Improving Performance For GW4G15Gasoline Engine

With the rapid development of world economy, the amount of automobileincreasing year by year, the resulting shortage of global oil resources and worseningenvironmental pollution, so people have a higher request for the performance of theinvestigated automobile engine. The paper takes the GW4Gl5Gasoline engine as theinvestigating subject. By comparing a lot of the engine performance which is at homeand abroad, the power and torque per displacement of GW4Gl5Gasoline engine are inlower level in similar displacement, and its performance has the potential to improve.Based on the analysis of the performance of engine related influencing factors, andcomparing with different pole prototype, we have formulated the GW4G15engineperformance optimization of the main technical scheme which the cam profile, exhaustmanifold and the cylinder assembly parts were optimized.First on the basis of the original engine, in the paper the experiments proved thatthe optimization of cam profile improved characteristics of GW4G15engine. Theresults show that gas flow loss decreases and volumetric efficiency increases after camprofile was optimized. Speed characteristics at WOT (Wide Open Throttle), powerperformance and fuel consumption are better than the original engine.On the basis of the optimization of cam profile, the experiments proved that theoptimization of exhaust manifold improved characteristics of GW4G15engine. Theresults show that exhaust system resistance decreases, residual gas coefficient decreases,air intake flow increases and volumetric efficiency increases after exhaust manifold wasoptimized. Speed characteristics at WOT, power performance and fuel consumption arebetter than the original engine.On the basis of the optimization of cam profile and exhaust manifold, mechanicalfriction loss, blow-by, lubricant consumption and speed characteristics at WOT of theassembly parts were verified by experiments. The results show that mechanical friction loss, blow-by, lubricant consumption reduce and in the middle and high speed periodpower performance and fuel consumption remarkably improve after the cylinderassembly parts of GW4G15gasoline engine were optimized.By optimizing the cam profile, exhaust manifold and the cylinder assembly parts,the optimized engine was obtained. The experiments proved that the optimized engineimproved characteristics of GW4G15engine. The experiments compared combustionperformance under the maximum power and torque condition. The results show that themost explosive pressure of engine increases, the moment of the most explosive pressurehappens in advance. The maximum pressure rise rate increases slightly. The moment ofcombustion start is advanced, combustion duration is shortened. At the same time, thatintake and exhaust performance could be further improved. Speed characteristics atWOT, power performance and fuel consumption are better than the original engine.By succeeding in optimizing the GW4G15gasoline engine, the result may providea good thought for the design of the new engine, at the same time can provide forreference for Great Wall series engine performance optimized.