Inter-cycle variability of ignition delay in an ethanol fumigated common rail diesel engine

Bodisco, Timothy A., Trondle, Philipp, & Brown, Richard J. (2015) Inter-cycle variability of ignition delay in an ethanol fumigated common rail diesel engine. Energy, 84, pp. 186-195.

[img] Accepted Version (PDF 548kB)
Administrators only until 1 May 2017 | Request a copy from author

View at publisher


An experimental study has been performed to investigate the ignition delay of a modern heavy-duty common-rail diesel engine run with fumigated ethanol substitutions up to 40% on an energy basis. The ignition delay was determined through the use of statistical modelling in a Bayesian framework this framework allows for the accurate determination of the start of combustion from single consecutive cycles and does not require any differentiation of the in-cylinder pressure signal. At full load the ignition delay has been shown to decrease with increasing ethanol substitutions and evidence of combustion with high ethanol substitutions prior to diesel injection have also been shown experimentally and by modelling. Whereas, at half load increasing ethanol substitutions have increased the ignition delay. A threshold absolute air to fuel ratio (mole basis) of above ~110 for consistent operation has been determined from the inter-cycle variability of the ignition delay, a result that agrees well with previous research of other in-cylinder parameters and further highlights the correlation between the air to fuel ratio and inter-cycle variability.

Numerical modelling to investigate the sensitivity of ethanol combustion has also been performed. It has been shown that ethanol combustion is sensitive to the initial air temperature around the feasible operating conditions of the engine. Moreover, a negative temperature coefficient region of approximately 900{1050 K (the approximate temperature at fuel injection) has been shown with for n-heptane and n-heptane/ethanol blends in the numerical modelling. A consequence of this is that the dominate effect influencing the ignition delay under increasing ethanol substitutions may rather be from an increase in chemical reactions and not from in-cylinder temperature. Further investigation revealed that the chemical reactions at low ethanol substitutions are different compared to the high (> 20%) ethanol substitutions.

Impact and interest:

1 citations in Scopus
Search Google Scholar™
1 citations in Web of Science®

Citation counts are sourced monthly from Scopus and Web of Science® citation databases.

These databases contain citations from different subsets of available publications and different time periods and thus the citation count from each is usually different. Some works are not in either database and no count is displayed. Scopus includes citations from articles published in 1996 onwards, and Web of Science® generally from 1980 onwards.

Citations counts from the Google Scholar™ indexing service can be viewed at the linked Google Scholar™ search.

ID Code: 82212
Item Type: Journal Article
Refereed: Yes
Additional URLs:
Keywords: Ignition delay, Ethanol fumigation, Bayesian Modelling, Markov-chain Monte Carlo
DOI: 10.1016/
ISSN: 1873-6785
Divisions: Current > Schools > School of Chemistry, Physics & Mechanical Engineering
Current > Research Centres > Sustainable Built Environment National Research Centre
Current > QUT Faculties and Divisions > Science & Engineering Faculty
Copyright Owner: Copyright 2015 Elsevier
Deposited On: 05 Mar 2015 22:27
Last Modified: 14 Dec 2015 07:34

Export: EndNote | Dublin Core | BibTeX

Repository Staff Only: item control page