● Basic introduction of engine sensor
Sensors on electronically controlled diesel engines can be described as diverse. The sensor types are roughly divided into three categories: pressure sensors, temperature sensors, speed and position sensors. There are about ten types of subdivided types. Today I will introduce you to diesel engines. Sensors.
This includes: oil pressure and temperature sensor, temperature sensor, intake air temperature sensor, coolant temperature sensor, fuel pressure and temperature sensor, engine speed sensor, engine position sensor, camshaft position sensor, crankshaft position sensor, etc. more than ten kinds of sensors . And what I want to introduce below is the necessary sensors for most electronically controlled diesel engines.
● Crankshaft speed sensor
Structure: Magnetic pulse type
Function: The speed sensor collects the diesel engine speed signal so that the ECU can calculate the circulating fuel supply. It can also provide the crankshaft position signal so that the ECU can accurately control the fuel injection timing; the auxiliary speed sensor is used as the speed signal to calculate the crankshaft angle signal to judge the cylinder .
Installation location: On the flywheel housing and on the supply pump
● Camshaft position sensor
Structure: Magnetic winding method
Function: Each revolution of the camshaft provides a signal to the ECU, and the ECU determines that the piston of that cylinder is at the top dead center of the compression stroke.
Installation position: at the front end of the camshaft
● Common rail pressure sensor
Structure: Piezoresistive high pressure sensor, the highest frequency is 1KHz, the measurement range is 0-200Mpa
Function: real-time measurement of the actual pressure signal in the common rail pipe and feedback to the ECU to increase or decrease the oil pressure
Installation position: on the common rail pipe
● Coolant sensor
Structure: Thermistor with negative temperature, its use range is 40-130°C
Function: Mainly used to measure the temperature of the engine cooling, so as to further accurately control the fuel injection volume
Installation position: on the thermostat body
● Intake air pressure sensor
Structure: Semiconductor piezoresistor pressure sensing body. Function: Calculate the air volume and use the thermistor to control the air-fuel ratio and negative temperature to further accurately control the fuel injection volume.
Installation location: installed in the intake manifold
● Fuel temperature sensor
Structure: The thermistor with negative temperature, its use range is -40-130°C.
Function: Used to provide fuel temperature signal to the engine control unit, generally set in the second-stage fuel filter cover. The engine control unit corrects the fuel injection volume according to the temperature change of the fuel, because the fuel expands and becomes less dense as the temperature rises.
Location: On the main oil pipe
● Oil temperature sensor
Structure: Thermistor with negative temperature breakdown
Function: Used to provide the engine oil temperature to the engine control unit, especially in cold conditions.
Location: On the main engine oil pipe
● After the conclusion
With the popularization of EFI diesel engines, the role of electronic control systems on diesel engines is becoming wider and wider. As the engine’s “ears”, the sensors are all over every detail of the engine, monitoring its working status at all times. Therefore, in daily life, don’t ignore their important role because of their smallness.