The Diesel Engine Combustion System Control Strategy Research Based On Hybrid EGR To Meet China Stage V Emission Standards

Diesel engines have a distinct advantage over other internal combustion enginesin terms of reducing fuel consumption rate and CO2emissions because of its higherthermal efficiency. Therefore, it is widely used as a common power plant. In recentyears the growing energy crisis and environmental issues force emissions regulationsto be more stringent, EGR as an important technical to meet more stringent emissionsregulations. So in order to meet the China Stage V Emission Standards, this articlecarrys out the experiment about EGR technology and fuel injection control strategy.We carry out the experimental study on a diesel engine with two stageturbocharging system. Firstly, we carry out experimental study about the influence ofdifferent EGR ways on diesel engines performance and emissions. Study resultsindicate that at low speed conditions, LP-EGR way can gain higher intake, get verylow emissions about NOx and soot. At High speed conditions, when at high EGR rate,by introducing low pressure EGR, Hybrid EGR can increase the amount of intake andreduce and optimize pumping losses and improve the combustion process. HybridEGR can keep well fuel economy within the broad range of EGR, as well as improvethe trade-off relationship between Nox-soot.On the basis of optimization of EGR programme, we conducted ExperimentalStudy on fuel injection control strategy. Study results indicate that at the low speedconditions, the emission of all operation conditions could be controlled under theChina Stage V Emission Regulations by main injection parameters. Especially at thesmall load conditions, NOx could be controlled about0.5g/kW.h, and soot is under theChina Stage V emission regulations. At the high speed conditions, the emission ofNOx in all operation conditions could be controlled under2.0g/kW.h by maininjection parameters, increasing the pressure of injection and post injection, thespecific emission of soot could still under the emission regulations.The ESC cycle test showed that NOx and soot emission are all under the limitvalue of the China Stage V emission regulations, BSFC can be reach213g/kW.h. TheExperimental Study lay foundation for meets China Stage V Emission Standards.