Numerous studies have demonstrated the advantages of hydrogen as a fuel for Otto Cycle engines due to high thermal efficiency and low exhaust pollutant levels. Characteristic of hydrogen engine operation using pre-mixed intake charge formation is a problem of pre-ignition resulting in an intake manifold backfire. Additional problems include high NO production when using certain equivalence ratios and power output degradation due to low fuel energy/volume density.
Techniques for direct and manifold fuel injection are discussed as means for overcoming these problems. Emphasis is placed on the need for total engine control, integrating control of fuel injection, ignition timing, intake air throttling, and vehicle subsystems within a central electronic unit. An electronically actuated fuel injection valve and a prototype electronic control system are developed. These are applied in manifold and direct injection system geometries, and evaluated in engine testing. System effectiveness and feasibility are discussed. v
