Effect of boundary on homogeneous charge compression ignition engine fueled with anode off-gas and refueled anode off-gas

Abstract

Hybrid solid oxide fuel cells and internal combustion engine systems are one of the most efficient power plants for low-carbon fuels. But the utilization of anode off-gas was a challenge. Homogeneous charge compression ignition has the advantage for such dilute and high-temperature fuels of 800 K∼ 1000 K and 80% inert gases, but easily influenced by intake temperature, pressure and composition. Based on 1-D model coupled with detail methane-air mechanism. Insights into engine performance combining thermodynamic trajectory and CA50 iso-contour on the PT domain for combustion of anode off-gas and refueled off-gas was provided. Results show that refueling strategy would benefit indicated mean effective pressure and misfire, but had little effect on thermal efficiency, and increase the possibility of knock and emissions by autoigniting in advanced and increased fuel reactivity. Exhaust gas recirculation strategy helped operate at low-temperature and low-pressure with refueling strategy. The overlapping safe zone implies the safe temperature and pressure for engine fueled with anode off-gas to add new fuel. As equivalence ratio increased, the thermal efficiency first increased and then decreased, peaking at 0.3. Although the combustion of the compression ratio of 17.1 is higher than that of the compression ratio of 8.2, the thermal efficiency and knock trend is worse.