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Introduction of Automotive Sensors


The vehicle sensor is the input device of the computer system of the car. It converts the information of various working conditions in the running of the car, such as the speed of the vehicle, the temperature of various media, the operating conditions of the engine, etc., into electrical signals and sends them to the computer so that the engine is in the best condition. working status.
Automotive Sensor
basic features

A sensor is a device or device that can sense a specified physical quantity and convert it into a usable input signal according to a certain rule. Simply put, a sensor is a device that converts non-electricity into electricity. The sensor is usually composed of three parts: sensitive element, conversion element and measurement circuit.

1) The sensitive element refers to the part that can directly feel (or respond) to be measured, that is, to convert the measured through the sensitive element of the sensor into a non-electrical or other quantity that has a definite relationship with the measured.

2) The conversion element converts the above-mentioned non-electric quantity into an electric parameter.

3) The function of the measurement circuit is to process and convert the electrical parameters input by the conversion element into measurable quantities such as voltage, current or frequency for display, recording, control and processing.


1. The gasoline indicator is realized by the liquid level sensor. This liquid level sensor uses the level of the liquid level and then converts it into a digital signal, which can be easily read from the instrument.

2. Water temperature sensor, the water temperature sensor is installed in the water tank through the temperature measuring node, when the water temperature is too high or too low, it can also alarm, and can also be read directly from the display instrument.

3. Air conditioner in the car. The air conditioner in the car is controlled by a temperature sensor installed in the car. The temperature sensor has a temperature setting. When the temperature is too low, it will automatically start, and when the temperature exceeds it, it will automatically cool down.

4. The wiper sensor. The wiper senses the size of the rain through the sensor, so as to control the frequency of the wiper.

5. The engine management system uses various sensors to convert the engine intake air volume, cooling water temperature, engine speed and acceleration and deceleration into electrical signals and send them to the controller. The controller compares these information with the stored information and outputs control signals after accurate calculation. EMS can not only precisely control the fuel supply to replace the traditional carburetor, but also control the ignition advance angle and idle air flow, which greatly improves the performance of the engine.

6. Control system principle: through the pedal sensor installed on the accelerator pedal, the pedal information is transmitted to the throttle control module in the electronic controller, and the throttle control module calculates the opening of the throttle through a certain processing program and drives the DC The motor completes the adjustment of the intake channel area of the throttle valve, thereby controlling the intake air volume and meeting the intake air demand of the engine under different working conditions.

7. Knock sensor function: detect the vibration of the engine cylinder for the electronic controller to identify the engine knock condition. Principle: The knock sensor is a vibration acceleration sensor. It is installed on the cylinder block of the engine, and one or more can be installed. The sensitive element of the sensor is a piezoelectric crystal. When the engine knocks, the engine vibration is transmitted to the crystal through the mass in the sensor. Due to the pressure generated by the vibration of the mass block, the piezoelectric crystal generates voltage on the two polar surfaces, and converts the vibration into a voltage signal for output.

8. Idle speed regulator function: provide idle speed bypass air channel, and affect the bypass air volume by changing the cross-sectional area of the channel, so as to realize the closed-loop control of the engine speed at idle speed.

9. Oxygen sensor function: measure the oxygen content in the engine exhaust, and determine whether the gasoline and air are completely combusted. Based on this information, the electronic controller realizes the closed-loop control aiming at the excess air coefficient λ=1, so as to ensure that the three-way catalytic converter has the maximum conversion efficiency for the three pollutants of HC, CO and NOX in the exhaust.