The Cummins fuel system mainly consists of the PT fuel system and the common rail fuel system. The following is a detailed introduction:
PT Fuel System
Components: Primarily composed of a fuel tank, fuel filter, PT fuel pump, low-pressure fuel line, injectors, rocker arms, pushrods, injector cams, and return lines. For turbocharged diesel engines, the PT fuel pump also includes an exhaust smoke limiter.
Working Principle: PT is an abbreviation for pressure and time, meaning it regulates fuel injection quantity based on the pressure-time principle. The PT fuel pump is a low-pressure fuel pump that serves a dual function of supplying fuel and adjusting pressure. It draws fuel from the fuel tank and pressurizes it to the injectors. Simultaneously, it adjusts the outlet fuel pressure according to changes in diesel load and engine speed, thus changing the injector's fuel injection quantity. The injectors meter the fuel injection based on the PT fuel pump's outlet fuel pressure, and then, relying on an injector plunger drive mechanism, pressurize the fuel and inject it into the combustion chamber at specified times. Remaining fuel returns to the fuel tank via the return line.
Common Rail Fuel System
Components: Primarily consists of a fuel tank, fuel pump, fuel filter, common rail, injectors, various sensors, and an electronic control unit (ECU).
Working Principle: The fuel pump draws fuel from the fuel tank, pressurizes it, filters it through the fuel filter, and delivers it to the common rail. The common rail stores the fuel and maintains a certain pressure, ensuring a stable pressure supply to the injectors at each injection point. The ECU precisely controls the injector's opening timing, injection quantity, and injection frequency based on engine operating conditions and sensor feedback, achieving precise control of fuel injection.
