Abstract: The invention concerns a two-stroke internal-combustion engine with a charging pump, an outlet channel controlled by the main piston being subjected to additional control by the charging-pump plunger. Circulation losses are minimized and a higher means working pressure is obtained by early mechanical closure of the outlet channel by means of the charging-pump plunger or by injecting a pulse of exhaust gases into the outlet channel in the direction opposite to the direction of flow or by injecting part of the intake charge through the outlet channel into the main cylinder. In addition, the formation of oxides of nitrogen is reduced by controlled exhaust gas retention at the combustion stage. The invention also allows a catalytic converter to be used if required, since an increase in the oxygen concentration owing to circulation losses in the outlet channel is avoided.

Abstract: An aluminium 2-stroke engine cylinder and the crank case assembly is provided, in which a cylinder flange rests in sealing manner over its entire area upon a corresponding counter-surface of the crank case and a deformable packing lies between the sealing surfaces and in which the flange is tightened to the crank case by means of screws. The mutually opposite sealing surfaces of flange and crank case are slightly inclined in relation to one another in such a way that the distance between the sealing surfaces is greater radially inwards than radially outwards.

Abstract: A piston has a pair of support members extending away from the piston head offset from a piston ring portion, a piston rod being carried on a connecting rod which is clamped between the support members by a bolt. The bolt is loosely received in a bore in the connecting rod, the force between the piston and the piston rod being taken by a frictional force between the connecting rod and the support members to prevent a bending force being applied to the bolt.