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Homogeneous Charge Compression Ignition (HCCI) has the potential of reducing fuel consumption as well as NOx emissions. However, it is still confronted with problems in real-time control system and control strategy for the application of HCCI, which are studied in detail in this paper. A CAN-bus-based distributed HCCI control system was designed to implement a layered close loop control for HCCI gasoline engine equipped with 4VVAS. Meanwhile, a layered management strategy was developed to achieve high real-time control as well as to simplify the couplings between the inputs and the outputs. The entire control system was stratified into three layers, which are responsible for load (IMEP) management; combustion phase (CA50) control and mechanical system control respectively, each with its own specified close loop control strategy. The system is outstanding for its explicit configuration, easy actualization and robust performance.

An experimental study has been carried out on the multiple fuel injection process and its effect on the mixing and combustion in a single cylinder diesel engine with optical access. The engine is equipped with a production type cylinder head and a high pressure common rail fuel system which comprises a directly driven high pressure fuel pump and a control system capable of 8 injections per stroke. The single cylinder optical engine could be operated lubrication-free for up to 5 minutes due to the application of special coating on the piston liner and careful design of the piston and extended cylinder block. The in-cylinder spray and combustion were visualized at 10,000 fps by a high-speed colour video camera and a copper vapour laser. The high-speed video recordings and in-cylinder pressure and heat release analysis for up to four fuel injections will be presented and discussed.