The Performance Simulation And Optimization Of Cng Engine For Large Bore

In modern society,With the continued development of national economy and the adjust of the pattern of energy, which make the demand of high power gas engine increasing. Expecially the high power gas engine which has more predominant market. In the situation of imbalance between supply and demand for petroleum, seeking the clean energy becomes the important element of develop.The natural gas becomes an alternative fuel with great potential for development,for its low emission,cheap price and abundant resource. The high power gas engines are reequipped from diesel engine. For the requipped engine, The biggest problem is the decrease of power.For studing the reason of the decrease of power for requipped gas engine and how to recover. This paper takes an example for certain large bore diesel engine. And the research is made on large bore diesel engine natural gas engine originated from it.The main research work includes:(1)The large bore diesel engine model is built up with GT-Power and the performance is simulated. The computing result is contrasted with the test result.(2)A natural gas engine mode is built on the basis of the diesel engine model:getting rid of the inject system; adding the spark system and supply system of natural gas; adding prechamber;which make the diesel engine become the spark plug natural gas engine with prechamber.And according to the combustion mode,the diesel engine is requipped to equivalent pattern and dispersion pattern.(3)Forecasting the performance of the requipped CNG engine and contrasting the result with diesel engine.(4) Aalysing optimism measure for simulated CNG engine.Through the simulation Of diesel process,the results and the experimental results were compared,the error all with in 5% and output graphics and similar type diesel engine practical work process change trend is consistent illustrates the accuracy of model.Modified equivalent type of pre-combustion gas and poor quantity type of gas engine pre-combustion simulated results and original diesel engine simulation results were found,dynamic contrast is decreased,cylinder economy temperature and dynamic,but the biggest problem is the decline,and poor performance of quantity type is slightly better than equivalent type of modification,burning more fully,power is about the original diesel combustion performance is good,78 percent,so favors for pre-combusion gas engine combustion.Through analyzing the reasons of natural gas engines,performance,and puts forward the compression ratio,advanced ignition angle with gas phase of air-fuel and the main influence factors of these parameters optimization,analysis the influence of engine power,and puts forward the relevant advice.