JP6791089B2 - Cylinder head cooling device - Google Patents

Description

The present invention relates to a cylinder head cooling device.

As a conventional cylinder head cooling device, for example, a cooling device disclosed in Japanese Patent Application Laid-Open No. 61-110831 (Patent Document 1) is known. The cooling device of Patent Document 1 has a first cooling water passage having a substantially circular cross section extending in a horizontal direction in a partition wall that separates the intake port and the exhaust port in the vicinity of the valve seats of the intake valve and the exhaust valve arranged adjacent to each other. The inner wall surface of the cylinder head between the valve seats is cooled by the cooling water formed and flowing in the first cooling water passage, and the substantially circular cross section extends horizontally in the partition wall between the first cooling water channel and the inner wall surface of the cylinder head. A second cooling water passage is formed, and during high-load operation, the control valve provided in the second cooling water passage is opened to allow cooling water to flow through both the first cooling water passage and the second cooling water passage. Cooling between the sheets.

Jitsukaisho 61-110831

In the cooling device of Patent Document 1, the control valve is opened during high-load operation, cooling water flows into the second cooling water passage, and the cylinder head is cooled by the second cooling water passage, but the first cooling water passage is used. Since the cooling water also flows, the flow velocity of the cooling water flowing through the second cooling water channel formed near the cylinder bore is slower than when the cooling water flows only through the first cooling water channel, and the high temperature part of the cylinder head is efficiently flowed. There was a problem that it could not be cooled.

Therefore, the present invention has been made to solve the above problems, and a cylinder capable of suppressing excessive cooling of the cylinder head during low load operation and sufficiently cooling the cylinder head during high load operation. It is an object of the present invention to provide a cooling device for a head.

The cylinder head cooling device according to the present invention is provided in the cylinder head forming a part of the engine and the first stream in which the cooling water flows so as to cool the high temperature portion in the vicinity of at least one exhaust valve. The path, the second flow path provided on the cylinder head, connected to the first flow path on the upstream side and the downstream side, and the cooling water flows so as to bypass the high temperature portion, and the first flow path and the second flow path. A control valve provided on the inlet side to adjust the flow rate of the cooling water flowing in the first flow path and the second flow path, and a wall surface of the first flow path are formed, and the cooling water is heated to a high temperature by inclining so as to approach the high temperature part. The control valve is equipped with an inclined surface that collides with the part, and the control valve closes when the engine is in high load operation to increase the flow rate of the cooling water flowing in the first flow path compared to when the engine is in low load operation. The valve is opened to increase the flow rate of the cooling water flowing through the second flow path as compared with the high load operation.

The cylinder head cooling device configured in this way comprises a wall surface of the first flow path and includes an inclined surface that causes the cooling water to collide with the high temperature portion by inclining so as to approach the high temperature portion. As a result, the cooling water flowing in the first flow path is guided by the inclined surface and collides with the high temperature portion to take heat from the high temperature portion, so that the cylinder head can be sufficiently cooled. The control valve closes when the engine is in high load operation and increases the flow rate of the cooling water flowing through the first flow path compared to in low load operation. Therefore, during high load operation, the control valve is guided by the inclined surface and collides with the high temperature part. The flow rate of water increases, and the cylinder head can be effectively cooled during high-load operation. When the engine is in low load operation, the valve is opened to increase the flow rate of the cooling water flowing in the second flow path as compared with in the high load operation. As a result, excessive cooling of the cylinder head can be suppressed.

The cylinder head cooling device further includes a water pump that supplies cooling water to the cylinder head, and the flow rates of the cooling water in the first flow path and the second flow path when the engine is operated with the first load are QL1 and QL2. Assuming that the flow rates of the cooling water of the first flow path and the second flow path when operating with a second load larger than the first load are QH1 and QH2, QL1 / QL2 <QH1 / QH2 and the water pump. The opening degree of the control valve may be controlled so that the cooling water flows through the first flow path while the cooling water is sent from. In this case, the ratio of the cooling water in the first flow path increases during operation with a high load (second load) and decreases during operation with a low load (first load). As a result, a large amount of heat can be taken from the high temperature part during high load operation. Since the opening degree of the control valve is controlled so that the cooling water flows in the first flow path while the cooling water is sent from the water pump, the cooling water always flows in the first flow path. Since the total cross-sectional area of the first and second flow paths during low load operation is larger than that when cooling water does not flow to the first flow path during low load (first load) operation, the first flow path and the first flow path are The total pressure loss of the two channels can be reduced. As a result, the workload of the water pump can be reduced and the fuel consumption of the engine can be improved.

A first flow path may be provided between the two exhaust valves. In this case, since the first flow path can take heat from the two exhaust valves, the cylinder head can be efficiently cooled in the first flow path.

The cross-sectional area of the first flow path may become smaller as it approaches the high temperature portion. In this case, the flow velocity of the cooling water that collides with the high temperature portion can be increased. As a result, the high temperature portion can be efficiently cooled.

The cylinder head cooling device may further include a cylinder block and a holding portion sandwiched between the cylinder head and the cylinder block to hold the control valve. In this case, the control valve can be positioned by sandwiching the holding portion between the cylinder head and the cylinder block, so that the cylinder head cooling device can be easily assembled.

According to the present invention, it is possible to provide a cylinder head cooling device capable of sufficiently cooling the cylinder head.

It is a block diagram of the cooling device of a cylinder head in Embodiment 1. FIG. It is a top view of the cooling device of a cylinder head according to Embodiment 1. FIG. It is a schematic diagram of the actuator, the rod and the shaft seen from the direction indicated by the arrow III in FIG. FIG. 5 is a schematic view of a control valve and a shaft used in a cylinder head cooling device according to the first embodiment. It is sectional drawing along the VV line in FIG. 2, and is sectional drawing which shows the arrangement of the control valve at the time of low load operation. FIG. 5 is a cross-sectional view taken along the line VV in FIG. 2 and is a cross-sectional view showing the arrangement of control valves during high-load operation. It is a top view of the cooling device of a cylinder head in Embodiment 2. FIG. It is a perspective view of the control valve used in the cooling device of a cylinder head according to Embodiment 3. It is a side view of the control valve according to Embodiment 3 mounted in an engine.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are designated by the same reference numerals. Their names and functions are the same. Therefore, detailed explanations about them will not be repeated.

(Embodiment 1)
<Explanation of configuration>
FIG. 1 is a block diagram of a cylinder head cooling device according to the first embodiment. The cylinder head cooling device 1 cools the cylinder head in the engine 2. The engine may be either a gasoline engine or a diesel engine. The cylinder head cooling device 1 has a water pump 2.

The water pump 2 has an impeller, and when the impeller rotates, it acts as a pump that applies centrifugal force to the cooling water to send out the cooling water. The impeller may be connected to the output shaft of the engine 3 and rotate with the output shaft. The impeller may be connected to a motor to rotate.

The water pump 2 is provided, for example, in a cylinder block. A cooling water flow path for cooling the cylinder bore is mainly provided in the cylinder block. The cooling water flow path extends from the outer circumference of the cylinder bore toward the cylinder head. The cylinder head inlet 11 is an inlet for cooling water in the cylinder head, and cooling water is supplied from the cylinder block to the cylinder head inlet 11.

A first flow path 101 and a second flow path 102 as a bypass passage are connected to the cylinder head inlet 11. The first flow path 101 passes through the high temperature portion of the cylinder head. The second flow path 102 bypasses the high temperature portion of the cylinder head. The ratio of the flow rates of the first flow path 101 and the second flow path 102 is determined by the opening degree of the control valve 30. The flow rate of the cooling water in the second flow path 102 when the control valve 30 is open is larger than the flow rate of the cooling water in the second flow path 102 when the control valve 30 is closed.

The opening degree of the control valve 30 is determined by the load of the engine. The control valve 30 is closed during high load operation. As a result, a large amount of cooling water is supplied to the first flow path 101, and the high temperature portion 15 can be effectively cooled. The control valve 30 is opened during low load operation. As a result, a large amount of cooling water is supplied to the second flow path 102.

Comparing the total pressure loss of the first flow path 101 and the second flow path 102 between the state in which the control valve 30 is closed and the state in which the control valve 30 is open, the one in which the control valve 30 is open The shapes of the first flow path 101 and the second flow path 102 are determined so that the total pressure loss of the first flow path 101 and the second flow path 102 becomes small.

The first flow path 101 and the second flow path 102 are connected to the cylinder head outlet 19. The cylinder head outlet 19 is an outlet for cooling water in the cylinder head. The cooling water discharged from the cylinder head outlet 19 is introduced into, for example, a radiator. The cooling water introduced into the radiator is cooled and the temperature drops. The cooling water cooled by the radiator is introduced into the water pump 2 again.

FIG. 2 is a plan view of a cylinder head cooling device according to the first embodiment. FIG. 3 is a schematic view of an actuator, a rod, and a shaft seen from the direction indicated by arrow III in FIG.

The actuator 20 is attached to the cylinder head 10. A cover 111 and a packing 112 are interposed between the cylinder head 10 and the actuator 20.

The actuator 20 is driven by, for example, a negative pressure. The rod 21 is connected to the actuator 20. The rod 21 is driven in the linear direction indicated by the arrow 22 by the action of the negative pressure of the actuator 20. The rod 21 penetrates the packing 112 and the cover 111. The vicinity of the tip of the rod 21 is located in the cylinder head 10.

The tip of the rod 21 is engaged with the shaft 23. The shaft 23 is arranged in the cylinder head 10 along the longitudinal direction of the cylinder head 10. A lever-shaped portion 23a is provided at the end of the shaft 23. The lever-shaped portion 23a extends so as to be orthogonal to the longitudinal direction of the shaft 23. One end of the lever-shaped portion 23a is engaged with the tip of the rod 21. The lower end of the lever-shaped portion 23a is fixed to the shaft 23.

In the cylinder head 10, the shaft 23 is held in the cylinder head 10 so that it can rotate in the direction indicated by the arrow 24.

A control valve 30 is attached to the shaft 23. When the shaft 23 rotates, the control valve 30 rotates together with the shaft 23. A plurality of control valves 30 are located in the cylinder head 10 at predetermined intervals.

When the rod 21 moves linearly in the direction indicated by the arrow 22, the linear movement of the rod 21 is transmitted to the lever-shaped portion 23a. One end of the lever-shaped portion 23a moves according to the linear movement of the rod 21. As a result, the other end of the lever-shaped portion 23a rotates the shaft 23 in the direction indicated by the arrow 24. The control valve 30 also rotates according to the rotation of the shaft 23.

The cylinder head 10 is provided with a plurality of injectors 12, a plurality of exhaust valves 13, and a plurality of intake valves 14. The plurality of injectors 12 are for injecting fuel into the combustion chamber. The plurality of injectors 12 are arranged at equal distances from each other. In this embodiment, the cylinder head 10 of an engine that directly injects fuel such as light oil or gasoline into the combustion chamber is shown.

The same number of injectors 12 as the number of cylinders of the engine are provided. When the cylinder head 10 is a port injection type gasoline engine, that is, a cylinder head 10 that injects fuel into the intake port instead of injecting fuel directly into the combustion chamber, it is on the combustion chamber, that is, the exhaust valve 13 and the intake air. No injector 12 is provided between the valves 14.

A plurality of intake valves 14 and exhaust valves 13 are provided so as to surround the injector 12. In this embodiment, two intake valves 14 and exhaust valves 13 are provided for one injector 12, but a larger or smaller number of intake valves 14 and exhaust valves 13 may be provided.

The cylinder head 10 is provided with a cooling water flow path 100. The cooling water flow path 100 is a hollow portion provided in the cylinder head 10. The shaft 23 penetrates the cooling water flow path 100. It is necessary to provide a seal at a portion where the shaft 23 penetrates the cooling water flow path 100 so that the cooling water does not leak to the outside from the cooling water flow path 100.

The cooling water flow path 100 is provided to cool the cylinder head 10 with cooling water as a refrigerant. The heat of the cylinder head 10 can be dissipated by transferring the heat of the cylinder head 10 to the cooling water.

The control valve 30 is fitted into the cooling water flow path 100. An insertion path 104 for inserting the control valve 30 into the cooling water flow path 100 is provided in the cylinder head 10. Since the insertion path 104 is a part of the cooling water flow path 100, it is filled with cooling water. A cover 111 for preventing leakage of cooling water seals the insertion path 104.

When inserting the control valve 30 into the cylinder head 10 and removing the control valve 30 from the cylinder head 10, the control valve 30 is inserted or removed via the insertion path 104 with the cover 111 removed.

The cooling water flow path 100 extends from the control valve 30 toward the exhaust valve 13. The cooling water flow path 100 is branched into two from between the two exhaust valves 13, and the cooling water flow path 100 is configured along the arc on the outer circumference of the exhaust valve 13 and surrounding the injector 12. Adjacent cooling water flow paths 100 merge with each other near the intake valve 14 and pass between the two intake valves 14 of the adjacent cylinders.

FIG. 4 is a schematic view of a control valve and a shaft used in the cylinder head cooling device according to the first embodiment. As shown in FIG. 4, a disk-shaped control valve 30 is fixed to the shaft 23. The shaft 23 passes through the diameter portion of the disk. The control valve 30 is a butterfly valve. When the shaft 23 rotates in the direction indicated by the arrow 24, the control valve 30 also rotates in the direction indicated by the arrow 24.

The shape of the control valve 30 is not limited to the disk shape shown in FIG. 4, and other shapes such as an elliptical plate shape and a rectangular shape may be adopted. The control valve 30 is sized so as not to completely block the cooling water flow path 100. By rotating the control valve 30, the state of the flow of the cooling water flowing in the cooling water flow path 100 can be adjusted.

FIG. 5 is a cross-sectional view taken along the line VV in FIG. 2, which is a cross-sectional view showing the arrangement of control valves during light load operation. As shown in FIG. 5, a hollow cooling water flow path 100 is provided in the cylinder head 10. The cylinder head 10 is placed on the cylinder block. The cooling water that has cooled the cylinder block is introduced into the cooling water flow path 100 from the cylinder head inlet 11 to cool the cylinder head 10.

The partition wall 16 is provided in the cooling water flow path 100. The partition wall 16 divides the cooling water flow path 100 into a first flow path 101 and a second flow path 102. On the upstream side and the downstream side of the partition wall 16, the cooling water flow path 100 has one flow, but the partition wall 16 provides two flows, the first flow path 101 and the second flow path 102.

In the vicinity of the control valve 30 provided in the cooling water flow path 100, the cooling water flow path 100 is branched into a first flow path 101 and a second flow path 102.

Exhaust valves 13 are provided on the front side and the back side of the cross section shown in FIG. Since the high-temperature exhaust passes near the exhaust valve 13, the exhaust valve 13 becomes hot. Therefore, a part of the cylinder head 10 in the vicinity of the exhaust valve 13 becomes a high temperature portion 15. Since the high temperature portion 15 has a higher temperature than the surroundings, it is necessary to intensively cool this portion.

The partition wall 16 is provided with an inclined surface 121. The inclined surface 121 causes the flow of cooling water in the first flow path 101 to collide with the high temperature portion 15. The inclined surface 121 is inclined toward the high temperature portion 15.

The partition wall 16 may be made of the material of the cylinder head 10 and may be integrally formed with the cylinder head 10. The partition wall 16 is composed of a separate member from the cylinder head 10, and may be configured by inserting the separate member into the cooling water flow path 100 in the cylinder head 10. When inserting another member, it is possible to insert the other member from the insertion path 104 or from the cylinder head inlet 11.

The inclined surface 121 is inclined so as to approach the high temperature portion. The inner diameter of the first flow path 101 decreases from the upstream side to the downstream side of the first flow path 101 along the inclined surface 121. The cross-sectional area of the first flow path 101 becomes smaller as it approaches the high temperature portion 15. As a result, pressure loss occurs when the cooling water flows through the first flow path 101.

The second flow path 102 joins the first flow path 101 upstream and downstream. The second flow path 102 is located above the first flow path 101. The distance from the high temperature section 15 to the second flow path 102 is longer than the distance from the high temperature section 15 to the first flow path 101. Therefore, even if the cooling water is passed through the second flow path 102, the effect of cooling the high temperature portion 15 is small. The second flow path 102 is provided in parallel with the first flow path 101, and is mainly provided in a state where it is desired to reduce the flow rate of the cooling water in the first flow path 101, for example, during low load operation, mainly in the second flow path 102. Cooling water is flushed to. Since the second flow path 102 has a small effect of cooling the high temperature portion 15 and acts as a bypass, it is required to reduce the pressure loss rather than improve the cooling performance. Therefore, it is desired that the cross-sectional area is large and the change in the cross-sectional area is small.

During the low load operation shown in FIG. 5, the rotation position of the control valve 30 is determined so as to guide a large amount of cooling water to the second flow path 102. The cooling water introduced from the cylinder head inlet 11 as shown by the arrow 190 is guided by the control valve 30 and directed to the second flow path 102 as shown by the arrow 192. Cooling water also flows in the first flow path 101, but the amount is small.

Since the temperature of the high temperature section 15 does not rise so much during low load operation, if the cooling water is intensively supplied to the high temperature section 15, the temperature of the high temperature section 15 may become too low. Since the second flow path 102 has a sufficient cross-sectional area, the flow velocity of the cooling water decreases as the proportion of the cooling water flowing through the second flow path 102 increases.

FIG. 6 is a cross-sectional view taken along the line VV in FIG. 2, which is a cross-sectional view showing the arrangement of control valves during high-load operation. As shown in FIG. 6, a large amount of fuel is injected into the fuel chamber during high-load operation. Therefore, the amount of heat generated in the combustion chamber increases, and the exhaust gas passing through the exhaust valve 13 becomes hotter. In addition, the flow rate of high temperature exhaust gas also increases. As a result, the temperature of the high temperature portion 15 becomes higher than that during the low load operation. It is necessary to make a large amount of cooling water collide with the high temperature portion 15 to dissipate heat from the high temperature portion. The rotation position of the control valve 30 is determined so as to guide a large amount of cooling water to the first flow path 101.

During high-load operation, the cooling water introduced from the cylinder head inlet 11 is guided by the control valve 30 and guided to the first flow path 101 as shown by the arrow 190 as shown in FIG. The cooling water flows along the inclined surface 121 in the direction indicated by the arrow 191 and collides with the high temperature portion 15. Therefore, the high temperature portion 15 can be cooled intensively. The flow rates of the cooling water of the first flow path 101 and the second flow path 102 during operation with the first load (low load) of the engine 3 are QL1 and QL2, and the second load (high load) larger than the first load. When the flow rates of the cooling water of the first flow path 101 and the second flow path 102 during the operation in the above are QH1 and QH2, QL1 / QL2 <QH1 / QH2, and the first flow while the cooling water is sent from the water pump 2. The opening degree of the control valve 30 is controlled so that the cooling water flows through the path 101.

The cylinder head cooling device 1 is provided on the upstream side and the downstream side of the cylinder head 10, the first flow path 101 in which the cooling water provided in the cylinder head 10 and cooling the high temperature portion 15 in the vicinity of at least one exhaust valve 13 flows. The second flow path 102, which is connected to the first flow path 101 and allows cooling water to bypass the high temperature portion 15, is provided on the inlet side of the first flow path 101 and the second flow path 102, and the first flow path 101 and the second flow path 102 are provided. The control valve 30 that adjusts the flow rate of the cooling water in the flow path 102 and the inclined surface 121 that constitutes the wall surface of the first flow path 101 and inclines so as to approach the high temperature portion 15 so that the cooling water collides with the high temperature portion 15. Be prepared. The control valve 30 closes when the engine 3 is in high load operation to increase the flow rate of the cooling water flowing through the first flow path 101 as compared with the low load operation, and is opened when the engine 3 is in low load operation. The flow rate of the cooling water flowing through the flow path 102 is increased as compared with the case of high load operation.

<Action and effect>
During low load operation, the rotation position of the control valve 30 is determined so that a large amount of cooling water flows through the second flow path 102 as shown in FIG. As a result, the flow velocity in the first flow path 101 becomes small. The flow velocity of a fluid is related to the pressure loss, and according to Darcy-Weisbach's equation, the pressure loss is proportional to the square of the flow velocity. The first flow path 101 is a narrow path in the vicinity of the high temperature portion 15, and the pressure loss can be effectively reduced by reducing the flow velocity in this portion. When the water pump 2 is mechanical, that is, when the impeller of the water pump 2 is connected to the output shaft of the engine and the discharge capacity of the water pump 2 is determined according to the rotation speed of the engine, the discharge capacity of the water pump 2 is determined in the first flow path 101. When the pressure loss is reduced, the torque required to drive the water pump 2 is reduced, so that the ratio of the engine output consumed by the water pump 2 is reduced. As a result, fuel efficiency can be improved. When the water pump 2 is electric, that is, when the impeller of the water pump 2 is driven by a motor, if the pressure loss is reduced, a sufficient amount of cooling water is circulated even if the rotation speed of the motor is reduced. Can be done. As a result, the work of the water pump 2 can be reduced and the fuel consumption can be improved.

Further, since the high temperature portion 15 is not so high during low load operation, the temperature of the high temperature portion 15 does not become too high even if the flow rate of the first flow path 101 decreases.

When a large amount of cooling water is passed through the high temperature portion 15 to supercool the high temperature portion during low load operation, the cooling loss increases. If the amount of heat input from the fuel is Q1, the amount of exhaust heat is Q2, and the amount of work is W, then Q1-Q2 = W. If the high temperature part is supercooled, the amount of exhaust heat Q2 increases, and the amount of work W decreases, that is, the fuel consumption It leads to deterioration. In the above configuration, the high temperature portion is not supercooled, so that the fuel consumption is not deteriorated.

In the cooling device described in Japanese Patent Application Laid-Open No. 61-110831, the cooling water passage between the valve seats is closed during low load operation. Therefore, only one of the two cooling water passages is used during low load operation. On the other hand, in the above-described first embodiment, since the two cooling water flow paths are used during the low load operation, the flow velocity of the cooling water can be reduced. According to Darcy-Weisbach's equation, the pressure loss is proportional to the square of the flow velocity. In the first embodiment, since the first flow path 101 and the second flow path 102 are used during the low load operation, the flow velocity becomes smaller and the pressure loss is reduced as compared with the cooling device described in Japanese Patent Application Laid-Open No. 61-110831. Can be done. As a result, fuel efficiency can be improved.

During high-load operation, as shown by arrow 190, the cooling water introduced from the cylinder head inlet 11 flows along the inclined surface 121 in the direction indicated by arrow 191 and collides with the high temperature portion 15. Therefore, the high temperature portion 15 can be cooled intensively. The flow velocity of a fluid is related to the heat transfer coefficient, and according to Colburn's equation, the heat transfer coefficient is proportional to the 0.8th power of the flow velocity. By increasing the flow velocity around the high temperature portion 15, heat can be efficiently dissipated from the high temperature portion 15. In the cooling device described in Japanese Patent Application Laid-Open No. 61-110831, the cooling water passage used during high-load operation has a cylindrical shape and is not provided with an inclined surface that inclines toward the high-temperature portion. The flow velocity cannot be increased. As a result, it is difficult to increase the heat transfer coefficient.

Since the control valve 30 is a butterfly valve, the cooling water can be effectively guided to the first flow path 101 as compared with the on-off valve of Japanese Patent Application Laid-Open No. 61-110831.

Since the cooling water flow path 100 is provided between the two exhaust valves 13, the heat of the high temperature portion between the two exhaust valves 13 can be reliably dissipated.

(Embodiment 2)
FIG. 7 is a plan view of the cylinder head cooling device according to the second embodiment. As shown in FIG. 7, in the cylinder head cooling device 1 according to the second embodiment, the position where the actuator 20 is provided is different from that of the first embodiment. The second embodiment is different from the cooling device 1 according to the first embodiment in that the actuator 20 is an electric type and the rod 21 can be rotated.

The rod 21 is engaged with the shaft 23, and when the rod 21 rotates, the shaft 23 also rotates. The cover 111 covers two surfaces of the cylinder head 10, that is, a surface through which the rod 21 penetrates the cylinder head 10 and a surface on which the insertion path 104 is provided, and prevents leakage of cooling water from these surfaces. In this embodiment, the cover 111 of the integral body covers the above two surfaces, but the cover 111 may be divided.

In the cylinder head cooling device 1 configured in this way, it is not necessary to provide a link mechanism as in the lever-shaped portion 23a of the first embodiment. As a result, the configuration can be simplified.

Further, the actuator 20 can be provided on the short surface (the surface perpendicular to the output shaft) of the engine.

(Embodiment 3)
FIG. 8 is a perspective view of a control valve used in the cylinder head cooling device according to the third embodiment. As shown in FIG. 8, the control valve 30 according to the first embodiment is fixed to the shaft 23 and rotates together with the shaft 23 in the direction indicated by the arrow 24. The shaft 23 is supported by the support portion 32. The control valve 30 fits into the hole 32a of the support portion 32. The support portion 32 has a plate shape, and the shaft 23 and the control valve 30 are rotatably supported at the end portions thereof. As a structure for rotatably supporting the shaft 23, for example, C-shaped recesses are provided at both ends of the support portion 32 in the longitudinal direction, the recesses are widened to fit the shaft 23 into the recesses, and then the recesses are narrowed. It is possible to adopt a structure.

FIG. 9 is a side view of the control valve according to the third embodiment mounted in the engine. The cooling water flow path 100 is divided into a first flow path 101 and a second flow path 102 by a partition wall 16. Similar to the first embodiment, the first flow path 101 causes the cooling water to collide with the high temperature portion by the inclined surface. The second flow path 102 is a bypass path and is arranged so as to bypass the high temperature portion. A control valve 30 is provided at the inlet of the second flow path 102. One end of the control valve 30 is fixed to the shaft 23. When the shaft 23 rotates in the direction indicated by the arrow 24, the control valve 30 also rotates in the direction indicated by the arrow 24. The flow rate of the cooling water flowing through the second flow path 102 can be adjusted by the position of the control valve 30.

In this embodiment, the control valve 30 is provided only at the inlet of the second flow path 102, but the control valve 30 may be provided at the inlet of the first flow path 101 as well. Control valves 30 may be provided at the inlets of both the first flow path 101 and the second flow path 102.

The cylinder head 10 is placed on the cylinder block 40. The support portion 32 is sandwiched between the cylinder block 40 and the cylinder head 10. A bolt is inserted into the through hole of the cylinder head 10 and the tip of the bolt is screwed into the cylinder block 40, so that the cylinder head 10 is pressed against the cylinder block 40 by the axial force of the bolt. Since this pressing force is applied to the support portion 32 between the cylinder block and the cylinder head 10, the support portion 32 can be positioned at the boundary between the cylinder head 10 and the cylinder block 40.

When the control valve 30 is closed, the control valve 30 and the support portion 32 become one flat plate. The thickness of the control valve 30 and the support portion 32 are equal. The control valve 30 can be cut out from one plate material, and the remaining portion can be used as the support portion 32.

In the cylinder head cooling device 1 configured in this way, the support portion 32, the shaft 23, and the control valve 30 can be easily positioned by sandwiching the support portion 32 between the cylinder block 40 and the cylinder head 10. it can.

When the control valve 30 is closed, the control valve 30 and the support portion 32 form a single flat plate. Therefore, by sandwiching the single flat plate between the cylinder block 40 and the cylinder head 10, the assembling property is improved. Can be improved.

It should be considered that the embodiments disclosed this time are exemplary in all respects and not restrictive. The scope of the present invention is shown by the scope of claims rather than the above description, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

1 Cylinder head cooling device, 2 Water pump, 3 engine, 10 cylinder head, 11 cylinder head inlet, 12 injector, 13 exhaust valve, 14 intake valve, 15 high temperature part, 16 partition wall, 19 cylinder head outlet, 20 actuator, 21 Rod, 23 shaft, 23a lever-shaped part, 30 control valve, 32 support, 32a hole, 40 cylinder block, 100 cooling water flow path, 101 first flow path, 102 second flow path, 104 insertion path, 111 cover, 112 packing , 121 Inclined surface.

Claims (5)

The cylinder head that forms part of the engine and
A first flow path provided in the cylinder head and through which cooling water flows so as to cool a high temperature portion in the vicinity of at least one exhaust valve.
A second flow path provided on the cylinder head, connected to the first flow path on the upstream side and the downstream side, and through which cooling water flows so as to bypass the high temperature portion.
A control valve provided on the inlet side of the first flow path and the second flow path to adjust the flow rate of the cooling water flowing through the first flow path and the second flow path.
The wall surface of the first flow path is provided with an inclined surface that causes the cooling water to collide with the high temperature portion by inclining so as to approach the high temperature portion.
The control valve closes when the engine is in high load operation to increase the flow rate of the cooling water flowing through the first flow path as compared with when the engine is in low load operation, and opens when the engine is in low load operation. A cylinder head cooling device that increases the flow rate of cooling water flowing through two channels compared to during high-load operation. A water pump for supplying cooling water to the cylinder head is further provided, and the flow rates of the cooling water in the first flow path and the second flow path when the engine is operated with the first load are defined as QL1 and QL2. When the flow rates of the cooling water of the first flow path and the second flow path when operating with a second load larger than the first load are QH1 and QH2, QL1 / QL2 <QH1 / QH2, and the above. The cylinder head cooling device according to claim 1, wherein the opening degree of the control valve is controlled so that the cooling water flows through the first flow path while the cooling water is sent from the water pump. The cylinder head cooling device according to claim 1 or 2, wherein the first flow path is provided between the two exhaust valves. The cylinder head cooling device according to any one of claims 1 to 3, wherein the cross-sectional area of the first flow path becomes smaller as it approaches the high temperature portion. The cylinder head cooling device according to any one of claims 1 to 4, further comprising a cylinder block and a holding portion sandwiched between the cylinder head and the cylinder block to hold the control valve.

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