JP2006242078A - Intake and exhaust valve device for internal combustion engine - Google Patents

Abstract

An intake / exhaust valve device for an internal combustion engine capable of cooling a hollow valve more reliably.
An exhaust valve 27 is formed as a hollow valve 25 having a heat pipe effect. Further, in the vicinity of the valve guide 23, a temperature sensor 40 for detecting the temperature of the valve stem 28 of the exhaust valve 27 is provided via the valve guide 23, and an oil jet 53 for injecting oil to the valve stem 28 is provided. Therefore, when the temperature of the valve stem 28 rises during the operation of the internal combustion engine 1 and reaches a temperature at which dryout may occur in the exhaust valve 27, oil is supplied from the oil jet 53 to the valve stem 28. Can be injected toward As a result, the temperature of the valve stem 28 is lowered, so that the exhaust valve 27 can maintain the heat pipe effect. As a result, the exhaust valve 27 that is the hollow valve 25 can be cooled more reliably.
[Selection] Figure 1

Description

  The present invention relates to an intake / exhaust valve device for an internal combustion engine. In particular, the present invention relates to an intake / exhaust valve device for an internal combustion engine that can cool the hollow valve more reliably.

  A conventional intake / exhaust valve device for an internal combustion engine is provided with a hollow valve having an umbrella portion for communicating an intake port or an exhaust port with a combustion chamber. The umbrella portion constitutes a part of the combustion chamber. Therefore, when the fuel burns in the combustion chamber, it is easy to receive heat generated by the combustion. For this reason, in the conventional hollow valve, in order to transmit this heat in the direction of the valve stem, a hollow portion is formed inside the valve stem and the umbrella portion, and a refrigerant that becomes a liquid during operation of the internal combustion engine is enclosed in the hollow portion. There is something to do. As a result, the hollow valve reciprocates during the operation of the intake / exhaust valve device of the internal combustion engine, so that the refrigerant in the hollow part flows in the hollow part, so that the heat of the umbrella part is transmitted to the valve stem via the refrigerant.

  However, when the amount of heat generated during operation of the internal combustion engine is large, the amount of heat received by the umbrella portion of the hollow valve increases, but the amount of heat received by the umbrella portion is limited because there is a limit to the heat transfer due to the flow of the refrigerant. However, if the amount of heat transmitted to the direction of the valve stem is increased by the flow of the refrigerant, the temperature of the umbrella may be significantly increased. Thus, it becomes difficult to cool the umbrella portion of the hollow valve only by cooling by the flow of the refrigerant, and if the temperature of the umbrella portion rises too much, it may be damaged by this heat. Therefore, some conventional intake and exhaust valve devices for internal combustion engines cool the umbrella portion of the hollow valve by a method other than the flow of the refrigerant. For example, in patent document 1, the non-condensable gas in a hollow part is removed and the hollow valve is provided so that it may have a heat pipe effect. That is, when the umbrella portion is heated, the refrigerant is heated by the heat, the refrigerant evaporates, and the evaporated refrigerant returns to the liquid by radiating heat through the valve stem, and again absorbs the heat of the umbrella portion. That is, when the refrigerant recirculates, the cooling performance of the umbrella portion by the refrigerant can be dramatically improved, and the temperature of the umbrella portion is prevented from becoming too high.

JP-A-4-136406

  However, in recent internal combustion engines, the amount of heat generated is further increased due to improved performance. For this reason, when the hollow valve is formed to have a heat pipe effect and the heat of the umbrella is absorbed by the refrigerant as the refrigerant evaporates, the amount of heat taken away from the umbrella by the evaporation of the refrigerant. However, the amount of heat received by the umbrella due to the combustion of the fuel may increase. In this case, there is a possibility that the cooling of the umbrella portion by the refrigerant does not catch up with the temperature rise of the umbrella portion, and a phenomenon that the evaporated refrigerant becomes a liquid and does not return to the umbrella portion again, that is, a so-called dryout phenomenon. As described above, when the dry-out phenomenon occurs, it becomes difficult to cool the umbrella portion with the refrigerant. Therefore, the temperature of the umbrella portion continues to rise, and the umbrella portion may be damaged by this heat.

  The present invention has been made in view of the above, and an object of the present invention is to provide an intake / exhaust valve device for an internal combustion engine that can cool the hollow valve more reliably.

  In order to solve the above-described problems and achieve the object, an intake / exhaust valve device for an internal combustion engine according to the present invention has an umbrella part constituting a part of a combustion chamber at one end of a valve stem and at least the inside of the valve stem. Is an intake / exhaust valve device for an internal combustion engine, in which a hollow portion is formed, and a refrigerant is sealed in the hollow portion, and a hollow valve is provided in which the refrigerant circulates according to the operating state of the internal combustion engine. And a valve temperature detecting means for detecting the temperature of the hollow valve, and a valve cooling means for cooling the hollow valve when the temperature detected by the valve temperature detecting means is higher than a predetermined temperature.

  In this invention, the temperature of the valve stem is detected by the valve temperature detecting means, and when the temperature is higher than a predetermined temperature, the hollow valve is cooled by the valve cooling means. As a result, it is possible to prevent the refrigerant from recirculating in the hollow portion from being caught up by the temperature of the hollow valve excessively rising during operation of the internal combustion engine. That is, this hollow valve has a heat pipe effect due to the recirculation of the refrigerant. However, when the temperature of the hollow valve rises due to fuel combustion in the combustion chamber and the hollow valve operates as a heat pipe, the umbrella in the hollow portion The refrigerant located on the part side absorbs the heat of the umbrella part whose temperature has risen to cool the umbrella part, and the liquid refrigerant evaporates and changes to gas. This gaseous refrigerant dissipates heat on the valve stem side in the hollow part and returns to the liquid again, returns to the umbrella part side in the hollow part and cools the umbrella part again, but if the temperature of the hollow valve rises too much, the refrigerant becomes liquid. It is impossible to return, that is, dryout occurs. For this reason, the temperature of the valve stem is detected by the valve temperature detecting means, and when the temperature is higher than a predetermined temperature, the hollow valve is cooled by the valve cooling means, whereby the gaseous refrigerant can be returned to the liquid. . Thereby, the heat | fever on the umbrella part side of the hollow valve | bulb where the temperature rose can be absorbed more reliably and cooled with the liquid refrigerant. As a result, the hollow valve can be cooled more reliably.

  In the intake / exhaust valve device for an internal combustion engine according to the present invention, the valve cooling means includes a first cooling means and a second cooling means, and the second cooling means includes the valve stem or the At least one of the valve guides that slidably supports the valve stem is cooled, and the first cooling means has the second cooling means when at least the temperature detected by the valve temperature detecting means is higher than a predetermined temperature. It is characterized by cooling.

  In this invention, since the second cooling means cools at least one of the valve stem and the valve guide, the hollow valve can be cooled by the second cooling means. Further, when the temperature of the hollow valve detected at least by the valve temperature detecting means is higher than the predetermined temperature, the first cooling means cools the second cooling means. In this case, the cooling performance of the second cooling means is increased and the hollow cooling temperature is increased. The valve can be cooled. As a result, the hollow valve can be cooled more reliably.

  Also, in the intake / exhaust valve device for an internal combustion engine according to the present invention, the second cooling means has a second cooling means refrigerant sealed therein, and the second cooling means refrigerant is the second cooling means. It recirculate | reflux according to the temperature of this.

  In the present invention, the second cooling means refrigerant is sealed inside the second cooling means, and the second cooling means refrigerant flows back according to the temperature of the second cooling means. Has a heat pipe effect. For this reason, when the dry-out occurs in the hollow portion of the hollow valve, the dry-out can be more reliably suppressed by causing the second cooling means to operate as a heat pipe. That is, the cooling efficiency of the second cooling means is improved when dry out of the hollow valve occurs, so that the dry out of the refrigerant can be more reliably suppressed. As a result, the hollow valve can be cooled more reliably. In addition, by changing the cooling efficiency of the second cooling means in this way, when the dryout in the hollow valve is suppressed, the second cooling means is made into a heat pipe structure so that it can be easily made with a simple structure. The cooling efficiency of the second cooling means can be changed. As a result, the structure for cooling the hollow valve more reliably can be simplified.

  In the intake / exhaust valve device for an internal combustion engine according to the present invention, an ignition plug is provided in the combustion chamber, and the temperature change rate of the hollow valve is determined from the temperature of the hollow valve detected by the valve temperature detecting means. A valve temperature change rate determining means for detecting the valve temperature change rate, and the valve temperature change rate determining means retards the ignition timing of the spark plug when the temperature of the hollow valve decreases at a decrease rate equal to or higher than a predetermined decrease rate. It is characterized by doing.

  In the present invention, the temperature change rate of the hollow valve is detected, and when the temperature of the hollow valve decreases at a rate that is equal to or higher than a predetermined rate, knocking is suppressed by retarding the ignition timing of the spark plug. Yes. That is, when dryout occurs in the hollow portion of the hollow valve, the refrigerant moving in the direction from the umbrella portion toward the valve stem is reduced, so that the temperature of the valve stem is lowered. For this reason, the temperature change rate of the valve stem of the hollow valve is detected, and if the rate of decrease in the valve stem temperature is equal to or greater than the predetermined rate of decrease, it can be determined that dryout has occurred in the hollow portion. it can. Further, when dryout occurs in the hollow part, the temperature of the umbrella part of the hollow valve rises rapidly. When the temperature of the umbrella part rises in this way, there is a possibility that knocking may occur in the combustion chamber using this part as a heat spot, so if it is determined that dryout has occurred in the hollow part The knocking is suppressed by retarding the ignition timing of the spark plug. As a result, since the ignition timing can be retarded before knocking occurs, knocking can be more reliably suppressed.

  The intake / exhaust valve device for an internal combustion engine according to the present invention further comprises valve temperature change rate determination means for detecting a temperature change rate of the hollow valve from the temperature of the hollow valve detected by the valve temperature detection means, The temperature change rate determination means changes the air-fuel ratio of the fuel and the air taken into the combustion chamber in a rich direction when the temperature of the hollow valve decreases at a decrease rate equal to or higher than a predetermined decrease rate. And

  In the present invention, as described above, the temperature change rate of the hollow valve is detected, and when the temperature of the hollow valve decreases at a rate that is equal to or higher than a predetermined rate, the empty space between the fuel and air taken into the combustion chamber Knocking can be suppressed by changing the fuel ratio in the rich direction. As a result, since the air-fuel ratio can be changed in the rich direction before knocking occurs, knocking can be more reliably suppressed.

  The intake / exhaust valve device for an internal combustion engine according to the present invention further comprises valve temperature change rate determination means for detecting a temperature change rate of the hollow valve from the temperature of the hollow valve detected by the valve temperature detection means, The temperature change rate determination means is characterized in that the valve overlap period is increased when the temperature of the hollow valve decreases at a decrease rate equal to or higher than a predetermined decrease rate.

  In the present invention, similarly to the above, when the temperature change rate of the hollow valve is detected, and the temperature of the hollow valve decreases at a rate that is equal to or higher than a predetermined rate, the valve overlap period between the intake valve and the exhaust valve Is increasing. Thereby, generation | occurrence | production of the dryout in a hollow part when an exhaust valve is a hollow valve can be suppressed. In other words, when the temperature change rate of the hollow valve is detected and it is determined that dryout has occurred in the hollow part of the exhaust valve, the fresh air from the intake port is removed by increasing the valve overlap period. The exhaust valve can be cooled by this fresh air. Therefore, the exhaust valve can be cooled not only by the above-described valve cooling means but also by this fresh air, and the occurrence of dryout can be more reliably suppressed. As a result, the hollow valve can be cooled more reliably.

  The intake / exhaust valve device for an internal combustion engine according to the present invention further comprises cooling performance adjusting means for adjusting the cooling performance of the valve cooling means, and the valve is adjusted by the cooling performance adjusting means according to the operating state of the internal combustion engine. The cooling performance of the cooling means is adjusted.

  In the present invention, the cooling performance adjusting means for adjusting the cooling performance of the valve cooling means is provided. By switching the cooling performance of the valve cooling means with this cooling performance adjusting means, the cooling performance for the hollow valve by the valve cooling means is improved. Can be adjusted. Thus, by adjusting the cooling performance for the hollow valve, it is possible to prevent the hollow valve from being cooled more than necessary when the hollow valve need not be cooled much. That is, if the temperature of the umbrella portion of the hollow valve is too low, the fuel combustion efficiency is reduced, so it is better not to cool the hollow valve more than necessary. For example, in a state where the possibility of knocking is low, such as when the load is not so high, the hollow valve should be maintained at a high temperature that does not damage the umbrella due to heat. Therefore, by adjusting the cooling performance of the valve cooling means by the cooling performance adjusting means, it is possible to suppress the temperature of the hollow valve from becoming too low, and to suppress a decrease in combustion efficiency. As a result, the operating efficiency of the internal combustion engine can be improved.

  The intake / exhaust valve device for an internal combustion engine according to the present invention further comprises load detection means for detecting a load of the internal combustion engine, and the cooling performance adjusting means according to the load of the internal combustion engine detected by the load detection means. And adjusting the cooling performance of the valve cooling means.

  In this invention, the load during the operation of the internal combustion engine is detected by the load detection means, and the cooling performance of the valve cooling means is adjusted according to the detection result of the load. When the load of the internal combustion engine is other than a high load, the possibility of knocking is small, and when the hollow valve is cooled, the cooling loss increases, so when the possibility of knocking is small, the hollow valve Don't overcool. Therefore, by detecting the load of the internal combustion engine and adjusting the cooling performance of the valve cooling means with the cooling performance adjusting means when the load during operation of the internal combustion engine is other than a high load, the temperature of the hollow valve becomes too low. This can be suppressed, and a decrease in combustion efficiency due to an increase in cooling loss can be suppressed. As a result, the operating efficiency of the internal combustion engine can be improved.

  The intake / exhaust valve device for an internal combustion engine according to the present invention further comprises knock detection means for detecting knocking during combustion of fuel in the combustion chamber, and knocking in the combustion chamber is detected by the knock detection means. In this case, the hollow valve is cooled.

  In the present invention, knock detection means is provided to detect knocking during fuel combustion, and when knocking occurs, the hollow valve is cooled by the valve cooling means. Knocking is likely to occur when a heat spot is generated in the combustion chamber, and when the heat spot is generated, the temperature of the combustion chamber tends to be high overall. Therefore, by cooling the hollow valve when knocking occurs, it is possible to make it difficult to generate a heat spot, and when the umbrella portion is a heat spot, the heat spot can be more reliably removed. As a result, knocking can be more reliably suppressed.

  The intake / exhaust valve device for an internal combustion engine according to the present invention has an effect that the hollow valve can be cooled more reliably.

  Embodiments of an intake / exhaust valve device for an internal combustion engine according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. In addition, constituent elements in the following embodiments include those that can be easily replaced by those skilled in the art or those that are substantially the same.

  1 is a partial cross-sectional view of an internal combustion engine including an intake / exhaust valve device for an internal combustion engine according to Embodiment 1 of the present invention. The internal combustion engine 1 shown in the figure has a plurality of cylinders, and each cylinder has a cylinder head 5 and a cylinder block 6 in which a combustion chamber 11 is formed. A piston 10 is disposed inside the cylinder block 6, and an intake port 7 and an exhaust port 8 communicating with the combustion chamber 11 are formed in the cylinder head 5. The cylinder head 5 is fixed to the end of the cylinder block 6 on the side of the direction in which the piston 10 in the cylinder block 6 is directed to the top dead center via a gasket (not shown).

  The cylinder head 5 is provided with a spark plug 9 and an intake / exhaust valve device 20. The intake / exhaust valve device 20 includes an intake valve 26 and an exhaust valve 27, and the intake valve 26 is provided so as to communicate or block the intake port 7 and the combustion chamber 11. 27 is provided to communicate or block the exhaust port 8 and the combustion chamber 11. The spark plug 9 is provided between the intake valve 26 and the exhaust valve 27, and further has an ignition part (not shown) that discharges when a high voltage is applied. It is provided so as to be located in the combustion chamber 11.

  Each of the intake valve 26 and the exhaust valve 27 has a valve stem 28 and an umbrella portion 29. The umbrella portion 29 is formed in a shape close to a conical shape, and the bottom surface of the conical shape is formed as a valve surface 30. The valve stem 28 is located on the side opposite to the valve surface 30 side in the umbrella portion 29. The intake valve 26 and the exhaust valve 27 formed in this way are arranged in the cylinder head 5 in such a direction that the valve surface 30 is located on the combustion chamber 11 side. Part of it.

  Around the valve stem 28 of the intake valve 26 and the exhaust valve 27 formed in this way, the valve guide 23 is fixed to the cylinder head 5 and supports the valve stem 28 so as to be slidable, and contacts the valve stem 28. Is provided. The valve guide 23 is formed in a substantially cylindrical shape, and the valve stem 28 is supported by the valve guide 23 by inserting the inside of the cylindrical shape.

  A spring 22 is provided around the end of the valve stem 28 opposite to the end on the umbrella portion 29 side. Further, the spring 22 has a substantially cylindrical shape with one end closed. The lifter 21 formed in the shape is arranged. The lifter 21 is disposed so as to cover the spring 22 in such a direction that the closed portion is positioned on the opposite side of the umbrella portion in the intake valve 26 and the exhaust valve 27. Further, the spring 22 is formed so as to be able to expand and contract in the axial direction of the valve stem 28, and the respective umbrella portions 29 with respect to the intake valve 26 and the exhaust valve 27 are connected to the intake port 7 or the exhaust port 8 and the combustion chamber 11. Energizing force is given in the direction of shielding. The cam 12 is positioned around the end of the lifter 21 on the closed side. The cam 12 is positioned on both the intake valve 26 and the exhaust valve 27, and a plurality of cams 12 are formed integrally with a camshaft (not shown) on both the intake valve 26 side and the exhaust valve 27 side. . Thus, the cam 12 formed integrally with the camshaft rotates as the camshaft rotates. The lifter 21 is in contact with the outer peripheral surface portion of the cam.

  Further, the internal combustion engine 1 is provided with an oil pump 71 that sends out oil that lubricates the sliding portion and cools the high temperature portion, and is connected to the oil pump 71 to supply oil to each portion. An oil path 70 is provided, and an auxiliary cooling oil pump 60 is connected to the oil path 70. An auxiliary cooling oil pump cooling water passage 62 is provided around the auxiliary cooling oil pump 60, and an auxiliary cooling cooling water valve 61 is connected to the auxiliary cooling oil pump cooling water passage 62. Yes. An auxiliary cooling path 50 is connected to the auxiliary cooling oil pump 60, and the auxiliary cooling path 50 is connected to an auxiliary cooling oil passage 51 formed in the cylinder head 5. The auxiliary cooling oil pump 60 and the auxiliary cooling cooling water valve 61 are connected to an ECU (Electric Control Unit) 80 provided in a vehicle (not shown) on which the internal combustion engine 1 is mounted.

  The auxiliary cooling oil passages 51 provided in the cylinder head 5 are provided so as to be located over a plurality of cylinders provided. Further, an auxiliary cooling oil pipe 52 is connected to the auxiliary cooling oil passage 51, and further, of the end portions of the auxiliary cooling oil pipe 52, opposite to the end portion on the side connected to the auxiliary cooling oil passage 51. An oil jet 53 serving as a valve cooling means is provided at the end on the side. The oil jet 53 can inject oil supplied to the auxiliary cooling oil pipe 52 in the direction of the exhaust valve 27, and specifically, can inject in the direction of the valve stem 28 of the exhaust valve 27. .

  Further, a temperature sensor 40 serving as a valve temperature detecting means for detecting the temperature of the valve guide 23 is provided in the vicinity of the valve guide 23, and knocking is detected in the vicinity of the combustion chamber 11 when fuel is burned. A knock sensor 45 serving as a knock detection means is provided. These temperature sensor 40 and knock sensor 45 are connected to the ECU 80.

  FIG. 2 is a cross-sectional view of the exhaust valve shown in FIG. The exhaust valve 27 is provided as a hollow valve 25, and a hollow portion 31 that is a hollow continuously formed from the inside of the valve stem 28 to the inside of the umbrella portion 29 is formed. The inside of the hollow portion 31 is in a vacuum or a state close to a vacuum, and the refrigerant 35 is sealed in the hollow portion 31.

  FIG. 3 is an explanatory diagram of the ECU shown in FIG. The ECU 80 is provided with a storage unit 81 and a processing unit 82. The storage unit 81 stores a computer program for controlling the intake / exhaust valve device 20 of the internal combustion engine 1 according to the present invention. The storage unit 81 is a hard disk device, a magneto-optical disk device, a non-volatile memory such as a flash memory (a storage medium that can be read only such as a CD-ROM), or a RAM (Random Access Memory). A volatile memory or a combination thereof can be used. Further, the ECU 80 is provided with an input circuit 85 and an output circuit 86, the temperature sensor 40 and the knock sensor 45 are connected to the input circuit 85, and the auxiliary cooling oil pump 60 and the auxiliary cooling cooling water valve 61 are output. The circuit 86 is connected. The input circuit 85 and the output circuit 86 are connected to the storage unit 81 and the processing unit 82.

  The processing unit 82 includes a memory 83 and a CPU (Central Processing Unit) 84. The amount of oil injected from the oil jet 53 to the valve stem 28 of the exhaust valve 27 during operation of the internal combustion engine 1 is determined by the processing unit 82 based on the detection results detected by the temperature sensor 40 and the knock sensor 45. Is read into the memory 83 incorporated in the processing unit 82 and calculated. At that time, the processing unit 82 appropriately stores a numerical value in the middle of the calculation in the storage unit 81, and takes out the stored numerical value and executes the calculation. When the intake / exhaust valve device 20 of the internal combustion engine 1 is controlled in this way, it may be controlled by dedicated hardware different from the ECU 80 instead of the computer program.

  The intake / exhaust valve device 20 of the internal combustion engine 1 according to the first embodiment is configured as described above, and the operation thereof will be described below. The internal combustion engine 1 is operated by repeatedly performing an intake stroke, a compression stroke, a combustion stroke, and an exhaust stroke by repeating the reciprocating motion of the piston 10 in the cylinder block 6. The outline of each stroke is as follows. In the intake stroke, the exhaust valve 27 is closed, the intake valve 26 is opened, and a mixture of fuel and air is taken into the combustion chamber 11 from the intake port 7, and in the compression stroke, the intake valve 26 is also closed. The air-fuel mixture taken into the combustion chamber 11 is compressed. In the combustion stroke, a high-voltage current is applied to the spark plug 9 and discharge is generated in the ignition part of the spark plug 9, thereby igniting the compressed air-fuel mixture and burning the fuel in the air-fuel mixture. In the exhaust stroke, the exhaust valve 27 is opened, and the exhaust gas after combustion is discharged in the direction of the exhaust port 8.

  Further, the operation of the intake valve 26 and the exhaust valve 27 is performed by the intake valve 26 and the exhaust valve 27 to which a biasing force is applied in a direction to shield the intake port 7 or the exhaust port 8 and the combustion chamber 11 by the spring 22. This is done by being pushed by the cam 12 and communicating the intake port 7 or the exhaust port 8 with the combustion chamber 11. That is, both valves are biased in the direction of the cam 12 by the spring 22, but the camshaft formed integrally with the cam 12 rotates to contact the outer peripheral surface of the cam 12. The lifter 21 is moved following the shape of the cam 12, and the intake valve 26 and the exhaust valve 27 reciprocate together with the lifter 21. Thereby, the intake port 7 and the exhaust port 8 are opened and closed.

  Further, in the combustion chamber 11, fuel burns during the combustion stroke. Therefore, the temperature of the valve surfaces 30 of the intake valve 26 and the exhaust valve 27 facing the flame at the time of combustion rises due to the flame, and the umbrella portion 29 as a whole. Temperature rises. In particular, since the exhaust valve 27 is positioned on the exhaust port 8 side through which the high-temperature exhaust gas after combustion passes, the exhaust valve 27 becomes higher in temperature than the intake valve 26. The heat of the umbrella portion 29 of the exhaust valve 27 that has become high in this way is transmitted to the refrigerant 35 enclosed in the hollow portion 31 inside. The refrigerant 35 is in a liquid state at the temperature of the exhaust valve 27 when the load during operation of the internal combustion engine 1 is relatively low. When the internal combustion engine 1 is in operation, the exhaust valve 27 reciprocates as described above. Therefore, the refrigerant 35 also moves in the hollow portion 31 by this reciprocation. As described above, when the refrigerant 35 moves in the hollow portion 31, the heat received by the umbrella 35 at the umbrella portion 29 is transmitted to the valve stem 28 when the refrigerant 35 moves in the direction of the valve stem 28. Further, the heat transmitted to the valve stem 28 is transmitted to the valve guide 23 in contact with the valve stem 28, and the heat of the exhaust valve 27 is radiated to the valve guide 23.

  When the load during the operation of the internal combustion engine 1 is relatively small, the refrigerant 35 in the hollow portion 31 of the exhaust valve 27 is liquid as described above, but the load during the operation of the internal combustion engine 1 is increased and the fuel is increased. When the heat received by the exhaust valve 27 due to combustion increases and the temperature of the umbrella portion 29 of the exhaust valve 27 further increases, the temperature of the refrigerant 35 also rises, and the refrigerant 35 evaporates into a gas. Thus, when the liquid refrigerant 35 absorbs heat and becomes a gas, the refrigerant 35 absorbs more heat than the liquid 35 absorbs heat while being liquid. For this reason, the heat of the umbrella part 29 which became high temperature is absorbed with the refrigerant | coolant 35, and the temperature of the umbrella part 29 falls.

  On the other hand, the refrigerant 35 that has become gas moves toward the valve stem 28 of the exhaust valve 27. Since the valve stem 28 is in contact with the valve guide 23, the heat received from the refrigerant 35 can be dissipated to the valve guide 23 as described above, and the temperature is not likely to be too high. For this reason, the gaseous refrigerant 35 moved in the direction of the valve stem 28 radiates heat to the valve stem 28. That is, the heat of the refrigerant 35 is radiated to the valve guide 23 through the valve stem 28. As described above, when the heat of the gaseous refrigerant 35 dissipates heat to the valve stem 28, the refrigerant 35 returns to a liquid. The refrigerant 35 that has returned to the liquid moves again in the direction of the umbrella part 29, absorbs the heat of the umbrella part 29, evaporates into a gas, and moves in the direction of the valve stem 28. By repeating these steps, the refrigerant 35 recirculates, so that the temperature of the umbrella 29 that has become higher due to the combustion of the fuel decreases. That is, when the temperature of the exhaust valve 27 becomes equal to or higher than a predetermined temperature, the refrigerant 35 recirculates, so that the exhaust valve 27 operates as a heat pipe, and the heat transfer rate from the umbrella portion 29 toward the valve stem 28 is improved. For this reason, when the temperature of the exhaust valve 27 becomes equal to or higher than a predetermined temperature, the temperature of the umbrella portion 29 decreases due to the heat pipe effect of the exhaust valve 27.

  When the load during operation of the internal combustion engine 1 is further increased, the heat received by the exhaust valve 27 further increases. When the heat received by the exhaust valve 27 increases, the amount of the refrigerant 35 that absorbs the heat of the umbrella 29 and moves in the direction of the valve stem 28 as a gas increases. When the amount of the refrigerant 35 that moves in the direction of the valve stem 28 increases in this way, the amount of heat that the refrigerant 35 radiates to the valve stem 28 increases more than the amount of heat that the valve stem 28 radiates through the valve guide 23. . For this reason, the temperature of both the valve stem 28 and the valve guide 23 becomes high. Here, a temperature sensor 40 is provided in the vicinity of the valve guide 23, and the temperature of the valve guide 23 is detected by the temperature sensor 40. The temperature sensor 40 is connected to the ECU 80, and the detected temperature of the valve guide 23 is transmitted to the ECU 80. The temperature sensor 40 is thus provided in the vicinity of the valve guide 23 and measures the temperature of the valve guide 23. The valve guide 23 indirectly detects the temperature of the exhaust valve 27. That is, since the valve guide 23 is in contact with the valve stem 28 of the exhaust valve 27, the valve guide 23 changes according to the temperature change of the valve stem 28. Accordingly, the temperature sensor 40 indirectly detects the temperature of the valve stem 28 of the exhaust valve 27 via the valve guide 23.

  Therefore, the ECU 80 determines that the temperature of the valve stem 28 or the exhaust valve 27 is equal to or higher than the heat pipe operating range when the temperature detected by the temperature sensor 40 is equal to or higher than a predetermined temperature. Auxiliary cooling is performed. When performing auxiliary cooling, the ECU 80 operates the auxiliary cooling oil pump 60. When the auxiliary cooling oil pump 60 is operated, a part of the oil flowing through the oil passage 70 is supplied to the auxiliary cooling oil passage 51 through the auxiliary cooling passage 50. The ECU 80 opens the auxiliary cooling coolant valve 61 simultaneously with the operation of the auxiliary cooling oil pump 60. When the auxiliary cooling cooling water valve 61 is opened, the cooling water for cooling the internal combustion engine 1 during operation flows through the auxiliary cooling oil pump cooling water passage 62 provided around the auxiliary cooling oil pump 60 to cool it. Oil flowing through the auxiliary cooling oil pump 60 is cooled by heat exchange with water. For this reason, the oil supplied to the auxiliary cooling oil passage 51 through the auxiliary cooling path 50 is supplied with the oil cooled by the cooling water. Further, the oil supplied to the auxiliary cooling oil passage 51 passes through the auxiliary cooling oil pipe 52 and is injected in the direction of the valve stem 28 from the oil jet 53 provided at the tip thereof.

  The oil jetted from the oil jet 53 is cooled by the cooling water, and the temperature of the valve stem 28 is lowered by jetting the oil onto the valve stem 28. Thereby, the exhaust valve 27 is subjected to auxiliary cooling. When the temperature of the valve stem 28 decreases, the refrigerant 35 that is in the gas in the hollow portion 31 of the exhaust valve 27 can radiate heat to the valve stem 28, so that it returns to liquid again and moves toward the umbrella portion 29. That is, when the oil is injected from the oil jet 53, the exhaust valve 27 returns to the temperature within the heat pipe operating range, and the temperature of the umbrella portion 29 is lowered by the heat pipe effect.

FIG. 4 is a diagram showing the amount of heat transport with respect to the load of the internal combustion engine. FIG. 5 is a diagram showing the valve temperature with respect to the load of the internal combustion engine. Thus, as the load during operation of the internal combustion engine 1 increases, the amount of heat received by the umbrella portion 29 of the exhaust valve 27 from the flame during combustion of the fuel increases, and the temperature of the exhaust valve 27 rises. When the temperature of the exhaust valve 27 is lower than the temperature at which the exhaust valve 27 operates as a heat pipe, that is, the temperature T ₁ detected by the temperature sensor 40 is the lower limit temperature of the temperature at which the exhaust valve 27 operates as a heat pipe. When the temperature is lower than the heat pipe operation lower limit temperature T ₂ , the refrigerant 35 in the hollow portion 31 transfers heat from the umbrella portion 29 to the valve stem 28 while remaining in a liquid state. Further, the temperature of the exhaust valve 27 increases, and the temperature T ₁ detected by the temperature sensor 40 is the heat pipe operation lower limit temperature T ₂ and the upper limit temperature of the temperature at which the exhaust valve 27 operates as a heat pipe. In the case of the temperature T ₃ , the amount of heat transferred from the umbrella portion 29 to the valve stem 28 increases due to the heat pipe effect. Further, when the temperature T ₁ detected by the temperature sensor 40 is higher than the heat pipe operation upper limit temperature T ₃ , oil is injected from the oil jet 53 to the valve stem 28 to assist cooling of the valve stem 28. The temperature of the exhaust valve 27 maintains a temperature between the heat pipe operation upper limit temperature T ₃ and the heat pipe operation lower limit temperature T ₂ . Thereby, since the exhaust pipe 27 maintains the heat pipe effect, even when the umbrella portion 29 of the exhaust valve 27 receives a large amount of heat, the amount of heat transported from the umbrella portion 29 toward the valve stem 28 increases.

Thus, when the temperature of the valve stem 28 becomes high, the amount of heat transported in the direction from the umbrella portion 29 to the valve stem 28 when the oil jet 53 injects oil into the valve stem 28 and performs auxiliary cooling. The heat quantity 91 during auxiliary cooling continues to increase as the load during operation of the internal combustion engine 1 increases (FIG. 4). Further, by carrying out the auxiliary cooling in this way, even when the load of the internal combustion engine 1 becomes high, the amount of transport heat continues to increase. Therefore, the valve temperature 95 during auxiliary cooling, which is the temperature of the valve stem 28 at that time, It is maintained between the pipe operation upper limit temperature T ₃ and the heat pipe operation lower limit temperature T ₂ (FIG. 5).

On the other hand, when the auxiliary cooling of the exhaust valve 27 is not performed, when the temperature of the valve stem 28 becomes equal to or higher than the heat pipe operation upper limit temperature T ₃ , the refrigerant 35 that has become a gas does not return to the liquid. Will occur. When dryout occurs, the amount of heat transferred from the umbrella 29 to the valve stem 28 by the refrigerant 35 is drastically reduced. Therefore, the non-auxiliary cooling transport heat quantity 92, which is the transport heat quantity in the direction from the umbrella 29 to the valve stem 28 when the auxiliary cooling is not performed, is high while the load during the operation of the internal combustion engine 1 is low. It continues to increase as the load increases, but the load further increases and drastically decreases when dryout occurs (FIG. 4). Further, when the auxiliary cooling of the exhaust valve 27 is not performed as described above, the amount of transport heat is drastically reduced when the load of the internal combustion engine 1 is increased. Therefore, the non-auxiliary cooling which is the temperature of the valve stem 28 at that time. The hour valve temperature 96 increases as the load on the internal combustion engine 1 increases and the umbrella 29 receives a lot of heat (FIG. 5).

The intake / exhaust valve device 20 of the internal combustion engine 1 detects the temperature of the valve guide 23 with the temperature sensor 40, indirectly detects the temperature of the valve stem 28 of the exhaust valve 27, and detects the detected temperature T of the valve stem 28. _{When 1} is higher than the heat pipe operation upper limit temperature T ₃ , the ECU 80 operates the auxiliary cooling oil pump 60 to inject oil from the oil jet 53 to the valve stem 28. As a result, the valve stem 28 is auxiliary cooled and the temperature decreases, so that the occurrence of dryout of the refrigerant 35 enclosed in the hollow portion 31 due to the temperature of the exhaust valve 27 becoming too high is suppressed. Can do. As a result, the exhaust valve 27 that is the hollow valve 25 can be cooled more reliably.

  Further, since the exhaust valve 27 has a heat pipe effect, even when the valve surface 30 of the exhaust valve 27 receives a large amount of heat due to the combustion of fuel, the exhaust valve 27 is transported from the umbrella portion 29 toward the valve stem 28 by the refrigerant 35. Since the amount of heat increases, damage to the exhaust valve 27 caused by the exhaust valve 27 becoming too hot can be suppressed. As a result, the durability of the exhaust valve 27 can be improved.

  Further, since the exhaust valve 27 has a heat pipe effect, the load during operation of the internal combustion engine 1 increases, and even if the amount of heat transmitted to the exhaust valve 27 increases, the exhaust valve 27 is not easily damaged. The engine 1 can be operated with a large load. As a result, the performance of the internal combustion engine 1 can be improved.

  Further, an auxiliary cooling oil pump cooling water passage 62 is provided around the auxiliary cooling oil pump 60. When the auxiliary cooling oil pump 60 is operated, the auxiliary cooling cooling water valve 61 is opened, and the auxiliary cooling oil pump 61 is opened. The oil sent out to the auxiliary cooling path 50 by the pump 60 is cooled. Thereby, since the temperature of the oil injected toward the valve stem 28 by the oil jet 53 can be lowered, the temperature of the valve stem 28 that has become high temperature can be lowered more reliably. As a result, the occurrence of dryout can be suppressed more reliably, and the exhaust valve 27 can be cooled more reliably.

  The intake / exhaust valve device for the internal combustion engine has substantially the same configuration as the intake / exhaust valve device for the internal combustion engine according to the first embodiment, but is characterized in that a valve guide cooling unit is provided in the valve guide. Since other configurations are the same as those of the first embodiment, the description thereof is omitted and the same reference numerals are given. FIG. 6 is a detailed view of a main part of an intake / exhaust valve device for an internal combustion engine according to a second embodiment of the present invention. The valve guide 100 of the intake / exhaust valve device 20 of the internal combustion engine 1 shown in the figure is provided with a valve guide cooling unit 101 serving as a second cooling means. The valve guide cooling unit 101 has a hollow structure with both ends of a substantially cylindrical shape closed, and the inside is in a vacuum or a state close to a vacuum. Further, inside the valve guide cooling part 101, a valve guide cooling part refrigerant (not shown) serving as a refrigerant for the second cooling means is enclosed. The refrigerant for the valve guide cooling section changes from a liquid to a gas at a temperature similar to or slightly lower than that of the refrigerant 35 enclosed in the exhaust valve 27. For this reason, the valve guide cooling unit 101 has a heat pipe effect in a temperature range similar to or slightly lower than that of the exhaust valve 27. The valve guide cooling unit 101 is screwed to the valve guide 100 in such a form having a heat pipe effect.

  In addition, a radiating fin 102 is provided at the end of the valve guide cooling unit 101 opposite to the end of the valve guide cooling unit 101 that is screwed to the valve guide 100. The heat radiating fins 102 are formed by fixing a plurality of thin plates at intervals to a cylindrical outer peripheral surface that is the shape of the valve guide cooling unit 101. Further, the oil jet 53 is provided as a first cooling means, and is arranged in a direction in which oil can be injected in the direction of the radiation fins 102.

  The intake / exhaust valve device 20 of the internal combustion engine 1 according to the second embodiment is configured as described above, and the operation thereof will be described below. In the intake / exhaust valve device 20 of the internal combustion engine 1 according to the second embodiment, during operation of the internal combustion engine 1, oil is always injected from the oil jet 53 toward the valve guide cooling unit 101, and the valve guide cooling unit 101 is auxiliary cooled. . When the internal combustion engine 1 is operated in this state, when the load is low, the temperature of the exhaust valve 27 does not increase so much, and therefore the temperature of the valve guide cooling unit 101 provided in the valve guide 100 does not increase too much. For this reason, the valve guide cooling part refrigerant in the valve guide cooling part 101 maintains a liquid state, and the heat transfer rate from the valve guide 100 side to the heat radiation fin 102 side in the valve guide cooling part 101 becomes low. The cooling efficiency of the guide cooling unit 101 is lowered.

  When the load during operation of the internal combustion engine 1 increases, the temperature of the valve stem 28 of the exhaust valve 27 increases, and the temperature of the valve guide 100 also increases accordingly. When the temperature of the valve guide 100 rises, the refrigerant in the valve guide cooling unit 101 absorbs the heat of the valve guide 100 to become a gas, and moves from the valve guide 100 side to the radiation fin 102 side in the valve guide cooling unit 101. . Since oil is blown to the heat radiating fins 102 by the oil jet 53, the heat of the heat radiating fins 102 is absorbed by the oil, and the heat of the refrigerant for the valve guide cooling part that has moved to the side of the heat radiating fins 102 is also absorbed. As described above, heat is removed from the valve guide cooling section refrigerant, so that the valve guide cooling section refrigerant changes from gas to liquid, and the valve guide cooling section refrigerant that has become liquid again in the valve guide cooling section 101. Move to the valve guide 100 side.

  Thus, the refrigerant for the valve guide cooling section recirculates, and the amount of heat absorbed from the valve guide 100 can be increased by repeating these actions. That is, the valve guide cooling unit 101 increases the amount of heat absorbed from the valve guide 100 by the heat pipe effect due to the recirculation of the valve guide cooling unit refrigerant. As described above, when the temperature of the valve stem 28 of the exhaust valve 27 becomes high and the temperature of the valve guide 100 becomes high, the valve guide cooling unit 101 operates as a heat pipe. The heat transfer rate from the guide 100 side to the radiating fin 102 side is improved, and much heat of the valve stem 28 is radiated to the valve guide cooling unit 101. For this reason, the cooling efficiency of the valve guide cooling unit 101 is improved. In other words, the refrigerant for the valve guide cooling unit recirculates according to the temperature of the valve guide cooling unit 101, and when the temperature of the valve guide cooling unit 101 increases, the refrigerant for the valve guide cooling unit recirculates. The cooling efficiency is improved.

  In the intake and exhaust valve device 20 of the internal combustion engine 1 described above, the valve guide 100 is provided with the valve guide cooling unit 101 whose cooling efficiency varies depending on the temperature. For this reason, when the load during operation of the internal combustion engine 1 increases, the temperature of the valve stem 28 rises to a temperature at which dryout occurs, and the temperature of the valve guide cooling unit 101 rises accordingly. In this case, the cooling efficiency of the valve guide cooling unit 101 is improved by the circulation of the refrigerant for the valve guide cooling unit. As a result, the amount of heat radiated by the valve guide cooling unit 101 via the valve guide 100 among the heat of the valve stem 28 that has increased due to an increase in the load during operation of the internal combustion engine 1 increases. Therefore, even when the temperature of the valve stem 28 rises, the cooling efficiency of the valve guide cooling unit 101 provided in the valve guide 100 is improved, so that the heat of the valve stem 28 is radiated by the valve guide cooling unit 101 and the exhaust valve 27. The occurrence of dry-out inside can be more reliably suppressed. As a result, the exhaust valve 27 that is the hollow valve 25 can be cooled more reliably.

  Further, the cooling efficiency of the valve guide cooling unit 101 can be easily changed by forming the valve guide cooling unit 101 to have a heat pipe effect. Accordingly, when the temperature of the valve stem 28 of the exhaust valve 27 is low, the cooling efficiency is lowered by preventing the valve guide cooling unit 101 from operating as a heat pipe, and when the temperature of the valve stem 28 of the exhaust valve 27 is high. Since the valve guide cooling unit 101 operates as a heat pipe to improve the cooling efficiency, more heat can be radiated by the valve guide cooling unit 101 when the temperature of the valve stem 28 rises. . Therefore, the structure of the valve guide cooling unit 101 whose cooling efficiency varies depending on the temperature can be simplified. As a result, the structure for cooling the exhaust valve 27 more reliably can be simplified.

FIG. 7 is a diagram illustrating a valve temperature with respect to a load of the internal combustion engine including the intake / exhaust valve device for the internal combustion engine according to a modification of the first embodiment. FIG. 8 is a diagram illustrating a heat transport amount with respect to a load of the internal combustion engine including the intake / exhaust valve device for the internal combustion engine according to a modification of the first embodiment. In the intake / exhaust valve device 20 of the internal combustion engine 1 of the first embodiment, when the temperature T ₁ of the valve guide 23 detected by the temperature sensor 40 is higher than the heat pipe operation upper limit temperature T ₃ , the oil jet 53 Although auxiliary cooling is performed by injecting oil into the valve stem 28, there may be a case where auxiliary cooling is not performed even in such a case. For example, when the load during operation of the internal combustion engine 1 is a medium load to a high load, a lot of heat is generated by the combustion of the fuel, and the exhaust valve 27 is dry-out within the exhaust valve 27. Although heat is transmitted, on the other hand, when the load during operation of the internal combustion engine 1 is a medium load, knocking is less likely to occur. Further, if the temperature of the portion of the exhaust valve 27 facing the space where the fuel burns, such as the valve surface 30, is too low, the cooling loss may become too large. For this reason, in a state where the load during operation of the internal combustion engine 1 is medium and knocking does not occur, the temperature T ₁ of the valve guide 23 detected by the temperature sensor 40 is higher than the heat pipe operation upper limit temperature T _3. Even in such a case, dryout may be generated in the exhaust valve 27 without auxiliary cooling.

  Specifically, the computer 80 stored in the storage unit 81 in the ECU 80 causes the ECU 80 to adjust the cooling performance adjusting means for adjusting the cooling performance of the oil jet 53 and the load detecting means for detecting the load of the internal combustion engine 1. Give function. Thus, the ECU 80 can detect the load of the internal combustion engine 1 through various sensors such as a throttle sensor (not shown) that detects a throttle opening provided in the internal combustion engine 1 during operation of the internal combustion engine 1. Further, since knock sensor 45 is connected to ECU 80, occurrence of knocking can be detected.

Therefore, when the internal combustion engine 1 is operated, the ECU 80 determines that the load during the operation of the internal combustion engine 1 is a medium load, and if no knocking is detected, the ECU 80 adjusts the cooling performance of the auxiliary cooling by the oil jet 53. To do. The adjustment method is performed by switching between operation (ON) and non-operation (OFF) of the oil jet 53. That is, the injection of oil from the oil jet 53 and the stop of the injection are switched. If the injection of oil is stopped while the temperature of the exhaust valve 27 is rising, the valve temperature 112 (FIG. 7) at the time of auxiliary cooling adjustment, which is the temperature of the exhaust valve 27 at the time of adjustment of auxiliary cooling, rises, and the heat pipe beyond the operating upper limit temperature T ₃ dryout occurs in the exhaust valve 27. In this state, when to inject oil from the oil jet 53, the auxiliary cooling during adjustment valve temperature 112 is lowered, is the following heat pipe operating upper limit temperature T _3, the temperature of the exhaust valve 27 is in the operating range of the heat pipe Become temperature. As described above, when auxiliary cooling is repeatedly turned on and off, that is, when auxiliary cooling is intermittently performed, the auxiliary cooling adjustment valve temperature 112 rises and falls across the heat pipe operation upper limit temperature T ₃ , and auxiliary cooling is performed. The valve temperature 112 at the time of auxiliary cooling adjustment rises and falls according to the auxiliary cooling state line 111 which is a line indicating the ON and OFF states (FIG. 7).

Further, by adjusting the cooling performance of the auxiliary cooling when the load during the operation of the internal combustion engine 1 is a medium load and knocking does not occur in this way, the umbrella stem 29 of the exhaust valve 27 in this case is adjusted to the valve stem 28. The amount of transport heat 121 during auxiliary cooling adjustment, which is the amount of transport heat in the direction of, does not increase when the load during operation of the internal combustion engine 1 is medium load (FIG. 8). On the other hand, if the auxiliary cooling performance is not adjusted even when the load during operation of the internal combustion engine 1 is medium and knocking does not occur, that is, when oil is continuously injected from the oil jet 53 to the valve stem 28, The auxiliary cooling non-adjustment valve temperature 113, which is the temperature of the exhaust valve 27, continues to maintain the temperature between the heat pipe operation lower limit temperature T ₂ and the heat pipe operation upper limit temperature T ₃ (FIG. 7). For this reason, since the exhaust valve 27 continues to maintain the heat pipe effect, the transport heat amount 122 at the time of auxiliary cooling non-adjustment, which is the transport heat amount from the umbrella portion 29 of the exhaust valve 27 to the valve stem 28 in this case, is an internal combustion engine. When the load during one operation is a medium load and the temperature of the exhaust valve 27 is within the operating range of the heat pipe, it becomes high (FIG. 8).

  Therefore, when the load during operation of the internal combustion engine 1 is a medium load and knocking has not occurred, the auxiliary cooling performance is not adjusted by adjusting the auxiliary cooling operation and adjusting the auxiliary cooling performance. Compared to the case, the amount of heat transported from the umbrella portion 29 of the exhaust valve 27 toward the valve stem 28 is reduced, so that the temperature of the valve surface 30 is suppressed from becoming too low. Thereby, since the exhaust valve 27 is not cooled more than necessary, the cooling loss can be reduced and the reduction in combustion efficiency can be suppressed. As a result, the operation efficiency of the internal combustion engine 1 can be improved.

  Further, when the occurrence of knocking is suppressed by detecting the load during operation of the internal combustion engine as described above, the adjustment of the performance of auxiliary cooling is not performed only by the load during operation of the internal combustion engine 1 or the presence or absence of knocking. Alternatively, this may be performed based on the temperature detected by the temperature sensor 40. That is, the temperature of the exhaust valve 27 does not change instantaneously according to the change of the load during the operation of the internal combustion engine 1, but changes depending on the overall load in a certain time. For this reason, for example, when the load is temporarily high but the temperature of the valve stem 28 has not increased so much, the possibility of knocking is low. Reduce. In addition, if the valve stem 28 is kept at a high temperature after a long period of high load, the valve stem 28 may be knocked. The knocking is suppressed by lowering the temperature of the exhaust valve 27. As a result, the suppression of knocking and the improvement of the operating efficiency of the internal combustion engine can be achieved more reliably.

  The cooling performance of the auxiliary cooling is adjusted not by intermittently injecting oil from the oil jet 53, but by adjusting the amount of oil injected from the oil jet 53, or by setting the auxiliary cooling cooling water valve 61. The temperature of the oil jetted from the oil jet 53 may be adjusted by adjusting the amount of cooling water flowing through the cooling water passage 62 for the auxiliary cooling oil pump. Also by these means, the exhaust valve 27 can be prevented from being cooled more than necessary, and a cooling loss can be reduced to suppress a reduction in combustion efficiency. As a result, the operation efficiency of the internal combustion engine 1 can be improved.

  Further, in the intake / exhaust valve device 20 of the internal combustion engine 1 according to the first embodiment, in order to detect the temperature of the valve stem 28, a temperature sensor 40 is provided in the vicinity of the valve guide 23 to detect the temperature of the valve guide 23. Thus, the temperature of the valve stem 28 in contact with the valve guide 23 is indirectly detected, but the temperature of the valve stem 28 may be directly detected. Further, the temperature of the valve stem 28 may be predicted by detecting the operation state of the internal combustion engine 1 with various sensors provided in the internal combustion engine 1. The auxiliary cooling of the valve stem 28 is performed by the oil jet 53 injecting oil into the valve stem 28. However, the auxiliary cooling may be performed by other methods. For example, an oil gallery may be provided in the valve guide 23 and the cooled oil may be circulated in this portion to perform auxiliary cooling of the valve stem 28.

  Further, in the intake / exhaust valve device 20 of the internal combustion engine 1 according to the first embodiment, only auxiliary cooling is performed when dryout occurs in the exhaust valve 27, but a countermeasure against knocking may be taken. For example, according to a computer program stored in the storage unit 81 in the ECU 80, the ECU 80 causes the ECU 80 to detect the temperature change rate of the valve stem 28 from the temperature of the valve stem 28 of the exhaust valve 27 detected by the temperature sensor 40. Provide a function of rate judging means. Thereby, the ECU 80 can detect the temperature change rate of the valve stem 28. When the temperature of the exhaust valve 27 rises and dryout occurs in the exhaust valve 27, the amount of heat transported from the umbrella portion 29 toward the valve stem 28 is drastically reduced (see FIG. 4). For this reason, since the temperature of the valve stem 28 decreases, the ECU 80 having the function of the valve temperature change rate determination means determines that the temperature of the valve stem 28 of the exhaust valve 27 has decreased at a reduction rate equal to or higher than a predetermined reduction rate. In this case, the ignition timing of the spark plug 9 is retarded as a countermeasure against knocking.

  That is, when the temperature of the valve stem 28 detected by the temperature sensor 40 continues to decrease, it is predicted that dryout has occurred in the exhaust valve 27. When dry-out occurs in the exhaust valve 27, the umbrella portion 29 of the exhaust valve 27 may suddenly become high temperature. In this case, there is a possibility that knocking may occur using the umbrella portion 29 of the exhaust valve 27 as a heat spot. For this reason, it is possible to detect the dry-out of the exhaust valve 27 at an early stage by determining the occurrence of the dry-out based on the rate of decrease in the temperature of the valve stem 28, and the temperature of the valve stem 28 is decreased beyond a predetermined decrease rate By retarding the ignition timing of the spark plug 9 when it is determined that the ratio has decreased, the occurrence of knocking in which the umbrella portion 29 becomes a heat spot can be suppressed. As a result, since the ignition timing can be retarded before knocking occurs, knocking can be more reliably suppressed.

  The occurrence of dryout in the exhaust valve 27 may be determined based on the balance between the temperature of the valve stem 28 and the load during the operation of the internal combustion engine 1, rather than the rate of decrease in the temperature of the valve stem 28. . For example, if the temperature of the valve stem 28 suddenly decreases during the continuous high-load operation, there is a possibility that a dryout has occurred in the exhaust valve 27. The ignition timing may be retarded as described above.

  In order to suppress the occurrence of knocking, a method other than retarding the ignition timing may be used. For example, the air-fuel ratio between the fuel taken into the combustion chamber 11 and air may be changed in the rich direction. By determining the occurrence of knocking based on the temperature of the valve stem 28 and changing the air-fuel ratio, the air-fuel ratio can be changed in the rich direction before knocking occurs, so that knocking can be more reliably suppressed.

  Further, when it is determined that the dry-out has occurred in the exhaust valve 27 based on the rate of decrease in the temperature of the valve stem 28, the overlap period between the intake valve 26 and the exhaust valve 27 may be increased. Thus, fresh air from the intake port 7 can easily flow to the exhaust port 8 side, and the exhaust valve 27 can be cooled by this fresh air. Therefore, the exhaust valve 27 can be cooled not only by the auxiliary cooling by the oil jet 53 but also by fresh air from the intake port 7, and the occurrence of dryout in the exhaust valve 27 can be more reliably suppressed. As a result, the exhaust valve 27 can be cooled more reliably.

  When knocking is detected by the knock sensor 45, the exhaust valve 27 may be cooled by auxiliary cooling regardless of the temperature detected by the temperature sensor 40. Knocking is likely to occur when a heat spot is generated in the combustion chamber 11, and when the heat spot is generated, the temperature of the combustion chamber 11 tends to be high as a whole. Therefore, when the knocking occurs, the exhaust valve 27 is cooled to make it difficult to generate a heat spot. When the umbrella portion 29 is a heat spot, the heat spot is more reliably removed. it can. As a result, knocking can be more reliably suppressed.

  Moreover, in the intake / exhaust valve device 20 of the internal combustion engine 1 described above, only the exhaust valve 27 becomes the hollow valve 25 and has a heat pipe effect, but the intake valve 26 also becomes the hollow valve 25 and has the heat pipe effect. You may have. When the load during operation of the internal combustion engine 1 becomes high, the intake valve 26 may also become hot and cause knocking or the like, so that the above-described control is performed with the intake valve 26 as the hollow valve 25. As a result, the intake valve 26 can be cooled more reliably. As a result, the hollow valve 25 can be cooled more reliably.

FIG. 9 is a control flowchart of the intake / exhaust valve device for the internal combustion engine according to the present invention. In addition, you may incorporate each function mentioned above in the intake / exhaust valve apparatus 20 of the internal combustion engine 1 which concerns on this invention. In this case, first, the valve stem temperature T ₁ is detected by the temperature sensor 40 via the valve guide 23 (step ST1). Next, it is determined whether the detected valve stem temperature T ₁ is within the heat pipe operating range (heat pipe operating lower limit temperature T ₂ to heat pipe operating upper limit temperature T ₃ ) (step ST2). If the valve stem temperature T ₁ is a temperature within the heat pipe operating range, then knocking is detected by the knock sensor 45 to determine whether knocking has occurred (step ST3). If knocking has occurred, the oil jet 53 continues to inject oil into the valve stem 28, that is, auxiliary cooling is always performed (step ST4). If it is determined in step ST3 that knocking has not occurred, auxiliary cooling is intermittently performed (step ST5).

  Next, it is determined from the rate of decrease in the temperature of the valve stem 28 whether dryout has occurred (step ST6). If it is determined by this determination that no dryout has occurred, this control flow ends and the process returns to step ST1 again. If it is predicted from the temperature decrease rate of the valve stem 28 that dryout is occurring, the auxiliary cooling is always performed, and further measures to prevent knocking such as reducing the load and retarding the ignition timing are taken. Perform (step ST8).

Further, the determination in the step ST2, the words, the valve stem temperatures T ₁ detected is, when it is determined whether the the heat pipe working range, the valve stem temperature T ₁ is not a temperature within the heat pipe operating range If it is determined, it is determined whether (T ₁ <T ₂ ) or (T ₁ > T ₃ ) is satisfied (step ST7). If it is determined by this determination that (T ₁ > T ₃ ), the process proceeds to the above-described step ST8, that is, the auxiliary cooling is always performed, the load is reduced, and the ignition timing is retarded. Knock prevention measures are taken (step ST8). If it is determined in step ST7 that (T ₁ <T ₂ ), auxiliary cooling is stopped (step ST9), the control flow ends, and the process returns to step ST1 again. By controlling the intake / exhaust valve device 20 of the internal combustion engine 1 according to the present invention with this control flow, the dry-out of the hollow valve 25 such as the exhaust valve 27 can be effectively suppressed, so that the cooling of the hollow valve 25 can be performed more reliably. In addition, more reliable knocking can be suppressed.

  As described above, the intake / exhaust valve device for an internal combustion engine according to the present invention is useful for an internal combustion engine having a hollow valve, and is particularly suitable for an internal combustion engine having a high load during operation.

1 is a partial cross-sectional view of an internal combustion engine including an intake / exhaust valve device for an internal combustion engine according to Embodiment 1 of the present invention. It is sectional drawing of the exhaust valve shown in FIG. It is explanatory drawing of ECU shown in FIG. It is a figure which shows the amount of heat transport with respect to the load of an internal combustion engine. It is a figure which shows the valve temperature with respect to the load of an internal combustion engine. It is principal part detail drawing of the intake / exhaust valve apparatus of the internal combustion engine which concerns on Example 2 of this invention. It is a figure which shows the valve temperature with respect to the load of an internal combustion engine provided with the intake / exhaust valve apparatus of the internal combustion engine which concerns on the modification of Example 1. FIG. It is a figure which shows the heat transport amount with respect to the load of an internal combustion engine provided with the intake / exhaust valve apparatus of the internal combustion engine which concerns on the modification of Example 1. FIG. It is a flowchart of control of the intake / exhaust valve device of the internal combustion engine according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 5 Cylinder head 6 Cylinder block 7 Intake port 8 Exhaust port 9 Spark plug 10 Piston 11 Combustion chamber 12 Cam 20 Intake / exhaust valve device 21 Lifter 22 Spring 23 Valve guide 25 Hollow valve 26 Intake valve 27 Exhaust valve 28 Valve stem 29 Umbrella part 30 Valve surface 31 Hollow part 35 Refrigerant 40 Temperature sensor 45 Knock sensor 50 Auxiliary cooling path 51 Auxiliary cooling oil path 52 Auxiliary cooling oil pipe 53 Oil jet 60 Auxiliary cooling oil pump 61 Auxiliary cooling water valve 62 Auxiliary cooling oil pump Cooling water passage 70 Oil passage 71 Oil pump 80 ECU
81 Storage Unit 82 Processing Unit 83 Memory 84 CPU
85 Input circuit 86 Output circuit 91 Amount of heat transported during auxiliary cooling 92 Amount of heat transported during non-auxiliary cooling 95 Valve temperature during auxiliary cooling 96 Valve temperature during non-auxiliary cooling 100 Valve guide 101 Valve guide cooling section 102 Radiation fin 111 Auxiliary cooling status line 112 Auxiliary Valve temperature at the time of cooling adjustment 113 Valve temperature at the time of non-adjustment of auxiliary cooling 121 Heat transfer amount at the time of auxiliary cooling adjustment 122 Heat transfer amount at the time of no auxiliary cooling adjustment

Claims (9)

The valve stem has an umbrella portion forming a part of the combustion chamber at one end, and at least a hollow portion is formed in the valve stem, and a refrigerant is sealed in the hollow portion, and the refrigerant is an internal combustion engine. An intake / exhaust valve device for an internal combustion engine provided with a hollow valve that recirculates according to the operating state of
Valve temperature detecting means for detecting the temperature of the hollow valve;
A valve cooling means for cooling the hollow valve when the temperature detected by the valve temperature detection means is higher than a predetermined temperature;
An intake / exhaust valve device for an internal combustion engine, comprising: The valve cooling means has a first cooling means and a second cooling means,
The second cooling means cools at least one of the valve stem or a valve guide that slidably supports the valve stem,
The intake / exhaust valve for an internal combustion engine according to claim 1, wherein the first cooling means cools the second cooling means when at least the temperature detected by the valve temperature detecting means is higher than a predetermined temperature. apparatus.   The second cooling means has a second cooling means refrigerant sealed therein, and the second cooling means refrigerant flows back according to the temperature of the second cooling means. An intake / exhaust valve device for an internal combustion engine according to claim 1. The combustion chamber is provided with a spark plug,
Comprising a valve temperature change rate determination means for detecting a temperature change rate of the hollow valve from the temperature of the hollow valve detected by the valve temperature detection means,
The valve temperature change rate determination means retards the ignition timing of the spark plug when the temperature of the hollow valve decreases at a decrease rate equal to or higher than a predetermined decrease rate. The intake / exhaust valve device for an internal combustion engine according to any one of the above. Comprising a valve temperature change rate determination means for detecting a temperature change rate of the hollow valve from the temperature of the hollow valve detected by the valve temperature detection means,
The valve temperature change rate determining means changes the air-fuel ratio of the fuel and air taken into the combustion chamber in a rich direction when the temperature of the hollow valve decreases at a rate that is equal to or greater than a predetermined rate of decrease. The intake / exhaust valve device for an internal combustion engine according to any one of claims 1 to 3. Comprising a valve temperature change rate determination means for detecting a temperature change rate of the hollow valve from the temperature of the hollow valve detected by the valve temperature detection means,
The said valve temperature change rate determination means increases a valve overlap period, when the temperature of the said hollow valve falls by the fall rate more than a predetermined fall rate, The valve overlap period is increased. The intake / exhaust valve device for an internal combustion engine according to the item. A cooling performance adjusting means for adjusting the cooling performance of the valve cooling means;
The intake / exhaust valve device for an internal combustion engine according to any one of claims 1 to 6, wherein the cooling performance of the valve cooling means is adjusted by the cooling performance adjusting means in accordance with an operating state of the internal combustion engine. . A load detecting means for detecting a load of the internal combustion engine;
8. The intake / exhaust valve device for an internal combustion engine according to claim 7, wherein the cooling performance of the valve cooling means is adjusted by the cooling performance adjusting means in accordance with the load of the internal combustion engine detected by the load detecting means. A knock detecting means for detecting knocking during combustion of fuel in the combustion chamber;
The intake / exhaust valve device for an internal combustion engine according to any one of claims 1 to 8, wherein the hollow valve is cooled when knocking in the combustion chamber is detected by the knock detection means.

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