CFD investigation of fluid flow and turbulence field characteristics in a four-stroke automotive direct injection engine

摘要

The CFD simulation to investigate the effect of piston crown inside the combustion chamber of a 4-stroke direct injection automotive engine under the motoring condition is presented. The analyses are dedicated to investigate the outcome of the piston shape differences to the fluid flow and turbulence characteristics for air-fuel mixture preparation in the terms of swirl and tumble ratio, turbulence kinetic energy, turbulence dissipation rate and turbulence viscosity along the degree of crank angle occurred inside this engine. The numerical calculations were performed in a single cylinder of 1.6 litre of a 4-stroke direct injection engine running at wide open throttle condition by using the CFD code to obtain the better piston crown used for such engine. Two different piston bowls for certain engine speeds were considered to be compared to evaluate those mentioned parameters produced during intake and compression stroke. The results obtained from the numerical analysis can be employed to examine the homogeneity of air-fuel mixture configuration for better combustion process and engine performance.