Cooling structure for vehicle power generation units

Abstract

To improve the cooling performance of a power generation unit for vehicles in a compact layout.SOLUTION: A cooling structure for a power generation unit for vehicles comprises a unit case 10 in which an engine 20 for power generation, etc., is accommodated and which is removably mounted on a vehicle. A first electric fan 31 including a rotation axis 31a is provided in the unit case 10, and the rotation axis 31a and a crank part 23 are disposed to be overlapped in a view in a direction orthogonal to a length direction of the crank part 23. In the unit case 10, a first exhaust port is provided at a position where a distance between the first exhaust port and the first electric fan 31 is maximum inside of the unit case 10 and a wind conducting path, in which air is circulated, is provided between the first electric fan 31 and the first exhaust port.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a cooling structure for a vehicle power generation unit.

Background Art

[0002] For example, as disclosed in Patent Document 1, a small power generation unit capable of generating power by driving a power generation engine is known. In the box-shaped unit case of the power generation unit, electrical equipment such as a generator, a power generation engine, a fuel tank, an inverter, and a cooling device are housed.

[0003] On the other hand, an electric vehicle having a battery for driving an electric motor is known in which a vehicle equipped with the above-described small power generation unit is mounted. The vehicle mounts the power generation unit and can extend the cruising range by supplying power to the battery or the electric motor. Such a power generation unit is removably mounted, for example, in a space provided at the lower part in the rear of the vehicle.

[0004] By configuring the power generation unit to be removable from the vehicle body in this way, the maintainability is improved, and further, it is possible to use the power generation unit alone at a location away from the vehicle. However, since such a power generation unit has a limited installation space, it is required to be configured more compactly and to have a predetermined cooling performance.

[0005] For example, the engine generator disclosed in Patent Document 1 attempts to improve the cooling efficiency by providing two systems of air guiding paths through which cooling air flows.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

[0007] In the structure of the example above, two airflow paths are secured by providing an airflow path within the engine generator housing that is configured to match the structure of the power generation engine and generator. As a result, the housing in the example above has a hollow section between the outer and inner walls, which increases the volume of the housing. As mentioned above, in order to mount a small power generation unit on a vehicle, a compact structure is required. Therefore, in a housing with a cooling structure like the example above, there was room for improvement in making the power generation unit more compact.

[0008] The present invention was made to solve the above problems, and its objective is to provide a cooling structure for a vehicle power generation unit that can improve the cooling performance of the power generation unit while maintaining a compact configuration. [Means for solving the problem]

[0009] To achieve the above objective, the cooling structure for a vehicle power generation unit according to the present invention comprises a power generation engine having a crank section, a generator connected to the power generation engine, and a unit case housing the power generation engine and the generator, which is detachably attached to a vehicle. In the cooling structure for the vehicle power generation unit, the unit case is provided with a first electric fan having a rotating shaft, the rotating shaft and the crank section are arranged to overlap when viewed from a direction perpendicular to the longitudinal direction of the crank section, the unit case is provided with a first exhaust port, the first exhaust port is provided at a position within the unit case where the distance from the first electric fan is maximum, and an air guide path is provided between the first electric fan and the first exhaust port through which air flows. [Effects of the Invention]

[0010] According to the present invention, it is possible to improve the cooling performance of the power generation unit while making the power generation unit compact. [Brief explanation of the drawing]

[0011] [Figure 1] This is a perspective view of the vehicle power generation unit according to the present invention, as seen from the front. [Figure 2] Figure 1 is a perspective view of the power generation unit as seen from the rear. [Figure 3] Figure 1 is a top view of the power generation unit. [Figure 4] Figure 1 is a bottom view of the power generation unit. [Figure 5] This is a schematic plan view showing the power generation unit with its outer cover and other components removed. [Figure 6] Figure 5 is a schematic plan view showing the positions of the power generation unit's mounts, etc. [Figure 7] Figure 5 is a plan view of the first electric fan at the center of its rotation axis. [Figure 8] This is a longitudinal cross-sectional view taken along arrow AA in Figure 7. [Figure 9] This is a longitudinal cross-sectional view taken along the arrow BB in Figure 7. [Figure 10] This is a longitudinal cross-sectional view taken along the CC arrow in Figure 8. [Modes for carrying out the invention]

[0012] Hereinafter, an embodiment of the cooling structure of the vehicle power generation unit 1 according to the present invention will be described with reference to the drawings (Figures 1 to 10). In the figures, the direction of arrow Fr indicates the front in the vehicle's longitudinal direction (unit's longitudinal direction). In the description of the embodiment, "front (front end) and rear (rear end)" correspond to the front and rear in the vehicle's longitudinal direction (unit's longitudinal direction). Also, arrows R and L indicate the right and left sides when an occupant looks forward to the front of the vehicle (when looking forward in the unit's longitudinal direction). Also, arrow D indicates the top of the vehicle.

[0013] The power generation unit 1 for a vehicle according to the present embodiment is detachably attached, for example, under the floor such as a luggage space provided at the rear of the vehicle. Although the description by illustration is omitted, the power generation unit 1 is fixed to the rear of the vehicle in a state of being inserted into the vehicle through an opening provided at the rear of the vehicle. In this case, the power generation unit 1 is arranged, for example, between the left and right rear wheels in the vehicle width direction and is attached to a highly rigid rear side member and rear cross member that constitute the vehicle body skeleton.

[0014] As shown in FIGS. 5 and 7, the power generation unit 1 of the present embodiment includes a power generation engine 20, a generator 30, a plurality of electrical components such as an inverter 35, a first electric fan 31, a second electric fan 32, a fan cowl 40, a fuel tank 24, and a muffler 25. These are housed inside a substantially rectangular parallelepiped unit case 10 shown in FIGS. 1 to 4. Hereinafter, each member and device will be described.

[0015] First, the configuration of the unit case 10 will be described. The power generation unit 1 including the unit case 10 is substantially rectangular parallelepiped as a whole. That is, the unit case 10 constituting the exterior of the power generation unit 1 is substantially rectangular parallelepiped as a whole as shown in FIGS. 1 to 4. Note that a part of the exterior of the power generation unit 1 includes a part of the outer wall of the fuel tank 24 and a part of the outer wall of the muffler 25. These will be described later.

[0016] In the following description, the longitudinal direction of the power generation unit 1 corresponds to the vehicle width direction and the left - right direction when attached to the vehicle body, and the short - hand direction of the power generation unit 1 corresponds to the vehicle front - rear direction. In the present embodiment, the front part and the rear part of the power generation unit 1 correspond to the front part and the rear part in the short - hand direction (unit front - rear direction) of the power generation unit 1, and the left - right direction (unit width direction) of the power generation unit 1 corresponds to the left and right when facing the front of the power generation unit 1.

[0017] On the outside of the unit case 10, a body mounting portion 14 for mounting to a vehicle and the like are provided. The power generation unit 1 is attached to the rear of the vehicle, for example, such that the longitudinal direction of the unit case 10 is along the vehicle width direction.

[0018] Also, as shown in FIGS. 1 to 4, the unit case 10 of the present embodiment has a tray 11 and an exterior cover 15. The tray 11 has a rectangular bottom portion 12 on which a power generation engine 20, a generator 30, and the like are installed, and side walls 13 that project upward from each end of the bottom portion 12 and extend along the ends.

[0019] As shown in FIGS. 1 and 2, the side walls 13 project upward from the left and right ends of the unit case 10 and extend along the unit front-rear direction. In this example, as shown in FIGS. 1 and 2, the side walls 13 are provided with a body mounting portion 14 for installing the power generation unit 1 to the vehicle body. The body mounting portion 14 may have, for example, rollers for traveling on rails provided on the vehicle body.

[0020] Also, as shown in FIG. 4, the bottom portion 12 of the tray 11 of the present embodiment has a first air outlet 12a, a second air outlet 12b, and a third air outlet 12c. The first air outlet 12a is disposed at the right corner portion at the rear of the bottom portion 12 of the tray 11. The first air outlet 12a has a substantially rectangular through-hole extending in the unit width direction, and the plurality of through-holes are arranged at intervals in the unit front-rear direction.

[0021] The second exhaust port 12b is located at the left corner of the front of the bottom 12. Similar to the first exhaust port 12a, the second exhaust port 12b has a substantially rectangular through-hole extending in the unit width direction, and the multiple through-holes are spaced apart from each other in the front-to-back direction of the unit. The third exhaust port 12c is located at the left corner of the rear of the bottom 12. Similar to the first and second exhaust ports 12a and 12b, the third exhaust port 12c has a substantially rectangular through-hole extending in the unit width direction, and the multiple through-holes are spaced apart from each other in the front-to-back direction of the unit. The relationship between each exhaust port and the equipment inside the unit case 10 will be explained later.

[0022] The exterior cover 15 is a component that covers the tray 11 from above and has a front vertical wall portion (first vertical wall portion) 15A facing the front of the vehicle, a rear vertical wall portion (second vertical wall portion) 15B facing the rear of the vehicle, a top surface portion 15E connecting the upper end of the front vertical wall portion 15A and the upper end of the rear vertical wall portion 15B, and a left vertical wall portion 15D connecting the left end of the front vertical wall portion 15A and the left end of the rear vertical wall portion 15B, facing outward in the unit width direction. The lower and right sides of the exterior cover 15 are open. Each of the vertical wall portions 15A, 15B, and 15D of the exterior cover 15 is fixed to the side wall 13 of the tray 11, etc.

[0023] Furthermore, a roughly rectangular first air guide hole 16a is provided on the left side of the front vertical wall portion 15A of the outer cover 15, and a roughly square second air guide hole 16b is provided on the left side of the rear vertical wall portion 15B of the outer cover 15. The first air guide hole 16a and the second air guide hole 16b are through holes that allow air from outside the unit to be drawn into the inside of the unit, and the second air guide hole 16b is positioned to the left of the first air guide hole 16a. Also, inside the outer cover 15, a first electric fan 31 is positioned opposite the first air guide hole 16a, and a second electric fan 32 is positioned corresponding to the second air guide hole 16b. As shown in Figure 5, the rotating shaft 31a of the first electric fan 31 has a rotating shaft 31a that extends in the front-rear direction of the unit. Furthermore, the second electric fan 32 is composed of two fans (the second electric fan 32a on the left and the second electric fan 32b on the right) arranged adjacent to each other in the unit width direction (left-right direction). Also, a handle 19 is provided in the center of the rear vertical wall 15B in the left-right direction, to the right of the first air guide hole 16a. By pulling this handle 19 toward the rear of the vehicle, the power generation unit 1 can be removed from the vehicle body.

[0024] As shown in Figure 6, the power generation engine 20 is fixed to the bottom 12 of the unit case 10 via first to third mounts 41, 42, and 43. In this example, the power generation engine 20 is located at the front of the bottom 12 of the tray 11, approximately in the center in the left-right direction. As shown in Figures 5 and 7 to 9, the power generation engine 20 of this embodiment includes a cylinder block 21 in which a piston (not shown) is housed, a cylinder head 21d, a cylinder cover 22, and a crank section 23 that houses a crankshaft 30a.

[0025] The cylinder block 21 is housed inside the cylinder cover 22 shown in Figure 7 and extends perpendicular to the longitudinal direction (left-right direction) of the crank section 23. In this example, the cylinder block 21 is inclined upward as it approaches the rear of the vehicle. The outer shape of the cylinder block 21 is, for example, a roughly rectangular parallelepiped extending along the front-rear direction of the unit. A cylinder liner 21b is provided inside the cylinder block 21. The cylinder liner 21b is cylindrical and extends in the front-rear direction of the unit, and the piston 21e is configured to reciprocate within the cylinder liner 21b. In addition, a plurality of heat dissipation fins 21a are provided on the outer surface of the cylinder block 21. The heat dissipation fins 21a protrude outward from the outer surface of the cylinder block 21 and extend, for example, perpendicular to the longitudinal direction of the cylinder block 21.

[0026] The cylinder cover 22, which houses the cylinder block 21, is connected to a fan cowl 40, which will be described later. As shown in Figures 5 and 9, the cylinder cover 22 extends in the front-rear direction of the unit, and the front part of the cylinder cover 22 is connected to the rear surface of the crank section 23. The inner wall surface of the cylinder cover 22 is spaced apart from the tips of the heat dissipation fins 21a of the cylinder block 21. Cooling air can flow through this gap. The fan cowl 40 is connected to the side of the cylinder cover 22. That is, the heat dissipation fins 21a are cooled by the cooling air supplied from the fan cowl 40.

[0027] As shown in Figure 5, the crank section 23 is located in the front of the cylinder block 21 in the front-rear direction of the unit, and in the middle of the unit width direction (approximately the center in this example) on the rear side of the bottom 12 of the tray 11. The crank section 23 extends in the unit width direction, and a crankshaft 30a extending in the unit width direction is located inside the crank section 23. The crankshaft 30a is connected to the piston 21e by a connecting rod 21f (Figure 7).

[0028] Next, the fan cowl 40 will be described. The fan cowl 40 has a passage through which air drawn in by the second electric fan 32 flows. Cooling air for cooling the cylinder block 21 and the like flows through this passage. The fan cowl 40 has openings at the rear and on the right side, and the opening on the right side is connected to the cylinder cover 22. The rear opening is positioned opposite the second electric fan 32.

[0029] Here, the first to third mounts 41, 42, and 43 will be described. As shown in Figure 6, the first mount 41 is located on the outer side in the unit width direction on the front side of the bottom 12 of the tray 11, and supports the lower left side of the generator 30 via a bracket (not shown). The second mount is located in the middle of the unit width direction on the front side of the bottom 12 of the tray 11, and supports the lower part of the crank section 23 via a bracket. The third mount 43 is located behind the second mount 42 in the vehicle, and supports the cylinder cover 22 that covers the cylinder block 21 via a bracket.

[0030] Next, the generator 30 will be described. As shown in Figures 5 to 7, the generator 30 is a device that extends in the unit width direction and is fixed to the bottom 12 of the tray 11, which is located on the left side of the crank section 23 in the unit width direction, via a bracket and a first mount 41 (Figure 7). The generator 30 is also positioned on the left side of the crank section 23 in the unit width direction, and the front end of the generator 30 is located near the front end of the tray 11 and near the front wall of the outer cover 15. Inside the generator 30 is a rotating shaft 30a that extends in the unit width direction, and the left side of the crankshaft is connected to the rotating shaft 30a via a coupling 30b, etc. The generator 30 generates electricity when the rotating shaft 30a rotates due to the drive of the power generation engine 20. Also, as shown in Figures 6 and 8, the generator 30 is connected to cooling pipes 47a, etc., through which cooling water (coolant) that flows through the radiator 47 flows.

[0031] As shown in Figures 6 and 8, the inverter 35 is positioned above the crank section 23, in the front-to-back direction of the unit, and on the front side of the cylinder cover 22, via a bracket such as a base. The inverter 35 is also provided with a cooling water tank 35a. The cooling water tank 35a is located, for example, below the main body of the inverter 35. A cooling pipe 47a through which cooling water flows is connected to the cooling water tank 35a. The inverter 35 is cooled when the cooling water flowing inside the cooling pipe 47a flows into the cooling water tank 35a.

[0032] Next, the fuel tank 24 will be described. The fuel tank 24 is filled with fuel to drive the power generation engine 20. The fuel tank 24 has an overall shape that is roughly rectangular and is located to the right of the crank section 23. The fuel tank 24 and the generator 30 are arranged so as to straddle the crack section 23. The fuel tank 24 has a fuel filler port 24a at its top. Although detailed illustrations are omitted, the fuel tank 24 has a front wall section 24A facing the front of the vehicle, a rear wall section 24B facing the rear of the vehicle, an inner wall section 24C facing the inside (left side) in the unit width direction, and an outer wall section 24D facing the outside (right side) in the unit width direction.

[0033] The muffler 25 is arranged in a left-right direction on the cylinder block 21 of the power generation engine 20 within the unit case 10. Exhaust gas from the power generation engine 20 flows through the inside of the muffler 25 and is then exhausted to the outside of the unit. The muffler 25 has a muffler body 26A, a tail end 26B, and a muffler cover 28 that covers the muffler body 26A. As shown in Figure 9, the muffler body 26A is cylindrical in shape extending in the vertical direction and has a cross-sectional shape consisting of an arc portion and a straight portion, as shown in Figure 5. The muffler cover 28 is a member that covers the muffler body 26A and has a rear wall portion 28B that extends downward from the upper rear end toward the bottom 12 of the tray 11, and an outer wall portion 28D that extends downward from the upper end in the unit width direction of the muffler 25 toward the bottom 12 of the tray 11. Furthermore, the upper part of the muffler cover 28, the rear wall portion 28B, and the outer wall portion 28D constitute part of the outer wall of the unit case 10.

[0034] The tail end 26B is connected to the lower part of the muffler body 26A, and is configured so that exhaust gas that has flowed through the inside of the muffler body 26A is exhausted to the outside of the unit. The tail end 26B is located inside the first exhaust port 12a when the bottom 12 of the unit case 10 is viewed from the outside of the unit (viewed downwards from the unit).

[0035] Here, the relationship between the exterior cover 15, the fuel tank 24, and the muffler cover 28 will be explained. The front wall portion 24A of the fuel tank 24 is positioned to connect to the front vertical wall portion 15A of the exterior cover 15. That is, the front vertical wall portion 15A of the exterior cover 15 and the front wall portion 24A of the fuel tank 24 constitute the front outer wall of the power generation unit 1. In addition, the outer wall portion 24D of the fuel tank 24 and the outer wall portion 28D of the muffler cover 28 are connected, and the outer wall portion 24D of the fuel tank 24 and the outer wall portion 28D of the muffler cover 28 constitute the outer outer wall of the unit case 10 in the unit width direction.

[0036] Next, the cooling system of this embodiment will be described. The cooling system includes a first cooling system that cools the area around the equipment arranged within the unit, and a second cooling system that cools the cylinder block 21 and the like. Each cooling system will be described below.

[0037] In this embodiment, as described above, the unit case 10 is provided with a first exhaust port 12a, which is located within the unit case 10 at a position where it is at its maximum distance from the first electric fan 31, and a first cooling system (air guide path) through which air flows is provided between the first electric fan 31 and the first exhaust port 12a.

[0038] The first cooling system has an air guide path formed between the first air guide hole 16a and the first exhaust port 12a, and for example, the gap formed between adjacent unit components becomes part of the air guide path. For example, the gap 51 formed between the power generation engine 20 and the fuel tank 24 shown in Figures 5 and 7 to 10, the gap 52 formed between the muffler 25 and the fan cowl 40, and the gap 53 formed between the muffler 25 and the fuel tank 24 are all part of the air guide path of the first cooling system. Therefore, the air guide path constituting the first cooling system in this embodiment is branched into multiple paths.

[0039] When the first electric fan 31 is driven, cooling air flows into the unit from the first air intake 16a. At this time, the cooling air is first blown onto, for example, the front of the crank section 23 of the power generation engine 20, and then dispersed in all directions within the unit. That is, the cooling air blown onto the front of the crank section 23 is branched into multiple paths, including the gaps 51, 52, and 53 mentioned above, and flows through each of the branched paths. The cooling air that has flowed through the multiple paths is exhausted to the outside of the unit from the first exhaust port 12a.

[0040] In this way, by providing the first cooling system, the air blown by the first electric fan 31 is first directed onto the crank section 23, ensuring reliable cooling of the crank section 23 and the oil pan section, etc. Furthermore, as the air is blown onto the power generation engine 20, the cooling air is dispersed in all directions within the unit case 10, making it easier to guide the air into the unit. In addition, since the first exhaust port 12a is located at the position furthest from the first electric fan 31 within the unit case 10, it is possible to allow the cooling air to flow over a wide area (almost the entire) within the unit case 10.

[0041] Furthermore, in this embodiment, as described above, the bottom 12 of the unit case 10 is rectangular in shape, extending along the longitudinal direction of the crank section 23, the first exhaust port 12a is located at the corner of the bottom 12, and a muffler 25 through which exhaust gas exhausted from the power generation engine 20 flows is located inside the unit case 10. As described above, the tail end 26B of the muffler 25 is located inside the first exhaust port 12a when the bottom 12 of the unit case 10 is viewed from the outside of the unit (viewed downwards from the unit). In this example, the end (lower end) of the tail end 26B is located inside the first exhaust port 12a. That is, the opening edge of the first exhaust port 12a is located around the lower end of the tail end 26B. Note that the lower end of the tail end 26B may be located slightly above the first exhaust port 12a in the vertical direction of the unit. In this case, the lower end of the tail end 26B is positioned opposite the first exhaust port 12a. Alternatively, the lower end of the tail end 26B may protrude slightly outside the unit from the first exhaust port 12a. In this case, it is preferable that the lower end is positioned so as not to interfere with any components on the outside of the unit.

[0042] Since exhaust gas from the power generation engine 20 flows through the muffler 25, the area around the muffler 25 becomes hotter than other areas within the unit case 10. By arranging the first exhaust port 12a as described above, it is possible to efficiently discharge the hot air to the outside of the unit. Furthermore, since the first exhaust port 12a is provided around the tail end 26B of the muffler 25, that is, surrounding the tail end 26B, the energy of the exhaust flow from the muffler 25 draws out the air around the muffler 25. As a result, the above configuration makes it possible to improve exhaust efficiency.

[0043] Furthermore, in this embodiment, the fuel tank 24 is positioned adjacent to the power generation engine 20 in the vehicle width direction, and the outer part of the power generation engine 20 in the vehicle width direction and, for example, the inner wall portion 24C of the fuel tank 24 are positioned opposite each other with a gap between them. That is, a gap 51 is formed between the outer part of the power generation engine 20 and the inner wall portion 24C of the fuel tank 24. This gap 51 constitutes part of the air guide path as described above. Also, the inner wall portion 24C of the fuel tank 24 extends from the rear vertical wall portion 15B, where the first electric fan 31 is provided, toward the first exhaust port 12a. In addition, the fuel tank 24 and the muffler body 26A are positioned with a gap between them in the vehicle longitudinal direction. That is, a gap 52 is formed between the fuel tank 24 and the muffler body 26A, and this gap 52 constitutes part of the air guide path.

[0044] By providing an air guide path around the power generation engine 20 in this manner, it becomes possible to efficiently cool the area around the power generation engine 20, and as a result, it becomes possible to suppress the temperature rise inside the unit. Furthermore, since the system is configured to generate airflow around the fuel tank 24, it also becomes possible to suppress the temperature rise of the fuel tank 24.

[0045] Furthermore, in this embodiment, the second exhaust port 12b is provided at the above-described position on the bottom portion 12. Therefore, in this example, the second exhaust port 12b is located below the generator 30 inside the unit case 10. The power generation engine 20 is located between the second exhaust port 12b and the first exhaust port 12a. Moreover, the opening area of ​​the second exhaust port 12b is set to be smaller than the opening area of ​​the first exhaust port 12a. Here, the opening area of ​​the first exhaust port 12a is represented by the sum of the opening areas of the multiple through-holes that constitute the first exhaust port 12a. The same applies to the opening area of ​​the second exhaust port 12b.

[0046] In the region opposite to the first exhaust port 12a, for example, the region in front of the first exhaust port 12a, the pressure tends to be higher, which reduces the flow velocity of the cooling air and makes it easier for the air to stagnate. In contrast, since the second exhaust port 12b is provided in the region opposite to the first exhaust port 12a (the region in front of the first exhaust port 12a), the pressure in the region opposite to the first exhaust port 12a decreases, making it possible to ensure the flow of cooling air around the generator 30. Furthermore, by setting the opening area as described above, it is possible to gradually lower the pressure from the upstream side to the downstream side within the air guide path of the first cooling system, making it easier for cooling air to flow to the first exhaust port 12a and ensuring cooling performance. In this embodiment, exhaust ports are provided in areas where stagnation is likely, but the main flow of the first cooling system is from the first electric fan 31 towards the first exhaust port 12a.

[0047] In this embodiment, the unit case 10 has a front vertical wall portion (first vertical wall portion) 15A on which the first electric fan 31 is provided, and a rear vertical wall portion (second vertical wall portion) 15B opposite to the front vertical wall portion 15A, and a second electric fan 32 is provided on the rear vertical wall portion 15B. The second electric fan 32 is positioned offset from the power generation engine 20 in a direction away from the muffler 25. In this example, the second electric fan 32 is positioned offset to the left of the cylinder cover 22 of the power generation engine 20. Furthermore, the unit case 10 is provided with a fan cowl 40 through which air drawn in from the second electric fan 32 flows, and a cylinder cover 22 connected to the fan cowl 40 and covering the cylinder block 21 of the power generation engine 20. Furthermore, the cylinder cover 22 has an intake opening 22a into which air drawn in by the second electric fan 32 flows (Figure 5), and an exhaust opening 22b into which air can be exhausted toward the muffler 25 (Figure 9).

[0048] The second cooling system includes a second electric fan 32, a fan cowl 40, and a cylinder cover 22. When the second electric fan 32 is driven, air from outside the unit flows into the fan cowl 40 through the second air intake 16b. The air flowing into the fan cowl 40 flows into the inside of the cylinder cover 22 through the intake opening 22a of the cylinder cover 22. The air circulating inside the cylinder cover 22 undergoes heat exchange with the heat dissipation fins 21a, etc., and the temperature of the air rises. The air whose temperature has risen due to heat exchange is exhausted to the outside of the cylinder cover 22 through the exhaust opening 22b, then circulates around the muffler 25, and is then exhausted to the outside of the unit through the first exhaust port 12a.

[0049] In this way, in the second cooling system, air blown from the second electric fan 32 toward the power generation engine 20 passes around the cylinder block 21, then flows toward the muffler 25, and is discharged from the first exhaust port 12a. Since the second cooling system for cooling the power generation engine 20 is provided independently of the first cooling system, it is possible to effectively cool the power generation engine 20. In addition, since the air that has cooled the power generation engine 20 flows around the muffler 25 while maintaining a predetermined flow velocity, it is possible to actively discharge the air around the muffler 25 toward the first exhaust port 12a. As a result, it becomes easier to discharge the hot air to the outside of the unit, thus improving the cooling efficiency.

[0050] Furthermore, in this embodiment, the muffler body 26A may be surrounded by a heat shield. For example, the muffler cover 28 may be formed from a heat shield. In this case, it is preferable that a gap be formed between the muffler body 26A and the heat shield. By configuring it in this way, the heat shield can generate an airflow around the muffler 25 toward the first exhaust port 12a, thereby ensuring exhaust efficiency.

[0051] Furthermore, in this embodiment, the first mount 41 for fixing the generator 30, the second and third mounts 43 for fixing the power generation engine 20 to the bottom 12, the ignition coil 45 for starting the power generation engine 20, and electrical components such as the inverter 35 are arranged in the air guide path of the first cooling system. By arranging these components in the air guide path, the temperature rise of each device can be suppressed, and performance degradation can be prevented. For example, the third mount 43 in this embodiment is a liquid-filled mount with liquid sealed inside. Therefore, by suppressing the temperature rise of the liquid, performance degradation can be suppressed. In addition, the inverter 35 is cooled by a water-cooling system, but as described above, air flows around the inverter 35, so the temperature rise of the inverter 35 can be suppressed.

[0052] Furthermore, the power generation unit 1 of this embodiment has a radiator 47. The radiator 47 is positioned so as to overlap the right-side second electric fan 32b when viewed from the rear of the unit. This allows the cooling water flowing through the radiator 47 to be cooled by the airflow from the right-side second electric fan 32b. Cooling pipes 47a are connected to the radiator 47, and these cooling pipes 47a are connected to the inverter 35 and the generator 30, etc.

[0053] In this embodiment, the second electric fan 32 is composed of two fans arranged side by side in the unit width direction (left-right direction). The second electric fan 32a on the left cools the oil cooler 48, and the second electric fan 32b on the right blows air into the fan cowl 40 and also cools the radiator 47.

[0054] Furthermore, the power generation unit 1 of this embodiment has an oil cooler 48 for cooling the engine oil. An oil pipe 48a is connected to the oil cooler 48, and this oil pipe 48a is also connected to the power generation engine 20. The oil cooler 48 is located to the left of the second electric fan 32 in the unit width direction. In this example, the second electric fan 32a on the left side is positioned to blow air onto the oil cooler 48. An exhaust pipe 48b is provided on the front side of the oil cooler 48 to guide the air that has cooled the oil cooler 48 downwards. The opening located below the exhaust pipe 48b is positioned opposite the third exhaust port 12c. That is, the air that has cooled the oil cooler 48 flows through the exhaust pipe 48b and is then exhausted to the outside of the unit through the third exhaust port 12c.

[0055] The air that cools the oil cooler 48 is so-called hot air, and it is desirable not to exhaust it into the unit case 10. Therefore, with the above configuration, by arranging the exhaust pipe 48b adjacent to the downstream side (leeward side) of the oil cooler 48, the air can be exhausted to the outside of the unit via the exhaust pipe 48b. This improves the cooling performance of the power generation unit 1. In addition, the air that has undergone heat exchange in the oil cooler 48 can suppress the temperature rise of other cooling systems within the unit case 10, thus maintaining the freedom of layout of the unit components. Furthermore, by curving the exhaust pipe 48b downward, it is possible to shorten the distance between the oil cooler 48 and the bottom of the exhaust pipe 48b in the front-to-back direction of the unit, further reducing the time that hot air remains inside the unit case 10. As a result, it is possible to suppress the temperature rise inside the power generation unit 1.

[0056] The description of this embodiment is illustrative for explaining the present invention and does not limit the invention as described in the claims. Furthermore, the configuration of each part of the present invention is not limited to the above embodiment, and various modifications are possible within the technical scope described in the claims.

[0057] In this embodiment, an example of mounting the power generation unit 1 to the rear of the vehicle is described, but it is not limited to this. For example, it may be detachably mounted to the side of the vehicle. In this case, the front-rear direction of the unit corresponds to the vehicle width direction. Also, for example, the bottom 12 of the tray 11 of the unit case 10 may be arranged in the vertical direction. In this case, in the front-rear direction of the unit in the above embodiment, the first electric fan 31 is preferably located at the top and the second electric fan 32 is preferably located at the bottom with respect to the vehicle's vertical direction.

[0058] Furthermore, in this embodiment, the first exhaust port 12a is provided at the bottom 12 of the tray 11, but is not limited to this. For example, it may be provided at the position furthest from the first electric fan 31, such as the rear vertical wall portion 15B of the outer cover 15 of the unit case 10. Also, in this embodiment, an ECM is arranged at the left end inside the unit case 10, as shown in Figure 6. This ECM may also be configured to be cooled by airflow from the first electric fan 31.

[0059] In addition to the above, the airflow paths of the first cooling system include, for example, the gap formed between the generator 30 and the bottom 12 of the tray 11, the gap formed between the top of the power generation engine and the top surface 15E of the outer cover 15, the gap formed between the cooling water pump and the inverter 35, the gap formed between the bottom of the power generation engine 20 and the bottom 12, and so on. It may also include the path between the second electric fan 32 and the first exhaust port 12a, which flows around the cylinder cover 22 of the power generation engine. [Explanation of Symbols]

[0060] 1. Power generation unit 10 Unit Case 11 trays 12 Bottom 12a First exhaust port 12b Second exhaust port 12c Third exhaust port 13 Side wall 14. Body mounting section 15 Exterior cover 15A Front vertical wall section (first vertical wall section) 15B Rear vertical wall section (second vertical wall section) 15D Left vertical wall section 15E Top section 16a First air guide hole 16b Second air intake 19 Handle 20 Power generation engines 21 Cylinder block 21a Heat dissipation fins 21b Cylinder Liner 21d Cylinder head 21e Piston 21f Connecting Rod 22 Cylinder cover 22a Introduction opening 22b Exhaust opening 23 Crank section 23A Crankshaft 24 fuel tanks 24a Fuel filler cap 24A Front wall 24B Rear wall 24C Inner wall 24D Exterior wall 25 muffler 26A Muffler Body 26B Tail End 28 Muffler Cover 28B Rear wall 28D Exterior wall 30 generators 31. First electric fan 32. Second electric fan 32a Second electric fan on the left side 32b Second electric fan on the right side 35 Inverter 35a Cooling water tank 40 Fan Cowl 41 First Mount 42 Second Mount 43 The third mount 45 Ignition Coil 46 ECM 47 Radiator 47a Cooling piping 48 Oil cooler 48a Oil piping 48b Exhaust pipe 51 Gap 52 Gap 53 Gap

Claims

1. A cooling structure for a vehicle power generation unit comprising a power generation engine having a crank section, a generator connected to the power generation engine, and a unit case housing the power generation engine and the generator, which is detachably attached to a vehicle, The unit case is provided with a first electric fan having a rotating shaft. The rotating shaft and the crank portion are arranged to overlap when viewed from a direction perpendicular to the longitudinal direction of the crank portion. The unit case is provided with a first exhaust port, which is located within the unit case at a position where it is at its maximum distance from the first electric fan. A cooling structure for a vehicle power generation unit, characterized in that an air guide path is provided between the first electric fan and the first exhaust port through which air flows.

2. The bottom of the unit case is rectangular in shape, extending along the longitudinal direction of the crank section, and the first exhaust port is located at the corner of the bottom. A muffler is arranged inside the unit case through which exhaust gas from the power generation engine flows, and the muffler has a muffler body and a tail end. The cooling structure for a vehicle power generation unit according to claim 1, characterized in that the tail end is positioned inside the first exhaust port when the bottom is viewed from the outside of the unit.

3. The unit case includes a fuel tank, which is filled with fuel to drive the power generation engine, and is positioned adjacent to the power generation engine in the vehicle width direction. The outer portion of the power generation engine in the vehicle width direction and the side wall of the fuel tank are positioned opposite each other with a gap between them, and the side wall of the fuel tank extends from the side wall portion where the first electric fan is installed toward the first exhaust port. The cooling structure for a vehicle power generation unit according to claim 2, characterized in that the fuel tank and the muffler body are arranged with a gap between them in the front-rear direction of the vehicle, and the gap constitutes part of the air guide path.

4. A second exhaust port is provided below the generator within the unit case, and the power generation engine is positioned between the second exhaust port and the first exhaust port. The cooling structure for a vehicle power generation unit according to any one of claims 1 to 3, characterized in that the opening area of ​​the second exhaust port is set to be smaller than the opening area of ​​the first exhaust port.

5. The unit case has a first vertical wall portion on which the first electric fan is provided, and a second vertical wall portion opposite to the first vertical wall portion, the second electric fan being provided on the second vertical wall portion, and the second electric fan being positioned offset from the power generation engine in a direction away from the muffler. The unit case is provided with a fan cowl through which air drawn in from the second electric fan flows, and a cylinder case connected to the fan cowl and covering the cylinder block of the power generation engine. The cooling structure for a vehicle power generation unit according to claim 2 or 3, characterized in that the cylinder case has an inlet opening into which air drawn in by the second electric fan flows, and an exhaust opening into which exhaust can be discharged toward the muffler.

6. The muffler body is surrounded by a heat shield, A cooling structure for a vehicle power generation unit according to claim 2 or claim 3, characterized in that a gap is formed between the muffler body and the heat shield.

7. The cooling structure for a power generation unit according to claim 2 or 3, characterized in that the air guide path includes a mount for fixing the power generation engine to the bottom, an ignition coil for starting the power generation engine, and electrical components.

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