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Favorable and unfavorable properties of hydrogen as a combustion engine fuel have been accommodated in a design of a fuel efficient and clean engine providing similar to gasoline maximum torque and power. The advanced H2ICE being developed is a turbocharged engine fitted with cryogenic port hydrogen fuel injection and the hydrogen assisted jet ignition (HAJI). The combustion chamber is designed to produce a high compression ratio and therefore high thermal efficiency. A waste gated turbocharger provides pressure boosting for an increased power density running ultra lean for SULEV operation without after treatment. Thanks to the combustion properties of hydrogen further enhanced by the HAJI system, the engine load is mainly controlled throttle-less decreasing the fuel-to-air equivalence ratio from ultra lean ϕ=0.43 to ultra-ultra lean ϕ=0.18. The computational model developed for addressing the major design issues and the predicted engine performance and efficiency maps are included.

Hydrogen assisted jet ignition (HAJI) is a pre-chamber ignition system for otherwise standard gasoline fueled spark ignition engines that involves the use of a chemically active turbulent jet to initiate combustion in lean fuel mixtures. HAJI burns the lean main charge rapidly and with almost no combustion variability, which allows for low hydrocarbon emissions and almost zero NOx, due to lower peak temperatures. This paper focuses on the effects of different pre-chamber fuels on combustion stability, lean limit and emissions in a single cylinder, HAJI equipped, CFR engine under a worst case, light load condition. Results indicate that the choice of pre-chamber fuel affects the main chamber lean limit but that emissions are not largely affected before this lean limit is reached. The lean limit was extended furthest, to λ = 2.5 with hydrogen, followed by λ = 2.35 with LPG, λ = 2.25 with CNG and λ = 2.15 with carbon monoxide.

Hydrogen assisted jet ignition (HAJI) is a pre-chamber ignition system for standard gasoline fueled engines that involves the use of a chemically active turbulent jet to initiate combustion in lean fuel mixtures. HAJI burns the lean main charge rapidly and with almost no combustion variability, which allows for low hydrocarbon emissions and almost zero NOx, due to lower peak temperatures. This paper focuses on the effects of internal and cooled external exhaust gas recirculation (EGR) on combustion parameters, emissions and thermal efficiency in a single cylinder HAJI equipped CFR engine. Experimental results indicate that replacing air with EGR in λ=2 mixtures can shift the lean limit at which NOx is negligible to mixtures as rich as λ=1.3, without a large penalty in hydrocarbon emissions and thermal efficiency.