Four-wheel drive: principle of operation, systems and technologies. Which drive is fuller? We understand the types of all-wheel drive transmissions What is all-wheel drive in a car

19.06.2019

The design of the transmission of an all-wheel drive vehicle provides for the possibility of transmitting torque to all four wheels. Various schemes allow you to realize the full potential of the power, handling and active safety of the car, depending on its purpose. All-wheel drive transmission may be abbreviated as 4x4, 4wd or AWD.

Advantages of all-wheel drive

The advantages of a car equipped with an all-wheel drive transmission are easy to understand based on the disadvantages of a two-wheel drive car, in which the drive is carried out only on one axle (front or rear), i.e. the drive wheels are either front or rear.

All-wheel drive off-road vehicle

Application of free on the bulk budget cars in difficult road conditions, it actually makes one wheel drive, which has the worst grip on the road surface. This is a feature of the differential. And even if both wheels have sufficient traction, too much power often results in wheel spin, loss of control, or vehicle stall. These are the disadvantages of a monodrive, which are especially visible on slippery road surfaces and off-road. In order to eliminate these shortcomings, manufacturers use self-locking cross-axle differentials.

However, the best solution is to make all wheels drive, improving and supplementing the transmission design with the necessary components. Four-wheel drive provides the car the following benefits:

increased permeability;
improved grip when starting on slippery surfaces;
directional stability and predictable behavior on slippery roads.

All-wheel drive transmission elements

All-wheel drive transmission

The all-wheel drive transmission of a car consists of the following main elements:

manual or automatic transmission;
transfer case or multi-plate clutch;
center differential;
cardan transmission;
rear and front differentials;
controls.

Types of all-wheel drive

Permanent four-wheel drive

Constant four-wheel drive 4x4 - a type of drive in which torque is distributed from the engine simultaneously to all wheels. Such a drive can be used on different classes of vehicles with a longitudinal or transverse engine layout. For optimal torque distribution modern systems all-wheel drive are equipped with self-locking differentials with the possibility of distributing power along the axles in different ratios.

Elements of permanent all-wheel drive system Quattro

Electronics coordinates the operation of the system, receiving signals from wheel speed sensors, and instantly changes the power ratio depending on road conditions and the nature of the movement. This type of all-wheel drive is the most advanced system that provides the best active safety and driving dynamics.

Disadvantages: increased fuel consumption and a constant load on the transmission elements.

Branded permanent all-wheel drive is used in their cars by manufacturers such as Audi (), BMW (), Mercedes () and others.

force connected

For cross-country vehicles best way implementation of all-wheel drive - forcibly connected. It is arranged according to the standard scheme, only the central differential is missing. The driving axle is the rear, the connected axle is the front. Torque is transmitted to the front axle through a manually operated transfer case.

Scheme and elements of the connected all-wheel drive

The driver independently turns on the drive of all wheels by means of levers or control buttons before overcoming difficult area or, for example, off-road. The inclusion of a transfer case provides a rigid connection between the axles and the distribution of torque in an equal ratio. The 4WD indicator lights up on the instrument panel. Often, the design additionally provides for the possibility of hard blocking of interwheel differentials, as well as the use of high and low gears.

When all-wheel drive is on, the transmission elements are under heavy loads, the vehicle's handling is significantly deteriorating. IN normal conditions the drive is turned off and the four-wheel drive indicator goes out, the movement continues with the rear driven axle. The transmission is released, which ensures the extension of its service life and reduced fuel consumption. Forced all-wheel drive is used mainly on SUVs. For example, on Toyota Land Cruiser and Land Rover Defender.

Automatic connection

Scheme of automatically connected all-wheel drive

The scheme of the automatically connected all-wheel drive is designed taking into account the possibility of instantly connecting the second axle to the leading one. The main drive is rear or front. When fixing the difference in rotation of the wheels, the friction clutch of the center differential closes at the command of the electronics, and power begins to be transmitted to all wheels. A number of models provide a switchable 4x4 mode, and the car becomes a monodrive. The automatically connected 4Motion all-wheel drive system is used on Volkswagen models.

Application of various all-wheel drive systems

Depending on the class and purpose of vehicles, various types of all-wheel drive are used, which are most suitable in terms of their performance and performance.

For premium cars, where, first of all, comfort, handling and safety matter, the best option is permanent all-wheel drive under the control of control electronics. Luxury SUVs combine permanent all-wheel drive and forced all-wheel drive with the possibility of hard-locking differentials. The operation of the all-wheel drive system is controlled and regulated by electronics. If necessary, the driver includes a hard lock if, for example, you need to leave the mud.

March 14, 2017, 00:54

If a decade and a half ago, the owner of an all-wheel drive car was considered an almost unconditional conqueror of roads, then recently, when talking about all-wheel drive of a car, motorists, as a rule, use a clarifying wording, speaking of “full-fledged all-wheel drive”.

Any car enthusiast will say that for storming a yard littered with snow, or when overcoming a primer washed out by rains to a summer residence, a car with a 4x4 wheel arrangement would be ideal. And when driving on an asphalt road in a slippery rainy autumn season, a driver who is driving an all-wheel drive car will feel much more confident. However, already a few meters after the snow-covered section of the road is overcome, or the car gets out of the broken primer onto the asphalt road, the additional drive axle will only cause a serious waste of fuel.

The advantages of all-wheel drive vehicles are obvious - such cars are less sensitive and whimsical to the quality of the coating under the wheels, when driving off a paved road, an all-wheel drive car will be able to confidently deliver the driver and passengers to their destination, and on a wet or icy highway such a car will retain decent dynamics and controllability.

In an attempt to maintain the benefits of all-wheel drive without compromising the vehicle's fuel efficiency, most modern automakers are turning to electronic systems, working in conjunction with multi-plate clutches capable of connecting the second wheel axle to automatic mode only if necessary.

Classification of all-wheel drive systems

Among specialists, it is customary to distinguish three types of all-wheel drive systems:

Non-switchable permanent (full-time or 4WD);
Electronically connected (torque on-demand or AWD);
In addition, there are all-wheel drive systems with the possibility of manual connection (part-time).

The all-wheel drive transmission, which was the first to be mass-installed on mass-produced cars, is considered the part-time system. Such a system is a device that rigidly connects the front axle. As a result, the wheels of both axles are forced to rotate at the same speed. Naturally, about installing the center differential in this case speech is not.

Differential - what is it?

Considering such a device as a differential, it should be borne in mind that this is a special mechanical device that receives traction from the drive shaft and distributes it in the required proportion along the drive wheels. In this case, the difference in wheel speed is compensated automatically. Thus, through the differential, the torque is directed to the drive wheels, and the wheels themselves will have different (differentiated) angular speeds.

Differentials can be applied to both axles of a vehicle equipped with an all-wheel drive transmission. Individual models equipped with a differential that is mounted in - such an all-wheel drive solution is usually classified as a "full-time" system.

To understand why a car needs a differential, it is worth understanding the principle of its operation. The thing is that the wheels of any car have the same speed of rotation only when it moves in the forward direction. As soon as the car begins to turn, each of the four wheels acquires an individual speed, despite the fact that both axles begin to “compete” in speed with each other. The explanation for this phenomenon will be the occurrence of its own trajectory for each of the wheels - those that are inside the turn pass a shorter distance compared to the outer wheel.

Thus, if there were no differential, in a corner the inner wheel would turn in place to compensate for the rotation of the outer wheel. In such conditions, driving at high speed would be impossible, and there would be no need to talk about the controllability of the car. The presence of a differential makes it possible for the axles to “overtake” each other in the right way when a difference in the speeds of the wheels occurs.

Cross-axle differential device - when entering a turn, it allows the inner wheel to spin more slowly

part-time system

The part-time system is designed without installing a center differential. Such a device involves the transfer of torque from a running engine to both axles in the same amount - thus, both axles rotate with equal speed. Obviously, for cars equipped with a part-time drive system, driving on roads with good asphalt or concrete pavement is contraindicated, because when trying to make a turn, the driver provokes the above-described difference in the length of the bridges.

Since the moment is transmitted along the axes in a ratio of 50 to 50, when the steering wheel is turned, the wheels of one of the axles will slip. If there is snow, mud or sand under the wheels of the car (which often happens when traveling to the country, a picnic or fishing), then a slight adhesion of the wheels and the road surface will practically not cause any harm to the car. But in the case of maneuvers on a dry and hard road surface, the slippage that occurs negatively affects the functioning of the transmission, causes accelerated tire wear, and also reduces the quality of vehicle handling.

Thus, vehicles equipped with a plug-in all-wheel drive system are good for regular use in conditions bad roads or to conquer off-road. In this case, interlocks are generally not required, since one bridge will initially be hard-wired.

Other advantages of the part-time all-wheel drive solution are the relative reliability and simplicity of the whole design: there are no electrical or mechanical drives, no locks are used, no differentials are applied. Simplifies the system and the fact that it does not have additional hydraulic or pneumatic elements. However, for daily operation such a system is inconvenient. The use of a constantly switched on axle of the front wheels is fraught with a breakdown of the car, and constantly turning the axle on and off is simply inconvenient. The list of car models, the design of which provides for the use of part-time, includes the following makes and models of vehicles: Nissan Patrol of the first generations, pickup truck, Nissan NP300, Jeep Wrangler and domestic.

Permanent four-wheel drive

The listed features and disadvantages of the plug-in all-wheel drive system led to the development of a permanently connected all-wheel drive system, free from such problems. As a result, cars with a “4WD” drive saw the light, in which all available wheels play the role of the leading wheels, and there is also a free center differential that allows you to produce “unnecessary” power due to the slippage of one of the gear satellites. Thus, the car always moves with all driving wheels.

The nuance of the 4WD mechanism is its following feature. When a wheel slips, the cross-axle differential disables the second wheel of this axle. The second pair of wheels works in a similar way. It is quite possible that a car with a 4WD drive system, having slipped the wheels of both axles at the same time, is completely immobilized. To minimize the drop in off-road properties of all-wheel drive vehicles with a 4WD system, developers install at least one forced-type lock. As a rule, the center differential is forcibly blocked.

As an additional option, they often offer the installation of a front differential lock. Car models with a 4WD system include SUVs such as: Land Cruiser 100 Prado and Land Cruiser 100, and. But perhaps the most famous model equipped with a 4WD drive is.

Despite all its advantages, the permanently connected all-wheel drive system, unfortunately, has certain disadvantages. So, in terms of handling on asphalt and other hard roads, SUVs with both leading axles are quite far from ideal. In critical situations, such a car will try to slip out of the turn, not responding to the rotation of the steering wheel and pressing the gas pedal properly.

Plug-in all-wheel drive (automatic)

The modern format of crossovers, regardless of the size of the car, implies the ability to quickly and briefly connect an additional pair of driving wheels. Naturally, such connections should be made automatically, without the participation of the driver. To implement such solutions, automotive designers began to use special multi-plate clutches, which, if necessary, connect the wheels of the rear axle in addition to the constantly rotating front wheels.

The all-wheel drive system implemented in this way is much simpler than classic off-road designs. There is no transfer case here, and only a pair of gears for power take-off and an output shaft are provided near the front differential.

Subsequently, the developers came up with the idea of using center differentials, equipped in addition to forced blocking also self-locking mechanisms. Using various solutions (viscous coupling or Torsen differential), the developers strove for a single common goal - partial blocking of the center differential in order to increase the controllability of the car - if any of the axles slipped, the triggered lock did not allow the differential to turn off the second pair of wheels and the torque from the engine continued act towards them. Cars with the presented all-wheel drive option are marked with the abbreviation AWD.

Differential Thorsen

However, the couplings also differ significantly from each other, regardless of the similarity of the principle of connecting the wheels of the second axle. One of the first couplings began to be used by Volkswagen engineers for their Golf hatchbacks. We are talking about the proprietary Syncro transmission, where the installed clutches were not compressed, but worked in a silicone fluid that thickens under increased load and is able to independently transmit rotation. The presented viscous coupling was uncontrollable and was not able to transfer all 100% of the moment to the rear axle. In addition, even with rather short slips, the silicone boiled, which led to overheating and subsequent combustion of the coupling.

Viscous coupling (viscous coupling)

More advanced design used on early models Ford Escape. Couplings have already been used here, compressing through the work of wedge-shaped slots and balls. These clutches, although they worked much more clearly, they could cause very sharp and sensitive shocks at the moment of rotation.

Haldex coupling

A kind of revolution among the couplings used in all-wheel drive systems is the appearance in the late 90s of the last century of the first generation of the Haldex coupling. In such a device, the disks were compressed using a hydraulic cylinder with a pump to generate oil pressure. The pump was mounted on one of the halves of the coupling, the drive to it came from the other half. Now, in the event of a difference in the speed of rotation of the wheels of the front and rear axles, the compression pressure increased, and the clutch was blocked. Compared to previously installed couplings, Haldex worked very smoothly and became a serious success.

It is worth bearing in mind that modern technology and the materials used have made it possible to manufacture a truly high-tech coupling that can be kept in a partially connected state without fear of overheating. Thus, the manufacturers managed to distribute the torque transmitted to the pairs of wheels in favor of the rear axle, providing the car with “classic” handling and all-wheel drive capabilities. Taking into account the flexibility of the algorithms used and the very deep degree of development of the design of the multi-plate clutches used, in the modern period of time this is the most demanded solution for organizing an all-wheel drive transmission, which is unlikely to be replaced by anything in the next few years.

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Almost every motorist has an idea of such advantages of all-wheel drive, compared with front- or rear wheel drive vehicles, How:

increased permeability;
improved dynamics, regardless of the condition of the coating - there is practically no wheel slip;
better handling, cornering stability, movement along optimal trajectories.

Cross-country ability is crucial for extreme off-road riders or drivers who have to wind up kilometers in Russian hinterland(where the condition of the roads can hardly be called satisfactory). The rest of the advantages of the scheme with all the drive wheels are relevant for literally every car. The idea was appreciated by manufacturers, today almost all leading companies offer all-wheel drive versions of not only SUVs and crossovers, but also passenger models, supercars and sports cars.

All-wheel drive options.

The term "all-wheel drive" covers many technical solutions that have their own characteristics. Experienced motorists and professionals distinguish several varieties of such systems:

pluggable - part-time;
permanent - full-time;
connected automatically (if necessary), in fact, automated part-time - Automatic 4WD, on-demand;
adaptive with electronic control torque distribution (or with other control principles) - often referred to as.

It is customary to refer to this group and hybrid models with their own electric motors installed on each wheel (axle). Despite the differences in technical implementation, the principle remains the same - the force generated by the power unit is distributed to all wheels.

Each of the schemes has inherent design features, advantages and disadvantages in certain operating conditions.

Part-time (connectable).

The simplest option in terms of technical implementation. When driving on paved roads, only one axle is driven. The connection of the second one is carried out by the driver independently (manually or by giving a command to electronic actuators).

There is no center differential (other devices with similar functions). The operation of a car with all-wheel drive constantly on is not recommended (in certain conditions it is simply dangerous) - on normal surfaces, intensive wear of tires and transmission units is observed, fuel consumption increases, maneuverability deteriorates and controllability is partially lost when cornering.

It is most comfortable to drive a car off-road, on city streets and highways, the second bridge MUST BE DISCONNECTED!

Full-time (permanent).

Assumes a constant transmission of torque to all wheels of the car. Structurally, such a distribution (not necessarily symmetrical 50/50, 40/60 options are more common, 30/70 is used, etc.) is provided by installing a center differential or controlled (forcibly or automatically) mechanically or electrically by clutch mechanisms.

The presence of this node eliminates the main drawback of all-wheel drive and provides comfort when driving on hard surfaces. To overcome off-road, the center differential is blocked; in the absence of this function, the off-road properties of the car are noticeably lost.

Full-time is great for operation in any conditions - in the city and on the highway, on wet and snowy surfaces, in mud and on real off-road. In the hands of an experienced driver, the car demonstrates maximum handling, dynamics and a high level of safety. The payoff for the benefits is a high price and increased operating costs due to increased fuel consumption.

Video No. 1 (which is better Full-time or Part-time, the main differences).

Adaptive.

The solution is positioned by manufacturers as an improved version of part-time. In most cases, a constant transmission of torque to all wheels is maintained, but, depending on the conditions, the distribution varies widely (up to 0/100, although 15/85 is more commonly used, to 85/15).

Theoretically, the drive retains all the advantages of a constant full, and due to the redistribution of forces, it adapts to the nature of the road surface, increasing comfort for the driver and reducing fuel consumption and other costs. In practice, the finite response speed of electronic control units (it is these devices that perceive sensor signals and control torque distribution) can lead to switching delays.

The disadvantage did not become an obstacle to the rapid development of technology; almost all well-known automakers offer their own variants of schemes. Adaptive drive today is more common than other varieties. It is considered the best solution for wet roads and snow-covered city streets, but not always adequate when driving off-road.

A good alternative is selective, using the same technology, but leaving the decision to the driver. Experienced motorists consider it the best possible, but it is not easy for beginners to master the complex controls and choose from a variety of options optimal.

On-demand (automatically connected).

The principle and technologies are used, almost similar to adaptive options. This allows manufacturers and retailers to present vehicles as having permanent all-wheel drive.

In fact, the machine in normal mode has one drive axle, and the second one is connected automatically only when certain situation(for example, when slipping the drive wheels). Actually, this approach is fraught with the main danger - the driver relies on all-wheel drive properties, while receiving such a car with a certain delay, determined by automation devices.

Among the advantages are excellent behavior on snow-covered roads, low cost and minimum operating costs. For off-road, the solution is practically unsuitable, therefore, machines designed for operation in appropriate conditions are not equipped with such systems. The combination of advantages gives car manufacturers reason to direct significant efforts and funds to improve technologies and designs and to expand the serial production of cars in this design.

Video No. 2 on the principle of operation of the On Demand system

Hybrid.

In fact, due to the presence of electric motors that directly transmit torque to the wheel or axle, it most closely matches the properties and characteristics of adaptive options. The difference lies only in the implementation of aggregate management.

The solution is not cheap and today it is used mainly on expensive cars premium segment and sports cars.

Four-wheel drive of popular car brands.

As all-wheel drive vehicles are increasingly in demand, the giants automotive industry pay maximum attention to the development and implementation of appropriate solutions. As a result, almost every brand has branded systems that, to one degree or another, satisfy the needs of motorists.

Audi.

The German manufacturer has been developing and using all-wheel drive technology for over 35 years, united by the common quattro brand. The systems are used not only on crossovers and SUVs, they are equipped with cars (as a rule, in top trim levels) and sports cars, supercars.

There are several options available:

quattro® based on a multi-plate clutch (wet, Haldex), mainly for vehicles with a transverse engine. Although the company talks about permanent PP, in fact it is an on-demand with a front drive axle and a connected rear axle.

Video #3.

quattro® with center differential (self-locking) Torsen or other types (e.g. with planetary gears) and electronically controlled torque distribution. It is installed, as a rule, on a car with a longitudinal engine. Sharing with sports differentials is possible.

Video No. 4 about the principle of operation of the Torsen differential.

quattro® ultra. In the scheme, the central differential is replaced by a Magna multi-plate clutch on the gearbox shaft, an additional cam clutch is used to disable the rear right axle shaft. As a result, the car receives a leading front axle and a plug-in rear axle (in fact on-demand) as in the younger series.

Video #5 (full quattro drive with ultra technology).

bmw.

Since 2003, all-wheel drive vehicles from Bavaria have been equipped with the fourth generation of xDrive systems.

The development of BMW is an adaptive scheme with a normal distribution of torque between the front and rear axles 40/60. Continuous stepless redistribution (up to 100% on one of the axles) is carried out by a multi-plate friction clutch. Management - electronic, the algorithm provides joint work with a dynamic stability control system.

Video #6 (full BMW drive xDrive).

Volkswagen.

Most of the manufacturer's all-wheel drive solutions are united by the 4Motion trademark. Since 2008, the scheme with the installation of an electronically controlled friction clutch Haldex. Thanks to this, cars get an on-demand drive with a permanently engaged front axle and a connected rear axle.

The 4xMotion system is also used, which is a quattro version with an electronic or manual Torsen differential lock (in normal mode- ratio 50/50 or 38/62).

Video No. 7 (the principle of operation of the 4Motion system).

Mercedes.

Most Mercedes all-wheel drive systems powered by passenger cars mobiles, crossovers and SUVs, received the common commercial name 4Matic, although they use different technical solutions:

The 4Matic Generation IV is an adaptive permanent drive with a lockable cylindrical center differential and electronically controlled torque distribution (normally 40/60, 45/55 or 50/50).

4Matic V generation (first serial application in 2013) uses a power take-off unit (PTU) built into the gearbox, and is used on cars with a front-wheel drive scheme. In normal mode, the maximum (up to 100%) is given to the front axle, and the rear axle is connected depending on the situation (On-demand option).

Video No. 8 (how the 4Matic system works).

Honda.

The abbreviation SH-AWD (from the English. Super Handling All-Wheel Drive), which literally means Super Controlled All-Wheel Drive System, fully reflects the features of the circuit developed by Honda.

In motion, the torque is distributed between the axles in the range from 30 to 70% of that given by the power unit, while it is possible to adjust the torque on each of the rear wheels up to 100% received by the axle. This unique solution maximizes the effectiveness of the adaptive sensor in all situations.

Also used:

VTM-4 - with a permanent connection of the front axle and transmission to the rear axle shafts through 2 multi-plate clutches;
several varieties of on-demand, united by the marketing name RealTime 4-wheel Drive .

Video #9 (SH-AWD drive).

Nissan.

The manufacturer installs several all-wheel drive systems:

ATC (Active Torque Control). It uses the connection of the rear axle with an electromechanical clutch at the signal of the ECU.

All-Mode 4×4-i — double clutch controls each of the rear axle shafts.

ATTESA E-TS - Similar to ATC, but used to connect the front wheels.

Mitsubishi Motors.

Some of the world's best all-wheel drive solutions include:

Multi select - the rear axle is connected through a multi-plate clutch, it is possible to turn off the all-wheel drive and lock (distribution 50/50).
Easy select - hard connection of the front half-axle;
Super Select - similar to the previous one, but with a center differential (lockable).
ACD-AYC - adaptive all-wheel drive with torque distribution between the wheels.

Everyone uses their own all-wheel drive schemes well-known manufacturers, many of them will repeat the solutions described above.

Lists of vehicles with various all-wheel drive options.

When choosing a car with "all leading" it is convenient to have at hand for each type of PP a list containing a list current models, indicating characteristic features aggregates.

Such lists, including release models after 2012, are presented below.

Full-time (permanent).

The solutions differ in the design of the transfer case and the method of locking the center differential (it is listed after the model name).

Bugatti Chiron, Veyron Grand Sport, the fastest production cars in the world use a mid-engine scheme with electronically locking front and rear differentials.
Chevrolet Niva, Lada Niva, Lada Urban - manual.
Daihatsu Be-Go, Daihatsu Terios - FullTime-H scheme from Toyota, manual.
Hummer H2, H3 with Borg-Warner transmission.
Jeep Grand Cherokee Limited and Overland (standard), Laredo (optional) with Quadra-Trac II 4x4, Grand Cherokee Limited and Overland with optional Quadra-Drive II 4x4 with electronic lock rear differential.
Land Rover Defender, Discovery, Discovery Sport, Range Rover, Range Rover Sport - with locking center and rear differentials and reduced range of gears
Mercedes-Benz G-Class.
Subaru Forester, XV, WRX, Tribeca - for cars with manual Symmetrical AWD with self-blocking viscous coupling (CDG)
Suzuki Vitara Grand Vitara- 43/57 manual, low gear.
Toyota 4Runner, FJ Cruiser, Harrier, Land Cruiser, Land Cruiser Prado, Sequoia, Tundra - Torsen, electronic, forced.
Toyota Highlander - free differential.
Tagaz C190.

Adaptive.

Acura CDX, MDX (in Techno and Advance SH-AWD trim levels), RDX Techno SH-AWD, TLX are equipped with Honda's SH-AWD.
Alfa Romeo Brera Q4 Torsen.
Alpina B3 Biturbo Allrad, B6, B7, D3, XD3 – xDrive from
Audi A4, A4 Allroad, A5, A6, A6 Allroad, A7, A8, Q5, Q7, R8, RS4, RS5, RS6, RS7, S4, S5, S6, S7, S8,SQ5,SQ7 - Torsen self-block, default (front/ rear axle) 40/60, in the process of redistribution from 70/30 to 15/85. For most, sports differentials are available, for some (A4 Allroad, A5 with manual transmission, RS5, RS6) - traction vector distribution.
Audi RS5 Coupe - crown gear differential.
Bentley Bentayga, Continental Flying Spur, Continental GT, Continental GT Speed, Continental GTC, Continental Supersports - self-block Torsen (40/60).
BMW X1, X3 - optional, X4, X5, X5M, X6, X6M - in the base configuration, models 1-, 3-, 4-, 5-, 6-,7 Series, 3 Series GT, 5 Series GT use an all-wheel drive scheme xD
Cadillac ATS.CT6, CTS, STS (30/70),
Genesis G80 - the distribution is normal 40/60.
Genesis G90 - HTRAC by Hyundai, electromechanical, from 10/90 all the way to 90/10.
Honda Legend, MDX - uses SH-AWD.
Honda Pilot, Ridgeline - VTM4 Schematic
Hyundai Genesis, Genesis G70, Kona proprietary HTRACi, with electromechanical clutch and distribution from 10/90 in normal mode up to 90/10 depending on conditions
Infiniti JX35, QX30, QX56, QX60, QX70, QX80 - Nissan Intelligent All Mode 4×4-I installed
Jaguar E-Pace, F-Pace, F-Type, XE, XF, XJ, X-Type - Intelligent Active DriveLine with Torque Vectoring (normal 30/70 to 50/50 or 0/100).
Jeep GrandCherokee (SRT8) fitted with a Quadra-Trac SRT 4 x4 electronically controlled single stage transfer case
Lamborghini Urus-Torsen.
Land Rover Range Rover Evoque, Range Rover Velar - Intelligent Driveline Dynamics with dynamic distribution from 90 to 10% in any direction.
Lexus GS300, GS350, GX460, GX470, IS250, IS350, LS460, LS600h, LS600Hl, LX450d, LX570 - DiffLock (Torsen) with 38/62 distribution.
Lexus RX300, RX330t - with normal distribution 50/50 with a free differential.
Lexus RX350 - 50/50 normal distribution with DiffLock.
Maserati Levante, samoblok, adjustable from 40/60 to 0/100.
Maibach 57, 62 - classic 4Matic IV.
Mercedes-Benz C-Class, CL-Class, CLS-Class, E-Class, GL-Class (distinguished by 50/50 distribution), GLA-Class, GLC-Class, GLE-Class, GLK-Class, GLS-Class, M-Class (50/50 split), R-Class, S-Class, V-Class, X-Class - branded 4Matic IV
Mitsubishi Eclipse, Eclipse Cross, Outlander - S-AYC.
Mitsubishi Lancer Evolution - ACD + AYC.
Nissan Juke, Murano, Pathfinder, Patrol, Teana, X-Trail – All Mode 4×4-I
Porsche 911 Carrera, Cayenne, Macan, Panamera - Porsche Traction Management (PTM) redistribution of power to honey 4 wheels
Renault Kadjar — All Mode 4×4-I by Nissan
Skoda Kodiaq, Octavia, Superb, Yeti - Haldex clutch is used, part of the power is always given to the rear axle (5-50%)
SsangYong Actyon, Actyon Sports, Chairman, Korando, Korando Sports, Tivoli - Active AWD with dynamic torque distribution to the rear axle.
Subaru Forester, Outback - proprietary Symmetrical AWD with torque distribution (ACT);
Subaru WRX STI with manual transmission - branded Symmetrical AWD with limited slip differential (DCCD)
Subaru Outback, Legacy - Proprietary Variable Distribution Symmetrical AWD (VTD).
Toyota RAV4 (III) - with power shift back.
Volkswagen Touareg - 4xMotion

on-demand.

The solutions differ in the bridge acting as a leader in the normal mode and in the design of the coupling (some features are in the comments to the names of the models in the lists).

Schemes with the connection of the rear axle.

Audi A3, A3 Sportback, Q3, RS Q3, RS3 (electro-hydraulic clutch), S3, TT. TT RS, TTS in quattro version.
Audi A4, A4 Allroad, A5, Q5, A6 (in perspective) in quattro ultra version.
Cadillac SRX, XTS - Clutch
Changan CS75 - option, up to 50% power, multi-disk.
Chery Tiggo, Tiggo 5 - optionally installed on the most expensive equipment.
Chevrolet Captiva, Traverse - automatic power distribution.
Chevrolet Tracker-Haldex.
Chrysler 200 - transmission to the second axle is possible up to 60% of the moment.
Citroen C4 Aircross, C-Crosser - with manual mode selection and automatic connection second axle in 4WDAuto mode, center differential lock in 4WD Lock mode.
Dodge Journey.
Ford EcoSport - automatic Dana clutch, with the ability to forced inclusion 4WD mode.
Ford Edge, Kuga, Taurus - with electric coupling connection.
Ford Escape, Maverick - with RBC electronic multi-plate clutch.
Ford Explorer - Terrain Management 4WD System, electromagnetic friction.
Geely Atlas (NL3) coupling connection
Haval H2, H6 clutch - electromagnetic multi-plate NexTrac from BorgWarner, adjustable from 90/10 to 50/50.
Honda CR-V, Crosstour, Fit, HR-V, Jazz, Odyssey–RealTime 4WD based on DPS (two pump layout)
Honda Grace, Vezel (hybrid) - RealTime 4WD with viscous coupling.
hyundai Creta, grand santa Fe, Santa Fe, ix25, ix35, ix55, Tucson - multi-disc, 4WD Auto and
Hyundai Terracan - branded ATT.
Jeep Cherokee (Sport, Longitude, Limited), Jeep Renegade - Jeep Active Drive 4x4 with traction control Select Terrain. The Cherokee Trailhawk comes standard with an upgraded Jeep Active Drive Lock 4 x 4 with a locking rear differential.
jeep compass, Jeep Liberty as standard they use Freedom Drive 4 x 4 with the connection of the back of the e / m clutch.
KIA Sorento, Sportage - electronically controlled Magna, with power redistribution in the range from 100/0 to 50/50.
Lamborghini Aventador LP 700-4, Centenario LP 770-4, Huracan LP 610-4 is an intelligent Haldex-based system developed in-house.
Lexus NX200, NX200t, RX200t - with distribution from 100/0 to 50/50.
Luxgen 7 SUV - with the possibility of forced manual activation.
Mazda 6.CX-5, CX-7, CX-9 - Active Torque Split AWD, electronic.
Mercedes-Benz A-Class, B-Class, CLA-Class - 4Matic V.
Mini Clubman, Countryman , Paceman - All4, similar Active Tourer from BMW, distributing t 100/0 to 50/50.
Mitsubishi ASX - Multi-Select 4WD.
Nissan Qashqai, Qashqai+2 - ATC.
Opel Antara, Insignia, Mokka - intelligent system, multi-disk.
Peugeot 4007, 4008 - there is a Lock mode that allows you to give 50-82% to the connected bridge.
Renault Duster, Kaptur, Koleos - with forced on and off functions.
Seat Altea - scheme based on Haldex
Skoda Kodiaq - uses Haldex 5 to implement
Suzuki Kizashi, Swift - up to 50% of the moment can be reloaded.
Toyota CH-R, RAV4 (IV), Matrix, Sienna, Venza - multi-disc, electronic control.
Volkswagen Amarok, Caddy, Golf, Passat, Phaeton, Sharan, Teramont, Tiguan - the classic 4Motion (some differences are only in the designs and generations of the clutches used).
Volvo S60.S80, S90, V40,V60, V90,XC40, XC60, XC70, XC90 is Haldex based electronic control solution.

Schemes with connecting the front axle.

Alfa Romeo Stelvio Quadrifoglio is a sports five-seat crossover with Q4 and Torque Vectoring system, electronic.
Cadillac Escalade Downshift
The Chevrolet Tahoe is practically the twin of the Cadillac Escalade.
Dodge Charger - uses clutches to connect.
Dodge Ram - 2 modes: hard connection and "on demand".
Ferrari FF - 4RM works only in Snow and Comfort modes, the rest of the time - rear-wheel drive
Ferrari GTC 4 Lusso - 4RM-S, differs from its predecessor in rear wheel thrusters
Foton Sauvana - BorgWarner Torque-on-Demand multi-plate clutch and transfer case.
Haval H7, H8, H9 - BorgWarner Torque-on-Demand transfer case.
Infiniti EX25, EX35, EX37, FX30d, FX35, FX37, FX45, FX50, QX50 - ATTESA E-TS from Nissan, hydromechanical.
Isuzu Bighorn - TOD ("Torque on Demand"), electronically controlled multi-disc.
GMC Yuckon on the GMT platform
KIA Mohave - electronic, with the ability to force 4WD and disable ESP.
KIA Stinger with electronic connection and traction control.
Lamborghini Gallardo, viscous coupling (Viscous Traction).
Land Rover Freelander - scheme with
Lexus NX300, NX300h, RX400, RX450 - E-Four intelligent system.
Maserati Ghibli and Quattroporte Q4 - multi-disk.
Mitsubishi L200, Pajero, Paiero Sport under the Super Select scheme.
Nissan GT-R-ATTESA-ETS
SsangYong Rexton - TOD 4WD.
Toyota FJ Cruiser -MultiMode (with several operating modes).

Hybrid.

Acura NSX is a sports coupe with a hybrid power plant. rear drive axle and electric motors on the front wheels.
The Acura RLX is a front-wheel drive hybrid sedan with individual rear-wheel electric motors.
Audi TT Offroad - driving front axle and electric motor in the rear.
Honda NSX is a hybrid with a rear axle and 2 electric motors in the front.
Lexus RX400h, RX450h - with electric motors on the rear axle
Tesla Model X, S - each axle is driven by its own electric motor.

Part-time.

Cadillac XT5.
Chevrolet Trailblazer.
DW Hower H3, H5
Fiat Fullback (Easy Select installed by Mitsubishi).
Ford F150, Ranger (with automatic torque distribution during operation).
Foton Tunland (series of low gears).
Great Wall Hover H3, H5, H6, M2, M4, Wingle.
Hyundai Terracan with
Isuzu D-MAX (downshift), MU-X.
JAC S1.
Jeep Wrangler (Rubicon, Sport, Sahara) and Wrangler Unlimited (Rubicon, Sport, Sahara) with Command-Trac 4×4 or Rock-Trac 4×4 (based on NV241).
Lincoln Navigator.
Mazda BT-50.
Mitsubishi L200, Pajero, Paiero Sport under the Easy Select scheme.
Nissan Armada, Navara, NP300, Terrano, Terrano Regulus, Xterra.
SsangYong Kyron Stavic.
Suzuki Jimny.
Suzuki SX4 - on-demand and lock modes are available.
Toyota Fortuner, Hilux Pick Up.
Tagaz Road Partner with reduction gear.
Tagaz Tager
UAZ 3151, UAZ Patriot, UAZ Patriot Pickup, UAZ Hunter.

Thus, in the world of PP there are several trends:

Expansion of application on passenger cars in order to ensure maneuverability and stability;
The emergence of numerous SUVs with similar passenger systems;
Shifting priorities even on SUVs towards an adaptive or automatically connected drive.

Each driver has a choice of which car model to prefer. Everyone wants to see in their garage a powerful and reliable SUV who would overcome any difficulties. Each car has a number of technical characteristics, and an important aspect when choosing an SUV or crossover is the availability of all-wheel drive or plug-in drive. Many will agree that full permanent drive is much more convenient and better.

In this article, we will try to understand all the positive and negative sides of full-time permanent drive in crossovers.

Connected or permanent?

Many will say that there is not much difference between plug-in and all-wheel drive, since this technology will work just as confidently in both situations. But experienced drivers surely know how the difference exists. It's all about fuel, because with the constant operation of all-wheel drive, fuel consumption increases markedly. Owners of older cars are probably aware of this. Even modern cross-country vehicles with a power distribution system still consume more fuel than SUVs with plug-in or just front-wheel drive.

Fuel consumption also depends on the driving style of the driver. If you drive the car slowly and evenly, then fuel consumption will not exceed the norm.

As practice shows, even passenger cars sometimes consume more fuel than large SUVs with full permanent drive. If you are a careful driver, then you can not be afraid of a huge expense, since most of the responsibility still lies on the shoulders of the car owner.

The increased consumption is due to the fact that the car drives along a curve or on heavy off-road. With such a ride, differentials are connected, which select extra power. And if the car moves on a flat and straight road, then the car consumes no more than the average. Nowadays, there are not many cross-country or off-road riders. Many drivers prefer driving in urban areas and rarely even go out of town, so they choose SUVs with all-wheel drive. And lovers steep slopes and quarries do not even think about what type of drive they should choose.

In winter, all-wheel drive still becomes the leader, since drivers do not always have time to connect all-wheel drive on an icy track, so accidents often happen. With a constant drive, the driver can feel confident even on the rink. But it is worth considering that such SUVs are much more expensive than cars with plug-in or only front-wheel drive.

Don't be tempted to buy cheap crossovers with the so-called all-wheel drive or plug-in all-wheel drive, since they still do not reach the level of reliable SUVs. This is because they are not equipped with a frame structure, underrun bars, and low gears. Without these features, no car can cope with heavy off-road.

On the one hand, permanent drive has a number of advantages, since the driver does not have to constantly connect all-wheel drive. On the roads with a reliable car, everyone will feel at their best, but at the same time, such cars cost a lot, plus everything, because big expense fuel pollutes the environment.

We should talk about representatives of cars with all-wheel drive. And the first on our list will be Acura MDX- a five-door SUV that can accommodate up to five people in the cabin. Manufacturers approached the technical equipment with responsibility, so the SUV has a short wheelbase, independent suspension, impressive ground clearance, as well as a six-cylinder three-liter engine with a power of about 290 horsepower and an automatic six-speed transmission. In just 7.5 seconds all-wheel drive SUV accelerates to 100 kilometers per hour.

Another version of the Acura MDX SUV is equipped with a six-cylinder engine with a volume of 3.7 liters. We can say that this car has the same qualities as the previous car of this model range. The maximum speed of the car reaches about 190 kilometers per hour.

Acura RDX

The next SUV is a representative of the same car company. The Acura RDX is a five-door car that seats up to five people. In length, the overall SUV reaches 4.6 meters, and the width of the car is 1.8 meters. If speak about technical equipment, it's pretty good. It should be noted six-cylinder engine with a capacity of 270 horsepower. With such a motor, the SUV accelerates to a hundred kilometers per hour in almost 8 seconds. Of course, it is not as fast as previous models.

Another representative of the automobile company Acura is all-wheel drive petrol SUV, whose name is Acura SLX. It also has permanent all-wheel drive and can accommodate up to five people. The main advantage of this SUV is a six-cylinder engine, the power of which is about 190 horsepower. Three-liter is able to disperse the car in 10 seconds to a hundred kilometers per hour. And the maximum speed that this model can reach is 166 kilometers per hour. Also worth noting is the five-speed manual transmission and reliable suspension. Acura car SLX.

The next SUV of the same lineup is equipped with a 3.5-liter engine. In all respects, this model is similar to the previous one, however, there are some discrepancies.

For example, power has increased. The engine currently has 215 horsepower, much more than previous model. And the automatic four-speed transmission is different from the Acura SLX 3.2 version. It is also worth noting that the Acura SLX 3.5 accelerates to 100 kilometers per hour in 9 seconds.

Acura ZDX is a four-door car with a 3.7-liter engine. The SUV can also accommodate up to 5 people in the cabin. The car has an impressive size. In length, it reaches almost five meters, and the width of the SUV is 1.9 meters. Acura ZDX is equipped with an impressive ground clearance, short wheelbase, six-cylinder engine 300 horsepower. This is so far the fastest SUV that we talked about on this moment. The all-wheel drive vehicle is equipped with an automatic transmission, independent front and rear suspension. It is worth noting that the car is capable of accelerating up to 205 kilometers per hour.

We've finished looking at Acura's SUVs and moved on to the Alpina XD 3 Biturbo, a six-seater SUV powered by a 350-horsepower six-cylinder, three-liter engine. It is worth noting the automatic transmission. Full permanent drive and independent front and rear suspension. Note that the Alpina XD 3 Biturbo SUV justifies the Biturbo prefix, as it can accelerate to 255 kilometers per hour.

ARO 10

ARO 10 - three-door compact crossover with all-wheel drive. The car has an impressive ground clearance, four-cylinder engine, the volume of which is 1.4, which is a rather modest result. And the power is not so stunning, since it is equal to 58 horsepower. It is worth noting a manual gearbox with all-wheel drive.

Absolutely the same data has ARO 10 with a motor, the volume of which is 1.4 liters. But still, this model is slightly more powerful than the previous one, the power of the SUV is 62 horsepower.

And the third representative of the ARO 10 lineup is an SUV with a 1.6-liter engine and its power is 72 horsepower. The car also accommodates up to five people, is equipped with a four-cylinder engine and mechanical box gears.