TRC (TRaction Control) is one of the names of the traction control system. It so happened that different car manufacturers call it differently, in the descriptions of car models you can find the abbreviations ETS, ASC, ASR, STC and many others. But regardless of the name, the task of this system comes down to preventing slipping of the front wheelset of your car.
Slipping, as a rule, appears when starting or trying to accelerate sharply on a slippery or viscous surface: on an icy road, in sand or mud: the engine roars, the wheels spin while idling, and the car does not move or moves at the same speed.
The structure and principle of operation of the TRC (TRaction Control) system
TRC (TRaction Control) is a system that simultaneously controls both the braking processes and the amplification of engine thrust. This system not only eliminates the slipping of the leading wheelset, but also regulates the tractive force of the engine - to values that are optimal for the particular road surface on which the car is moving.
Thanks to TRC, the driver is relieved of complex manipulations with the accelerator pedal when slipping, and the car itself acquires exceptional stability during a sharp start from a standstill or fast acceleration on slippery roads.
However, all automakers supplying their offspring with traction control systems, including Toyota, which installs the TRC system on cars (for Toyota C-class it is optional, and for all classes above it is included in basic configuration auto), emphasize that traction control is not an alternative to sensible and safe driving.
In addition, manufacturers remind how effective will be traction control, including TRC, depends on the condition of the road and the degree of tire wear.
Most traction control systems these days are electro-hydraulic. Of course, different manufacturers have their own know-how and traction control systems may differ slightly in design from each other. But still, in general, their principle of operation can be considered on the example of TRC.
TRC in the car controls the engine thrust due to the ability to control the air damper, ignition delay in the cylinders (in one of them or in several at the same time). Also TRC (TRaction Control) can increase or decrease the fuel supply to the engine and control the brake actuator.
At its core, TRC is a necessary component of a car's safety system, especially important for cars with a powerful engine, the slightest excess of traction of which leads to slipping of the driving wheels.
Without an adequately working TRC, a modern SUV is unthinkable, which a priori is obliged to overcome with honor that slippery and wet roads that their complete absence. TRC and racing models are indispensable, as the traction control system allows them to exit the corner with acceleration without wheel spin.
Sometimes you can hear the opinion that TRC deprives an experienced driver of the control he needs over the car. Moreover, this system is not just unpopular among motorsport fans - TRC regularly tries to outlaw in some of its forms, right up to Formula 1, where, due to controversy around the TRC, the rules even had to be adjusted several years ago.
However, for most car enthusiasts, TRC is a reliable assistant. This system not only allows you to get under way or accelerate without skidding on wet or icy roads, it also makes it much easier for a front-wheel drive car to pass bends.
It is known that on difficult turns in some cases there comes a moment when the front wheels are unable to pull the car and at the same time turn without skidding. TRC (TRaction Control), on the other hand, allows you to return control to the car.
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" movement makes the motorcycle jump, roll over and throw the pilot out of the saddle (highside). So, modern traction control systems are fighting to keep rear wheel on the verge of adhesion of rubber to the road surface and come into operation mainly just in the corners, when the risk of skidding the rear wheel 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 “ younger brothers "- got 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 Portimao, many noticed that when exiting a high-speed right turn with an ascent to the finish line, the motorcycle confidently lifted 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 operating experience of the editorial sporty BMW we can say that the Bavarian version of the "antibuks" still works roughly, leading to bullies 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 traction control carries both the charms of a BMW DTC and some templates similar to those used on the previous "ninja" (in fact, like Suzuki), which allows it to work not only in "combat", but and in a preventive mode, preventing attempts to break the wheel into 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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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: traction control TRC (Toyota), traction control ASR (Audi, Mercedes, Volkswagen), ETC system (Range Rover) and others.
Activated TCS prevents the driving wheels of the car from slipping when starting to move, sharp acceleration, cornering, bad road conditions and fast lane changes. Consider the principle of operation of TCS, its components and general arrangement, as well as the pros and cons of its operation.
How TCS works
The principle of operation of the traction control systemGeneral principle The 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:
- Feed pump brake fluid... This component creates pressure in brake system car.
- 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. Usually on dashboard there is a "TCS" button 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 TCS is installed on vehicles 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.
Consider different ways traction control implementations used by leading motorcycle manufacturers.
Deck of cards, palm, smartphone. This is the size of the spot on the rear tire of your liter sport bike. All of these are in one size, which is approximately 64 sq. cm. All this rubber-based area should transmit more than 160 hp. and more than 80 Newton meters of torque to the asphalt surface.
If you open the throttle too sharply, the ability to transmit all the power of the contact patch will not be able to, and the tire will begin to slip. It's not over yet and the bike will start to slide, but if you get greedy and don't leave out the grip coefficient, the bike will lose grip. It should be noted that the ideal rear tire slip is 15% faster than the front wheel rpm. In other words, if you are driving at a speed of 100 km / h in a corner, then the rear wheel can rotate 115 km / h without any problems. Naturally, if you have the skills to do this.
Since the tire with strong slippage cannot keep the motorcycle tilted, the bike begins to rotate around the vertical axis, straying from the intended trajectory. You have three options here. You can keep increasing the power to the tire and it ends up lowside. You can abruptly close the throttle, thereby stopping the power supply, the spot of contact will regain its grip with the surface, and the motorcycle will immediately launch you like a catapult - the highsad is more painful. Or, you can fine-tune the power and torque delivery to the rear wheel, keeping the spin speed under control, and thus keep the bike in a controlled skid.
Now it is time to ask myself: do I have the skills that can keep the bike sliding, and even at the peak of power and torque values? My name is Nikki Hayden, Kenny Roberts, Freddie Spencer? Of course not. As a result, at least six motorcycle manufacturers (Kawasaki, Yamaha, Ducati, Aprilia, BMW and MV Agusta) now produce superbikes with Traction Control (TC) that will tame the power of your motorcycle when needed. which he is able to transfer to the rear wheel, which means that severe consequences can be avoided.
Although the principle of traction control is very similar from different manufacturers, traction control is implemented in different ways: different algorithms, different sensors. We tried to understand these differences and explain how different factories implement traction control on their bikes. In part, all the details of the traction control management system are patented by the manufacturer and kept secret. Therefore, it is very difficult to gain access to the results of the work of engineers.
Yamaha offers six steps of traction control
All five motorcycle manufacturers who equip their bikes with TC systems (Aprilia, BMW, Ducati, Kawasaki, Yamaha) use high speed sensors on the wheels. These sensors were originally intended for use in ABS systems, where they have to read about 50 pulses per wheel revolution. Basically, braking control and traction control are identical math problems. In both cases, wheel slip or blocking results in a difference in wheel speed. Riders tend to view acceleration and deceleration as two completely different processes, but Newton and his Laws are not so picky. The change in speed is the change in speed. The underspeed detection sensor can easily handle the overspeed detection task.
The dark horse in this group is the MV Agusta and its F4 model. Unlike the others mentioned above who use wheel sensors to detect wheel slip, the Agusta monitors the engine speed instead. A sharp jump in engine speed, exceeding the permissible limit, is dictated by the specified ECU algorithms (Electronic Control Unit), and is considered as rear wheel slip. In general terms, this is similar to those traction control systems that are installed as tuning.
It would seem easy to make a traction control system that only works on data collected from wheel sensors. The wheel began to rotate faster - the ECU enters the work. This traction control system will even work in most cases. But modern liter sportbikes are more powerful than ever, and opening the throttle handle by 100%, in 1st gear, will send the user to a highside. To avoid this, you need to know the throttle position, as well as the engine speed and the selected gear. Fortunately, all of these bikes are fuel-injected and the numbers are known.
Ducati: If you're brave, you can turn off the traction control completely.
If not, use smooth adjustment
interference of electronics in rear wheel slip
You can stop there if you stick to a minimal approach. There is data about front and rear wheel speed, torque value and throttle position. Kawasaki and Yamaha are of this opinion and have not added additional traction control sensors to their bikes.
Ducati engineers went a little further than the two Japanese manufacturers. They added one accelerometer to measure the motorcycle's longitudinal acceleration. Ducati does not use information about the used gear ratio in transmission, tire radius, etc. Engineers have walked around this entire chain and uses an accelerometer to measure longitudinal acceleration.
BMW and Aprilia go a little further than Ducati, and their traction control systems include acceleration sensors (longitudinal and lateral acceleration) and two gyroscopes. It is not yet clear how the data collected from the lateral acceleration and yaw sensors are used.
Ultimately, sensors alone are not enough for a traction control system. The traction control system must reduce slip to a safe level, do it quickly, and do it in a controlled manner. The computer reduces the slip of the driven wheel by limiting the motor torque. There are three mechanisms to do this: disabling the cylinder, changing the ignition timing, or closing the throttle. Each of these methods has its own advantages and disadvantages.
1. Shutdown of the cylinder. This is achieved by skipping fuel injection on the intake stroke, or by applying a spark (but this will result in unburned fuel in the exhaust gases, which will increase harmful emissions). Cylinder shutdown has an immediate engine response (requires less than 180 degrees of revolution crankshaft 4-cylinder motor), wide range (the torque value can be changed from 0 to 100%), but the changes will be rough, the change will be 25%.
2. Reducing the ignition timing. Has an immediate response as well as subtle intervention. But the power can only be controlled within about 20% without causing misfires.
3. Close the throttle valve (if throttle valves are servo-driven and controlled by wires (Ride by Wire). There is a wide range of powers (from 0 to 100% torque drop), but as a rule, this method has a slow response.
| Manufacturer | Sensors | Traction control mechanism |
| Kawasaki | Disconnecting cylinders | |
| Yamaha | Front and rear wheel gauge | Shutdown of cylinders, |
| Ducati | Front and rear wheel sensor, longitudinal acceleration accelerator | Disabling cylinders, reducing the ignition timing |
| Aprilia | Decreasing the ignition timing, closing the throttle | |
| Bmw | Front and rear wheel sensor, longitudinal accelerator, lateral accelerator, roll angle, yaw | Decreasing the ignition timing, closing the throttle |
All manufacturers include an anti-bilge option in their traction control systems. Antivilly is the prevention of angular movement of the motorcycle around the main (horizontal) transverse axis(pitch). It would be logical to assume that this is achieved based on information supplied by the gyroscope. But surprisingly, none of the manufacturers take advantage of this. Instead, the bike's wheel speeds are compared. If the front wheel slows down while the rear wheel continues to accelerate, the computer infers that the front wheel has lost contact with the ground and instructs it to reduce torque. Interference with the bike's wheelie performance depends on the vehicle settings or, in the case of Aprilia, the anti-wheelie control setting.
The five systems discussed here were only rated based on the number of sensors and actuators. Kawasaki traction control is the simplest of all systems. The Yamaha is slightly more complex than the Greens, with a similar set of sensors, but with the addition of electronic controls. throttle... Ducati's sensor unit includes one inertial sensor, but no electronic throttle. Aprilia and BMW supplied the most sophisticated systems, each with electronic control chokes and four inertial sensors. We must point out that complexity can be justified in any system if the development costs are offset by the increased capabilities of the traction control system.
Remember that traction control (traction control) will not save you 100% from situations that may arise when driving a liter sports bike without certain skills.
