A steam engine in which a liquid and a steam are jetted so that a rotor is turned by the reaction thereof, and the rotor having a well-balanced simple structure. In the steam engine, the rotor 5 having a plurality of bent flow paths 53A to 53D arranged at regular intervals therein is rotatably supported in a closed container 1 filled with the liquid being fitted onto a boss portion 11 of the closed container 1. The boss portion 11 is alternately forming slide-contact portions 11A having a steam feed port and recessed portions 11B. The steam fed into the bent flow path 53 from the steam feed port causes the liquid in the flow path to be jetted outward to rotate the rotor 5. The rotor 5 is of a point-symmetrical shape in cross section free of unbalanced weight, has no moving part, and is simple in structure. When the bent flow path 53 communicates with the recessed portion 11B, the steam remaining in the flow path is cooled and disappears, and the flow path is filled with the liquid.

TECHNICAL FIELD

This invention relates to a steam engine which converts heat energy into mechanical energy such as rotational energy and, particularly, to a steam engine which is capable of efficiently converting heat energy into mechanical energy and is also suited as an engine for mounting on a vehicle.

BACKGROUND ART

Engines (heat engines) that convert heat energy into mechanical energy include internal combustion engines such as gasoline engine and diesel engine, and external combustion engines such as steam engine that executes the so-called Rankine cycle. The internal combustion engine intermittently burns the fuel in the air which is an operation fluid and converts the generated heat into mechanical energy. On the other hand, the steam engine which is an external combustion engine transfers the heat generated by the continuous combustion to the operation fluid offering such advantages that it is easy to control the burning state of the fuel and that harmful exhaust components due to the burning, such as NOx, CO, etc. are formed in small amounts. Besides, the external combustion engine can use not only the heat of combustion but also a variety of kinds of heat sources such as exhausted heat by the internal combustion engine, etc., and has excellent features such as saving energy and also from the standpoint of coping with the environment.

To utilize the above features of the steam engine, study and development have been forwarded to employ the steam engine for vehicles. For instance, JP-A-2002-115506 is disclosing a Rankine cycle unit which actuates the steam engine by using, as a source of heat, the exhausted heat from an internal combustion engine to recover the exhausted heat as mechanical energy. The steam engine unit for executing the Rankine cycle is constituted by a boiler (evaporator) for heating the operation fluid such as water, an expansion machine (steam engine) for generating power by expanding the operation fluid that is heated at a high temperature to have a high pressure, a condenser for cooling and liquefying the operation fluid after it has expanded and a circulating pump for pumping the liquefied operation fluid to the boiler. A turbine is, usually, used as the expansion machine.

The turbine which is a steam engine is a so-called velocity-type engine that utilizes velocity energy, and is equipped with many blades on which the steam of a high speed acts. To efficiently operate the turbine, it is necessary to increase the rotational speed of the turbine so that the peripheral speed of the blades increases to a value that meets the velocity of the steam. Therefore, the turbine becomes a complex engine that operates at high speeds. Besides, the steam engine unit is provided with a boiler, a condenser and the like; i.e., the steam engine unit tends to become a facility which is large in scale.

Under such circumstances, the present applicant has developed a compact steam engine unit that efficiently operates even at low speeds as disclosed in JP-A-2006-329036. According to this steam engine unit as shown inFIG. 4, a rotor103having a bent jet pipe102is rotatably supported in a closed container101filled with the operation fluid in a liquid state. The rotor103is provided with an intake pipe104, and a heating unit105is inserted in a central cylinder at the center of the rotor to thereby constitute a boiler. The operation fluid in the liquid state taken in through the intake pipe104is vaporized in the heating portion105to produce a steam which is jetted from the jet pipe102in a state of being mixed with the liquid to rotate the rotor105clockwise. The jetted steam is guided into a condenser106installed over the closed container101, and is condensed and is refluxed into the closed container101. In order to control the jet and intake of the operation fluid, a jet check valve107and an intake check valve108are disposed at the end portions of the jet pipe102and the intake pipe104, respectively.

In the steam engine ofFIG. 4, the rotor having the jet pipe is provided in the closed container filled with the liquid, the steam of a high pressure vaporized by the heating unit at the center of the rotor is jetted from the jet pipe in the state of a mixture of the liquid and the steam, and the rotational force is obtained by the reaction thereof. The jetted mixture contains much liquid and its mass is far greater than that of the steam. Therefore, the rotational torque of the rotor becomes very larger than that of the case of when the steam only is jetted. Accordingly, a large torque is obtained even when the rotor rotates at low speeds and, hence, the steam engine can be efficiently operated even at low speeds. Besides, the boiler and the condenser are fabricated integrally with the closed container, and the steam engine unit as a whole is compact in size.

DISCLOSURE OF THE INVENTION

Problems that the Invention is to Solve

The steam engine ofFIG. 4developed by the present applicant features excellent efficiency even at low rotational speeds and is compactly constituted. However, the jet pipe and the intake pipe provided in the rotor have different functions, and the jet check valve and the intake check valve are attached to the end portions thereof, respectively. The rotor that is statically or dynamically unbalanced generates vibration when it rotates. By employing the jet pipe and the intake pipe having different functions, however, it is difficult to maintain balance of the rotor by adjusting their weights to be equal to each other. Besides, the jet check valve and the intake check valve attached to the jet pipe and to the intake pipe include moving parts that may become faulty or defective, and require such toils as check and maintenance as well as expenses.

In the steam engine unit, the operation fluid in the liquid state is heated in the boiler and is transformed into the steam which acts on the expansion machine to generate power. Usually, therefore, an extended period of time is required before starting, and follow-up performance to a change in the load becomes inferior to that of internal combustion engines. It is required that the engine mounted on a vehicle has good starting performance and load following capability. To utilize the steam engine unit for the vehicles, therefore, it is desired to improve the starting performance.

The problem according to the invention is to provide an excellently balanced rotor of a very simple constitution for use in a steam engine body that is used as the expansion machine in the steam engine unit in an attempt to improve starting performance and like performances of the steam engine unit.

Means for Solving the Problems

In view of the above problem, the steam engine unit of the invention uses a rotor having a plurality of bent flow paths arranged at regular intervals in a simple structure without unbalanced weight, the rotor being contained and supported in a closed container filled with a liquid so as to be rotated by the steam generated in the boiler while enabling the liquid to be smoothly fed into the flow paths of the rotor. That is, according to the present invention, there is provided “a steam engine unit comprising a closed container filled with a liquid, a rotor dipped in the liquid in the closed container and is rotatably supported therein, and a boiler that heats the liquid in the closed container to generate steam, wherein:

the rotor has an inner circumferential surface formed in a round shape in cross section and a plurality of bent flow paths extending from the inner circumferential surface to an outer circumferential surface, the plurality of bent flow paths being evenly arranged in the circumferential direction of the rotor;

the closed container has a boss portion fixed to the side wall thereof and is protruding into the closed container, and the inner circumferential surface of the rotor is fitted onto the boss portion so that the rotor is rotatably supported thereby; and

the outer circumference of the boss portion alternately forms slide-contact portions on where the inner circumferential surface of the rotor slides in contact therewith, and recessed portions from where the inner circumferential surface of the rotor separates away, the slide-contact portions being provided with a steam feed port for introducing the steam generated in the boiler into the rotor”.

As described in claim2, it is desired that a circulating pump is provided to feed the liquid in the closed container to the boiler, an injection nozzle is provided in the boiler, and the liquid in the closed container is injected in an atomized form into the boiler.

As described in claim3, further, it is desired that a condenser is provided being communicated with the closed container to condense the steam.

Effects of the Invention

The steam engine unit of the invention includes the rotor that is rotatably supported in the closed container filled with the liquid, and wherein the liquid in the plurality of bent flow paths formed in the rotor is jetted from the flow paths in the form of a mixture of the liquid and the steam due to the steam generated in the boiler, and the rotor rotates by the reaction thereof. The jetted mixture contains much liquid and its mass is far greater than that of the steam. Like the steam engine shown inFIG. 4, therefore, a large torque is obtained even at the time when the rotor rotates at low speeds. Therefore, the steam engine body of the invention efficiently operates even at low speeds.

The rotor in the steam engine body of the present invention has the inner circumferential surface formed in a round shape in cross section, and has the plurality of bent flow paths evenly arranged in the circumferential direction of the rotor and extending from the inner circumferential surface to the outer circumferential surface. The rotor has no moving part such as check valve, and features a simple structure and high reliability, and is free from inconvenience that may be caused by the effect of centrifugal force during the rotation. Further, plurality of bent flow paths are evenly arranged in the circumferential direction of the rotor which, therefore, has a point-symmetrical shape in transverse cross section without any unbalanced weight. Therefore, the rotor of the invention has excellent static or dynamic balance.

Moreover, the rotor of the invention is rotatably supported being fitted onto the boss portion that is fixed to the side wall of the closed container, and the outer periphery of the boss portion is alternately forming slide-contact portions on where the inner circumferential surface of the rotor slides in contact therewith and recessed portions from where the inner circumferential surface of the rotor separates away. The slide-contact portions are provided with a steam feed port for introducing the steam generated in the boiler into the rotor. When the bent flow path of the rotor is opened to the steam feed port, the steam flows into the bent flow path and is jetted from the outer periphery of the rotor together with the liquid in the flow path to impart a rotational torque to the rotor.

As the rotor rotates and the communication is interrupted between the bent flow path and the steam feed port, the liquid in the surrounding flows reversely into the bent flow path through the opening on the outer circumferential side of the rotor imparting torque to the rotor in a direction in which the rotational torque increases. Here, the steam remaining in the bent flow path is liquefied upon being cooled by the surrounding liquid of a low temperature. Here, if the cooling is not sufficient, the rotor rotates with the steam remaining therein, and the bent flow path is opened to the steam feed port again. The liquid, therefore, is jetted in decreased amounts and only a decreased rotational torque is produced. According to the present invention, recessed portions are formed in the outer circumference of the boss portion onto which the rotor is fitted and after the communication is interrupted between the bent flow path and the steam feed port accompanying the turn of the rotor, the bent flow path opens in the recessed portion. The liquid of a low temperature is present in the recessed portions and, therefore, the remaining steam is cooled thereby and, besides, the steam partly flows into the recessed portion, and the steam remaining in the bent flow path substantially disappears. As a result, when the bent flow path opens to the steam feed port again, the interior of the flow path has been filled with the liquid, and the steam engine operates efficiently.

The invention of claim2is concerned to the steam engine unit, wherein a circulating pump is provided to feed the liquid in the closed container to the boiler, an injection nozzle is provided in the boiler, and the liquid is injected in an atomized form into the boiler. Usually, the operation fluid is continuously fed in the liquid state into the boiler of the steam engine unit and is transformed into the steam upon being heated. However, a considerable period of time is necessary to evaporate the liquid that is continuously fed, and the starting time is prolonged before power is generated. According to the invention of claim2, the liquid is injected in an atomized form into the boiler from the injection nozzle provided in the boiler, and the time for evaporating the liquid is greatly shortened. Therefore, start performance of the steam engine unit is improved, quick response is attained even when the load has increased, and characteristics required for the vehicle can be satisfied.

The invention of claim3is concerned to the steam engine unit of the present invention, wherein a condenser is provided being communicated with the closed container to condense the steam. The closed container of the present invention is placed in the atmosphere and radiates heat to the surrounding. Therefore, the closed container itself can be used as a so-called low heat source. Upon providing a condenser communicated with the closed container and introducing the steam in the closed container to the condenser, however, the steam can be efficiently condensed and the efficiency of the steam engine unit as a whole can be improved.

DESCRIPTION OF REFERENCE NUMERALS

BEST MODE FOR CARRYING OUT THE INVENTION

An embodiment of the invention will now be described in detail with reference to the drawings.FIG. 1is a view of a whole steam engine unit of the present invention, whereinFIG. 1(a) shows, in transverse section, a steam engine body in the steam engine unit andFIG. 1(b) shows the whole unit inclusive of boiler and the like.FIG. 1(a) is an A-A sectional view ofFIG. 1(b).FIG. 2is a disassembled perspective view showing principal parts of the steam engine body.

The steam engine unit has a closed container1of a round shape in cross section, and contains sealed therein water as a liquid (operation fluid) that is to be heated, the water nearly filling the interior of the closed container1. In this embodiment, a condenser2is provided over the closed container1to condense the steam, and is coupled to the closed container1through a short pipe3. In the short pipe3, a plurality of baffle boards4are attached maintaining a gap preventing water in the liquid state from entering into the condenser2but permitting the condensed water to be refluxed from the condenser2into the closed container1.

In the closed container1of the round shape in cross section, a rotor5is provided being dipped in water. The rotor5has an inner circumferential surface51formed in a round shape in cross section and four bent flow paths53A to53D extending from the inner circumferential surface51to the outer circumferential surface52, the bent flow paths53A to53D being evenly arranged in the circumferential direction of the rotor5maintaining a gap of 90°. In this embodiment, the bent flow paths53are of a shape that becomes narrow toward the outer circumferential surface52. However, the flow paths53may have a same area in cross section over the whole length thereof. The closed container1has a boss portion11that is fixed to the side wall thereof and protrudes into the closed container1. The rotor5has its inner circumferential surface51fitted onto the boss portion11, and is so supported as to rotate in the closed container1.

On the outer circumference of the boss portion11fixed to the side wall of the closed container1as shown inFIGS. 1 and 2, there are alternately formed slide-contact portions11A on which the inner circumferential surface51of the rotor5slides in contact therewith and recessed portions11B separated away from the inner circumferential surface51, the slide-contact portions11A being arc shaped in cross section. A steam introduction passage12is provided in the boss portion11. The steam introduction passage12has a steam inlet12A that is fed with the steam from the boiler6, and steam feed ports12B opened in the slide-contact portions11A to feed steam to the rotor5. At the end portion of the boss portion11on the side opposite to the steam inlet12A, a generator coil13is arranged along the outer circumference thereof, and permanent magnets54are buried in the inner circumferential surface51of the rotor5facing the generator coil13.

By the side of the closed container1, there are disposed a boiler6that heats water in the closed container1to generate the steam, and a circulating pump7for pumping water in the closed container1to the boiler6. The boiler6has an injection nozzle61for injecting water onto the inner wall of the boiler, and water in the closed container1pressurized by the circulating pump7is fed into the boiler6in an atomized form. The boiler6is provided with a heating portion62that burns a fuel. However, the boiler6may be installed, for example, in an exhaust gas passage of an internal combustion engine to generate the steam by utilizing the waste heat of the internal combustion engine. The steam generated in the boiler6is fed to the steam inlet12A of the steam introduction passage12through a pipe passage63.

Next, the operation of the steam engine unit of the invention will be described with reference also toFIG. 3which is a view illustrating the operation of the rotor5.

The water in the closed container1is pumped by the circulating pump7into the boiler6where it is heated and transformed into the steam. The generated steam passes through the pipe passage63and is fed into the steam introduction passage12formed in the boss portion11. The rotor5is rotatably fitted onto the boss portion11, and inner circumferential surface51thereof slides on the slide-contact portions11A on the outer circumference of the boss portion11in contact therewith. The steam feed ports12B of the steam introduction passage12are opened in the slide-contact portions11A. As shown inFIG. 3, if the opening on the side of the inner circumferential surface of the bent flow path which is one of the bent flow paths53formed in the rotor5comes into agreement with the steam feed port12B, the steam flows into the bent flow path53A. The bent flow path53A has been filled with the water in the closed container1, and the steam expands as it passes through the bent flow path53A and is jetted at a high speed in the state of being mixed with water into the closed container1from the end portion of the bent flow path53A opened in the outer circumferential surface52of the rotor5.

A rotational torque acts on the rotor5due to the reaction of the mixture jetted from the end portion of the bent flow path53A, and the rotor rotates counterclockwise inFIG. 3. The jetted mixture contains water which is a liquid in large amounts. Besides, since water has a specific gravity which is very larger than that of the steam, the kinetic amount of the mixture becomes large and a large rotational torque acts on the rotor5. Therefore, a required power can be taken out even when the rotor5rotates at a low speed. The rotational energy (mechanical energy) that accompanies the turn of the rotor5can be taken out to the external unit as electric energy relying on the interacting electromagnetic action of the permanent magnets54turning together with the rotor5and the generating coil13being stationary.

As the rotor5rotates and the communication is interrupted between the opening of the bent flow path53A on the side of the inner circumferential surface and the steam feed port12B, the steam is no longer fed into the bent flow path53A. In this case, water in the closed container1flows reversely into the bent flow path53A through the opening on the side of the outer circumferential surface52, and the steam in the bent flow path53A is cooled by the surrounding water and condenses. The rotor5further rotates and the opening of the bent flow path53A on the side of the inner circumferential surface communicates with the recessed portion11B. Here, water of a low temperature is present in the recessed portion11B, and condensation of the steam remaining in the bent flow path53A is accelerated by the water in the recessed portion11B and, at the same time, part of the steam flows into the recessed portion11B. Therefore, at the time when the bent flow path53A is opened again to the steam feed port12B (steam feed port on the lower side inFIG. 3), the remaining steam is substantially disappearing, and the interior of the bent flow path53A has been filled with the water which is a liquid. Therefore, water is jetted in a decreased amount from the bent flow path53A, and there is no decrease in the produced rotational torque. Further, the water that reversely flows through the bent flow path53A toward the recessed portion11B imparts a torque to the rotor5in the direction in which it rotates to assist the torque produced by the jet of the mixture.

The rotor5of the steam engine body has a plurality of bent flow paths53A to D that are extending from the inner circumferential surface51to the outer circumferential surface52formed in a round shape in cross section, and are evenly arranged in the circumferential direction of the rotor5. The operation of the bent flow path53A is similarly and periodically executed by other bent flow paths, too. The rotor5has no moving part such as check valve and, therefore, has a structure featuring high reliability without inconvenience caused by the centrifugal force of when the rotor rotates. A plurality of the bent flow paths53are evenly arranged in the circumferential direction of the rotor5. Therefore, the rotor5has a point-symmetrical shape in cross section without unbalanced weight, and feature excellent static or dynamic balance as a rotor.

The steam jetted from the rotor5rises through the water, is sent through the short pipe3into the condenser2where it is cooled, condensed and is refluxed into the closed container1. Radiator fins21are provided in the condenser2, and a check valve22and a vacuum pump23are connected to the condenser2to evacuate the air and the like. Therefore, the pressures in the condenser2and in the closed container1are lowered and are maintained at a saturated steam pressure. Radiator fins can be, further, provided on the outer surfaces of the condenser2as represented by two-dot chain lines inFIG. 1(b). In this embodiment, the condenser2is communicated as a separate body with the closed container1. However, it is also allowable to provide radiator fins on the outer surfaces of the closed container1, too, so that the closed container1by itself also works as a condenser.

The water condensed and liquefied in the condenser2refluxes into the closed container1, and is pumped by the circulating pump7from the bottom portion of the closed container1into the boiler6. The pumped water is injected in an atomized form into the boiler from the injection nozzle61disposed in the boiler6, and is heated and quickly evaporated. Therefore, the time for evaporating the water is greatly shortened contributing to improving the starting performance of the steam engine unit and attaining quick response even when, for example, the load has increased.

Field of Utilization in Industry

As described above in detail, the steam engine unit of the invention uses a rotor free of unbalanced weight but having a plurality of bent flow paths arranged at regular intervals, the rotor being contained in the closed container filled with the liquid and rotated by the jet of a mixture of the steam generated in the boiler and the liquid through the bent flow paths, and the rotor being, further, so supported that the liquid is smoothly fed into the flow paths of the rotor. Therefore, the steam engine unit of the invention can be utilized as various power sources, such as an engine mounted on a vehicle. In the above embodiment, the heat from the heating unit is converted into rotational energy which is, further, transformed into electric energy and is taken out. However, it needs not be pointed out that the heat can be taken out as rotational energy by coupling a gear device to the rotor. It will be, further, obvious that the embodiment can be variously modified, such as using a refrigerant like Freon in place of water as a liquid to serve as an operation fluid or suitably changing the sectional shape of the recessed portions in the boss portion.