[4] Rail Pressure Sensor The rail, the rail pressure sensor is mounted on the rail and detects the fuel pressure. It is a semi-conductor type of pressure sensor that utilizes the properties of silicon to change its elec- trical resistance when pressure is applied. VPC 5 A-VCC ECU Output voltage (V) 4 +5V 3 VPC 2 A-GND 1 0 Pressure PC (MPa) 50 100 150 Q000095E 2.3 Injector [1] Outline The function of the injector is to inject high-pressure fuel from the rail into the engine combus- tion chamber at the proper timing, quantity, ratio, and atomization, in accordance with signals from the ECU.
The TWV (two-way solenoid valve) regulates pressure in the control chamber in order to control the beginning and end of injection. The orifice restrains the opening speed of the nozzle valve to regulate the injection ratio. The command piston transmits pressure from the control chamber to the nozzle needle valve. The nozzle atomizes the fuel. Start of Injection (TWV ON) End of Injection (TWV OFF) Rail pressure sensor TWV Rail pressure sensor TWV ECU Rail Leak ECU Rail Leak Orifice Orifice Control chamber Control chamber Supply pump Command piston Supply pump Command piston Injection pressure control Injection pressure control Nozzle Nozzle Q000096E 10