| With the rapid development of the domestic auto market, cars possession quantity in China has continue increased, and environment and energy`s pressure which comes from the internal combustion engine become more and more huge. In China, gasoline powered motor vehicles account to more than 70% share. Developing and applying new energy-saving technology on gasoline engine has great significance. This paper intends to development a type of 1.8L gasoline from the existing 2.4L gasoline engine platform, focusing on the optimization design of the combustion system.Firstly, Thermal dynamic calculation model had been built to predict the engine performance between different compression ratio and intake valve seat diameters. Considering the structure and performance, compression ratio increase to 10.5 and intake valve seat diameter increase 1.6mm.Meamwhile, the corresponding piston model and six kinds of intake port models had been designedIn order to study the flow characteristic of all the intake port cases, steady simulation model was established, and the change of no-dimensional discharge coefficient, turbulence ratio were investigated. After contrasting the results, three cases were selected for further research.Then, transient simulation model was established to study the in-cylinder flow structure and analysis on indicator diagram, cylinder temperature, total mass, turbulent kinetic energy, throttle flow velocity was also carried out. The final results shows model 3 has obvious advantages.According to the simulation result, 1.8L engine which adopted model 3 has been trial-produced, and experimental date was get on the texting block. Dynamometer data shows that the power reaching 95.28kW at 6000rpm and the maximum torque reaching 179.86N.m at 4000rpm. Vehicle actual road conditions emission test data show that at all the conditions the emission is lower than EUⅣstandard. Overall, all index of the engine has achieved or close to develop target. |
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