The optimization of leading spark plug location and its influences on combustion and leakage in a hydrogen-fueled Wankel rotary engine

The hydrogen-fueled Wankel rotary engine with excellent power and emission characteristic is under spotlight, while the leakage is still the major problem for Wankel rotary engine, especially the leading spark plug leakage. The peak pressure is increased from 3.34 MPa to 3.52 MPa and the indicated thermal efficiency reaches maximum value of 38.29% when the moving distance of leading spark plug is −6.5 mm, and the mass of leakage fresh mixture is reduced from 0.00311 g to 0 g. When leading spark plug is moved to minor axis, the flow field structure of working chamber is enhanced. However, the peak pressure and indicated thermal efficiency decrease when the moving distance of leading spark plug exceeds −6.5 mm. The excess leakage residual gas has negative effects on combustion. The optimum moving distance of leading spark plug is −6.5 mm at 3000 rpm with λ of 1.6.