What is the structure and working principle of the sensor?

1. Steering wheel angle sensor, used to detect the middle position, rotation direction, rotation angle and speed of the steering wheel.

In electronically controlled suspension, ECU judges the magnitude and direction of lateral force when the car turns according to the signals of angle sensor and speed sensor, thus controlling the roll of the car body.

On the steering shaft of the steering wheel, a light shielding disc (a disc with a narrow slit) is installed, and the photoelectric element (light emitting diode) and photosensitive receiving element (phototransistor) of the sensor are installed on both sides of the light shielding disc. Because the slits on the mask are evenly distributed at equal intervals, when the rotating shaft of the steering wheel drives the disc to deflect, the slit disc will sweep the air gap in the middle of the photoelectric element, thus making on-off conversion at the output end of the sensor and forming a pulse signal.

When the steering wheel rotates, the light beam between photoelectric elements changes on/off, and the repeated on/off state of photoelectric elements will produce a series of digital signals proportional to the steering shaft angle, and ECU can judge the steering wheel angle and speed according to the changes of these signals. At the same time, the sensor adopts two groups of photoelectric couplers in structure, which can judge the steering wheel deflection direction according to the phase difference of the detected pulse signals. This is because the on-off conversion phases of the two pairs of photoelectric couplers are staggered by 90 degrees during installation, and the deflection direction of the steering shaft can be detected by judging which pair of photoelectric couplers is connected first. For example, when turning left, the left photoelectric coupler always reaches the ON state before the right photoelectric coupler; When turning right, the right photoelectric coupler always reaches the ON state before the left photoelectric coupler.

2. Acceleration sensor, when the wheel slips, it is impossible to correctly judge the lateral force of the car body through the steering angle and vehicle speed. In order to directly measure the lateral acceleration and longitudinal acceleration of the car body, an acceleration sensor is needed.

The lateral acceleration sensor is mainly used to detect the lateral acceleration caused by the centrifugal force when the car turns, and send the generated electrical signal to the ECU, so that the electronic control unit can correctly control the change of the damping coefficient of the suspension system and the adjustment of the air pressure in the air spring to maintain the best posture of the car body.

3. Body height sensor

The function of the body height sensor is to detect the change of the body height (the displacement of the automobile suspension) when the automobile is running, and convert it into an electrical signal and transmit it to the ECU of the suspension system. The body height sensor is fixed on the frame, and the outer end of the sensor shaft is equipped with a guide rod, and the other end of the guide rod is connected with the lower swing arm of the independent suspension through a connecting rod.

4. Throttle position sensor

Suspension control system uses the signal of throttle position sensor to judge whether the car is accelerating rapidly. The throttle position sensor first inputs the signal to the engine ECU, and then the engine ECU inputs the signal to the suspension ECU.

5. Vehicle speed sensor,

6. Mode selection. The switch mode selector switch is located next to the transmission control handle. The driver chooses the working mode of the suspension according to the driving situation and road conditions of the car, thus determining the damping coefficient of the shock absorber.

Vehicle speed is a common control signal of automobile suspension system, and the roll degree of automobile body depends on vehicle speed and steering radius. Through the detection of vehicle speed, the damping coefficient of electronically controlled suspension can be adjusted, thus improving the safety of vehicle driving.