Hydrogen has been attracting attention as a useful fuel to improve state of environmental pollution and resource depletion by using fossil fuels. In internal combustion engines, which are widely used as conventional technologies, the hydrogen fuel can be applied. Since minimum ignition energy of hydrogen is lower than that of other fuels, the hydrogen fuel tends to cause abnormal combustion. However, the abnormal combustion is easily controlled in a rotary engine. In this study, therefore, a hydrogen rotary engine (HRE) was developed. For improving stability and output power of the 20cc HRE, combustion pressure sensor was adopted to measure combustion pressure in the 20cc HRE. Combustion pressure of the 20cc HRE at high load was decreased with delay of the ignition timing. Maximum torque was 0.24 Nm at BTDC 5 °. Exhaust gas temperature of the 20cc HRE was increased with delay of the ignition timing. On the other hand, thermal efficiency of the 20cc HRE was improved.
