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An analysis of alcohol compression ignition strategies on different engine platforms

Gainey, Brian LU ; Lawler, Benjamin ; Bhatt, Ankur ; Vedpathak, Kunal ; Verhelst, Sebastian LU orcid ; Dejaegere, Quinten ; Tunér, Martin LU ; Dempsey, Adam ; Zeman, Jared and Johnston, Tyler , et al. (2026) In Fuel 426.
Abstract

Strategies that enable ignition of the low cetane alcohol fuels (methanol and ethanol) include intake heating (direct or via hot residual trapping), increased compression ratio (CR), multi-injection strategies, ignition enhancers, and active prechambers. The literature consistently shows alcohol compression ignition (CI) is more efficient than diesel at high loads irrespective of ignition strategy but shows contradictory results at low loads. To understand this, this work combines data from four different engine platforms ranging from a displaced volume of 0.4 to 2.1 L/cyl. using different alcohol CI ignition strategies. Using modeling to support experimental analysis, alcohol-specific efficiency penalties are highlighted to inform... (More)

Strategies that enable ignition of the low cetane alcohol fuels (methanol and ethanol) include intake heating (direct or via hot residual trapping), increased compression ratio (CR), multi-injection strategies, ignition enhancers, and active prechambers. The literature consistently shows alcohol compression ignition (CI) is more efficient than diesel at high loads irrespective of ignition strategy but shows contradictory results at low loads. To understand this, this work combines data from four different engine platforms ranging from a displaced volume of 0.4 to 2.1 L/cyl. using different alcohol CI ignition strategies. Using modeling to support experimental analysis, alcohol-specific efficiency penalties are highlighted to inform alcohol combustion system development. The alcohols’ lower energy density means more fuel must be injected near top dead center to achieve a given load, increasing the relative penalty of sensible/latent heating. Pilot injections help reduce this penalty. Intake heating incurs both a heat transfer penalty and a thermodynamic penalty due to a reduced ratio of specific heats during compression. A strategy that combines elevated CR, large pilot injections, and ignition enhancers can avoid this penalty. Alternatively, a prechamber strategy can achieve this without changing the CR, nor needing ignition enhancers in the fuel. At low loads, diesel burns in a partially premixed mode characterized by high burn rates and low heat losses, reducing alcohol-specific combustion benefits. Alcohol CI on the light-duty platform showed abnormally high heat transfer over diesel compared to other platforms, favoring a more premixed/partially premixed strategy despite a combustion efficiency tradeoff.

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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Fuel
volume
426
article number
139393
publisher
Elsevier
external identifiers
  • scopus:105036479717
ISSN
0016-2361
DOI
10.1016/j.fuel.2026.139393
language
English
LU publication?
yes
id
e36df44d-9b63-46e0-8fff-bbdb4596dbb0
date added to LUP
2026-06-23 14:57:15
date last changed
2026-06-23 14:57:53
@article{e36df44d-9b63-46e0-8fff-bbdb4596dbb0,
  abstract     = {{<p>Strategies that enable ignition of the low cetane alcohol fuels (methanol and ethanol) include intake heating (direct or via hot residual trapping), increased compression ratio (CR), multi-injection strategies, ignition enhancers, and active prechambers. The literature consistently shows alcohol compression ignition (CI) is more efficient than diesel at high loads irrespective of ignition strategy but shows contradictory results at low loads. To understand this, this work combines data from four different engine platforms ranging from a displaced volume of 0.4 to 2.1 L/cyl. using different alcohol CI ignition strategies. Using modeling to support experimental analysis, alcohol-specific efficiency penalties are highlighted to inform alcohol combustion system development. The alcohols’ lower energy density means more fuel must be injected near top dead center to achieve a given load, increasing the relative penalty of sensible/latent heating. Pilot injections help reduce this penalty. Intake heating incurs both a heat transfer penalty and a thermodynamic penalty due to a reduced ratio of specific heats during compression. A strategy that combines elevated CR, large pilot injections, and ignition enhancers can avoid this penalty. Alternatively, a prechamber strategy can achieve this without changing the CR, nor needing ignition enhancers in the fuel. At low loads, diesel burns in a partially premixed mode characterized by high burn rates and low heat losses, reducing alcohol-specific combustion benefits. Alcohol CI on the light-duty platform showed abnormally high heat transfer over diesel compared to other platforms, favoring a more premixed/partially premixed strategy despite a combustion efficiency tradeoff.</p>}},
  author       = {{Gainey, Brian and Lawler, Benjamin and Bhatt, Ankur and Vedpathak, Kunal and Verhelst, Sebastian and Dejaegere, Quinten and Tunér, Martin and Dempsey, Adam and Zeman, Jared and Johnston, Tyler and Chowdhury, Musharrat and Lee, Sanguk and Pintor, Dario Lopez}},
  issn         = {{0016-2361}},
  language     = {{eng}},
  publisher    = {{Elsevier}},
  series       = {{Fuel}},
  title        = {{An analysis of alcohol compression ignition strategies on different engine platforms}},
  url          = {{http://dx.doi.org/10.1016/j.fuel.2026.139393}},
  doi          = {{10.1016/j.fuel.2026.139393}},
  volume       = {{426}},
  year         = {{2026}},
}