Patent Grant
7544047
The present invention relates to a compressor which compresses gas supplied, for example, to a fuel cell.
Japanese Unexamined Patent Publication No. 2002-295386 discloses a compressor having a gas cooler in which discharge gas discharged from compression chambers is cooled in order to protect piping provided downstream of the compressor against heat (See pages 3 to 5 and FIG. 1 of the reference). The compressor of the above reference is a scroll type compressor which is provided with a back cooling chamber at the back of a fixed scroll member of the compressor. The gas cooler in which the discharge gas flows is disposed so as to adjoin the back cooling chamber. The gas cooler is constructed specifically such that both of gas in the compression chambers and the discharge gas in the gas cooler are cooled by cooling water that serves as cooling medium which flows in the back cooling chamber.
In the above reference, however, since the cooling water in the back cooling chamber is heated by heat of the discharge gas, the gas in the compression chambers tends to be hard to be cooled, so that there has been a fear that the efficiency of cooling the discharge gas is reduced. In addition, there has been another fear that the gas in the compression chambers is not cooled sufficiently by the cooling water in the back cooling chamber, but on the contrary it is heated by the cooling water in the back cooling chamber when temperature of the cooling water in the back cooling chamber becomes higher than that of the gas in the compression chambers by the heat of the discharge gas. The contact area (or heat radiation area) over which the back cooling chamber and the gas cooler are placed in contact with each other through a partition wall tends to be increased with the need to cool the discharge gas in the gas cooler. As the contact area is increased, however, the cooling water in the back cooling chamber tends to be heated by the heat of the discharge gas.
The present invention is directed to a compressor which improves discharge gas cooling efficiency while restraining a decrease in the efficiency of cooling the gas in a compression chamber.
The present invention has the following features. A compressor, which is cooled by cooling medium, includes a compression chamber, a first cooling chamber and a second cooling chamber. In the compression chamber, gas is compressed and then discharged therefrom. The first cooling chamber, in which the cooling medium flows, is provided so as to adjoin the compression chamber for cooling the gas in the compression chamber. The second cooling chamber adjoins the first cooling chamber. The second cooling chamber has a gas passage in which the discharged gas flows and a medium passage in which the cooling medium flows. The medium passage is arranged so as to restrain transmission of heat of the discharged gas in the gas passage to the cooling medium in the first cooling chamber.
Other aspects and advantages of the invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.
The features of the present invention that are believed to be novel are set forth with particularity in the appended claims. The invention, together with objects and advantages thereof, may best be understood by reference to the following description of the presently preferred embodiments together with the accompanying drawings in which:
A first preferred embodiment will be now described with reference to
Referring to
The compressor speed is so controlled that the compressor increases the amount of air which is supplied to the fuel cell FC for a given length of time with an increasing of running speed of the electric vehicle while it decreases the amount of air with a decrease of the running speed of the electric vehicle. Further, even in a state when the electric vehicle is at a stop for a red traffic signal, the compressor continues to be driven at a relatively low speed in order to operate other electrical equipment such as an electric type refrigerant compressor for an air conditioning apparatus. In
Now, the structure of the compressor will be described. Still referring to
In the second housing unit 12, an electric motor M is provided which includes a rotor 16 fixedly mounted on the rotary shaft 13 for rotation therewith and a stator 17 fixed on the inner peripheral surface of the second housing unit 12 so as to surround the rotor 16.
The first housing unit 11 includes a fixed scroll member 20, a front housing member 21 and a rear housing member 22. The front end of the fixed scroll member 20 is fixedly joined to the rear end of the front housing member 21. The rear end of the fixed scroll member 20 is fixedly joined to the front end of the rear housing member 22. The fixed scroll member 20 has a fixed base plate 20a and a fixed spiral wall 20b that extends from the rear surface of the fixed base plate 20a.
A main crankshaft 23 extends frontward from the front end of the rotary shaft 13 and is offset from the axis L of the rotary shaft 13 by a predetermined distance of eccentricity. A movable scroll member 24 is rotatably supported by the main crankshaft 23 through a bearing 25 so as to face the fixed scroll member 20.
The movable scroll member 24 includes a movable base plate 24a that is substantially disc-shaped and a movable spiral wall 24b that extends from the front surface of the movable base plate 24b. The fixed and movable scroll members 20 and 24 are arranged so as to engage with each other. The distal end surfaces of the fixed and movable spiral walls 20b and 24b are in contact with the facing movable and fixed base plates 24a and 20a, respectively. The fixed spiral wall 20b overlaps the movable spiral wall 24b to contact each other at a plurality of points. Therefore, the fixed base plate 20a and the fixed spiral wall 20b of the fixed scroll member 20 as well as the movable base plate 24a and the movable spiral wall 24b of the movable scroll member 24 define a plurality of compression chambers 26 that serves as enclosed space.
A cylinder 24c protrudes axially from the intermediate portion of the movable base plate 24a toward the front and rear sides of the compressor so as to receive therein the main crankshaft 23. The cylinder 24c is closed at its front end by a bottom wall and open at its rear end. Thus, the main crankshaft 23 protrudes in the cylinder 24c from the movable base plate 24a toward the fixed base plate 20a. Consequently, the compressor is shortened along the axis L of the rotary shaft 13 by a length of the main crankshaft 23 that protrudes from the movable base plate 24a toward the fixed base plate 20a.
A discharge port 20c is formed in the scroll member 20 substantially at the center of the fixed base plate 20a. An outlet 21a is formed substantially at the center of the front housing member 21 on the front side of the fixed scroll member 20. The fixed scroll member 20 and the movable scroll member 24 define a central chamber 27 substantially at a central part of the scroll of the fixed spiral wall 20b on the rear side of the fixed scroll member 20. The discharge port 20c interconnects the outlet 21a with the central chamber 27. An air filter 28 is arranged in the discharge port 20c.
Three bosses 24d are formed on the movable base plate 24a of the movable scroll member 24, extending from the back of the movable base plate 24a or from the rear surface thereof (only one boss 24d is shown in
Now, a channel of cooling water that serves as a cooling medium in the electric vehicle and a channel of gas discharged from the compression chamber 26 will be described.
The electric vehicle is provided with a circulation channel 36 of the cooling water for cooling the fuel cell FC. The circulation channel 36 includes a radiator 37 and a water pump 38. The radiator 37 serves as a heat exchanger. The cooling water whose temperature has been increased by cooling the fuel cell FC is cooled down by the radiator 37 and then fed by the water pump 38 to cool the fuel cell FC. Thus, the cooling water recirculates in the channel for cooling the fuel cell FC.
The electric motor M is covered by a water jacket 39 that serves as a motor cooling member. A part of the cooling water in the circulation channel 36 is supplied into the water jacket 39 through a passage 40 which is diverged from the circulation channel 36 between the water pump 38 and the fuel cell FC. Thus, the electric motor M is cooled.
In the fixed scroll member 20, the front surface of the fixed base plate 20a, or the back of the fixed base plate 20a with respect to the compression chambers 26, is formed with recesses. The recessed portions of the front surface of the fixed base plate 20a are covered with the front housing member 21 thereby to define a back cooling chamber 41 for cooling the compression chambers 26. The cooling water which has passed through the water jacket 39 flows into this back cooling chamber 41 through a passage 42.
The back cooling chamber 41 is arranged to adjoin the compression chambers 26, so that heat exchange is performed between the cooling water in the back cooling chamber 41 and the air in the compression chambers 26, with the result that the air in the compression chambers 26 is cooled and, therefore, temperature rise of the air in the compression chambers 26 is regulated.
An inlet 41a of the back cooling chamber 41 is formed on the upper side and an outlet 41b of the back cooling chamber 41 is formed on the lower side of the cooling chamber 41, respectively, as seen in
As shown in
A case 52 of the inter-cooler 51 has a shape of box and is opened at one end. The opening of the case 52 is covered by the front housing member 21 thereby to define an internal space of the case 52 that serves as a discharge-gas cooling chamber 52a.
A gas passage 53 and a medium passage 54 are formed in the internal space of the case 52. The gas, or air in the present preferred embodiment, discharged from the compression chambers 26 flows into the gas passage 53. The cooling medium, or cooling water in the present preferred embodiment, flows into the medium passage 54. A plurality of branched tubes 54a extends vertically in the case 52. As shown in
As shown in
An inlet 54b of the medium passage 54 is formed at the bottom of the inter-cooler 51 and connected to the outlet 41b of the back cooling chamber 41 by an inflow passage 56. An outlet 54c of the medium passage 54 is formed at the top of the inter-cooler 51 and connected to the radiator 37 by an outflow passage 57 and a passage 58.
The gas passage 53 is formed such that the gas or air flows around a wall 59, which is formed extending perpendicularly to the plane of
As shown in
Now, the function of the aforementioned compressor will be described.
As the rotary shaft 13 is rotated by the electric motor M, the movable scroll member 24 orbits around the axis L of the rotary shaft 13 by the main crankshaft 23. At the same time, the self-rotation preventing mechanism 34 prevents the movable scroll member 24 from self-rotating while it allows the movable scroll member 24 to orbit around the axis L of the rotary shaft 13. As the compression chambers 26 are moved inwardly from the outer periphery of the fixed and movable spiral walls 20b and 24b by the orbital movement of the movable scroll member 24, the compression chambers 26 reduce in volume.
In the compressor, the air which is supplied to the compressor is introduced from the outer peripheral side of the fixed and movable spiral walls 20b and 24b into the compression chambers 26. Subsequently, the air is compressed by the aforementioned movement of the compression chambers 26. The compressed air is discharged from the compression chambers 26, which have then approached the center of the fixed base plate 20a, through the central chamber 27, the discharge port 20c and the outlet 21a. The air discharged from the compression chambers 26 through the outlet 21a then flows from the inlet 53a into the gas passage 53 of the inter-cooler 51. In the gas passage 53, the air flows as shown by outlined arrows in
On the other hand, the cooling water cooled by the radiator 37, pressurized by the water pump 38 and flown to the passage 40 is supplied to the water jacket 39, thereby to cool the electric motor M. The cooling water, which has passed through the water jacket 39, then flows into the back cooling chamber 41 through the passage 42. In the back cooling chamber 41, the cooling water flows as shown by arrows in
The cooling water which has passed through the back cooling chamber 41 and out from the outlet 41b flows into the medium passage 54 through the inflow passage 56 and the inlet 54b as shown by arrows in
The cooling water in the tubes 54a which adjoins the front housing member 21 absorbs heat of the discharge air in the gas passage 53. Thus, transmission of heat of the discharge air in the gas passage 53 to the back cooling chamber 41 is reduced. The discharge air in the gas passage 53 is cooled to such a temperature at which the rubber hose 60 can perform its function properly without deteriorating its quality.
Flows of the cooling water which has passed through the medium passage 54 join together at the top of the inter-cooler 51 and returned to the radiator 37 through the inflow passage 57 and the outflow passage 58 to be cooled. The cooling water which has been cooled by the radiator 37 is fed again to the fuel cell FC by the water pump 38 for cooling the fuel cell FC. The cooling water, which has been cooled by the radiator 37, is fed also to the water jacket 39, by the water pump 38.
The present preferred embodiment achieves the following advantageous effects.
A second preferred embodiment of the present invention will be now described with reference to
The inlet 54a of the medium passage 54 is connected to the water jacket 39 through a passage 62 which is branched off from the passage 42 which connects the water jacket 39 to the back cooling chamber 41. Therefore, the cooling water which has flowed through the water jacket 39 is divided into two flows, one flowing into the back cooling chamber 41 and the other into the inter-cooler 51. In
In the second preferred embodiment, the above-described effects (2) through (7) of the first preferred embodiment are substantially obtained. In addition, the following effect (8) is also obtainable.
In the present embodiment, the following alternative embodiments are also practiced.
In the above-described embodiments, the tubes 54a, which adjoin the front housing member 21, are arranged separately. The gas passage 53 and the back cooling chamber 41 are arranged so as not to partially adjoin each other. In alternative embodiments to the embodiments, the tube 54a is arranged in such a manner that the gas passage 53 and the back cooling chamber 41 do not adjoin each other. As shown in
In the above-described embodiments, at least one tube 54a is disposed so as to adjoin the front housing member 21. However, the arrangement of the tube 54a is not limited to such arrangement, but the tube 54a is disposed in such a manner that the transmission of heat of the discharge air to the cooling water in the back cooling chamber 41 by the cooling water in the tube 54 is reduced. In alternative embodiments to the embodiments, therefore, at least one tube 54a is spaced from the front housing member 21 by a predetermined distance, as shown in
In the above-described embodiments, each tube 54a is shaped flat in cross-section. The shape of the tube 54a is not limited to flatness. In alternative embodiments to the embodiments, each tube 54a is cylindrical in cross-section, as shown in
In the above-described embodiments, the inter-cooler 51 is constructed in such a manner that the cooling water flows inside the tubes 54a and that the discharge air flows outside the tubes 54a. In alternative embodiments to the embodiments, the discharge air may flow inside the tubes and the cooling water may flow outside tubes. In this case, with the tubes spaced from the front housing member 21 by a predetermined distance, as shown in
In the above-described embodiments, the electric motor M is cooled by the cooling water which flows in the water jacket 39. In alternative embodiments to the embodiments, the electric motor M may be made as air-cooled type so that the water jacket 39 is eliminated. In the alternative embodiment to the first preferred embodiment, the cooling water is fed from the water pump 38 to the back cooling chamber 41. In the alternative embodiment to the second preferred embodiment, the cooling water is fed from the water pump 38 to the back cooling chamber 41 and the inter-cooler 51 by two divided into flows.
In the above-described embodiments, the gas compressed by the compressor is air. It is noted, however, that gas is not limited to air, but, in alternative embodiments to the embodiments, the gas includes hydrogen that serves as a fuel for use in the fuel cell FC.
In the above-described embodiments, the cooling medium is water. The cooling medium is not limited to the water, but, in alternative embodiments to the embodiments, the cooling medium includes air.
In the above-described embodiments, the compressor is for use with the fuel cell in the electric vehicle. In alternative embodiments to the embodiments, the compressor is used with other fuel cells than that in the electric vehicle. In yet alternative embodiments to the embodiments, the compressor is not limited to be used with the fuel cell, but the compressor is a refrigerant compressor for use in a vehicle air conditioning apparatus.
In the above-described embodiments, the case 52 of the inter-cooler 51 is constructed in such a manner that its opening is covered by the front housing member 21 thereby to define therein the discharge-gas cooling chamber 52a. In alternative embodiments to the embodiments, the case 52 is provided with a cover which adjoins the front housing member 21 in such a manner that the case 52 itself defines therein the discharge-gas cooling chamber 52a. In this case, the tubes 54a, which adjoin the front housing member 21, adjoin the cover of the case 52.
In the above-described embodiments, the air filter 28 is arranged in the discharge port 20c. In alternative embodiments to the embodiments, the air filter 28 is arranged between the inter-cooler 51 and the fuel cell FC.
In the above-described embodiments, the power for driving the compressor thereby to compress the gas in the compression chambers 26 is supplied by the electric motor M provided in the compressor. In alternative embodiments to the embodiments, the power or running torque for driving the vehicle wheels is transmitted to the rotary shaft 13 through a belt.
The above-described embodiments are applied to a scroll type compressor. In alternative embodiments to the embodiments, however, the scroll type compressor is substituted by a compressor of other type such as a swash plate type piston compressor or a vane type compressor.
Therefore, the present examples and embodiments are to be considered as illustrative and not restrictive and the invention is not to be limited to the details given herein but may be modified within the scope of the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2003-097045 | Mar 2003 | JP | national |
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| Number | Date | Country | |
|---|---|---|---|
| 20040191100 A1 | Sep 2004 | US |
