JP2014047722A - External combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an external combustion engine for improving heat recovery efficiency.SOLUTION: An external combustion engine 1 having an evaporator 2 and a condenser 3 is switched among a communication state for communicating a gas side of the evaporator 2 and a gas side of a cylinder 4b by a gas side rotary valve unit 5, a communication state for communicating a gas side of the condenser 3 and the gas side of the cylinder 4b, and a communication state for communicating the gas side of the evaporator 2, the gas side of the condenser 3 and the gas side of the cylinder 4b, and is switched between a communication state for communicating a liquid side of the condenser 3 and a liquid side of the cylinder 4b by a liquid side rotary valve unit 6, a communication state for communicating a liquid side of the evaporator 2 and the liquid side of the cylinder 4b, and a communication state for communicating the liquid side of the evaporator 2, the liquid side of the condenser 3 and the liquid side of the cylinder 4b, so as to reciprocate a piston 4a using high-pressure gas of the evaporator 2 and low-pressure gas of the condenser 3.

Description

  The present invention relates to an external combustion engine.

  The external combustion engine uses a heat source outside the engine (for example, waste heat of a vehicle engine), and converts the heat energy of the heat source into kinetic energy by evaporating / condensing the working medium. An example of the external combustion engine is a Rankine cycle in which a working medium is circulated by a pump. For example, Patent Document 1 is known as a Rankine cycle of an external combustion engine. In Patent Document 1, in a waste heat recovery apparatus for an internal combustion engine, an evaporator that generates high-pressure steam using the waste heat of the internal combustion engine as a heat source, an expander that generates output by expansion of the high-pressure steam, and a low pressure from the expander It has a condenser for liquefying steam and a pump for pressurizing and supplying liquid from the condenser. In each vane piston unit of the expander, the piston is operated by expansion of high-pressure steam to rotate the rotor via the vane. At the same time, it is disclosed that the rotor is rotated through the vane by the expansion of the low-pressure gas due to the pressure drop of the high-pressure gas.

JP 2000-320301 A

  However, in the case of a conventional external combustion engine, like the external combustion engine disclosed in Patent Document 1, the expander uses only the high-pressure gas from the evaporator to convert it into kinetic energy. Therefore, there is room for improvement in the efficiency of heat recovery from the heat source.

  Then, this invention makes it a subject to provide the external combustion engine which improves heat recovery efficiency.

  An external combustion engine according to the present invention includes an evaporator that evaporates a liquid working medium by a heat source, a condenser that condenses a gaseous working medium, a piston that floats on the liquid working medium, and a cylinder that is disposed vertically. A gas unit first communication state in which the gas side of the evaporator and the gas side of the cylinder communicate with each other, a gas side second communication state in which the gas side of the condenser and the gas side of the cylinder communicate with each other, Gas side switching means for switching between the gas side of the condenser and the gas side third communication state for communicating the gas side of the condenser and the gas side of the cylinder, and the liquid side communicating between the liquid side of the condenser and the liquid side of the cylinder A first communication state, a liquid side second communication state that connects the liquid side of the evaporator and the liquid side of the cylinder, and a liquid side that connects the liquid side of the evaporator and the liquid side of the condenser and the liquid side of the cylinder Switch between 3rd communication state Characterized in that it comprises a side switching means.

  In the evaporator of the external combustion engine, by heating the liquid working medium with a heat source, the liquid working medium evaporates and becomes high-pressure gas. In the condenser, the gaseous working medium condenses into a low-pressure gas and becomes a liquid working medium. In particular, this external combustion engine is provided with a piston unit, a gas side switching means and a liquid side switching means in addition to the evaporator and the condenser. The piston unit has a piston and a cylinder. The piston is a float type free piston that floats against a liquid working medium. The cylinder is arranged in the vertical direction, the lower part is filled with a liquid working medium that sinks due to gravity, and the upper part across the piston is filled with a gaseous working medium. Accordingly, in the cylinder, the piston reciprocates up and down between the gas working medium and the liquid working medium in a state where the piston floats on the liquid working medium. The gas side switching means includes a gas side first communication state (the gas side of the evaporator and the gas side of the cylinder are in communication) and a gas side second communication state (the gas side of the condenser and the gas side of the cylinder are in communication). And the gas side third communication state (the gas side of the evaporator and the gas side of the condenser communicate with the gas side of the cylinder). On the other hand, the liquid side switching means includes a liquid side first communication state (the liquid side of the condenser and the liquid side of the cylinder are in communication) and a liquid side second communication state (the liquid side of the evaporator and the liquid side of the cylinder). Communication) and the liquid side third communication state (the liquid side of the evaporator and the liquid side of the condenser and the liquid side of the cylinder are in communication). When the gas side switching means switches to the gas side first communication state and the liquid side switching means switches to the liquid side first communication state, the high pressure gas from the evaporator pushes the piston from above and the low pressure gas from the condenser from below The piston is pulled through the liquid working medium, and the piston moves downward. Next, when the gas side switching means switches to the gas side third communication state and the liquid side switching means switches to the liquid side third communication state, the evaporator, the condenser and the piston unit are in pressure equilibrium, and the piston is in the reference state. Return. Next, when the gas side switching means switches to the gas side second communication state and the liquid side switching means switches to the liquid side second communication state, the high-pressure gas in the evaporator pushes the piston from below through the liquid working medium. At the same time, the low-pressure gas in the condenser pulls the piston from above, and the piston moves upward. Next, when the gas side switching unit switches to the gas side third communication state and the liquid side switching unit switches to the liquid side third communication state, the piston returns to the reference state as described above. By repeating this operation, the piston reciprocates in the vertical direction within the cylinder, and kinetic energy is extracted by the reciprocating motion of the piston. It is also possible to convert this kinetic energy into electrical energy. In this way, this external combustion engine uses the high-pressure gas of the evaporator and the low-pressure gas of the condenser to switch the piston by switching the gas-side and liquid-side communication states of the evaporator and the condenser and the piston unit. It can be reciprocated, and the recovery efficiency of the heat energy of the heat source can be improved.

  In the above external combustion engine of the present invention, the gas side switching means is constituted by a gas side rotary valve unit that switches the gas side first to third communication states by rotating a rotary valve in which a plurality of flow paths are formed, The liquid side switching means includes a liquid side rotary valve unit that switches the liquid side first to third communication states by rotating a rotary valve in which a plurality of flow paths are formed. It is preferable that the rotary valve of the liquid side rotary valve unit is rotated in synchronism with the same rotational speed.

  Each switching means of the external combustion engine is constituted by a rotary valve unit including a rotary valve, and a plurality of flow paths are formed in the rotary valve. In the gas side rotary valve unit, by rotating the rotary valve, the gas side of the evaporator and / or the gas side of the condenser and the gas side of the cylinder are communicated with each other in each flow path. The side second communication state and the gas side third communication state can be switched. In the liquid-side rotary valve unit, the liquid side of the evaporator and / or the liquid side of the condenser and the liquid side of the cylinder communicate with each other by rotating the rotary valve, and the liquid-side first communication state and the liquid The side second communication state and the liquid side third communication state can be switched. By rotating the rotary valve of the gas side rotary valve unit and the rotary valve of the liquid side rotary valve unit synchronously at the same rotational speed, the gas side first communication state and the liquid side first communication state are synchronized. The gas side second communication state and the liquid side second communication state are switched synchronously, and the gas side third communication state and the liquid side third communication state are switched synchronously. As described above, the external combustion engine can be reduced in size by configuring the switching means with the rotary valve having a plurality of flow paths for switching the communication state, and the three types of the external combustion engine can be achieved by simply rotating the rotary valve. Since the communication state can be switched, the power required for switching can be reduced and control is also easy.

  In the above external combustion engine of the present invention, it is preferable to control the frequency of the reciprocating motion of the piston based on the rotational speeds of the rotary valve of the gas side rotary valve unit and the rotary valve of the liquid side rotary valve unit.

  In this external combustion engine, by increasing the rotational speed of the gas-side and liquid-side rotary valves, the frequency of piston reciprocation increases (the number of piston reciprocations per unit time increases), and the required thermal energy and More kinetic energy is extracted. In an external combustion engine, the frequency of the reciprocating motion of the piston is lowered by lowering the rotational speed of the gas-side and liquid-side rotary valves (reducing the number of reciprocating motions of the piston per unit time), and the required thermal energy. And less kinetic energy is extracted. For example, as the heat energy (heat amount) of the heat source increases, the rotational speed of the rotary valve is increased and the frequency of the reciprocating motion of the piston is increased, so that more kinetic energy can be extracted. Thus, this external combustion engine can control the frequency of the reciprocating motion of the piston by the rotational speeds of the gas-side and liquid-side rotary valves, and can control the output of the external combustion engine.

  According to the present invention, the piston is reciprocated using the high pressure gas of the evaporator and the low pressure gas of the condenser by switching the gas side and liquid side communication states of the evaporator and the condenser and the piston unit. Thus, the recovery efficiency of the heat energy of the heat source can be improved.

It is a schematic block diagram of the external combustion engine which concerns on this Embodiment. It is a schematic sectional drawing along the AA line of FIG. FIG. 2 is an operation diagram of the external combustion engine of FIG. 1, (a) to (c) are processes in which the piston moves downward, (d) is a process in which the piston returns to the reference state, and (e) to (g) ) Is a process in which the piston moves upward, and (h) is a process in which the piston returns to the reference state.

  Hereinafter, an embodiment of an external combustion engine according to the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected about the element which is the same or it corresponds in each figure, and the overlapping description is abbreviate | omitted.

  The external combustion engine according to the present embodiment is an engine that recovers thermal energy from a heat source outside the engine, such as waste heat, and is mounted on a vehicle, for example, and uses cooling water or exhaust gas of the vehicle engine as a heat source. The external combustion engine according to the present embodiment is a system corresponding to a Rankine cycle that includes an evaporator and a condenser and circulates a working medium between the evaporator and the condenser.

  With reference to FIG.1 and FIG.2, the external combustion engine 1 which concerns on this Embodiment is demonstrated. FIG. 1 is a schematic configuration diagram of an external combustion engine according to the present embodiment. FIG. 2 is a schematic cross-sectional view along the line AA in FIG.

  In order to use the high pressure gas generated in the evaporator and the low pressure gas generated in the condenser at the same time, the external combustion engine 1 simultaneously causes the high pressure gas and the low pressure gas to act on the free piston by rotating the rotary valve. Reciprocate up and down. Therefore, the external combustion engine 1 includes an evaporator 2, a condenser 3, a piston unit 4, a gas side rotary valve unit 5 (gas side switching means), a liquid side rotary valve unit 6 (liquid side switching means), and a connecting pipe 7a. ~ 7f. The external combustion engine 1 also includes a controller, a motor, and the like (not shown).

  The evaporator 2 heats the working medium with a heat source to be collected, and evaporates (vaporizes) the liquid working medium. In the evaporator 2, one side is a liquid working medium, and the other side is a vaporized working medium. The heated working medium is at a high pressure. About the evaporator 2, the structure of a known general evaporator is employable.

  The condenser 3 cools (dissipates heat) the working medium with a cooling heat source, and condenses (liquefies) the gaseous working medium. In the condenser 3, one side is a gaseous working medium, and the other side is a liquefied liquid working medium. The cooled working medium is at a low pressure. About the condenser 3, the structure of a well-known general condenser is employable.

  Various working media can be used and are not particularly limited. For example, when using outside air (air) as a cooling heat source in the condenser 3, the working medium preferably has a boiling point near the outside air temperature.

  The piston unit 4 includes a piston 4a and a cylinder 4b. The piston 4a is a disk-shaped member that is made of a material having a specific gravity smaller than that of the working medium and has a predetermined thickness. The piston 4a is a float type free piston that floats against a liquid working medium. The cylinder 4b is a cylindrical member, and the piston 4a is movably accommodated therein. The cylinder 4b is arranged in the vertical direction (vertical direction). Accordingly, the cylinder 4b is filled with a liquid working medium sinking downward due to gravity, and a gas working fluid is filled on the upper side across the piston 4a. Note that a spring 4c may be provided on the upper surface of the piston 4a, and the movement amount of the piston 4a may be adjusted by the spring 4c.

  As the piston 4a reciprocates in the vertical direction within the cylinder 4b, the heat energy of the heat source is extracted as kinetic energy. Furthermore, for example, by attaching a linear generator to the piston unit 4, the kinetic energy is converted into electric energy, and the heat energy of the heat source can be recovered as electric energy (power regeneration). Also, a kinetic energy (power) can be recovered as it is by attaching a crank mechanism to the piston 4a.

  The gas-side rotary valve unit 5 and the liquid-side rotary valve unit 6 have the same structure using a rotary valve, and the evaporator 2, the condenser 3, and the piston unit 4 are rotated by rotating the rotary valve. Switch communication status. The same structure will be described with reference to FIG. 2 in the structure of the gas side rotary valve unit 5.

  The gas side rotary valve unit 5 includes a casing 5a and a rotary valve 5b. The casing 5a is a hollow cylindrical member whose both ends are closed, and houses the rotary valve 5b in a rotatable state. The rotary valve 5b is a cylindrical member, and three flow paths 5c, 5d, and 5e are formed in the cylindrical member. The flow path 5c is a hole that is formed perpendicular to the central axis of the columnar member (the rotation axis C of the rotary valve 5b) and penetrates from the side surface of the columnar member to the opposite side surface. The flow path 5c is a communication path that connects the gas side of the evaporator 2, the gas side of the condenser 3, and the gas side of the cylinder 4b by the rotation of the rotary valve 5b. The flow path 5d is a hole formed on the central axis of the cylindrical member (perpendicular to the flow path 5c) and penetrating from the center of the flow path 5c to one end surface of the cylindrical member. The flow path 5d is a communication path that is always connected to the gas side of the cylinder 4b, and is also connected to the flow path 5c and the flow path 5e. The flow path 5e is a hole penetrating from the central part of the flow path 5c to the side surface of the cylindrical member, and is formed perpendicular to the flow path 5c and also perpendicular to the flow path 5d. The flow path 5e is a communication path that connects the gas side of the evaporator 2 and the gas side of the cylinder 4b by the rotation of the rotary valve 5b, and also connects the gas side of the condenser 3 and the gas side of the cylinder 4b. It also becomes a passage. The channel 5c and the channel 5e are channels on the same plane, and the channel 5d is a channel on a plane orthogonal to the planes of the channels 5c and 5e. 1 and 3, the flow path 5c, the flow path 5d, and the flow path 5e are drawn on the same plane, but this is for easy understanding of the communication state.

  Two through holes are formed in the side wall of the cylindrical member of the casing 5a at positions corresponding to both ends of the flow path 5c (and also corresponding to one end of the flow path 5e by rotating the rotary valve 5b). (Valve inlet / outlet ports 5f, 5g) are formed. The valve inlet / outlet port 5f is connected to a connecting pipe 7a connected to the gas side of the evaporator 2. The valve inlet / outlet port 5 g is connected to a connection pipe 7 b connected to the gas side of the condenser 3. Further, a through hole (valve inlet / outlet port 5h) is formed in a wall of one end portion of the cylindrical member of the casing 5a at a position corresponding to one end of the flow path 5d (on the central axis of the columnar member of the rotary valve 5b). ing. The valve inlet / outlet port 5h is connected to a connecting pipe 7e connected to the gas side of the cylinder 4b.

  It should be noted that by adjusting the angle θ of the valve inlet / outlet ports 5f, 5g, 6f, 6g shown in FIG. 1, the amount of gas discharged / inflow from the evaporator 2 and condenser 3 and the piston unit 4 (cylinder 4b) Liquid discharge / inflow can be set. Considering the ability of the evaporator 2 to evaporate and vaporize the liquid working medium (evaporation time, gas flow rate, etc.) and the ability of the condenser 3 to condense and liquefy the gaseous working medium (condensation time, liquid flow rate, etc.) Thus, the valve inlet / outlet port angle θ may be adjusted.

  Moreover, the rotating shaft 5i is attached on the center axis | shaft of the other end surface of the cylindrical member of the rotary valve 5b. The rotary shaft 5i extends through the wall of the other end of the cylindrical member of the casing 5a to the outside of the casing 5a, and a pulley 5j is attached to the other end. A belt (not shown) is hung on the pulley 5j. A pulley (not shown) of the liquid-side rotary valve unit 6 is also hung on the belt, and a pulley to which an output shaft of a motor (not shown) is attached is also hung. The rotary valves 5b and 6b are rotated by the motor through the pulley and the belt. In addition, it is good also as a structure which transmits rotation of a motor using other mechanisms, such as a gear, instead of a pulley and a belt.

  The motor is controlled by a controller (not shown). A controller (an ECU [Electronic Control Unit] when the external combustion engine 1 is mounted on a vehicle) is a control device including a CPU [Central Processing Unit], a ROM [Read Only Memory], a RAM [Random Access Memory], and the like. In the controller, the target rotational speed of the rotary valves 5b and 6b (or the target frequency of the piston 4a) is set, the target rotational speed of the motor to be the target rotational speed (or target frequency) is set, and the target Supply current to the motor to achieve rotation speed. When setting the target rotational speed of the rotary valve (or piston target frequency), for example, the target rotational speed or target frequency is set based on the heat energy (heat input) of the recovered heat source, and the target rotational speed increases as the heat energy increases. Or increase the target frequency.

  In the gas-side rotary valve unit 5, both ends of the flow path 5c communicate twice with the valve inlet / outlet ports 5f and 5g and one end of the flow path 5e communicates once with the valve inlet / outlet port 5f while the rotary valve 5b rotates once. Then, one end of the flow path 5e communicates with the valve inlet / outlet port 5g once. When both ends of the channel 5c communicate with the valve inlet / outlet ports 5f and 5g, the connecting pipe 7e, the valve inlet / outlet port 5h, the channel 5d, the channel 5c, the valve inlet / outlet port 5f, and the connecting pipe 7a are connected to the gas side of the evaporator 2 And the gas side of the cylinder 4b are in communication with each other, and the connecting pipe 7e, the valve inlet / outlet port 5h, the flow path 5d, the flow path 5c, the valve inlet / outlet port 5g, and the connecting pipe 7b are connected to connect the gas side of the condenser 3 to the cylinder The gas side of 4b will be in a communication state. When one end of the flow path 5e communicates with the valve inlet / outlet port 5f, the connecting pipe 7e, the valve inlet / outlet port 5h, the flow path 5d, the flow path 5e, the valve inlet / outlet port 5f, the connecting pipe 7a are connected, and the gas side of the evaporator 2 and the cylinder The gas side of 4b will be in a communication state. When one end of the flow path 5e communicates with the valve inlet / outlet port 5g, the connecting pipe 7e, the valve inlet / outlet port 5h, the flow path 5d, the flow path 5e, the valve inlet / outlet port 5g, and the connecting pipe 7b are connected, and the gas side of the condenser 3 and the cylinder The gas side of 4b will be in a communication state.

  In the liquid-side rotary valve unit 6, both ends of the flow path 6c communicate twice with the valve inlet / outlet ports 6f and 6g and one end of the flow path 6e communicates once with the valve inlet / outlet port 6f while the rotary valve 6b rotates once. Then, one end of the flow path 6e communicates once with the valve inlet / outlet port 6g. When both ends of the flow path 6c communicate with the valve inlet / outlet ports 6f and 6g, the connecting pipe 7f, the valve inlet / outlet port, the flow path 6d, the flow path 6c, the valve inlet / outlet port 6f, and the connecting pipe 7c are connected to the liquid side of the evaporator 2. The liquid side of the cylinder 4b is in communication with the connecting pipe 7f, the valve inlet / outlet port, the flow path 6d, the flow path 6c, the valve inlet / outlet port 6g, and the connecting pipe 7d to connect the liquid side of the condenser 3 and the cylinder 4b. The liquid side is in communication. When one end of the flow path 6e communicates with the valve inlet / outlet port 6f, the connecting pipe 7f, the valve inlet / outlet port, the flow path 6d, the flow path 6e, the valve inlet / outlet port 6f, and the connecting pipe 7c are connected, and the liquid side of the evaporator 2 and the cylinder 4b The liquid side is in communication. When one end of the flow path 6e communicates with the valve inlet / outlet port 6g, the connecting pipe 7f, the valve inlet / outlet port, the flow path 6d, the flow path 6e, the valve inlet / outlet port 6g, and the connecting pipe 7d are connected, and the liquid side of the condenser 3 and the cylinder 4b The liquid side is in communication.

  Since the rotary valve 5b of the gas side rotary valve unit 5 and the rotary valve 6b of the liquid side rotary valve unit 6 are rotated by the same motor, they are rotated synchronously at the same rotational speed. The rotary valve 5b and the rotary valve 6b are configured such that when one end of the flow path 5e communicates with the valve inlet / outlet port 5f, one end of the flow path 6e communicates with the valve inlet / outlet port 6g. It is adjusted so that the flow path 5e and the flow path 6e are positioned at 180 degrees different from each other at the time of rotation so that one end of the flow path 6e and the valve inlet / outlet port 6f communicate with each other when the entrance / exit port 5g communicates. As a result, when both ends of the flow path 5c and the valve inlet / outlet ports 5f and 5g communicate with each other on the gas side rotary valve unit 5 side, both ends of the flow path 6c and the valve inlet / outlet ports 6f and 6g also on the liquid side rotary valve unit 6 side. When one end of the flow path 5e and the valve inlet / outlet port 5f are in communication with each other on the gas side rotary valve unit 5 side, one end of the flow path 6e and the valve inlet / outlet port 6g are connected to each other on the liquid side rotary valve unit 6 side. When one end of the flow path 5e communicates with the valve inlet / outlet port 5g on the gas side rotary valve unit 5 side, one end of the flow path 6e and the valve inlet / outlet port 6f communicate with each other on the liquid side rotary valve unit 6 side. .

  The operation of the external combustion engine 1 will be described with reference to FIG. 3 is an operation diagram of the external combustion engine of FIG. 1, (a) to (c) are processes in which the piston moves downward, (d) is a process in which the piston returns to the reference state, and (e ) To (g) are processes in which the piston moves upward, and (h) is a process in which the piston returns to the reference state. FIGS. 3A to 3H show the operation during one rotation of the rotary valves 5b and 6b, and this operation is repeated every time the rotary valves 5b and 6b rotate.

  As shown in FIGS. 3A to 3H, the flow path 5d of the rotary valve 5b and the connection pipe 7e are always in communication with each other via a valve inlet / outlet port. Therefore, the gas side of the cylinder 4b is always in communication with the flow path 5d of the rotary valve 5b. Further, the flow path 6d of the rotary valve 6b and the connection pipe 7f are always in communication with each other via a valve inlet / outlet port. Therefore, the liquid side of the cylinder 4b is always in communication with the flow path 6d of the rotary valve 6b.

  In FIG. 3A, the flow paths 5c and 5e of the rotary valve 5b do not communicate with any of the connection pipes 7a and 7b, and the flow paths 6c and 6e of the rotary valve 6b communicate with any of the connection pipes 7c and 7d. Not done. At this time, in the evaporator 2, the liquid working medium evaporates and the liquid working medium is vaporized into a high-pressure gas. On the other hand, in the condenser 3, the gaseous working medium is condensed, the working medium becomes a low-pressure gas, and liquefies into a liquid.

  In FIG. 3B, the rotary valve 5b rotates from the state of FIG. 3A, and the flow path 5e of the rotary valve 5b communicates with the connection pipe 7a via the valve inlet / outlet port. Accordingly, the gas side of the evaporator 2 and the gas side of the cylinder 4b are in communication with each other (corresponding to the gas side first communication state). Therefore, the high-pressure gas emitted from the evaporator 2 enters the cylinder 4b through the connection pipe 7a, the flow path 5e, the flow path 5d, and the connection pipe 7e, and pushes the piston 4a downward. At the same time, the rotary valve 6b rotates from the state shown in FIG. 3A, and the flow path 6e of the rotary valve 6b communicates with the connection pipe 7d via the valve inlet / outlet port. Accordingly, the liquid side of the condenser 3 and the liquid side of the cylinder 4b are in communication with each other (corresponding to the liquid side first communication state). Therefore, the piston 4a is pulled downward by the low-pressure gas of the condenser 3 through the liquid working medium passing through the connection pipe 7d, the flow path 6e, the flow path 6d, and the connection pipe 7f.

  In FIG. 3C, the rotary valves 5b and 6b rotate from the state of FIG. 3B, and the flow paths 5c and 5e of the rotary valve 5b are not in communication with any of the connection pipes 7a and 7b. The flow paths 6c and 6e of 6b do not communicate with any of the connecting pipes 7c and 7d. At this time, in the evaporator 2, the liquid working medium is further evaporated, and the liquid working medium is a high-pressure gas. On the other hand, in the condenser 3, the gaseous working medium is further condensed, and the working medium becomes a low-pressure gas, which is liquefied into a liquid. The piston 4a is pushed down.

  In FIG. 3D, the rotary valve 5b rotates from the state of FIG. 3C, and the flow path 5c of the rotary valve 5b communicates with the connection pipe 7a and the connection pipe 7b through the valve inlet / outlet port. Therefore, the gas side of the evaporator 2 and the gas side of the cylinder 4b are in communication with each other, and the gas side of the condenser 3 and the gas side of the cylinder 4b are in communication (corresponding to a third gas-side communication state). . At the same time, the rotary valve 6b rotates from the state of FIG. 3C, and the flow path 6c of the rotary valve 6b communicates with the connection pipe 7c and the connection pipe 7d via the valve inlet / outlet port. Therefore, the liquid side of the evaporator 2 and the liquid side of the cylinder 4b are in communication with each other, and the liquid side of the condenser 3 and the liquid side of the cylinder 4b are in communication (corresponding to a third liquid side communication state). . Therefore, the evaporator 2, the condenser 3 and the piston unit 4 are in pressure equilibrium, and the piston 4a returns to the reference state from below.

  As shown in FIG. 3 (e), the rotary valves 5b and 6b rotate from the state of FIG. 3 (d), and the flow paths 5c and 5e of the rotary valve 5b are not in communication with any of the connecting pipes 7a and 7b. The flow paths 6c and 6e of the rotary valve 6b do not communicate with any of the connection pipes 7c and 7d. At this time, in the evaporator 2, the liquid working medium evaporates, and the liquid working medium is a high-pressure gas. On the other hand, in the condenser 3, the gaseous working medium is condensed, the working medium becomes a low-pressure gas, and liquefies into a liquid.

  As shown in FIG. 3 (f), the rotary valve 5b rotates from the state of FIG. 3 (e), and the flow path 5e of the rotary valve 5b communicates with the connecting pipe 7b via the valve inlet / outlet port. Accordingly, the gas side of the condenser 3 and the gas side of the cylinder 4b are in communication with each other (corresponding to the gas side second communication state). Therefore, the low-pressure gas of the condenser 3 pulls the piston 4a upward via the connection pipe 7b, the flow path 5e, the flow path 5d, and the connection pipe 7e. At the same time, the rotary valve 6b rotates from the state of FIG. 3 (e), and the flow path 6e of the rotary valve 6b communicates with the connection pipe 7c via the valve inlet / outlet port. Accordingly, the liquid side of the evaporator 2 and the liquid side of the cylinder 4b are in communication with each other (corresponding to the liquid side second communication state). Therefore, the piston 4a is pushed upward by the high-pressure gas of the evaporator 2 through the liquid working medium passing through the connection pipe 7c, the flow path 6e, the flow path 6d, and the connection pipe 7f.

  As shown in FIG. 3 (g), the rotary valves 5b and 6b rotate from the state of FIG. 3 (f), and the flow paths 5c and 5e of the rotary valve 5b are not in communication with any of the connecting pipes 7a and 7b. The flow paths 6c and 6e of the rotary valve 6b do not communicate with any of the connection pipes 7c and 7d. At this time, in the evaporator 2, the liquid working medium is further evaporated, and the liquid working medium is a high-pressure gas. On the other hand, in the condenser 3, the gaseous working medium is further condensed, and the working medium becomes a low-pressure gas, which is liquefied into a liquid. The piston 4a is pushed upward.

  As shown in FIG. 3 (h), the rotary valve 5b rotates from the state of FIG. 3 (g), and the flow path 5c of the rotary valve 5b communicates with the connection pipe 7a and the connection pipe 7b via the valve inlet / outlet port. Yes. Therefore, the gas side of the evaporator 2 and the gas side of the cylinder 4b are in communication with each other, and the gas side of the condenser 3 and the gas side of the cylinder 4b are in communication (corresponding to a third gas-side communication state). . At the same time, the rotary valve 6b rotates from the state shown in FIG. 3G, and the flow path 6c of the rotary valve 6b communicates with the connection pipe 7c and the connection pipe 7d via the valve inlet / outlet port. Therefore, the liquid side of the evaporator 2 and the liquid side of the cylinder 4b are in communication with each other, and the liquid side of the condenser 3 and the liquid side of the cylinder 4b are in communication (corresponding to a third liquid side communication state). . Therefore, the evaporator 2, the condenser 3 and the piston unit 4 are in pressure equilibrium, and the piston 4a returns to the reference state from above.

  By repeating the series of operations described above, the piston 4a reciprocates up and down. The reciprocating motion of the piston 4a is extracted as kinetic energy, and the heat energy of the heat source input to the evaporator 2 can be recovered. The frequency of the reciprocating motion of the piston 4a is determined by the number of rotations of the rotary valves 5b and 6b by the motor control of the controller. The higher the rotational speed of the rotary valves 5b, 6b, the higher the frequency of the reciprocating motion of the piston 4a, and more kinetic energy can be extracted from the heat energy of the heat source.

  According to the external combustion engine 1, the gas side and liquid side communication states of the evaporator 2, the condenser 3, and the piston unit 4 are switched synchronously by the gas side rotary valve unit 5 and the liquid side rotary valve unit 6. As a result, the float-type piston 4a can be reciprocated in the vertical direction using the high-pressure gas generated in the evaporator 2 and the low-pressure gas generated in the condenser 3 at the same time, thereby improving the heat energy recovery efficiency of the heat source. Can be made.

  In addition, according to the external combustion engine 1, the rotary valve units 5 and 6 constitute three communication state switching means, so that the three flow paths for switching the communication state in the rotary valves 5b and 6b are provided. Since it can be formed and the communication state can be switched only by rotating the rotary valves 5b and 6b, the apparatus configuration can be reduced in size. Furthermore, since the three communication states can be switched simply by rotating the rotary valves 5b and 6b, the power required for switching can be reduced and the control is easy.

  Further, according to this external combustion engine 1, the frequency of the reciprocating motion of the piston 4a can be controlled by the rotational speed of the rotary valves 5b, 6b, and the output of the external combustion engine (for example, kinetic energy or electrical energy to be recovered). Can be controlled. Furthermore, by controlling the rotational speed of the rotary valves 5b and 6b based on the heat energy (heat input amount) of the recovered heat source, the output of the external combustion engine can be controlled according to the heat energy of the recovered heat source.

  When this external combustion engine 1 is mounted on a vehicle and uses engine cooling water or exhaust gas as a heat source, waste heat of the engine can be recovered with high efficiency, and fuel efficiency can be improved. The external combustion engine 1 is an external combustion engine that is very effective in collecting a low-temperature heat source such as cooling water.

  As mentioned above, although embodiment which concerns on this invention was described, this invention is implemented in various forms, without being limited to the said embodiment.

  For example, in the present embodiment, the configuration in which the external combustion engine is mounted on the vehicle and the waste heat of the engine of the vehicle is recovered is shown as an example, but the configuration of recovering the waste heat of the internal combustion engine other than the vehicle may be used. You may comprise only a combustion engine.

  Further, in this embodiment, the communication state switching means is configured using the rotary valve, but the switching means may be configured in other forms such as switching of the pipeline using the switching valve.

  In the present embodiment, three flow paths are formed in the rotary valve and the three communication states are switched. However, there are various other configurations for the flow path formed in the rotary valve. Applicable. For example, by increasing the number of flow paths in the rotary valve, a configuration in which the three communication states are switched a plurality of times and the piston is reciprocated a plurality of times by one rotation of the rotary valve is also conceivable.

  In this embodiment, a controller is provided and the motor is controlled by the controller to control the rotational speed of the rotary valve (and hence the piston frequency). However, the controller may not be provided. When there is no controller, the motor is turned ON / OFF, and when the motor is ON, the rotary valve is rotated at a constant rotation speed of the molding. In addition, when the switching means is configured other than the rotary valve, an actuator corresponding to the switching means is used.

  DESCRIPTION OF SYMBOLS 1 ... External combustion engine, 2 ... Evaporator, 3 ... Condenser, 4 ... Piston unit, 4a ... Piston, 4b ... Cylinder, 4c ... Spring, 5 ... Gas side rotary valve unit, 5a ... Casing, 5b ... Rotary valve, 5c, 5d, 5e ... flow path, 5f, 5g, 5h ... valve inlet / outlet port, 5i ... rotating shaft, 5j ... pulley, 6 ... liquid side rotary valve unit, 6b ... rotary valve, 6c, 6d, 6e ... flow path, 6f, 6g ... valve inlet / outlet ports, 7a, 7b, 7c, 7d, 7e, 7f ... connecting pipes.

Claims (3)

An evaporator for evaporating a liquid working medium by a heat source;
A condenser for condensing the gaseous working medium;
A piston unit having a piston floating in a liquid working medium and a cylinder arranged in the vertical direction;
A gas side first communication state in which the gas side of the evaporator and the gas side of the cylinder are in communication; a gas side second communication state in which the gas side of the condenser and the gas side of the cylinder are in communication; Gas-side switching means for switching between the gas side and the gas side of the condenser and the gas side third communication state for communicating the gas side of the cylinder and the gas side of the cylinder;
A liquid-side first communication state in which the liquid side of the condenser and the liquid side of the cylinder are in communication; a liquid-side second communication state in which the liquid side of the evaporator and the liquid side of the cylinder are in communication; A liquid side switching means for switching between a liquid side of the condenser and a liquid side of the condenser and a liquid side third communication state communicating the liquid side of the cylinder;
An external combustion engine comprising: The gas side switching means is composed of a gas side rotary valve unit that switches the gas side first to third communication states by rotating a rotary valve in which a plurality of flow paths are formed,
The liquid side switching means includes a liquid side rotary valve unit that switches the liquid side first to third communication states by rotating a rotary valve in which a plurality of flow paths are formed.
2. The external combustion engine according to claim 1, wherein the rotary valve of the gas-side rotary valve unit and the rotary valve of the liquid-side rotary valve unit rotate in synchronism with the same rotational speed.   The external combustion engine according to claim 2, wherein the frequency of the reciprocating motion of the piston is controlled based on the number of rotations of the rotary valve of the gas side rotary valve unit and the rotary valve of the liquid side rotary valve unit.

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