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The paper reports and evaluates the combustion pressures of electrolytically produced stoichiometric hydrogen-oxygen mixtures, spark-ignited inside a variable height (volume 0-250cc) ceramic piston cylinder arrangement. Ignition of mixtures was carried out at room temperature and absolute pressures varying between 5 and 180 kPa. Maximum combustion pressures were obtained from pressure-time traces and compared to a computer simulation model based on the first law of thermodynamics, ideal gas law and high temperature dissociation of combustion products. Ignition delay time and rate of pressure rise are also investigated. The results are to be used in a preliminary design of a combustion chamber of a hydrogen-oxygen fuelled engine. It was found that maximum combustion pressures are dependent on initial mixture pressure, initial water vapour content and surface area/volume ratio of combustion chamber.

An engine driven high-pressure micro-compressor has been developed which employs a unique driving principle. Its advantages make it ideal for supplying high-pressure gaseous fuel to direct injection gas engines. Possible arrangements of the compressor within the engine's fuel supply system are described. The ideal operating cycle of the compressor is described. A mathematical model based on the ideal thermodynamic cycles of the compressor and engine has been developed to predict its performance characteristics. The results presented show that this type of analysis gives an accurate prediction of the compressor cylinder pressure versus engine crank angle in comparison with experimental data.