An experimental and numerical investigation to characterize the low-temperature heat release in stoichiometric and lean combustion

Muhammad Waqas, Song Cheng, S. Scott Goldsborough, Toby Rockstroh, Bengt Johansson, Christopher P. Kolodziej

Research output: Journal article publicationJournal articleAcademic researchpeer-review

8 Citations (Scopus)


The low-temperature heat release (LTHR) characteristics of three RON 90 binary fuel blends (n-heptane blended with isooctane, toluene and ethanol) under lean and stoichiometric conditions that are representative of homogeneous charge compression ignition and spark-ignition end-gas combustion conditions, respectively, were studied using Cooperative Fuel Research (CFR) engine experiments as well as kinetic simulations. The end-gas temperature-pressure (T-P) trajectories were analyzed to identify the intake conditions leading to similar T-P trajectories between the two lambdas for each fuel blend. A heat release analysis was then conducted for the identified cases, where fuel-to-fuel differences in LTHR were identified and found to be sensitive to the operating condition. Simulations were conducted for these cases using a recently updated chemical kinetic model and a 0-D engine model, where good qualitative and reasonable quantitative agreements in LTHR were obtained. Sensitivity analysis was also performed directly on the rates of LTHR to understand the controlling chemical reactions of LTHR, providing further insights into the fuel-to-fuel differences. The results showed a significant promoting effect of n-heptane on LTHR rates, while inhibiting effects were observed for ethanol and toluene. Also highlighted was the importance of H-atom abstraction reactions from the chemistry of each fuel component, which could lead to contradictory fuel behavior depending on the locations of the H site of the abstraction reaction due to the different ensuing pathways for the primary fuel radicals.

Original languageEnglish
Pages (from-to)6221-6230
Number of pages10
JournalProceedings of the Combustion Institute
Issue number4
Publication statusPublished - Jan 2021
Externally publishedYes
Event38th International Symposium on Combustion, 2021 - Adelaide, Australia
Duration: 24 Jan 202129 Jan 2021


  • LTHR
  • RON 90 binary blends
  • Sensitivity analysis

ASJC Scopus subject areas

  • General Chemical Engineering
  • Mechanical Engineering
  • Physical and Theoretical Chemistry


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