![]() ![]() The common rail system is an alternative to mechanical injection pumps and HEUI systems, both of which lack the inherent ability to realize higher injection pressures and the ability to fire an injector multiple times per single combustion event. The most important factor in a common rail system is rail pressure greater rail pressure yields greater atomization of fuel and is therefore closely related with combustion efficiency. ![]() When this occurs, fuel flows through the injector nozzle where it atomizes as it enters the combustion chamber. Injection events are commanded by the PCM/ECM, which energizes an injector in order to initiate an injector event. The "rail pressure", or pressure of the fuel system at the outlet of the high pressure pump, can reach pressures in excess of 30,000 psi. The high pressure pump maintains tremendous pressure within the common rail(s) an I-6 engine features a single common rail that feeds each injector, while a "V" engine will utilize two common rails, one for each engine bank. The lift pump's only purpose is to consistently provide fuel to the injection pump - the pressure of the fuel as it enters the injection pump is small and has no effect on the actual injection pressure. A common rail system is comprised of a low pressure fuel pump (lift pump), high pressure fuel pump (injection pump), Piezo electric fuel injectors, and the associated rail system.įuel is delivered from the fuel tank to the injection pump via the lift pump. The configurations superior performance characteristics and relatively high injection pressures reduce emissions while improving efficiency. High pressure common rail injection systems, or simply common rails, are the injection type of choice for modern diesel engines. Due to relatively high injection pressures and greater control over injector events, common rail injection systems feature favorable performance characteristics and lower emissions. The high pressure common rail is the injection type of choice for modern diesel engines, far surpassing the capabilities of mechanical and hydraulic injection systems of years past. ![]() The original article can be found here - if you’d like to read the article there, or I’ve pasted parts of it here to share it. Today I found a great article in Diesel Hub that I know many of you will enjoy reading or possibly relate to. ![]() On engine over-run only the first pilot injection phase remains.Hi everyone. With the engine running at a higher speed, the pilot and main injection events all occur within a shorter total time period and their peak currents increase with increased alternator output at higher engine speeds. When the accelerator pedal is depressed and there is a demand for increased engine torque and the main injection duration increases to around 900 µs. The main injection duration is around 450 µs. The pilot injection durations are around 250 to 350 µs. The pulses have peak amplitudes around /- 7 A and cycle from 0 A to their peak value and back within 100 to 200 µs (the precise values will vary with system and test conditions).ģ x pairs of pulses, indicating two pilot injections and one main injection: One or more pairs of positive and negative pulses, which respectively drive the opening and closing of the injector. These known good waveforms have the following characteristics:
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