The Research Of Quasi-dimensional Model For Spark-ignited Liquefied Petroleum Gas Engine

The roar developments of the modern industry not only give people many material benefits but also bring a series of social difficulties, such as environmental pollution and energy crisis that are taken into great consideration by all over the world people. Automobiles consume about half of the petrol of the world and at the same time they have been polluting our atmosphere seriously. At present, for auto engineers, the most important job is to design and develop more clean substitute fuel engines. We will solve the problems of environmental pollution and energy crisis strategically by using these engines.The computer Simulation has developed gradually along with the development of the computer .The rapid progress of the computer software and hardware not only provide the computer simulation research powerful technological support ,but also accelerated the development of the computer simulation further . As a result, a good many models come into being .Among them, the Quasi-dimensional model becomes popular because its practicability and low cost.In this paper, the emphasis is laid on the spark-ignited engine. A computer model for in-cylinder working process of spark-ignited engine is developed via using quasi-dimensional model. The model consists of a thermodynamic model, a heat transfer sub model ,a chemical equilibrium model and a two-zone combustion model.The model is anticipated to accurately predict performance of a LPG engine. Based on the model ,a relevant program is written by VB. In order to test the program, we did some experiments on a 4105LPG engine of Chaoyang Diesel Factory. The calculated results is relatively consistent with the experimental results. In the paper ,the changing pressure of 4105LPG engine during the cylinder-closed phase(with the exception of exchanging gas phase) under different rotate speed and different spark-ignited advanced angle conditions is calculated. The total produce of NO emission is also did. In addition, influence of different parameters to the performance of the engine analyzed, and the reason is pointed .In final, the characteristic of 4105LPG engine and that of original engine is compared. Based on the comparison, the feasibility of a diesel engine retrofitted to LPG engine is studied. The study results show that it is feasible to retrofit a diesel engine retrofitted to LPG engine.