This content is not included in your SAE MOBILUS subscription, or you are not logged in.
Comparison of Dual Retard VCT to Continuously Variable Event Valvetrain
ISSN: 0148-7191, e-ISSN: 2688-3627
Published March 08, 2004 by SAE International in United States
Annotation ability available
Variable cam timing strategies which utilize retard of the intake and exhaust valve events at part load have been previously shown to provide improved fuel consumption and feedgas NOx. These benefits can be increased by enhancing the combustion system with variable charge motion.
A variable event duration valvetrain was simulated on engine dynamometer by running a series of short duration/low lift intake valve events. The fuel consumption benefit for this simulated variable event valvetrain is compared to that of dual retard VCT with variable charge motion.
An estimated upper limit for the fuel consumption improvement potential of variable valve timing is presented. This upper limit includes both pumping work reduction and indicated efficiency improvement with high levels of exhaust residual dilution. The measured benefits of dual retard VCT and of the variable event valvetrain are compared to the estimated upper limit.
CitationJung, H., Stein, R., and Leone, T., "Comparison of Dual Retard VCT to Continuously Variable Event Valvetrain," SAE Technical Paper 2004-01-1268, 2004, https://doi.org/10.4271/2004-01-1268.
- Stein, R. A. Galietti, K. M. Leone, T. G. “Dual Equal VCT - A Variable Camshaft Timing Strategy for Improved Fuel Economy and Emissions” SAE paper 950975 1995
- Leone, T. G. Christenson, E. J. Stein, R. A. “Comparison of Variable Camshaft Timing Strategies at Part Load” SAE paper 960584 1996
- Stein, R. A. Chou, T. Lyjak, J. C. “The Combustion System of the Ford 5.4L 3-Valve Engine” Global Powertrain Congress 2003
- Flierl, R. Kluting, M. “The Third Generation of Valvetrains for Throttle-Free Load Control” SAE paper 2000-01-1227 2000
- Sellnau, M. Rask, E. “Two-Step Variable Valve Actuation for Fuel Economy, Emissions, and Performance” SAE paper 2003-01-0029 2003
- Shelby, M. H. Stein, R. A. Warren, C. C. “A New Analysis Method for the Proper Accounting of IC Engine Pumping Work and Indicated Work” SAE paper 2004-01-1262 2004
- Tuttle J. H. “Controlling Engine Load by Means of Late Intake-Valve Closing” SAE paper 800794 1980
- Tuttle J. H. “Controlling Engine Load by Means of Early Intake-Valve Closing” SAE paper 820408 1982
- Hara S. Nakajima Y. Nagumo S. “Effects of Intake-Valve Closing Timing on Spark-Ignition Engine Combustion” SAE paper 850074 1985
- Nagumo S. Hara S. “Study of fuel economy improvement through control of intake valve closing timing: cause of combustion deterioration and improvement” JSAE Review 16 1995 13 19 1995
- Urata, Y. Umiyama, H. Shimizu, K. Fujiyoshi, Y. Sono, H. Fukuo, K. “A Study of Vehicle Equipped with Non-Throttling S.I. Engine with Early Intake Valve Closing Mechanism” SAE paper 930820 1993