face 31 onto which join wedge shaped side faces 32 tapered towards the rear it is important here that the middle 34 squish 34 space 19 is extended as far as possible in the direction of the spark plug 5 in order to lead a straight and directed short flow of the richer mixture directly onto the spark plug 5 to further simplify the formation of weaker and richer mixtures the complete mixture only is created by a carburettor or injection equipment and is weakened by the addition of combustible air before the valve 3 at the position 9 this additional air can be led in by an adaptor 8 between the inlet chamber and the cylinder head control is achieved by a throttle flap or similar valve which is linked to the control of the opening of the carburettor throttle flap at tick over of this engine the throttle flap for the additional air is closed instead of pure combustible air exhaust gas or a mixture of exhaust and combustible air can be substituted because of the imprecise separation of the layer charge in which the richer mixture and combustible air in the zone of disturbance during induction and compression phases experience a transitional mixing a thorough combustion of all fuel parts is ensured this achieves in the case of excess air which is not combustible without layer charging a very low consumption at minimal carbon monoxide hydrocarbon and nitrogen.