Study On The Feul Saving Potential For Applying Cooled EGR On Turbocharged Gasoline Engine

In order to control the automobile oil demand,reduce the greenhouse gas emissions,and realize the sustainable development of the automobile industry,all the developed countries and regions have published the automobile fuel economy regulations.In 2016,China’s passenger car production and sales reached 28 million,being the first of the world for consecutive 8 years.Till the end of 2016,China’s car ownership is 194 million.Undoubtedly,China is already a big auto country.Correspondingly,China fuel economy regulations are also consistent with the developed countries and regions.China stage-four passenger car fuel consumption standards was formally implemented on January 1,2016.From the overall trend,China stage-four passenger car fuel consumption standards,American CAFE standard,European carbon dioxide emissions standard,and Japanese weight-based passenger car economy standard,are consistent with the trend to tighten passenger car fuel economy.From 2015 to 2020,after conversion,the improvement rates are ranged between 3%-6%.Finally in 2020,the average passenger car fuel consumption will be reduced to about 5L/100 km.About how to achieve 2020 average passenger car fuel consumption standard,according to foreign and domestic research institutions,mainly relying on improvement of gasoline engine efficiency,the applying of cooled exhaust gas recirculation on turbocharged gasoline engine is considered as a potentially effective strategy.About how to improve turbocharged gasoline engine efficiency,this paper theoretically analyzed the limiting factors for turbocharged gasoline engine efficiency promotion: pumping loss,knock and exhaust temperature protection enrichment.Applying cooled exhaust gas recirculation system can effectively improve the energy losses in these three aspects.In automotive industry,before starting the expensive experiment study,it is common to use simulation study to obtain the preliminary conclusions.In this paper,with AMEsim software,the model of a 1.5L turbocharged gasoline engine with cooled exhaust gas recirculation system was built.After validation of the model,the effect of EGR rate on engine combustion was investigated.Through the optimization of control parameters,the fuel saving potential of this strategy was verified.Under the typical conditions of engine speed 2000r/min BMEP 9.0bar,with 5% EGR rate,the fuel consumption was reduced by 2.55%.In order to obtain the real fuel saving potential for applying cooled exhaust gas recirculation system on a 1.5L turbocharged gasoline engine,a comprehensive experimental study was conducted in this paper.On engine test bench,the cooled exhaust gas recirculation system was mounted on a 1.5L turbocharged gasoline engine,and the test platform was set up.Tests of the NEDC cycle 48 operating points were implemented,the results indicated that,applying cooled exhaust gas recirculation system,together with the optimization of engine control parameters,the NEDC synthesized calculation fuel consumption was reduced by 6.21%.The overall operation range engine calibration was carried out with DOE method,further calibration optimization was carried out on the vehicle.The results showed that,in the actual NEDC cycles,the fuel consumption was reduced by 6.03%;in the actual driving conditions,the average fuel consumption was reduced by 5.76%.