Study On Fuel-Air Mixture Forming And Combustion Process In Hydrogen/Diesel Engine Of Premixed Charge Compression Ignition

Nowadays the energy sources crisis and the environment problem becomes more and more strictness. As the traditional gasoline and diesel engine combustion mode can not depress the particulate matter (PM) and nitrogen oxides (NO_X) simultaneously. So it is necessary to investigate new combustion methods to solve these problems. Quasi homogeneous charge compression ignition (QHCCI) combustion may be with low emissions, especially for soot and NO_X, according as the most fuel which is pre-mixed is lean burnt. Also the QHCCI combustion may be with a better economical efficiency for a high burning speed. So it is the researching hotspot in the internal combustion engine filed, which is deemed to be the best promising combustion mode to replace the traditional mode.The fuel-air mixture forming and combustion process in hydrogen/diesel engine of premixed charge compression ignition is studied deeply in this paper. Firstly, the mathematic modes were built according to the characteristics of the hydrogen/diesel engine working progress. The KIVA-3V codes were rebuilt successfully to simulate the working process of both the hydrogen/diesel engine and the pure diesel engine. Secondly, the progress of the fuel-air mixture forming before combustion were studied in the hydrogen/diesel engine cylinder, and then the influence law to the fuel-air mixture forming of the diesel spray characteristics, the number of the inject hot, the initial swirl and the speed of the engine rotation were analysed. Lastly, the progress of the ignition and combustion of the hydrogen/diesel engine were studied, and also to analyse the influence to the progress of the ignition and combustion of the parameters above. The last step is to get the condition to actualize the QHCCI combustion.The following conclusions can be found from the analysis of the numerical simulation.Firstly, The KIVA-3V after being rebuilt can successfully simulate the working process of both the hydrogen/diesel engine and the pure diesel engine, according to the contrast of the result between simulation and experiment, it is the reliable base for the future research.Secondly, the laws of the fuel-air mixture forming and combustion process were gained about the hydrogen/diesel engine of premixed charge compression ignition. The whole combustion process is the same as the QHCCI combustion mode. First step, the diesel particulates are ignited due to the compression of the piston. Then the hydrogen around the diesel is ignited for the energy produced by the diesel combustion. At last, the most acutely premixed combustion of hydrogen is following. The combustion becomes more and more acutely with the increase of the hydrogen, and both NO_X and soot could be reduced by controlling the mass the hydrogen.The fuel-air mixture forming and combustion process in hydrogen/diesel engine of premixed charge compression ignition are badly affected by the diesel spray characteristics, the number of the inject hots, the initial swirl and the speed of the engine rotation. The laws about the influence were gained.The fuel-air mixture forming and combustion process could be controlled by selecting appropriate the number of the inject hots, the initial swirl, the speed of the engine rotation, the injection crank time, the injection velocity, the inject diesel mass and the hydrogen mass. In a word, the QHCCI combustion mode could be carried out by controlling parameters above properly of the hydrogen/diesel engine.