Abstract: An oil-cooled engine assembly is provided for cooling lubricating oil, which has lubricated movable parts of an engine and subsequently recirculating cooled lubricating oil to the movable parts. The engine assembly includes a lubricating oil pump contained in the engine, and a hollow frame body which supports the engine. The hollow frame body has an oil passage through which lubricating oil flows. The lubricating oil pump is connected to the oil passage. Lubricating oil, which has lubricated the movable parts of the engine is air cooled with the frame body. Cooled lubricating oil is circulated again to the movable parts of the engine.

Abstract: Formed in a cylinder block of a multi-cylinder engine are oil grooves each arranged in a top deck of the cylinder block to surround a corresponding cylinder liner, a supply channel connected to an oil pump, a return channel connected to an oil pan, communication holes interconnecting adjacent oil grooves in series, an inflow hole connecting the most upstream oil groove to the supply channel and an outflow hole connecting the most downstream oil groove to the return channel. Consequently, the oil grooves of all cylinders connected in series cause engine oil to flow through all the oil grooves at the same rate. Such an arrangement is simple in structure and has reduced the number of components so that the manufacturing cost is reduced and the reliability of the cooling system is enhanced.

Abstract: An oil-cooled engine assembly is provided for cooling lubricating oil, which has lubricated movable parts of an engine and subsequently recirculating cooled lubricating oil to the movable parts. The engine assembly includes a lubricating oil pump contained in the engine, and a hollow frame body which supports the engine. The hollow frame body has an oil passage through which lubricating oil flows. The lubricating oil pump is connected to the oil passage. Lubricating oil, which has lubricated the movable parts of the engine is air cooled with the frame body. Cooled lubricating oil is circulated again to the movable parts of the engine.

Abstract: Formed in a cylinder block are oil grooves each arranged in a top deck of the cylinder block to surround a corresponding cylinder liner, a supply channel connected to an oil pump, a return channel connected to an oil pan, communication holes interconnecting adjacent oil grooves in series, an inflow hole connecting the most upstream oil groove to the supply channel and an outflow hole connecting the most downstream oil groove to the return channel. Consequently, the oil grooves of all cylinders connected in series cause engine oil to flow through all the oil grooves at the same rate. Such an arrangement is simple in structure and has reduced the number of components so that the manufacturing cost is reduced and the reliability of the cooling system is enhanced.

Abstract: A cooling system for an internal combustion engine includes a first circuit for cooling the cylinder head and a second circuit for cooling the engine block which are completely separated from each other and make use of a first fluid and a second fluid which are never mixed with each other. The flow of the first fluid circulating in the circuit for cooling the cylinder head is used, totally or partially, for cooling the second fluid which cools the engine block in a heat exchanger. Preferably, the second cooling fluid is the engine lubricating oil.

Abstract: In a heat transfer system (10), an upper coolant chamber (31) and a lower coolant chamber (24) of a typical engine, such as an internal combustion engine, fuel cell, boiler, or other engine for converting fuel to thermal energy, are formed adjacent to the heat-rejecting components of the engine and are hermetically sealed to prevent exposure of heat-transfer liquid within the chambers to the engine's ambient atmosphere. The heat-transfer liquid is preferably a substantially anhydrous, boilable liquid having a saturation temperature higher than that of water, and the heat-transfer liquid is pumped at a predetermined flow rate, and distributed through the heat-transfer fluid chamber so that the liquid within the chambers substantially condenses the heat-transfer liquid vaporized by the heat-rejecting components of the engine.