Effects of Hydrocarbon with Different Ignition Properties and Hydrogen Blended Fuels on Autoignition and Combustion in an IC Engine 2023-01-1802

Hydrogen has attracted attention as one of the key fuels for making internal combustion engines carbon neutral. However, the combustion characteristics of hydrogen differ greatly from those of conventionally used hydrocarbons. Therefore, in order to develop next-generation internal combustion engines that operate on hydrogen, it is first necessary to have a thorough understanding of the combustion characteristics of hydrogen. Engines that can take maximum advantage of those characteristics should be developed on the basis of that knowledge. Toward that end, the purpose of this study was to investigate the fundamental combustion characteristics of hydrogen in a test engine. This paper presents the results of an investigation of the effects on low-temperature oxidation reactions and autoignition when hydrogen was blended into dimethyl ether (DME) [1, 2], a gaseous hydrocarbon fuel. Combustion experiments were conducted using a single-cylinder engine, and chemical kinetic simulations were performed. The experiments and simulations were carried out under homogeneous charge compression ignition (HCCI) conditions in order to investigate the fundamental reaction characteristics of DME and hydrogen. In the experiments, the input heat energy of hydrogen was increased while keeping that of DME constant so as to examine how blending with hydrogen would affect the reaction and combustion characteristics of DME. Chemical kinetic simulations were performed with Chemkin-Pro software to investigate the reaction kinetics of the experimental results. The results revealed that the ignition and combustion characteristics of the blended fuels used in the test engine were markedly different from those of hydrocarbon fuels because the reaction temperature region of hydrogen differed greatly from that of the latter fuels.