Title: A comparison between cylinder charge composition of common rail diesel engine

Authors: P. Eastwood, K. Tufail, T. Winstanley, A. Darlington, S. Karagiorgis, Y. Hardalupas, A.M.K.P.Taylor

Addresses: Diesel Powertrain Development and Integration Group, Ford Motor Company, Dunton, Essex SS15 6EE, UK. ' Diesel Powertrain Development and Integration Group, Ford Motor Company, Dunton, Essex SS15 6EE, UK. ' Diesel Powertrain Development and Integration Group, Ford Motor Company, Dunton, Essex SS15 6EE, UK. ' AVL Powertrain UK Ltd, Essex SS15 6TW, UK. ' AVL Powertrain UK Ltd, Essex SS15 6TW, UK. ' Mechanical Engineering Department, Imperial College London, London SW7 2BX, UK. ' Mechanical Engineering Department, Imperial College London, London SW7 2BX, UK

Abstract: Using a diesel passenger-car, we measured charge composition and emissions of nitrogen oxide and soot, on the European extra-urban drive cycle (EUDC), and also on isolated transients, representative of the EUDC. Our objective was to compare emissions and charge composition, between a transient, and engine operation at specific points on the transient locus (|quasi-steadystate|). On the EUDC, we measured two nitrogen oxide spikes. The first, fast-response nitrogen oxide spike, could be ascribed to the pedal demand step input: this is small, compared to the second nitrogen oxide spike resulting from the remainder of the transient (adjustments in speed and load). The estimated charge composition, in a transient, agreed closely with the measurement, both qualitatively and quantitatively. The burned-gas fraction (BGF), estimated from a transient, revealed that the period of largest discrepancy from that demanded, is short (≈1 sec). This indicates that the use of BGF, rather than the customary mass air-flow, may be more apposite during transients encountered in real driving. However, since this discrepancy is short-lived, the realisable reduction in overall NOx emissions, using BGF as a controlled variable, at least during the EUDC, is likely to be small. BGF-based control is nevertheless attractive, insofar as boundary conditions bearing direct relationships to combustion are easily imposed.

Keywords: BGF; burned gas fraction; charge composition; rail diesel engines; estimated; EGR; exhaust gas recirculation; transients; nitrogen oxide emissions; soot emissions; European extra-urban drive cycle; EUDC; railways.

DOI: 10.1504/IJVD.2009.024245

International Journal of Vehicle Design, 2009 Vol.49 No.1/2/3, pp.150 - 167

Available online: 30 Mar 2009 *

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