The optimised mixture formation for hydrogen fuelled engines

Both intake port injection type and in-cylinder injection type hydrogen fuel supply systems are designed for a single-cylinder research engine to investigate the effect of mixture formation on the performance of the hydrogen-fuelled engines. The intake port injection is superior in thermal efficiency and engine operation stability at low load conditions. However, the in-cylinder injection is superior for high load condition. In an engine experiment with throttling condition, the engine with intake port injection operates more stably and efficiently when fuel-air equivalence ratio is maintained above a certain level despite the pumping loss due to stable combustion. Thus, the hydrogen-fuelled engines can be operated more stably with the in-cylinder injection at high load and more efficiently with the intake port injection at low load. Therefore, the optimised operation of the hydrogen-fuelled engines can be achieved with a dual injection system and throttle valve control. (C) 2000 International Association for Hydrogen Energy. Published by Elsevier Science Ltd. All rights reserved.