Liquid hydrogen as a vehicular fuel—a challenge for cryogenic engineering

Present and developing technologies of liquid hydrogen onboard storage and handling are reviewed. Substantial improvement in operating hydrogen fueled internal combustion engines can be made by intense use of the cold hydrogen gas available from the LH₂-fuel tank. Because of the large heat sink capability of liquid hydrogen the volumetric heating value of the cylinder charge can be increased considerably even for external mixture formation. Further success in hydrogen engine development will depend mainly upon the development of suitable internal fuel mixing techniques based on cryogenic liquid fuel injection pumps.