The Sensors of Engine

The engine sensor control system is the core of the entire automotive sensor. It has many types, such as temperature transmitter, pressure sensor, position and speed sensor, flow sensor, oxygen sensor, and knock sensor. These sensors provide the engine's electronic control unit (ECU) with information about the engine's working condition for the ECU to accurately calculate and control the engine's working condition to improve engine power, reduce fuel consumption and exhaust emissions as well as perform fault detection.

1. The temperature sensor is mainly used to detect the temperature of engine, intake air, cooling water, fuel, and catalyst.

2. The flow sensor is mainly used for the measurement of engine air flow and fuel flow. The function of the air flow sensor is to convert the amount of air drawn into the engine cylinder per unit time into an electrical signal and send it to the engine control module (ECU). It is one of the basic signals that determine the amount of fuel injection and ignition timing, and is used for engine control system to determine the combustion conditions and control air-fuel ratio, start-up, ignition, etc.

3. Position and speed sensors are mainly used to detect crankshaft angle, engine speed, throttle opening, vehicle speed, etc. At present, the position and speed sensors used in automobiles mainly include alternator type, magnetoresistive type, Hall effect type, reed switch type, optical type and semiconductor magnetic transistor type, with a measurement range of 0° to 360°, an accuracy of ±0.5 below and the measured bending angle of ±0.1.

4. Pressure sensors are mainly used to detect negative cylinder pressure, atmospheric pressure, the boost ratio of turbo engine, internal pressure of cylinder, oil pressure, etc, including liquid level pressure sensor, hydrogen pressure sensor.

5. The oxygen sensor is used to detect the state of the exhaust gas entering the three-way catalytic converter and is an indispensable sensor on the engine using the three-way catalytic converter. There are two types of oxygen sensors, zirconia type and titanium oxide type, which have been used in automobiles.

6. Knock sensor is used to detect the abnormal phenomenon of spontaneous combustion produced by the final mixture in the combustion chamber. As knocking will produce a high-intensity pressure wave that impacts the combustion chamber, which will not only make a sharp metal sound but also have a great impact on the components of the engine. Premature ignition is the main cause of knocking. In order to make the engine run at maximum power, it is best to advance the ignition time to the limit range where the engine just does not knock. Therefore, a knock sensor must be added to the ignition system.