Abstract: A gas lubrication structure is provided with a high-temperature-side cylinder, an expansion piston lubricated relative to the high-temperature-side cylinder by gas, and a layer provided to the outer peripheral surface of the expansion piston and composed of a material flexible and having a higher linear expansion coefficient than the base material of the expansion piston. The thickness of the layer under normal temperatures is not less than the size of the clearance formed between the layer and the high-temperature-side cylinder. Also, even if the layer is thermally expanded under use conditions, the layer under normal temperatures has a thickness enabling a clearance to be formed between the layer and the high-temperature-side cylinder.

Abstract: In an internal combustion engine, a variable compression ratio mechanism able to change a mechanical compression ratio and a variable valve timing mechanism able to control the closing timing of an intake valve are provided. The mechanical compression ratio is held at a maximum mechanical compression ratio at the engine low load operation side and gradually made to decrease as the engine load increases at the engine high load operation side. The actual compression ratio is held nearly constant at the engine high load operation side and is made to decrease as the engine load decreases at the engine low load operation side.

Abstract: A working gas circulation engine includes a combustion chamber that is supplied with fuel, the combustion product of which is condensed, and working gas that generates power with the use of combustion of the fuel and that has a specific heat ratio higher than that of air, a circulation path that connects an inlet and an outlet of the combustion chamber to each other in such a manner that the working gas is circulated back to the combustion chamber without being released into the atmosphere, and two condensers that are provided in the circulation path, that are supplied with exhaust gas which contains the combustion product and the working gas, and that condense and remove the combustion product.

Abstract: A gas circulation engine includes a combustion chamber to which high-pressure fuel in a first high-pressure fuel supply passage, an oxidant and working gas are supplied; a circulation path that connects an intake-side portion and an exhaust-side portion of the combustion chamber to each other; a fuel bleed-off tank into which the high-pressure fuel in the first high-pressure fuel supply passage is bled off; a fuel bleed-off valve that permits or shuts off communication between the first high-pressure fuel supply passage and the fuel bleed-off tank; and a fuel bleed-off control unit that permits communication between the first high-pressure fuel supply passage and the fuel bleed-off tank by opening the fuel bleed-off valve when the engine is stopped, the communication between the first high-pressure fuel supply passage and the fuel bleed-off tank being shut off during operation of the engine.

Abstract: A combustion chamber to which a reactant and a working gas whose specific heat ratio is higher than that of air are supplied and in which the working gas can expand following a reaction of the reactant, a circulation path capable of re-supplying the working gas into the combustion chamber by causing the working gas to circulate from an exhaust side to a suction side of the combustion chamber, supplying means that supplies the reactant, a concentration detection means capable of detecting a concentration of the reactant in the circulation path, and a supply control means that sets at least a first supply rate of the reactant by the supplying means in a time for starting based on the concentration of the reactant detected by the concentration detection means before a start of supplying of the reactant by the supplying means are included and so proper starting can be assured.

Abstract: An exhaust heat recovery apparatus includes: an exhaust heat recovery unit that produces motive power by recovering thermal energy from exhaust heat, wherein the produced motive power is combined with motive power produced by a heat engine and is output together therewith; an auxiliary that is driven by at least the exhaust heat recovery unit; and a power transmission-switching device that is provided between the heat engine and the exhaust heat recovery unit, the same power transmission-switching device being provided between the heat engine and the auxiliary, and that cuts off the connection between the heat engine and the exhaust heat recovery unit when there is no request to drive the heat engine. Thus, it becomes possible to effectively use the surplus motive power produced by the exhaust heat recovery unit when there is no request to drive the heat engine.

Abstract: An engine provided with a variable timing mechanism (B) able to control a closing timing of an intake valve (7) and a variable compression ratio mechanism (A) able to change a mechanical compression ratio and controlling the closing timing of the intake valve (7) to control the amount of intake air fed into a combustion chamber (5). To obtain an output torque in accordance with the required torque even when the atmospheric pressure changes, when the atmospheric pressure falls, the closing timing of the intake valve (7) is made to approach intake bottom dead center and the mechanical compression ratio is reduced.

Abstract: During starting of an engine that has a circulation path through which argon, used as working gas, is circulated back to a combustion chamber and that uses hydrogen as fuel during operation, oxygen is supplied in such a manner that the oxygen supply ratio is higher than that used during normal operation. Thus, the entirety of hydrogen supplied into the combustion chamber reacts with oxygen and is burned. When the engine is being started, because gas is not turbulent enough, hydrogen and oxygen are likely to be mixed poorly. Therefore, when oxygen is supplied in such a manner that the ratio of oxygen supply amount to the hydrogen supply amount is higher than the theoretical ratio, even if oxygen and hydrogen are not mixed so well, the chance that hydrogen contacts oxygen is increased. As a result, combustion takes place in a more appropriate manner, which improves the engine startability.

Abstract: In an internal combustion engine, a variable compression ratio mechanism (A) able to change a mechanical compression ratio and a variable valve timing mechanism (B) able to control the closing timing of an intake valve (7) are provided. The mechanical compression ratio is held at a maximum mechanical compression ratio at the engine low load operation side and gradually made to decrease as the engine load increases at the engine high load operation side. Combustion is performed by a stoichiometric air-fuel ratio at the engine high load operation side, and combustion is performed by a lean air-fuel ratio at the engine low load operation side where the mechanical compression ratio becomes the maximum mechanical compression ratio.

Abstract: An exhaust heat recovery system includes a plurality of Starling engines. Heaters of the Starling engines are disposed in an exhaust passage that is a heat medium passage. An inside of the exhaust passage is partitioned with a partitioning member into a first exhaust passage and a second exhaust passage. The heater of the Starling engine disposed on an upstream side in a flowing direction of exhaust gas is provided in the first exhaust passage, and the heater of the Starling engine disposed on a downstream side in the flowing direction of the exhaust gas is provided in the second exhaust passage.

Abstract: A high temperature side cylinder of a Stirling engine is composed of a sleeve and a cylinder block. A high temperature side piston makes a reciprocating motion in the sleeve. The sleeve is connected to a heater that heats a working fluid of the Stirling engine so that heat of the heater is transmitted. A cylinder block is disposed outside of the sleeve. A predetermined interval is formed between the sleeve and the cylinder block, and an air layer is formed in the predetermined interval.

Abstract: A Stirling engine includes a plurality of ?-type Stirling cycle mechanisms, each of which includes a first piston and a second piston and pressurizes a crankcase space. The mechanisms are coupled to each other via a common rotary shaft so that each of the mechanisms generates a torque variation waveform in which the number of periods per rotation is two.

Abstract: In a Stirling engine, a casing houses therein component elements of the Stirling engine, including a high-temperature-side cylinder, a high-temperature-side piston, a connecting rod, a crankshaft, etc. A pressure control device determines whether the pressure of the gas charged in the casing has declined. If the pressure of the gas has declined, the pressure control device drives a pump to pressurize the gas charged in the casing.

Abstract: An internal combustion engine provided with a variable compression ratio mechanism able to change a mechanical compression ratio and an actual compression action start timing changing mechanism able to change a start timing of an actual compression action. An amount of intake air in accordance with the required load is fed into a combustion chamber by controlling the closing timing of the intake valve, while a pressure, temperature or density in the combustion chamber at the end of a compression stroke is maintained substantially constant regardless of the engine load by controlling the mechanical compression ratio.

Abstract: A spark ignition internal combustion engine includes a variable expansion ratio mechanism which can alter the mechanical expansion ratio, and an exhaust variable valve mechanism which can alter the timing for opening an exhaust valve. The mechanical expansion ratio and the timing for opening the exhaust valve are set depending on the engine load such that the mechanical expansion ratio increases and the timing for opening the exhaust valve is retarded to the exhaust bottom dead center side as the engine load decreases. By setting the mechanical expansion ratio in such a manner depending on the engine load, thermal efficiency can be enhanced as compared with a case where the mechanical expansion ratio is set to make the actual compression rate constant for example. Consequently, a spark ignition internal combustion engine exhibiting high thermal efficiency is provided.

Abstract: A piston is coupled to a connecting rod which is rotatably coupled to a crankshaft via an extension rod. With the configuration, reciprocating motion of the piston is transmitted to the crankshaft and converted to rotational motion. At both ends of the extension rod, a piston-side joint mechanism and a crankshaft-side joint mechanism each constructed by a spherical sliding bearing are provided. The piston is coupled to the extension rod via the piston-side joint mechanism, and the extension rod is coupled to the connecting rod via the crankshaft-side joint mechanism.

Abstract: An internal combustion engine comprises a variable compression ratio mechanism capable of varying the mechanical compression ratio and a variable valve timing mechanism capable of controlling the closing timing of an intake valve. In an engine low-load operation, the mechanical compression ratio is maintained at a maximum mechanical compression ratio. In an engine high-load operation, the mechanical compression ratio is gradually decreased as the engine load increases. In the engine high-load operation, a load at which a predetermined mechanical compression ratio lower than the maximum mechanical compression ratio is obtained is preset, and a throttle valve is closed in the range of loads lower than the preset load.

Abstract: In an internal combustion engine, a variable compression ratio mechanism able to change a mechanical compression ratio and a variable valve timing mechanism able to control the closing timing of an intake valve are provided. The mechanical compression ratio is made to be the maximum mechanical compression ratio at low load operation regions excluding idling operation, while during idling operation, the mechanical compression ratio is made lower than the maximum mechanical compression ratio.

Abstract: A Stirling engine is provided with a fluid passage that connects a low temperature-side actuating fluid space and a crankcase inner space, and a passage opening/closing valve that is provided in the fluid passage and that opens and closes the fluid passage. Upon stopping of the Stirling engine, the passage opening/closing valve enables communication through the fluid passage, at a region at which the piston floats in the cylinder. This region is determined based on the pressure of an actuating fluid in the actuating fluid space and the rotational speed of a crankshaft of the Stirling engine.

Abstract: A Stirling engine has a fluid passage that connects a low temperature-side actuating fluid space and a crankcase inner space, and a passage opening/closing valve that is provided in the fluid passage and that opens and closes the fluid passage. The passage opening/closing valve enables communication through the fluid passage upon startup of the Stirling engine, and shuts off communication through the fluid passage when the rotational speed of the crankshaft of the Stirling engine is equal to or greater than a pre-established start-enabling rotational speed.