Abstract: A four-stroke internal combustion engine with at least two inlet valves and an inlet flow path with at least two inlet ports per cylinder which branch off from a common inlet pipe and are guided separately up to the inlet valves and of which at least one inlet port is designed as a charge loading port and at least one inlet port as a volumetric port, with a throttle device for volumetric control being provided in the inlet flow path and the inlet flow path is connected with a fuel supply device. In order to achieve in the simplest possible way an improvement of the exhaust gas quality at low fuel consumption, the fuel supply device is formed by a joint carburetor for both inlet ports, with preferably the carburetor being arranged in the zone of the branching of the inlet ports from the inlet pipe.

Abstract: A four cycle outboard internal combustion engine for driving a watercraft with a cylinder housing having cylinders arranged in at least two rows, wherein a piston is reciprocating in each cylinder, the pistons driving an approximately horizontally accommodated propeller drive shaft by way of an approximately vertically arranged crankshaft, each cylinder bank being provided with cylinder head sealing surfaces for a cylinder head housing receiving gas shuttle valves and wherein the cylinder head sealing surfaces of all of the cylinders are arranged in one single cylinder head sealing plane and an exhaust main manifold for all of the cylinders is arranged approximately parallel to the crank shaft in the cylinder head housing in the area of a central plane of the motor which is configured parallel to the crankshaft. One crankshaft is provided for each cylinder bank, the crankshafts having a stable relative speed ratio and acting upon the propeller drive shaft through a common jackshaft.

Abstract: The invention relates to a piston 1 for a four-stroke internal combustion engine, comprising a piston head 2 with a piston top 3 on the side of the combustion space, and a first groove 5 next to the piston top 3 holding a compression ring 9 and a second groove 6 further apart from the piston top 3 holding an oil scraper ring 22 being formed in the wall 4 of the piston head 2, and a piston ring land 7 being formed between the two grooves 5, 6, and further comprising a piston skirt 10 adjacent to the piston head 2, whose wall 11 includes first guide faces 12 for guiding the piston 1 in a cylinder, as well as a piston pin bore 13 carrying a piston pin 14. To reduce oil consumption and diminish frictional losses, it is provided that the ring land 7 between the two grooves 5, 6 be designed as second guide face 17 for guiding the piston 1.

Abstract: A drive unit for a motorcycle includes an internal combustion engine with at least two cylinders arranged in V-position, a clutch and a transmission, the transmission being located in the space between the cylinders.

Abstract: An exhaust system for internal combustion engines, in particular two-cycle internal combustion engines, includes a resonance-type exhaust part having at least one diffuser-cone unit formed with a diffuser, a countercone, and a connecting part with a preferably constant cross section extending between the diffuser outlet cross section and cone inlet cross section. In order to provide the resonance-type exhaust part as compact as possible by employing a simple production method, the connecting part is formed as a first deflection arc, preferably with an angle of deflection of about 180°±30°.

Abstract: In a reciprocating engine with at least two cylinders, with at least one primary connecting rod and at least one secondary connecting rod, whose small ends are connected to a piston each, the crankshaft ends of the connecting rods, i.e., the ends opposite of the small ends, are mounted on a common crank pin of a crankshaft. The crankshaft end of the primary connecting rod has a shoulder whose inner surface is rotatably connected to the crank pin via a first bearing, the outer surface of the shoulder defining a bearing surface for at least one secondary connecting rod. The inner and outer surfaces constituting the bearing surfaces of the essentially tubular shoulder extend around the full periphery and are configured as cylindrical surfaces preferably. The at least one secondary connecting rod has a crankshaft end with a non-divided divided big eye surrounding the shoulder of the primary connecting rod, the inner surface of which eye is supported on the outer surface of the shoulder via a second bearing.

Abstract: This invention relates to an internal combustion engine for a motorcycle, with two or more single cylinders arranged in a plane approximately normal to a crankshaft, each cylinder accommodating a reciprocating piston and the pistons acting via connecting rods on the same crank of the crankshaft supported in a crankcase. To reduce manufacturing expense, the engine is to be provided with modular components for universal use with at least two different cylinder arrangements (V-type, W-type).