Study on Hydrogen Internal Combustion Stirling Engine (2nd Report, Investigation of Characteristics of the Hydrogen Internal Combustion Engine by Steam Injection Experiments)

Abstract

Characteristics of hydrogen internal combustion Stirling engine were analyzed by comparing the engine performances on steam injection and H2-O2 injection. The experimental results of the steam injection showed that the internal conversion efficiency and pressure ratio increased to comparable levels with H2-O2 injection. Also, a two-space model predicted the concentration of steam in high temperature space to be around 3% from the pressure rises in the steam injection and the H2-O2 injection experiment. Simulations and estimations on these characteristics suggested a large amount of steam condensed and the condensed water evaporated at the regenerator in a cycle, leading to the conclusion that the performance improvement in the hydrogen internal combustion Stirling engine was caused by not only temperature increase in the expansion space but also the condensation-evaporation of water at the regenerator.