Performance and Emission Characteristics of HD Diesel Using EGR Under Low-Speed and High-Load Conditions
The effects of air boost system,inlet temperature,EGR and fuel injection control strategy on the performance and emissions were studied in a common-rail heavy-duty (HD)diesel engine under low speed and high load conditions.Results show that,EGR recyclability is enhanced,and the trade-offs of NOx-BSFC and NOx-soot are improved effectively via reducing turbine and compressor flow reasonably of single-stage turbocharging system or using two-stage turbocharging (2 TC) system.With the increase of inlet temperature,the increase of EGR rate and the reduction of NOx are restricted because of excessive high exhaust temperature.Thus,the trade-offs of NOx-BSFC and NOx-soot are improved when inlet temperature is reduced.Compared with HP-EGR,LP-EGR can effectively enhance EGR recyclability and working capability of turbocharging system,and improve the trade-offs of NOx-BSFC and NOx-soot and decrease NOx to a lower level.For the same NOx emissions,soot is reduced dramatically by lowering injection pressure and postponing injection timing.Moreover,soot and BSFC are reduced further by employing main-post injection strategy with optimized interval angle between main injection and post injection,as well as optimized fuel quantity of post injection.
heavy-duty diesel enginelow speedhigh loadexhaust gas recirculationperformanceemissions
NETL
NSTL
万方数据
维普
