A traction Control System (TCS), also known as ASR or TRC, is a system that enables a car to achieve optimum traction under various driving conditions. The control device of the Traction Control System is a computer, which detects the speed of 4 wheels and steering wheel steering angle. When the car accelerates, if the speed difference between the driving wheels and non-driving wheels is detected to be too large, the computer immediately judges that the driving force is too large and sends out a command signal to reduce the engine oil supply to lower the driving force, thus reducing the slip rate of the driving wheels.
The computer grasps the driver’s steering intention through the steering wheel angle sensor and then uses the left and right wheel speed sensors to detect the difference between the left and right wheel speeds, thus judging whether the car steers to the same extent as the driver’s steering intention. Suppose understeer (or oversteer) is detected. In that case, the computer immediately determines that the driving force of the drive wheels is too high and issues a command to reduce the driving force in order to achieve the driver’s steering intention.
ASR, whose full name is Acceleration Slip Regulation, is a traction control system or drive anti-skid system whose purpose is to prevent vehicles, especially high horsepower cars, from slipping on the drive wheels when starting and accelerating in order to maintain the stability of the vehicle’s driving direction.
ASR can reduce engine power by reducing the throttle opening or control wheel slip by the brakes to achieve control of the car’s traction. In a car equipped with ASR, the mechanical connection from the accelerator pedal to the gasoline engine throttle (diesel engine injection pump lever) is replaced by an electronically controlled throttle device.
When the sensor transmits the position of the accelerator pedal and the wheel speed signal to the control unit, the control unit generates a control voltage signal, and the servo motor readjusts the position of the throttle (or the position of the diesel engine lever) according to this signal, and then sends the position The signal is then fed back to the control unit so that the brake can be adjusted in time.
When the car is driving on a slippery road, the drive wheels tend to slip when the car accelerates without ASR, and if the rear-drive wheels slip, the vehicle tends to drift, and if the front-drive slips, the vehicle tends to lose direction. With ASR, the car will not have or can mitigate this phenomenon when accelerating. When turning, if a drive wheel slip occurs, it will cause the whole vehicle to drift to one side. When there is ASR, it will make the vehicle steer along the correct course.
In short, ASR maximizes the use of the engine’s driving torque to ensure stability during starting, acceleration and steering of the vehicle.
The difference between ASR and ABS is that ABS prevents the wheels from skidding due to being held during braking, while ASR prevents the car from skidding due to the drive wheels slipping during acceleration. ASR is an expansion on ABS, and the two complement each other.
ASR is only installed on some high-grade cars, but it is expected to become as popular as ABS in recent years because of the performance and technical integration between ASR and ABS.
When a car is braked on a smooth road, the wheels can slip and even lose direction. Likewise, when a car starts or accelerates rapidly, the drive wheels may slip, and on smooth roads such as snow and ice, it can cause loss of direction and become dangerous. The traction control system is designed for this problem.
The traction control system relies on electronic sensors to detect when the driven wheel speed is lower than the driving wheel (which is the characteristic of slipping), it will send a signal to adjust the ignition time, reduce the valve opening, reduce the throttle, downshift or brake the wheels, so that the wheels no longer slip.
Traction control system can improve the car driving stability and improve acceleration and improve the climbing ability. The traction control system is only installed on luxury cars but is also available on many ordinary cars from 2008 to 2013.
When used in conjunction with ABS, Traction control systems will further enhance the safety performance of the car. The traction control system and ABS can share wheel speed sensors on the axle and are connected to the trip computer to constantly monitor wheel speed. When slip is detected at low speeds, the traction control system will immediately notify the ABS to reduce the wheel slip. If slippage is detected at high speed, the traction control system immediately sends a command to the trip computer to command the engine to slow down or the transmission to downshift so that the slipping wheels no longer slip and prevent the vehicle from drifting out of control.
Traction control system uses a computer to detect the speed of 4 wheels and the steering wheel steering angle. When the car accelerates, if it detects that the speed difference between driving wheels and non-driving wheels is too large, the computer immediately judges that the driving force is too large and sends a command signal to reduce the engine oil supply, lower the driving force, thus reducing the slip rate of the driving wheel tires.
The computer grasps the driver’s steering intention through the steering wheel angle sensor and then uses the left and right wheel speed sensors to detect the speed difference between the left and right wheels, thus judging whether the car steers to the same extent as the driver’s steering intention. If understeering (or oversteering) of the car is detected, the computer immediately judges that the driving force of the driving wheels is too large and issues a command to reduce the driving force to realize the driver’s steering intention.
The traction control system of each manufacturer has the same function, but it is just called different. So, for example, Mercedes-Benz is called ASR, Toyota is called TRC, BMW is called DTC, Cadillac is called TCS, etc.
At present, the traction control system mainly consists of two control methods: brake torque control and engine torque control.
Braking torque control method
Braking torque is applied to the drive wheels that will be idling, and the excess torque output from the engine is consumed in the brakes to control the wheel slip rate within the desired range, similar to ABS.
The brake control method is faster than the engine control method and is more effective in preventing wheel spin when the car starts or when there is a sudden leap from a high to a low adhesion surface. The brake control method can also control each drive wheel independently, and the differential locking device has the same function.
However, this control method consumes the extra power output of the engine in the form of heat in the brake. Thus the brake heats up severely and affects its service life, which is not conducive to improving the economy of the car.
Engine Torque Control Method
The engine torque control method controls the engine torque input to the drive wheels to control the wheel slip rate within a suitable range.
The engine control method inputs the optimum driving torque to the drive wheels based on road conditions by varying the amount of fuel injection, ignition timing and throttle opening. Both of these methods can be used individually or in combination.
The use of engine torque control, in addition to slower response than the braking method, another essential problem is that in the asymmetric adhesion coefficient of the road can not achieve the best drive control, its effectiveness and ABS control system is similar to the case of low selection, in order to achieve the best control of the drive, that is, to maximize the economy, power, directional stability and maneuverability of the car, is now moving toward the engine torque, wheel braking, the direction of the best drive control. The direction of integrated control of both wheel brakes.