Abstract: On the basis of 20T high pressure common rail diesel engine and Bosch second generation high pressure common rail fuel injection system, the starting control strategy is formulated, and the parameters of starting control strategy including starting adjustment torque constant, fuel injection proportion and injection timing are optimized by tests in the condition of constant fuel quantity injected. The results show that when the starting adjustment torque constant is set to 25N·m, the combustion and heat release centers of gravity are in the vicinity of top dead center, leading to a sufficient combustion of fuel. As the fuel injection proportions of two preinjections and one maininjection are set to 20%-20%-60%, the starting time can be shortened and the maximum cylinder pressure in starting process is more stable. The optimal injection timing is determined by orthogonal experiment, effectively reducing the mean square deviation of maximum cylinder pressure in starting cycle and enhancing the thermal efficiency of the first starting cycle. After engine is optimized, the starting time is shortened, the smoothness and stability of starting are improved, the fuel burns more sufficiently, thus resulting in an overall enhancement in starting performance of engine.

Key words: high pressure common rail diesel engine, starting control strategy, parameter optimization, orthogonal experiment