First, the composition
    China-made 2008 MAGOTAN 1.8TSI sedan with turbocharged gasoline direct injection technology, MAGOTAN 1.8TSI car fuel control system mainly by the electric pump, with pressure limiting valve filter, low pressure fuel pressure sensor G410, fuel high pressure pump, fuel pressure regulator Valve N276, high pressure fuel pressure sensor G247, fuel rail, pressure limiting valve, injector, engine control unit ECU and fuel pump control unit J538 and so on. The schematic diagram shown in Figure 1, fuel system components installed as shown in Figure 2.
    Second, the working principle
    MAGOTAN 1.8TSI sedan engine using gasoline cylinder direct injection technology, fuel system through the fuel high-pressure pump (driven by the axle) low-pressure fuel system 50 ~ 650kPa low-pressure fuel into 1.1 ~ 3.0MPa high-pressure fuel to meet different conditions The demand. Fuel pressure regulating valve N276 installed in the fuel high-pressure pump, is a high-frequency solenoid valve. The engine control unit controls the N276 to precisely adjust the duty cycle according to the signal monitored by the high pressure fuel pressure sensor G247 mounted on the high pressure rail to obtain the desired fuel pressure. The pressure of the low-pressure fuel system is provided by the electric fuel pump in the fuel tank. The fuel pump control unit J538 installed in the upper part of the fuel tank controls the electric fuel pump according to the pulse width modulation signal (fuel control circuit shown in Figure 3) So that low-pressure fuel system pressure maintained at 50-500kPa. In the engine start, low-pressure fuel system pressure can reach more than 600kPa, to ensure the normal start and work of the engine.
    High pressure pump
    The high pressure pump produces a pressure of about 150 bar (1 bar = 10 sPa). The pump piston is driven by the camshaft through the cylindrical tappet, which reduces the friction and reduces the chain force so that the engine is running more smoothly and the fuel economy is better. The high pressure pump is shown in Fig.
    (1) into the oil
    In the process of oil, the oil valve in the needle under the action of spring force to open. In the process of moving down the piston of the high-pressure pump, the volume of the pump chamber is increasing, and the fuel pressure in the pump chamber is similar to that in the low-pressure system. As shown in Figure 5.
    (2) oil supply
    The control unit ECU calculates the fuel supply start point to send a command to the fuel pressure control valve N276 to suck it. The needle valve will overcome the force of the needle valve spring to the left: the oil inlet valve is closed under the spring force to move the pump upward movement, the pump chamber to establish the oil pressure. When the oil pressure in the pump chamber is higher than the oil pressure in the oil rail, the oil is opened and the fuel is pumped into the oil rail as shown in Fig.
    2 fuel pressure sensor
    The constant pressure in the rails has a significant impact on reducing emissions, reducing noise and increasing power. The fuel pressure is adjusted in an adjustment circuit, and the measurement error of the sensor is less than 2%. The core of the sensor is a steel film, coated with a strain resistance on the steel film to measure the pressure through the pressure interface to the side of the steel membrane, the steel film bending. It causes the resistance of the strain resistance to change. The sensor has a set of electronic analysis mechanism, as shown in Figure 7.
    3 fuel pump control unit J538
    Fuel pump control unit J538 installed in the electric pump above, as shown in Figure 8. Its role is mainly through the pulse width modulation signal (PWMpulse-widthmodulated) to control the electric fuel pump, so that low-pressure fuel system hydraulic pressure to 0.5 ~ 5bar. In the hot and cold start when the pressure of low-pressure fuel system to 650 kPa or so.
    4 high pressure injector
    High-pressure injector As shown in Figure 9, the main role of high-pressure injector is to make the fuel to form a fine mist; the correct measurement of the amount of fuel; the fuel is accurately sprayed into the corresponding area of ​​the combustion chamber; at the right time the fuel is directly pressed into the combustion room.