| With the rapid development of industry and agriculture,the non-road mobile devices are widely used in various fields and the off-road diesel engine is the main power supplying mobile mechanical equipment which has been widely applied in our country.The popularization of mobile machinery provide a great positive effect on the development of society,but the pollutant emissions and energy consumption of diesel engine have attracted more and more people's attention,and lots of countries have established strict off-road diesel engine emission laws and regulations.In order to make the off-road diesel engine's emission meet GB20891-2014 Tier3 standards,the experiment study of reducing emission on the engine by eight mode test has been put in this paper.Firstly,the original diesel engine emissions performance has been tested,and the NOX+HC not meet the regulations limit by comparing with the emission regulations.Measures of reducing diesel engine emission by using turbocharger,electronically controlled unit pump and exhaust gas recirculation(EGR)technology has been formulated according to the experiment analysis.Secondly,the turbo surface diameter ratio of supercharge impacted on diesel engine's emissions and performance has been studied by using tree different surface diameter ratio.The 101 type supercharger(turbo surface diameter ratio is 52/78)is the best choice which is the most conducive to reduce emissions in does not affect the efficiency and performance according to the analysis of test results.Matching test research of type 101 and 102 supercharger with the diesel engine has been done,and the best choice of 101 type supercharger was demonstrated.Thirdly,the impact of the injection advance angle on diesel engine's emission and performance has been studied.According to the characteristics of setting different fuel injection advance angle in each operating mode in the electronically controlled unit pump,the best fuel injection advance angle of each mode was determined by analysis of test results,and the best advance angle of eight modes were-4oCA,-1oCA,-6oCA,0oCA,-10 oCA,-9oCA,-8oCA,and 0oCA respectively.The optimized NOX+HC reduced 32.2%,CO rose 7.7,and PM changed little was obtained by the eight-mode's discharge value calculation method.Additionally,the type of integrity streaming EGR was used by the analysis of EGR's decorated form.Using 101 type supercharger and the best fuel injection advance angle each mode,the impact of the EGR rate on diesel engine's emission and performance has been studied.the best EGR rate of each mode was determined by analysis of test results,and the best EGR rate of eight modes were10%,10%,20%,0,40%,20%,50%,and 2%respectively.The optimized NOX+HC reduced 32.2%,CO rose 7.7,and PM changed little was obtained by the eight-mode's discharge value calculation method.The optimizedemission values meet emission regulations and laws.The target of the test diesel's emission meeting GB20891-2014 Tier3 standards has been achieved in does not affect the fuel efficiency and performance by above best scheme. |
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