Analysis of common sensors in automobiles
Air flow meter
L-type electronically controlled fuel injection system is used. The air flow meter is installed between the air filter and the throttle body, and it is used to measure the air flow. It can convert the inhaled air volume into an electrical signal and send it to the engine ECU as one of the basic signals to determine the fuel injection volume.
Intake pressure sensor
D-type electronically controlled fuel injection system is used. The intake pressure sensor detects the absolute pressure of the intake manifold behind the throttle. It detects the absolute pressure change in the intake manifold according to the engine speed and load, and then converts it into a signal voltage and sends it to the ECU. The size of the signal voltage controls the size of the basic fuel injection.
Throttle position sensor
It is installed on the throttle body and keeps linkage with the throttle shaft to reflect the different operating conditions of the engine. It is the main signal sensor for idle speed control, starting acceleration control, rapid acceleration control, rapid deceleration control, fuel cut control, ignition advance angle control and automatic transmission shift control.
Crankshaft position sensor
The function of the crankshaft position sensor is to sense the position of the crankshaft angle to determine the reciprocating position of the piston in the cylinder as a reference point for fuel injection timing and ignition timing.
Camshaft position sensor
The camshaft position sensor is also called the cylinder recognition sensor. The function of the camshaft position sensor is to collect the position signal of the valve camshaft and input it into the ECU so that the ECU can identify the top dead center position of a certain cylinder (such as a cylinder) of the engine, so as to perform sequential fuel injection control, ignition timing control and deflagration control.
Temperature Sensor
Mainly detect coolant temperature, intake temperature, exhaust temperature, etc., and convert them into electrical signals to control the opening time and duration of the injector.
Oxygen Sensor
The oxygen sensor is installed on the exhaust pipe and sends a negative feedback signal to the fuel supply system by detecting the oxygen content in the exhaust gas of the car and the air-fuel ratio in the cylinder to correct the fuel injection pulse and adjust the air-fuel ratio to the theoretical value to achieve the ideal exhaust purification Effect.
The knock sensor is installed on the cylinder block and inputs the cylinder pressure or engine vibration signal to the ECU. After being processed by the ECU, the ignition advance angle is controlled to suppress the occurrence of knocking.
Vehicle speed sensor
Used to detect the speed of the output shaft of the automatic transmission. The electronic control unit calculates the vehicle speed based on the signal from the vehicle speed sensor as the basis for shift control.
Input shaft speed sensor
The input shaft speed sensor is used to detect the input shaft speed and send the signal to the ECU so that the ECU can more accurately control the shifting process to improve the shifting feeling and improve the driving performance of the car.
Coolant temperature sensor
When the coolant is lower than a predetermined temperature, if the transmission is shifted into an overspeed gear, the engine performance and the comfort of the vehicle will be affected. To prevent this from happening, the automatic transmission will not shift to the highest gear before the coolant reaches a predetermined temperature (for example, 105°C).
Hydraulic oil temperature sensor
Used to detect the temperature of the hydraulic oil of the automatic transmission, as the basis for the automatic transmission control unit to perform shift control, oil pressure control and lock-up clutch control.
In addition, it also includes various switch signals, such as neutral start switch signal, kick-down switch signal, driving mode switch signal, etc.
Wheel speed sensor
The wheel speed sensor is used to detect the speed of the wheel and transmit the signal of the wheel speed to the ABS electronic control unit. The electronic control unit calculates the reference speed, the speed of each wheel and the deceleration of the car according to this signal, and determines the slip rate of each wheel.
Acceleration sensor (deceleration sensor)
Acceleration sensors are divided into positive acceleration sensors and negative acceleration sensors. Negative acceleration sensors are also called deceleration sensors, or G sensors. It is generally used in four-wheel drive cars, and its function is to obtain the car deceleration signal when the car is braking, so as to identify whether it is a slippery road such as a snowy road or an icy road.
Trigger the collision sensor
The trigger collision sensor is also called the collision intensity sensor, which is used to detect the acceleration change during the collision and transmit the collision signal to the airbag ECU as the trigger signal of the airbag ECU.
Guard collision sensor
The protective collision sensor is also called the safety collision sensor, which is connected in series with the trigger collision sensor to prevent accidental explosion of the airbag.
Torque sensor
The torque sensor continuously measures the torque signal on the steering shaft, and the electronic control unit determines the magnitude and direction of the assist torque according to these input signals, that is, selects the electric current and steering of the motor, and adjusts the magnitude of the steering assist power.
Steering wheel angle sensor
The steering wheel angle sensor is integrated in the clock spring under the steering wheel to detect the middle position, rotation direction, rotation angle and speed signal of the steering wheel. These signals are used in electronically controlled power steering, vehicle stability control, and electronically controlled suspension.
Vehicle height sensor
It is used to detect the change in the height of the car in the vertical direction. The signal can make the suspension control unit feel the change in the height of the car, and adjust the height of the car body through related actuators.
Level sensor
It mainly detects whether the car is in a horizontal state, and provides auxiliary signals for the electronically controlled suspension and the headlight automatic leveling system.
