Theoretical investigation on combustion characteristics of ethanol-fueled dual-plug SI engine

In this study, effects of equivalence ratio, spark timing and spark plug number and locations on combustion characteristics were theoretically investigated using an ethanol-fueled dual-plug SI engine. Two-zone quasi-dimensional model was used throughout analyses. Three spark plug configurations (diagonally, centrally and side located), three equivalence ratios (0.8, 0.9, and 1.0), and three spark timings (-30, -25, and -20 CA @ BTDC) were considered to analyze variation of total burn duration, mass fraction burned, cylinder pressure, and temperatures (exhaust and maximum burned gas). Variation of mass fraction burned and cylinder pressure were also investigated at lean mixture ratio and 2800 rpm (MBT engine speed). Lastly, the effect of engine speed on total burn duration, maximum cylinder pressure and aforementioned temperatures were investigated in the range of 1000-6000 rpm. The findings show that dual-plug configuration yields approximate combustion characteristics by comparison with centrally located single plug configuration in ethanol-fueled SI engine.