Theoretical investigation of the effects of using twin spark-plugs in a spark ignition engine on combustion and engine performance characteristics

In this thesis, the effects of using of twin spark-plugs and variation of plug locations on a spark-ignition engine combustion and performance characteristics were theoretically investigated by using a quasi-dimensional thermodynamic engine cycle model.In this study, solid model software was used for determination of geometric properties of developing spherical flame front. This offers the opportunity to use of real engine combustion chamber geometry with different number and locations of spark plugs on cylinder head.In the study, centrally located single plug, mid-radius located twin spark-plugs and mid-radius located single plug configurations were chosen as design parameters and equivalence ratio, spark advance and engine speed were varied as operating parameters.From the results of the study, it has been determined that the geometry having centrally located spark plug gives the best combustion and performance characteristics. The using of twin spark-plugs gives closer combustion and performance characteristics due to increasing combustion speed. The mid-radius located single spark geometry gives the worst characteristics since it has the longest flame travelling length.