This paper investigates the performance of hydrogen-fueled, spark-ignited, single-cylinder Cooperative Fuel Research using experimental and numerical approaches. This study examines the effect of the air–fuel ratio on engine performance, emissions, and knock behaviour across different compression ratios. The results indicate that λ significantly affects both engine performance and emissions, with a λ value of 2 yielding the highest efficiency and lowest emissions for all the tested compression ratios. Combustion analysis reveals normal combustion at λ ≥ 2, while knocking combustion occurs at λ < 2, irrespective of the tested compression ratios. The Livenwood–Wu integral approach was evaluated to assess the likelihood of end-gas autoignition based on fuel reactivity, demonstrating that both normal and knocking combustion possibilities are consistent with experimental investigations. Combustion analysis at the ignition timing for maximum brake torque conditions demonstrates knock-free stable combustion up to λ = 3, with increased end-gas autoignition at lower λ values. To achieve knock-free combustion at those low λs, the spark timings are significantly retarded to after top dead center crank angle position. Engine-out NOx emissions consistently increase in trend with a decrease in the air–fuel ratio of up to λ = 3, after which a distinct variation in NOx is observed with an increase in the compression ratio.

Global warming is a major environmental issue caused by the release of greenhouse gases, such as carbon dioxide into the atmosphere. Light-duty vehicles (LDVs) including passenger cars and light-duty trucks, are a significant contributor to greenhouse gas emissions. The transportation sector is responsible for approximately 23% of global CO₂ emissions, with LDVs accounting for a substantial portion of these emissions. This paper aims to investigate the feasibility of zero-carbon fuels with focus on hydrogen and ammonia in spark ignition internal combustion engines for light-duty vehicles. With the increasing demand for sustainable and carbon-free mobility, alternative fuels such as hydrogen and ammonia are gaining attention as potential solutions. The properties and characteristics of these fuels and their potential for utilising them as a fuel in internal combustion engines are also reviewed. Current challenges and opportunities associated with the use of these fuels, including production, storage, and distribution, will be discussed. While there are still technical and infrastructural challenges that need to be addressed, hydrogen and ammonia have the potential to provide clean and efficient energy sources for light-duty vehicles. The development of these fuels, along with advancements in internal combustion engine technology, can help pave the way towards a carbon-free future for mobility.