Operating Characteristics of DME-Gasoline Dual-fuel in a Compression Ignition Engine at the Low Load Condition Korea Advanced Inst. of Science and Tech

Format:

Conference/Event

Author/Creator:

Kim, Kim, author.

Contributor:

Bae, Choongsik

Conference Name:

Asia Pacific Automotive Engineering Conference (2013-04-01 : Bangkok, Thailand)

Language:

English

Physical Description:

1 online resource

Place of Publication:

Warrendale, PA SAE International 2013

Summary:

Combustion and emission characteristics were investigated in acompression ignition engine with dual-fuel strategy using dimethylether (DME) and gasoline. Experiments were performed at the lowload condition corresponding to indicated mean effective pressureof 0.45 MPa. DME was directly injected into the cylinder andgasoline was injected into the intake manifold during the intakestroke. The proportion of DME in the total input energy wasadjusted from 10% to 100%. DME DME injection timing was widelyvaried to investigate the effect of injection timing on thecombustion phase. Injection pressure of DME was varied from 20 MPato 60 MPa. Exhaust gas recirculation (EGR) was controlled from 0%to 60% to explore the effect of EGR on the combustion and emissioncharacteristics.As DME proportion was decreased with the increased portion ofgasoline, the combustion efficiency was decreased but thermalefficiency was increased. Injection timing was controlled to ensuremaximum thermal efficiency for all experimental conditions.Unburned hydrocarbon resulted from over-lean mixture and creviceregion was increased. Combustion was dominated by the premixedcombustion when the gasoline portion increased so the combustionduration was shortened. It affected the quasi-constant volumecombustion and the reduced heat transfer loss. Nitric oxides(NOx) emissions were decreased with increased gasolineproportion due to low combustion temperature from lean premixedcombustion even with decreased combustion duration. Soot emissionwas nearly zero regardless of DME proportion and injectiontiming.When the DME injection pressure increased, NOxemission was monotonically increased with improved thermalefficiency. Ignition delay was significantly decreased since thefuel atomization and mixing process were enhanced due to the highspray momentum. Combustion duration was also shortened with intenseheat release.With increased EGR rate, the thermal efficiency of dual-fuelcombustion was not decreased much but NOx emission wassignificantly reduced. This was attributed to the increased heatcapacity of the in-cylinder charge resulting in decreasedcombustion temperature.High thermal efficiency and low NOx emissions wererealized with the optimized fuel proportion, injection timing,injection pressure and EGR rate. Compared to only DME fuel concept(single fuel concept), lower fuel consumption and improved emissioncharacteristics were achieved with optimized gasolineproportion

Notes:

Vendor supplied data

Publisher Number:

2013-01-0049

Access Restriction:

Restricted for use by site license