A four-cycle multi-cylinder engine includes a crankcase, a cylinder block, a crankshaft, and a gear-shift input shaft. The crankcase is vertically divided into an upper case and a lower case. The cylinder block is integrated with the crankcase. The crankshaft and the gear-shift input shaft are journaled to a contact surface of the crankcase. The cylinder block is inclined rearward such that an extended line intersects with a cylinder axis line of the cylinder block at an acute angle in an engine side view. The extended line connects respective central axes of the crankshaft and the gear-shift input shaft.

An engine assembly includes an air-cooled engine and an external oil reservoir. The engine includes a vertically-oriented crankshaft a crankcase cover having a front portion and a rear portion, wherein the front portion of the crankcase cover and the cylinder head are located forward of a vertical plane that includes the crankshaft axis, a return pump housing formed in the exterior of the crankcase cover, a return pump positioned in the return pump housing, and a return pump inlet formed through the crankcase cover, wherein the return pump inlet is located in the front portion of the crankcase cover and the return pump inlet is located closer to the camshaft than to the crankshaft. The external oil reservoir includes an oil tank and an oil filter assembly.

An internal combustion engine oil utilization system, comprising one or more oil pumps to receive and discharge engine oil including an engine oil circulation loop comprising a first flow path and a second flow path. The first flow path receives at least a portion of the oil discharged from the one or more oil pumps and utilizes the oil to lubricate the engine during running operation of the engine. The second flow path receives at least a portion of the oil discharged from the one or more oil pumps and accumulates the oil to start the engine and/or to lubricate the engine during at least one of a pre-starting operation and a starting operation of the engine.

An engine assembly includes an engine, an external oil reservoir, a supply pump, and a return pump. The engine includes an oil gallery configured to distribute oil and a crankcase chamber. The external oil reservoir includes an oil tank defining an oil chamber and an oil filter assembly including a housing at least partially defining a filter chamber, and a filter positioned within the filter chamber. The supply pump is in fluid communication with the oil chamber and the oil gallery and the supply pump is configured to draw oil from the oil chamber and provide pressurized oil to the oil gallery. The return pump in fluid communication with the crankcase chamber and the filter chamber and the return pump is configured to draw oil from the crankcase chamber and provide pressurized oil to the filter chamber.

The present disclosure provides a lubrication system comprising: a pump having an inlet in fluid communication with a lubricant source and an outlet; a cooler having an inlet in fluid communication with the outlet of the pump and an outlet; a lubrication filter having an inlet in fluid communication with the outlet of the cooler and an outlet; a first delivery path in fluid communication with the outlet of the lubrication filter, the first delivery path being configured to deliver cooled, filtered lubricant to a bearing system of an engine; and a second delivery path in fluid communication with the outlet of the pump, the second delivery path being configured to deliver uncooled, unfiltered lubricant to piston cooling nozzles of the engine.

The present disclosure provides a lubrication system comprising: a pump having an inlet in fluid communication with a lubricant source and an outlet; a cooler having an inlet in fluid communication with the outlet of the pump and an outlet; a lubrication filter having an inlet in fluid communication with the outlet of the cooler and an outlet; a first delivery path in fluid communication with the outlet of the lubrication filter, the first delivery path being configured to deliver cooled, filtered lubricant to a bearing system of an engine; and a second delivery path in fluid communication with the outlet of the pump, the second delivery path being configured to deliver uncooled, unfiltered lubricant to piston cooling nozzles of the engine.

A hydraulic system of a transmission having a controller and a variable displacement pump. The pump includes an inlet and outlet and is adapted to be driven by a torque-generating mechanism. The system also includes a lube circuit fluidly coupled to the pump. A lube regulator valve is disposed in the lube circuit, such that the lube regulator valve is configured to move between at least a regulated position and an unregulated position. The regulated position corresponds to a regulated pressure in the lube circuit. A pressure switch is fluidly coupled to the lube regulator valve and configured to move between a first position and a second position, where the switch is disposed in electrical communication with the controller. A solenoid is disposed in electrical communication with the controller and is controllably coupled to the pump to alter the displacement of the pump.

A hydraulic system of a transmission having a controller and a variable displacement pump. The pump includes an inlet and outlet and is adapted to be driven by a torque-generating mechanism. The system also includes a lube circuit fluidly coupled to the pump. A lube regulator valve is disposed in the lube circuit, such that the lube regulator valve is configured to move between at least a regulated position and an unregulated position. The regulated position corresponds to a regulated pressure in the lube circuit. A pressure switch is fluidly coupled to the lube regulator valve and configured to move between a first position and a second position, where the switch is disposed in electrical communication with the controller. A solenoid is disposed in electrical communication with the controller and is controllably coupled to the pump to alter the displacement of the pump.

A hydraulic system of a transmission having a controller and a variable displacement pump. The pump includes an inlet and outlet and is adapted to be driven by a torque-generating mechanism. The system also includes a lube circuit fluidly coupled to the pump. A lube regulator valve is disposed in the lube circuit, such that the lube regulator valve is configured to move between at least a regulated position and an unregulated position. The regulated position corresponds to a regulated pressure in the lube circuit. A pressure switch is fluidly coupled to the lube regulator valve and configured to move between a first position and a second position, where the switch is disposed in electrical communication with the controller. A solenoid is disposed in electrical communication with the controller and is controllably coupled to the pump to alter the displacement of the pump.

A hydraulic system of a transmission having a controller and a variable displacement pump. The pump includes an inlet and outlet and is adapted to be driven by a torque-generating mechanism. The system also includes a lube circuit fluidly coupled to the pump. A lube regulator valve is disposed in the lube circuit, such that the lube regulator valve is configured to move between at least a regulated position and an unregulated position. The regulated position corresponds to a regulated pressure in the lube circuit. A pressure switch is fluidly coupled to the lube regulator valve and configured to move between a first position and a second position, where the switch is disposed in electrical communication with the controller. A solenoid is disposed in electrical communication with the controller and is controllably coupled to the pump to alter the displacement of the pump.