Using Multiple Injection Strategies in Diesel PCCI Combustion: Potential to Extend Engine Load, Improve Trade-off of Emissions and Efficiency Tianjin University

Format:

Conference/Event

Author/Creator:

Lu, Lu, author.

Contributor:

Su, Wanhua

Yu, Wenbin

Conference Name:

SAE 2011 World Congress & Exhibition (2011-04-12 : Detroit, Michigan, United States)

Language:

English

Physical Description:

1 online resource

Place of Publication:

Warrendale, PA SAE International 2011

Summary:

The Premixed Charge Compression Ignition (PCCI) engine has thepotential to reduce soot and NOx emissions whilemaintaining high thermal efficiency at part load conditions.However, several technical barriers must be overcome. Notably waysmust be found to control ignition timing, expand its limitedoperation range and limit the rate of heat release. In this paper,comparing with single fuel injection, the superiority ofmultiple-pulse fuel injection in extending engine load, improveemissions and thermal efficiency trade-off using high exhaust gasrecirculation (EGR) and boost in diesel PCCI combustion is studiedby engine experiments and simulation study.It was found that EGR can delay the start of hot temperaturereactions, reduce the reaction speed to avoid knock combustion inhigh load, is a very useful method to expand high load limit ofPCCI. EGR can reduce the NOx emission to a very smallvalue in PCCI. At low engine load using high EGR, low soot, CO, UHCand NOx emissions can be simultaneously achieved. Thereare no significant differences in mixture formation beforeignition, emissions and thermal efficiency using single andmulti-injection at low load. At low load, with the increase of EGRrate, smoke emission of PCCI doesn't increase obviously becausethe homogeneous mixture avoids fuel-rich. At higher engine loadwith high EGR, the localization of single injection in extendingoperation range is the high soot, CO and UHC emissions; usingmulti-injection mode, the CO and UHC emissions are decreased withlittle expense of NOx emissions. Comparing with singleinjection, multi-injection is more beneficial for lean andhomogenous mixture formation, especially at high load. With intakeboost using multi-injection, the engine load can be furtherextended; despite the ignition time is advanced, the leanness andhomogeneity of the mixture are improved; the indicated thermalefficiency is increased, and the CO and soot emissions are greatlydecreased with not large expense of NOx emissions. UsingPCCI with high EGR and boost, the IMEP of the engine can be furtherextended to 1.01 MPa, while keeping near to zero emissions and highthermal efficiency up to 47%

Notes:

Vendor supplied data

Publisher Number:

2011-01-1396

Access Restriction:

Restricted for use by site license