Abstract: This disclosure describes, in part, systems and structures for an exhaust assembly that includes an exhaust tube and a coolant passage. The exhaust tube is oriented about an axis and an exhaust gas is configured to flow through the exhaust tube in a direction away from an end of the exhaust tube. The coolant passage is oriented about the axis radially outward of the exhaust tube, the coolant passage having an inner shell and an outer shell. The heat capacity of the volume of the coolant contained within the coolant passage is above a threshold ratio of a heat capacitance of a radiation shield, exhaust tube, and inner shell of the coolant passage to prevent coolant boiling after shutdown.

Abstract: An engine includes a cylinder block including a first jacket through which a coolant flows, a spacer disposed within the first jacket, a cylinder head including a second jacket through which the coolant flows from the first jacket; and a gasket interposed between the cylinder block and the cylinder head. The cylinder block includes a branch passage branched off from the first jacket to supply the coolant to an external device. The gasket includes communication ports that communicate the first jacket with the second jacket. The spacer includes a protruding portion that penetrates one of the communication ports that is closest to the branch passage. There is a clearance between the protruding portion and the one of the communication ports.

Abstract: A boat propulsion machine includes a power source, a drive shaft, a propeller, a gear mechanism, a gear case, a tank configured to store a cooling liquid for cooling the power source, a heat sink configured to cool the cooling liquid, a cooling liquid passage connecting the power source and the heat sink, and a pump a pump configured to pump the cooling liquid to circulate through the cooling liquid passage. The power source, the tank, and the pump are provided at an upper portion of the boat propulsion machine. The gear case is provided at a lower portion of the boat propulsion machine. The drive shaft extends in an upper-lower direction between the power source and the gear mechanism. The heat sink is provided at a position lower than the power source and higher than the gear case in the boat propulsion machine.

Abstract: Methods and systems are provided for a cooling arrangement. In one example, a system comprises a separator arranged in a block coolant jacket. The separator fluidly separates an upper portion of the block coolant jacket from a lower portion of the block coolant jacket.

Abstract: Methods for depositing protective coatings on aerospace components are provided and include sequentially exposing the aerospace component to a chromium precursor and a reactant to form a chromium-containing layer on a surface of the aerospace component by an atomic layer deposition process. The chromium-containing layer contains metallic chromium, chromium oxide, chromium nitride, chromium carbide, chromium silicide, or any combination thereof.

Abstract: An article comprises a body and a conformal protective layer on at least one surface of the body. The conformal protective layer is a plasma resistant rare earth oxide film having a thickness of less than 1000 ?m, wherein the plasma resistant rare earth oxide film consists essentially of 40 mol % to less than 100 mol % of Y2O3, over 0 mol % to 60 mol % of ZrO2, and 0 mol % to 9 mol % of Al2O3.

Abstract: An article comprises a body and a conformal protective layer on at least one surface of the body. The conformal protective layer is a plasma resistant rare earth oxide film having a thickness of less than 1000 ?m, wherein the plasma resistant rare earth oxide film is selected from a group consisting of an Er—Y composition, an Er—Al—Y composition, an Er—Y—Zr composition, and an Er—Al composition.

Abstract: An article comprises a body and a conformal protective layer on at least one surface of the body. The conformal protective layer is a plasma resistant rare earth oxide film having a thickness of less than 1000 ?m, wherein the plasma resistant rare earth oxide is selected from a group consisting of YF3, Er4Al2O9, ErAlO3, and a ceramic compound comprising Y4Al2O9 and a solid-solution of Y2O3—ZrO2.

Abstract: An engine block includes one or more cylinder bores at least partially surrounded by a cylinder bore wall. The cylinder bore wall includes a liner stop mechanism to support a liner in the cylinder bore. The engine block has an outer cylinder block wall that is exterior to the cylinder bore wall. The outer cylinder block wall includes at least one rib located relative to the liner stop mechanism to reduce rotation and buckling of the liner during operation of the engine.

Abstract: A combustion engine housing with cylinder cooling includes at least one cylinder. The cylinder cooling channel has a distribution cross-sectional area having a cross-sectional area through which coolant can flow, in a first cross-sectional plane that is perpendicular to the cylinder axis. In a second cross-sectional plane, which is perpendicular to the cylinder axis and which is arranged in relation to the vertical direction between the first cross-sectional plane and the coolant outflow opening, has a throttle cross-sectional area, which is a cross-sectional area through which coolant can flow. The throttle cross-sectional area is smaller than the distribution cross-sectional area.

Abstract: A system and method for fluidly sealing a cylinder head interface between an engine block and a cylinder head of an internal combustion engine. An example apparatus includes a perimeter seal disposed on an outer periphery of the cylinder head. The perimeter seal has a first surface to abut a cylinder head sealing surface and a second surface to abut an engine block sealing surface. The perimeter seal is configured to prevent fluid from an external environment from entering the cylinder head interface and to allow fluid within the cylinder head interface to vent to the external environment when the fluid is above a predetermined pressure. A first fluid transfer tube seal fluidly seals a first fluid transfer orifice extending between the engine block and the cylinder head. The perimeter seal and the first fluid transfer tube seal are formed as a unitary structure.

Abstract: A liquid cooling circuit includes a liquid reservoir for coolant, a heat-generating module, a conduit fluidly coupling the heat-generating module with the liquid reservoir, and a pump configured to move the coolant through the conduit to cool the heat-generating module. The liquid cooling circuit is configured such that the movement of the coolant relative to the heat-generating module transfers heat from the heat-generating module to the coolant.

Abstract: A lower water jacket of a cylinder head includes a lower/upper exhaust collecting portion cooling portion configured between a lower exhaust collecting portion and an upper exhaust collecting portion by bypassing a lower exhaust collecting portion cooling portion. Besides, cooling water flowing through the lower/upper exhaust collecting portion cooling portion is merely cooling water of the lower water jacket, and cooling water of an upper water jacket does not flow through the lower/upper exhaust collecting portion cooling portion. Therefore, in the lower/upper exhaust collecting portion cooling portion, interference may not occur in cooling water of the two water jackets to restrain smooth flowing, and cooling effects of an area sandwiched by the lower exhaust collecting portion and the upper exhaust collecting portion are further improved.

Abstract: An engine block assembly includes an engine block casting including a plurality of cylinder bores disposed in series, each cylinder having a cylinder wall. Outer engine block walls are peripheral to the cylinder walls. A channel is formed between outer peripheral surfaces of the cylinder walls and the outer engine block walls. A coolant passage fluidly connects through the outer block walls to the channel. A water jacket insert includes an upper flange, a strut portion and a lower flange. A plurality of orifices are formed in the strut portion. A compressible seal attached to the lower flange of the water jacket insert, which is assembled into the channel and conforms to a bottom portion of the channel.

Abstract: A combustion engine is provided that includes an engine block with a fiber material in a resin. The engine block defines a piston bore and a bore liner positioned within the piston bore and includes a substrate and a coating positioned on an interior surface of the substrate. An exterior surface of the substrate defines a retention feature.

Abstract: An opposed-piston engine assembly is disclosed including a first cylinder liner containing a pair of first pistons that move toward one another in one mode of operation and away from one another in another mode of operation. The pistons are coupled to first and second crankshafts. Multiple block segments arranged in a side-by-side abutting relationship form the engine block including a first outboard segment, a first inboard segment, a second inboard segment, and a second outboard segment. Tensile members extend through the block segments tying them together as one structural unit. The first and second inboard segments abut one another at a seam and include bores that cooperate to receive the first cylinder liner. The first cylinder liner includes a liner support collar that is received in counter-bores defined by the first and second inboard segments at the seam between the first and second inboard segments.

Abstract: A cooling system for an engine includes a block-side water jacket divided into a block cooling passage and a bypass passage in the circumferential direction of the block-side water jacket, the block cooling passage allowing a cooling liquid introduced into the block cooling passage to flow into the head-side water jacket via a first communication hole of a cylinder head, and the bypass passage allowing the cooling liquid to bypass the block cooling passage and flow into the head-side water jacket via a second communication hole of the cylinder head. The cooling system further includes a partition separating a downstream end of the block cooling passage and the bypass passage from each other in the circumferential direction. The partition is provided with an adjustment hole which makes a flow of part of the cooling liquid passing through the bypass passage directed to the first communication hole.

Abstract: A cooling water passage structure of internal combustion engine includes a cylinder-block-side cooling water passage, a cylinder-head-side cooling water passage, a heat exchanger, and cooling water passage pipes. The cylinder-block-side cooling water passage is formed inside a cylinder block of an engine to cause cooling water to flow through. The cylinder-head-side cooling water passage is formed inside a cylinder head to cause cooling water to flow through. The heat exchanger is configured to dissipate heat of cooling water to external air to decrease a temperature of the cooling water. The cooling water passage pipes couple the heat exchanger and the engine to exchange cooling water. The cylinder head includes a cooling water inlet. The cooling water passage pipe is coupled to the cooling water inlet. The cooling water from the heat exchanger flows into the cooling water inlet.

Abstract: An engine cooling system for cooling a cylinder head and a cylinder block separately may include a cylinder block having cylinders arranged from a front side to a rear side of an engine with a block water jacket formed therein around the cylinders, a cylinder head fastened to a top side of the cylinder block with a head water jacket formed therein from the front side to the rear side of the engine, a water pump mounted to a front side of the cylinder block for pumping coolant to a front of the block water jacket, and a coolant control valve arranged in a rear side of the cylinder block and the cylinder head to have a first end connected to a rear end of the block water jacket and a second end connected to a rear end of the head water jacket for having the coolant supplied thereto.

Abstract: A multi-mode powertrain system is described, and includes an internal combustion engine having stop/start capability. A method for controlling the multi-mode powertrain system includes circulating coolant to a heater core via an engine fluidic circuit that includes a water jacket of the internal combustion engine when temperature of the coolant is less than an engine fluidic circuit upper temperature threshold and the engine is in an ON state. Coolant is circulated to the heater core via a bypass fluidic circuit that excludes the water jacket of the internal combustion engine when temperature of the coolant is greater than a bypass fluidic circuit lower temperature threshold when the engine is in an OFF state.

Abstract: An engine cylinder head is provided. The engine cylinder head includes a portion of a first combustion chamber, an upper coolant core and a lower coolant core directing heat from the first combustion chamber and including a first coolant passage and a second coolant passage, the first coolant passage and the second coolant passage laying along a lateral axis, at least a portion of the first coolant passage separated from the second coolant passage via first and second walls.

Abstract: An engine is provided. The engine includes a thermal set composite cylinder block including a front engine cover attachment interface and a transmission attachment interface and a cylinder liner integrally molded with the composite cylinder block, the cylinder liner defining a portion of a boundary of a cylinder. The engine further includes a bulkhead insert extending through the thermal set composite cylinder block and is directly coupled to a cylinder head.

Abstract: A cylinder head cleaning method capable of cleaning a cylinder head with an enhanced foreign matter removing rate. The method is used to clean a cylinder head having therein a water jacket including a narrow space portion having a narrow flow path and a large space having a flow path wider than the narrow space portion, and the cylinder head further including holes communicating with the water jacket. Cleaning nozzles are inserted into the water jacket from the holes selected from the holes, clearing liquid is ejected from the cleaning nozzles toward the narrow space portion, and the cleaning liquid flowing from the narrow space portion to the large space is discharged to the outside of the cylinder head from the hole communicating with the space.

Abstract: A cylinder bore wall insulating member has a contact surface that comes in contact with a wall surface of a cylinder bore wall that forms a cylinder block of an internal combustion engine and defines a groove-like coolant passage. An internal combustion engine in which the cylinder bore wall has a uniform temperature may be obtained using the insulating member.

Abstract: A cylinder block (10) includes an inter-bore flow passage (14) between adjacent bores (12). Each inter-bore flow passage (14) is formed by closing an opening-side groove portion (15) continuous from a cylinder block deck face and a bottom-side groove portion (16) with the use of a lid member (20) made of copper, and the lid member (20 is laser-welded to a groove wall face of the opening-side groove portion (15). Before the laser-welding, the lid member (20) has recesses (26) that are interspersed in a direction, in which a laser beam travels, at any one of connected portions at which the lid member (20 is connected to the groove wall face of the opening-side groove portion (15).

Abstract: An internal combustion engine includes a cylinder crankcase and a cylinder head that includes an integrated exhaust manifold, wherein the cylinder crankcase, the cylinder head and the integrated exhaust manifold have a continuous water jacket that forms part of a coolant circuit of the internal combustion engine. To ensure during shut-down cooling and/or warm-up cooling of the exhaust manifold that a majority of the coolant that is fed into the water jacket reaches the exhaust manifold, while only a small portion of the coolant flows around the cylinder through the cylinder crankcase, the coolant circuit includes a collector that communicates via passage openings having reduced opening cross-sections with the water jacket, and coolant channels arranged in extension of a flow direction through the passage-openings lead to the exhaust manifold, while coolant channels branching off laterally behind the passage-openings lead to the cylinder crankcase.

Abstract: The disclosure relates to a method for expediting warm up of an internal combustion engine cylinder block and engine oil utilizing an existing oil coolant circuit. A method for warming up an internal combustion engine with at least one cylinder, a cylinder block which is formed by an upper crankcase half mounted to a lower crankcase half, said lower crankcase half containing an oil sump which is fed, via a supply line, by a coolant jacket, an inlet side of said coolant jacket supplied in turn with oil via the oil sump by an oil pump, the method comprising: releasing oil from the coolant jacket via gravity to reduce a cooling capacity of the internal combustion engine.

Abstract: A thermal management system and method for split cooling and integrated exhaust manifold applications in an automotive engine is provided. The thermal management system includes a cooling circuit that directs coolant through a plurality of components to warm the engine and passenger compartment efficiently, as well as remove excess heat from the engine and promote a constant operating temperature during vehicle operation. The cooling circuit directs liquid coolant, propelled by a coolant pump, through at least one of an engine block cooling jacket, an engine head cooling jacket, and an integrated exhaust manifold (IEM) cooling jacket, along a variety of cooling paths. The cooling circuit also incorporates a plurality of flow control valves to selectively distribute flow of the liquid coolant between a radiator, an engine heater core, and a return path to the coolant pump.

Abstract: An internal combustion engine has a cylinder head having at least one cylinder. A cover is connected to the cylinder head and covers the cylinder and related valve train components. An exhaust gas turbocharger powered by the engine's exhaust system delivers compressed gasses to the intake system. An exhaust gas recirculation system branches off from the exhaust system downstream of the turbocharger and feeds into the intake system upstream of the turbocharger. A coolant-fed charge air cooler is disposed between the cylinder head and the cover, and at a point that is a geodetically highest point in the intake system when the internal combustion engine is in an installed position. This configuration prevents any liquid that has condensed out of the charge air during cooling from collecting in the cooler and/or in the intake system between the cooler and the at least one cylinder.

Abstract: A saddle-type electric vehicle includes a body frame having a head pipe supporting a steering shaft and a main frame portion extending rearward from the head pipe, a battery case provided on the main frame portion behind the head pipe, a battery stored in the battery case and supplying electric power to an electric motor generating traveling power, and a traveling wind path including an inner space of the battery case, wherein a traveling wind inflow port allowing traveling wind to flow in the battery case from front is formed on an upper side of a front portion of the battery case, and a traveling wind outflow port allowing the traveling wind flowing in the battery case to flow out rearward is formed on an upper side of a rear portion of the battery case.

Abstract: The present invention discloses a monoblock engine in which the head and the block of the engine are cast integrally. The engine incorporates a cylinder and water coolant jackets, intake manifold and an exhaust manifold, vertical intake and exhaust valves, core removal holes, and a push-fit type cylinder liner which is secured in place so that leakage of fuel from the cylinder is eliminated. The water coolant jackets for the head and the block are connected using four water jacket gateways or connectors. The monoblock is fitted with the crankcase using a leak proof & robust flange-joint and mechanical fastening system which is easy to install. The invention is embodied for a single cylinder engine as well as multi-cylinder engines. By integrating cylinder head and manifolds with block, the critical joint between head and block and head and intake Manifold will be eliminated. At the same time, gasket and mechanical fasteners for tightening also can be eliminated.

Abstract: Example embodiments for reducing thermal load in one or more exhaust gas lines are provided. One embodiment includes an internal combustion engine with liquid cooling, comprising at least one exhaust gas line, at least one coolant jacket, and a common boundary wall separating the at least one exhaust gas line and the at least one coolant jacket, wherein the common boundary wall includes a surface structure provided on sides of the coolant jacket in at least one locally limited region. In this way, the surface structure on the sides of the coolant jacket may increase heat transfer to reduce thermal loading.

Abstract: A liquid-cooled internal combustion engine, including at least one cylinder block which has a cooling jacket and multiple cylinders. The cooling jacket has a base facing toward a crank chamber and a top facing toward a cylinder head sealing plane. The base has an undulating profile in which a first distance, as measured in the direction of the cylinder axis, between the base of the cooling jacket and the top in the region of at least one first engine transverse plane which encompasses the cylinder axis is greater than a second distance in the region of at least one second engine transverse plane between two adjacent cylinders. In order to reduce cylinder deformation, the cooling jacket has three different heights, in which a third distance between the base of the cooling jacket and the top is smaller in at least one face-end region of the cooling jacket.

Abstract: A spacer arranged inside a water jacket which is formed to surround peripheries of cylinder bores in a cylinder block of an internal combustion engine includes support legs extending in an up-and-down direction from a spacer main body part which partitions the water jacket into an upper and lower cooling water passages. The support legs are disposed in opposite end portions in a cylinder row line direction, where the temperatures of the cylinder bores tend to be lower. Accordingly, even if the flow of cooling water is more or less inhibited by the support legs and the cooling effect deteriorates, it is possible to prevent the temperatures of the respective cylinder bores from becoming different by suppressing the influence to a minimum.

Abstract: In a water-cooled four-cycle engine, an engine core including a cylinder block, a cylinder head and a first crankcase half body is formed as a unitary part cast integrally; a water jacket including a cylinder jacket surrounding a cylinder bore and a head jacket surrounding a combustion chamber is formed in the engine core; and a timing-belt chamber being adjacent to the cylinder jacket is provided in a side portion of the engine core. A first opening portion for forming a first semi-peripheral portion of the cylinder jacket on a side opposite from the timing-belt chamber by casting out is provided in a side surface of the cylinder block. A second opening portion for forming a second semi-peripheral portion of the cylinder jacket and the head jacket by casting out is provided in an upper surface of the cylinder head.

Abstract: A modular unit is composed of a cylinder sleeve and a crankcase for an internal combustion engine. The cylinder sleeve and the crankcase each have a face surface and a cooling water space that at least partly surrounds the cylinder sleeve and is open toward the face surfaces is configured between the cylinder sleeve and the crankcase. A holder ring is provided, which completely covers the cooling water space and at least partially covers the face surface of the cylinder sleeve.

Abstract: A cylinder block side drain is provided in a cylinder block and a crankcase side drain is provided in a crankcase. A jacket cover is provided in an water jacket of the cylinder block. The jacket cover is pressed against the wall of the water jacket on the crankcase side. When discharging the coolant, the water jacket is opened by pushing the jacket cover inward using a coupler and the coolant is discharged to the outer side of the crankcase via the coupler.

Abstract: A four-stroke engine includes a cylinder head, a cylinder body connected to the cylinder head, and a fuel injection valve. The cylinder head defines a combustion chamber, an intake port that communicates with the combustion chamber, and an exhaust port that communicates with the combustion chamber. The fuel injection valve is held by the cylinder head on a side extending from the exhaust port to the cylinder body. The fuel injection valve is arranged so as to supply a fuel mist directly to the combustion chamber by jetting the fuel mist toward the combustion chamber.

Abstract: A method for operating an engine having a cylinder head, comprising: following light-off of an exhaust catalyst from a cold-start condition, circulating liquid coolant through a cooling jacket of the cylinder head, and at a subsequent engine-off condition, draining at least some of the liquid coolant from the cooling jacket. In this way, at a cold start condition, the cooling jacket of the cylinder head may be filled with air, thus decreasing the amount of time needed for the exhaust catalyst to reach a light-off temperature.

Abstract: The cooling device is provided with an engine including a cylinder block, a cylinder head, and a W/J which is a single system as a whole and which causes coolant to flow from the cylinder block to the cylinder head. The W/J branches into first and second inner paths within the cylinder block, and joints together within the cylinder head. The first inner path is provided with an opening and closing valve for permitting and prohibiting the flow of the coolant based on the pressure of the coolant.

Abstract: An intake-side space around intake ports and an exhaust-side lower space around exhaust ports are provided in a main cooling jacket portion. These spaces are connected to each other. In a sub cooling jacket portion, an exhaust-side upper space is provided at a level above the exhaust-side lower space. The main cooling jacket portion and the sub cooling jacket portion are connected to each other via a cylindrical-hole connecting passage extending vertically and separate from each other vertically via a wall portion in another area than the connecting passage. Accordingly, a cooling device of an engine which can restrain the exhaust gas from being cooled too much improperly is provided.

Abstract: A cooling system for a marine engine is provided with various cooling channels which allow the advantageous removal of heat at different rates from different portions of the engine. A split flow of water is conducted through the cylinder head, in opposite directions, to individually cool the exhaust port and intake ports at different rates. This increases the velocity of coolant flow in the downward direction through the cylinder head to avoid the accumulation of air bubbles and the formation of air pockets that could otherwise cause hot spots within the cylinder head. A parallel coolant path is provided so that a certain quantity of water can bypass the engine block and avoid overcooling the cylinder walls.

Abstract: A spacer fitted inside a water jacket of a cylinder block in an internal combustion engine is set so that a space formed between an inner peripheral surface of the spacer and an inner wall surface of the water jacket is smaller than a space formed between an outer peripheral surface of the spacer and an outer wall surface of the water jacket. Accordingly, even if a position of the spacer is shifted in a radial direction, the inner peripheral surface of the spacer comes into abutment on the inner wall surface of the water jacket at first. Thereby, the abutment of the outer peripheral surface of the spacer on the outer wall surface of the water jacket is prevented completely. Therefore, hitting sounds of pistons can be blocked by the space between the outer peripheral surface of the spacer and the outer wall surface of the water jacket.

Abstract: A lower cam housing is formed to be a separate body from a cylinder head and the lower cam housing is arranged at a joint surface of the cylinder head, a first upper oil passage reaching from an oil entry passage to the joint surface is formed inside the cylinder head and an upstream end of the first upper oil passage is opened at the joint surface, and a second upper oil passage through which the oil reaches to the joint surface via an upper side than the joint surface is formed in the lower cam housing, where an upstream end of the second upper oil passage is in communication with the oil entry passage side at the joint surface, and a downstream end of the second upper oil passage is in communication with the first upper oil passage at the joint surface.

Abstract: A spacer covets intermediate portions of respective cylinder bores in a depth direction of a water jacket throughout the entire peripherics of the intermediate portions in the peripheral direction. Accordingly, the intermediate portion of each cylinder bore becomes higher in temperature than any other portion, and is thermally expanded. Thereby, the clearance between the cylinder bore and the corresponding piston increases. Thus, the friction decreases to improve fuel efficiency of an internal combustion engine. Furthermore, the temperature of oil lubricating the intermediate portion of the cylinder bore rises, and the viscosity decreases. Accordingly, the effect of friction reduction is enhanced more. Furthermore, upper and lower portions of the cylinder bores in a cylinder axis direction are sufficiently cooled. Therefore, the cooling performance of a top part and a skirt part of each piston, which tends to become higher in tempera lure, is secured. Accordingly, overheat can be prevented.

Abstract: A method for top-loaded assembly of an internal combustion engine includes providing a carrier base having a lower portion configured as a crankcase and an upper portion having a number of upwardly directed assembly provisions such as a crankshaft bay and at least one cylinder deck. Arranging the crankshaft bay and cylinder deck so that the engine may be assembled from a position above the engine, without the necessity of attaching connecting rods or crankshaft main bearing bolts from underneath the engine.

Abstract: Disclosed is a turbocharged internal combustion engine having at least one intake for supplying the internal combustion engine with fresh air or fresh mixture on an inlet side, a cylinder head having at least two cylinders which are arranged along a cylinder head longitudinal axis and each of which has at least one outlet opening which is adjoined by an exhaust line for discharging the exhaust gases out of the cylinder, the exhaust lines of at least two cylinders being merged on an outlet side, so as to form an integrated exhaust manifold within the cylinder head, to form an overall exhaust line. Also disclosed is at least one exhaust-gas turbocharger which comprises a turbine arranged in the overall exhaust line and a compressor arranged in the at least one intake.

Abstract: A method for machining a cylinder head including a cooling jacket, wherein the fire deck of the cylinder head which is in a raw state is machined by material removal in relation to a reference mark of the cylinder head. The position of the cooling jacket is used as a reference mark.

Abstract: The coolant in the cooling jacket of a dual cycle internal combustion steam engine is intentionally maintained at an elevated temperature that may typically range from about 225° F.-300° F. or more. A non-aqueous liquid coolant is used to cool the combustion chamber together with a provision for controlling the flow rate and residence time of the coolant within the cooling jacket to maintain the temperature of the coolant at a selected elevated temperature that is substantially above the boiling point of water but below the boiling point of the coolant. The coolant is passed from the jacket through a heat exchanger in a first circuit to transfer heat to a vaporizable working fluid such as water and is then returned. An optional second circuit is an intrajacket perturbation circuit within the engine can be used to disrupt and disperse pockets of vapor that may tend to form before damaging hot spots can develop around the combustion chamber.

Abstract: In a water-cooled four-cycle engine, an engine core including a cylinder block, a cylinder head and a first crankcase half body is formed as a unitary part cast integrally; a water jacket including a cylinder jacket and a head jacket is formed in the engine core; and a timing-belt chamber being adjacent to the cylinder jacket is provided in a side portion of the engine core. A first opening portion for forming a first semi-peripheral portion of the cylinder jacket on a side opposite from the timing-belt chamber by casting out is provided in a side surface of the cylinder block. Second and third opening portions for forming a second semi-peripheral portion of the cylinder jacket and the head jacket as well as the timing-belt chamber, respectively, by casting out are provided in an upper surface of the cylinder head.