Use this URL to cite or link to this record in EThOS:
Title: Partially premixed combustion in an optically accessible compression ignition engine
Author: Touloupis, Dimitris Panagiotis
ISNI:       0000 0004 7658 5535
Awarding Body: Imperial College London
Current Institution: Imperial College London
Date of Award: 2018
Availability of Full Text:
Access from EThOS:
Access from Institution:
This thesis sets out the high-speed imaging and Laser Induced Incandescence (LII) work carried out on the Ricardo Hydra and the Volvo D5 single cylinder optical light duty diesel engines at Imperial College London. A literature review was presented on diesel engine operation strategies along with a review on the optical diagnostic techniques used for the purpose of the present thesis. The experimental work on the Ricardo Hydra optical engine comprises three different experimental campaigns, which investigate three major engine operation strategies, commonly employed by engine manufacturers, namely inlet air dilution, pilot injection and post injection. The analysis identifies combustion patterns and characteristics and describes how these were affected when different operation strategies were employed. The investigation focused on soot emissions formation and their evolution throughout the combustion event. Most importantly, the employed operation strategies were evaluated in regard to their efficiency in reducing engine-out soot emissions. The experimental work on the Volvo D5 optical engine focused on the effect of injection timing and of a close-coupled pilot injection on combustion stratification and soot formation at operating conditions that promote PPC operation. Findings were analysed via means of pressure trace and apparent rate of heat transfer analyses, as well as a series of optical diagnostics techniques, namely high-speed flame natural luminosity imaging, CH* and C2* line-of-sight chemiluminescence, as well as planar Laser Induced Incandescence (pLII). Overall, results suggest that longer ignition delay is a key parameter in lower engine-out soot emissions, which can be achieved by several operating techniques. Longer ignition delay leads to enhanced in-cylinder mixing, which facilitates operation in the Partially Premixed Combustion regime, where fuel-rich areas can be eliminated, and soot formation weakens.
Supervisor: Taylor, Alex ; Jones, William Sponsor: European Commission
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral