1975-02-01

The Effects of Charge Dilution on Combustion and Its Improvement-Flame Photograph Study 750054

The adverse effects of charge dilution on combustion of spark ignition engines are well known; as a tool for reduction of nitrogen oxide emission, it becomes important.
Some methods of analyzing combustion phenomena in a single-cylinder engine (27.1 CID) with charge dilution were tried. Multiple ionization probes roughly indicate the pattern of flame propagation, but details of the flame, especially charge dilution, cannot be measured by this method. Flame photographs, on the other hand, showed clearly the effects of combustion chamber design on flame propagation and its cyclic dispersion. The effects of combustion chamber configuration, ignition energy and spark duration, ignition timing, composition of diluent gas, air-fuel ratio, and mixture homogeneity were examined. Mass burnt fraction was calculated from both flame photographs and pressure indicator diagrams.
A combustion chamber having high turbulence and a rich air-fuel ratio promoted the initial flame propagation and flame speed and improved cyclic dispersion.
For high turbulence design, the combustion chamber of the commercial 97.5 CID, 4-cyl engine was modified. Fluctuation of output torque was measured and analyzed by correlation and probability analyses. This analysis indicated that high turbulence design was effective for improvement of car surge caused by EGR, and this was confirmed by actual driving on the road.

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

Control of the Start of HCCI Combustion by Pulsed Flame Jet

2002-01-2867

View Details

TECHNICAL PAPER

Effects of Hydrogen Enhancement on Efficiency and NOx Emissions of Lean and EGR-Diluted Mixtures in a SI Engine

2005-01-0253

View Details

TECHNICAL PAPER

Lean-Burn Fuel Development Using the Correlation of CVCC and Engine Test

961158

View Details

X