Find out how a car's traction control system works and what types exist. Diagrams and videos about the principle of the system.
The content of the article:
For about 20 years now, various security systems have been installed on cars, they monitor the safety of braking and accelerating cars. Today, any modern car has such technologies.
Having passed a long period of time, and a difficult path, from simple systems, up to whole complex systems that are combined into several traction control systems.
What is traction control
Traction control system, or abbreviated APS is still called "traction control (PBS)", in English you can also see two names of this technology - Dynamic Traction Control (DTC) and Traction control system (TCS), in German it is referred to as Antriebsschlupfregelung (ASR) ...
Traction control is a secondary safety feature that works with the ABS anti-lock braking system in cars, trucks and SUVs. This electro-hydraulic system of the car makes it easier to drive a car on a wet road (it prevents the loss of grip of the wheels with the road due to constant monitoring of the slipping of the driving wheels of the car). Depending on the car manufacturer's firm, the traction control technology has the following names (types):
- ASR - installed on cars of such companies as Mercedes (as well as ETS), Volkswagen, Audi.
- ASC - installed on BMW vehicles.
- A-TRAC and TRC - on Toyota vehicles.
- DSA - available on Opel vehicles.
- DTC - mounted on BMW vehicles.
- ETC - Found on Range Rover vehicles.
- STC - on Volvo cars.
- TCS - installed on Honda vehicles.
ASR system and the nuances of its work
ASR helps prevent loss of traction at the wheels of the vehicle by using an electro-hydraulic system that controls the engine and brakes in adverse road conditions or if the driver uses excessive acceleration and the wheels begin to slip on the asphalt. ASR helps the driver avoid mistakes in adverse road conditions and helps the driver maintain control of the vehicle.
Professional drivers complain that ASR APS affects vehicle performance, but this standard equipment in high performance vehicles helps beginners and drivers who often overestimate their ability to control the vehicle in adverse weather conditions and regains driver control in unforeseen circumstances.
ASR technology has been in most cars and motorcycles since about 1992. It dates back to the early 1930s, when Porsche developed a limited slip differential that allows one wheel to spin slightly faster than the other to improve traction. The ASR system is closely related to ABS. From the first users of ASR, which was already complemented by the ABS system, there was BMW in 1979.
How the ASR system works
The main functions and purposes of PBS
The ASR system is based on the ABS anti-lock braking system. The functions implemented in the ASR are differential locks and torque control.
How the traction control system works and its nuances
The engine control unit monitors the rotation of the wheels and after turning on the ignition, the vehicle begins to move. Computer monitors compare the acceleration and speed of driving wheels to non-power wheels. The computer activates ASR when the wheel rotation exceeds the slip threshold. The ASR system activates the brake valve differential to control the brake cylinder and the engine torque is applied to the braked wheel. Traction control technology moves from differential brake control to motor control to reduce engine power. In some systems, ASR delays ignition or reduces fuel supply to specific cylinders to reduce power at speeds above 80 km / h. On the dashboard, you can see the warning lamp flashes when the system is triggered. Also, this technology can be disabled.
Description of other vehicle traction control systems
The TRC system is a traction control system developed by Toyota and is used on Toyota and Lexus cars. It is considered the most modern and efficient traction control system today.
The principle of operation of TRC is the same as for ASR, but all vehicle safety technologies are connected to work.
How the TRC Traction Control System Works
Advantages of the vehicle traction control system
The advantages of this technology include the following characteristics:
- Reducing the chances of damaging tires.
- Increased engine resources.
- Cornering safety on wet roads.
- Traffic safety on the winter road.
- Safe and comfortable start of driving on wet, winter and other roads with poor grip.
- Allows you to save fuel.
- Good handling and predictability on the road, which helps to feel comfortable on the track.
Traction control is a collection of mechanisms and electronic components of a car that are designed to prevent slipping of the driving wheels. TCS (Traction Control System) is the trade name for the traction control system that is installed on Honda vehicles. Similar systems are installed on cars of other brands, but they have different trade names: TRC traction control (Toyota), ASR traction control (Audi, Mercedes, Volkswagen), ETC system (Range Rover) and others.
Activated TCS prevents the vehicle's drive wheels from slipping when starting, accelerating, cornering, poor road conditions and fast lane changes. Let's consider the principle of operation of the TCS, its components and general structure, as well as the pros and cons of its operation.
How TCS works
The principle of operation of the traction control systemThe general principle of operation of the Traction Control System is quite simple: sensors included in the system register the position of the wheels, their angular speed and the degree of slippage. As soon as one of the wheels starts to slip, TCS instantly corrects the loss of traction.
The traction control system deals with slippage in the following ways:
- Braking of skidding wheels. The braking system is activated at a low speed - up to 80 km / h.
- Reducing the torque of the car engine. Above 80 km / h, the engine management system is activated, which changes the amount of torque.
- Combining the first two methods.
Note that Traction Control System is installed on vehicles with (ABS - Antilock Brake System). Both systems use the readings of the same sensors in their work, both systems pursue the goal of providing the wheels with maximum grip on the ground. The main difference is that ABS limits wheel braking, while TCS, on the contrary, slows down a rapidly rotating wheel.
Device and main components
ABS + TCS system diagram Traction Control System is based on anti-lock braking system elements. The anti-slip system uses as well as the engine torque control system. The main components required to implement the TCS traction control functions are:
- Brake fluid pump. This component creates pressure in the vehicle's braking system.
- Changeover solenoid valve and high pressure solenoid valve. Each drive wheel is equipped with such valves. These components control braking within a predetermined loop. Both valves are part of the ABS hydraulic unit.
- ABS / TCS control unit. Manages the traction control system using the built-in software.
- The engine control unit. Interacts with the ABS / TCS control unit. The traction control system connects it to work if the speed of the car is more than 80 km / h. The engine management system receives data from sensors and sends control signals to the actuators.
- Wheel speed sensors. Each wheel of the machine is equipped with this sensor. The sensors register the rotational speed, and then transmit signals to the ABS / TCS control unit.
TCS on / off button Note that the driver can disable the traction control. There is usually a TCS button on the dashboard that enables / disables the system. Deactivation of TCS is accompanied by the illumination of the indicator "TCS Off" on the instrument panel. If there is no such button, then the traction control system can be disabled by pulling out the corresponding fuse. However, this is not recommended.
Advantages and disadvantages
The main advantages of Traction Control System:
- confident start of the car from a place on any road surface;
- vehicle stability when cornering;
- traffic safety in various weather conditions (ice, wet canvas, snow);
- decline.
Note that in some driving modes, the traction control system reduces engine performance, and also does not allow full control of the vehicle's behavior on the road.
Application
Traction control system TCS is installed on cars of the Japanese brand "Honda". Similar systems are installed on the cars of other automakers, and the difference in trade names is explained by the fact that each carmaker, independently of the others, developed an anti-slip system for its own needs.
The widespread use of this system has made it possible to significantly increase the level of vehicle safety while driving due to continuous control of grip with the road surface and improved handling when accelerating.
The grip of the tires with the road surface - in everyday life "derzhak" - is worth its weight in gold. Needless to say, the manufacturers of technology go out of their way, coming up with all the new "cartoons" in order to use it most effectively. And if ABS became the "first sign", then the modern trend is traction control, in fact, ABS is the opposite.
"Derzhak" is not endless
Before getting into the electronic jungle of modern motorcycles, let's remember what we are fighting for. The "grip" is the maximum force applied to the wheel, at which it still holds on to the asphalt, does not slip. Moreover, it is important to understand that, roughly speaking, the tire does not care which side the force is applied from, the main thing is its maximum value. In reality, forces of different nature act on the tire. Both longitudinal actions (during acceleration or deceleration) and transverse (in a turn) try to shift it from the trajectory. In this case, the vector sum of forces (or superposition) is still the main one. If, for example, we want to maximize the grip of the tires on the asphalt to counter centrifugal force, we will have to abandon the braking or acceleration on the arc. Or vice versa, you can only brake with maximum efficiency on a straight line, any turn will require its share of grip in the contact patch. But for a long time, tests have shown that the maximum "grip" on dry asphalt is achieved with a slight slip, practically on the verge of transition from rolling friction to sliding friction. It is this moment that the creators of anti-lock braking systems are trying to use for the benefit of the pilot, while simultaneously protecting them from skid, that is, sliding friction. When braking, the ABS systems allow the wheel to skid for a few moments and immediately - the electronics monitors the wheels to stop very quickly - they again allow the rubber to restore grip on the asphalt. Why not make the effect work for the benefit of overclocking? This is exactly what the Honda engineer thought when he developed the ABS + TCS system for the ST1100 Pan European, released in 1992. As soon as the difference in angular speeds of rotation of the wheels (and it was measured those two decades ago through ABS sensors) exceeded a certain value, the "brain" of engine control took the ignition to "late hours" (the motor was carbureted, and there was no way to influence the composition of the mixture), and the engine thrust dropped sharply.
It is easy to assume that the difference in angular speeds of rotation of the wheels decreased, and as soon as it reached a reasonable - in the opinion of the "brains" - the limit, the motor returned to normal mode. But that system saved the motorcycle from active slipping when accelerating in a straight line, not saving it from lowsides when carelessly handling the throttle in turns. Indeed, it is much easier to break the wheel into slipping while leaning, due to the fact that part of the "grip", as we remember, is spent on counteracting the centrifugal force. If the sum of the forces that fall on the contact patch of the tire with the road exceeds the friction force, the wheel will break into a skid, and the rear of the motorcycle will wobble outward, putting the bike sideways to the trajectory of the turn. Further, there are three possible scenarios for the development of the situation. The first, the best: the pilot did not get scared and did not close the throttle in a panic, but threw off the throttle quickly but smoothly - and the motorcycle stabilized. The second, "continued": the pilot continued to open the throttle, and in a moment the motorcycle "lay down" (lowside). Third, "brutal": if the pilot turned off the throttle too late or too abruptly, the rubber instantly regains reliable grip, but the kinetic energy of the "wobbling" motion makes the motorcycle jump, roll over and throw the pilot out of the saddle (highside). So, modern traction control systems are fighting to keep the rear wheel on the verge of rubber adhesion to the road surface and come into operation mainly in corners, when the risk of letting the rear wheel slip is much higher than average.
How do they do it?
Let's notice right away: there is no similarity between motorcycle and automobile traction control systems. In a world of four wheels, traction control systems not only play with engine thrust but also brake individual wheels. We have only one drive wheel and the engine thrust correction is exclusively downward. Motorcycle antibuks have now become such a fashionable trend that almost all motorcycle manufacturers are actively introducing such devices, but we will list the most prominent representatives of this new breed of electronic "mulek". The first systems of this century, designed to make the reaction to gas smoother and thereby combat the rear wheel drift on "civilian" vehicles, began to be used on the 2007 liter "gizer". There were no wheel speed sensors (the speedometer does not count), no gyroscopes, but there was a second row of throttle valves driven by a stepper motor, controlled by "brains". According to indirect parameters (motorcycle speed, selected gear, throttle position), the load on the engine was estimated, and based on these parameters, the controller of the ignition and injection systems, depending on the selected control program (and there were three of them in total), limited the traction, or rather, the speed set engine speed under one load or another.
The liter was followed by the "younger brothers" - they acquired multi-mode "brains", which are even on the current "600". The "stabilizer" on the MV Agusta F4 works according to the same principle. Yes, it works, but it’s too inaccurate. Not being able to track the road situation by direct parameters (angle of inclination of the motorcycle, rotation speed of both wheels), this way to protect the rear wheel from drift can only be called conditional. The next was the BMW concern in 2006 with a completely "civilian" R1200R. Here, the wheel speeds were monitored through the ABS sensors, and, as in the ancient "Pan-Europe", when slipping, the ignition became later, and the mixture was poorer, and the BMW ASC (Automatic Stability Control) system works much smoother and more agile. A little later, Ducati became a fighter for justice, introducing the DTC (Ducati Traction Control) system on the 1098R in 2008. Of course, it had little in common with a similar "pribluda" used in the WSBK, but nevertheless there were already speed sensors on both wheels (the signal was given by the brake disc mounting bolts), and traction correction (through changing the ignition timing and the amount of fuel supplied ) was made on the basis of "live" indicators obtained in real time, although also according to a template written in the memory of the control system (like in Suzuki and MV Agusta). The fundamental difference is that slippage was monitored here not only through a sudden increase in the crankshaft speed, but also through the speed of rotation of both wheels. The difference between "civil" traction and racing is that on serial sports bikes, unlike racing ones, there are no suspension position sensors, and in races, few people are interested in saving gasoline, and when slipping on racing Ducatis, the ignition was "chopped off". However, if this method is applied on a serial car with a standard exhaust, then after a couple of such anti-axle actuations, the catalyst will hang on the wire from the lambda probe, so the fuel is also “chopped off”, sacrificing a small loss of traction caused by the “drying” of the intake channels. The degree of "interference" of electronics in the nature of the motor is divided into eight steps, plus the system can be turned off altogether. However, on the new Multistrada, the wheel speed is no longer read by the bolts, but from the ABS sensors - this is much more accurate, because if you read the speed by the bolts, then you get 6-8 pulses per wheel revolution (that is, 60 and 45 degrees between pulses), and if through the "comb" of the induction sensor ABS, then you can get up to forty pulses per revolution. But returning to the chronology of events, let's be honest, the BMW ASC system did not go further than the boxer naked R1200R, because in 2009 DTC (Dynamic Traction Control) appeared on the sensational S1000RR sport bike - a nightmare for Japanese manufacturers. It can rightfully bear the title of a masterpiece of engineering, because it contains not only these same ABS sensors, but also a gyroscope that monitors the roll and trim of the car. It is precisely thanks to the gyroscope on the S1000RR that it is impossible to "overgrow" (of course, if the DTC system is not disabled at all), as well as to track the situation in the corner as accurately as possible (after all, if the antibuks is reinsured and starts working ahead of time, then less thrust will be realized, which will lead to an unnecessary loss of speed ).
For example, in the Slick mode, the engine thrust is cut by electronic chokes and injectors, it is worth the stern drift, but only when the motorcycle rolls more than 23 degrees, which implies adequately careful handling of the gas. But even during the journalistic test in Portimão, many noticed that when exiting a high-speed right turn with an ascent to the finish line, the motorcycle confidently lifted the front wheel into the air, despite the anti-virus program. BMW-shny electronics engineers limited themselves to vague explanations about the combination of factors (tilt-lift-acceleration), which confused the electronic "brain". In addition, from the experience of operating an editorial sports BMW, we can say that the Bavarian version of the antibuks still works roughly, leading to bad marks on the tires after several track sessions. Kawasaki engineers did the same on the ZX-10R Ninja, which debuted this winter. ("Moto" # 02–2011) - there the traction control carries both the delights of a BMW-shnoy DTC and some templates similar to those used on the previous "ninja" (in fact, like that of Suzuki), which allows it to work not only in "combat", but also in a preventive mode, preventing attempts to break the wheel in a skid at the root. Yamaha, on the other hand, decided that Super Tén? R? no gyroscope is needed, and was limited to the usual (by today's standards) antibuks, using only the readings of the ABS sensors. The result is as many complaints as enthusiasm.
Look into tomorrow.
In view of the increasing "electronicization" of modern motorcycles, switching to electronic throttle control, as well as the development of ABS systems, I think that in a dozen years, traction control will appear even on scooters. And perhaps not with induction sensors, which, as you know, start working only when a certain speed is reached (usually 15-20 km / h), but with Hall sensors, which do not care about speed (now on most cars, wheel speed sensors - "halls").
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