Fuel reformation by piston compression of rich air-fuel mixture

Abstract

The purpose of this paper is to investigate and describe the fuel reformation by diesel piston compression to change the ignitability of commercial fuels for marine engines. The engine operational conditions were first investigated by CHEMKIN Pro with n-heptane as a fuel, an HCCI engine with port fuel injection was operated by n-heptane based on simulation results, and the production of reformed gases (hydrogen, carbon monoxide, methane, and ethylene) were measured by emission analyzers. The fuel reformation becomes active above a 2.0 equivalence ratio and higher intake air temperature conditions, and the molar fractions of the reformed gases can be varied by the maximum in-cylinder average temperature during the reforming processes. An indirect injection diesel engine was newly introduced and the diesel fuel reformation characteristics were evaluated. Further, the fuel decomposition processes were investigated by CHEMKIN Pro. The results suggest that the hydrogen and carbon monoxide are produced via a number of production paths in the fuel decomposition into small hydrocarbons and chemical production controls of hydrogen and carbon monoxide will be difficult. However, the production paths of methane and ethylene formation are limited by the decomposition of hydrocarbons and this suggests the possibility of chemical production control of methane and ethylene.