To attain the lowering of a pump function for reduction in fuel consumption by disposing a fuel injection element near an ignition means, and fitting at least one of a plurality of suction elements so as to have a longitudinal axis in proximity to the longitudinal axis of a cylinder.

This engine involves the top surface of a piston 2, and a combustion chamber 1 formed by a cylinder 3 and a cylinder head 4, whereas a suction element 6 is disposed so that its axial line may be substantially parallel to the longitudinal axis X-X' of the cylinder 3 and at a position in proximity to the longitudinal axis X-X'. An ignition means 7 and a fuel injection element 8 are disposed near the suction element 6. The ignition means 7 is disposed preferably above a fuel injection element 8, or at a position near a suction line 5 and near the center of the combustion chamber 1. The exhaust line 9 is disposed on the central surface on the opposite side of a suction part and with its axis YY' inclined to the axis XX' of the cylinder.