FLUID MACHINE AND RANKINE CYCLE

TECHNICAL FIELD

The present invention relates to a fluid machine and a Rankine cycle.

BACKGROUND ART

There is known a scroll fluid machine having a shared structure between an expander of a Rankine cycle and a compressor of an air-conditioner (refer to JP 2005-273452A). In this fluid machine, a planetary gear mechanism and a motor/generator are provided between a pulley and the scroll fluid machine, and the fluid machine switches between an expander operation and a compressor operation by switching a rotational speed of the motor/generator.

SUMMARY OF INVENTION

However, in the technique of JP 2005-273452A, the motor/generator is necessary to switch between the expander operation and the compressor operation, so that the configuration becomes complicated.

It is therefore an object of this disclosure to provide a fluid machine capable of switching between an expander operation and a compressor operation with a simple configuration.

According to an aspect of this disclosure, there is provided a fluid machine including: a first shaft that rotates in synchronization with an engine crankshaft; a compressor/expander fluid machine that operates as an expander rotating by converting energy of a refrigerant into mechanical energy in rotation of one direction, and operates as a compressor by compressing and discharging the refrigerant in rotation of the other direction; a planetary gear mechanism having a sun gear connected to the second shaft rotating in synchronization with the compressor/expander fluid machine, a ring gear connected to the first shaft, a plurality of planetary gears that mesh with the ring gear and the sun gear and rotate around the sun gear, and a planetary carrier that supports a rotation shaft of the planetary gear; a first clutch that locks or releases the planetary carrier and one of the ring gear and the sun gear; a second clutch that locks or releases the planetary carrier and a housing; and a clutch control unit that controls locking/releasing of the first and second clutches depending on whether the compressor/expander fluid machine operates as an expander or a compressor.

The foregoing and additional features and characteristics of this disclosure will become more apparent from the following detailed description considered with the reference to the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a skeleton diagram illustrating fluid machine according to a first embodiment;

FIG. 2A is a skeleton diagram illustrating a fluid machine according to the first embodiment when a scroll fluid machine operates as an expander;

FIG. 2B is a skeleton diagram illustrating a fluid machine according to the first embodiment when a scroll fluid machine operates as a compressor;

FIG. 3 is a schematic diagram illustrating operation of the scroll fluid machine;

FIG. 4 is a schematic diagram illustrating a rotational speed of the scroll fluid machine in combination with a locking/releasing state of a pair of clutches and their operation mode;

FIG. 5A is a velocity diagram illustrating operation of a planetary gear mechanism when a first clutch is released, and a second clutch is locked;

FIG. 5B is a velocity diagram illustrating operation of a planetary gear mechanism when the first clutch is locked, and the second clutch is released;

FIG. 5C is a velocity diagram illustrating operation of the planetary gear mechanism when both the clutches are released;

FIG. 6A is a diagram illustrating motions of each element of an actual planetary gear mechanism in connection with FIG. 5A;

FIG. 6B is a diagram illustrating motions of each element of the actual planetary gear mechanism in connection with FIG. 5B;

FIG. 6C is a diagram illustrating motions of each element of the actual planetary gear mechanism in connection with FIG. 5C;

FIG. 7 is a schematic block diagram illustrating the entire system of a Rankine cycle having the fluid machine according to the first embodiment;

FIG. 8A is a schematic block diagram illustrating the entire system of a Rankine cycle when the scroll fluid machine operates as an expander;

FIG. 8B is a schematic block diagram illustrating the entire system of a Rankine cycle when the scroll fluid machine operates as a compressor;

FIG. 9 is a skeleton diagram illustrating a fluid machine according to a second embodiment;

FIG. 10 is a schematic block diagram illustrating the entire system of a Rankine cycle having the fluid machine according to the second embodiment;

FIG. 11 is a skeleton diagram illustrating a fluid machine according to a third embodiment;

FIG. 12 is a schematic plan diagram illustrating the planetary gear mechanism according to the third embodiment;

FIG. 13 is a skeleton diagram illustrating a fluid machine according to a fourth embodiment;

FIG. 14A is a skeleton diagram illustrating the fluid machine according to the fourth embodiment when the scroll fluid machine operates as an expander; and

FIG. 14B is a skeleton diagram illustrating the fluid machine according to the fourth embodiment when the scroll fluid machine operates as a compressor.

DESCRIPTION OF EMBODIMENTS
First Embodiment

FIG. 1 is a skeleton diagram illustrating a fluid machine 1 according to a first embodiment. FIG. 2A is a skeleton diagram when a scroll fluid machine 11 operates as an expander, and FIG. 2B is a skeleton diagram when the scroll fluid machine 11 operates as a compressor.

The fluid machine 1 according to the first embodiment includes a scroll fluid machine 11, a planetary gear 31, a pair of clutches 41 and 42, and a pulley 51 (first shaft).

First, an overview of the scroll fluid machine 11 will be described with reference to FIG. 3. FIG. 3 is a schematic diagram illustrating operation of the scroll fluid machine. Referring to FIG. 3, the scroll fluid machine 11 includes a cylindrical casing 12, a fixed scroll 13, and a movable scroll 14.

The fixed scroll 13 has a plate-like board portion (not illustrated) and a tooth portion 13a protruding to the movable scroll 14 side from the board portion. The movable scroll 14 also has a plate-like board portion (not illustrated) and a tooth portion 14a protruding to the fixed scroll 13 side from the board portion. The tooth portions 13a and 14a of the scrolls 13 and 14, respectively, is formed in a spiral shape rotating counterclockwise such that a radius of curvature increases slowly from one end, and a pair of tooth portions 13a and 14a are combined to have the same spiral winding direction. In this case, the tooth portions 13a and 14a make line contact in a plurality of places to form an enclosed space (working chamber) between a pair of the neighboring line contacts.

The fixed scroll 13 is fixed to the cylindrical casing 12. The movable scroll 14 is revolved with respect to an axis decentered from the rotation shaft 21 (second shaft, refer to FIG. 1) located on the center of the cylindrical casing 12. If the movable scroll 14 is revolved in one direction (either of clockwise or counterclockwise in FIG. 3), the line contact position of a pair of the tooth portions 13a and 14a moves slowly in the same direction while a fluid is enclosed in the enclosed space (working chamber) formed between a pair of the neighboring line contacts. For this reason, for example, when the movable scroll 14 is revolved counterclockwise (forward rotation) in FIG. 3, a volume of the enclosed space formed between a pair of the neighboring line contacts increases slowly. In comparison, when the movable scroll 14 is revolved clockwise (reverse rotation) in FIG. 3, the enclosed space formed between a pair of the neighboring line contacts is reduced slowly.

In the leftmost diagram of FIG. 3, out of states of the enclosed space formed between a pair of the neighboring line contacts, a smallest state of the pair of enclosed spaces 15 is formed in the center. Focusing on this pair of enclosed spaces 15, as the movable scroll 14 is revolved forward, the pair of the enclosed spaces are enlarged slowly as a pair of the enclosed spaces 16 and 17 as illustrated in the second and third diagrams from the left side of FIG. 3, and positions thereof are deviated toward the outer circumference. In the rightmost diagram of FIG. 3, the pair of enclosed spaces 18 having the largest state are formed in the outermost circumference side. In practice, there are other pairs of enclosed spaces formed between a pair of the neighboring line contacts as well, and a similar change is generated in other enclosed spaces.

Meanwhile, in a different way, a pair of the largest enclosed spaces 18 out of the enclosed spaces formed between a pair of the neighboring line contacts are formed in the outermost circumference as illustrated in the rightmost side of FIG. 3. Focusing on this pair of enclosed spaces 18, as the movable scroll 14 is reversely revolved, the pair of enclosed spaces are reduced slowly as a pair of enclosed spaces 17 and 16, and their positions are deviated into the inner circumference as illustrated in the second and third diagrams from the right side of FIG. 3. In addition, in the leftmost diagram of FIG. 3, a pair of the smallest enclosed spaces 15 are formed in the center. In practice, there are other pairs of enclosed spaces formed between a pair of the neighboring line contacts as well, and a similar change is generated in other enclosed spaces.

Using such a characteristic caused by the revolution of the movable scroll 14, the scroll fluid machine 11 can operate as an expander in the case of the forward rotation and can be operated as a compressor in the case of the reverse rotation. The movable scroll 14 has a rotation shaft 21.

In order to allow a fluid (refrigerant) for actuating the scroll fluid machine 11 to access the scroll fluid machine 11, the casing 12 is provided with a first access port 22 (refer to FIG. 1) that allows the fluid to access the pair of the smallest enclosed spaces 15 illustrated in the leftmost side of FIG. 3. In addition, the casing 12 is provided with a second access port 23 (refer to FIG. 1) for allowing the fluid to access the pair of largest enclosed spaces 18 illustrated in the rightmost side of FIG. 3.

When the scroll fluid machine 11 operates as an expander, a high-pressure/high-temperature refrigerant gas (fluid) is introduced from the first access port 22 as illustrated in FIG. 2A. The high-pressure/high-temperature refrigerant gas introduced from the first access port 22 to the enclosed space 15 drives the movable scroll 14 with an inflating pressure (the rotation shaft 21 rotates forwardly). As the enclosed space is enlarged, the refrigerant inside the enclosed space 15 weakens a force of driving the movable scroll 14 (refer to a state change indicated by the right direction of FIG. 3). As the movable scroll 14 finally arrives at the outer circumference, the refrigerant gas is discharged to the outside of the second access hole 23 as illustrated in FIG. 2A. The movable scroll 14 is continuously driven by consecutively introducing the high-temperature/high-pressure refrigerant gas from the first access hole 22 (the rotation shaft 21 continuously rotates forwardly). As a result, the heat energy of the high-temperature/high-pressure refrigerant gas (fluid) can be converted into rotational energy (mechanical energy).

Meanwhile, when the scroll fluid machine 11 operates as a compressor, the rotation shaft 21 of the scroll fluid machine 11 rotates (reversely) by virtue of external power, and the refrigerant gas is introduced from the second access hole 23 as illustrated in FIG. 2B. The refrigerant gas introduced into the enclosed space 18 from the second access hole 23 is compressed as the enclosed space is reduced (refer to a state change of the left direction illustrated in FIG. 3). As the movable scroll 14 arrives at the center, the refrigerant gas having a higher temperature and a higher pressure than those of the atmosphere is discharged into the outside from the first access hole 22 as illustrated in FIG. 2B. By continuously performing the reverse rotation of the rotation shaft 21 of the scroll fluid machine 11 to continuously introduce the refrigerant gas from the second access hole 23, the refrigerant gas having a higher temperature and a higher pressure than those of the atmosphere may be continuously discharged from the first access hole 22.

Here, a fluid machine capable of operating as an expander by converting energy of the fluid into mechanical energy in the case of rotation in one direction and operating as a compressor by compressing and discharging the fluid in the case of rotation in the other direction is defined as a “compressor/expander fluid machine.” Although the scroll fluid machine 11 is exemplified as the compressor/expander fluid machine in the first embodiment, the invention is not limited thereto. Without limiting to the scroll type, any positive displacement type fluid machine, such as a piston type or a vane type, may be used as the compressor/expander fluid machine if the enclosed space is enlarged in the case of rotation of one direction and is reduced in the case of reverse rotation of the other direction. Therefore, other types of the fluid machines may be used instead of the scroll fluid machine 11.

Alternatively, a fluid machine that operates as a motor that rotates by converting energy of a fluid into mechanical energy in the case of rotation in one direction and operates as a pump that compresses and discharges a fluid in the case of rotation of the other direction may be defined as a “pump/motor fluid machine.” In this definition, the aforementioned scroll fluid machine 11 is a pump/motor fluid machine. That is, the pump/motor fluid machine may be used instead of the compressor/expander fluid machine.

Returning to FIG. 1, when the scroll fluid machine 11 operates as an expander, it is necessary to rotate the shaft 21 forwardly. When the scroll fluid machine 11 operates as a compressor, it is necessary to rotate the rotation shaft 21 reversely. For this reason, a technique of the related art has been discussed, in which the scroll fluid machine switches between the expander operation and the compressor operation of the scroll fluid machine by switching the rotational speed of the motor/generator.

However, in the technique of the related art, a motor/generator is necessary to switch between the expander operation and the compressor operation, and the configuration thereof is complicated accordingly.

In the technique of the related art, the motor/generator operates as a generator when the scroll fluid machine operates as an expander. In this case, since the rotation of the scroll fluid machine is transmitted to the motor/generator in an accelerated manner, the motor/generator (generator) rotates fast (for example, 10,000 rpm). As the motor/generator rotates fast, friction increases. Therefore, recovery efficiency is degraded, and a fuel efficiency improvement range is reduced.

In the technique of the related art, most of the mechanical energy (kinetic power) obtained by operating the scroll fluid machine as an expander is recovered as electric power and is stored in a battery. For this reason, if rotation of an engine is assisted using kinetic power, the kinetic power obtained by the scroll fluid machine is converted into electric power using the motor/generator, and the converted electric power is re-converted into kinetic power. That is, since a loss caused by the conversion is significant, the fuel efficiency improvement range using kinetic power assist is reduced. Furthermore, when the motor/generator is used, electric circuitry such as an inverter is necessary, which increases cost, and a large-capacity battery is necessary to store the recovered electric power. As a result, the technique of the related art is only applicable to a hybrid vehicle in reality and has limited compatibility.

In this regard, the inventors of this disclosure studied whether or not the operation of the scroll fluid machine can switch between a compressor operation and an expander operation without using a motor/generator. That is, using a planetary gear mechanism 31 and a pair of clutches 41 and 42 as a control element, the operation of the scroll fluid machine switches between the expander operation and the compressor operation.

According to this disclosure, the engine rotation is assisted by directly transmitting, to the engine, mechanical energy (kinetic power) obtained by operating the scroll fluid machine 11 as an expander. Specifically, a belt drive unit is configured such that a belt 55 is looped and driven between a pulley 51 and a crank pulley 54 of the engine 53 to rotate the pulley 51 and the engine crankshaft in synchronization. It is noted that this disclosure is not limited to a pulley/belt transmission unit, but may be applicable to a chain transmission unit or a gear transmission unit as well.

The planetary gear mechanism 31 includes a sun gear 32, a ring gear 33, a plurality of planetary gears 34 that mesh with both the sun gear 32 and the ring gear 33 and surrounds the sun gear 32, and a planetary carrier 35 for fixing the shafts of the planetary gears 34.

The rotation shaft 52 of the pulley 51 is connected to the ring gear 33, and the rotation shaft 21 of the scroll fluid machine 11 is connected to the shaft of the sun gear 32. A first clutch 41 is provided between the planetary carrier 35 and the ring gear 33 to engage/release the planetary carrier 35 and the ring gear 33. A second clutch 42 is provided between the planetary carrier 35 and the housing 36 to engage/release the planetary carrier 35 and the housing 36. The arrangement of the first clutch 41 is not limited thereto. Alternatively, a first clutch 41′ may be provided between the planetary carrier 35 and the sun gear 32 (refer to the dotted line in FIG. 1).

FIG. 4 is a table showing a rotational speed of the scroll fluid machine 11 in combination with the locking/releasing states of a pair of clutches 41 and 42 and their operation mode when a rotational speed of the pulley 52 is set to 1000 rpm. FIGS. 5A to 5C are velocity diagrams illustrating the operation of the planetary gear mechanism 31. FIGS. 6A to 6C are diagrams illustrating motions of each element of an actual planetary gear mechanism 31 to match FIGS. 5A to 5C, respectively.

It is noted that a gear ratio between the ring gear 33 and the sun gear 32 is set to 2:1 in FIGS. 4, 5A to 5C, and 6A to 6C. Such a gear ratio between the ring gear 33 and the sun gear 32 is set based on the following reasons. Specifically, a value of the refrigerant volume flow rate necessary to operate the scroll fluid machine 11 as an expander and a value of the refrigerant volume flow rate necessary to operate the scroll fluid machine 11 as a compressor were examined. A ratio between both the values was 1:2. For this reason, it is necessary to increase a rotational speed twice in the compressor operation, compared to the expander operation. Typically, it is known that the necessary value of the refrigerant volume flow rate in the compressor operation is higher than that of the expander operation.

FIG. 5A is a velocity diagram when the first clutch 41 is released, and the second clutch 42 is locked. In this state, the pulley 51 is driven by virtue of the power of the engine 53. Since the planetary carrier 35 is connected to the housing 36 as the second clutch 42 is locked (refer to FIG. 2A), a rotational speed of the planetary carrier 35 becomes zero rpm. For convenient description purposes, it is assumed that the pulley 51 rotates at a rotational speed of 1000 rpm in synchronization with the engine rotation. In this case, the rotational speed of the sun gear 32 is accelerated to −2000 rpm due to a reduction gear ratio. The sign in front of “2000 rpm” means that the sun gear 33 rotates reversely to the rotational direction of the pulley 51.

FIG. 5B is a velocity diagram when the first clutch 41 is locked, and the second clutch 42 is released. It is noted that the rotational speed of the pulley 51 is assumed to 1000 rpm for comparison with FIG. 5A. Since the planetary carrier 35 is connected to the ring gear 33 as the first clutch 41 is locked (refer to FIG. 2B), the ring gear 33 and the planetary carrier 35 have the same rotational speed of 1000 rpm. For this reason, the sun gear 32 also has the same rotational speed of 1000 rpm. In other words, the pulley 51 and the rotation shaft 21 of the scroll fluid machine 11 are coupled in a direct linkage state.

FIG. 5C is a velocity diagram when both the clutches 41 and 42 are released. It is noted that the rotational speed of the pulley 51 is assumed to 1000 rpm for comparison with FIGS. 5A and 5B. In this state, it is possible to remove torque transmission between the pulley 51 and the rotation shaft 21 of the scroll fluid machine 11. It is noted that, since the rotational speed of the sun gear 33 becomes zero rpm, the planetary carrier 35 rotates at a rotational speed corresponding to a point where a line between the zero rpm point of the sun gear 33 and the 1000 rpm point of the pulley 51 intersects with a vertical line of the planetary carrier 35.

While the pulley 51 is a drive side in FIG. 5A, the scroll fluid machine 11 is a drive side in FIG. 5B. That is, it is recognized that, if the scroll fluid machine 11 operates as an expander in the state of FIG. 5B, and the rotation shaft 21 rotates forward at a rotational speed of 1,000 rpm, it is possible to rotate the pulley 51 at the same rotational speed of 1,000 rpm. In this manner, the fluid energy is converted into the rotational energy using the scroll fluid machine 11, and the converted rotational energy is used to assist rotation of the engine 53. Meanwhile, it is recognized that, if the pulley 51 rotates forward at a rotational speed of 1000 rpm by driving the engine from the state of FIG. 5A, it is possible to rotate the rotation shaft 21 reversely at a rotational speed of 2,000 rpm and use the scroll fluid machine 11 as a compressor.

As described above, according to this embodiment, a gear ratio between the ring gear 33 and the sun gear 32 is set to twice. However, the invention is not limited thereto. Instead, the gear tooth ratio between the ring gear 33 and the sun gear 32 may be set to 1.5 to 4. This will be described below.

Comparison will be made between vehicles having large and small sizes (or engine displacement). An air-conditioning capability does not change significantly if the number of persons in a vehicle is the same. Therefore, a require value of the refrigerant flow rate of the compressor does not change significantly between vehicles having large and small sizes, but the waste heat amount increases for a vehicle having the larger size. Therefore, in order to increase a waste heat recovery amount, a required value of the refrigerant flow rate of the expander increases in a vehicle having a large size, compared to vehicle having a small size. If (a rating of) the compressor/expander fluid machine is upgraded as the size of the vehicle increases, the gear ratio is reduced relatively because it is not necessary to increase a rotational speed of the compressor in the vehicle having a large size accordingly. Meanwhile, it is necessary to relatively increase a rotational speed of the compressor in the vehicle having a small size, and the gear ratio is set to be relatively higher. Through a study for a gear ratio range in consideration of a size of a vehicle, that is, a practical engine displacement and a rating of the compressor/expander fluid machine in a practical case, it was recognized that a suitable gear ratio range is 1.5 to 4.

FIG. 7 is a schematic block diagram illustrating the entire system of a Rankine cycle 61 having the fluid machine 1 according to this embodiment. FIG. 8A is a schematic block diagram illustrating the entire system of the Rankine cycle 61 when the scroll fluid machine 11 operates as an expander. FIG. 8B is a schematic block diagram illustrating the entire system of the Rankine cycle 61 when the scroll fluid machine operates as a compressor. The Rankine cycle 61 has a refrigerant pump 62, a vaporizer 63, a scroll fluid machine 11 as an expander, and a condenser 64. Each element is connected to each other by the refrigerant path 71 to 74 where the refrigerant such as R134a is circulated.

A shaft of the refrigerant pump 62 is integrated with the rotation shaft 52 of the pulley 51 (refer to FIG. 1). Therefore, the refrigerant pump 62 is driven by the output power (kinetic power) generated from the scroll fluid machine 11, and the generated kinetic power is transmitted to the engine 53 through the belt drive unit 51, 55, and 54 to assist rotation of the engine 53.

The refrigerant from the refrigerant pump 62 is supplied to the vaporizer 63 through the refrigerant path 71. The vaporizer 63 is a heat exchanger that performs heat exchange between a high temperature medium and the refrigerant from the refrigerant pump 62 to evaporate and heat the refrigerant. The high temperature medium may include an engine coolant.

The refrigerant from the vaporizer 63 is supplied to the scroll fluid machine 11 as an expander through the refrigerant path 72. The scroll fluid machine 11 as an expander converts heat into rotational energy by inflating the evaporated and heated refrigerant. The kinetic power recovered to the scroll fluid machine 11 as an expander drives the refrigerant pump 62 and is transmitted to the engine 53 through the belt drive unit to assist rotation of the engine 53.

The refrigerant from the scroll fluid machine 11 as an expander is supplied to the condenser 64 through the refrigerant path 73. The condenser 64 is a heat exchanger that performs heat exchange between the external air and the refrigerant to cool and liquefy the refrigerant. For this reason, the condenser 64 is cooled using a fan 65.

The refrigerant liquefied by the condenser 64 is returned to the refrigerant pump 62 through the refrigerant path 74. The refrigerant returned to the refrigerant pump 62 is sent to the vaporizer 63 again using the refrigerant pump 62 and circulates around each element of the Rankine cycle 61.

In this manner, it is possible to operate the scroll fluid machine 11 as an expander.

Next, a description will be made for a refrigeration cycle 80. The refrigeration cycle 80 is combined with the Rankine cycle 61 in order to share the refrigerant circulating through the Rankine cycle 61. The refrigeration cycle 80 has a scroll fluid machine 11 as a compressor, a condenser 64, and an evaporator 82.

A first bypass path 81 that branches from the refrigerant path 74 and merges to the refrigerant path 73 is inserted into the evaporator 82. In addition, a second bypass path 87 that branches from the refrigerant path 72 and merges to the refrigerant path 73 in the downstream side from the merging portion 85 of the first bypass path 81 is provided.

The scroll fluid machine 11 as a compressor is driven by the engine to compress the refrigerant to make a high-temperature/high-pressure refrigerant gas. That is, a driving force of the engine is transmitted to the rotation shaft 21 through the belt drive unit 54, 55, and 51 to drive the scroll fluid machine 11.

The refrigerant from the scroll fluid machine 11 serving as a compressor merges into the refrigerant path 73 through the second bypass path 87 and is supplied to the condenser 64. The condenser 64 is a heat exchanger that performs heat exchanger with the external air to condense and liquefy the refrigerant.

The liquid refrigerant from the condenser 64 is supplied to the evaporator 82 through the first bypass path 81 branching from the refrigerant path 74. The evaporator 82 is disposed inside the casing of the air-conditioner unit along with a heater core (not illustrated). The evaporator 82 is a heat exchanger that evaporates the liquid refrigerant from the condenser 64 and cools the conditioning air from a blower fan using latent heat of this evaporation.

The refrigerant evaporated by the evaporator 82 is returned to the scroll fluid machine 11 serving as a compressor through the refrigerant path 73. It is noted that a mixing ratio between the conditioning air cooled by the evaporator 82 and the conditioning air heated by the heater core is changed depending on an opening level of an air mixing door, so that a temperature is adjusted to a value set by a user.

The merging portion of the second bypass path 87 is provided with a three-way valve 88 having three ports A, B, and C. The three-way valve 88 is a valve for switching the fluid path. For example, in a valve close state of the three-way valve 88, the ports A and B are connected, and the ports A and C are disconnected. Meanwhile, in a valve open state, the ports A and B are disconnected, and the ports A and C are connected.

When the scroll fluid machine 11 operates as an expander, it is necessary to circulate the refrigerant as indicated by the arrow of FIG. 8A. For this reason, a check valve 89 for preventing a reverse flow of the refrigerant in the refrigerant path 73 from the merging portion 85 to the first bypass path 81 is provided in the first bypass path 81.

Meanwhile, when the scroll fluid machine 11 operates as a compressor, it is necessary to circulate the refrigerant as indicated by the arrow of FIG. 8B. For this reason, a switch valve 90 for opening or closing the refrigerant path 74 is provided in the refrigerant path 74. When the scroll fluid machine 11 operates as a compressor, the switch valve 90 is fully closed, so that a liquid refrigerant from the condenser 64 is guided to the evaporator 82. When the scroll fluid machine 11 operates as an expander, the switch valve 90 is fully opened, so that the liquid refrigerant from the condenser 64 is guided to the refrigerant pump 62.

When the scroll fluid machine 11 operates as a compressor, a check valve 91 for preventing a backflow of the refrigerant from the scroll fluid machine 11 to the vaporizer 63 is provided in the refrigerant path 72.

The engine controller 95 (clutch control unit) controls the three-way valve 88, the switch valve 90, a pair of the clutches 41 and 42, and the three-way valve 88. Since a driving range for driving the Rankine cycle 61 is determined in advance, the engine controller 95 determines whether or not a driving condition is within the Rankine cycle driving range. If the driving condition is within the Rankine cycle driving range, it is determined that the scroll fluid machine 11 operates as an expander. In this case, an instruction is made such that the switch valve 90 has a full open state, the first clutch 41 is released, and the second clutch 42 is locked. The three-way valve 88 is not turned on.

The engine controller 95 monitors whether or not there is an air-conditioning request. If there is an air-conditioning request, and the refrigerant from the evaporator 82 has a temperature exceeding an upper limitation temperature, it is determined that the scroll fluid machine 11 operates as a compressor. In this case, an instruction is made such that the switch valve 90 has a full closed state, the first clutch 41 is locked, and the second clutch 42 is released. The three-way valve 88 is turned on.

Here, the functional effects of this embodiment will be described.

A fluid machine according to this embodiment includes: a pulley 51 (first shaft) that rotates in synchronization with the crankshaft of the engine 53; a scroll fluid machine 11 (compressor/expander fluid machine) that operates as an expander by converting energy of the refrigerant (fluid) into mechanical energy when it rotates in one direction or operates as a compressor by compressing the refrigerant (fluid) when it rotates in the other direction; a planetary gear mechanism 31 having a sun gear 32 connected to the shaft 21 of the scroll fluid machine 11 (second shaft rotating in synchronization with the compressor/expander fluid machine), a ring gear 33 connected to the pulley 51, a plurality of planetary gears 34 rotating around the sun gear 32 by meshing with the ring gear 33 and the sun gear 32, and a planetary carrier 35 that supports the rotation shaft of the planetary gear 34; a first clutch 41 that locks or releases the planetary carrier 35 and the ring gear 33; and a second clutch 42 that locks or releases the planetary carrier 35 and the housing 36. According to this embodiment, unlike the technique of the related art, it is possible to switch between the expander operation and the compressor operation with a simple structure without a motor/generator.

In the related art, most of the mechanical energy (kinetic power) obtained in the expander operation is recovered as electric power. However, according to this embodiment, the mechanical energy is directly transmitted to the engine through the belt drive unit 51, 55, and 54 without conversion to the electric power to assist engine rotation. According to this embodiment, unlike the apparatus of the related art, a loss is not generated in conversion from electric power to kinetic power, and the kinetic power can be transmitted in a mechanical energy state, so that it is possible to obtain excellent efficiency. Unlike the technique of the related art, it is possible to obtain excellent fuel efficiency even at the same expander output. Since the mechanical energy is not recovered as electric power, a high capacity battery is not necessary. This embodiment may also be applicable to various types of devices without limiting to a hybrid vehicle.

According to this embodiment, when the scroll fluid machine 11 (compressor/expander fluid machine) operates as an expander, the engine controller 95 (clutch control unit) performs control such that the first clutch 41 is locked, and the second clutch 42 is released. Therefore, as the planetary carrier 35 and the ring gear 33 rotate in synchronization, it is possible to rotate the pulley 51 and the scroll fluid machine 11 in the same direction. That is, in the technique of the related, the motor/generator (generator) rotates at a high speed when the scroll fluid machine 11 operates as an expander. However, according to this embodiment, since the second clutch 42 is locked, the ring gear 33 is integrated with the planetary carrier 35. Therefore, in the configuration of this embodiment, since there is no portion that rotates at a high speed carelessly, it is possible to prevent degradation of efficiency caused by the high speed rotation.

According to this embodiment, when the scroll fluid machine 11 (compressor/expander fluid machine) operates as a compressor, the engine controller 95 (clutch control unit) performs control such that the first clutch 41 is released, and the second clutch 42 is locked. Therefore, since rotation of the planetary carrier 35 stops, it is possible to rotate the pulley 51 and the scroll fluid machine 11 reversely to each other.

According to this embodiment, the gear ratio between the ring gear 33 and the sun gear 32 is set to 1.5 to 4. Therefore, it is possible to set the gear ratio to match a practical engine displacement.

According to this embodiment, a gear ratio between the ring gear 33 and the sun gear 32 (number of ring gear teeth/number of sun gear teeth) is set to match a ratio between the refrigerant volume flow rate necessary in the expander when the scroll fluid machine 11 (compressor/expander fluid machine) operates as an expander and a refrigerant volume flow rate necessary in the compressor when the scroll fluid machine 11 operates as a compressor. As a result, it is possible to satisfy both the refrigerant volume flow rate necessary in the expander and the refrigerant volume flow rate necessary in the compressor.

Second Embodiment

FIG. 9 is a skeleton diagram illustrating a fluid machine 1 according to a second embodiment, and FIG. 10 is a schematic block diagram illustrating the entire system of a Rankine cycle 61 having the fluid machine 1 according to the second embodiment, in which like reference numerals denote like elements as in FIGS. 1 and 7 of the first embodiment.

According to the first embodiment, the shaft of the refrigerant pump 62 is integrated with the rotation shaft 52 of the pulley 51 (refer to FIG. 1). For this reason, the refrigerant pump 62 is driven when the scroll fluid machine 11 operates as both the expander and the compressor. However, as recognized from FIG. 8B, when the scroll fluid machine 11 operates as a compressor, it is not necessary to operate the refrigerant pump 62 in practice. If the refrigerant pump 62 is driven unnecessarily when the scroll fluid machine 11 is driven using the engine power, the engine power is consumed uselessly.

In this regard, according to the second embodiment, the refrigerant pump 62 is driven when the scroll fluid machine 11 operates as an expander, and the refrigerant pump 62 stops when the scroll fluid machine 11 operates as a compressor. For this reason, according to the second embodiment, a gear 101 is provided in the rotation shaft 35a of the planetary carrier 35. The gear 101 operates in synchronization with the planetary carrier 35. In addition, in order to drive the refrigerant pump 62, the gear 101 meshes with a gear 102 for driving the refrigerant pump 62. The refrigerant pump 62 may include, for example, a gear type pump.

As a result, when the scroll fluid machine 11 operates as an expander, the first clutch 41 is locked. Therefore, the planetary carrier 35 rotates along with the pulley 51 at a rotation speed ratio of 1:1 (refer to FIG. 5B). As the planetary carrier 35 rotates, the refrigerant pump 62 is driven by the gear 101 driven in synchronization with the planetary carrier 35 and the gear 102 meshing with the gear 101. That is, when the scroll fluid machine 11 operates as an expander, the refrigerant pump 62 is driven.

Meanwhile, when the scroll fluid machine 11 operates as a compressor, the second clutch 42 is locked. Therefore, the planetary carrier 35 does not rotate (refer to FIG. 5A). If the planetary carrier 35 does not rotate, the gears 101 and 102 do not rotate, and the refrigerant pump 62 is not driven. That is, when the scroll fluid machine 11 operates as a compressor, the refrigerant pump 62 is not driven.

In this manner, the Rankine cycle according to the second embodiment includes, in addition to the fluid machine 1 according to the first embodiment, a refrigerant pump 62 that supplies a liquid refrigerant; an vaporizer 63 that heats and vaporizes the liquid refrigerant supplied from the refrigerant pump 62; an expander that rotates by converting energy of the refrigerant vaporized in the vaporizer 63 into mechanical energy; and a condenser 64 that condenses the refrigerant discharged from the expander to recover it to a liquid refrigerant. In this Rankine cycle, the refrigerant pump 62 is driven by the rotation shaft of the planetary carrier 35 of the fluid machine 1, and the expander is a compressor/expander fluid machine 11 of the fluid machine 1. As a result, the refrigerant pump 62 is driven only when the Rankine cycle 61 operates. Therefore, it is possible to suppress useless consumption of the engine power caused by driving the refrigerant pump 62 even when the Rankine cycle 61 is not operated.

Third Embodiment

FIG. 11 is a skeleton diagram illustrating a fluid machine 1 according to a third embodiment, and FIG. 12 is a schematic plan diagram illustrating a planetary gear mechanism 31 according to the third embodiment, in which like reference numerals denote like elements as in FIG. 9 of the second embodiment.

The third embodiment is based on the configuration of the second embodiment. Specifically, according to the third embodiment, the refrigerant pump 62 is driven when the scroll fluid machine 11 operates as an expander, and the refrigerant pump 62 stops when the scroll fluid machine 11 operates as a compressor. In addition, according to the third embodiment, a freewheel clutch 113 is provided in all of the planetary gears 34 in the planetary gear mechanism 31, and the first clutch 41 is removed.

Typically, the freewheel clutch 113 is provided in all of three planetary gears 34. However, in some cases, the freewheel clutch 113 may be omitted partially and may be provided in one of the planetary gears. In this case, as illustrated in FIG. 12, one of the planetary gears 34 (upper gear in FIG. 12) includes a rotation shaft 111 and an external teeth gear 112 rotatable independently from the rotation shaft 111 and concentrically with the rotation shaft 111. In addition, the freewheel clutch 113 is interposed between the inner circumference of the external teeth gear 112 and the outer circumference of the rotation shaft 111. It is noted that, although the freewheel clutch 113 is provided in the upper planetary gear 34 in FIG. 12, the invention is not limited thereto. That is, the freewheel clutch 113 may be provided in the lower left or lower right planetary gear 34.

The freewheel clutch 113 includes a housing 114, a ball 115, a spring 116, and a spring retainer 117. The housing 114 is formed in an arc shape having a thickness in a radial direction. The outer circumference 114a of the housing 114 is fixed to the inner circumference of the external teeth gear 112, and the inner circumference 114b of the housing 114 is slidable along the outer circumference 111a of the rotation shaft 11. The housing 114 has a pair of hollows in the inner circumferential side. Each of the hollows houses a ball 115, a spring 116 that biases the ball 115 in one circumferential direction (counterclockwise in FIG. 12), and a spring retainer 114 that retains the spring 116.

In FIG. 12, when the sun gear 32 rotates counterclockwise, the external teeth gear 112 meshing with the sun gear 32 rotates clockwise along with the freewheel clutch 113. In this case, the ball 115 is inserted between the housing 114 and the rotation shaft 111 to engage (or lock) both the housing 114 and the rotation shaft 111. As the freewheel clutch 113 is locked, the external teeth gear 112 and the rotation shaft 111 moves in synchronization. For this reason, the planetary carrier 35 rotates counterclockwise, and the ring gear 33 also rotates counterclockwise. That is, as illustrated in FIG. 5B, the sun gear 32, the planetary carrier 35, and the ring gear 33 rotate in synchronization. When the freewheel clutch 113 is locked, the same function is generated as in the case where the first clutch 41 is locked in the second embodiment. That is, the scroll fluid machine 11 operates as an expander.

Meanwhile, when the sun gear 32 rotates clockwise, the ball 115 of the freewheel clutch 113 compresses the spring 116 resisting to a biasing force of the spring 116. In this case, the ball 115 does not engage (lock) the housing 114 and the rotation shaft 111. For this reason, rotation of the external teeth gear 112 is not transmitted to the rotation shaft 111, and the planetary carrier 35 does not rotate. That is, as illustrated in FIG. 5A, the planetary carrier 35 does not rotate even when the sun gear 32 rotates. When the freewheel clutch 113 is not locked, the same function is generated as in the case where the first clutch 41 of the second embodiment is released. That is, the scroll fluid machine 11 operates as a compressor.

In this manner, since the freewheel clutch 113 serves as the first clutch 41 of the second embodiment, the first clutch is replaced with the freewheel clutch 113 as illustrated in FIG. 11 according to the third embodiment.

According to the third embodiment, the first clutch 41 of the first embodiment is replaced with the freewheel clutch 113 that fixes the planetary carrier 35 and one of the ring gear 33 and the sun gear 32 when the compressor/expander fluid machine 11 operates as an expander. As a result, it is possible to suppress a useless power consumption caused by driving the refrigerant pump 62 even when the Rankine cycle 61 is not operated. In addition, it is possible to provide a simple structure.

Fourth Embodiment

FIG. 13 is a skeleton diagram illustrating a fluid machine 1 according to a fourth embodiment, in which like reference numerals denote like elements as in FIG. 1 of the first embodiment. In the first to third embodiments, the planetary gear mechanism 31 is used to switch between the expander operation and the compressor operation. Meanwhile, according to the fourth embodiment, a transmission mechanism 121 is used instead of the planetary gear mechanism 31 in order to switch between the expander operation and the compressor operation.

As illustrated in FIG. 13, a transmission mechanism 121 includes a gear train of first, second, and third gears 123, 124, and 125 meshing with each other and a gear train of fourth and fifth gears 127 and 128 meshing with each other. Both the gear trains are arranged to face each other. The shafts of the second, third, and fifth gears 124, 125, and 128 are fixed to the housing 36. In this case, the first to third gears 123, 124, and 125 have the same number of teeth, and the fourth gear 127 has a larger number of teeth than that of the fifth gear 128.

The shaft of the first gear 123 and the shaft of the fourth gear 127 are positioned side by side and are connected to each other through the second clutch 42. In addition, the shaft of the third gear 125 and the shaft of the fifth gear 128 are positioned side by side and are connected to each other through first clutch 41.

When the scroll fluid machine 11 operates as an expander, the second clutch 42 is locked, and the first clutch 41 is released as illustrated in FIG. 14A. In this case, the rotation shaft 21 and the pulley 51 are connected in a direct linkage manner. That is, the pulley 51 is driven by kinetic power obtained by the scroll fluid machine 11 serving as an expander.

When the scroll fluid machine 11 operates as a compressor, the second clutch 42 is released, and the first clutch 41 is locked as illustrated in FIG. 14B. In this case, the rotation shaft 21 reversely rotates by the pulley 51. That is, by driving the scroll fluid machine 11 as a compressor using the engine power, it is possible to provide a refrigerant gas having a higher temperature and a higher pressure than those of the atmosphere by compressing the refrigerant gas. Since the rotational direction of the rotation shaft 21 is reverse to that of the pulley 51, and the fourth gear 127 has a larger number of teeth than that of the fifth gear 128, the rotation of the pulley 51 can be transmitted to the rotation shaft 21 in an accelerated manner. Therefore, it is possible to rotate the compressor (scroll fluid machine 11) in an accelerated manner.

The invention is not limited to those described above.

The application claims a priority of Japanese Patent Application No. 2012-090907 filed with the Japan Patent Office on Apr. 12, 2012, the entire content of which is incorporated herein by reference.

FLUID MACHINE AND RANKINE CYCLE

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CPC

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