バイオマス熱分解ガスを用いるディーゼルエンジンに関する研究

抄録

The composition of the biomass producer gas varies for the resource of biomass and the gasification method. In order to establish the operation guideline for dual fuel engines with a traditional injection system to use such gas fuels, the effects of the gas composition, pilot injection quantity and EGR on engine performance and emissions were investigated in experiments. The various mock biomass producer gases consisting of H₂, CH₄, CO, N₂ and CO₂ were supplied by mass flow controllers to a direct-injection diesel engine with a jerk type fuel injection pump. JIS 2 type diesel was also used for pilot fuel. It is clarified that the laminar burning velocity is useful index to estimate the operating range regardless of the gas composition, although the suitable equivalence ratio to ensure the stable operation varies according to the gas composition. The laminar burning velocity of over 40 cm/s at the TDC condition is a qualification to keep stable engine operation. At lower loads, EGR improves combustion and leads to the higher thermal efficiency, although it decreases the thermal efficiency because of its lower degree of constant volume at medium loads. In addition, the effect of EGR is small for the fuel with lower hydrogen content.