The engine intake temperature sensor uses a negative temperature coefficient thermistor, which generates different signal voltages according to the resistance change. It is used to detect the intake air temperature, convert it into a voltage signal and input it to the ECU as a fuel injection correction signal. Except for the Karman scroll air flow sensor, all other engines are equipped with an intake air temperature sensor. The intake air temperature sensor can be installed in the air flow sensor or the intake pressure sensor, or it can be installed in a certain part on the intake port. When the engine intake temperature is high, the control unit will reduce the fuel injection pulse width, and conversely increase the fuel injection pulse width.