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Experimental Investigations of Intake and Exhaust Valve Timing Effects on Charge Dilution by Residuals, Fuel Consumption and Emissions at Part Load
ISSN: 0148-7191, e-ISSN: 2688-3627
Published April 16, 2007 by SAE International in United States
Annotation ability available
Experimental investigations of intake and exhaust valve timing effects at part load have been carried out on a 4 cylinder, 1.6 l spark ignition engine. The effects of valve timing on charge dilution by residual gases, and on fuel consumption and emission characteristics, have been explored. The valve timings, and particularly the duration of the valve overlap period, strongly influence levels of charge dilution. The extent to which this accounts for the observed changes in specific fuel consumption and emissions with valve timings is investigated. Residuals gas fraction values have been determined at various steady operating conditions through the analysis of gas samples drawn from the cylinder near the tip of the spark plug. A gasoline direct injection fuel injector operating in reverse flow was used as a high-speed sampling valve. Brake specific values reflect a combination of changes in dilution and, at different brake loads, changes in pumping work. The patterns of performance mapped out as functions of valve timing are illustrated and explained.
CitationShayler, P. and Alger, L., "Experimental Investigations of Intake and Exhaust Valve Timing Effects on Charge Dilution by Residuals, Fuel Consumption and Emissions at Part Load," SAE Technical Paper 2007-01-0478, 2007, https://doi.org/10.4271/2007-01-0478.
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