Electric feed pump – supplies fuel to the high pressure pump. Fuel Filter – it is vital that this is replaced in line with manufacturer’s recommendations to ensure system cleanliness and lifespan. Overflow valve – enables excess fuel to overflow back into the fuel tank. Return manifold – controls the return of fuel back to the fuel tank. High Pressure pump – the high pressure pump is the heart of the fuel system. This is where diesel fuel has its pressure increased, It is engine driven. How it works: The high pressure pump compresses the fuel and delivers it’s under pressure of up to 2000 bar to the high pressure rail. The pump is equipped with a metering unit for fuel delivery control. The high pressure rail serves as a high pressure storage unit, injection pressure is controlled with the help of the metering unit and the pressure regulator valve operated as a double actuated system. The injectors are the key components required for the system. They feature quick switching pressure regulated solenoid valve. Therefore high injection pressure, short interval between injection and integrated high pressure volume in the injector give engine producers great flexibility, and the results are economy and diversity of the system, reduced emissions and combustion noise, reduced pressure pulsation and optimised injection process, higher efficiency and co2 optimization by reduced return flow. The injectors are also suitable for use with sub optimal fuel quality. The ECU contributes to the high precision of the injection, controlling the high pressure pump and the injectors.
In the common rail system, fuel is distributed to the injectors from a high pressure accumulator, called the rail. The rail is fed by a high pressure fuel pump. The pressure in the rail, as well as the start and end of the injection in each cylinder are electronically controlled. Advantages of the common rail system Include flexibility in controlling both the injection timing and injection rate. Stable pilot injections which can be delivered by the common rail have proven to lower the engine noise and the CO2 emissions. Pilot fuel injection is defined as a pre-injection of a small quantity of fuel 5 to 20 crankshaft degrees before the main fuel injection. This pre-injection softens the main injection pressure rise and reduces combustion
Characteristics involve: · low fuel consumption, but more power to the engine · It is used in passenger cars with 3-8 cylinder engines · It is a quick start capable system · Increased pressure level up to 2000 bar
Published on Jan 7, 2014