PDI Engine Low Pressure Fuel System Design And Optimization

Both of the PFI technical engine and GDI technical engine have their issues that difficult to fix to get better performance.The GDI engine can not get better mixture of air and fuel in low speed and low load status.Since the throttle in the air intake system,PFI engine can not get more air to achieve more better power in the all load status.PDI engine(GDI+PFI)can optimize them both,for higher requirements in the future.Basic on the key system fuel supply system requirements,design two different system model and related optimize method.For the further choice decision,research and confirm different performance of different approach by CAE(Computer Aided Engineering)、engine dyno test 、vehicle NVH test and vehicle fuel consumption test.Etc.First,set up two different approach model to simulate and optimize by the CAE after system research and build.Though the CAE we optimize different fuel pipe material、different damper group design and different position of the damper to get the best approach for the pressure wave.The third,build the system and test on the engine dyno and in the vehicle.The results and conclusions are as follows:(1)Constant fuel supply system pressure wave condition is similar like variable fuel supply system without closed control but worse than closed control variable system,all of them can fulfill engine requirement with good calibration;Constant fuel supply system have worse NVH performance,need optimize by silence cover.etc.These optimize method will cause cost increase.(2)Variable fuel supply system have similar fuel consumption performance as constant fuel supply system,but have very good energy consumption performance,it will be better for the whole vehicle electric balance.The constant system may have better fuel consumption performance together with smart generator.(3)Constant fuel supply system have low cost,variable fuel supply system are more expensive,but it will be the future since more and more critical regulation requirements and customer comfortable requirements.