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In this paper an estimation method on location of peak pressure (LPP) employing flame ionization measurement, with the spark plug as a sensor, was discussed to achieve combustion parameters estimation at quick start of HEV engines. Through the cycle-based ion signal analysis, the location of peak pressure can be extracted in individual cylinder for the optimization of engine quick start control of HEV engine. A series of quick start processes with different cranking speed and engine coolant temperature are tested for establishing the relationship between the ion signals and the combustion parameters. An Artificial Neural Network (ANN) algorithm is used in this study for estimating these two combustion parameters. The experiment results show that the location of peak pressure can be well established by this method.

A novel method is applied to analysis the autoignition phenomenon. Experiments on the study of autoignition characteristics of diesel fuel were carried out with a Controllable Active Thermo-Atmosphere Combustor. The results show that the method for autoignition studying of liquid fuel is of feasibility. Autoignition delay time and autoignition height from the nozzle increase with the coflow temperature decreasing and autoignition delay time changes sensitively under lower coflow temperature. Liftoff height of diesel spray flame decreases with the increasing of coflow temperature. Lower temperature causes higher variance of liftoff height. It might be speculated that there are two different mechanisms of flame stabilization that the lower lift-off heights flames are related to a balance between the flow velocity and flame speed while the higher lift-off heights flames are stabilized by the mixture autoignition.

The objective of this work was to investigate the potential of the electrostatic atomization for its application in internal combustion engines. In this paper, a theoretical model for secondary breakup of charged droplets was established. The electric force reduces the surface tension of liquid, whereby atomization is promoted. To improve the diesel droplet atomization remarkably by means of electrostatic charge, the charge-mass ratio should be at least at the order of 10-6C/g. In the interest of the practical application conditions in internal combustion engines, the high-pressure injected electrospray was generated and investigated under various injection pressures and electric conditions. By means of the Photron high-speed camera, the special features of electrospray were observed. The micro-characters including the drop size distribution and the variance of the drop diameter in the spray front area were investigated.