Investigation of Diesel combustion using multiple injection strategies for idling after cold start of passenger-car engines

• Published in: Experimental thermal and fluid science Vol. 34; no. 7; pp. 857 - 865
• Main Authors: Payri, F., Broatch, A., Salavert, J.M., Martín, J.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 01-10-2010; Elsevier
• Subjects: ADVANCED PROPULSION SYSTEMS; Applied sciences; AUTOMOBILES; Centroids; Cold start; Cold starts; COMBUSTION; Combustion of liquid fuels; Combustion stability; Combustion. Flame; CORRELATIONS; CYLINDERS; Diesel; Diesel combustion; DIESEL ENGINES; DIRECT INJECTION ENGINES; Energy; Energy. Thermal use of fuels; Engines; Exact sciences and technology; HEAT; Idle operation; INJECTION; Multiple injection; OPERATION; STABILITY; START-UP; Strategy; TEMPERATURE RANGE 0065-0273 K; Theoretical studies. Data and constants. Metering; VARIATIONS; Idle operation; Combustion stability; Cold start; Diesel combustion; Multiple injection; Cold process; Stability; Diesel fuel; Diesel engine; Combustion; Experimental study; Idling; Starting; Strategy; Fuel injection; Direct injection
• ISSN: 0894-1777; 1879-2286
• DOI: 10.1016/j.expthermflusci.2010.01.014

A comprehensive investigation was carried out in order to better understand the combustion behaviour in a low compression ratio DI Diesel engine when multiple injection strategies are applied just after the engine cold starts in low temperature conditions (idling). More specifically, the aim of this study was twofold: on one hand, to understand the effect of the multiple injection strategies on the indicated mean effective pressure; on the other hand, to contribute to the understanding of combustion stability characterized by the coefficient of variation of indicated mean effective pressure. The first objective was fulfilled by analyzing the rate of heat release obtained by in-cylinder pressure diagnosis. The results showed that the timing of the pilot injection closest to the main injection was the most influential parameter based on the behaviour of the rate of heat release (regardless of the multiple injection strategy applied). For the second objective, the combustion stability was found to be correlated with the combustion centroid angle. The results showed a trend between them and the existence of a range of centroid angles where the combustion stability is strong enough. In addition, it was also evident that convenient split injection allows shifting the centroid to such a zone and improves combustion stability after start.