Cooling structure for a vehicle power generating unit

Abstract

To improve cooling performance of a vehicle power generation unit in a compact layout.SOLUTION: A cooling structure of a vehicle power generation unit includes: an oil pipe 52 which is connected to a power generation engine 20 and in which an oil circulates; an oil cooler 50 which is connected with the oil pipe 52 and cools the oil; cooling pipes 38a to 38d which are connected to a power generator 30 and an inverter 35 and in which a coolant circulates; and a radiator 37 which is connected with the coolant pipes 38a to 38d and cools the coolant. The oil cooler 50 and the radiator 37 are disposed adjacent to each other in a unit case.SELECTED DRAWING: Figure 2

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 arrange an air guide member to provide a cooling path. Moreover, there are limitations on the arrangement of the fan, which reduces the degree of freedom in the layout of the components. Furthermore, in the above example, layout restrictions arise in order to protect the unit components that make up the power generation unit from external forces, etc., so it may be difficult to ensure the cooling performance of the air cooling system alone.

[0009] Therefore, in the above example, in addition to the two air cooling systems, a cooling system that uses a coolant, a so-called water-cooled cooling system, is provided. The water cooling system has a radiator that performs heat exchange to cool the coolant. Heat exchange devices such as radiators require forced air cooling by cooling fans (electric fans), etc., so layout restrictions also arise in terms of their position relative to the electric fans.

[0010] In addition to the cooling system described above, engine oil circulating inside a power-generator engine typically needs to be cooled by an oil cooler or the like. Similar to a radiator, an oil cooler requires forced air cooling using an electric fan or the like. Therefore, if there are multiple heat-exchanging devices that require forced cooling, the layout of these devices will affect cooling performance. Therefore, there is room for improvement in the configuration of the above example when attempting to efficiently cool the components that make up the power-generating unit while ensuring freedom in the layout of each component that makes up the power-generating unit.

[0011] 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]

[0012] 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, an inverter electrically connected to the generator, and a unit case detachably mounted to a vehicle, which houses the generator engine, the generator, and the inverter. The cooling structure for a vehicle generator unit further comprises: an oil pipe connected to the generator engine and through which oil flows, an oil cooler connected to the oil pipe and capable of cooling the oil, a cooling pipe connected to the generator and the inverter and through which coolant flows, and a radiator connected to the cooling pipe and capable of cooling the coolant, wherein the oil cooler and the radiator are arranged adjacent to each other within the unit case. [Effects of the Invention]

[0013] 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]

[0014] [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, a radiator, cooling piping, and the like arranged in the unit case of FIG. 1. FIG. [Figure 3] 2 is a plan view schematically showing an oil cooler, an exhaust pipe, an oil pipe, and the like arranged in the unit case of FIG. 1. FIG. [Figure 4] FIG. 4 is an enlarged plan view showing the electric fan, the radiator, and the inlet pipe of FIGS. 2 and 3 in an enlarged scale. [Figure 5] 2 is a plan view schematically showing the generator engine, fan cowl, and the like arranged in the unit case of FIG. 1. FIG. [Figure 6] 6 is a perspective view showing the state in which the cylinder case of the generator engine of FIG. 5 has been removed and the upper part of the inlet pipe has been omitted. FIG. [Figure 7] 2, 3 and 5 are side views seen from the right side. [Figure 8] FIG. 6 is a perspective view of the generator engine and other components of FIG. 5 as viewed from below. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, one embodiment of the cooling structure for a vehicle power generating unit 1 according to the present invention will be described with reference to the drawings (FIGS. 1 to 8). In the drawings, the direction of the arrow Fr indicates the front in the vehicle longitudinal direction (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 (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).

[0016] The power generation unit 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.

[0017] 2 and 3, the power generation unit 1 of this embodiment has a power generator engine 20, a generator 30, and an inverter 35. The power generation unit 1 of this embodiment also has a first electric fan 31, a second electric fan 32, a fan cowl, a radiator 37, cooling pipes 38a to 38d, an oil cooler 50, an oil pipe 52, and an exhaust pipe 53. These are housed inside a substantially rectangular parallelepiped unit case 10 shown in FIG.

[0018] 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.

[0019] Furthermore, the power generation unit 1 of this embodiment has multiple systems through which media circulate. In this example, it has an air-cooled cooling system, a water-cooled cooling system, and an oil circulation system. Each system will be described later.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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 intake hole 16 is provided on the left side of the rear surface of the lid 15. The air intake hole 16 is a hole that allows air outside the unit to be drawn into the inside of the unit. A first electric fan 31 and a second electric fan 32 are arranged inside the lid 15 so as to face the air intake hole 16. A handle 18 is provided on the right side of the air intake 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.

[0024] 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. As shown in Figures 6 and 8, the generator engine 20 of this embodiment has a cylinder block 21 in which a piston (not shown) is located, a cylinder head 22, a cylinder cover 23, and a crankcase 26 that houses the crankshaft.

[0025] As shown in Figure 6, 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 along 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 along the front-to-rear direction of the unit, and the pistons are configured to reciprocate inside the cylinder liner.

[0026] Additionally, 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 perpendicular to the longitudinal direction of the cylinder block 21. For example, the plurality of 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 plurality of 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.

[0027] The cylinder block 21 is disposed within a cylinder case 25 that constitutes part of the fan cowl, and the cylinder case 25 covers the cylinder block 21, including the heat dissipation fins 21a. As shown in FIG. 5, the cylinder case 25 extends in the longitudinal direction of the engine 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 spaced apart from the tips of the heat dissipation fins 21a. Cooling air can circulate through this space. 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.

[0028] 5, 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).

[0029] The fan cowl of this embodiment is a component that constitutes part of a cylinder cooling system, which will be described later, and is composed of an inlet pipe 40 and a cylinder case 25. Details of the fan cowl and the cylinder cooling system will be described later.

[0030] Next, the generator 30 will be described. As shown in FIG. 2, the generator 30 is a device extending in the unit width direction, and is fixed via a bracket and a mount to the bottom surface portion located on the left side of the crankcase 26 in the unit width direction. The generator 30 is also located on the left side of the crankcase 26 in the unit width direction, and the front end of the generator 30 is located near the front end of the bottom surface portion, near the front wall of the lid 15. A rotating shaft extending in the unit width direction is arranged 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 is rotated by driving the generator engine 20. The generator 30 is also connected to cooling pipes 38a to 38d through which coolant (coolant) flows through a radiator 37.

[0031] As shown in Fig. 2, the inverter 35 is disposed above the crankcase 26 and on the front side of the cylinder case 25 in the front-to-rear direction of the unit via a bracket such as a base. The inverter 35 is provided with a cooling water tank 36. In Fig. 2, the approximate position of the cooling tank 36 is indicated by an imaginary line. The cooling water tank 36 is disposed below the main body of the inverter 35. A first pipe 38a and a second pipe 38b that constitute cooling piping are connected to the cooling water tank 36. The inverter 35 is cooled by the cooling water flowing inside the cooling pipe (first pipe 38a) flowing into the cooling water tank 36.

[0032] Next, the radiator 37 will be described. As described above, the radiator 37 is connected to the generator 30 and the inverter 35 via the cooling pipes 38a to 38d through which the cooling water flows. As shown in Fig. 2, the radiator 37 in this embodiment is disposed in the rear portion of the unit case 10. The radiator 37 has a generally 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 the cooling water can be supplied is provided at the top of the radiator 37.

[0033] The oil cooler 50 is disposed at the rear of the unit case 10 and is connected to the generator engine 20 via an oil pipe 52. In this example, it is disposed adjacent to the left side of the inlet opening 41 of the inlet pipe 40. The oil cooler 50 and the radiator 37 are disposed adjacent to each other within the unit case 10. In this example, they are disposed side by side along the width direction of the unit. The oil cooler 50 and the radiator 37 are disposed opposite the air guide holes 16.

[0034] As described above, the radiator 37 and the oil cooler 50 are components that exchange heat with cooling air, such as outside air. In this embodiment, because they are arranged adjacent to each other, it is possible to consolidate the structure that takes in outside air in one part of the unit case 10. As a result, it becomes easier to layout the components that make up the multiple cooling systems, and it is also possible to 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 1. In other words, it is possible to consolidate the radiator 37 and the oil cooler 50 in a part of the unit where the cooling conditions are better than other parts, thereby achieving compactness and improving cooling efficiency.

[0035] Furthermore, in this embodiment, the radiator 37 and the oil cooler 50 are arranged in parallel in one air inlet 16, which facilitates a compact structure for taking in outside air. For example, the temperatures of the liquids flowing through the radiator 37 and the oil cooler 50 are different, and therefore the cooling performance required is also different. In this example, the oil cooler 50 has a higher temperature than the radiator 37, so the oil cooler 50 requires higher cooling performance than the radiator 37. In this embodiment, the radiator 37 and the oil cooler 50 are arranged in parallel facing the air inlet 16, so that the outside air flowing in through the air inlet 16 hits the radiator 37 and the oil cooler 50 individually, and it is possible to adjust the amount of air introduced depending on the cooling performance required for the radiator 37 and the oil cooler 50. In other words, this structure makes it easy to maintain the cooling performance of the radiator 37 and the oil cooler 50. In addition, air at outside temperature passes through the radiator 37 and oil cooler 50 arranged in parallel in the air guide hole 16 and proceeds along a path, so that the unit case components can be cooled with sufficient cooling temperature.

[0036] Each of the above systems will now be described in detail. First, the oil circulation system will be described. The oil circulation system is a system through which engine oil for the generator engine 20 circulates, and includes an oil cooler 50, oil piping 52, and an oil circulation pump 51. The oil circulation pump 51 is located to the right of the oil cooler 50, forward of the oil cooler 50 in the longitudinal direction of the unit. The oil piping 52 includes a pipe connecting the oil cooler 50 and the oil circulation pump 51, a pipe connecting the oil circulation pump 51 and the generator engine 20, and a pipe connecting the generator engine 20 and the oil cooler 50. The temperature of the engine oil rises inside the generator engine 20. The engine oil with the increased temperature flows through the oil piping 52 and into the oil cooler 50, where it is cooled. The engine oil cooled by the oil cooler 50 is then sent back to the generator engine 20.

[0037] Next, the water-cooled cooling system will be described. The water-cooled cooling system has a radiator 37, cooling pipes 38a to 38d, and a cooling water circulation pump 39. Cooling water flows through the cooling pipes 38a to 38d, and the cooling pipes 38a to 38d are connected to a cooling water tank 36 for the generator 30 and the inverter 35. The cooling pipes 38a to 38d are also connected to the radiator 37. The radiator 37 is disposed adjacent to the air guide hole 16. The cooling water circulation pump 39 is connected to the cooling pipes 38a to 38d. The cooling water circulation pump 39 is preferably configured to be driven by a power source separate from that of the power generation unit 1.

[0038] 2, in this embodiment, 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 cylinder head cover 23 provided at the rear end of the cylinder block 21.

[0039] 2, the cooling pipes 38a to 38d include a first pipe 38a, a second pipe 38b, a third pipe 38c, and a fourth pipe 38d. The first pipe 38a connects the radiator 37 and the cooling water tank 36 of the inverter 35. In this example, the first pipe 38a connects the left side of the radiator 37 and the rear of the cooling water tank 36 of the inverter 35. The second pipe 38b connects the cooling water tank 36 of the inverter 35 and the cooling water circulation pump 39. The third pipe 38c connects the cooling water circulation pump 39 and the generator 30. The fourth pipe 38d connects the generator 30 and the radiator 37. The cooling water delivered from the cooling water circulation pump 39 flows in the following order: the third pipe 38c, the fourth pipe 38d, the radiator 37, the first pipe 38a, the cooling water tank 36, and the second pipe 38b.

[0040] When the water-cooled cooling system of the power generation unit 1 is unified with the above configuration, the performance of each component can be fully demonstrated by supplying cooling water starting from the component with the lowest set temperature. According to this embodiment, the cooling water cooled by the radiator 37 is supplied to the cooling water tank 36 of the inverter 35, then passes through the generator 30 and returns to the radiator 37. Note that when the generator engine 20 is water-cooled, the cooling water that has passed through the generator 30 can be sent to the generator engine 20 and then returned to the radiator 37.

[0041] By configuring the water-cooled cooling system as described above, it is possible to perform intensive cooling of the inverter 35 and the generator 30 covered by the unit case lid 15. The improved cooling effect enables the power generation unit 1 to exhibit stable power generation performance.

[0042] The water-cooled cooling system cools the inverter 35 and the generator 30 in that order with priority. This increases the cooling efficiency, allowing the radiator 37 to be compact, which in turn makes it easier to arrange the radiator 37 inside the unit case 10. Furthermore, because the radiator 37 is adjacent to the air guide holes 16 of the lid 15, the radiator is more easily exposed to outside air, further enhancing the cooling effect.

[0043] Furthermore, power generation performance is generally more stable when the components constituting the power generation unit 1 are cooled. For this reason, it is desirable that the water-cooled cooling system is always in operation. Therefore, it is preferable that the water-cooled cooling system is configured to operate independently of the other unit components. Furthermore, the water-cooled cooling system does not need to be linked to the generator engine 20. Furthermore, the radiator 37 of this embodiment is configured so that air outside the unit that is drawn into the second electric fan 32 is blown directly onto the radiator 37. The relationship between the second electric fan 32 and the radiator 37 will be explained later.

[0044] In this embodiment, a fan cowl is disposed opposite the radiator 37, and air capable of cooling the generator engine 20, particularly the cylinder block 21, flows through the fan cowl. The air passing through the oil cooler 50 is exhausted to the outside of the unit downstream of the oil cooler 50 in the air flow direction. In other words, this embodiment has two air-cooled cooling systems: a cylinder cooling system that cools the cylinder block 21, and an oil cooling system that cools the oil cooler 50. By providing two independent air-cooling systems, the radiator 37 and the oil cooler 50 can be cooled separately, allowing the cooling performance to be set for each air-cooling system. This means that the cooling performance of the generator unit 1 can be optimized.

[0045] The cylinder cooling system and the oil cooler cooling system will be described in detail below. First, the electric fans 31 and 32 constituting each air-cooling system will be described. The first electric fan 31 and the second electric fan 32 are arranged side by side in the unit width direction. 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 arranged adjacent to the radiator 37 and the oil cooler 50. In this example, the second electric fan 32 is arranged adjacent to the rear of the radiator 37 in the unit front-rear direction. As described above, the first electric fan 31 and the second electric fan 32 are arranged opposite the air guide holes 16 on the rear surface of the cover 15 of the unit case 10. By providing the electric fans 31 and 32 in this manner, it is possible to individually set appropriate airflow rates for the radiator 37 and the oil cooler 50.

[0046] By providing the first and second electric fans 31, 32 so as to face the air guide hole 16 on the rear surface of the cover 15, it is not necessary to consider having other unit components take in air from outside the unit, and the degree of freedom in the layout of the unit components can be maintained. Furthermore, the electric fans 31, 32 facilitate cooling of the radiator 37 and oil cooler 50, thereby improving the cooling performance of the power generation unit 1. Furthermore, since the power generation unit 1 is mounted at the rear of the vehicle, the air guide hole 16 is located at the rear end of the vehicle, making it possible to suppress factors that obstruct air guide.

[0047] The cylinder cooling system will now be described. The cylinder cooling system has a first electric fan 31, a second electric fan 32, and a fan cowl. In this example, the cylinder 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 power generation unit 1, and then exhaust the air to the outside of the unit.

[0048] The fan cowl covers a portion of the generator engine 20 and is configured to allow air drawn in by the first and second electric fans 31, 32 to circulate through it. The fan cowl is provided with exhaust holes 25a, 25b that exhaust air that has passed around the generator engine 20. The fan cowl will be described below.

[0049] The fan cowl is made up of an inlet pipe 40 and a cylinder case 25. As shown in Figure 5, the inlet pipe 40 is arranged 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. The inlet pipe 40 also has an inlet opening 41 and a connecting portion 45. The radiator 37 is also arranged to overlap a portion of the inlet opening 41, and the air that has escaped through the radiator 37 can flow into the inlet pipe 40 from the inlet opening 41.

[0050] The inlet pipe 40 is disposed in front of the radiator 37 and rear of the crankcase 26 in the front-to-rear direction of the unit. The inlet pipe 40 is disposed on the left side of the cylinder case 25. An inlet opening 41 is 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 communicated. Here, the air flow path inside the inlet pipe 40 extends forward from the inlet opening 41, curves to the right, and is connected to the left side of the cylinder case 25.

[0051] In this embodiment, an exhaust device is provided downstream in the direction of air flow through the fan cowl, and an exhaust hole is provided in the unit case 10 downstream in the direction of air flow of the exhaust device. In this example, a muffler 28 is provided as the exhaust device. The muffler 28 is located on the right side of the generator engine 20 and extends in the front-to-rear direction of the unit. The muffler 28 is configured to be able to exhaust exhaust gas emitted from the generator engine 20 from the rear end thereof.

[0052] Exhaust holes 25a and 25b are provided in the cylinder case 25 that constitutes the fan cowl. In this example, the exhaust holes 25a and 25b are provided in the lower and right sides of the cylinder head 22, respectively. An exhaust pipe such as an exhaust pipe (not shown) may be attached to the exhaust hole 25b provided in the lower side. Furthermore, the exhaust hole 25a provided in the right side may discharge toward the muffler 28.

[0053] A portion of the air outside the unit drawn in by the first electric fan 31 flows into the inlet pipe 40 through the inlet opening 41 of the inlet pipe 40. A portion of the air outside the unit drawn in by the second electric fan 32 flows directly into the inlet opening 41, while another portion passes through the radiator 37 and then flows into the inlet opening 41 of the inlet pipe 40. By driving the second electric fan 32, outside air is blown onto the radiator 37, thereby cooling the coolant flowing through the radiator 37. The air flowing in through the inlet opening 41 flows through the inlet pipe 40 and into the cylinder case 25. The air flowing into the cylinder case 25 exchanges heat with the surface of the cylinder block 21, the heat dissipation fins 21a, and the like (FIG. 6), thereby raising the temperature of the air. The heated air is then exhausted to the outside of the cylinder case 25.

[0054] Since the temperature of the air that has cooled the radiator 37 has risen, it is desirable not to exhaust it into the unit case 10. Therefore, for example, as shown in FIG. 8, the air may be exhausted from exhaust hole 25b provided on the lower surface of the cylinder case 25, through an exhaust pipe, and to the outside of the unit from exhaust holes provided on the bottom surface of the tray 11. In this embodiment, by providing exhaust holes 25a, 25b in the fan cowl, it is possible to efficiently exhaust air that has been heated by heat exchange to the outside of the unit. Alternatively, the air may be exhausted from exhaust hole 25a provided on the right side of the cylinder case 25 so as to be blown toward the muffler 28.

[0055] By providing a fan cowl to configure a cylinder cooling system, the cylinder block 21 of the generator engine 20 can be effectively cooled, thereby effectively suppressing temperature increases within the power generation unit 1. Typically, when cooling the generator engine 20 with cooling air, a fan is provided, for example, directly connected to the crankshaft so that it rotates in conjunction with the drive of the generator engine 20. In this case, the fan's rotation speed depends on the engine speed. Furthermore, since the position of the fan relative to the engine is determined, limitations are placed on the layout of the unit components. These limitations may hinder a compact layout. In contrast, in this embodiment, the first and second electric fans 31, 32 are independent of the other unit components. Therefore, operating the electric fans 31, 32 can easily cool the radiator 37 and the oil cooler 50 without depending on the engine speed. Furthermore, in this embodiment, the fan cowl is provided with exhaust holes 25a, 25b, which allow air whose temperature has increased due to heat exchange to be efficiently exhausted to the outside of the unit.

[0056] Next, the oil cooling system will be described. The oil cooling system is composed of an oil cooler 50, an exhaust pipe 53, and a first electric fan 31. The exhaust pipe 53 is disposed forward of the oil cooler 50 in the longitudinal direction of the unit. As shown in FIG. 7 , the exhaust pipe 53 has an intake section 53a and an exhaust section 53b. The intake section 53a is disposed opposite the oil cooler 50 and opens rearward in the longitudinal direction of the unit. The exhaust pipe 53 curves downward from the intake section 53a toward the front in the longitudinal direction of the unit. The exhaust section 53b is provided at the bottom of the exhaust pipe 53 and opens downward. The exhaust section 53b is configured to exhaust air flowing inside the exhaust pipe 53 toward the bottom of the vehicle. The exhaust pipe 53 is formed, for example, from a metal material, but may also be formed from a heat shield or the like.

[0057] The air flow in the oil cooling system is as follows: first, air outside the unit is drawn in by first electric fan 31 and blown onto oil cooler 50, thereby cooling oil cooler 50. At this time, the air passing through oil cooler 50 exchanges heat with oil cooler 50, causing the temperature of the air to rise. The air passing through oil cooler 50 flows into intake section 53a of exhaust pipe 53 and flows inside exhaust pipe 53. The air flowing through exhaust pipe 53 is exhausted to the outside of the unit from exhaust section 53b.

[0058] The air that has cooled the oil cooler 50 is so-called hot air, and it is desirable not to exhaust it into the unit case 10. Therefore, with the above-described configuration, by arranging the exhaust pipe 53 adjacent to the downstream side (downwind side) of the oil cooler 50, the air can be exhausted to the outside of the unit through the exhaust pipe 53. This improves the cooling performance of the power generation unit 1. Furthermore, the air that has undergone heat exchange in the oil cooler 50 can be prevented from raising the temperature of other cooling systems within the unit case 10, thereby maintaining flexibility in the layout of the unit components. Furthermore, by curving the exhaust pipe 53 downward, the distance between the oil cooler 50 and the exhaust portion 53b in the front-to-rear direction of the unit can be shortened, thereby further shortening the time that hot air remains within the unit case 10. As a result, it is possible to suppress a temperature rise within the power generation unit 1. Note that in this embodiment, the layout allows the air outside the unit, which is taken in by the first electric fan 31, to be directly blown onto the oil cooler 50, thereby effectively cooling the oil cooler 50.

[0059] Furthermore, according to this embodiment, the cylinder cooling system and the oil cooling system are provided as two mutually independent air cooling systems, and the air that flows in through the air guide holes 16 by the electric fans 31 and 32 to cool the radiator 37 and the oil cooler 50 flows through each air cooling system and is exhausted to the outside of the unit. This prevents the air that has cooled the radiator 37 and the oil cooler 50 and has increased in temperature from remaining inside the unit case 10. As a result, the cooling performance of the power generation unit 1 can be further improved.

[0060] 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.

[0061] 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.

[0062] Furthermore, although the inlet pipe 40 constituting the fan cowl of this embodiment extends forward from the inlet opening 41, curves to the right, and is connected to the cylinder case 25, this is not limitative. For example, the cylinder block 21 may be disposed forward of the inlet opening 41 in the front-to-rear direction of the unit, and the air flowing in from the inlet opening 41 may be circulated forward and blown against the cylinder block 21. In this case, it is possible to reduce flow resistance inside the inlet pipe 40.

[0063] Furthermore, in this embodiment, the radiator 37 and the oil cooler 50 are arranged side by side on the rear surface of the lid 15 so as to be adjacent in the width direction of the unit, but this is not limiting. For example, the radiator 37 and the oil cooler 50 may be arranged so as to be perpendicular to each other at a corner provided at an end of the unit in the width direction. In this case, it is preferable that the air that has passed through the radiator 37 and the oil cooler 50 and has been heated through heat exchange is forced to be exhausted to the outside of the unit immediately after passing through the radiator 37 and the oil cooler 50 via a duct such as an exhaust pipe 53. [Explanation of symbols]

[0064] 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 36 Cooling water tank 37 Radiator 37a Water inlet 38a First Pipe 38b Second piping 38c 3rd pipe 38d 4th Pipe 39 Cooling water circulation pump 40 Inlet piping 41 Introduction opening 45 Connecting part 50 Oil cooler 51 Oil circulation pump 52 Oil piping 53 Exhaust pipe 53a Intake section 53b Exhaust section

Claims

1. A cooling structure for a vehicle generator unit, comprising: a generator engine; a generator connected to the generator engine; an inverter electrically connected to the generator; and a unit case that houses the generator engine, the generator, and the inverter and is detachably attached to a vehicle, an oil pipe connected to the power-generating engine and through which oil flows; an oil cooler connected to the oil pipe and capable of cooling the oil; a cooling pipe connected to the generator and the inverter, through which a coolant flows; a radiator to which the cooling pipe is connected and which is capable of cooling the coolant; Furthermore, 10. A cooling structure for a vehicle generator unit, wherein the oil cooler and the radiator are disposed adjacent to each other within the unit case.

2. The unit case is provided with an air guide hole, 2. The cooling structure for a vehicle generator unit according to claim 1, wherein the oil cooler and the radiator are arranged in parallel and opposite to the air guide hole.

3. a fan cowl disposed opposite the radiator, The fan cowl is configured so that air capable of cooling the generator engine flows inside the fan cowl, 3. The cooling structure for a vehicle generator unit as described in claim 2, characterized in that the air passing through the oil cooler is exhausted to the outside of the unit downstream of the oil cooler in the air flow direction.

4. The oil cooler and the radiator each have 4. The cooling structure for a vehicle generator unit according to claim 1, further comprising an electric fan for drawing air from outside the unit into the unit.

5. 4. The cooling structure for a vehicle generator unit according to claim 3, wherein the fan cowl is provided with an exhaust hole for exhausting air that has passed around the generator engine covered by the fan cowl.

6. an exhaust pipe for exhausting the air to the outside of the unit is provided downstream in the direction of flow of the air passing through the oil cooler; 6. The cooling structure for a vehicle power generating unit according to claim 3, wherein the exhaust pipe has an exhaust portion that can exhaust air downwardly from the vehicle.

Images