Abstract: A power unit provided with a dry sump type lubricating device includes a power unit case that is covered in part by a power unit case cover and is divided into a front unit case and a rear unit case. The power unit also includes a crankshaft rotatably supported by a crank chamber that is formed by the power unit case and a shift shaft rotatably supported by a transmission chamber that is provided adjacent to the crank chamber. The power unit also includes an oil tank disposed on the crank chamber side of an anteroposterior outside surface of the power unit case cover and a hydraulic control device for controlling a shift clutch, disposed on the transmission chamber side of the anteroposterior outside surface of the power unit case cover.

Abstract: The number of constituent parts for an oil filter fixing system such as a bracket, are reduced, and the oil leaks during filter element exchange are avoided. The oil filter fixing system comprises a V bank of a V type engine, a crankcase fixed with the V bank and an oil filter fixed with the crankcase. A horizontal fixing plane is formed at a part of an outer surface of the crankcase and the oil filter is directly fixed with and hung down from the horizontal plane. Further, the horizontal fixing plane is provided at an outer surface of the crankcase and moreover under a cam fixing portion provided in the crankcase. The oil filter is disposed in a space which is formed by the horizontal fixing plane and a lower vertical side surface of the crankcase.

Abstract: In a lubricant dosing arrangement for the lubrication of valve shafts on the cylinder heads of piston engine wherein the valve shafts are axially movably supported in housing bores formed in the cylinder heads and the housing bores include spaced lubricant seals so as to form between the seals around the valve shaft lubricant reservoirs, means are provided for supplying lubricant to the lubricant reservoirs and the valves shafts include means for permitting passage of lubricant out of the reservoir at a rate depending on the lift movement of the valve shafts so as to dose the lubricant volume permitted to flow out of the lubricant reservoir for the lubrication of the valve shaft.

Abstract: The present invention relates to a small four-stroke gasoline engine with oil mist lubrication. The lubrication oil way of the engine includes a crankshaft chamber B, a camshaft chamber C, an upper rocker arm chamber D and a condensation chamber E. The camshaft chamber C communicates with the upper rocker arm chamber D via a tappet cavity 13. The upper rocker arm chamber D communicates with the condensation chamber E. An oil mist chamber A is surrounded by an upper case body 3 and a lower case body 4 at the side of the crankshaft chamber B, the bottom of the oil mist chamber A communicates with the crankshaft chamber B. An oilsplash impeller 2 is fixed on a crankshaft, which extends into the oil mist chamber A. An oil way 12 is provided on the upper case body 3 between the oil mist chamber A and the camshaft chamber C. An oil return way 15 is provided on a cylinder head assembly 5. An oil return way 14 is provided on the upper case body 3.

Abstract: The invention relates to a dry sump type or semidry sump type lubricating system of an engine in which a lubricating method executes an operation while keeping an inner side of a crank chamber in a dry state. An oil drain port is formed in a bottom surface of each of individual crank chambers partitioned into the cylinders, and a scavenging oil pump is provided so as to suck out oil to an oil reservoir portion which is isolated from each of the individual crank chambers. An oil collecting chamber communicating with a suction portion of the scavenging oil pump is provided in a lower side of the bottom wall in the crank chamber, and the oil drain port is communicated with the oil collecting chamber.

Abstract: An oil pump for an engine having a first cam shaft and a second cam shaft. The oil pump includes a housing and a first pump assembly at least partially disposed within the housing. The first pump assembly includes a rotating element that is adapted to be directly driven by the first cam shaft. A second pump assembly is at least partially disposed within the housing. The second pump assembly includes a rotating element that is adapted to be directly driven by the second cam shaft.

Abstract: A crankcase lubricating system and method for lubricating an engine of a motor vehicle. The crankcase lubricating system includes filterless lubricant circulation system, and a crankcase lubricant containing a fully formulated lubricating base oil meeting or exceeding ILSAC GF-4 or API CI-4 minimum performance standards for engine oils.

Abstract: A sub-gallery for leading oil to a cylinder head side of an engine is provided in a crankcase in such a manner as to be connected to an outlet of an oil filter and in parallel with a main gallery. A lubricating device is also provided to equally feed oil to each of portions to be lubricated in the engine, including the main gallery connected to a discharge port of an oil pump via the oil filter. This lubricating device sufficiently feeds oil to even the cylinder head side of the engine while avoiding increased pressure loss of the oil.

Abstract: A lubricating structure of an engine for vehicle comprising a main pump for pressure-feeding a lubricating oil, and a scavenging pump for pumping the lubricating oil out of a crank room to transfer the oil, can reduce an applied load of a main pump and reduce a power loss of the pump while reducing the size of the main pump and the scavenging pump, and thus reducing the size of the entire engine. In the lubricating structure, the crank room and a transmission room are divided by a partition, an oil storage room communicating with a discharging portion of the scavenging pump is formed, and an oil passage for lubricating a transmission is formed in the transmission shaft along the shaft center and is opened to the oil storage room. The lubricating oil in the oil storage room is supplied to lubrication points on the transmission shaft through the oil passage of the transmission shaft.

Abstract: Method and arrangement for providing a lubrication system for an internal combustion engine with at least one piston reciprocating in an engine cylinder. The lubrication system includes an oil pump (11) with adjustable feed pressure which is controlled via a pressure-sensing means (18) which is acted on by the working pressure of the oil. The pressure-sensing means (18) is acted on via a pressure outlet (21) which is hydraulically connected to one of the bearings of the internal combustion engine which are lubricated by the lubrication system.

Abstract: An engine crankshaft includes a split crankshaft journal that includes offset connecting rod journals for two connecting rods. Oil supply systems disposed on opposite axial sides of the crankshaft journal each lubricate a corresponding one of the connecting rod journals. The oil supply systems are either axial or peripheral oil supply systems that do not require oil to be supplied to the crankshaft through the main crankcase bearings. Consequently, the oil supply systems sufficiently lubricate each connecting rod journal without requiring weakening holes or grooves in the main crankcase bearings.

Abstract: A hermetic electric compressor is capable of efficiently pumping up a necessary amount of lubricating oil even at low-speed rotation and has a simple constitution to provide an excellent workablity in assembling. The hermetic electric compressor includes an oil pump. The oil pump includes (i) a slanting channel formed in the lower portion of a main shaft and slanting from the lower portion to the upper portion thereof outwardly, (ii) a throttle formed at the bottom end of the main shaft and having an inlet port of diameter smaller than the section of the slanting channel at the center thereof, and (iii) a lower communicating passage for providing a communication between the bottom end of a spiral groove and the slanting channel. This constitution is capable of effectively lift the head of the lubricating oil.

Abstract: A four-stroke internal combustion engine is provided that is capable of use in many power tools, including those power tools subjected to tippable applications. The engine includes an oil reservoir and a crank chamber separated by a divider. The divider includes a slot that allows lubricant to move from the oil reservoir into the crank chamber and from the crank chamber into the oil reservoir in response to pressure fluctuations of the engine. The engine can include an insert positioned within the slot to at least partially restrict the slot thereby modifying the lubricant communication between the crank chamber and the oil reservoir through the slot. The insert can be wedge-shaped and at least partially define a passage such that when the insert is positioned within the slot the transfer of lubricant between the crank chamber and the oil reservoir occurs through the passage.

Abstract: The oil pan includes an oil introducing portion that has an oil introducing plate. The oil introducing plate has an insertion hole for receiving a sucking portion of an oil strainer. The oil introducing plate extends from the periphery of the insertion hole toward a side wall of the oil pan. The oil returned from the first oil return passage is introduced to flow along the oil introducing plate via an oil falling hole formed in a baffle plate that is positioned at the bottom of a crank case of the internal combustion engine. The oil introducing portion further includes a plurality of inclined wall portions mounted on a bottom portion of the oil pan in the vicinity of the side wall of the oil pan in order to support the oil introducing plate. Opening portions are formed between the inclined wall portions and the bottom portion of the oil pan. The oil introducing plate of the oil introducing portion is located just below the oil falling hole formed in said baffle plate.

Abstract: An improved lubrication structure is provided in an engine by optimizing the structure for recovering scooped oil for enhanced oil recovery efficiency. The oil, which has been scooped up and scattered by the rotation of a clutch, is captured within a concave groove provided within a cylindrical inner surface of a case cover facing the clutch. The captured oil is smoothly guided from the concave groove to an oil receiver of a crankcase via a bent upper edge part of an oil guide plate. The recovered oil passes through dropping holes of a recovered oil path and is supplied to a gear engagement part of a transmission system located below the recovered oil path.

Abstract: A lubricating system for a power unit for a vehicle with an internal combustion engine. A static oil hydraulic type non-stage transmission is disposed on a left lateral side of a crankshaft, and a lubricating oil tank is formed integrally with a main body of the internal combustion engine and is disposed on a right lateral side opposite to the side of the transmission, with the crankshaft therebetween.

Abstract: A lubricating structure for engines, wherein an oil feed pump and an oil recovery pump are disposed so as to avoid interference between the oil feed and recovery pumps and a clutch mechanism and an increase in the size of the engine. The clutch mechanism 38 is disposed at a location toward a left end of a crankshaft 7 as an output shaft 7a, which is rotatably supported between an upper crankcase 5 and a lower crankcase 6, that is, disposed on a left side of an engine room. A magnet cover 60 is fixed to right side parts of the two crankcases 5, 6. A magnet MG is disposed between the two crankcases 5, 6 and the magnet cover 60 at a location toward a right end 7b of the crankshaft 7. An oil pump FEP for feeding lubricating oil is disposed between the two crankcases 5, 6 and the magnet cover 60, and an oil pump SCP for recovering lubricating oil is disposed between the two crankcases 5, 6 and the magnet cover 60.

Abstract: An internal combustion engine having an oil drainback passage and integral check valve. The oil drainback passage allows the flow of oil from the valve box to the crankcase of the engine during normal operation and prevents the backwards flow of oil from the crankcase to the valve box when high pressures exist in the crankcase or if the engine is operated at elevated angles. The oil drainback passage is formed by a bore through a cylinder wall of the crankcase and a bore through the cylinder head. The check valve includes a cavity within the cylinder wall of the crankcase, located at the end of the bore in the cylinder wall where it meets the bore in the cylinder head, and a check ball disposed within the cavity. During normal operation, the check ball floats within the cavity and allows the flow of oil through the oil drainback passage back to the crankcase.

Abstract: A lubrication structure for splash lubrication in an engine includes an oil collector formed as a depression in the outer peripheral surface of the crank pin and an oil groove provided on the big-end of the connecting rod. The oil collector is formed approximately at the center, in an axial direction, of the crank pin. The position of the oil collector is chosen so as to be displaced from an explosive force in an expansion cycle of the engine. The oil groove is provided on the big-end of the connecting rod, and has a first end and a second end. The first end is open in the inner peripheral surface at the center thereof in an axial direction, and the second end is open into the crank case. The oil collector receives oil stored in the crank case and the oil is transferred to the oil groove.

Abstract: A baffle plate is arranged between a crankshaft axially supported in a freely rotating manner by a cylinder block and a bearing cap and an oil pan storing lubricating oil supplied to each part of a vehicle engine. The baffle plate is fastened to the bearing cap using parent bolts for fastening the bearing cap and the cylinder block through screwing from the bottom surface of the bearing cap.

Abstract: There is provided a lubricating device for a motorcycle combustion engine, which allows the motorcycle to exhibit a desired banking angle and also to have a lower center of gravity. The lubricating device is designed to supply a lubricant oil to an in-line multicylinder combustion engine (E) mounted on a motorcycle frame structure (FR) and having a crankcase (CR) and includes a main gallery (21) formed in a lower portion of the crankcase (CR) and journal oiling passages (25) branched off from the main gallery (21) for supplying the lubricant oil towards crank journals (23b) of a crankshaft (23) of the engine. The main gallery (21) has opposite end portions (21a, 21a) inclined to extend outwardly upwardly.

Abstract: An internal combustion engine has a plurality of cylinders containing pistons connected with a crankshaft for transmitting power. The cylinders have closed ends, intake and exhaust ports communicating with the cylinders through the closed ends, valves operable to open and close the ports to air and exhaust flow to and from the cylinders, and a lower end pressure oil lubrication system operative to lubricate at least the cylinders, pistons and crankshaft of the engine. The engine includes hydraulic actuators operable to actuate the valves and forming part of a separate upper end hydraulic oil actuation system operative to selectively supply high pressure hydraulic oil to the hydraulic actuators to actuate the valves in a predetermined manner. Optionally, the hydraulic system may have an oil reservoir within the engine block, such as in the valley between the cylinder banks of a V type engine.

Abstract: To provide a lubricating device for an engine in which a generator is housed in a generator chamber formed between a crankcase and a generator cover connected to the crankcase. A block side return oil passage is in communication with a head side return oil passage provided in a cylinder head and is provided in a cylinder block in such a manner as to be in communication with the generator chamber in order to return oil from the cylinder head to the oil pan through the generator chamber. The device is intended to prevent a raise in oil temperature and an increase in friction loss by adjusting the amount of oil flowing into the generator chamber to an optimum value. A branch oil passage is in communication with an intermediate portion of a block side return oil passage and is provided in a cylinder block. The branch oil passage is formed so as to allow part of the oil flowing in the block side return oil passage to bypass the generator chamber and to flow to the oil pan.

Abstract: An internal combustion engine includes a hydraulic system with a hydraulic pump. A lubricant system for moving parts of the engine is also provided, which includes a lubricant pump. To enable making the engine smaller, it is proposed that the hydraulic pump is connected to the lubricant system in such a way that it can be lubricated by the lubricant.

Abstract: An oil pressure control apparatus which includes a source of hydraulic pressure introducing the hydraulic pressure to a hydraulic actuator which is actuated by hydraulic pressure, a fluid passage which is connected between the source of hydraulic pressure and the hydraulic actuator for introducing and discharging hydraulic pressure from the source of hydraulic pressure to the actuator, a control valve which is disposed in the fluid passages for controlling the hydraulic pressure and a filter is disposed in a position that is between the actuator and the control valve. Thereby, the control valve is capable to be operated smoothly.

Abstract: An oil feed pump for feeding oil in an oil tank to an engine, an oil recovery pump for feeding oil in a crankcase into the oil tank, an oil drain pipe connected to the lower portion of the crankcase and extending upward, and an opening provided on top of the oil tank are provided in a lubrication system. An opening of the oil drain pipe opens at the position upward of the oil level in the crankcase at a moment when the oil in the oil tank is returned into the crankcase. A cap is provided with a dip stick. The engine can be mounted on a small planing boat with the crankshaft oriented in the fore-and-aft direction. The oil tank is integrally formed with the front portion of the engine so as to be elongated in the vertical direction and is formed with the opening on top.

Abstract: The interior of a crankcase is divided into a front crank chamber and a rear transmission chamber by a partition wall of a given height. A lower part of the transmission case is used as an oil reservoir chamber for reserving lubricating oil. Opposite ends of the crankcase are covered with covers to form a generator chamber and a clutch chamber. The crank chamber is connected to the generator chamber by a drain passage to drain oil collected in the crank chamber into the generator chamber. A scavenging pump placed in the clutch chamber sucks the oil collected in the generator chamber through an oil passage extending across the crankcase under the crank chamber and discharges the oil into an air space in the clutch chamber.

Abstract: The invention pertains to an internal combustion engine with a crankcase, a crankshaft and a camshaft for controlling at least one intake and exhaust valve, as well as an oil pump for delivering lubricating oil to the crankshaft. Downstream on the outlet side of the oil pump is an oil pressure regulating valve for limiting the oil pressure. The valve gate, which is contacted by a spring element in the closing direction, depending on the amount of oil delivered and/or the oil temperature, the valve gate frees an opening that can be connected with the inlet side of the oil pump. It is suggested that the camshaft be seated in longitudinally displaceable fashion within the crankcase and form the valve gate of the oil pressure control valve. An oil pressure-limiting valve for an internal combustion engine is thus implemented in a simple way.

Abstract: The invention relates to a cover plate (2) for a crankcase (1) of an internal combustion engine. Said cover plate (2) extends over the entire surface area of the crankcase (1). The auxiliary aggregates (6, 7) and filters are mounted on the cover plate (2). In addition, the cover plate (2) comprises channels for guiding media. The invention is advantageous in that it facilitates mounting.

Abstract: A power system includes an engine having a first lubrication circuit and at least one auxiliary power unit having a second lubrication circuit. The first lubrication circuit is in fluid communication with the second lubrication circuit.

Abstract: A lubrication system for a crankshaft, which is capable of improving the durability of the crankshaft, is provided. The crankshaft is rotatably mounted in a crankcase and is connected to a piston via a connecting rod. The crankshaft has a journal portion and a crank web integrally provided therewith, wherein a crankpin is provided on the crank web. A lubricating oil-supply path is formed in the crankshaft, and an opening of the lubricating-oil supply path is formed on an end face of the crank web so as to face to an end portion of a bearing. The lubricating oil discharged from the opening is supplied to the bearing through an end portion of the bearing, and the opening for discharging the lubricating oil is not formed on an outside periphery of the crankpin. Therefore, the outside periphery becomes wholly flat.

Abstract: An oil jet device for piston cooling in which no press-fitting device is required, and the O-ring is prevented from being broken. A filter plug is inserted into an oil passage opening from the crank journal of a crankcase toward the side of the lower portion of the cylinder, and the crank journal is sealed by a plain bearing being abutted against the filter plug. The oil passage is formed by ring-shaped feed paths formed in the ring-shape on the bearing portions on the plain bearing and the crankcase.

Abstract: A method to employ instrumentation to effectuate variation in lubricant flow rate or properties in response to actual engine conditions. Preferably, the present invention provides a method for the in situ monitoring of the lubricating oil's effectiveness in a two-stroke diesel engine by measuring the used lubricant's Fe content and fuel sulfur content with XRF technology and the used lubricant's BN with an IR measurement device, and for efficiently modifying the lubricant's properties and/or flow rate to the equipment in response to the actual wear or corrosion needs of the machinery or engine.

Abstract: An engine crankcase and transmission assembly includes a transmission housing including a forward mounting portion and a crankcase including a rear-mounting portion configured for mounting to the transmission. The rear-mounting portion of the crankcase includes an upper section and a lower section spaced apart from the upper section so that the first transmission housing and the crankcase define a passage there between when mounted. An oil sump at a lower portion of the crankcase including an expanded section with an outer surface extending rearward beyond the rear mounting portion of the crankcase. An adapter provides for mounting to a second transmission housing. The crankcase receives interchangeable first and second oil routing devices with oil line fittings for receiving complementary oil lines.

Abstract: A lubricating system for a power unit for a vehicle with an internal combustion engine. A static oil hydraulic type non-stage transmission is disposed on a left lateral side of a crankshaft, and a lubricating oil tank is formed integrally with a main body of the internal combustion engine and is disposed on a right lateral side opposite to the side of the transmission, with the crankshaft therebetween.

Abstract: A lubricating system for an internal combustion engine includes a recovery pump by which a lubricating oil dropping to and dwelling in a bottom portion of a crankcase after lubricating individual portions of the internal combustion engine is sucked through a pump suction port opened in the bottom portion of the crankcase and is fed to a lubricating oil tank. A supply pump is provided for supplying the lubricating oil from the oil tank to the individual portions of the internal combustion engine. The lubricating tank is integral with the crankcase and is partitioned from a crank chamber by a partition wall projecting from the inside wall of the crankcase. The lubricating system includes an overflow oil passage through which the lubricating oil that flows over the upper edge of a partition wall of the lubricating tank is led to a suction port of the recovery pump.

Abstract: A lubricating oil supply system is provided for the connecting rod bearings of a crankshaft of a multi-cylinder internal-combustion engine. Oil ducts extend from the bearing journals to the crank pins of the crankshaft, the oil supply taking place by way of the main bearings of the crankshaft in that the oil ducts extend from one main bearing or bearing journal respectively to the crank pins or connecting rod bearings in each case adjoining on both sides. In the respective bearing journals of the crankshaft for the lubricating oil supply to the connecting rod bearings adjoining on the left and right respectively, two oil bores respectively are provided which extend at an angle and, converging to an oil bore, extend to the two adjoining crank pins. The two oil bores interact with oil supply grooves provided in the main bearings for the lubricating oil supply.

Abstract: A sub-gallery for leading oil to a cylinder head side of an engine is provided in a crankcase in such a manner as to be connected to an outlet of an oil filter and in parallel with a main gallery. A lubricating device is also provided to equally feed oil to each of portions to be lubricated in the engine, including the main gallery connected to a discharge port of an oil pump via the oil filter. This lubricating device sufficiently feeds oil to even the cylinder head side of the engine while avoiding increased pressure loss of the oil.

Abstract: A lubricating system for an internal combustion engine includes lubricating oil recovery oil passages through which lubricating oil dropping to and dwelling in a bottom portion of a crankcase after lubricating individual portions of an internal combustion engine is fed to a lubricating oil tank through an oil cooler by a recovery pump. Lubricating oil supply oil passages supply the lubricating oil from the lubricating oil tank to the individual portions of the internal combustion engine needing lubrication and cooling through an oil filter by a supply pump. The lubricating system includes a branch passage branched from the lubricating oil recovery oil passage communicating from the oil cooler to the lubricating oil tank. The branch passage supplies the lubricating oil to at least one of the individual portions of the internal combustion engine.

Abstract: In a preferred embodiment, a windage tray assembly is mounted to crankshaft bearing caps which connect with oil passages in the windage tray. The passages carry the oil through nozzles directed toward the interior of associated pistons. The arrangement utilizes the windage tray and bearing caps as carriers for piston cooling oil obtained from the bearing caps, which are already supplied with oil for lubricating the bearings. Thus, modifications of an engine design to install a piston cooling system are limited to redesign of the windage tray to a sandwich-like assembly and modification of the bearing caps to conduct oil from the bearings to the windage tray passages. To limit oil pumping energy, oil distribution holes in the bearing caps connect intermittently with crankshaft journal feed passages so the oil is distributed in individually timed streams or sprays directed toward the pistons for a short interval once every revolution of the engine crankshaft.

Abstract: A balancer shaft apparatus efficiently prevent oil from being stirred in the oil pan and from being splashed into the cylinder block during the balancer-shaft rotation. Oil in a housing of the balancer shaft is discharged from a drainage hole formed at such a location above an oil level as to contact a base serving as a bearing beam of a crankshaft supporting member. The discharged oil hits inner surfaces of a recess formed on the lower portion of the crankshaft supporting member to form oil drops, returning to an oil pan. The housing is provided with guide passages connecting the drainage holes to a space in which the balancer shaft is disposed for draining the oil. These guide passages are formed with tapered guide surfaces for orienting the oil towards the lower portions of the crankshaft supporting member while splashed oil caused by the balancer-shaft rotation is drained through the drainage holes.

Abstract: A pump assembly for mounting a high-pressure oil pump on an internal combustion engine where the pump in the assembly is mounted in a closed chamber and a solenoid controlled valve is mounted outside of the chamber.

Abstract: An improved lubrication arrangement for an internal combustion engine of the push tube (59) type. A carrier structure (43) is fixed relative to an upper surface of the cylinder head (31) and includes a fixed fulcrum location (49) for each rocker arm (51). The carrier structure (43) defines a lubrication passage (67,69) providing lubrication fluid to the fixed fulcrum location (49). The engine block (11) and the cylinder head (31) cooperate to define a fluid chamber (81) surrounding the push tube (59). Lubrication fluid flows out adjacent the fixed fulcrum location (49) and flows under the influence of gravity into the fluid chamber (81). The push tube defines a plurality of openings (83) whereby lubrication fluid flows from the fluid chamber (81) into the interior (85) of the push tube.

Abstract: An engine has a lubrication system that lubricates the engine with lubricant. The lubrication system incorporates a lubrication pump that periodically pressurizes the lubricant toward the engine. An engine speed sensor and a throttle valve position sensor are provided to sense an engine speed and a throttle valve position (i.e., engine load), respectively. A control device controls the lubrication pump. The control device determines a frequency of the periodic pressurization based upon signals from the sensors. The control device sets a pressurizing time of the lubrication pump to a period of time shorter than the maximum period of time that can be set for the lubrication pump at the determined frequency, when the signals from the sensors indicate that the engine speed is less than a preset engine speed and the engine load is less than a preset engine load.

Abstract: A hollow camshaft (19) lubrication system for aircraft engines that supplies lubricant (14) to cam lobe surfaces (25) from the interior surface (22) of the hollow camshaft (19) even during periods when aircraft operation moves the rotation axis of the hollow camshaft (19) from horizontal.

Abstract: An oil passage extending from an oil pump to a discharge port in an internal combustion engine is, at its halfway point, branched into at least two oil passages, for example, a first oil passage and a second oil passage. One of the at least two branched oil passages, for example, the second oil passage is provided with a restricting portion configured as a first orifice for restricting a flow amount of oil by reducing a diameter of the first orifice. A bypass valve is provided which acts, when a hydraulic pressure in the second oil passage exceeds a specific value, to bypass the first orifice so as to increase the flow rate of oil. It is possible to increase the hydraulic pressure at the time of low speed rotation up to a necessary pressure only by providing the restricting portion, without enhancing the performance of the oil pump.

Abstract: An oil pump is formed by a main body portion, a base, and a pump cover, and is provided with a rotor rotational shaft. The oil pump is formed with a main pump and a sub pump. The oil pump is attached to bond with a wall face of a thick-walled portion of a crankcase. A relief valve chamber is provided in the thick-walled portion in parallel with the rotor rotational shaft. A relief valve is contained therein in parallel with the rotor rotational shaft. A surrounding space in the relief valve chamber is directly connected to a pumping portion of the oil pump. This combination of elements and configuration provides for an oil pump that operates with efficiency, and that is small in size, light in weight.

Abstract: An oil feed pump for feeding oil in an oil tank to an engine, an oil recovery pump for feeding oil in a crankcase into the oil tank, an oil drain pipe connected to the lower portion of the crankcase and extending upward, and an opening provided on top of the oil tank are provided in a lubrication system. An opening of the oil drain pipe opens at the position upward of the oil level in the crankcase at a moment when the oil in the oil tank is returned into the crankcase. A cap is provided with a dip stick. The engine can be mounted on a small planing boat with the crankshaft oriented in the fore-and-aft direction. The oil tank is integrally formed with the front portion of the engine so as to be elongated in the vertical direction and is formed with the opening on top. The aforementioned lubrication system enables oil changes to be performed easily.

Abstract: A motorcycle lubrication oil cooling system that cools lubrication oil without increasing the number of parts, weight, or cost, and yet is simple in construction. The cooling system is applicable to motorcycles in which an engine is cooled by a coolant pump driven by a crankshaft. The coolant pump is provided on a side face of the engine, and an oil storage chamber capable of storing a specified amount of lubrication oil is provided adjacent to the coolant pump, while a covering member is provided to cover both the oil storage chamber and a coolant pump chamber that houses the coolant pump. This abstract is neither intended to define the invention discloses in this specification nor intended to limit the scope of the invention in any way.

Abstract: The invention relates to a method and apparatus for returning the oil drained from a working pressure space of a hydraulic motor into a motor casing to an oil line, which is connected to the motor and which is in communication via a divider with intra-motor flow channels which are in communication with the working pressure spaces. The oil seeping into the casing is conveyed by means of pressure variations internal of the hydraulic motor, pulsating consistently with rotating motion, into the oil line presently at a lower pressure and connected to the motor by way of said divider. Therefor, the casing space is connected by a return conduit through a one-way valve to at least one flow channel, which lies between the divider of the motor and the working pressure space of the motor.