Jet squish motion in a homogeneous-charge spark-ignition engine fueled by natural gas
department or school: Applied Science, Faculty of
department or school: Mechanical Engineering, Department of
data provider: DSpace
degree campus: UBCV
creator: Kastanis, Eric James
issued: 2010-12-23T19:59:10Z
issued: 2010
related degree: Master of Applied Science - MASc
degree grantor: University of British Columbia
description: Squish is one of the fundamental types of in-cylinder charge motion, and has been shown to be important in the generation of turbulence during the compression stroke. Turbulence intensity positively affects the mixture burning speed, which is important with inherently slow combustion systems, such as lean-burn. A previously proposed novel chamber design called ‘squish jet’ has been reported to further increase turbulence intensity compared with conventional combustion chamber designs. One bowl-in-piston (BIP) and two squish jet pistons (SJA and SJB), each with differing piston bowl geometry, were designed and built, and the operational characteristics of each were extensively investigated in an instrumented homogeneous-charge spark-ignition engine fueled by natural gas. The entire operating map of each chamber design was explored at 1500, 2000, and 2500 rpm and under naturally aspirated and supercharged inlet conditions (1.75 bar MAP). Test results showed that neither the SJA nor the SJB chamber conclusively exhibited superior brake thermal efficiency compared to the baseline BIP chamber. The observed differences were within the experimental uncertainty on the brake specific fuel consumption (BSFC) and air-fuel ratio parameters. Supplemental analysis of combustion heat release and exhaust hydrocarbon emission indicated that the SJA chamber exhibited the poorest BSFC performance. Because of uncertainty on BSFC and air-fuel ratio, NOx emission differences could neither be conclusively defined. The SJB chamber was found to result in the lowest exhaust hydrocarbon emission. Performance differences were similar under naturally aspirated and supercharged conditions. The main combustion duration of the three chambers was comparable, while the squish jet chambers exhibited longer ignition delay than the BIP chamber, and therefore favoured advanced ignition timing. Limit diagram analysis of the three chambers showed that the SJB chamber exhibited a limit space of comparable …
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/30480
note: JET SQUISH MOTION IN A HOMOGENEOUS-CHARGE SPARK-IGNITION ENGINE FUELED BY NATURAL GAS by ERIC JAMES KASTANIS B.A.Sc., The University of British Columbia, 2004 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF APPLIED SCIENCE in THE FACULTY OF GRADUATE STUDIES (Mechanical Engineering) THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver) December 2010 !Eric James Kastanis, 2010 ii Abstract Squish is one of the fundamental types of in-cylinder charge motion, and has been shown to be important in the generation of turbulence during the compression stroke. Turbulence intensity positively affects the mixture burning speed, which is important with inherently slow combustion systems, such as lean-burn. A previously proposed novel chamber design called ?squish jet? has been reported to further increase turbulence intensity compared with conventional combustion chamber designs. One bowl-in-piston (BIP) and two squish jet pistons (SJA and SJB), each with differing piston bowl geometry, were designed and built, and the operational characteristics of each were extensively investigated in an instrumented homogeneous-charge spark-ignition engine fueled by natural gas. The entire operating map of each chamber design was explored at 1500, 2000, and 2500 rpm and under naturally aspirated and supercharged inlet conditions (1.75 bar MAP). Test results showed that neither the SJA nor the SJB chamber conclusively exhibited superior brake thermal efficiency compared to the baseline BIP chamber. The observed differences were within the experimental uncertainty on the brake specific fuel consumption (BSFC) and air-fuel ratio parameters. Supplemental analysis of combustion heat release and exhaust hydrocarbon emission indicated that the SJA chamber exhibited the poorest BSFC performance. Because of uncertainty on BSFC and air-fuel ratio, NOx emission differences could neither be conclusively defined. The SJB chamber was found to iii result in the lowest exha…
has type: Thesis/Dissertation
date issued: 2011-05
is shown at: 10.14288/1.0071549
language: eng
degree discipline: Mechanical Engineering
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivatives 4.0 International
rights URI: http://creativecommons.org/licenses/by-nc-nd/4.0/
scholar level: Graduate
type: Text
identifier URI: http://hdl.handle.net/2429/30480