Parametric Study of Methanol Combustion Assisted by Glow Plug in a Low-Duty Diesel Engine

This work numerically investigated the feasibility of methanol compression ignition combustion for light-duty diesel engine applications by using a glow plug (GP) to promote ignition. A comprehensive parametric study was conducted to assess the combustion characteristics depending on the GP position, the relative angle between the GP and injector, and other initial conditions. Optimal design parameters were identified. It was demonstrated that GP can enable successful ignition and combustion of methanol at the operating conditions under study. Among the many parameters considered, the relative angle between the GP and injector was found to be one of the most critical parameters in controlling the ignition and complete combustion. Increasing intake temperature promoted combustion speed and engine performance, but excessively high intake temperatures led to higher wall heat transfer loss and lower ITE. An appropriate level of the pilot injection mass was found to increase ITE, with the minimum loss of combustion efficiency attained at a pilot mass fraction of 10%. Increasing the intake pressure further improved the engine performance, primarily owing to the reduced wall heat transfer loss. In contrast, the combustion was not significantly affected by the change in injection pressure, although slightly higher ITE was obtained at the lower injection pressure. It is expected that higher thermal efficiency is achievable with further optimization of design parameters.