Exploring the Charge Composition of SI Engine Lean Limits

2009-01-0929

04/20/2009

Event
SAE World Congress & Exhibition
Authors Abstract
Content
In this paper the experimental performance of the lean limits is examined for two different types of engines the first a dedicated LPG high compression ratio 2-valve per cylinder engine (Ford of Australia MY 2001 AU Falcon) and the second a gasoline moderate compression 4-valve per cylinder variant of the same engine (Ford of Australia MY 2006 BF Falcon). The in-cylinder composition at the lean limit over a range of steady state operating conditions is estimated using a quasi-dimensional model. This makes it possible to take into account the effects of both residual fraction and fresh charge diluents (EGR and excess air) that allow the exploration of a modeled lean limit performance [1, 2]. The results are compared to the predictions from a model for combustion variability applied to the quasi-dimensional model operating in optimization mode. The conclusion of the analysis is an unexpected finding that the engine tolerance to the total diluents remains almost constant throughout its operation domain. Although some differences exist between the residual fraction and the incoming charge diluents in terms of energy content, the results of this study suggest that their effect on the lean limit operation is almost the same.
Meta TagsDetails
DOI
https://doi.org/10.4271/2009-01-0929
Pages
9
Citation
Mehrani, P., Watson, H., and Dingli, R., "Exploring the Charge Composition of SI Engine Lean Limits," SAE Technical Paper 2009-01-0929, 2009, https://doi.org/10.4271/2009-01-0929.
Additional Details
Publisher
Published
Apr 20, 2009
Product Code
2009-01-0929
Content Type
Technical Paper
Language
English