Influence of Pilot Injection on Combustion Characteristics and Emissions in a DI Diesel Engine Fueled with Diesel and DME Ulsan Univ

Format:

Conference/Event

Author/Creator:

Jung, Jung, author.

Contributor:

Iida, Norimasa

Jeong, Jae Hoon

Lee, Young-Jae

Lim, Ock Taeck

Pyo, Young Duck

Conference Name:

SAE International Powertrains, Fuels and Lubricants Meeting (2011-08-30 : Kyoto, Japan)

Language:

English

Physical Description:

1 online resource

Place of Publication:

Warrendale, PA SAE International 2011

Summary:

This work experimentally investigates how the dwell time betweenpilot injection and main injection influences combustioncharacteristics and emissions (NOx, CO, THC and Smoke) in asingle-cylinder DI diesel engine. Additionally, results from dieselinjection are compared with those shown in dimethyl ether (DME)injection under the identical injection strategy to demonstrate thesensitivity of the combustion characteristics and emissions tochanges of the fuel type. Two fuel injection systems are appliedfor this experiment due to the differences of fuel characteristicwith regard to physical and chemical properties. The injectionstrategy is accomplished by varying the dwell time (10°CA, 16°CAand 22°CA) between injections at five main injection timings (-4°CAaTDC, -2°CA aTDC, TDC, 2°CA aTDC and 4°CA aTDC).It was found that pilot injection offers good potential to lowerthe heat-release rate with reduced pressure traces regardless ofthe dwell time between injections and fuel type. Pilot injectionalso allows stable combustion even for extensive combustion phasingretard, which reduces the NOx emissions. This means that it isindeed possible, and higher BMEP could be achieved for pilot-maininjection operation. Contrary to the expectations, pilot injectionis found to play a lesser role in reducing the NOx emissions, butNOx formation is mainly suppressed by the combustion phasing retardeffect. A comparison of the emissions between diesel injection andDME injection under identical injection strategy shows that evenDME injection exhibits higher NOx emissions than diesel injection,pilot injection is found to be more effective on DME for reducingthe amount of NOx with combustion phasing retard, which indicates alevel of NOx emissions similar to that of diesel injection. The COand THC emission levels vary significantly with injectionstrategies in diesel injection, but they are typically found to belower than 100 ppm in DME injections. Although the dieselpilot-main injection conditions show higher PM emissions thansingle-injection condition, DME has little PM regardless ofinjection strategy

Notes:

Vendor supplied data

Publisher Number:

2011-01-1958

Access Restriction:

Restricted for use by site license