Abstract: Valve seat inserts of a four-cycle internal-combustion engine are cooled by the lubricating oil of the oil circulating system. An oil duct extending in the camshaft housing is bored in such a manner that the lubricating oil flows from the oil duct into a ring duct surrounding the valve seat inserts. By means of a projection which closes off the ring duct, a forced flow around the valve seat insert is achieved before the lubricating oil flows out of the ring duct through an opening located close to the lubricating oil inlet. From the ring duct the lubricating oil flows through a discharge pipe to the camshaft where it is sprayed on the cams.

Abstract: A helicopter equipped with a reciprocating piston internal combustion engine in which an override clutch is arranged in a drive connection between the internal combustion engine and a rotor drive, is equipped with separate first and second electric motor starter devices (screw-push starters). A starter operation takes place in two phases whereby in a first phase initially the rotor drive is brought to a rotor synchronous rotational speed syn by means of the first starter device and in a second phase the internal combustion engine is started by means of the second starter device. When the internal combustion engine exceeds the idling rotational speed nl, the override clutch establishes the power-flow connection between the internal combustion engine and the rotor drive. Both phases can be carried out manually as also by a partly automatic or fully automatic control system on the basis of key depression.

Abstract: A helicopter is driven by means of a rotor that is connected with an internal-combustion engine. The air-cooled internal-combustion engine has a horizontally opposed construction and is arranged within walls of a cabin of the helicopter. In order to supply the internal-combustion engine with cooling air and intake air, air inlet openings are provided at the side walls of the cabin. For the discharge of the cooling air, outlet openings are arranged at the underside of the cabin.

Abstract: A valve guidance for an exhaust gas valve in the form of a disk valve of an internal combustion engine which is used for the control of an exhaust gas channel of an internal combustion engine; a guide body with good heat-conducting and sliding properties serves as valve guidance. The guide body is coated at the inlet place of the valve stem either with a hard metal coating applied by plasma-spray process or with a hard metal sleeve.

Abstract: A continuously operating fuel injection installation which includes an air-quantity measuring device in the suction pipe and a fuel-quantity distributor controlled thereby, is equipped for use with a multi-cylinder aircraft engine, with an auxiliary device that serves to achieve the best possible power output, fuel economy and flight safety; for that purpose, a height control pressure regulator is connected to the control pressure line leading to the fuel-quantity distributor in parallel to a warm-up regulator, which meters the control pressure and therewith the fuel admixture corresponding to the air density changing with temperature and pressure; by interconnecting a fixed throttle between the control pressure line and the fuel return line to the fuel tank, an emergency operation of the engine is assured in case of failure of both regulators.

Abstract: In an air quantity measuring device for a continuously operating fuel injection system, the baffle plate which actuates the control piston of the fuel quantity distributor by way of a lever, is provided with a raised portion on the inflow side thereof; to reduce the air-resistance of the baffle plate in a predeterminable manner, the peak of the raised portion is disposed eccentrically to the baffle plate in the lever-side half thereof, whereby the same air quantity measuring devices can be used for different measuring ranges by installing baffle plates with differently shaped raised portions.

Abstract: A reciprocating lens-like combustion space is formed in a piston internal combustion engine which is located with approximately one-half in a recess of the piston top and with approximately the other half in the cylinder head. By the dimensioning of the combustion space and the coordination thereof to the inlet and exhaust valve, a vortex flow is produced with a ring-shaped mixing zone of high fuel concentration, in which the ignition electrodes of two spark plugs are arranged diametrally opposite one another.

Abstract: A fuel injection system for a multi-cylinder aircraft engine in which, in order to secure the fuel supply, a pressure-measuring device is connected to the feed line leading from the fuel tank to the fuel quantity distributor, into which are installed two parallel fuel pumps and a fuel filter; this pressure-measuring device in case of a predetermined pressure drop switches on the fuel pump which previously was not in operation; in case of an excessive pressure difference at the fuel filter which is measured by pressure-measuring device upstream and downstream of the filter, an electromagnetic valve installed into a bypass line to the fuel filter is opened; the soiling degree of the fuel filter is indicated by a hydraulically actuated difference pressure-measuring device with pressure limitation.