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: 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: 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 heat exchanger for a stirling engine 10A of a twin-cylinder ? type includes a heat transfer tube group 70A formed with heat transfer tubes 71A causing a working fluid of the stirling engine 10A to flow between a high-temperature cylinder 20 and a low-temperature cylinder 30 arranged linearly and parallel to each other in the stirling engine. The heat transfer tube group 70A includes a rising section G1 extending upward, a falling section G2 extending downward, and a connecting section G3 connecting the rising section G1 and the falling section G2 in a turn-back manner, where the heat transfer tube group 70A is regarded as extending from one end or the other end thereof.

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. At the time of engine low load operation, the mechanical compression is made the maximum so that the expansion ratio becomes 20 or more. Further, at the time of engine low load operation, in part of the operating region or all of the operating region, the actual compression ratio is lowered compared with the time of the engine high load operation and, at the time of engine low load operation, at least when the actual compression ratio is being lowered compared with the time of engine high load operation, the throttle valve is made to close.

Abstract: A working gas circulation type engine includes a combustion chamber in which a working gas having a ratio of specific heats higher than that of air can be expanded by combustion of a fuel, a circulation path capable of circulating a gas containing the working gas from a gas exhaust side to a gas suction side of the combustion chamber and supplying the gas containing the working gas to the combustion chamber again, and a control device that changes a control parameter for controlling the combustion of the fuel based on a ratio of specific heats of the gas circulating in the circulation path. Therefore, there can be provided the working gas circulation type engine capable of obtaining a stable output.

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 resupplying 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: 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: The working gas circulation engine includes a circulation route capable of circulating gas containing the working gas from an exhaust side to an intake side of a combustion chamber and resupplying to the combustion chamber and provided with a removing device to remove a product generated with a reaction from the circulating gas, a supplying device capable of supplying plural kinds of reactant gas to the combustion chamber or the circulation route, a pressure detecting device capable of detecting pressure in the circulation route, and a control unit that controls supply amount of at least one kind of the reactant gas to be supplied from the supplying device.

Abstract: An exhaust heat recovery apparatus includes a Stirling engine and a clutch. The Stirling engine produces motive power by recovering thermal energy from exhaust gas discharged from an internal combustion engine from which exhaust heat is recovered. The motive power produced by the Stirling engine is transmitted to an internal combustion engine transmission through the clutch and an exhaust heat recovery device transmission, and combined with the motive power produced by the internal combustion engine through the internal combustion engine transmission, and is output from an output shaft. If rapid acceleration is required, and the increase in the rotation speed of the Stirling engine therefore lags behind the increase in the rotation speed of the internal combustion engine, the clutch is released. With this configuration, reduction in the power output from the heat engine, from which exhaust heat is recovered, is restricted, and the degradation of the acceleration performance is minimized.

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. At the time of engine startup, the closing timing of the intake valve (7) is made the most delayed position so that the least intake air is fed to the inside of the combustion chamber (5) and the mechanical compression ratio is made the maximum compression ratio.

Abstract: An exhaust pipe through which an exhaust port of an internal combustion engine and a catalyst for purifying an exhaust gas of the internal combustion engine are connected to each other includes a porous portion that is provided on at least a part of an inner peripheral face of the exhaust pipe. A thermal conductivity that the porous portion exhibits in a high temperature state where a temperature of the exhaust gas is as high as it is required to radiate a heat of the exhaust gas through the exhaust pipe is at least ten times higher than a thermal conductivity that the porous portion exhibits in a low temperature state where the temperature of the exhaust gas is as low as it is required to warm the catalyst up.

Abstract: An exhaust heat recovery apparatus includes a reciprocating internal combustion engine in which a piston reciprocates in a cylinder to generate motive power; and a Stirling engine that recovers the thermal energy of the exhaust gas discharged from the internal combustion engine and converts the thermal energy into kinetic energy. The Stirling engine is united with the internal combustion engine. A heater that the Stirling engine includes is disposed in an exhaust manifold of the internal combustion engine. With this configuration, it is possible to restrict reduction in the power output from the exhaust heat recovery means.

Abstract: A control device for a Stirling engine including: two cylinder units; and a decompression portion that brings about a decompression effect of reducing a degree of compression of a working fluid that flows back and forth between the two cylinder units, by letting out the working fluid that flow back and forth between the two cylinder units, when the Stirling engine is started; the control device including a control portion that controls the decompression portion so that the decompression effect is gradually weakened after the Stirling engine is started.

Abstract: A high expansion ratio internal combustion engine includes: a variable compression ratio mechanism that varies a mechanical compression ratio of the internal combustion engine; and a variable valve train in which some valve(s) of a plurality of intake valves is phase-variable and the remaining valve(s) is phase-fixed, the variable valve train being configured such that a working angle of the phase-variable intake valve is larger than a working angle of the phase-fixed intake valve, wherein a valve-open timing of the phase-variable intake valve is retarded after a valve-open timing of the phase-fixed intake valve when the internal combustion engine is under low-load operating state.

Abstract: A working gas circulation engine includes a combustion chamber that can expand a working gas, which has a specific heat ratio higher than that of the air, with the combustion between an oxidizing agent and a fuel; a circulation path that can allow the working gas to circulate from a suction side to an exhaust side of the combustion chamber and can supply the same again to the combustion chamber; a feed means that can feed the gas in a pressure-reduction target section, which is the section whose pressure is to be reduced, to the outside, and a control means that operates the feed means for feeding the gas in the pressure-reduction target section, when the pressure in the pressure-reduction target section is higher than a predetermined pressure that is set in advance.

Abstract: A silica structure includes mesoporous silica spheres; and connection portions each of which includes metal oxide, and each of which connects the mesoporous silica spheres to each other.

Abstract: A Stirling engine includes a high-temperature side cylinder and an expansion piston that is subjected to gas lubrication, or more specifically static pressure gas lubrication, relative to the high-temperature side cylinder and has a layer on an outer peripheral surface thereof, the layer being formed from a flexible material having a higher linear expansion coefficient than a base material of the expansion piston, wherein a booster pump and a ECU are provided as a contact avoiding device to prevent the expansion piston from contacting the high-temperature side cylinder when an engine operation is stopped until a temperature of the expansion piston can be suppressed below a predetermined value.

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 working gas circulation engine includes a combustion chamber that can expand a working gas, which has a specific heat ratio higher than that of the air, with the combustion between an oxidizing agent and a fuel; a circulation path that can allow the working gas to circulate from a suction side to an exhaust side of the combustion chamber and can supply the same again to the combustion chamber; a feed means that can feed the gas in a pressure-reduction target section, which is the section whose pressure is to be reduced, to the outside, and a control means that operates the feed means for feeding the gas in the pressure-reduction target section, when the pressure in the pressure-reduction target section is higher than a predetermined pressure that is set in advance.