The intake system of EFI motorcycle is composed of air filter, intake temperature sensor, intake pressure sensor, throttle body, idle speed control valve and intake manifold. The driver operates the throttle valve opening through the throttle handle to change the intake volume and control the engine operation. After filtering dirt and other impurities through the air filter, the air entering the engine flows through the intake temperature sensor and intake pressure sensor, and then enters the cylinder through the intake manifold. When the engine is operating at idle speed, part of the air passes through the bypass passage or the idle control valve (or idle motor) to bypass the throttle valve and enter the cylinder.

The air filter is a very important component of the engine air intake system. Its role is to filter the dust and impurities entering the engine air and reduce the engine wear. The function of the intake air temperature sensor is to monitor the temperature of the air entering the cylinder, convert the air temperature into a voltage signal and feed it back to the ecu. Because the change of air temperature will lead to the change of air density and oxygen content in the air. With the change of air density and oxygen content, the fuel injection quantity should also be adjusted accordingly. The ECU judges the air density and oxygen content through the change of the electrical signal fed back by the air inlet temperature sensor to correct the fuel injection quantity.

The intake pressure sensor detects the positive pressure of the intake manifold behind the throttle valve. It detects the change of the positive pressure in the manifold according to the size of the engine speed and load, and then converts it into a voltage signal and sends it to the ecu. The ecu changes the fuel injection volume of the control base according to the size of the voltage signal.

The EFI vehicle is an air controlled fuel, which means that the engine computer controls the fuel injection quantity according to the air volume. Therefore, the intake pressure sensor is a very important sensor, and its quality will directly affect the working function of the engine.

Article source: Sailivu Electronic Technology www.sailifu.cn