Numerical Study On High Pressure Common Rail Injection System Of Diesel Based On The GT-SUITE

With the implementation of more stringent emission regulations, new technologies that can reduce the emission of engine are impressive, high pressure common rail fuel injection system is one of a kind. High pressure common rail fuel injection system is the technologies that can reduce the emission of engine, which has been proved by practice, but this technology currently is controlled in the hands of a few big companies in foreign countries. The research in china is still at an early stage, therefore, it is necessary to research it.GT-FUEL and GT-POWER are the parts of the GT-SUITE series software, the high pressure common rail fuel injection system model and four-valve diesel engine model are respectively established by GT-FUEL and GT-POWER, then the two models are coupled in the GT-SUITEflow platform, thus a coupled model is established. And then in order to verify the accuracy of the model, a comparison of the experimental data and simulation data is done.Taking into account modern piezoelectric injectors has been able to solve the response problem of the solenoid valve injectors, a injector hydraulic system model is established to study how to improve injector's hydraulic response. The process of fuel injection is controlling by the oil hole open-closed.This paper study injection rate, dynamic pressure characteristics and dynamic response characteristics of high pressure common rail fuel injection system respectively, and believes that the combination of the three characteristics can fully reflect the performance of the system. Then the influence of the key structure parameters on the fuel injection rate, dynamic pressure characteristics and dynamic response characteristics of common rail system is studied by using the injection system model which established in the GT-FUEL. The key structure parameters are control chamber, needle mass, diameter and number of nozzle hole, flow coefficient of nozzle hole, diameter of Z-throttle, diameter of A-throttle and etc. A reasonable size of the parameters is determined based on the research. Then a improved design and simulation are done because of the longer close time of the needle valve after change the structure parameters, the results indicate that the improved injector can significantly shorten the close time of the needle valve.Lastly, this paper study the influence of common rail pressure and fuel injection timing on fuel injection system and economy, power and emissions of engine by this coupled model. This study provides a basis for the select of parameter value. Results indicate that:the value of the common rail pressure is not the bigger the better, the value should firstly satisfy the limit request of the NOx emissions and the injection quantity requirements; the value of the fuel injection timing should choose an appropriate value under the premise of first meet the NOx emission limit values.