Study On Matching Of Fuel Injection Method And Combustion Chamber Of A Gasoline Direct Injection Engine

In recent years,gasoline direct injection engines are the product development and application hot spots of domestic and foreign automobile companies.because the fuel is sprayed inside the cylinder,the vaporization process of the gasoline absorb a large amount of heat in the combustion chamber,and this can reduces the temperature of the air-fuel mixture and the wall temperature of the combustion chamber,so that the temperature of the mixture at the end of the compression stroke is significantly reduced.Therefore,the anti-knock capability is strengthened,so the engine can use a higher compression ratio,and increase the spark plug ignition advance angle,enhance the engine power and economy.Compared with the same performance PFI engines,GDI homogeneous combustion engines can improve the fuel economy of 2-4%,while the application of turbocharge and downsizing technology,the turbocharged GDI engines can improve 10-15% of the fuel economy,at the same time engine power and emissions are also greatly improved.This paper combines a product research development project of the company,study on the combustion related parts of a gasoline direct injection engine.Based on the preliminary simulation analysis results and combustion development testing result,choose the best matching solution of injector injection mode and piston combustion chamber which will meet the project performance targets.This paper applies 1D-thermodynamic calculation software and 3D-fluid analysis software to simulate the combustion system,combination with engine air path,cylinder head combustion chamber and cylinder bore,piston,and these will be a composition of dynamic grid.According to the configuration of the injector parameters,the CFD model is built.Finally,the simulation analysis of air intake,compression,and combustion process is carried out by Star-CD software.After the evaluation of simulation results,the basic parameters of combustion system can be determined,the prototype parts of cylinder head,piston,and different solution injectors will be machined using rapid prototyping method.A prototype engine then will be assembled for testing.Finally,the engine performance including power,torque and emission will be evaluated on test rig with different matching solution,and the final solution which meet the project targets will be confirmed for the engine industrialization development.