Chassis and body control system
- ABC body control system
The suspension shock absorber in the ABC body control system is installed between the wheel and the body. A coil spring and a hydraulic cylinder are installed at the position of the air bellows. The coil spring is supported in the direction of the wheel by an elastic disk connected to the shock absorber, and in the direction of the body by a movable shaft, so that the additional force acting on the suspension is eliminated by controlling the expansion and contraction of the hydraulic cylinder through pressure oil.
Components of the ABC body control system
A1p13—Multi-function display; B22/7—Left rear height sensor; B24/6—Right rear body acceleration sensor; N72/1s3—Comfort/sport switch; B4/5—ABC pressure sensor; B22/8—Left front height sensor; B24/12—ABC lateral acceleration sensor; S9/1—Brake light switch; B22/1—Left rear plunger travel sensor; B22/9—Right front height sensor; B24/14—ABC longitudinal acceleration sensor; X11/4 —Diagnostic connector; B22/4—left front plunger travel sensor; B22/10—right rear height sensor; B40/1—ABC oil temperature sensor; Y36/1—front axle distribution valve unit; B22/5—right front plunger travel sensor; B24/3—left front body acceleration sensor; N51/2—ABC control computer; Y36/2—rear axle distribution valve unit; B22/6—right rear plunger travel sensor; B24/4—right front body acceleration sensor; N72/1s2—height control switch; Y86/1—ABC throttle valve
2.DSC Body Dynamic Control System
The BMW DSC body dynamic control system integrates the ASC automatic stability control system and the traction control system, which can control the slip state of the drive wheels by selectively braking the drive wheels that have a tendency to slip, thereby stabilizing the vehicle accordingly. On icy and snowy roads, deserts or gravel roads, the driver can enter the DTC mode by simply pressing a button, thereby enhancing the vehicle's traction on the above roads. At the same time, since the intervention response limit of the DSC body dynamic control system is slightly extended, the vehicle's traction and driving force are also increased, and the driver can enjoy an extraordinary sports driving experience. Another function of the DSC body dynamic control system is CBC cornering brake control, which can eliminate the vehicle's oversteering tendency through asymmetric braking force control when slightly braking in a turn.
- EBA emergency brake assist device
Under normal driving conditions, most drivers only apply a small force when braking at the beginning, and then increase or adjust the braking force applied to the brake pedal according to the actual situation. However, if a much larger braking force must be applied suddenly, or the driver reacts too slowly, this method will prevent them from applying the maximum braking force in time. This is where EBA comes in.
EBA understands the driver's braking behavior by the rate at which the driver steps on the brake pedal. If EBA detects a panic increase in brake pressure on the brake pedal, it will activate full braking force within a few milliseconds, much faster than most drivers move their feet. EBA can significantly shorten emergency braking distances and help prevent rear-end collisions in stop-and-go traffic.
- EBD Electronic Brake Force Distribution Control
When the car brakes, if the conditions under which the four tires adhere to the ground are different, for example, the left wheel adheres to a slippery road surface, while the right wheel adheres to a dry road surface, the friction between the four wheels and the ground is different, and when braking (the braking force of the four wheels is the same), it is easy to cause slippage, tilting, and rollover.
The function of EBD is to calculate the friction value of the four tires due to different adhesion at high speed at the moment the car brakes, and then adjust the brake device so that it can be adjusted at high speed during movement according to the set program to achieve a match between the braking force and the friction force (traction) to ensure the stability and safety of the vehicle.
When the wheels are locked during emergency braking, EBD has already balanced the effective grip of each wheel before ABS is activated, which can prevent tail swinging and lateral movement and shorten the braking distance of the car. EBD is actually an auxiliary function of ABS, which can improve the effectiveness of ABS.
- EDS electronic differential lock
EDS electronic differential lock is an extended function of ABS, which is used to identify whether the wheels of the car have lost ground friction, so as to control the acceleration and slipping of the car. Compared with ordinary vehicles, vehicles with EDS can better utilize ground adhesion, thereby improving the vehicle's running performance, especially on inclined roads, where the role of EDS is more obvious. However, it has a speed limit and will only start when the speed is less than 40km/h, mainly to prevent slipping at start and low speed.
- ESP electronic stability system
The function of ESP electronic stability system is usually to support ABS and ASR (drive anti-skid system, also known as traction control system). It helps the vehicle maintain dynamic balance by analyzing the vehicle driving status information transmitted from each sensor and then sending correction instructions to ABS and ASR. ESP can keep the vehicle in optimal stability under various conditions, and the effect is more obvious in the case of oversteering or understeering.
ESP generally requires the installation of steering sensors, wheel sensors, side slip sensors, lateral acceleration sensors, etc. ESP can monitor the driving status of the car and automatically apply braking force to one or more wheels to keep the car running in the normal lane, and even brake 150 times per second in some cases.
7.TCS traction control system
TCS traction control system, also known as tracking control system. Its function is to detect the limit of tire adhesion to the ground, and automatically reduce or cut off the power transmitted to the wheel at the moment when the tire is about to slip, so that it can maintain tracking. When a car brakes on a smooth road, the wheels will slip and even lose control of the direction. Similarly, when the car starts or accelerates sharply, the drive wheels may also slip, and on slippery roads such as ice and snow, the direction may also be out of control and dangerous. TCS is designed for this problem.
When TCS relies on electronic sensors to detect that the speed of the driven wheel is lower than that of the driving wheel (this is a characteristic of slipping), it will send a signal to adjust the ignition timing, reduce the valve opening, reduce the throttle, downshift or brake the wheel, so that the wheel will no longer slip. TCS can improve the driving stability of the car, improve acceleration, and improve climbing ability. If TCS is used in conjunction with ABS, the safety performance of the car will be further enhanced. TCS and ABS can share the wheel speed sensor on the axle and connect to the driving control unit to continuously monitor the speed of each wheel. When slipping is detected at low speed, TCS will immediately let ABS act to reduce the slip of this wheel. If slipping is detected at high speed, TCS will immediately send a command to the driving control unit to instruct the engine to slow down or the transmission to downshift, so that the slipping wheel will no longer slip and prevent the vehicle from losing control and drifting.
