Article: Relevance of valve overlap for meeting Euro 5 soot emissions requirements during load transient process in heavy duty diesel engines Journal: International Journal of Vehicle Design (IJVD) 2006 Vol.41 No.1/2/3/4 pp.343 - 367 Abstract: This work describes the influence on performance and soot emissions of using different valve overlap camshafts during load transient processes in a heavy duty (HD) diesel engine equipped with a variable geometry turbine (VGT) in its turbocharger and a selective catalyst reactor (SCR) in the exhaust line. Based on the results of experiments and calculations, in this paper a description is given of how the valve timing affects the instantaneous exhaust and intake pressure, the short-circuit of the air mass flow, the prejudicial backflows, the performance of the turbine and hence the general performance and pollutant emissions of a VGT equipped HD diesel engine during a transient process. The paper concludes that very low or no overlap is imperative if a VGT is used to meet forthcoming pollutant emissions restrictions and to improve the transient response of HD turbocharged diesel engines. Inderscience Publishers - linking academia, business and industry through research

Title: Relevance of valve overlap for meeting Euro 5 soot emissions requirements during load transient process in heavy duty diesel engines

Authors: J. Galindo, J.R. Serrano, F. Vera, C. Cervello, M. Lejeune

Addresses: Universidad Politecnica de Valencia, CMT-Motores Termicos, Camino de Vera, s/n, 46022 Valencia, Spain. ' Universidad Politecnica de Valencia, CMT-Motores Termicos, Camino de Vera, s/n, 46022 Valencia, Spain. ' Universidad Politecnica de Valencia, CMT-Motores Termicos, Camino de Vera, s/n, 46022 Valencia, Spain. ' Universidad Politecnica de Valencia, CMT-Motores Termicos, Camino de Vera, s/n, 46022 Valencia, Spain. ' Volvo Powertrain France, Lyon, France

Abstract: This work describes the influence on performance and soot emissions of using different valve overlap camshafts during load transient processes in a heavy duty (HD) diesel engine equipped with a variable geometry turbine (VGT) in its turbocharger and a selective catalyst reactor (SCR) in the exhaust line. Based on the results of experiments and calculations, in this paper a description is given of how the valve timing affects the instantaneous exhaust and intake pressure, the short-circuit of the air mass flow, the prejudicial backflows, the performance of the turbine and hence the general performance and pollutant emissions of a VGT equipped HD diesel engine during a transient process. The paper concludes that very low or no overlap is imperative if a VGT is used to meet forthcoming pollutant emissions restrictions and to improve the transient response of HD turbocharged diesel engines.

Keywords: 1D gas dynamic modelling; heavy duty diesel engines; turbocharger lag; valve timing; vehicle emissions; valve overlap; soot emissions; load transient process; variable geometry turbine; VGT; selective catalyst reactor; SCR.

DOI: 10.1504/IJVD.2006.009675

International Journal of Vehicle Design, 2006 Vol.41 No.1/2/3/4, pp.343 - 367

Published online: 04 May 2006 *

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Title: Relevance of valve overlap for meeting Euro 5 soot emissions requirements during load transient process in heavy duty diesel engines

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