A modeling and experimental study of the argon power cycle using mixing-controlled combustion
Gainey, Brian LU ; Ahrling, Christoffer LU
; Tunestål, Per
LU
and Tunér, Martin
LU
(2026)
In SAE Technical Papers
- Abstract
- The closed-cycle hydrogen-fueled argon power cycle is a zero emissions concept that combines a carbon-free fuel with argon as a diluent replacement for nitrogen. The lack of nitrogen in the argon power cycle results in zero NOx emissions on an internal combustion engine platform. There is also massive efficiency improvement because argon is monatomic and has a very high ratio of specific heats. However, this will also result in combustion temperatures and pressures exceeding those normally achieved on an air-standard engine platform. The literature shows conflict between modeling, which promises incredibly high efficiency gains, and experiment, which show more modest efficiency gains.
This work combined thermodynamic modeling,... (More) - The closed-cycle hydrogen-fueled argon power cycle is a zero emissions concept that combines a carbon-free fuel with argon as a diluent replacement for nitrogen. The lack of nitrogen in the argon power cycle results in zero NOx emissions on an internal combustion engine platform. There is also massive efficiency improvement because argon is monatomic and has a very high ratio of specific heats. However, this will also result in combustion temperatures and pressures exceeding those normally achieved on an air-standard engine platform. The literature shows conflict between modeling, which promises incredibly high efficiency gains, and experiment, which show more modest efficiency gains.
This work combined thermodynamic modeling, literature analysis, and experiments to understand this discrepancy and ultimately understand what level of efficiency gain can be expected for the argon power cycle. It was found that while low compression ratio engines stand to see the largest relative efficiency improvement, high compression ratio engines are the ones that can ultimately achieve ~60%+ efficiency, corresponding to a 15–20% relative improvement in efficiency over an air-standard engine platform operating at or above 50% efficiency. The elevated temperatures and pressures of the cycle result in knock in spark ignition, so either a high compression ratio knock mitigation strategy or mixing-controlled operation is required. Experiments conducted using a diesel-fueled compression ignition engine showed that a 30% argon replacement resulted in ~6% and full nitrogen replacement with argon resulted in ~14% relative efficiency improvement at 8 bar gross indicated mean effective pressure (IMEPg) without intake boosting on a heavy-duty engine with a compression ratio of 20.0 and late intake valve closing, agreeing with modeling results. The key takeaway to match modeling and experimental trends is to accurately model heat transfer, which increases significantly for the argon power cycle. (Less) - Abstract (Swedish)
- The closed-cycle hydrogen-fueled argon power cycle is a zero emissions concept that combines a carbon-free fuel with argon as a diluent replacement for nitrogen. The lack of nitrogen in the argon power cycle results in zero NOx emissions on an internal combustion engine platform. There is also massive efficiency improvement because argon is monatomic and has a very high ratio of specific heats. However, this will also result in combustion temperatures and pressures exceeding those normally achieved on an air-standard engine platform. The literature shows conflict between modeling, which promises incredibly high efficiency gains, and experiment, which show more modest efficiency gains.
This work combined thermodynamic modeling,... (More) - The closed-cycle hydrogen-fueled argon power cycle is a zero emissions concept that combines a carbon-free fuel with argon as a diluent replacement for nitrogen. The lack of nitrogen in the argon power cycle results in zero NOx emissions on an internal combustion engine platform. There is also massive efficiency improvement because argon is monatomic and has a very high ratio of specific heats. However, this will also result in combustion temperatures and pressures exceeding those normally achieved on an air-standard engine platform. The literature shows conflict between modeling, which promises incredibly high efficiency gains, and experiment, which show more modest efficiency gains.
This work combined thermodynamic modeling, literature analysis, and experiments to understand this discrepancy and ultimately understand what level of efficiency gain can be expected for the argon power cycle. It was found that while low compression ratio engines stand to see the largest relative efficiency improvement, high compression ratio engines are the ones that can ultimately achieve ~60%+ efficiency, corresponding to a 15–20% relative improvement in efficiency over an air-standard engine platform operating at or above 50% efficiency. The elevated temperatures and pressures of the cycle result in knock in spark ignition, so either a high compression ratio knock mitigation strategy or mixing-controlled operation is required. Experiments conducted using a diesel-fueled compression ignition engine showed that a 30% argon replacement resulted in ~6% and full nitrogen replacement with argon resulted in ~14% relative efficiency improvement at 8 bar gross indicated mean effective pressure (IMEPg) without intake boosting on a heavy-duty engine with a compression ratio of 20.0 and late intake valve closing, agreeing with modeling results. The key takeaway to match modeling and experimental trends is to accurately model heat transfer, which increases significantly for the argon power cycle. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/e99d8534-ba66-4a2c-a4e7-f03dc1733335
- author
- Gainey, Brian
LU
; Ahrling, Christoffer
LU
; Tunestål, Per
LU
and Tunér, Martin
LU
- organization
- publishing date
- 2026-06-19
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Low emission vehicles (LEV) and zero emission vehicles (ZEV), Diesel / compression ignition engines, Internal combustion engines, Spark ignition engines, Nitrogen oxides, Combustion and combustion processes, Heat transfer
- in
- SAE Technical Papers
- article number
- 2026-01-5043
- pages
- 13 pages
- publisher
- Society of Automotive Engineers
- external identifiers
-
- scopus:105042672586
- ISSN
- 0148-7191
- DOI
- 10.4271/2026-01-5043
- language
- English
- LU publication?
- yes
- id
- e99d8534-ba66-4a2c-a4e7-f03dc1733335
- date added to LUP
- 2026-09-08 13:32:56
- date last changed
- 2026-09-14 10:22:35
@article{e99d8534-ba66-4a2c-a4e7-f03dc1733335,
abstract = {{The closed-cycle hydrogen-fueled argon power cycle is a zero emissions concept that combines a carbon-free fuel with argon as a diluent replacement for nitrogen. The lack of nitrogen in the argon power cycle results in zero NOx emissions on an internal combustion engine platform. There is also massive efficiency improvement because argon is monatomic and has a very high ratio of specific heats. However, this will also result in combustion temperatures and pressures exceeding those normally achieved on an air-standard engine platform. The literature shows conflict between modeling, which promises incredibly high efficiency gains, and experiment, which show more modest efficiency gains.<br/><br/>This work combined thermodynamic modeling, literature analysis, and experiments to understand this discrepancy and ultimately understand what level of efficiency gain can be expected for the argon power cycle. It was found that while low compression ratio engines stand to see the largest relative efficiency improvement, high compression ratio engines are the ones that can ultimately achieve ~60%+ efficiency, corresponding to a 15–20% relative improvement in efficiency over an air-standard engine platform operating at or above 50% efficiency. The elevated temperatures and pressures of the cycle result in knock in spark ignition, so either a high compression ratio knock mitigation strategy or mixing-controlled operation is required. Experiments conducted using a diesel-fueled compression ignition engine showed that a 30% argon replacement resulted in ~6% and full nitrogen replacement with argon resulted in ~14% relative efficiency improvement at 8 bar gross indicated mean effective pressure (IMEPg) without intake boosting on a heavy-duty engine with a compression ratio of 20.0 and late intake valve closing, agreeing with modeling results. The key takeaway to match modeling and experimental trends is to accurately model heat transfer, which increases significantly for the argon power cycle.}},
author = {{Gainey, Brian and Ahrling, Christoffer and Tunestål, Per and Tunér, Martin}},
issn = {{0148-7191}},
keywords = {{Low emission vehicles (LEV) and zero emission vehicles (ZEV); Diesel / compression ignition engines; Internal combustion engines; Spark ignition engines; Nitrogen oxides; Combustion and combustion processes; Heat transfer}},
language = {{eng}},
month = {{06}},
publisher = {{Society of Automotive Engineers}},
series = {{SAE Technical Papers}},
title = {{A modeling and experimental study of the argon power cycle using mixing-controlled combustion}},
url = {{http://dx.doi.org/10.4271/2026-01-5043}},
doi = {{10.4271/2026-01-5043}},
year = {{2026}},
}