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what sensor controls the speedometer
The vehicle speed shall be displayed in the vehicle instrument system; The vehicle speed is involved in the fuel injection, automatic transmission, ABS/ASR, cruise control and other systems. The vehicle speed is usually calculated by directly or indirectly detecting the rotational speed of automobile tires.
Functions: Detect the driving speed of the vehicle, and input the detection results to the vehicle instrument system to display the speed; Or input the detected vehicle speed signal to the ECU of the vehicle control system that needs the vehicle speed signal.Type of vehicle speed sensor : The types of vehicle speed sensors are: reed switch type, electromagnetic induction type, photoelectric type, variable reluctance type, Hall type, etc
The speed sensors are as follows:
1.Photoelectric speed sensor, magnetoelectric speed sensor, Hall speed sensor, etc., many of them can be used to directly measure the speed, or the speed can be obtained by converting the displacement sensor;
2. Many sensors are equipped with display instruments and relays, which can easily count;
3. Vibration measurement can directly use vibration sensors, and can also use various displacement sensors to measure medium, low and high frequency vibration. There are speed sensors for indirectly measuring speed, such as acceleration sensor, displacement sensor, etc. The tachogenerator and some magnetoelectric sensors can directly measure the speed through AC RMS conversion in the linear region; Most output pulse signals. There are many. Acceleration sensors, angular velocity sensors, angular velocity sensors (gyroscopes), magnetoresistive sensors may also be used to measure speed. Microwave, laser, infrared, and ultrasonic can be used to measure speed. You can learn about sensors on the sensor expert network. The structure and principle of the photoelectric speed sensor are basically the same as those of the crankshaft or camshaft photoelectric position sensor, and the detection method is similar. The sensor generates 20 pulses every revolution of the speedometer flexible shaft. Principle of photoelectric speed sensor Circuit block diagram of speedometer. The deceleration sensor, also known as G sensor, is usually used in ABS/ASR and other systems related to vehicle driving and braking control of four-wheel drive vehicles. When braking on roads with high adhesion coefficient, the deceleration is large, and when braking on roads with low adhesion coefficient, the deceleration is small. When driving on roads with low adhesion coefficient, such as snow and icy roads, corresponding measures shall be taken to improve the braking performance. When a car is running with low adhesion coefficient, its driving wheels usually slip. On a two wheel drive vehicle, the ECU of the ABS system can judge the slip of the driving wheels according to the signal from the wheel speed sensor. ABS system will adopt different anti lock braking modes on different road surfaces with different adhesion coefficients.
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