Browse Publications Technical Papers 2010-01-1124
2010-04-12

Effect of Variable Valve Timing on Diesel Combustion Characteristics 2010-01-1124

This paper investigates the effects of variable valve actuation on combustion in a Diesel engine. Early inlet valve closing (EIVC) lowered the pressure and temperature during the compression stroke, resulting in a longer ignition delay as the fuel mixed more homogenously with the charge air ahead of combustion. Combustion was characterized by prominent cool flame chemistry and a faster, more energetic, premixed combustion. Tests were performed on a 6.4L V8 engine at loads up to 5 bar BMEP. The use of EIVC showed significant reductions of soot (above 90%) and fuel efficiency improvements (of 5%) with NOx levels below the US 2010 standard of 0.2g/bhp-hr. The improvements in emissions and fuel economy came from controlling in-cylinder temperatures and optimizing combustion phasing. For a constant engine-out NOx emission, EIVC improved fuel economy as the amount of EGR and the engine back pressure requirement were reduced.

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

Analysis of the Impact on Diesel Engine Fuel Economy and Emissions by Variable Compression Ratio Using GT-Power Simulation

2010-01-1113

View Details

TECHNICAL PAPER

Technology for Improving Engine Performance using Variable Mechanisms

2007-01-1290

View Details

TECHNICAL PAPER

BSFC Investigation Using Variable Valve Timing in a Heavy Duty Diesel Engine

2009-01-1525

View Details

X