JP2011025861A - Cooling device for power unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately control the amount of heat dissipation by a heat exchanger. <P>SOLUTION: A cooling device 50 for a power unit includes the heat exchanger 43 incorporating a power generation section for generating power into a power unit, and cooling water vapor and air from the power generation section; a cooling fan 44 for generating cooling wind supplied to the heat exchanger 43; and an exhaust duct 52 for guiding the cooling wind by connecting the heat exchanger 43 and the cooling fan 44. The exhaust duct 52 is composed of resin, and is attachedly supported by a metal support frame 46. The heat exchanger 43 and the cooling fan 44 are attached to an inlet opening 59 and an outlet opening 60 disposed on both sides of the exhaust duct 52, respectively, and are supported by a support frame 46 through the exhaust duct 52. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a power unit cooling apparatus, and more particularly, to a power unit cooling apparatus having a heat exchanger and a cooling fan in a power unit including a power generation unit.

  Most of the handle-type electric wheelchair vehicles currently sold are supplied with electric power for driving the electric motor from the battery, but in recent years, the fuel cell for supplying electric power generated by the fuel cell to the electric motor. On-board vehicles have been developed.

  The fuel cell generates electric power by an electrochemical reaction, and generates heat along with this reaction. Therefore, exhaust gas containing high-temperature water vapor is discharged from the fuel cell. On the other hand, in the direct methanol fuel cell system, methanol as a fuel is diluted and supplied to the fuel cell, and the water in the exhaust gas is used for this dilution.

  Therefore, a small electric motor having a direct methanol fuel cell system provided with a cooling device for flowing exhaust gas (air, water vapor, etc.) from the fuel cell into the heat exchanger and blowing cooling air from the cooling fan to the heat exchanger. A vehicle is disclosed in Patent Document 1. This cooling device condenses water vapor in the exhaust gas to produce water.

JP 2008-74201 A

  However, in the cooling device described in Patent Document 1, since the heat exchanger is directly attached to the metal support member fixed to the vehicle body frame, the heat of the heat exchanger is radiated through the support member. Or heat is absorbed into the heat exchanger. For this reason, the amount of heat released from the heat exchanger cannot be accurately controlled by the amount of cooling air generated by the operation of the cooling fan, so that dilution water is generated too much and overflows, or the generated water is insufficient and dilution of fuel becomes inappropriate. The fuel cell system may stop.

  In addition, the cooling air from the cooling fan may not be uniformly applied to the entire surface of the heat exchanger. In this case, the cooling efficiency of the heat exchanger will be reduced, and the cooling performance will not be increased unless the heat exchanger is enlarged. There is a risk that it cannot be secured.

  An object of the present invention is to provide a cooling device for a power unit capable of accurately controlling the amount of heat released by a heat exchanger, in consideration of the above-described circumstances.

  According to the present invention, a power generation unit that generates electric power is provided in an electric power unit, a heat exchanger that cools fluid from the power generation unit, a cooling fan that generates cooling air to the heat exchanger, and the heat exchanger And a duct for connecting the cooling fan to guide the cooling air, and the duct is made of resin and supported by being attached to a metal support frame, The heat exchanger and the cooling fan are attached to openings provided on both sides of the duct, and are supported by the support frame body through the duct.

  According to the present invention, the heat exchanger does not contact the metal support frame having a high thermal conductivity, but contacts the resin duct having a low thermal conductivity, and the support frame is interposed through the duct. Supported by the body. For this reason, since the heat exchanger is thermally insulated from the support frame, the amount of heat released by the heat exchanger can be accurately controlled by the amount of cooling air generated by the operation of the cooling fan.

1 is an overall side view showing an electric vehicle equipped with a fuel cell to which an embodiment of a cooling device for an electric power unit according to the present invention is applied. The perspective view which shows the electric power unit in the power chamber inside the vehicle body cover of FIG. The perspective view which expands and shows a part (cooling device) in the electric power unit of FIG. The front view which shows the cooling device of FIG. The top view which shows the cooling device of FIG. FIG. 4 is a horizontal sectional view showing the cooling device of FIG. 3. The block diagram which shows the system configuration | structure of a fuel cell system.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 is an overall side view showing an electric vehicle equipped with a fuel cell to which an embodiment of a cooling device for an electric power unit according to the present invention is applied.

  A handle type electric wheelchair vehicle 10 as an electric vehicle equipped with a fuel cell shown in FIG. 1 is provided with a pair of left and right front wheels 11 at the front end of the vehicle and a pair of left and right rear wheels 12 at the rear end of the vehicle. A low floor footrest floor 13 as a footrest portion for the driver is installed in the section, and a driving seat 14 is installed at the rear of the vehicle. Electricity is supplied to the space covered by the vehicle body cover 15 below the driving seat 14. A power chamber 17 accommodating the unit 16 (FIG. 2) is provided and configured.

  The footrest floor 13 shown in FIG. 1 is formed in a flat shape so that a single driver sitting on the driving seat 14 can place his / her feet together. The driving seat 14 is configured as a chair with a backrest.

  As shown in FIG. 2, the power unit 16 is configured in a hybrid type having a fuel cell system 18 and a secondary battery 19. The electric power unit 16 supplies electric power (electric energy) generated in the fuel cell system 18 and electric power from the secondary battery 19 storing the electric power to a drive unit 20 (FIG. 1) equipped with an electric motor. Then, the rear wheel 12 is driven.

  The vehicle body frame 21 of the handle type electric wheelchair vehicle 10 described above is a platform-type vehicle body frame, and includes a main frame 22 arranged in a pair of left and right in the vehicle width direction, and a plurality of beam members 23 installed between the main frames 22. (FIG. 2). Further, a floor member 24 for the footrest floor 13 is installed between the pair of main frames 22 on the center front side of the main frame 22. Further, a seat pipe 25 formed in a curved shape is straddled at the rear portion of the main frame 22, and a seat post 26 that supports the operation seat 14 is attached to the center top portion of the seat pipe 25.

  As shown in FIG. 1, the front wheel 11 is pivotally supported at the front end portion of the vehicle body frame 21 thus configured by a steering mechanism including a front wheel suspension device (not shown) and a steering post 27 so as to be steerable to the left and right. . The steering post 27 extends upward in a leg shield 28 that covers the driver's feet, and a steering handle 29 is integrally provided at the upper end thereof. The front wheel 11 is steered left and right by a steering handle 29 via a steering post 27.

  A front end portion of the drive unit 20 is pivotally attached to a pivot bracket 30 provided at the rear end portion of the vehicle body frame 21 so as to be swingable in the vertical direction. The drive unit 20 is seated on the seat of the vehicle body frame 21 by a cushion unit 31. The pipe 25 is elastically supported. The drive unit 20 includes an electric motor and a gear case (both not shown).

  The power unit 16 (FIG. 2) of the power chamber 17 disposed below the operation seat 14 has a fuel cell system 18, which is a direct methanol fuel cell system. In the direct methanol fuel cell system, methanol is used as a fuel and is directly input to the negative electrode of a fuel cell (direct methanol fuel cell) as a power generation unit to generate electric energy.

  This direct methanol fuel cell system will be described with reference to FIG. By supplying fuel to the negative electrode of the cell stack 32 as a fuel cell and supplying air (oxygen) to the positive electrode, an electrochemical reaction occurs in the cell stack 32 to generate electric power, and carbon dioxide is applied to the negative electrode. Water is generated at the positive electrode.

  As for the fuel system, the fuel (for example, 54% methanol aqueous solution) stored in the fuel tank 33 is supplied to the circulation tank 35 by the fuel pump 34, and the optimum concentration (for example, 3% methanol aqueous solution) is obtained by water in the circulation tank 35. Diluted to The diluted fuel is sent to the negative electrode of the cell stack 32 by the circulation pump 37 after impurities are removed by a fuel filter (not shown).

  Since the output characteristics of the cell stack 32 are greatly influenced by the fuel concentration, the fuel concentration (methanol aqueous solution concentration) in the circulation tank 35 is monitored, and the driving of the water pump 38 and the fuel pump 34 is controlled based on this concentration information. Water is supplied from the water tank 39 and fuel is supplied from the fuel tank 33 into the circulation tank 35, and the fuel concentration in the circulation tank 35 is adjusted to an optimum concentration.

  Further, unreacted fuel discharged from the negative electrode outlet of the cell stack 32 and carbon dioxide generated by the electrochemical reaction are led to the circulation tank 35 through the metal ion adsorption filter 40, and the unreacted fuel is reused as fuel. Then, the carbon dioxide is introduced into the water tank 39. The metal ion adsorption filter 40 adsorbs and removes metal ions in the unreacted fuel (aqueous methanol solution), thereby preventing the power generation efficiency of the cell stack 32 from being lowered.

  Regarding the air system, impurities in the air are removed by the air filter 41, and air (oxygen) is pumped to the positive electrode of the cell stack 32 by the compressor 42. From the positive electrode outlet of the cell stack 32, unreacted air and water generated by the electrochemical reaction are discharged.

  Here, since the optimum operating temperature of the cell stack 32 is relatively high, such as about 70 ° C. to 80 ° C., most of the generated water is in the state of water vapor. In order to dilute the fuel (methanol) in the circulation tank 35, it is necessary to make the produced water into a water state and store it in the water tank 39. Therefore, unreacted air and water vapor at the positive electrode outlet of the cell stack 32 are introduced into the heat exchanger 43, and the cooling air is guided to the heat exchanger 43 by the operation of the cooling fan 44. Cooling and coagulating water vapor increase the recovery rate of product water. This recovered product water is used for diluting the fuel as described above.

  Unreacted air and water vapor cooled by the heat exchanger 43 and carbon dioxide discharged to the water tank 39 are mixed in the water tank 39, and harmful components are removed by the exhaust filter 45, and then discharged to the atmosphere. The

  The layout of the components of the power unit 16 including the fuel cell system 18 configured as described above will be described below.

  As shown in FIGS. 1 and 2, in the power unit 16, the fuel cell system 18 described above is disposed in the power chamber 17 on the front side in the vehicle traveling direction with the seat pipe 25 as a boundary, and the secondary battery 19 on the rear side. A data logger 47 and a fuel cell system controller 48 for controlling the fuel cell system 18 are arranged. The data logger 47 stores data relating to the state of the fuel cell system 18 during vehicle operation.

  In the fuel cell system 18, a cell stack 32, a circulation tank 35, a metal ion adsorption filter 40, a water tank 39 (not shown in FIG. 2) and the like are disposed at the lower front side of the power chamber 17. Further, in the fuel cell system 18, an air filter 41, a compressor 42, an exhaust filter 45, a circulation pump 37, a water pump 38, and a cooling device 50 (that is, a heat exchanger 43, a cooling fan 44, an intake port) are disposed on the upper front side of the power chamber 17. A duct 51, a discharge duct 52 (both will be described later) and the like are arranged. Devices such as the compressor 42, the exhaust filter 45, and the cooling device 50 disposed on the upper front side of the power chamber 17 are supported on the vehicle body frame 21 by a support frame body 46 attached to the vehicle body frame 21.

  On the other hand, as shown in FIG. 1, the fuel tank 33 is disposed in a space in front of the steering post 27 in the leg shield 28 and is configured in a plate shape having a small size in the vehicle front-rear direction and a large size in the vehicle vertical and horizontal directions. Has been. Reference numeral 49 denotes a fuel supply port to the fuel tank 33.

  As described above, the cooling device 50 cools the air and water vapor discharged from the positive electrode of the cell stack 32 (FIG. 7), condenses the water vapor, and recovers it as water, as shown in FIGS. Thus, the heat exchanger 43, the cooling fan 44, the suction duct 51, and the discharge duct 52 are configured. Here, as shown in FIG. 1, the vehicle body cover 15 has a cooling air intake 55 on the front wall 53 on the side of the footrest floor 13 for the driver, and a cooling air discharge port 56 on the side wall 54 in the vehicle width direction. Each is formed.

  The heat exchanger 43 shown in FIG. 3 to FIG. 5 has cooling air generated by the operation of the cooling fan 44 (arrows in FIG. 3, FIG. 5, and FIG. 6) while the steam and air discharged from the cell stack 32 flow inside. A) is used for cooling. The cooling fan 44 generates the cooling air.

  The suction duct 51 is made of a synthetic resin and has a box shape. A suction opening 57 is formed on the front side of the vehicle, and an outflow opening 58 is formed on one side in the vehicle width direction. The suction opening 57 is disposed opposite to the cooling wind intake 55 of the vehicle body cover 15 and the outflow opening 58 is opposed to the heat exchanger 43. Therefore, by the operation of the cooling fan 44, the outside air is taken in as cooling air from the cooling air intake 55 of the vehicle body cover 15, and travels through the suction duct 51 from the suction opening 57 to the outflow opening 58 as shown in FIG. Flowing in a direction perpendicular to the

  As shown in FIGS. 3 to 5, the discharge duct 52 is made of a synthetic resin and formed in a box shape, and an inflow opening 59 as a first opening is formed on one side in the vehicle width direction, and on the other side. A discharge opening 60 is formed as a second opening. A connecting portion 61 is provided on the bottom surface side of the discharge duct 52, and the connecting portion 61 is attached to the support frame body 46 made of metal using a bolt or the like, so that the discharge duct 52 is fixed to the support frame body 46. To be supported. The heat exchanger 43 is attached to the inflow opening 59 of the discharge duct 52, and the cooling fan 44 is fixed to the discharge opening 60 by bolts or the like. Accordingly, the heat exchanger 43 and the cooling fan 44 are supported by the metal support frame 46 via the synthetic resin discharge duct 52.

  In this attached state, the discharge duct 52 connects the heat exchanger 43 and the cooling fan 44, and the cooling fan 44 is disposed corresponding to the cooling air discharge port 56 (FIG. 1) of the vehicle body cover 15. Therefore, the cooling air that has flowed from the suction duct 51 into the heat exchanger 43 and increased in temperature by heat exchange by the operation of the cooling air 44 is guided from the heat exchanger 43 to the discharge duct 52 and flows toward the cooling fan 44. The air is discharged from the cooling air outlet 56 of the vehicle body cover 15 to the side of the vehicle.

  The inflow opening 59 of the discharge duct 52 is formed in a rectangular shape corresponding to the side shape of the heat exchanger 43. Further, the discharge opening 60 of the discharge duct 52 is formed in a square shape or a circular shape corresponding to the side shape of the cooling fan 44. Therefore, the inflow opening 59 is configured to have a larger opening area than the discharge opening 60. Further, as shown in FIG. 6, a plurality of partition plates 62 </ b> A, 62 </ b> B, 62 </ b> C extending from the inflow opening 59 toward the discharge opening 60 are provided inside the discharge duct 52. All the 60 regions are arranged at a predetermined interval (for example, substantially equal intervals). These partition plates 62 </ b> A, 62 </ b> B, 62 </ b> C are erected so as to extend along the vertical direction of the discharge duct 52.

  By these partition plates 62A, 62B, and 62C and the side wall of the discharge duct 52, the space in the discharge duct 52 is divided into a plurality of flow paths 63A, 63B, 63C, and 63D from the heat exchanger 43 to the cooling fan 44. The The flow path cross-sectional areas of these flow paths 63A to 63D are formed substantially the same, for example. As described above, a plurality of partition plates 62A, 62B, and 62C are provided in the discharge duct 52, and the flow paths 63A, 63B, 63C, and 63D are formed in the discharge duct 52, whereby each of the flow paths 63A to 63D. The flow of the cooling air flowing through is rectified. At the same time, in the heat exchanger 43, from the portion A2 (FIG. 5) that has been removed without facing the cooling fan 44, these portions A1 and A2 are moved in the same manner as the portion A1 (FIG. 5) facing the cooling fan 44. The flowing cooling air is guided and sucked in the same manner by the cooling fan 44.

  With the configuration as described above, according to the present embodiment, the following effects (1) to (4) are achieved.

  (1) A synthetic resin exhaust duct 52 is attached to and supported by a metal support frame 46, and a heat exchanger 43 and a seven cooling fan 44 are attached to the exhaust duct 52. It is supported by the support frame 46. In this way, the heat exchanger 43 does not contact the metal support frame 46 having a high thermal conductivity, but contacts the resin discharge duct 52 having a low thermal conductivity. And supported by the support frame 46. For this reason, since the heat exchanger 43 is thermally insulated from the support frame 46, the heat radiation amount by the heat exchanger 43 can be accurately controlled only by the cooling air amount by the operation of the cooling fan 44. Accordingly, in the direct methanol fuel cell system 18, the amount of product water condensed in the heat exchanger 43 and used for diluting the fuel (methanol) can be accurately controlled. Stopping of the fuel cell system 18 and overflow from the water tank 39 due to excess can be prevented.

  (2) In the discharge duct 52, a plurality of partition plates 62A, 62B, and 62C extending from the inflow opening 59 on the heat exchanger 43 side toward the discharge opening 60 on the cooling fan 44 side are provided with the inflow opening 59. The flow paths 63A, 63B, 63C, and 63D are formed in the discharge duct 52 at predetermined intervals in the entire areas of the discharge openings 60. For this reason, the cooling air that has flowed through the heat exchanger 43 by the operation of the cooling fan 44 is similarly sucked into the cooling fan 44 through the flow paths 63A to 63D. As a result, since the cooling air can be uniformly supplied to the entire heat exchanger 43 having a rectangular flow passage cross-sectional area, the cooling efficiency of the heat exchanger 43 is improved and the heat exchanger 43 is downsized. it can.

  (3) Partition plates 62 </ b> A, 62 </ b> B, 62 </ b> C formed in the discharge duct 52 are provided extending in the vertical direction of the discharge duct 52. Therefore, since these partition plates 62A to 62C serve as reinforcing members, the rigidity of the discharge duct 52 can be increased, and the durability of the discharge duct 52 can be improved.

  (4) The vehicle body cover 15 has a cooling air intake 55 on the front wall 53 on the side of the footrest floor 13 and a cooling air discharge port 56 on the side wall 54. The rising cooling air is discharged to the side of the vehicle through the cooling air discharge port 56. Therefore, since the cooling air whose temperature has risen does not directly hit the driver, the driver does not feel uncomfortable. Further, since the cooling fan 44 is disposed on the side of the vehicle corresponding to the cooling air discharge port 56 of the vehicle body cover 15, it is possible to prevent the noise of the cooling fan 44 from being directly transmitted to the driver.

  As mentioned above, although this invention was demonstrated based on the said embodiment, this invention is not limited to this.

  For example, although the case where the fuel cell system 18 is a direct methanol fuel cell system has been described in the present embodiment, the present invention may be applied to other fuel cell systems, for example, a methanol reforming fuel cell system. Further, in the present embodiment, the case where the vehicle is the handle type electric wheelchair vehicle 10 has been described, but the present invention may be applied to other fuel cell mounted electric vehicles.

10 Handle-type electric wheelchair vehicle (electric vehicle equipped with fuel cell)
13 Foot rest floor (foot rest)
14 Driving seat 15 Car body cover 16 Electric power unit 18 Fuel cell system 32 Cell stack (power generation unit)
43 Heat exchanger 44 Cooling fan 50 Cooling device 52 Exhaust duct 53 Front wall 54 Side wall 55 Cooling air inlet 56 Cooling air outlet 59 Inlet opening 60 Outlet opening 61 Coupling parts 62A, 62B, 62C Partition plate

Claims (6)

A power generation unit that generates power is provided in the power unit,
A heat exchanger that cools the fluid from the power generation unit, a cooling fan that generates cooling air to the heat exchanger, and a duct that guides the cooling air by connecting the heat exchanger and the cooling fan. In the cooling device of the power unit having
The duct is made of resin and supported by being attached to a metal support frame,
The electric power unit cooling apparatus, wherein the heat exchanger and the cooling fan are attached to openings provided on both sides of the duct and are supported by the support frame through the duct. The duct has a first opening on the heat exchanger side having a larger area than the second opening on the cooling fan side, and extends from the first opening to the second opening in the duct. 2. The power unit cooling device according to claim 1, wherein a plurality of partition plates are arranged at predetermined intervals in each of the first opening and the second opening. The cooling device for a power unit according to claim 2, wherein the partition plate is provided so as to extend in a vertical direction of the duct. The electric power unit is housed in a space surrounded by a vehicle body cover below a driving seat on which a single driver is seated, and is mounted on an electric vehicle capable of traveling with electric power generated by the power generation unit. The cooling device for a power unit according to claim 1. 5. The power unit cooling apparatus according to claim 4, wherein the power generation unit is a direct methanol fuel cell. 5. The electric power according to claim 4, wherein the vehicle body cover is formed with a cooling air inlet on a front wall on a driver's footrest side and a cooling air outlet on a side wall in a vehicle width direction. Unit cooling device.

Images