Circuit Description

Direct Injection Engine has the system, which injects the fuel into the cylinder directly. The fuel is supplied from the low pressure pump is sent to the high-pressure pump and is pressurized to 5-10 MPa in the high-pressure pump. The fuel is injected into the cylinder with this high pressure. The fuel injector is a kind of the solenoid operated valve and ECM controls the pulse width.

ECM also controls the high-side fuel pressure by the duty signal, which controls the pressure regulator. The fuel pressure sensor is located on the fuel rail and ECM monitors the signal from this fuel pressure sensor. The duty signal, which controls the pressure regulator, is decided base on the signal from the pressure sensor.