The use of ammonia as a zero carbon heavy duty IC engine fuel for low criteria pollutant emissions– Simulation of an I.C. Engine with exhaust reforming

Heaton, David; Cairns, Alasdair

Abstract

Ammonia has many advantages for use as a net-zero fuel, primarily potentially lowest lifecycle cost and reasonable energy storage density (by volume) compared with other zero carbon contenders. Handling and safety is not without concern, but its safe use is not unprecedented, and studies have been done concluding it could be used with acceptable safety compared with existing fuels. An area requiring demonstration however is the achievement of adequately low levels of emissions for higher regulated countries (HRC1) such as Heavy duty Euro VI, or non-road Stage V in a reciprocating IC engine and the necessary aftertreatment requirements. The purpose of this paper is to present a possible approach using exhaust heat to partially reform ammonia back into hydrogen and nitrogen. This provides the (hydrogen) promoter fuel required for sufficiently rapid and stable SI combustion, and allows, for example, lambda = 1 combustion so that criteria pollutants and ammonia slip can probably be controlled to low levels by simple three-way catalyst. The various trade-offs are shown which control the reforming reactions using exhaust heat, which being endothermic can result in a net gain of fuel energy between fuel supply and the mixture entering the cylinder. The importance of good heat transfer from the exhaust to the fuel to be reformed is shown. The overall system is then compared in 1d simulation with a lean burn port injected hydrogen engine demonstrating the trade-offs for relative overall efficiency, airsystem requirements and in-cylinder component temperatures. It is concluded that many of the obstacles associated with ammonia IC engine combustion with low criteria pollutants may be possible to overcome, but hardware demonstration is now required.

Citation

Heaton, D., & Cairns, A. (2025). The use of ammonia as a zero carbon heavy duty IC engine fuel for low criteria pollutant emissions– Simulation of an I.C. Engine with exhaust reforming. Fuel, 384, Article 133538. https://doi.org/10.1016/j.fuel.2024.133538

• Journal Article Type: Article
• Acceptance Date: Nov 28, 2024
• Online Publication Date: Dec 10, 2024
• Publication Date: Mar 15, 2025
• Deposit Date: Jan 24, 2025
• Journal: Fuel
• Print ISSN: 0016-2361
• Electronic ISSN: 1873-7153
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 384
• Article Number: 133538
• DOI: https://doi.org/10.1016/j.fuel.2024.133538
• Public URL: https://nottingham-repository.worktribe.com/output/44428274
• Publisher URL: https://www.sciencedirect.com/science/article/pii/S0016236124026875?via%3Dihub