Abstract: A speed control system for an engine cooling fan has a planetary gearset, variably establishing a ratio between input and output speeds, and a hydraulic controller for changing the speed ratio according to engine operating conditions. Either one of a sun gear and pinion gear constitutes an input gear connected to an engine output of the engine. The other one of the sun gear and pinion gear is operationally coupled to a hydraulic control and a ring gear constitutes an output gear driving a rotary body. The hydraulic controller applies and varies an operational resistance to the planetary gearset according to engine operating conditions so as to cause it to vary the ratio of input and output speeds.

Abstract: A four-rotor type rotary piston engine including an eccentric shaft assembly composed of three elements; a main eccentric shaft defining the rotational axis of each rotor and first and second auxiliary eccentric shafts coupled to opposite end of the main eccentric shaft. The auxiliary eccentric shafts and the main eccentric shaft art fitted by tapered surfaces and have a small clearance therebetween in the radial direction to enable smooth coupling. The main eccentric shaft has two rotor eccentric journals for the second and the third cylinders. At first, the second and the third cylinders are installed. After that, the auxiliary eccentric shafts having rotor eccentric journals are coupled with the main eccentric shaft, and finally the first and the fourth cylinders are installed.

Abstract: A cooling system for a rotary piston engine including a radiator and a cooling liquid pump for forcing the cooling liquid to flow through the cooling liquid passages in the engine. The engine has a front cover provided at the axially front end of the engine for supporting accessories such as lubricant oil pump and an ignition distributor. The cooling liquid pump is provided in the front cover and connected with the cooling liquid passage in the engine through a supply passage which is also formed in the front cover.

Abstract: An engine lubricating system includes a lubricating oil supply mechanism having a plunger member adapted to be reciprocated in the axial direction in response to an engine output shaft to discharge lubricating oil, a control pin which is adapted to abut against the plunger member and is movable to change the stroke of the plunger member, thereby changing the discharge rate of the plunger member, and an electric actuator which moves the control pin to change the stroke of the plunger member. The engine operating condition is detected by way of at least both the engine load and the engine speed, and an electrical control unit outputs an electric control signal for controlling the electric actuator to change the discharge rate according to the engine operating condition.

Abstract: In an engine lubricating system in which a measured amount of lubricating oil is supplied to the combustion chamber of an engine by a metering oil pump so that a larger amount of lubricating oil is supplied to the combustion chamber when the engine load is heavy than when the engine load is light. The amount of the lubricating oil to be supplied to the combustion chamber per unit engine revolution is corrected to be larger at high engine speed than at low engine speed.

Abstract: A rotary piston engine including a casing comprised of three rotor housings, intermediate housings between the rotor housings and side housings attached to the outer sides of the outer side housings. An eccentric shaft assembly is provided for carrying rotors in the casing. The eccentric shaft assembly includes a first shaft and a second shaft which are connected together with one end of the second shaft located in one of the intermediate housings. The housings of the casing are connected together by first tightening bolts which are inserted through the housing at one side of the one intermediate housing and threaded to the one intermediate housing and second tightening bolts which are inserted through the housings at the other side of the one intermediate housing and threaded to the one intermediate housing.

Abstract: In a rotary piston engine comprising a casing having a pair of opposed inner side surfaces, and a rotor disposed in the casing and having opposite side surfaces confronting with said inner side surfaces of the casing, an oil seal assembly is positioned in an annular seal groove formed in each side surface of the rotor. The seal assembly comprises a seal ring having an annular lip adapted to be brought into sealing sliding engagement with the inner side surface of the casing, a bellows type spring connected at one end with the seal ring and an annular member connected to the other end of the spring and seated in the seal groove. An auxiliary seal is positioned between the annular member and the wall of the seal groove.

Abstract: A rotary piston engine has a housing structure which includes a peripheral wall, having a trochoidal inner surface, and end walls secured to the peripheral wall with the latter situated therebetween. A rotor, having each end face formed with at least one set of side seal grooves and at least one oil seal groove, is housed within the housing structure for planetary motion. For avoiding leakage of blowby gas from any one of working chambers defined between the rotor flanks and the trochoidal inner surface into the inside of an oil seal in the oil seal groove past side seals in the side seal grooves, an annular gas groove is formed on at least one end face of the rotor. This annular gas groove is communicated to the oil seal groove by means of a passage formed in a partition wall separating the gas groove from the oil seal groove.

Abstract: A corner seal member for use in a rotary internal combustion engine is constructed with an apex seal groove and an elongated cavity. The elongated cavity forms a thin wall having a substantially semicircular cross-section in the opposite side of the apex seal groove. The gas pressure delivered into the elongated cavity is advantageously used for urging the corner seal towards the inner surface of the corner seal groove, thereby preventing the gas pressure from leaking into an adjacent working chamber.

Abstract: In rotary piston engines including apex seals each comprising a main body constituting a substantial part of the seal, an end piece disposed in abutting relationship to an end of the main body through slanted cam surfaces which serve to force the end piece axially outwardly to engage with the inner surface of the side housing when the end piece is resiliently biased radially outwardly by spring means, the method of assembling the apex seals in the rotary piston engine, which comprises providing a projection of consumable material between the main body of each seal and the spring means so as to retain the spring means preventing the end piece from being displaced over the end face of the center housing, the consumable material being of such a type that dissipates under heat produced during engine operation.

Abstract: Rotary piston type internal combustion engine including corner seals adapted to be received in corner seal recesses provided in each corner portion of a rotor, said corner seal comprising a substantially cylindrical body, an axial bore of circular cross-section axially offset from the axis of the body, and a substantially radially extending slot provided in the body at the side opposite to the direction of offset of the bore so as to define a substantially C-shaped cross-section of varying wall thickness. The configuration of the corner seal is effective to provide it with radial resiliency and also ensure uniform contact pressure against the wall surface of the recess throughout the periphery thereof.

Abstract: A rotary piston of a rotary piston internal combustion engine has radially and inner and outer annular seals carried within grooves of the rotary piston thrust surface axially facing the engine casing sidewall with the axial end face of the oil seal tapering radially outwards relative to the engine sidewall and forming lip angles between the tapered end wall of the seal such that the lip angle for the outer seal is between 1.degree. and 3.degree., the lip angle for the inner seal is between 3.degree. and 5.degree., and the spring biasing force acting on the radially outer seal is less than that acting on the radially inner seal. Preferably, an oil removal bore is formed in the land portion between the grooves for return of the oil delivered thereto by action of the oil seal to the oil pan of the engine.