In-cylinder studies of CAI combustion with negative valve overlap and simultaneous chemiluminescence analysis

Yang, Changho; Zhao, Hua; Megaritis, Thanos

Abstract

The negative valve overlap has been shown as one of the most effective means to achieve controlled autoignition combustion in a four-stroke gasoline engine. A number of researches have been carried out on the performance and emission characteristics of CAI engines but there are still some fundamental questions that are yet to be addressed such as in-cylinder process. In the present study, a Ricardo Hydra single cylinder, four stroke optical gasoline engine was instrumented to investigate CAI combustion through negative valve overlap configuration. The effects of direct fuel injection timings and direct air injection at lambda 1 were studied by means of simultaneous in-cylinder heat release study and high speed images of complete chemiluminescence emission, OH and CHO radicals. In particular, the minor combustion process during the NVO period with various air injection quantities was studied with both heat release analysis and chemiluminescence results. The charge cooling and local air/fuel ratio effects were also investigated by varying the quantity of direct injected air in an air assisted injector. Copyright © 2009 SAE International.

• Presentation Conference Type: Conference Paper (unpublished)
• Conference Name: SAE Technical Papers
• Start Date: Jun 8, 2009
• End Date: Jun 8, 2009
• Publication Date: Dec 1, 2009
• Journal: SAE
• Peer Reviewed: Not Peer Reviewed
• Book Title: In-Cylinder Studies of CAI Combustion with Negative Valve Overlap and Simultaneous Chemiluminescence Analysis
• DOI: https://doi.org/10.4271/2009-01-1103
• Keywords: alternative fuel, diesel/gasoline combustion, aftertreatment, engine control, optical engine
• Public URL: https://uwe-repository.worktribe.com/output/1006535
• Publisher URL: http://dx.doi.org/10.4271/2009-01-1103
• Additional Information: Title of Conference or Conference Proceedings : SAE World Congress & Exhibition