(1) Coolant temperature sensor structure
The coolant temperature sensor is a negative temperature coefficient resistance meter NTC, and the interior is composed of a semiconductor thermistor, which has a negative temperature coefficient NTC.
When the temperature of the engine coolant gradually increases, the resistance of the thermistor will gradually decrease, and on the contrary, it will increase. As a result, the output voltage of the sensor changes accordingly when the temperature of the engine coolant changes.
The function of the coolant temperature sensor is to give a signal to the electronic fan relay according to the engine water temperature so that it can connect to the electronic fan circuit to work, and the electronic fan has the low-speed gear and high-speed gear. high gear. If it is broken, the electronic fan will keep rotating and maintain in a rotating state (low-speed gear), so it is easy for the water temperature to be high, and in severe cases, the heat dissipation will be poor, and the water temperature warning light will be on.
When the ECU cannot find the normal signal of the coolant temperature sensor, in order to keep the engine running, the engine ECU will perform the safety function. At this time, the engine ECU takes the coolant temperature substitute value (80℃～90℃) stored in its memory as the coolant temperature value.
(2) Characteristics of coolant temperature sensor
The coolant temperature sensor is a negative temperature coefficient resistance meter NTC, and its resistance value will decrease as the temperature increases. By measuring its voltage value, the DME can calculate the size of the resistance, thereby deriving the coolant temperature. The coolant temperature sensor has 2 PIN pins, PIN1 is the signal line, and PIN2 is the ground line.
(3) Coolant temperature sensor function
The coolant temperature sensor is used to detect the temperature of the engine coolant, and transmit this signal to the electronic control element (ECU) of the engine, and adjust the injection time, ignition timing, and idle speed according to the signal, and can also be used as other Control signals for the control system. The effects of engine coolant temperature sensor failure are as follows.
①When the coolant temperature sensor fails, there will be a fault memory, and the engine cannot accurately calculate the fuel injection amount; the engine will shake or emit black smoke, and the power and economy of the engine will be affected.
②The engine cannot accurately calculate the theoretical idle speed, and the idle speed of the engine will be unstable.
③ When the engine coolant temperature sensor has an open circuit or short circuit fault, the electronic fan will rotate at a high speed.
Look through Easybom to learn more about the coolant temperature sensor.
