Cooling structure for a vehicle power generating unit

Abstract

To improve cooling performance of a power generation unit in a compact layout.SOLUTION: A cooling structure of a power generation unit includes: a radiator 37 connected to a power generator 30 and an inverter 35 through a cooling pipe; electric fans 31, 32 located adjacent to the radiator 37; and an introduction pipe 40 which is disposed between the radiator 37 and a power generation engine 20 and enables air outside the unit to circulate to the power generation engine 20. The introduction pipe 40 is provided with an introduction opening part for introducing air. The radiator 37 is disposed so as to overlap with a part of the introduction opening part and air which has passed through the radiator 37 may flow from the introduction opening part into the introduction pipe 40.SELECTED DRAWING: Figure 5

Description

[Technical Field]

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

[0002] Known electric vehicles that have a battery for driving an electric motor include vehicles equipped with a small power generation unit, as disclosed in Patent Document 1. By installing such a power generation unit and supplying power to the battery or the electric motor, it is possible to extend the cruising range.

[0003] The power generating unit in the above example is removably mounted in a space provided in the lower rear of the vehicle, for example. The power generating unit in this example has a power generating engine, a generator, and electrical components such as an inverter, all of which are housed inside a case.

[0004] By configuring the power generation unit to be removable from the vehicle body in this way, maintenance is improved and the power generation unit can be used independently in a location away from the vehicle. However, since installation space for such a power generation unit is limited, it is required to be configured more compactly and to have a predetermined cooling performance. For example, in Patent Document 1, each device is arranged so that the cooling path for cooling the generator engine and muffler and the cooling path for cooling the inverter, etc. intersect, making the power generation unit more compact while ensuring cooling performance. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2021-41834 Summary of the Invention [Problem to be solved by the invention]

[0006] In such a power generation unit, compactness and cooling performance depend heavily on the layout of the power generation unit's components. In the above example, cooling paths are provided for the multiple unit components that make up the power generation unit, depending on the heat generation amount of each component. The cooling paths are air-cooled, and a fan draws outside air into the cooling paths to cool the target components.

[0007] Specifically, one cooling path is provided with a cooling fan at the end of the crankshaft of the generator engine, which draws cooling air into the cooling path. Because the cooling fan is provided at the end of the crankshaft, it is necessary to form a cooling path starting from the cooling fan. In addition, the other cooling path is provided with an electric fan to cool electrical components such as the inverter.

[0008] In the above example, it is necessary to provide an air guide member to provide a cooling path. Furthermore, there are limitations on the placement of the fan, which reduces the degree of freedom in the layout of the components. Therefore, if one is to obtain sufficient cooling performance through air cooling while maintaining the degree of freedom in the layout of the components that make up the power generation unit, there is room for improvement in the configuration of the above example.

[0009] The present invention has been made to solve the above-mentioned problems, and its purpose is to provide a cooling structure for a vehicle power generation unit that can improve the cooling performance of the power generation unit while ensuring freedom in the layout of the components that make up the power generation unit. [Means for solving the problem]

[0010] In order to achieve the above object, the present invention provides a cooling structure for a vehicle generator unit, comprising: a generator engine, a generator connected to the generator engine, electrical components electrically connected to the generator, and a unit case that houses the generator engine, the generator, and the electrical components and is detachably attached to a vehicle. The cooling structure for a vehicle generator unit further comprises: a radiator connected to the generator and the electrical components via a cooling pipe through which a coolant flows; an electric fan disposed adjacent to the radiator; and an inlet pipe disposed between the radiator and the generator engine and capable of circulating air outside the unit toward the generator engine, the inlet pipe comprising: cold An inlet opening is provided for introducing cooling air, and the radiator is arranged so as to overlap a part of the inlet opening, and cooling air passes through the radiator. the law of nature The escaped air is configured to be able to flow into the introduction pipe from the introduction opening, The inlet opening includes a first inlet opening into which air drawn by the electric fan flows, and a second inlet opening disposed so as to overlap the radiator and into which air that has passed through the radiator flows. . [Effects of the Invention]

[0011] According to the present invention, it is possible to improve the cooling performance of the power generation unit while ensuring the degree of freedom in the layout of the components that make up the power generation unit. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a perspective view showing the appearance of a vehicle power generating unit according to the present invention; [Figure 2] 2 is a plan view schematically showing a generator engine, a generator, and the like arranged in the unit case of FIG. 1. FIG. [Figure 3] 3 is an enlarged plan view showing the electric fan, the radiator, and the inlet pipe of FIG. 2. FIG. [Figure 4] FIG. 3 is a perspective view showing the radiator and the inlet pipe of FIG. 2. [Figure 5] 5 is a rear view of the unit from the rear side with the radiator of FIG. 4 removed. FIG. [Figure 6]3 is a perspective view showing the state in which the cylinder case of the generator engine of FIG. 2 has been removed and the upper part of the inlet pipe has been omitted. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, one embodiment of the cooling structure for a vehicle power generating unit according to the present invention will be described with reference to the drawings (FIGS. 1 to 6). In the drawings, the direction of the arrow Fr indicates the front in the vehicle longitudinal direction (the unit longitudinal direction). In the description of the embodiment, the "front (front end) and rear (rear end)" correspond to the front and rear in the vehicle longitudinal direction (the unit longitudinal direction). Furthermore, the arrows R and L indicate the right and left sides when an occupant looks forward of the vehicle (when looking forward in the unit longitudinal direction).

[0014] The power generation unit 1 for a vehicle according to this embodiment is detachably mounted, for example, under the floor of a luggage space or the like provided at the rear of the vehicle. Although not shown in the drawings, the power generation unit 1 is inserted into the vehicle through an opening provided at the rear of the vehicle and fixed to the rear of the vehicle. In this case, the power generation unit 1 is disposed, for example, between the left and right rear wheels in the vehicle width direction, and is mounted to highly rigid rear side members and rear cross members that constitute the vehicle body frame.

[0015] As shown in FIG. 2, the power generation unit 1 of this embodiment has a power generation engine 20, a generator 30, an inverter (electrical components) 35, and a cooling device, all of which are housed inside a roughly rectangular parallelepiped unit case 10 shown in FIG. 1.

[0016] The cooling device for the power generation unit 1 of this embodiment also includes a first electric fan 31, a second electric fan 32, a radiator 37, cooling piping 38, and an inlet piping 40. In the unit cooling device of this embodiment, the above-mentioned components that make up the device form an air cooling system and a water cooling system. Each cooling system of the cooling device will be described later.

[0017] The power generation unit 1 also has, as other components, a fuel tank (not shown) filled with fuel for driving the power generation engine 20, and a muffler 28 through which exhaust gas discharged from the power generation engine 20 flows and which discharges the exhaust gas to the outside of the power generation unit 1, and these are arranged in close proximity within the unit case 10. The approximate position of the muffler 28 is shown schematically in Figure 2.

[0018] As shown in FIG. 1 , the unit case 10 has a generally rectangular parallelepiped shape overall, and mounting portions 17 for mounting to a vehicle are provided on the outside of the unit case 10. The power generation unit 1 is mounted, for example, to the rear of the vehicle so that the longitudinal direction of the unit case 10 is aligned with the vehicle width direction. In the following description, the longitudinal direction of the power generation unit 1 corresponds to the vehicle width direction and left-right direction, and the short side direction of the power generation unit 1 corresponds to the vehicle front-rear direction. In this embodiment, the front and rear of the power generation unit 1 correspond to the front and rear of the short side direction (unit front-rear direction) of the power generation unit 1, and the left-right direction of the power generation unit 1 (unit width direction) corresponds to the left and right when the power generation unit 1 is facing forward.

[0019] 1, the unit case 10 of this embodiment has a tray 11 and a lid 15. The tray 11 has a rectangular bottom surface (not shown) on which the power-generator engine 20, the generator 30, etc. are installed, and side walls 13 that protrude upward from each end of the bottom surface and extend along the end. In the following description, the longitudinal direction (long side direction) of the bottom surface corresponds to the unit width direction of the power generation unit 1, and the lateral direction (short side direction) corresponds to the unit front-to-rear direction of the power generation unit 1.

[0020] As shown in Fig. 1, the side walls 13 protrude upward from the left and right ends of the unit case 10 and extend along the front-to-rear direction of the unit. In this example, as shown in Fig. 1, the mounting portions 14 are provided on the side walls 13. The mounting portions 14 have rollers or the like for running on rails provided on the vehicle body.

[0021] The lid 15 is box-shaped and covers the tray 11 from above, and is fixed to the side wall 13 of the tray 11. A substantially rectangular air guide hole 16 is provided on the left side of the rear surface of the lid 15. A first electric fan 31 and a second electric fan 32 are arranged inside the lid 15 so as to cover the air guide hole 16. A handle 18 is provided on the right side of the air guide hole 16, in the center of the rear surface in the left-right direction. The power generation unit 1 can be removed from the vehicle body by pulling the handle 18.

[0022] The generator engine 20 is fixed to the bottom of the unit case 10 via a bracket (not shown) and a mount (not shown). In this example, the generator engine 20 is located at the front of the bottom, approximately in the center in the left-right direction. The generator engine 20 of this embodiment has a cylinder block 21 in which a piston (not shown) is disposed, a cylinder head 22, a cylinder head cover 23, and a crankcase 26 that houses a crankshaft (not shown).

[0023] The cylinder block 21 extends perpendicular to the longitudinal direction of the crankcase 26. The cylinder block 21 has an outer shape that is a roughly rectangular parallelepiped extending in the front-to-rear direction of the unit. A cylinder liner (not shown) is provided inside the cylinder block 21. The cylinder liner is cylindrical and extends in the front-to-rear direction of the unit, and the pistons are configured to move back and forth inside the cylinder liner. 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 in a direction perpendicular to the longitudinal direction of the cylinder block 21.

[0024] For example, the multiple heat dissipation fins 21a provided on the upper surface of the cylinder block 21 protrude upward, extend in the unit width direction, and are spaced apart from one another in the unit front-to-rear direction. Similarly, the multiple heat dissipation fins 21a provided on the side surface of the cylinder block 21 protrude in the unit width direction, extend vertically, and are spaced apart from one another in the unit front-to-rear direction.

[0025] The cylinder block 21 is disposed inside a cylinder case 25, which covers the cylinder block 21. As shown in FIG. 2, the cylinder case 25 extends in the longitudinal direction of the unit, and the front of the cylinder case 25 is connected to the rear surface of the crankcase 26. The inner wall surface of the cylinder case 25 is disposed with a gap between it and the tips of the heat dissipation fins 21a. Cooling air can circulate through this gap. An inlet pipe 40, which will be described later, is connected to the side of the cylinder case 25. That is, the heat dissipation fins 21a are cooled by the cooling air supplied from the inlet pipe 40.

[0026] 2, the crankcase 26 is disposed in front of the cylinder block 21 in the front-rear direction of the unit, at approximately the center in the width direction of the unit at the rear of the bottom surface of the tray 11. The crankcase 26 also extends in the width direction of the unit, and a crankshaft extending in the width direction of the unit is disposed inside the crankcase 26. The crankshaft is connected to the pistons by connecting rods (not shown).

[0027] As shown in Fig. 2, the generator 30 is a device extending in the width direction of the unit, and is fixed via a bracket and a mount to the bottom portion located on the left side of the crankcase 26 in the width direction of the unit. The generator 30 is also located on the left side of the crankcase 26 in the width direction of the unit, with the front end of the generator 30 located near the front end of the bottom portion and near the front wall of the lid 15. A rotating shaft extending in the width direction of the unit is located inside the generator 30, and the left side of the crankshaft is connected to this rotating shaft. The generator 30 generates electricity when the rotating shaft rotates as the generator engine 20 is driven.

[0028] As shown in Fig. 2, the inverter 35 is disposed above the crankcase 26 and in front of the cylinder case 25 in the longitudinal direction of the unit via a bracket such as a base. In Fig. 2, the approximate position of the inverter 35 is indicated by a dashed line. The inverter 35 has a main body and a cooling water tank, and a cooling pipe 38 is connected to the cooling water tank. The main body of the inverter 35 is cooled by the cooling water flowing inside the cooling pipe 38 and flowing into the cooling water tank.

[0029] Next, the radiator 37 will be described. The radiator 37 is connected to the generator 30 and the inverter (electrical component) 35 via cooling pipes 38 through which cooling water (coolant) flows. As shown in FIGS. 2 to 4, the radiator 37 of this embodiment is disposed in the rear portion of the unit case 10. The radiator 37 has a substantially rectangular parallelepiped shape extending in the vertical direction, and is disposed so as to face the front-rear direction of the unit. A water supply port 37a through which cooling water can be supplied is provided at the top of the radiator 37.

[0030] 2 and 3, the radiator 37 is disposed adjacent to the longitudinal end of the cylinder block 21 that is farther from the crankcase 26. That is, in this example, the radiator 37 is disposed adjacent to the rear end of the cylinder block 21.

[0031] 2, cooling pipe 38 is connected to the lower part on the right side of radiator 37. Cooling pipe 38 extends to a cooling water tank of inverter 35. Cooling pipe 38 also includes pipe 38a connecting the cooling water tank and generator 30, and pipe 38b connecting generator 30 and radiator 37. The water cooling system is formed by cooling water cooled by radiator 37 circulating through cooling pipe 38.

[0032] Next, the electric fans 31, 32 will be described. As shown in FIG. 1, the power generation unit 1 of this embodiment has a first electric fan 31 and a second electric fan 32, which are arranged side by side in the width direction of the unit as shown in FIGS. 1 and 2. In this example, the second electric fan 32 is arranged to the right of the first electric fan 31. The first electric fan 31 and the second electric fan 32 are also arranged adjacent to the radiator 37. In this example, the second electric fan 32 is arranged adjacent to and rearward of the radiator 37 in the rear direction of the unit. As described above, the first electric fan 31 and the second electric fan 32 are also arranged opposite the air guide holes 16 on the rear surface of the cover 15 of the unit case 10.

[0033] The air cooling system will now be described. The air cooling system of this embodiment has a first electric fan 31, a second electric fan 32, and a fan cowl. In this example, the air cooling system is configured so that the first electric fan 31 and the second electric fan 32 draw air from outside the power generation unit 1 into the unit, cool the unit components that make up the unit, and then exhaust the air to the outside of the unit.

[0034] The fan cowl is composed of an inlet pipe 40 and a cylinder case 25. The inlet pipe 40 will be described below. As shown in FIGS. 2 and 4, the inlet pipe 40 is disposed between the radiator 37 and the generator engine 20, and is configured to allow air outside the unit to flow toward the generator engine 20. As shown in FIGS. 4 to 6, the inlet pipe 40 has inlet openings 41 and 42, a reduced diameter section 43, and a connecting section 45. The radiator 37 is disposed so as to overlap a portion of the inlet openings 41 and 42, and the air that has escaped through the radiator 37 can flow into the inlet pipe 40 from the inlet openings 41 and 42.

[0035] The inlet pipe 40 is disposed in front of the radiator 37 and rear of the crankcase 26 in the longitudinal direction of the unit. The inlet pipe 40 is disposed on the left side of the cylinder case 25. Inlet openings 41, 42 are provided at the rear of the inlet pipe 40. A connecting portion 45 of the inlet pipe 40 is connected to the right side of the cylinder case 25 so as to be fluidly communicable.

[0036] Here, the inlet openings 41, 42 will be described. As shown in FIGS. 4 and 5 , the inlet openings 41, 42 include a first inlet opening 41 and a second inlet opening 42, which are arranged side by side in the width direction of the unit. In this example, the first inlet opening 41 is arranged to the left of the second inlet opening 42. A portion of the air drawn in by the first electric fan 31 and the second electric fan 32 flows into the first inlet opening 41. The first inlet opening 41 is arranged adjacent to the left side of the radiator 37 and has a generally rectangular shape extending in the vertical direction. A right side wall 41a constituting the opening edge of the first inlet opening 41 extends in the vertical direction and is arranged adjacent to the left side of the radiator 37. The first inlet opening 41 is arranged opposite the first electric fan 31. That is, a portion of the air drawn in by the first electric fan 31 flows into the inlet piping 40 from the first inlet opening 41. Another part of the air taken in by the first electric fan 31 flows toward the oil cooler 50 and the like arranged on the left side of the inlet pipe 40 (FIGS. 2 and 3).

[0037] The second inlet opening 42 is positioned to overlap the radiator 37, and air that has passed through the radiator 37 flows in through it. As shown in Fig. 4, the second inlet opening 42 is positioned forward of the first inlet opening 41 in the front-to-rear direction of the unit, and has a generally rectangular shape that extends in the up-down direction. Since the second inlet opening 42 is positioned opposite the radiator 37, the air taken into the unit by the second electric fan 32 passes through the radiator 37, undergoes heat exchange in the radiator 37, and then flows into the inlet piping 40 through the second inlet opening 42.

[0038] As shown in FIGS. 4 and 6 , the inlet pipe 40 bends to the right, forward of the inlet openings 41 and 42, and is connected to the right side of the cylinder case 25. Here, the flow of cooling air in the air cooling system will be described. Air flowing in through the first inlet opening 41 by the first electric fan 31 flows through the inlet pipe 40. Air outside the unit drawn in by the second electric fan 32 is blown toward the radiator 37 and exchanges heat with the radiator 37. After heat exchange in the radiator 37 and passing through the radiator 37, the air flows into the second inlet opening 42 and merges with the air flowing in through the first inlet opening 41. The merged air passes through the inlet pipe 40 and is blown toward the cylinder block 21. The air blown toward the cylinder block 21 exchanges heat with the outer surface of the cylinder block 21, the heat dissipation fins 21 a, and the like, before flowing into the muffler 28 and being exhausted to the outside of the power generating unit 1.

[0039] In this embodiment, the first electric fan 31 is adjacent to the radiator 37, so that the coolant flowing through the radiator 37 can be constantly cooled. In this case, the electrical components such as the inverter 35 connected to the radiator 37 are constantly cooled, improving the cooling efficiency.

[0040] Furthermore, the air that has undergone heat exchange in the radiator 37 and passed through the radiator 37 is used to cool the cylinder block 21. The air that has undergone heat exchange in the radiator 37 is hotter than the air outside the unit, but is lower in temperature than the cylinder block 21, and therefore can be used as cooling air to cool the cylinder block 21. In other words, according to this embodiment, the air taken in by the electric fans 31, 32 is not wasted, and this air can be used to effectively cool the unit components that make up the power generation unit 1. Furthermore, because the electric fans 31, 32 are located near the rear surface of the lid 15, there is greater flexibility in the layout of the components that make up the cooling system.

[0041] 5, the present embodiment is provided with the first inlet opening 41 and the second inlet opening 42, so that the air flowing in from the different inlet openings 41, 42 joins together inside the inlet pipe 40, causing the air flow to become turbulent inside the inlet pipe 40. Furthermore, the air taken in by the second electric fan 32 is deflected by passing through the radiator 37, which makes it easier for the air to mix with the air outside the unit that flows in from the first electric fan 31.

[0042] By mixing the air outside the unit with the air that has passed through the radiator 37, the temperature of the air that has exchanged heat in the radiator 37 drops, and the temperature of the air blown onto the cylinder block 21 can be made lower than the temperature of the air that has exchanged heat in the radiator 37. As a result, the cylinder block 21 can be cooled more efficiently, and the cooling performance of the generator engine 20 is improved.

[0043] As described above, the inlet pipe 40 of this embodiment extends in the direction from the radiator 37 toward the generator engine 20 (the front-to-rear direction of the unit), and is configured so that air flows along this direction. The reduced diameter section 43 of the inlet pipe 40 of this embodiment is located closer to the generator engine 20 than the inlet openings 41, 42, and has a flow path cross-sectional area that is smaller than the opening area of ​​the inlet openings 41, 42. When the reduced diameter section 43 is viewed from the inlet openings 41, 42, the reduced diameter section 43 overlaps with the first inlet opening 41 and the second inlet opening 42.

[0044] The reduced diameter portion 43 is disposed between the introduction openings 41, 42 and the crankcase 26 in the front-to-rear direction of the unit. In this embodiment, the distance between the reduced diameter portion 43 and the crankcase 26 is smaller than the distance between the reduced diameter portion 43 and the first introduction opening 41.

[0045] The provision of the reduced diameter portion 43 allows air to be mixed more effectively. For example, in this embodiment, air from outside the unit that flows in through the first inlet opening 41 and air that flows in through the second inlet opening 42 and passes through the radiator 37 flows from the inlet openings 41, 42 into the reduced diameter portion 43. Therefore, the reduced diameter portion 43 induces mixing of the air that flows in through the different inlet openings 41, 42, allowing the air to be mixed more effectively. This makes it possible to effectively lower the temperature of the air that has passed through the radiator 37, thereby improving the cooling performance of the generator engine 20.

[0046] In this embodiment, an inclined portion 48 is provided on the inner wall surface forming the flow path of the inlet pipe 40, which is inclined toward the center of the flow path cross section from the inlet openings 41, 42 toward the reduced diameter portion 43. The inclined portion 48 in this embodiment is provided on the inner wall surface located between the reduced diameter portion 43 and the first inlet opening 41, and also on the inner wall surface located between the reduced diameter portion 43 and the second inlet opening 42.

[0047] In this example, of the inner wall surfaces located between the reduced diameter section 43 and the first introduction opening 41, the lower inner wall surface slopes upward toward the front in the front-to-rear direction of the unit. The left inner wall surface slopes toward the right toward the front. Similarly, the upper inner wall surface slopes downward toward the front. Of the inner wall surfaces located between the reduced diameter section 43 and the second introduction opening 42, the lower inner wall surface slopes upward toward the front. The right inner wall surface slopes toward the left toward the front, and the upper inner wall surface slopes downward toward the front. In other words, the sloped section 48 slopes gently toward the reduced diameter section 43, and the front portion of the sloped section 48 is smoothly connected to the reduced diameter section 43.

[0048] By providing the inclined portion 48, it is possible to guide the air along the inclined portion 48. This makes it easier to induce air mixing. In addition, by making the flow path cross section gradually smaller, sudden changes in shape, such as steps, on the flow path surface are suppressed. This makes it possible to suppress air pressure loss and reduce a decrease in flow rate.

[0049] For example, air outside the unit drawn in by the first electric fan 31 through the first inlet opening 41 passes through the inclined portion 48 and flows into the reduced-diameter portion 43. Air that has passed through the radiator 37 also passes through the inclined portion 48 and flows into the reduced-diameter portion 43. That is, air flows with low resistance before reaching the reduced-diameter portion 43, so air mixing is likely to occur in the reduced-diameter portion 43. That is, turbulence is likely to occur near the reduced-diameter portion 43. Therefore, in this embodiment, air in the turbulent flow region is more likely to flow into the cylinder case 25 by air flowing through the inclined portion 48. As a result, the temperature of the air inside the inlet pipe 40 can be lowered while suppressing a decrease in the flow rate of air flowing through the inlet pipe 40, making it easier to maintain cooling performance.

[0050] The radiator 37 is disposed adjacent to the longitudinal end of the cylinder block 21 on the side passing from the crankcase 26. In this example, the radiator 37 is disposed adjacent to the rear end of the cylinder block 21 (on the left side of the cylinder head 22 and cylinder head cover 23). The inlet pipe 40 is bent and connected to the right side of the cylinder case 25 as described above. Therefore, when the inlet openings 41, 42 are viewed from the outside, the connecting portion 45 is not visible. Therefore, the arrangement is such that the air outside the unit and the air passing through the radiator 37 collide with the back wall 47 (the inner wall surface located at the front) of the inlet pipe 40 shown in FIG. 6, which enables the air to be mixed more effectively.

[0051] The description of the present embodiment is merely an example for explaining the present invention, and does not limit the invention 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.

[0052] In this embodiment, an example in which the power generation unit 1 is attached to the rear of the vehicle has been described, but this is not limiting. For example, the power generation unit 1 may be detachably attached to the side of the vehicle. In this case, the front-to-rear direction of the unit corresponds to the width direction of the vehicle. Also, for example, the bottom surface of the tray 11 of the unit case 10 may be disposed vertically. In this case, the front-to-rear direction of the unit in the above embodiment corresponds to the up-down direction of the vehicle, and the first and second electric fans 31, 32 are provided at the bottom, and the air intake holes 16 open downward.

[0053] In addition, in this embodiment, the cross section of the flow path between the reduced diameter portion 43 and the introduction openings 41, 42 gradually decreases toward the front because the inclined portion 48 is provided on the inner wall surface, but this is not limited to this. For example, the cross section of the flow path may be reduced by forming a step at a predetermined position. In addition, although the inclined portion 48 in this embodiment is formed in a flat shape, it may also be formed in a curved shape. In addition, the inclined portion 48 may be funnel-shaped so that the cross section of the flow path decreases toward the reduced diameter portion 43. [Explanation of symbols]

[0054] 1 power generating unit 10 unit case 11 Tray 13 Side wall 15 Lid 16 Air guide hole 17 Mounting part 18 Handle 20. Generator engine 21 Cylinder block 21a Heat dissipation fin 22 Cylinder head 23 Cylinder head cover 25 Cylinder case 26 Crankcase 28 Muffler 30 Generator 31 First electric fan 32 Second electric fan 35 inverter 37 Radiator 37a Water inlet 38 Cooling piping 40 Inlet piping 41 First introduction opening 42 Second introduction opening 43 Reduced diameter section 45 Connecting part 47 Back wall 48 Slope 50 Oil cooler

Claims

1. A cooling structure for a vehicle generator unit, the cooling structure comprising: a generator engine; a generator connected to the generator engine; electrical components electrically connected to the generator; and a unit case that houses the generator engine, the generator, and the electrical components and is detachably attached to a vehicle, a radiator connected to the generator and the electrical components via a cooling pipe through which a coolant flows; an electric fan disposed adjacent to the radiator; an inlet pipe disposed between the radiator and the generator engine, for allowing air outside the unit to flow toward the generator engine; The inlet pipe is provided with an inlet opening for introducing cooling air, the radiator is disposed so as to overlap a portion of the inlet opening, and the air that has passed through the radiator is configured to be able to flow into the inlet pipe from the inlet opening, The cooling structure for a vehicle generator unit, characterized in that the inlet opening includes a first inlet opening through which air drawn in by the electric fan flows in, and a second inlet opening arranged to overlap the radiator and through which air that has passed through the radiator flows in.

2. the inlet pipe extends in a direction from the radiator toward the generator engine, and is configured so that air flows along that direction; the inlet pipe has a reduced diameter portion, the reduced diameter portion being located closer to the generator engine than the inlet opening portion and having a flow path cross-sectional area set smaller than the opening area of ​​the inlet opening portion; 2. The cooling structure for a vehicle power generating unit according to claim 1, wherein the reduced diameter portion overlaps the first inlet opening and the second inlet opening when viewed from the inlet opening.

3. 3. The cooling structure for a vehicle power generating unit as described in claim 2, characterized in that a sloped portion is provided on the flow path surface of the inlet pipe, which slopes toward the center of the flow path cross section as it moves from the inlet opening to the reduced diameter portion.

4. The generator engine has a crankcase that houses a crankshaft, and a cylinder block that extends from the crankcase perpendicular to a longitudinal direction of the crankcase, The electric fan is disposed opposite at least a portion of the introduction opening, the inlet pipe extends from the inlet opening toward the crankcase and bends toward a side portion of the cylinder block, 4. The cooling structure for a vehicle power generating unit according to claim 1, wherein the radiator is disposed adjacent to a longitudinal end of the cylinder block that is farther from the crankcase.

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