Browse Publications Technical Papers 2009-01-1354
2009-04-20

Effect of Multiple Injection Strategies on Emission and Combustion Characteristics in a Single Cylinder Direct-Injection Optical Engine 2009-01-1354

The effect of multiple injections in a heavy-duty diesel engine was investigated by focusing on single-pilot injection and double-pilot injection strategies with a wide injection timing range, various injection quantity ratios, and various dwell times. Combustion characteristics were studied through flame visualization and heat release analyses as well as emissions tests.
Single-pilot injection resulted in a dramatic reduction in nitrogen oxide and smoke emissions when the injection timing was advanced over 40° CA before the start of injection (BSOI) due to combustion with partially premixed charge compression ignition. A brown-colored flame area, which indicates a very fuel-rich mixture region, was rarely detected when more fuel was injected during single-pilot injection. However, hydrocarbon emission increased up to intolerable levels because fuel wetting on the cylinder wall increased. When double-pilot injection was applied, nitrogen oxide and smoke emissions were lowered by up to 73% and 84%, respectively, compared with single-injection. This result implies that double-pilot injection induced a better premixed mixture due to an improved turbulent effect between the two pilot injections. Furthermore, hydrocarbon emission was reduced by 50% compared with single-pilot injection because the spray tip penetration of double pilot injection was shortened, which resulted in a reduced amount of wall-wetted fuel. Images from the double-pilot injection experiment revealed that the diffusion burn portion was decreased and the luminosity intensity was the weakest among all the other experimental conditions.

SAE MOBILUS

Subscribers can view annotate, and download all of SAE's content. Learn More »

Access SAE MOBILUS »

Members save up to 18% off list price.
Login to see discount.
Special Offer: Download multiple Technical Papers each year? TechSelect is a cost-effective subscription option to select and download 12-100 full-text Technical Papers per year. Find more information here.
We also recommend:
TECHNICAL PAPER

Emissions Comparisons of an Insulated Turbocharged Multi-Cylinder Miller Cycle Diesel Engine

980888

View Details

TECHNICAL PAPER

Excess Emissions and Fuel Consumption of Modern Spark Ignition Passenger Cars at Low Ambient Temperatures

2012-01-1070

View Details

TECHNICAL PAPER

Development of Real-Time Engine Control Using the In-Cylinder Pressure Signal in a Diesel Engine for Passenger Vehicle

2013-01-2513

View Details

X