transverse or longitudinal) can be tamed in various ways, which include:
- skillful steering;
- gentle braking;
- speed and sensitivity of actuation of shock absorbers and a system of elastic elements.
Following all of the above factors allows you to maximize driving safety and get maximum satisfaction even from sports driving on disgusting road surfaces.
Why do you need all-wheel drive?
Initially, all-wheel drive versions of BMW were designed to determine the most acceptable parameters of tractive force and the ability to maintain the original state under various influences characteristic of movement. Only 25 years later, the engineered BMW xDrive all-wheel drive system was able to make this mission a reality, and on a scale that is unparalleled anywhere in the world. This intelligent system, due to its fast response, variability and accuracy, has the ability to adjust the force in cases where it is converted into motion dynamics. This technology was developed in such a way as to apply to the maximum all the advantages of the distribution of force among the four wheels and get rid of or at least reduce the characteristic disadvantages.
In the ingrained understanding, the all-wheel drive system is aimed at improving traction when driving on country roads or slippery roads. At the same time, one has to face some flaws arising from the inefficient distribution of efforts, which can be expressed in: unsatisfactory qualities of the running gear; in limiting the susceptibility of the steering wheel to turns when driving at high speeds; in the lack of comfort when performing various maneuvers. All these shortcomings draw attention to themselves very much, especially when compared with the rear-wheel drive system characteristic of BMW.
In the process of creating the first all-wheel drive, the designers of BMW were able to perfectly combine the advantages of the already proven rear-wheel drive and all-wheel drive system.
More dynamic cornering – more safety in winter
Of note is 1985, when the BMW 325iX was shown at the Frankfurt Motor Show (IAA). In this model, the main principle of all-wheel drive was clearly traced: more dynamics in corners leads to less danger in winter. The main distinguishing feature that distinguishes this car from others like it is the unusual distribution of force between the wheels. Instead of the usual equal distribution of weight, the German company proposed an option where, when driving, 63% of the torque falls on the rear axle, and 37% on the front axle. This made it possible to maintain the exact execution of turns.
The rear axle wheel drive contains viscous blocking elements, which, in the event 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 axle. Despite the fact that the regulation of the locks occurred automatically, the anti-lock mechanism was always in working order. In practice, this concept worked in conditions where the car could show all its advantages:
- when accelerating out of corners, the traction force was optimized;
- in the period of a jerk on a wet road surface, the transfer of force occurred without slipping;
- when moving on ice and snow, safe driving performance was ensured.
The need for electronic control of the distribution of efforts
The developed electronic control systems have opened up new possibilities for optimizing traction, dynamics and stability during the movement of all-wheel drive vehicles.
In 1991, the next BMW 525ix model was introduced, in which, when diagnosing the current condition, the electronic system took into account the wheel speed information received from the anti-lock mechanism, data on the position of the throttle valve of the engine and the state of the brake system.
The distribution of the drive torque during normal driving in the ratio of 36% to the front axle and 64% to the rear was provided by a multi-plate clutch, adjustable continuously variable and located in the transfer case. This electro-hydraulic clutch, in order to avoid situations with the rotation of each individual wheel, regulated the power flow that occurs in the final drive of the rear axle. The combination with the front axle was due to the power take-off device. With the help of a cardan shaft, the rear axle differential was attached.
The transfer case was blocked electromagnetically, so even in difficult conditions, driving stability was automatically ensured. For acceleration on both flat and unpaved roads, there was always enough traction due to the adjustable locks.
In 1999, the BMW X5 also introduced all-wheel drive, which led to an improvement in the distribution of forces through electronic control. This model was the first in the category of sports cars SAV (Sports Activity Vehicle), in which the torque was distributed in the following ratio: 38% to the front wheels and 62% to the rear.
In the global version, a free center differential controlled the power flow among the front and rear wheels. Brake control action (individual for each wheel) provided the necessary blocking for stability during movement and optimization of traction.
The BMW X5 also contained:
- automatic brake mechanism (ADB-X);
- dynamic stability control (DSC);
- descent speed control (HDC).
The combination of all of the above characteristics made the car suitable not only for sports driving, but for driving on a road surface that is far from perfect.
BMW xDrive intelligent all-wheel drive: quick, precise, ahead
In 2003, the BMW X3 model was introduced, with which the use of a new generation of all-wheel drive systems began. In parallel with this car, all-wheel drive began to be used in the BMW X5. In this BMW xDrive system, the variable distribution of torque between the front and rear wheels has been preserved due to the electronic multi-plate clutch with longitudinal locking. This clutch function was provided by the Dynamic Stability Control (DSC) system, whereby the xDrive system defined new limits for the accuracy and speed of distribution of drive torques determined by the situation. In addition, this system confirmed the status of "intelligent all-wheel drive", as it became possible to pre-determine the risk of slipping of the drive wheels and counteract this through the distribution of forces.
The continuous development of xDrive has thus far optimized traction, driving stability in poor road conditions and cornering dynamics. This system is used with the same success for BMW 3, 5, 7 series models.
Improve agility and optimize cornering dynamics with new xDrive and DSC tuning methods
For vehicles with all-wheel drive, currently equipped with xDrive, it is possible to adjust the optimization of dynamics, which is especially noticeable, as a rule, when cornering. The turning force is mainly directed to the rear axle to improve maneuverability. When exiting a turn, in order to make the traction force as optimal as possible, the original percentage ratio between the front and rear axles, which is 40:60, is restored. The electronic driving dynamics control contributes to a gradual effect on the braking and also ensures the stabilization of the drive torque. Thanks to the same system, under various circumstances, resistance to understeer becomes possible and effective.
The xDrive and DSC control electronics, in the event of a strong outward protrusion of the front wheels, specifically brake the rear wheel located closest to the center of the turn. As a result, traction power is lost, but at the same time, this loss is compensated by an increase in drive power.
Dynamic Performance Control - the highest precision in the distribution of forces
The combination of BMW xDrive and Dynamic Performance Control significantly increases the possibility of optimizing traction and driving stability in the most efficient way. Dynamic Performance Control is available on the BMW X6 , X5 M and X6 M because there is a differential power distribution between the right and left rear wheels.
Thanks to this torque distribution, the entire speed range is accompanied by optimal steering response and lateral stability. When oversteering, xDrive redistributes power to reduce drive torque at the rear wheels, while Dynamic Performance Control reduces power to the most heavily loaded rear wheel by shifting it to the rear wheel closer to the center of the turn. In the event of understeer, these systems operate in the opposite way.
The stabilizing effect of Dynamic Performance Control is evident even when the driver releases the accelerator while moving. Special devices located in the main gear of the rear axle contribute to the variable distribution of force both in a situation of a sharp change in load and in forced idling.
Video test drive all-wheel drive BMW e34
All the cons of the BMW 5-Series (F10) 2016-2017
➖ High track sensitivity
➖ Closely in the back row
➖ Problem rain sensor
pros
➕ Dynamics
➕ Comfortable interior
➕ Handling (on good roads)
➕ Economy
The advantages and disadvantages of the BMW 5-Series 2016-2017 are identified based on feedback from real owners. More detailed pros and cons of the BMW 5-Series (F10) with automatic, rear-wheel drive and xDrive all-wheel drive can be found in the stories below:
Owner reviews
Crack of front cv joints (56,000 km) - replacement under warranty. Crack again at 78,000 km, but the warranty is over - the price is 110,000 rubles. It still runs on crackling ones - 143,000 km. Bottom protection - roofing material! Changed, but also torn to tatters. Otherwise, consumption, traction, comfort, handling — excellent.
Review of BMW 5-Series 2.0d (218 HP) AT AWD 2013
Video review
The dynamics are excellent - it accelerates to 100 km / h in 6.5 s. The gasoline engine is not very voracious. I think that 9-10 liters per 100 km on the highway and 12 liters in the city for an all-wheel drive car with a 245-horsepower engine is a very good indicator.
On winter roads, four-wheel drive often helps out. In general, the BMW 528 is well suited for winter operation: the engine warms up quickly, there is a heated steering wheel and front seats.
BMW is a cool car! I really like the strict design, but at the same time comfortable interior. Noise isolation is better than that of the Mercedes-Benz C-class, which also managed to drive a little.
Among the shortcomings of BMW, I note a small ground clearance, and the car reacts very nervously to ruts, so you have to taxi on rough roads. The rain sensor lives its own life, it can easily turn on the wipers on dry glass.
Dmitry, review of the BMW 5-Series F10 2.0 (245 hp) xDrive 2014
I had a chance to drive an Audi A6 3.0d in Europe and have the opportunity to compare. Drive compared to competitors for BMW! It feels like a BeHa with a 2.0 engine outperforms the A6 3.0 due to the latter’s stupid machine, as well as the gas pedal delay, which generally eats up all the driving sensations. BMW is a rocket acceleration and a complete sense of control over the situation, so the leader here is obvious.
Ergonomics and comfort. In terms of soundproofing, the Audi A6 wins, as the wheels on the BMW make a dumb noise, and the engine makes noise at low speed. Ergonomics for BMW is beyond competition. Very handy speed limiter and cruise control.
Of the minuses of BMW, I can note: a dull rain sensor, weak Shumkov, no sound system (changed to Harman) … and probably everything!
Of the benefits: dynamics and drive, ergonomics, low consumption of diesel fuel, interior design.
Igor Novomirsky, review about BMW 5-series 2.0d (184 hp) automatic transmission 2015
We have a basic motor, we, like everyone who wrote reviews, thought that a kopeck piece would somehow pull. But he falls! No, even heaps!!! He's crazy! Even if somewhere the gasoline is bad, the “sport” button will always help out.
Overtaking takes just easily, the engine turns up to 180 km / h quietly. Brakes… Wow those brakes!!! Friend, do you need to stop? Yes, no questions! Easily! That's how the machine answers me! Our gentleman eats very little. In total, 8.5-9 on the highway (I drive aggressively) with SUCH dynamics!
They write that Run Flat tires are tough, but for me it’s very cool. Rut - I don’t notice it ... Pits and bumps - I didn’t hear it either ... Water in the rut? Yes, okay!
Ruslan Zaitsev, review of BMW 5-Series (F10) 2.0 (184 hp) with automatic 2015
Now almost 80 thousand on the odometer, and everything is OK, the car pleases, I love her very much and she still brings me pleasure! Managed to do 8 MOT and 2 warranty repairs. The average cost of maintenance is about 15-20 thousand, plus pads and brake discs. This is probably not the money to say that this car is expensive to maintain. And now for the car as a whole:
1. Ergonomics is just fine. Landing behind the wheel in a buzz. It is easy to choose the settings for yourself (unless you are a giant or a dwarf). Of the minuses: I noticed that the right leg goes numb during long trains (from 400-500 km). I can not connect with the seat, most likely due to my incorrect fit.
2. Average capacity. For a family man, which I am, there is not enough space. The rear seats are more for children. Trunk for two large bags and one small. The stroller is only included in the analysis.
3. Management is excellent. Although in the past Mazda 6 also liked it.
4. Comfortable suspension. Golden mean. Not hard and not rolly. I drive 18″.
5. The build quality is good. I don't see any bugs. In addition to the plastic lining at the gearbox, everything is scratched after 20 thousand. Materials are good quality and pleasant. By 80 thousand, the door card was rubbed in the grip of the handle. I sin on the ring.
6. Profitability. It's just a fly. In this question 5+. Track 6-8 liters (depending on speed). The city is stable 10 liters, no matter how hard you drive. The record so far is 1,008 km on one tank. This is a track at a speed of 120-150 km / h. On average, a tank in the city is enough for 600 km.
7. Dynamics. Here you can argue for a long time. Diesel pulls like a locomotive. Up to 100 km / h you feel comfortable both in the city and on the highway. After 100 km/h maneuvers are harder, but not bad enough.
8. Appearance is super. Paintwork in white with a bang. Although the BMW should be black, white does not harm it.
Review of the BMW 5-Series 520d (190 hp) automatic transmission 2016
Ergonomics of the driver's seat at 5+. Everything is in its place, everything is conveniently pressed and spinning. Rulitsya and brakes are also very good, but very sensitive to the rut. Perhaps because of the different-wide front and rear wheels of the 18th radius, or Run Flat rubber.
Acceleration is confident, but not a rocket: 8 seconds to 100 km / h. Since it is unprofitable to accelerate more than 80-100 km / h in Moscow, the 2.0D dynamics are quite enough for the city.
Headlights are LED with a turn function, but, damn it, very expensive. Pasted on them a film from stones. The sound of a diesel engine is heard only during acceleration, but it does not bother me, but even makes me happy. Internet access and voice control are available. With a Xiaomi smartphone, the multimedia system legalized without problems.
In the "five" there is very little space for things in the armrest and there really is no place to attach a smartphone. It does not fit in the ashtray and cup holder, so it lies on the passenger seat during charging. I also note the not always adequate operation of the rain sensor.
The rear passengers are cramped. In addition to deflectors and a cigarette lighter, there is nothing at the back, but this is such a complete set. Since I drive alone most of the time, I don't care.
Review of BMW 5-series 2.0 diesel (190 hp) automatic transmission 2016
