JP2016075257A - Engine oil cooling structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique effective for making a sub-oil tank compact in an engine oil cooling structure for circulating engine oil within an oil tank of an engine in the sub-oil tank and cooling the engine oil.SOLUTION: A sub-oil tank 20 of an engine oil cooling structure according to the present invention includes a tank housing 20a, an inlet port 20d, an outlet port 20e, a first heat radiation plate 21, a second heat radiation plate 22, and an oil flow-down port 24, and is configured so that engine oil introduced into a cooling space 20c of the tank housing 20a through the inlet port 20d flows on an upper surface of the first heat radiation plate 21 in the first direction, flows downward on an upper surface of the second heat radiation plate 22 through the oil flow-down port 24 and flows in the second direction.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a cooling structure for cooling engine oil.

  Conventionally, various technologies for improving the cooling performance of engine oil have been proposed in order to cope with the fact that the oil temperature of the engine oil increases and the thermal deterioration of the oil occurs as the output of the engine increases. For example, a structure in which an oil cooling mechanism is provided in an oil tank (oil pan) at the bottom of the engine housing, a structure in which a dedicated oil cooler is provided in the engine, and the like are known. In this case, there arises a problem that the engine is enlarged by incorporating the oil cooling mechanism, or the product cost is increased by using an expensive oil cooler having a complicated structure. Further, when an oil cooling mechanism is installed in the oil pan of the engine, it is necessary to make the structure strong (such as a heat sink or a thermo valve) because it receives engine vibration. Therefore, in each of the following Patent Documents 1 and 2, an oil cooling structure is provided in which another sub oil tank connected to the engine oil tank is provided, and the engine oil in the oil tank is circulated to the sub oil tank for cooling. Is disclosed. According to the oil cooling structure disclosed in Patent Document 1, the engine oil in the sub oil tank is cooled via the refrigerant and the cooling water. Moreover, according to the oil cooling structure disclosed in Patent Document 2, a plurality of radiating fins provided on the surface of the sub oil tank and a blower fan that blows outside air toward the radiating fins are used in the sub oil tank. Engine oil is cooled. These techniques disclosed in Patent Documents 1 and 2 are effective in realizing a structure for improving the cooling performance of engine oil by using a sub oil tank at a low cost without increasing the size of the engine.

Japanese Patent No. 4495551 JP-A-8-246872

(Problems to be solved by the invention)
However, in the case of the oil cooling structure disclosed in Patent Document 1, since refrigerant and cooling water are used as a medium for cooling engine oil, piping and equipment for flowing the refrigerant and cooling water are required separately. Therefore, problems such as an increase in the number of parts, a complicated structure around the sub oil tank, and an increase in the size of the sub oil tank may occur. Further, in the case of the oil cooling structure disclosed in Patent Document 2, it is necessary to provide a plurality of heat dissipating fins on the surface of the sub oil tank, which causes a problem that the sub oil tank itself increases in size.

  Accordingly, the present invention has been made in view of the above points, and one of the purposes thereof is an engine oil cooling structure in which engine oil in an engine oil tank is circulated to the sub oil tank and cooled. It is to provide an effective technique for reducing the size of the tank.

(Means for solving the problem)
In order to achieve the above object, an engine oil cooling structure according to the present invention cools engine oil in an oil pan of an engine by circulating it through a sub oil tank. The sub oil tank includes a tank housing, an inlet port, an outlet port, a first heat radiating plate, a second heat radiating plate, and an oil flow outlet. The tank housing is configured as a box-shaped housing having a cooling space for cooling engine oil above a storage space for storing engine oil. The inlet port introduces engine oil from the oil pan to the cooling space of the tank housing. The outlet port returns the engine oil stored in the storage space of the tank housing to the oil pan. The first heat radiating plate is provided in the cooling space of the tank housing, extends in the first direction along the oil level of the engine oil in the storage space from one end to the other end on the inlet port side, It is configured as a plate-like heat radiating plate that radiates heat by contacting the wall surface. The second heat radiating plate is provided below the first heat radiating plate in the cooling space of the tank housing, and extends in the second direction opposite to the first direction from the other end side to the one end side of the first heat radiating plate, And it is comprised as a plate-shaped heat sink which thermally radiates by contacting with the inner wall surface of a tank housing. The oil flow outlet allows oil to flow from the upper surface of the first heat radiating plate to the upper surface of the second heat radiating plate. In this case, in the sub oil tank, after the engine oil introduced into the cooling space of the tank housing through the inlet port flows in the first direction on the upper surface of the first heat radiating plate, the oil oil flows to the upper surface of the second heat radiating plate through the oil outlet. It is configured to flow down and flow in the second direction.

  According to such an engine oil cooling structure, the space above the storage space in the tank housing of the sub oil tank is used as a cooling space, and the first heat radiating plate and the second heat radiating plate are arranged in the cooling space. The sub oil tank can be made compact. Further, heat transfer efficiency can be increased by bringing both the first heat radiating plate and the second heat radiating plate into contact with the inner wall surface of the tank housing, and the temperature of the engine oil flowing on the upper surfaces of these heat radiating plates can be reduced in a short time. be able to.

  In the engine oil cooling structure, at least one of the first heat radiating plate and the second heat radiating plate is a heat radiating plate having a quadrangular shape in plan view, and the inside of the tank housing is at least three sides of the four sides of the heat radiating plate. It is preferably configured to contact the wall surface. Thereby, the contact area (heat transfer area) where at least one of the first heat sink and the second heat sink contacts the inner wall surface of the tank housing can be increased, and the heat transfer efficiency can be further increased.

  In the engine oil cooling structure described above, at least one of the first heat radiating plate and the second heat radiating plate has both side surfaces extending along the oil flow direction of the engine oil flowing on the upper surface of the heat radiating plate extending in an uneven shape, It is preferable that the both side surfaces are configured to contact the inner wall surface of the tank housing. Thereby, the contact area (heat transfer area) where at least one of the first heat sink and the second heat sink contacts the inner wall surface of the tank housing can be increased, and the heat transfer efficiency can be further increased.

  In the engine oil cooling structure, the sub oil tank includes a recess for storing the engine oil flowing on the upper surface of the first heat radiating plate, and an oil pipe including an oil passage for flowing the engine oil from the recess to the storage space. When the oil temperature of the engine oil stored in the recess is lower than the predetermined temperature, the control valve is controlled to increase the flow area of the oil flow path of the oil pipe than when the oil temperature is equal to or higher than the predetermined temperature. And preferably. Thus, it is possible to control to reduce the heat dissipation performance when heat dissipation is unnecessary so as not to hinder warm air for increasing the oil temperature early in the engine, and to increase the heat dissipation performance only when heat dissipation is necessary. As a result, it can be prevented that it takes time to warm up the engine.

  In the engine oil cooling structure described above, the control valve opens the oil flow path of the oil pipe when the oil temperature of the engine oil stored in the recess is lower than the predetermined temperature, and when the oil temperature is equal to or higher than the predetermined temperature degree. It is preferably configured as a thermo valve that closes the oil flow path of the oil pipe. In this case, by using a thermo valve as the control valve, it is possible to reduce the product cost by reducing the number of parts and simplifying the structure.

  In the engine oil cooling structure described above, it is preferable that the oil pipe is disposed in the vicinity of the outlet port of the oil pipe. Thereby, the low-temperature oil stored in the recess can be returned to the engine oil pan by bypassing the storage space, and the heat dissipation performance can be more reliably lowered when the engine is warming up.

  In the engine oil cooling structure described above, the sub oil tank is housed together with the engine in the outdoor unit of the gas heat pump air conditioner that circulates the air conditioning refrigerant in the refrigerant circuit by the compressor driven by the engine, and introduces outside air into the outdoor unit. It is preferable to arrange in the vicinity of the outside air inlet for the purpose. Thereby, the sub oil tank can be air-cooled using the outside air introduced from the outside air inlet, and the cooling effect of the engine oil can be enhanced.

  As described above, according to the present invention, the sub oil tank can be made compact in the engine oil cooling structure in which the engine oil in the engine oil tank is circulated to the sub oil tank and cooled.

FIG. 1 is a diagram schematically showing a configuration of a gas heat pump type air conditioner 100 of the present embodiment. FIG. 2 is a diagram schematically showing the structure of the sub oil tank 20 in FIG. FIG. 3 is a perspective view showing the structure of the sub oil tank 20 in FIG. FIG. 4 is a plan view of the sub oil tank 20. FIG. 5 is a view for explaining the state of heat transfer of the engine oil in the sub oil tank 20. FIG. 6 is a perspective view of an internal heat radiating plate 121 which is a modified example of the internal heat radiating plate 21 in FIG. 2. FIG. 7 is a diagram schematically showing the structure of a sub oil tank 120 which is a modified example of the sub oil tank 20. FIG. 8 is a diagram schematically showing the structure of a sub oil tank 220 which is a modified example of the sub oil tank 20.

  Hereinafter, it demonstrates, referring embodiment of this invention.

  As shown in FIG. 1, the gas heat pump type air conditioner (GHP) 100 includes an outdoor unit 10 disposed outside and an indoor unit 30 disposed indoors.

  The main body casing 11 of the outdoor unit 10 is partitioned into a lower engine chamber 11a and an upper heat exchanger chamber 11b with a partition plate 12 therebetween. A plurality of machines including a gas engine 13 using gas as a fuel, a compressor (compressor) 16, a switching valve 17, a sub oil tank 20, and the like are accommodated in the engine chamber 11a. The gas engine 13 includes an oil pan (also referred to as “oil tank”) 13 a for storing engine oil for engine lubrication (hereinafter also simply referred to as “oil”) at the bottom of the housing. The compressor 16 functions to compress and discharge the air-conditioning refrigerant using the gas engine 13 as a drive source. At this time, the air-conditioning refrigerant is discharged from the compressor 16 to the refrigerant circuit (a route returning from the compressor discharge portion of the outdoor unit to the compressor suction portion via the indoor unit). A heat exchanger 18 that performs heat exchange between the air-conditioning refrigerant flowing through the refrigerant circuit and the outside air is accommodated in the heat exchanger chamber 11b.

  During the heating operation, the air-conditioning refrigerant discharged from the compressor 16 flows from the switching valve 17 set to the heating operation mode to the indoor unit 30 and is used for the heating air-conditioning, and then the expansion valve 31, the heat exchanger 18 and It returns to the compressor 16 via the switching valve 17 set to the heating operation mode sequentially. On the other hand, during the cooling operation, the air-conditioning refrigerant discharged from the compressor 16 flows from the switching valve 17 set in the cooling operation mode to the indoor unit 30 via the heat exchanger 18 and the expansion valve 31 in order, thereby cooling After being used for air conditioning, the operation returns from the switching valve 17 set to the cooling operation mode to the compressor 16. Thus, the air-conditioning refrigerant is circulated in the refrigerant circuit between the outdoor unit 10 and the indoor unit 30.

  The sub oil tank 20 is a metal oil tank for cooling oil for engine lubrication, and is connected to an oil pan 13 a of the gas engine 13 via rubber oil hoses 14 and 15. This sub oil tank 20 corresponds to the “sub oil tank” of the present invention. The sub oil tank 20 is disposed in the vicinity of the outside air inlet 11 c formed in the main casing 11. The oil stored in the oil pan 13a of the gas engine 13 is sucked through the strainer during operation of the gas engine 13 and is circulated and supplied to the engine sliding portion to reach a high temperature state. This high-temperature oil is sent to the sub oil tank 20 through the oil hose 14 and is retained and cooled, and the cooled oil is circulated to the oil pan 13a through the oil hose 15. When the exhaust heat fan 19 is driven, outside air is introduced into the engine chamber 11a through the outside air introduction port 11c, and is heated by the heat in the engine chamber 11a. The outside air in the engine chamber 11a further flows into the heat exchanger chamber 11b through a ventilation port 12a formed in the partition plate 12, and is then exhausted to the outside of the outdoor unit 10. When such a flow of the outside air is formed, the outside air in the engine chamber 11a comes into contact with the metal surface of the sub oil tank 20 to dissipate the heat held by the sub oil tank 20, whereby the sub oil tank 20 The oil inside is cooled. In this case, the sub oil tank 20 can be air-cooled using the outside air introduced from the outside air introduction port 11c, and the oil cooling effect can be enhanced. In addition, such a sub oil tank 20 is connected to the oil pan 13a of the gas engine 13 only through the oil hoses 14 and 15, and has a high degree of freedom in arrangement.

  As shown in FIGS. 2 and 3, the sub oil tank 20 includes a storage space 20b for storing oil in a metal box-shaped tank housing 20a, and a cooling space as an upper space of the storage space 20b. 20c. The tank housing 20a corresponds to the “tank housing” of the present invention. An inlet port 20d provided at a portion communicating with the cooling space 20c in the tank housing 20a is connected to the oil hose 14. In addition, an outlet port 20 e provided at a portion communicating with the storage space 20 b in the tank housing 20 a is connected to the oil hose 15. These inlet port 20d and outlet port 20e correspond to the “inlet port” and “outlet port” of the present invention, respectively. For this reason, the high-temperature oil stored in the oil pan 13a of the gas engine 13 is introduced into the cooling space 20c of the tank housing 20a through the inlet port 20d, stored in the storage space 20b of the tank housing 20a, and then through the outlet port 20e. It is returned to the oil pan 13a of the gas engine 13.

  The cooling space 20c of the tank housing 20a is provided with a plurality of plate-like internal heat sinks (hereinafter also simply referred to as “heat sinks”). In the present embodiment, three heat radiating plates 21, heat radiating plates 22, and heat radiating plates 23, which are metal plate members, are arranged in order from the top in the height direction X of the cooling space 20c. As shown in FIG. 3, the heat radiating plate 21 extends in the first direction D1 along the oil level L of oil in the storage space 20b from one end on the inlet port 20d side to the other end. It is comprised so that heat may be radiated by contacting with the inner wall surface of 20a. The heat sink 21 corresponds to the “first heat sink” of the present invention. The heat radiating plate 22 is provided below the heat radiating plate 21 in the cooling space 20c, and extends from the other end side of the heat radiating plate 21 to the one end side in a second direction D2 opposite to the first direction D1. It is configured to dissipate heat by contacting the inner wall surface of the housing 20a. The heat radiating plate 22 corresponds to the “second heat radiating plate” of the present invention. The heat sink 23 is provided below the heat sink 23 in the cooling space 20c, and extends in the third direction D3, which is the same direction as the first direction D1, from the other end side of the heat sink 21 to the one end side. The heat is dissipated by coming into contact with the inner wall surface of the tank housing 20a.

  As shown in FIG. 4, the radiator plate 21 has a quadrangular shape in plan view, and is in metal contact with the inner wall surface of the tank housing 20 a on three sides (three contact surfaces 21 a, 21 b, 21 c) of the four sides, and Between the remaining one non-contact surface (surface that does not contact the inner wall surface of the tank housing 20a) 21d and the inner wall surface of the tank housing 20a, an oil flow port 24 having a square shape in plan view is formed. The oil flow outlet 24 forms a flow path for allowing oil to flow from the upper surface of the heat radiating plate 21 to the upper surface of the heat radiating plate 22. This oil flow-down port 24 corresponds to the “oil flow-down port” of the present invention. Further, the heat radiating plate 21 is inclined and disposed in the form of a lower right shoulder in FIG. 2 so that the height of the non-contact surface 21d is lower than the height of the contact surface 21c.

  The heat radiating plate 22 has a quadrangular shape in plan view, and is in metal contact with the inner wall surface of the tank housing 20a on three sides (three contact surfaces 22a, 22b, 22d) of the four sides, and the remaining one non-contact surface ( Between the inner wall surface 22c of the tank housing 20a and the inner wall surface of the tank housing 20a, an oil flow port 25 having a square shape in plan view is formed. The oil flow down port 25 forms a flow path for flowing oil from the upper surface of the heat radiating plate 22 to the upper surface of the heat radiating plate 23. In addition, the heat radiating plate 22 is inclined and arranged in the form of a left shoulder in FIG. 2 so that the height of the non-contact surface 22c is lower than the height of the contact surface 22d.

  The heat sink 23 has a quadrangular shape in plan view, and is in metal contact with the inner wall surface of the tank housing 20a on three sides (three contact surfaces 23a, 23b, 23c) of the four sides, and the remaining one non-contact surface ( Between the inner wall surface 23d of the tank housing 20a and the inner wall surface of the tank housing 20a, an oil flow opening 26 having a square shape in plan view is formed. The oil flow-down port 26 forms a flow path for flowing oil from the upper surface of the heat radiating plate 23 to the storage space 20b. In this case, the oil flow lowering port 26 is formed at a position spaced apart from the outlet port 20e in the lateral direction Y. Further, the heat dissipating plate 23 is inclined and arranged in the form of a lower right shoulder in FIG. 2 so that the height of the non-contact surface 23d is lower than the height of the contact surface 23c.

  As a result, the three oil outlets 24, 25, and 26 are alternately arranged in the lateral direction Y, and the oil flows while continuously flowing on the three radiator plates 21, 22, and 23 using gravity. An oil heat dissipation path (also referred to as an “oil cooling path” for cooling the oil) for radiating the heat held is formed. In addition, the shape of the oil flow lower ports 24, 25, and 26 in plan view is not limited to a quadrangle, and may be changed to a circle, an ellipse, a triangle, or a polygon as necessary.

  The oil flow in the oil heat radiation path will be described in detail. First, the high-temperature oil introduced into the cooling space 20c of the tank housing 20a is firstly directed with the upper surface of the heat radiating plate 21 toward the oil flow outlet 24 according to the inclination. Flow in direction D1. Thereafter, the oil that has flowed down to the upper surface of the heat radiating plate 22 through the oil flow lowering port 24 is directed toward the oil flow lowering port 25 on the side opposite to the oil flow lowering port 24 in the lateral direction Y according to the inclination of the upper surface of the heat radiating plate 22. Flows in two directions D1. Thereafter, the oil that has flowed down to the upper surface of the heat radiating plate 23 through the oil flow lowering port 25 is directed toward the oil flow lowering port 26 on the side opposite to the oil flow lowering port 25 in the lateral direction Y according to the inclination of the upper surface of the heat radiating plate 23. Flows in three directions D1. That is, the high-temperature oil introduced into the cooling space 20c of the tank housing 20a flows down while the oil flow directions are alternately changed by the three heat radiating plates 21, 22, and 23. The oil that has flowed on the upper surface of the heat sink 23 in the third direction D1 finally flows down to the storage space 20b through the oil flow-down port 26 and is temporarily stored.

  FIG. 5 is referred to for a state in which, for example, high-temperature oil flowing on the upper surface of the heat radiating plate 21 in the oil heat radiating path is radiated. As shown in FIG. 5, the heat possessed by the high-temperature oil is first transmitted to the heat radiating plate 21, and further from the three contact surfaces 21a, 21b, and 21c that are in metal contact with the inner wall surface of the tank housing 20a. It is transmitted to the tank housing 20a. Further, the heat held by the high-temperature oil is also transmitted to the tank housing 20a by directly contacting the inner wall surface of the tank housing 20a. Such heat transfer is the same for the remaining heat sinks 22 and 23, and heat transfer as performed by the heat sink 21 is performed three times in total. At this time, since the tank housing 20a and the three heat radiating plates 21, 22, and 23 are all made of a metal material having high thermal conductivity, even if the sub oil tank 20 is small, high-temperature oil can be supplied in a short time. It becomes possible to cool to a desired low temperature. Further, the tank housing 20a dissipates the heat held by coming into contact with the outside air, and continuously dissipates heat by the flow of the outside air formed by the exhaust heat fan 19 in particular. Thereby, the oil flowing through the oil heat radiation path is continuously cooled.

  On the other hand, the oil that has flowed into the storage space 20b through the oil flow lower port 26 is temporarily stored in the storage space 20b, and then flows sequentially through the outlet port 20e and the oil hose 15 and returns to the oil pan 13a of the gas engine 13. At this time, since the oil flow outlet 26 is in a position opposite to the outlet port 20e in the lateral direction Y, the oil flowing down from the oil flow outlet 26 is sufficiently stirred in the storage space 20b. As a result, it is possible to prevent the oil in the storage space 20b from becoming a high temperature state due to local stagnation and being partially thermally deteriorated.

  According to the sub oil tank 20 configured as described above, the space above the storage space 20b in the tank housing 20a is used as the cooling space 20c, and the three heat radiation plates 21, 22, and 23 are arranged in the cooling space 20c. The sub oil tank 20 can be made compact. Also, heat transfer efficiency can be increased by bringing all three heat sinks 21, 22, and 23 into metal contact with the inner wall surface of the tank housing 20a, and the temperature of oil flowing on the upper surfaces of these heat sinks can be reduced in a short time. Can be made. Particularly, since each of the three heat sinks 21, 22, and 23 is in contact with the inner wall surface of the tank housing 20a at three of the four sides, the contact area where the heat sink and the inner wall surface of the tank housing 20a are in metal contact. The (heat transfer area) can be increased, and the heat transfer efficiency can be increased. Further, by using the sub oil tank 20 for cooling the oil, it is possible to prevent the gas engine 13 from becoming large as in the structure in which the oil cooling mechanism is provided in the oil pan 13a. It is possible to prevent the product cost from becoming high as in the structure of providing the.

  If there is a margin in the heat transfer efficiency, only one of the three heat sinks 21, 22, 23, or only two of the heat sinks are on at least three sides of the four sides. A structure in contact with the inner wall surface of the tank housing 20a may be employed. That is, it is only necessary that at least one of the three heat sinks 21, 22, 23 is in contact with the inner wall surface of the tank housing 20a on at least three sides of the four sides.

  The three heat sinks 21, 22, and 23 having the above-described configuration are all configured as flat metal members. However, the shapes of the heat sinks 21, 22, and 23 can be changed as necessary. A shape change that increases the contact area for transmission is preferred. For this shape change, an internal heat sink 121 as shown in FIG. 6 can be used as at least one of the three heat sinks 21, 22, and 23. In this heat sink 121, both side surfaces (contact surfaces) 121a and 121b along the oil flow direction extend as an uneven zigzag waveform (also referred to as “sawtooth triangular triangle”) or an uneven curved waveform. It is configured as follows. When the heat sink 121 is in metal contact with the inner wall surface of the tank housing 20a at the three contact surfaces 121a, 121b, and 121c, the two contact surfaces 121a and 121b are in contact with the inner wall surface of the tank housing 20a (heat transfer area). ) Can be increased compared to the case of the heat sinks 21, 22, and 23. Further, in the case of the heat radiating plate 121, more hot oil can be retained on the plate than in the case of the heat radiating plates 21, 22, and 23, and thereby the inner wall surface of the tank housing 20 a that is in direct contact with the oil. The contact area (heat transfer area) can also be increased. As a result, the amount of heat transferred from the high temperature oil to the tank housing 20a can be increased as compared with the case of the heat radiating plates 21, 22, 23, and the heat transfer efficiency (heat radiating efficiency) can be further increased.

  By the way, when the gas engine 13 is cooled, the oil temperature is lowered and the viscosity of the oil is increased, so that a mechanical loss in the gas engine 13 is increased. Therefore, the sub-oil tank 20 having the above-described configuration reduces the heat dissipation performance when heat dissipation is not necessary so as not to hinder warm air for increasing the oil temperature at an early stage in the gas engine 13, and only when heat dissipation is required. It is preferable to provide a heat dissipation performance adjustment structure that can increase the heat dissipation (return the heat dissipation performance to normal).

  Therefore, for example, a sub oil tank 120 as shown in FIG. 7 can be used. In FIG. 7, the same elements as those in FIG. 2 are denoted by the same reference numerals, and the description of the same elements is omitted. The sub oil tank 120 includes a heat dissipation performance adjustment structure 110 that can adjust the heat dissipation performance. The heat dissipation performance adjusting structure 110 includes a recess 21e provided in the vicinity of the inlet port 20d in the heat dissipation plate 21 so that oil can be temporarily stored, and extends in the vertical direction so that oil flows from the recess 21e to the storage space 20b. An oil pipe 27 having an existing oil flow path, and a thermo valve 28 provided at the inlet of the oil pipe 27 and serving as a control valve capable of opening and closing the oil flow path of the oil pipe 27 are configured. The thermo valve 28 opens the oil passage when the oil temperature of the oil stored in the recess 21e is lower than a predetermined temperature, and closes the oil passage when the oil temperature is higher than the predetermined temperature. Operate. The recess 21e, the oil pipe 27, and the thermo valve 28 referred to here correspond to the “recess”, “oil pipe”, and “control valve (thermo valve)” of the present invention, respectively.

  According to this heat dissipation performance adjusting structure 110, when low temperature oil flowing from the inlet port 20d to the heat dissipation plate 21 is stored in the recess 21e, the oil flows into the oil pipe 27 according to gravity by opening the thermo valve 28. It flows into the storage space 20b through the oil flow path. In this case, the low temperature oil stored in the recess 21e flows by bypassing all of the three heat sinks 21, 22, 23, and the original heat dissipation function of these heat sinks 21, 22, 23 is not used. When heat radiation is not required, such as during warm air, control can be performed to lower the heat radiation performance. On the other hand, when high-temperature oil flowing from the inlet port 20d to the heat sink 21 is stored in the recess 21e, the oil covers the upper surfaces of the heat sinks 21, 22, and 23 by a normal route by closing the thermo valve 28. Flowing. In this case, it is possible to control to improve the heat dissipation performance only when heat dissipation is necessary. As a result, it is possible to prevent the gas engine 13 from taking time to warm up. Further, by using the thermo valve 28 as a control valve, it is possible to reduce the product cost by simplifying the structure by reducing the number of parts.

  In place of the thermo valve 28, the control is performed so that the oil temperature of the oil stored in the recess 21e is detected by a sensor or the like and the oil flow path of the oil pipe 27 is opened and closed based on the detection result. When the oil temperature is lower than the predetermined temperature based on the detection result of the valve or the oil temperature, control is performed so that the flow area of the oil flow path of the oil pipe is increased compared to the case where the oil temperature is higher than the predetermined temperature It is also possible to use a controlled valve.

  In the heat dissipation performance adjusting structure 110 having the above-described configuration, it is preferable to arrange the pipe outlet of the oil pipe 27 in the vicinity of the outlet port 20e. Thereby, the low temperature oil stored in the recess 21e can be returned to the oil pan 13a of the gas engine 13 by bypassing the storage space 20b, and the heat dissipation performance can be more reliably lowered when the gas engine 13 is warmed up.

  As another modification of the sub oil tank 20 having the above-described configuration, a sub oil tank 220 as shown in FIG. 8 can be used. The sub oil tank 220 is different from the sub oil tank 20 only in a configuration in which a plurality of external heat radiating plates 29 in the form of metal plates are provided on the outer surface of the tank housing 20a. The external heat dissipation plate 29 functions to increase the contact area (heat transfer area) between the tank housing 20a of the sub oil tank 220 and the outside air. According to the external heat radiating plate 29, it is possible to increase the heat radiation amount of heat transferred from the high temperature oil to the outer surface of the tank housing 20a. As a result, thermal deterioration of the oil can be prevented more reliably by further reducing the temperature of the oil in the storage space 20b.

  The present invention is not limited to the above exemplary embodiment, and various applications and modifications are possible. For example, each of the following embodiments to which the above embodiment is applied can be implemented.

  In the above embodiment, the case where the three heat sinks 21, 22, 23 are provided in the sub oil tanks 20, 120, 220 has been described. However, in the present invention, at least two in the sub oil tanks 20, 120, 220 are provided. A structure provided with a heat sink can be employed. Further, the shape of the heat sink in plan view may be a polygon other than a quadrangle.

  In the above embodiment, the case has been described in which the tank housing 20a of the sub oil tanks 20, 120, and 220 and the three radiator plates 21, 22, and 23 are all made of a metal material having high thermal conductivity. Then, when desired cooling performance can be obtained for cooling high-temperature oil, the tank housing and the heat radiating plate can be made of a material other than the metal material. For example, at least one of the four constituent elements of the tank housing 20a and the three heat radiation plates 21, 22, 23 can be made of a resin material having a high thermal conductivity.

  In the above embodiment, the cooling structure for cooling the oil of the gas engine 13 of the gas heat pump air conditioner 100 has been described. However, the present invention is not limited to the cooling structure for cooling the engine of an apparatus other than the gas heat pump air conditioner 100. The invention can also be applied.

  DESCRIPTION OF SYMBOLS 10 ... Outdoor unit, 11 ... Main body casing, 11a ... Engine room, 11b ... Heat exchanger room, 11c ... Outside air introduction port, 12 ... Partition plate, 12a ... Ventilation port, 13 ... Gas engine, 14, 15 ... Oil hose, DESCRIPTION OF SYMBOLS 16 ... Compressor, 17 ... Switching valve, 18 ... Heat exchanger, 19 ... Exhaust heat fan, 20, 120, 220 ... Sub oil tank, 20a ... Tank housing, 20b ... Storage space, 20c ... Cooling space, 20d ... Inlet port , 20e ... outlet port, 21, 22, 23, 121 ... heat sink, 21e ... recess, 24, 25, 26 ... oil outlet, 27 ... oil pipe, 28 ... thermo valve, 29 ... external heat sink, 30 ... indoor 31 ... Expansion valve, 110 ... Heat dissipation performance adjustment structure

Claims (7)

An engine oil cooling structure for cooling the engine oil in the engine oil pan by circulating it through the sub oil tank,
The sub oil tank is
A box-shaped tank housing having a cooling space for cooling engine oil above a storage space for storing engine oil;
An inlet port for introducing engine oil from the oil pan into the cooling space of the tank housing;
An outlet port for returning the engine oil stored in the storage space of the tank housing to the oil pan;
An inner wall surface of the tank housing that is provided in the cooling space of the tank housing and extends in a first direction along an oil level of engine oil in the storage space from one end to the other end on the inlet port side. A plate-like first heat radiating plate that dissipates heat by contacting with,
The cooling space of the tank housing is provided below the first heat radiating plate and extends from the other end side of the first heat radiating plate to the one end side in a second direction opposite to the first direction. And a plate-like second heat radiating plate that radiates heat by contacting the inner wall surface of the tank housing;
An oil flow outlet for allowing oil to flow from the upper surface of the first heat radiating plate to the upper surface of the second heat radiating plate;
Including
After the engine oil introduced into the cooling space of the tank housing through the inlet port flows in the first direction on the upper surface of the first heat radiating plate, it flows down to the upper surface of the second heat radiating plate through the oil flow outlet. An engine oil cooling structure configured to flow in the second direction. The engine oil cooling structure according to claim 1,
At least one of the first heat radiating plate and the second heat radiating plate is a heat radiating plate having a square shape in plan view, and is in contact with the inner wall surface of the tank housing on at least three sides of the four sides of the heat radiating plate. The engine oil cooling structure. The engine oil cooling structure according to claim 1,
At least one of the first heat radiating plate and the second heat radiating plate has both sides extending along an oil flow direction of the engine oil flowing on the upper surface of the heat radiating plate extending in an uneven shape, An engine oil cooling structure configured to come into contact with the inner wall surface of the tank housing. The engine oil cooling structure according to any one of claims 1 to 3,
The sub oil tank includes a recess for storing engine oil flowing on an upper surface of the first heat radiating plate, an oil pipe including an oil passage for flowing engine oil from the recess to the storage space, and the recess. When the oil temperature of the stored engine oil is lower than a predetermined temperature, the control valve is controlled to increase the flow passage area of the oil flow passage of the oil pipe than when the oil temperature is equal to or higher than the predetermined temperature. Including an engine oil cooling structure. The engine oil cooling structure according to claim 4,
The control valve opens the oil passage of the oil pipe when the oil temperature of the engine oil stored in the recess is lower than the predetermined temperature, and when the oil temperature is equal to or higher than the predetermined temperature degree, An engine oil cooling structure configured as a thermo valve for closing the oil passage of an oil pipe. The engine oil cooling structure according to claim 4 or 5,
The oil pipe has an engine oil cooling structure in which an outlet of the pipe is disposed in the vicinity of the outlet port. The engine oil cooling structure according to any one of claims 1 to 6,
The sub-oil tank is housed together with the engine in an outdoor unit of a gas heat pump air conditioner that circulates air-conditioning refrigerant in a refrigerant circuit by a compressor using the engine as a drive source, and is used to introduce outside air into the outdoor unit. Engine oil cooling structure located near the inlet.

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