The effect of combustion chamber geometry on injection and mixture preparation in a CNG direct injection SI engine

► The results show strong sensitivity to grid size across the nozzle diameter. ► Narrow bowl configuration showed to be best choice for charge stratification. ► Single-hole and multi-hole injectors exhibit positive characteristics for the flow. ► The influence of pentroof cylinder head occur towards the end of compression stroke. ► The pentroof cylinder head also forces a non-symmetrical flow field inside cylinder.