Design of a pre-chamber for IC engines operating on low pressure hydrogen

During the last decade there have been carried out studies in Iceland considering electrolytically produced hydrogen as a candidate fuel to replace imported oil. A part of these studies is an ongoing attempt to run an IC engine on low pressure hydrogen. The paper describes this attempt. The main results obtained are that hydrogen admission and ignition in a pre-chamber is a feasible solution for hydrogen combustion in IC engines. A pre-combustion chamber has been designed and built. There hydrogen at 2 bar absolute pressure is admitted to the engine cylinder through the pre-chamber during the suction stroke, controlled by a hydraulically operated hydrogen inlet valve. The mixture far the ignition is made by a jet of lean mixture entering the pre-chamber in the compression stroke. Test runs show that this approach fulfils the requirements of safety and robustness for the operation on low pressure hydrogen. Stable running is obtained down to theoretical air ratio 2.1, where the exhaust temperature is close to 500 degrees C.