JPH022883Y2 - - Google Patents

Description

[Detailed description of the invention] [Technical field of the invention] This invention relates to an exhaust valve cooling device for an internal combustion engine that cools the exhaust valve by the heat of vaporization of a heat medium sealed in the exhaust valve. This invention relates to a device that detects a decrease in the amount of the medium and automatically replenishes the heat medium from the chamber.

[Technical background of the invention] FIG. 1 shows an example of an exhaust valve cooling device for an internal combustion engine proposed by the inventor of the present invention. To explain this, 1 is an exhaust valve, and a hollow chamber 3 for sealing a primary heat medium 2 is formed inside the exhaust valve.
A heat medium guide tube 6 communicating with is inserted. The valve head portion 7 exposed to the high temperature atmosphere is cooled by the heat of vaporization taken away when the primary heat medium in the hollow chamber 3 vaporizes, and the steam, which is the vaporized heat medium, flows from the hollow chamber 3 to the guide pipe 6. It is introduced into the heat exchanger 5 through the heat exchanger 5, where it is condensed and liquefied by heat exchange with the secondary heat medium 8, and returns to the hollow chamber 3 again, and the hollow chamber 3, the guide tube 6, and the heat exchanger 5 constitutes a heat medium circulation system for the primary heat medium.

The heat exchanger 5 is a mechanism that can rapidly control the heat exchange area of the heat exchanger 5 in order to maintain the temperature of the valve head portion 7 in an optimum state in accordance with fluctuations in the heat load of the internal combustion engine. That is, the cooling water 8, which is a secondary heat medium that indirectly exchanges heat with the steam introduced into the heat exchanger 5, is
A water cooling layer 10 is formed in the pressure regulating chamber 9 that accommodates this, and the height of the water cooling layer 10 can be adjusted by a pressurized air layer 11 formed above the water cooling layer 10. This makes it possible to increase or decrease the contact area (heat exchange area) between the steam and the secondary heat transfer medium.

This increase/decrease in the heat exchange area is performed by adjusting the pressure balance between the secondary heat medium and the pressurized air using a pressure regulating means consisting of a pressure regulating valve 12, a throttle valve 13, and a flow rate controlling valve 14. is now controlled by variations in the heat load of the internal combustion engine. Various sensors are provided at various parts of the cooling device, including the exhaust valve 1, in order to detect changes in the heat load of the internal combustion engine. The exhaust valve 1 has its valve stem 1
A valve temperature sensor 16, for example, a thermocouple, is provided along the surface of the valve head portion 7 from 5 to 7 for detecting the exhaust valve temperature. The guide tube 6 is provided with a steam temperature sensor 17, such as a thermocouple, for detecting the temperature in the hollow chamber 3, and a pressure sensor 18, such as a resistance pressure gauge, for detecting the pressure in the hollow chamber 3. . The heat exchanger 5 is also provided with a water level sensor 19 for detecting the water level of the cold water tank. This water level sensor 19 communicates with the outside of the pressure regulating chamber 9 at its upper and lower parts, and forms an upright water level in which, like the pressure regulating chamber 9, a double layer of a pressurized air layer 11 and a water cooling layer 10 is formed inside. A pipe 20 and a seal ring 2 on this water level pipe 20.
The scale 23 is inserted from the top through the water cooling layer 1 and moves up and down according to the water level of the water cooling layer 10 by means of a float 22 provided at the lower end, and a photoelectric lamp 24 reads the scale of this scale 23.
The height of 0 can be detected at all times. In addition, 25 is a heat-fusible plug for safety.

The exhaust valve temperature is detected directly or indirectly by these valve temperature sensor 16, steam temperature sensor 17, pressure sensor 18, and water level sensor 19, and the steam pressure regulating means is controlled based on the detected value. This makes it possible to control the temperature of the exhaust valve 1, which allows the exhaust valve temperature to be properly cooled regardless of changes in heat load, and prevents the exhaust valve from becoming overcooled and causing low-temperature corrosion, or due to temperature rise. This prevents the jamming phenomenon from occurring in the exhaust valve.

[Problems with the Background Art] However, since the connection between the exhaust valve 1 and the guide pipe 6 is required to be sealed while allowing the exhaust valve 1 to move up and down in the axial direction and rotate around the axis, Upper end opening 4 of hollow chamber 3 into which guide tube 6 is inserted
Since the seal ring 25 must be interposed on the inner wall of the tank, the seal ring 25 will wear out over a long period of use, and the reduction in steam due to leakage caused by the wear cannot be avoided due to the structure. For this reason, even if you try to control the temperature of the exhaust valve according to the fluctuations in the heat load of the internal combustion engine, the presence of a heat medium is a prerequisite, so if you do not notice the leakage and leave it, the exhaust valve 1 will stop due to the lack of heat medium. Sufficient cooling of the valve head portion 7 is no longer possible, and the valve head portion 7 becomes high in temperature, resulting in a decrease in strength, and there is a great risk of damage due to high-temperature corrosion caused by vanadium or the like.

[Purpose of the invention] This invention was created in view of the above problems.
The purpose is to obtain an exhaust valve cooling system for an internal combustion engine that can effectively prevent the inability to cool the exhaust valve due to a lack of heat medium due to leakage, and improve the reliability and life of the exhaust valve as much as possible. be.

[Summary of the invention] In order to achieve the above object, this invention is designed to condense the heat medium sealed in an exhaust valve that moves up and down, evaporate there, and then condense it in a heat exchanger that is slidably connected to the exhaust valve. In the exhaust valve cooling device for an internal combustion engine, the exhaust valve cooling device for an internal combustion engine has a heat medium circulation system that cools the exhaust valve by returning the heat medium to the exhaust valve. The apparatus is characterized by comprising a heating medium replenishing means for replenishing the heating medium stored in the chamber into the system based on the detection result of the detection means. This makes it possible to automatically replenish the reduced amount of heat medium leaked from the connection between the exhaust valve and the heat exchanger, and prevents high-temperature corrosion from occurring due to insufficient cooling due to lack of heat medium.
This is to prevent failure of cooling.

[Embodiment of the invention] Hereinafter, a preferred embodiment of the exhaust valve cooling device for an internal combustion engine according to the invention will be described with reference to the accompanying drawings.

FIG. 2 is a partially cutaway schematic structural diagram of the main part showing the first embodiment of this invention.

As shown in the figure, the heat exchanger 5 is provided with a heat medium replenishing means 30 for replenishing the heat medium 2 into the heat exchanger 5. The heat medium replenishing means 30 communicates with the lower header 31 of the heat exchanger 5, and includes a feed pipe 32 for feeding the heat medium thereto, and a chamber 33 for storing a predetermined amount of the heat medium is interposed in the middle thereof. has been done. This chamber 33 has a sealed structure, and when a heat medium is forcibly pumped into this chamber 33, a non-condensable gas in the chamber 33, such as air or an air-filled rubber balloon 34, is compressed, and this compression generates gas. The repulsive force of the non-condensable gas automatically pushes down the heat medium in the chamber 33 when the pressure of the heat medium is released. Further, the outer periphery of the chamber 33 is provided with the heat medium 2 inside the chamber 33.
Cooling fins 35 are provided for air cooling. The feed pipe 32 upstream and downstream of the chamber 33 has first and second pipes for opening and closing this pipe.
On-off valves 36 and 37 are interposed, respectively, and are successively opened and closed by a controller 38, which will be described later.

As shown in FIG. 3, the existing valve temperature sensor 16, steam temperature sensor 17, pressure sensor 18, and water level sensor 19 are electrically connected to the input of the controller 38, and the valve temperature signal, steam temperature signal, and steam A pressure signal and a water level signal are input to the controller 38. The output side of the controller 38 is connected to the first and second on-off valves 3.
6 and 37, and controls the opening and closing of the first and second on-off valves 36 and 37 by issuing an on-off signal.

To explain the function of the controller 38, it indirectly determines that there is a shortage of steam in the system from the valve temperature signal, steam temperature signal, steam pressure signal, or water level signal, and first injects a predetermined amount into the chamber 33. It outputs an opening/closing signal that opens for the time necessary for the heat medium to accumulate, and then closes again, and then opens for a time sufficient for the heat medium in the chamber 33 to be pushed down by the repulsive force of the non-condensable gas and all to be exhausted. After that, it outputs an opening/closing signal to close again.

Next, the operation of the above embodiment will be explained.

When the steam in the system decreases due to wear of the seal ring 25 interposed between the exhaust valve 1 and the guide pipe 6,
A controller 38 receives various signals from the valve temperature sensor 16, steam temperature sensor 17, steam pressure sensor 18, and water level sensor 19 and operates. That is, even though the water level sensor 19 detects the water level of the water cooling layer 10 in the heat exchanger 5 and the water level is sufficiently high and the cooling water is flowing, the valve temperature sensor 16 attached to the valve head part 7 shows no indication. If the valve temperature and the steam temperature indicated by the steam temperature sensor 17 in the hollow chamber 3 are abnormally higher than the initial normal temperature, it is considered from experimental results that the secondary heat medium in the system is extremely low. It will be done.
In such a case, the cooling capacity will be reduced due to the lack of heat medium, and the temperature of the valve head portion 7 will exceed a predetermined temperature.
37 is opened and closed as follows.

First, the first on-off valve 36 is opened to force-feed the heat medium, which is the replenishment liquid, to the chamber 33, and the first on-off valve 36
Close. Next, when the second on-off valve 37 is opened, the heat medium in the chamber 33 is pushed out by the non-condensable gas pressure and enters the lower header 31 of the heat exchanger 5, replenishing the amount of heat medium reduced due to leakage. do. Therefore, when replenishing the heat medium directly into the heat exchanger 5, even if the heat medium is fed at low pressure, it is not possible to replenish the heat medium in a fixed amount due to the influence of pressure fluctuations within the heat exchanger 5. A certain amount of water to be replenished is stored in the chamber 33 with the on-off valve 37 of No. 2 closed and communication with the heat exchanger 5 cut off.
Since the heat medium in the chamber 33 is replenished by communicating the heat exchanger 5 with the heat exchanger 5, it is possible to replenish a fixed amount of the heat medium regardless of pressure fluctuations in the heat exchanger 5. In addition, the replenishment of the steam heat medium is handled by a controller 3 that constantly receives signals from various sensors and makes decisions.
Since it is controlled by 8, it can be performed automatically even during driving. As a result, situations such as inability to cool due to heat medium leakage are avoided, and appropriate temperature control of the exhaust valve can be ensured in response to fluctuations in thermal load, so the life of the exhaust valve can be significantly extended. Furthermore, even if the seal ring 25 between the exhaust valve 1 and the guide pipe 6 is damaged, the heat medium will continue to be replenished, so the amount of heat medium necessary for cooling can be secured in the system, and operation can be resumed immediately. There is no need to stop the process, and it is possible to prevent secondary damage from occurring to other components, devices, products, etc., thereby improving reliability as much as possible. Furthermore, the existing controllers and sensors can be used as is, and the heating medium can be refilled automatically by adding a small amount of heating medium replenishment means, so cost performance is extremely high, while maintenance costs are extremely low. There is.

Figure 4 shows a second embodiment of this invention.
The difference from the first embodiment is that the chamber is a cylinder 40.
As compressed air 41 pressure or spring 42 inside it
The point is that a piston 43 is provided to push down the heat medium 2 that has been pumped into the cylinder 40 by the restoring force of the cylinder 40 and forcibly discharge it from the cylinder 40. When compressed air 40 is used, it is necessary to provide an air supply pipe 44 for supplying the compressed air and a third on-off valve 45 for opening and closing the air supply pipe 44. This third on-off valve 45 is connected to the controller 3 described above.
8. To explain the operation of this embodiment, the first on-off valve 36 is opened in order to temporarily store the heat medium in the cylinder 40. The piston 43 is pushed by the pressure of the pumped heat medium and moves upward.
At this time, the air on the back side of the piston 43 is released to the atmosphere through a relief hole 46 provided adjacent to the third on-off valve 45. When the heat medium 2 has sufficiently accumulated in the cylinder 40, the first on-off valve 36 is closed, and the third and second on-off valves 45 and 37 are sequentially opened. Then, the heat medium in the cylinder 40 is pushed by the piston 43 that descends due to compressed air, is discharged from the cylinder 40, and is replenished into the heat exchanger 5. According to this, unlike the case of the first embodiment, the cylinder 40
Since the heat medium inside can be forcibly discharged, when the pressure inside the heat exchanger 5 is high and the length of the feed pipe 32 connecting the cylinder 40 and the heat exchanger 5 is long,
Alternatively, if the pipe system of the feed pipe 32 is thin, or furthermore, if the heat medium in the pipe is difficult to flow, the heat medium 2
It has the advantage that it can be applied in cases where it is difficult to replenish the heat exchanger 5 with only the pressure accumulated in the heat exchanger 5.

Figure 5 shows the third embodiment of this invention.
The difference from the second embodiment is that the piston 43 is replaced by an electric motor 5.
The piston 43 is screwed onto the drive shaft 51 of the heat exchanger 5 so that the piston 43 can be moved up and down by the rotation of the drive shaft. It has the advantage that it can be applied even when the vapor pressure of is not constant and is quite high. Note that the electric motor 50 is of course controlled by a controller.

In addition, in all of the embodiments described above, the heat medium is supplied to the heat exchanger 5, but it may be supplied to the hollow chamber 3 or the guide pipe 6, and in short, it may be supplied anywhere within the heat medium circulation system. .

[Effects of the invention] In summary, this invention provides the following excellent effects.

(1) A decrease in the heat medium in the heat medium circulation system is detected and the heat medium is replenished from the chamber.
The inability to cool the exhaust valve due to lack of heat medium can be effectively avoided. Therefore, the exhaust valve temperature can be maintained appropriately and the life of the exhaust valve can be significantly extended.

(2) Even if the sealing performance of the connection between the exhaust valve and the heat exchanger is impaired, there is no need to immediately stop operation of the internal combustion engine, as the leaked heat medium will be replenished. Secondary damage to other components, equipment, products, etc. can be prevented and reliability is improved.

(3) Since the heat medium is supplied into the system after passing through the chamber, the heat medium can be stably supplied regardless of pressure fluctuations within the system.

[Brief explanation of drawings]

Fig. 1 is a schematic longitudinal sectional view of the entire exhaust valve cooling system for an internal combustion engine, which is the premise of this invention, and Fig. 2 is a partially cutaway view of the main parts showing the first embodiment of the exhaust valve cooling system according to this invention. , FIG. 3 is a block diagram explaining the input/output system of the control section, FIG. 4 is a partially cutaway view of the main part showing the second embodiment, and FIG. 5 is a main part showing the third embodiment. FIG. In the figure, 1 is an exhaust valve, 2 is a heat medium, 3, 5, and 6 are hollow chambers, heat exchangers, and heat medium guide pipes that constitute a heat medium circulation system, and 16, 17, 18, and 19 are heat medium A valve temperature sensor, a steam temperature sensor, a steam pressure sensor, and a water level sensor constituting a detection means for detecting a decrease; 30 is a heat medium replenishment means; 33 and 40;
is Chiyamba.

Claims (1)

[Scope of utility model registration request] Heat that is sealed in an exhaust valve that moves up and down and evaporates there is guided to a heat exchanger that is slidably connected to the exhaust valve, condensed, and returned to the exhaust valve to cool the exhaust valve. In the exhaust valve cooling device for an internal combustion engine having a medium circulation system, the circulation system includes a detection means for detecting a decrease in the heat medium in the system due to leakage from the connection part, and a detection means for detecting a decrease in the heat medium in the system due to leakage from the connection part, 1. An exhaust valve cooling device for an internal combustion engine, comprising a heat medium replenishing means for replenishing the stored heat medium into the system.