Study On Emission Characteristics Of Diesel Engine For Construction Machinery

Construction machinery diesel engine is widely used in the infrastructure construction,and its quantity has been growing rapidly for present.However,the environmental problem caused by emission of the diesel engine can not be ignored,due to poor working conditions,heavy load and frequently using of construction machinery diesel engine.Using experiment to study emission characteristics of the diesel engine will cost a lot of resources.While combined experiment with computer numerical simulation,it will be more efficient to reveal how related factors affect emission characteristics of the diesel engine.Therefore,the above method has been adopted in this paper to research emission characteristics of the target engine.Major work summarized as follows:(1)Taking the diesel engine assembled on Lingong Z50-LG953N loading machine as research object,this paper has carried out a bench test and real vehicle emission test on the target engine.Based on both test,this paper has worked out distribution of different conditions and emission under loading machine's normal operation and road operation,by recording the engine operating condition and emission data during actual test process.The result shows that,the engine has centralized operation phenomenon in both normal operation and road operation.(2)The working progress simulation model was built based on GT-Power.The model has adopted the droplet evaporation combustion model which was based on the quasi dimensional combustion model,which is able to calculate not only thermodynamic parameters and performance parameters,but also NO_x and Soot emission of diesel engine.(3)The simulation model was calibrated according to measured data.Then emission characteristics of the engine was analyzed based on the calibrated model.It has been revealed that the influences of injection pressure,main injection quantity,main injection angle,pre injection quantity and the interval angle between main injection and pre injection on emission of the diesel engine.(4)The coupling simulation model on economic and emission were built under modeFRONTIER and GT-Power.And it has explored the conditions which can reach the best performance of each mode.Results of the emission mode shows that NO_x emission can be reduced 8.83%by adjusting injection parameters at the expense of economic.Results of the economic mode shows that the BSFC can be reduced in a certain degree,along with dropping of Soot emission and increasing of NO_x emission.Therefore,which mode to choose depends on demands.