The BMW “5 Series” gets all-wheel drive and more.
...Somewhere in these parts lives Santa Claus. Signposts with directions to one or another attraction named after the local Santa Claus are found in the vicinity of the Finnish town of Rovaniemi at every step. And here is the Arctic Circle, and in one day I crossed the magical Line of Cold, probably twenty times. In Rovaniemi, it is considered good manners to drive on snowy and icy roads exclusively on studded tires, always give way to snowmobiles and reindeer teams crossing the track, and just in case, unfasten your seat belts when driving on ice crossing. This is how this fertile land of northern Finland looks like in a first approximation. BMW chose him to present the all-wheel drive variant of the “5 Series”, which, at first glance, differs from the standard rear-wheel drive model only by an additional letter “x” in the plate on the trunk lid. Although in reality this sign of an unknown number hides much more ...
ice tango
BUT BEFORE the “five” test organizers allowed us only at the end of the day, offering to first ride on SUVs “BMW X3” and “X5”. They say the 5 Series is just a regular passenger car, and even when equipped with an xDrive all-wheel drive, it won't show you all the benefits of four-wheel drive, unlike cars that were designed for off-road driving from the very beginning.
“Five” with all-wheel drive still retained the typical rear-wheel drive habits.
Therefore, for a good three-quarters of the test drive, I had to plow the snow rut on the “X3”, then master the narrow forest clearings on the “X5” ... in anticipation of the long-awaited moment when we would be allowed to drive a four-wheel drive “five”.
However, having driven a couple of hundred kilometers on BMW SUVs, I was even grateful to the organizers for letting me remember what the main advantage of the Bavarian xDrive all-wheel drive transmission is. And its main advantages are, firstly, in speed, and secondly, in the possibility of the widest variation in torque between the front and rear wheels. Despite the fact that the advantage still remains, as expected real BMW, for rear-wheel drive, in some cases, up to 100% of energy can go to the rear axle. This is felt even during normal driving on snowy roads. Sometimes in a turn from an excess of torque on the rear axle, a noticeable skid begins, which, however, is instantly extinguished by the intervention of the stabilization system and the transfer of traction to the front wheels.
And finally, in front of me is a series of all-wheel drive “fives”. Everything is like a match in the top version of the “BMW 530xi” with a 3-liter 258-horsepower inline “six”. (All-wheel drive can also be combined with a 2.5-liter 6-cylinder engine with 218 horsepower. This model is called the “BMW 525xi”.) In addition, along with the “sedan” body, the all-wheel drive “5 Series” is available as a station wagon. Touring.
By the way, the above-described motors are completely new, and ordinary “fives” can be supplied with them. The power of both engines has increased by almost 30 horsepower, the torque curve now reaches 90% of its peak in almost the entire range of the motor. In addition, both engines can be revved up to higher revs. Thanks to the advanced Valvetronic valve control system, cut-off now occurs at 7,000 rpm, an increase over old motors for 500 revolutions.
However, on the ice of a frozen lake, I will absolutely not care how much the new engines are more powerful or frisky in the set of revolutions. Tires crawling on ice are completely uninteresting at how many “rev / min” the useless slip began.
Engine power has increased by almost 30 forces, and you can “twist” them to higher speeds.
In standby
OUTSIDE all-wheel drive "five" almost do not differ from purely rear-wheel drive cars. With the exception of the wheels, they are already in the basic version of the 17-inch dimension (the usual “fives” have 16 inches as standard). Although... They seem to be a bit taller. Maybe they increased chili here ground clearance? I ask the engineer to come. He explains:
The interior of the all-wheel drive “5 Series” is no different from the interiors of conventional BMWs.
The body is really located 1.5 cm higher than that of the usual “fives”, but the ground clearance remains the same. The increase in height was required to accommodate the all-wheel drive transmission units. At the same time, by the way, we had to radically redesign the design of the transfer case. If on SUVs “X3” and “X5” power is taken to the front wheels through a chain, then on the all-wheel drive “five” a more compact gear transmission is used.
This is not the only compromise. Turning the steering wheel in place, I did not find the presence of the “Active Steering” system, which at low speeds reduces gear ratio steering gear to a meager 1.8 turns. The close layout of the under-engine space forced the designers to abandon the use of a steering wheel with a variable pitch on all-wheel drive vehicles Oh. As well as from the “Dy-namic Drive” system, which helps to deal with rolls in tight turns.
Nevertheless, the “xDrive” all-wheel drive transmission works in a passenger car with the same reliability and predictability as in Bavarian SUVs. The BMW instructor who started ahead of me was driving a conventional rear-wheel drive “530i Touring” station wagon. When starting off in the snow, the stern of his car was slightly led to the side. Immediately, the stabilization system strangled the engine, and only then, having gained traction, the car slowly moved from its place.
For me, on an all-wheel drive car, such a problem could not arise in principle. The “xDrive” system, when starting on any surface, blocks the interaxle multi-plate clutch, and the “five” starts acceleration smoothly and reliably, pushing off the ground (or snow) with all four wheels.
Our “xDrive” system distributes torque across the axles so smoothly and imperceptibly in accordance with data from the sensors of the DSC anti-skid system that you may not even feel at what point the car becomes front or rear wheel drive. Therefore, we have equipped each machine with an additional display, which will display diagrams of the locking of the center clutch. According to them, you can evaluate the degree of torque supply to a particular axis.
The body of the “BMW 530xi” is raised by 1.5 cm, but the ground clearance remains the same.
These words of the organizers came to my mind when my gaze caught on a somewhat rough device that towered over the dashboard. Graphs constantly jumped across his screen, showing the continuous change in torque between the axles. However, while I was driving at a relatively stable speed on a decent road, the car was mostly rear-wheel drive. A very small share of power was supplied to the front axle. But it was worth entering the turn a little more energetically and making the car sway slightly astern, as, under the chirping of the anti-skid system, the degree of blocking of the center differential literally increased to its maximum value in an instant, throwing a solid share of the torque forward, and then returned to its original state. The car stabilized, and I again remembered the words BMW engineers, who told the day before that the speed of the clutch, which controls the distribution of torque between the axles, is a record short time of about one millisecond. For comparison, a modern engine reacts twice as slowly to pressing the gas pedal.
First difference...
APPROACHING to a steep snow-covered descent to a frozen lake, I decided to play it safe and turn on the “Hill Descent Control” system, which is supplied with all modern all-wheel drive BMW. This device, independently slowing down the car, allows you to go down a slippery slope to minimum speed. However, a strange thing, knowing that this system is on my machine, I could not find its key in any way. Maybe, according to the latest fashion, HDC activation was stuffed into the bowels of “iDrive”? And so it turned out. Now hardwired into one of the submenus of this system, the “safe descent from the slope” function can be activated using the rotary joystick controller on the floor tunnel. Or, if you are going to use this mode often (for example, in the Swiss Alps this is a common thing), program it to turn on one of the “free” buttons on the multifunction steering wheel. And you can adjust the speed of descent by pressing the cruise control buttons.
Four-wheel drive it also has a “Touring” variant, that is, a station wagon.
In general, given that the all-wheel drive "five" will obviously be used in heavier and more dangerous road conditions, rather than rear-wheel drive cars, they were endowed with a more sophisticated stability control system. As on BMW SUVs, it is able to take into account the influence of not only the car itself, but also the trailer hanging on its “tail”. In addition, the anti-skid system of all-wheel drive vehicles is capable of performing several more functions: to keep the car on a slope while the driver moves his foot from the brake to the gas, to dry wet pads by pressing them against the brakes for a short time. brake discs, apply additional pressure to brake line when the brakes overheat, and also be always ready for an emergency stop of the car if the driver takes his foot off the gas pedal.
However, I was more interested in the completely opposite perspective, having driven onto a short ring road paved by a bulldozer on a frozen lake, turning off the stabilization system altogether. Moreover, on the all-wheel drive “five”, unlike BMW SUVs this procedure can be done in two stages: first turn off the ABS, allowing the wheels to rotate as much as you like in sliding, and then, holding the shutdown button a little longer, generally deactivate the safety electronics. After all, this is the only way to find out how honestly this car behaves in controlled skid.
Disabling the traction control system, at first I was pleased with the result. The all-wheel drive “5th series” allows you to widely “throw” the car sideways, and only when there is an obvious danger of a turn, the stabilization system comes to the rescue, correcting the car in the right direction by selective braking of the wheels.
But when I deprived myself of this safety net, it turned out that the all-wheel drive “five” with accurate confident taxiing and neat work gas allows you to guide it along the trajectory with jewelry accuracy. Here "xDrive" really anticipates your desires. Here we enter a protracted arc. The car begins to nose out of the turn. We turn the steering wheel, give it a little gas and, having fixed the beginning of the demolition by the slippage of the front wheels, “xDrive” throws the lion's share of the moment back. Now the massive body of the “five” went sideways in a controlled skid. We pull it to exit the turn, reduce the gas, throw the steering wheel again and, as if feeling the need for traction on the front wheels, the car begins to rake in them, confidently pulling itself in the right direction. With all-wheel drive transmission so responsive to your actions, every corner is like dancing with a well-known partner. You are not trying to guess the next step of your partner, but you are 200 percent sure that the next turn will go exactly as you expect. The all-wheel drive “five” is so understandable and predictable in drifts that it is not necessary to expect an unexpected trick from it. It's just a pity that after a few laps along the ring track, the organizers waved their hands, making it clear that enough is enough, clear the way for the next group. The beautiful ice dance ended before reaching the final...
Having carried away the snow extravaganza, I almost forgot to tell you that in addition to the new six-cylinder engines and all-wheel drive transmission, the “5th Series” received some other improvements. Here is a short list of them. Pen parking brake from now on it is always sheathed with genuine leather; the box for small things to the left of the steering wheel has become larger in volume; ordering seats with active adjustment of lateral support depending on the speed and angle of rotation can now be a buyer of any “five”, and not just top versions. In addition, you can program the lift height of the station wagon's rear door using the "iDrive" menu (now you don't have to be afraid that a door that is too high will hit the garage ceiling). Yes, still steering“Servotronic”, which increases force with speed, has moved from options to standard equipment. Although in comparison with the above things, all this, of course, is trifles ...
The “xDrive” transmission works on a passenger car with the same reliability as on Bavarian SUVs.
| Brief technical characteristics “bmw 5 Series” | ||
| 525xi | 530xi | |
| Dimensions, cm | 484.1x184.6x148.2 | |
| Curb weight, kg | 1.665 (1.680)* | 1.665 (1.680) |
| Engine | 6-cyl., in-line, 2.5 l | 6-cyl., in-line, 3 l |
| Power | 218 HP at 6,500 rpm | 258 HP at 6,600 rpm |
| Torque | 250 Nm at 2,750 rpm | 300 Nm at 2,500 rpm | BMW AG
xDrive is the original intelligent all-wheel drive system developed by BMW. Despite the fact that this system belongs to permanent all-wheel drive, at its core it retains the classic rear-wheel drive transmission scheme for BMW, i.e. under normal driving conditions and condition pavement the car behaves predominantly as a rear-wheel drive. But if necessary, part of the torque is instantly transferred to the front wheels. In this way, the system constantly monitors the state of the car's movement, continuously distributing power between the axles in an optimal ratio. As a result, the xDrive system provides exceptional handling and dynamics when cornering and driving on slippery roads.
History of creation and development of the system
Proprietary all-wheel drive system BMW xDrive was officially introduced in 2003. Up to this point, its predecessor was a scheme with a constant distribution of torque between the axles in a fixed ratio. Initially, all-wheel drive was offered as an option for the rear-wheel drive models of the BMW 3 and 5 series of the 80s. The history of the development and improvement of BMW all-wheel drive systems has four generations.
1985 BMW iX325 all-wheel drive model
1st generation
1985 - All-wheel drive system that distributes torque constantly in a ratio of 37:63 for the front and rear axles, respectively. The rear and center differentials were rigidly blocked when slipping by viscous couplings, the front differential was of a free type. Used on the 325iX model.
II generation
1991 - permanent drive with a power ratio between the axles of 36:64, with the possibility of redistribution to any axle up to 100% of the torque. was carried out using an electromagnetic multi-plate clutch, the rear differential was blocked by a clutch with an electro-hydraulic drive, the front one was free. In its work, the system took into account the readings of the wheel speed sensors, the current engine speed and the position of the brake pedal. Used on the 525iX model.
III generation
1999 - four-wheel drive with a constant power distribution in the ratio of 38:62, all differentials are free with electronic locking. The system functioned in conjunction with the dynamic stability control system. This all-wheel drive scheme was used on the first generation X5 crossover and showed excellent results both when driving on asphalt and in conditions light off-road.
IV generation
2003 - The xDrive intelligent all-wheel drive system was introduced as part of the 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.
System elements
- in a housing with a multi-plate clutch that performs the function of an interaxle differential.
- Cardan gears (front and rear).
- Cross-axle differentials (front and rear).
Diagram of the BMW xDrive all-wheel drive system Multi-plate friction clutch
Servo Driven Multi-Disc Friction Clutch The function of power distribution between the axles is performed by a transfer box located in the body and driven by a servomotor. Depending on the model of the BMW car, a chain or gear type of front axle cardan drive can be used. The clutch is activated by the command of the control unit and in a fraction of a second changes the ratio of torque transmission along the axes.
How the system works
At its core, the xDrive system uses a rear-wheel drive transmission scheme. Driving in normal mode provides for a torque distribution in the ratio of 40:60 (for front and rear axles). If necessary, on the axis with better grip with the road surface, the full power potential can be transmitted. xDrive works in concert with all integrated active safety systems, including Active Steering and Vehicle Stability Control.
System operating modes
- Start of movement : differential locked, power between the axles is distributed in an optimal ratio of 40:60, at speeds above 20 km / h, the torque ratio is determined by the system based on current driving conditions and the road surface.
- Oversteer: when the xDrive system detects that the rear axle is moving outward from the pivot point more power redirected to the front axle; connected if necessary dynamic system directional stability, braking the desired wheels and leveling the car.
- Understeer: when the steering system registers the front axle away from the turning center by rear axle up to 100% of torque is applied, and the stability control system helps to stabilize the car if necessary.
- Driving on a slippery road: The torque is distributed electronically to the axle with the best grip, preventing slippage.
- car parking: all power is redirected to the rear axle, making it easier for the driver to control and reducing the load on the transmission elements.
Scheme of the xDrive system Based on the readings of numerous sensors, the control electronics are able to accurately recognize the tendency of the car to drift when cornering or the imminent loss of traction of the wheels with the road surface. The system also takes into account the current parameters of the engine, the speed of the car, the speed of the wheels, the angle of their rotation and the lateral acceleration of the car. This allows you to proactively calculate and change the balance of power distributed between the axles in a fraction of a second. The stabilization of the car occurs on the verge of losing control, while maintaining traction and dynamics. The stability control system is activated at the last moment in the event that the intelligent all-wheel drive has not coped with the task.
xDrive all-wheel drive is now available to buyers of powerful BMW fives. Amazing. And to state this positive fact, it was not at all necessary to go to Finland and ride on the ice of a frozen lake in a BMW 530xi.
But I went. Ride. And I realized that the electronically controlled xDrive is perhaps even more interesting system than the Torsen on the Audi quattro...
Spaghetti, pasta are bad food for racers, Rauno Aaltonen categorically declares at dinner. - Spaghetti makes a person softer. And meat and potatoes are stronger! Well, more salad. That's what I eat. And look, I'm 67 years old and still lead my own snowmobile tours in Finland. Three days, eight hundred kilometers across virgin lands. And there is no one to trust: the youth can not stand it!
Rauno Aaltonen, together with his son Tino, is invited by the BMW people as a "racing taxi driver". Fantastic uncle! He has an opinion on everything. Sometimes undisputed, but their own. And it's worth listening to. After all, Rauno Aaltonen is the man who in the late 60s, together with Paddy Hopkirk and Timo Mäkinen, raced and won the Mini on the slippery serpentines of Monte Carlo. Behind Aaltonen - podiums in rally, in motorcycle racing, in the ring "body" championships, years of methodical work at school driving skills BMW... No wonder sports historians consider it the most versatile of all the great "flying Finns".
Do you know why Finland leads by a huge margin in the number of motorsport world champions? It's genetic. After all, Finnish men are hunters. The lives of their families depended on their speed, endurance, accuracy and composure for centuries!
Aaltonen does not mention the famous Finnish roads: this is obvious. Primers, in winter time ice-covered, wide frozen lakes where you can train all winter without any problems - this is what turned the former cold-blooded hunters into the fastest and most versatile racers on the planet. And now around Rovaniemi - endless white expanses. There is where to roam!
Especially in full drive.
The event organized by the Germans from BMW in subpolar Finland was called the xDrive experience. This is a demonstration of the capabilities of the new proprietary xDrive system, which is now equipped with all BMW all-wheel drive vehicles. The xDrive transmission is very simple - the rear-wheel drive remains constant, like on any BMW, and the front wheels are connected automatically using a simple mechanism. When you look at him, you even take aback - he is so simple. A tiny electric motor that develops only 1 newton meter - even a mixer cannot be turned like this. Behind the motor are two reduction gears, a worm gear and a planetary gear. Then - an eccentric, which, turning, displaces a long lever. And he, in turn, clamps the clutch pack, connecting the drive to the front wheels.
Brilliantly crafted! Energy costs are minimal, the effect is maximum. Why hasn't anyone thought of this before? However, the Valvetronic throttleless intake with its engineering elegance was also first introduced on BMW ...
But here's what's not clear. Initially, any BMW car with the xDrive system is rear-wheel drive. The front-wheel drive is connected electronically without any participation of the driver. For example, during parking maneuvers, the X-drive clutch is completely turned off - the car is strictly rear-wheel drive, since it is not necessary to connect the front now and even harmful. But the “strictly rear” drive mode is activated not only when the car is maneuvering in the yard with low speed and large steering angles, but also after 180 km/h!
On high speed you do not need all-wheel drive, the Bavarians assure. - However, if you "lost" the car on such a move, then if necessary, xDrive will connect the front wheels. But it probably won't help...
What a striking contrast with the ideology of Audi! In Ingolstadt, they have long professed a diametrically opposed religion - four-wheel drive must be permanent and symmetrical. Subaru, Mitsubishi, and all rally cars are built according to the same scheme. WRC cars. And now the Munichers are coming - and turning the world upside down?
Indeed, all 530s with xi nameplates were delivered to Rovaniemi straight from the Swedish BMW winter training ground in Arjeplog. Outside - the usual "fives". Unless the body is planted a little higher, only 15 mm. But the ground clearance remained unchanged. In the cabin - excellent leather seats with active sidewalls, the familiar smell of expensive plastic. And, alas, the same “symmetrical” furniture design of the front panel that annoys me. God, when will all this bangle stuff end...
On top of the panel is an additional display with two linear scales. You don’t have to look at the top: this is a hypothetical “degree of all-wheel drive”. But at the bottom, the actual degree of blocking of the clutch that connects the front is displayed. While I do not touch the gas pedal, the bar at the bottom is empty - the clutch is open. But the very first press on the pedal - and the display instantly comes to life. Electronics proactively, without waiting for starting off, "clamps" xDrive - judging by the display, by about 60% of the maximum, "hard" state. That is, when starting from a standstill, the current BMW 530xi will be similar to previous all-wheel drive Bavarian cars, in which the front wheels were always supplied with less torque than the rear ones.
For what? For the "rear-wheel drive" that is so familiar to BMW drivers!
I turn off the stabilization system by long pressing the DSC button - and with the very first press on the gas I make the "five" in a rear-wheel drive dashingly twist around its axis. Great! Here is the first difference from the "permanent all-wheel drive" Audi, Subaru and Mitsubishi. Those in response to the first addition of gas always first respond as front-wheel drive - they tend to slip out, going into demolition. A BMW with "X-drive" on slippery surface behaves the other way around. The first impulse of the all-wheel drive "five" to add gas is to go into a skid!
But xDrive instantly reacts to the start of a skid - the bar on the display immediately goes dark in its entirety, the clutch is completely blocked, and the BMW momentarily turns into a car with hard all-wheel drive. Here is the second difference from Audi. After all, the Ingolstadt Torsen is not blocked completely, but by 70%, no more. And the X-drive clutch is able to clamp the transmission tightly. Its carrying capacity allows you to apply to the front wheels up to 1500 Nm of torque. Moreover, xDrive is “clamped” completely very quickly, in just one tenth of a second.
I did not expect such a pleasant and predictable behavior from an “automatically-connected-all-wheel drive” car. Processes in the "x-drive" are generally imperceptible. Electronics constantly monitors the situation, flexibly “playing” with the degree of connection of the front end, the column on the display dances all the time, reflecting the activity of the electric motor - somewhere there, under the floor, it rotates wildly back and forth, clamping and loosening the grip of the clutches. But this does not affect the behavior of the car in any way - BMW behaves like a real all-wheel drive. You confidently throw the "five" into wide slides, make it go sideways in an arc under the pull ... And it does everything you want!
Of course, we will still force BMW 530xi and Audi A6 3.0 quattro to fight in a head-to-head battle on ice. But the correspondence difference of the all-wheel drive “five”, as it seemed to me, is a more unambiguous behavior. There is no such first phase when the Audi quattro, under traction with the wheels turned, first slides into a drift - and only then goes into a skid, the direction and angle of which can be controlled by the steering wheel. And in the case of BMW, the demolition phase on ice is simply absent! Immediately - only skidding. Which is no less convenient to manage than on an Audi.
And if the car is turned sideways, if a U-turn seems inevitable, then...
If you feel that you are "losing" the car, slow down! - Rauno Aaltonen in a funny fur hat makes an energetic gesture with his hand. - Only abruptly, by hitting the pedal. For what? Even if the DSC stabilization system is disabled, this will be a signal for it to start action - it will “wake up” for a short time and help stabilize the car. And be sure to try the DTC mode, it's a wonderful thing!
DTC mode, Dynamic Traction Control - this is a kind of "intermediate" stage between the enabled and disabled stabilization system. A short press on the DSC button is enough - and the “five” allows you to slip a little, set a small skid angle, spin all four wheels ... And then, as the situation moves into the phase when only a well-trained person can cope with a skid the driver will gently intervene - and straighten the car.
Moreover, the all-wheel drive "five" is good even with the DSC system turned on - the electronic "collar" here is relatively loose. By the way, electronics xDrive systems and DSC are closely related to each other - the all-wheel drive receives information from all sensors of the stabilization system, which play the role of the "vestibular apparatus". Moreover, according to BMW engineers, software for the "x-drive" it was developed by them independently, it significantly exceeds the engine control algorithms in complexity - and is hardly amenable to chip tuning ...
Electronics! It was she who became the catalyst that helped complete the development of the "rear-wheel drive" BMW concepts. Indeed, since the beginning of the 80s, when they began to work on a transmission for the all-wheel drive BMW 325iX in Munich, BMW engineers wanted to “marry” the advantages of rear and all-wheel drive. But testing all the early all-wheel drive "treshki" with their asymmetric transmission (38% of the moment to the front wheels and 62% to the rear), we always noted - yes, the car is perfectly controlled, but it does not forgive mistakes in driving. And BMW with "x-drive" - forgives!
Moreover, it seemed to me that the all-wheel drive electronics on the “fives” are already more perfect than on the BMW X3 with a similar xDrive system. Anyway, BMW X3 3.0 on the same Finnish ice was less pleasant and obedient in management. For example, on the “x-third” there is no DTC mode, and with the stabilization system turned off, the electronics still sometimes intervened and “bited” the brakes - this was an imitation of differential locks. Yes, and the front-wheel drive was connected not as quickly as on the “fives”.
Of course, these are just first impressions. On gravel, on wet pavement, the BMW xi fifth series may behave differently. Yes, and on ice ... After all, I drove experimental cars - work on debugging the X-drive control has not yet been completed.
In a good way, several programs are needed for such a system, Rauno Aaltonen believes. - For asphalt and ice, for studded and friction winter tires ... But for production car this is, of course, impossible. And colleagues from BMW are now just looking for a single compromise control program for all occasions ...
Yes, now it all depends on the algorithm that will be put into xDrive. So let's wait for serial all-wheel drive sedans and station wagons BMW 525xi and 530xi, which will come to Russia at the end of spring. In Europe, by the way, xDrive will also be installed on the diesel version of the 530xi, but this is not for us.
And by the end of the year, the turn of the third series will come - BMW versions 325xi and 330xi, which will have exactly the same xDrive as on the "fives". It is a pity, of course, that all-wheel drive is the prerogative only expensive cars With powerful motors. Moreover, in Russia we have a price difference between rear wheel drive sedans and their all-wheel drive versions will be more than the €2,500 xDrive surcharge announced in Europe. The reason is simple - if the usual BMW 525i and 530i sedans are assembled in Kaliningrad, then all-wheel drive cars are made only at the "parent" Bavarian plant in Dingolfingen. And the Russian localization of the assembly of all-wheel drive cars at BMW will not be dealt with - it is unprofitable, the volumes are not the same. After all, Russia is not America, where half of all BMW all-wheel drive cars are sold ...
background
BMW has always professed a rear-wheel drive ideology. And only the rally and commercial successes of the Audi Quattro in the early 80s prompted BMW engineers to develop their own all-wheel drive transmission ...
"Treshka" BMW 325iX series E30 appeared in 1985. Its transmission was developed in collaboration with the famous FFD company in accordance with the "Ferguson formula" and differed from the quattro conceptually - the moment from the engine was divided along the axes using the center differential not equally, but in a ratio of 38/62 in favor of the rear wheels. Center and rear differentials were self-locking, with built-in viscous couplings that automatically worked when slipping. All-wheel drive "treshki" were well controlled, but they were noticeably more expensive than usual and did not achieve sports success - differentials with viscous couplings were less durable than the worm Torsen on Audi.
Further all-wheel drive versions alternated. The new “treshka” of the 1991 model (E36) did not have an all-wheel drive version, but in the same 1991, the BMW 525iX sedans and station wagons of the then E34 series picked up the baton. The transmission on the "fives" was also asymmetric (36/64), but much more complex - center differential locks (with electromagnetic drive) and rear (with electro-hydraulic drive) were in charge of electronics. From 1991 to 1996, a little less than 10 thousand all-wheel drive "fives" were produced.
Next shift model ranges again brought castling: the new “five” with the E39 body (1995-2003) did without all-wheel drive, but the previous “three-ruble note” E46 had two all-wheel drive versions - 330Xi and 325Xi. The transmission was also asymmetric (38/62), but this time all the differentials were “open”, and the role of the lock was partially played by the brakes, triggered by the electronics command. The BMW X5 crossover had exactly the same all-wheel drive system before restyling in 2003.
And now all BMW all-wheel drive cars have switched to xDrive - a system without a center differential, but with an automatically connected front end. For the first time, xDrive debuted on the X3 crossover, then migrated to the X5, and now it will be equipped with fives and new threes with the xi nameplate.
Now the “charged” sedan has been declassified officially. It is interesting that the car, although built on the basis, has an internal F90 index, referring to the Bavarian F-models of the previous generation. So what do we have?
Main - new sedan became the first passenger car with all-wheel drive. With the increase in power, the capabilities of the canonical rear-wheel drive began to be lacking, and in the BMW M division they nevertheless decided to switch to four-wheel drive. The M xDrive transmission is structurally the same as in the BMW civilian models with a longitudinal engine: constant rear drive and a multi-plate clutch for connecting the front wheels. However, all components are reinforced, an active rear M-differential With electronic control, and added a software option to disable front wheel drive, like a sedan: in this mode, the car will retain its traditional rear-wheel drive character to the delight of enthusiasts and drifters.
By default, the emka has all-wheel drive, but when the stabilization system is switched to the tolerant M Dynamic Mode, which allows slips, the transmission also switches to the 4WD Sport setting with an emphasis on rear-wheel drive. If ESP is completely disabled, then you can choose one of three drive modes: standard 4WD, "relaxed" 4WD Sport and hooligan 2WD.
Other important changes include the traditional eight-speed "automatic", which replaced the preselective "robot". Improved compared to conventional models, the gearbox shifts quickly and smoothly, and the torque converter lock-up is disabled only during gear changes.
The BMW M5 retained the old V8 4.4 biturbo engine, but it has new turbochargers, increased injection pressure, modified lubrication and cooling systems. Lightweight exhaust system- with Helmholtz resonators, which allow you to put the desired "voice" at high speeds. Engine power - 600 hp against 560-600 hp in the previous model (depending on the version), and the torque is 750 Nm instead of 680-700 Nm, with maximum traction already available from 1800 rpm.
Compared to the base “five”, the extreme sedan has an increased track, the kinematics of the suspension has been revised, the stabilizers have become thicker, and the rubber joints are tougher. M5 equipped with adaptive dampers with three modes of operation. The same number of settings and the steering mechanism. Base brakes are compound (cast iron discs with aluminum hubs): in front - six-piston with a fixed bracket, and in the back - simple single-piston with a floating bracket. For a surcharge - carbon-ceramic discs, which reduce unsprung masses 23 kg from the car: these brakes have golden calipers instead of the regular blue ones.
The old rear-wheel drive "emka" in running order weighed 1870 kg (without a driver), and the new all-wheel drive is 15 kg lighter. First of all, this was achieved thanks to the carbon fiber roof, which was previously used on the M3, M4 and M6 models. The front fenders, hood, doors and trunk lid are aluminum. And instead lead acid battery a more compact and lighter lithium-ion battery is installed in the trunk, and with a capacity of only 70 Ah versus 105 for the previous emka.
What about dynamics? If the old sedan accelerated to 100 km / h in 4.4 seconds, and the most forced 600-horsepower version did it in 3.9 seconds, then the indicator of the new all-wheel drive car is 3.4 seconds. The Mercedes-AMG E 63 S sedan (612 hp) has the same time, the model (608 hp) made on the basis of the civilian “five” does this exercise in 3.5 s, and the Audi RS 6 performance station wagon ( 605 hp) - in 3.7 s. Up to 200 km / h BMW M5 accelerates in 11.1 s, maximum speed limited (250 km / h), but if you order the M "Driver" s Package, then the cut-off will be shifted to 305 km / h.
What else? Flared fenders, muscular bumpers, an advanced air intake system and 19 or 20 inch wheels are commonplace for such machines. Inside, there is an M-steering wheel with red spots on the M1 and M2 buttons, on which you can “hang” individual combinations of modes for all driving electronics. And the modified selector of the "machine" - with a two-armed key for changing settings on the top.
world premiere BMW sedan The M5 will take place in September at the Frankfurt Motor Show. Immediately after that, European dealers will start accepting orders. The price in Germany is already known: from 117,900 euros - 4,000 euros less than they ask for the Mercedes-AMG E 63 S. But deliveries of commercial vehicles will begin only next spring.
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 they forgot how to use the system, and it quickly broke down. But still, those who used BWM cars without xDrive and with this system stated that the difference in driving was significant.
Second generation
Start 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. center differential blocked by 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. Torque distribution on the axle at normal driving became 62% on the rear and 38% on the front axle, and the inter-wheel and inter-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, allocate last generation xdrive systems. 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 electronic control. 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 brand bmw they say that thanks to such an xDrive system, cars with good cross-country ability, directional stability, and as a result, improved safety.
The xDrive system is used for BMW vehicles with a rear-wheel drive transmission. The torque is distributed between the axles thanks to transfer box. 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 SUVs sports type instead of gear train torque chain is used.
We can say that xDrive is a set of several mechanisms and interaction electronic systems management. 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 with the help of ICM (integrated control system undercarriage vehicle) and AFS (active steering systems). 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 taking sharp turns at speed, the situation work xDrive proportionally different than starting off. 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.
IN xdrive help dynamic exchange rate system will be enabled sustainability DSC, which, due to the braking of the wheels, will change the load on the trajectory of the car.
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:
