Research On Medium Pressure And Common Rail Hydraulically Intensified Electronically Controlled Fuel Injection System For Diesel Engine

The common-rail (CR) electronically controlled fuel injection system is one of the most effective technologies to enhance the engine performance and reduce harmful matter, By analyzing several kinds of advanced electronically controlled fuel injection system, a new kind of medium pressure and common-rail hydraulically intensified electronically controlled fuel injection system of diesel was developed in this paper. In the new system, lubricating oil as working medium was used for fuel intensification and injection. The additional mechanism isn't needed and injector isn't changed. Through the usage of the Independent development solenoids the precise control of injection process were realized successfully. The independent controlling of the injection pressure could be realized. In this system, the adjustment of the injection quantity could be realized through the controlling of the pressure in the common-rail system and the dwell time of solenoid, to meet the need of the diesel.At first, an electronically controlled hydraulically intensified pump, a common-rail hydraulically actuated device and an ECU were developed, then, the whole system and its test bed were developed.The testing results of the new system's injection performance show the features of adjustable injection pressure, injection quantity and injection time.Using the calculating method of model units, the simulating model of medium pressure and common-rail hydraulically intensified electronically controlled fuel injection system was developed. Using this model, the injecting process of this system was simulated and analyzed. The effects of some important constructive parameters, for example, the flow area of the solenoid valve, the ratio of the intensifier's area, the flow area of the nozzle etc, were analyzed. The degree and the law of their effect on the system's performance were researched. By using these models to calculate and analyze the injectingprocess with different parameters, it will provide the valuable basis for improving and perfecting the medium pressure and common rail hydraulically intensified electronically controlled fuel injection system.Finally, some conclusions about the development of the electronically controlled fuel injection system were summarized and some ideas about how to reform the system were provided.