JPH0541234Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a cooling device for a wastegate port portion of a turbine housing of a turbocharger of an internal combustion engine.

[Conventional technology]

Regarding the cooling of turbochargers, as shown in Japanese Patent Publication No. 17095/1983, many lubrication and cooling structures for the bearing housings have been disclosed as prior art, but there have been no proposals for cooling methods for the turbine housings. None. As a related technology, the area around the waste gate valve stem is cooled with cooling water (utilized in 1982).
Publication No. 94433), air cooling of the actuator for opening and closing the waste gate valve (Utility Model Publication No. 62-
12830), a proposal to insulate the joint between the bearing and the turbine housing in order to block the transfer of heat to the bearing housing (Utility Model Publication No. 14347)
Publication No.) etc.

[Problems that this invention attempts to solve]

There is no problem in current daily general driving conditions, but when driving under severe cold and heat durability,
The waste gate valve is thermally distorted and the first
Due to the difference in elongation in the X-Y directions shown in the figure, the flatness of the valve becomes poor, which reduces the degree of sealing in the closed state of the wastegate valve, which is thought to be a problem that leads to deterioration of acceleration characteristics. . The purpose of the present invention is to correct the uneven temperature difference caused by repeated heating and cooling, which causes the difference in elongation in the X-Y direction.

[Means for solving problems]

In order to solve the above-mentioned problems, in the present invention, in a turbine housing of a turbocharger having a structure in which a wastegate port is provided in the turbine housing, a cooling device is installed inside the valve seat of the wastegate valve that opens and closes the wastegate port. A cooling device for a wastegate port of a turbine housing of a turbocharger of an internal combustion engine, which is configured to provide a medium passage and control the flow of the cooling medium into the passage according to the open/closed state of a wastegate valve. provide.

[Effect]

In the present invention, when the supercharging pressure of the turbocharger exceeds a set value and the wastegate valve opens, a detection signal of the wastegate valve opening is transmitted to the control valve that opens and closes the cooling medium passage. is opened, and a cooling medium is circulated inside the valve seat portion of the wastegate valve to prevent the temperature around the valve seat portion and wastegate port from increasing. Furthermore, when the engine shifts to low-load operation and the boost pressure falls below a set value, this state is detected, and a detection signal acts on the control valve to stop the flow of the cooling medium.

〔Example〕

As a reference for explaining the embodiments of the present invention, first, an example of the opening/closing mechanism of a waste gate valve of a conventional turbocharger will be explained with reference to FIGS. 7 and 8.
As shown in FIG. 8, the turbocharger 20 includes a turbine housing 1 and a compressor housing 21.
The engine is supercharged by passing exhaust gas G and air A into and out of the engine. As shown in FIG. 7, the waste gate valve 15 is a disc-shaped flapper valve.
The arm 13, the wastegate valve shaft 12 fitted to the bush 11, and the link 14 are operated to open and close the actuator 22. When the supercharging pressure to the engine exceeds the set value, the actuator 22 is actuated, and the wastegate valve 15 rotates around the valve shaft 12, stands upright in the direction perpendicular to the plane of the paper in FIG. 7, and is fully opened.
A part of the exhaust gas is discharged from the waste gate port 3 to the bypass passage, and the supercharging pressure is adjusted. In the present invention, the opening/closing mechanism of the waste gate valve is basically the same as the one described above, although there are differences in the operating method of the actuator, etc.

Next, embodiments of the present invention will be described based on the drawings.
1 and 2 show partial cross-sectional views of the turbine housing and wastegate valve portions of the first embodiment. 1 is a turbine housing, 2 is a hole for the turbine, 3 is a cooling medium passage provided around the wastegate port and flows through the inside of the valve seat portion 16 of the wastegate valve 15, and 5 is provided on the outer wall of the turbocharger. 6 is the inlet of the cooling medium passage, 6 is the outlet of the cooling medium passage, 7 is the control valve of the cooling device, 8 is a signal that detects the open/closed state of the waste gate valve, and turns ON when the waste gate valve opens and closes. Sometimes
OFF signal is input to valve 7, signal 8 is ON
When it is OFF, the valve 7 is open and refrigerant flows through the passage 4, and when it is OFF, the valve 7 is closed.

The signal 8 may be an actuator pressure signal for operating the wastegate valve, or a signal obtained by converting that pressure into an electric signal via a vacuum switching valve (VSV), or a signal that converts the displacement of the actuator shaft into a differential angle. It may also be a signal detected by a transformer.

9 is a refrigerant passage, 10 is a cooling unit, and the stored refrigerant R is engine cooling water, lubricating oil, or
It may also be a refrigerant for an intercooler for a turbocharger. FIG. 2 shows a partial cross section around the waste gate valve 15. As shown in FIG. Reference numeral 11 denotes a bush for a valve shaft 12 for transmitting the movement of an actuator for opening and closing the waste gate valve to the waste gate valve 15, and is fitted into the turbine housing 1. An arm 13 connected to a waste gate valve 15 is connected to the valve shaft 12, and an actuator (not shown) is connected to the valve shaft 12.
When the valve 15 opens due to the operation of the valve 15, it rotates around the shaft 12 as shown by the broken line in FIG. A part of the exhaust gas G is discharged to the bypass passage. At this time, the valve seat portion 16 of the waste gate valve 15 is heated due to the passage of exhaust gas, but at this time, the cooling medium R flows into the cooling medium passage 4 around the waste gate port 3 and the valve seat 16 is heated. To cool the seat portion 16 and prevent it from overheating.

Next, the results of experiments conducted on the operation of the cooling device by operating the turbocharger according to this embodiment will be explained. Temperature measurements during operation were made at three points □A, □B, and □C of the turbine housing shown in FIG. □A is the outside of the turbine hole 2, □B is the turbine hole 2 side of the waste gate port 3, and □C is the outside of the waste gate port 3 on the exhaust manifold flange side. The results are shown in FIG. Fourth
The figure shows the temperature distribution at points □A, □B, and □C according to each operating state. First, looking at the conventional case where the wastegate port section is not cooled, the line shows the results of normal low-load operation. At this time, the thicker parts □B and □C are lower in temperature than the □A part, where exhaust gas is constantly swirling and being discharged, and the temperature distribution in the case of low-load operation with an engine speed of 3500 rpm is as shown in the line. The result was as follows. Next, with this conventional type, the engine speed increases and the load becomes high,
When the boost pressure exceeds the set value, it becomes as shown by the line. At this time, the wastegate valve opens to prevent the compressor from overspeeding, and the high-temperature exhaust gas is transferred to the wastegate port 3.
is bypassed and discharged through the
Sections □A and □B were higher in temperature than section □C, which was in contact with the outside air. At this time, the temperature difference generated between □B and □C around the waste gate port 3 causes thermal distortion of the waste gate valve as described above, resulting in a malfunction.

Therefore, in the present invention, in order to prevent □B from becoming high temperature due to high-temperature exhaust gas when the boost pressure exceeds the set value and the wastegate valve opens, the wastegate valve opening detection is performed. The control valve 7 was actuated by the signal 8, and the cooling medium R was circulated around the waste gate port to prevent the temperature of □B from increasing. Furthermore, when the waste gate valve is closed after shifting to low load operation, this state is detected and a detection signal is applied to the control valve 7 to stop the flow of the cooling medium R.

The temperature distribution when the cooling device is activated when the waste gate valve according to the present invention is opened is shown by the line in FIG. Also, the engine speed when cooling is performed constantly regardless of the load level.
The line shows an example of temperature distribution during low load operation at 3500 rpm. In this case, since a large temperature difference occurs between the □A part and the □B part, there is a possibility that deformation cracks will occur on the □A part side.

Based on the above experimental results, the line □A, □B, □C based on the method of controlling the cooling system according to the opening and closing of the waste gate valve as shown in the present invention was found to be higher than the other lines.
It was found that the temperature gradient in this area was the gentlest, and that it was highly effective against the aforementioned thermal deformation.

In addition, if a time delay is added to the input of the ON/OFF detection signal, and the cooling system is operated for a while after the wastegate valve changes from opening to closing, it is possible to Differences in temperature changes in each part due to heat capacity can be corrected, resulting in more precise control. This delayed operation can be achieved by delaying the pressure signal acting on the actuator using a vacuum time relay valve (VTV), or by detecting an electrical signal and controlling the timer.

In addition, in the examples above, digitally ON,
Although we have explained the control to turn off the power, similar results were obtained even if this was controlled analogously. This may be controlled by a method in which the detection signal is replaced by mechanical displacement, that is, by a needle for controlling the opening area of the valve 7 that is linked with the shaft of the actuator. FIG. 5 shows an example of analog control. As shown in the figure, the waste gate valve 15 of the turbocharger 20 is opened and closed by an actuator 22, and an actuator 24 of the same type as the actuator 22 is operated by the same vacuum source as the actuator 22, and moves the valve body 26 in the control valve 7 back and forth. The flow rate of the cooling medium R is adjusted by increasing or decreasing the gap between the waste gate valve 15 and the valve seat 28.
The flow rate of the cooling medium R is controlled in an analog manner according to the opening degree of the cooling medium R.

FIG. 6 shows a second embodiment of the present invention. In this example, the arrangement of the cooling medium passage 4 is changed to bush 1.
It is placed near 1. This is effective in preventing the shaft 12 of the wastegate valve from twisting due to high temperatures, which is another cause of poor valve sealing. The other configurations and functions are the same as those in the first embodiment, so their explanations will be omitted.

As described above, the thermal gradient around the waste gate port 3 can be made gentler, the thermal distortion of the waste gate port can be reduced, and its operation can be performed reliably.

[Effect of idea]

Since the present invention has the above-described structure and operation, when the waste gate valve is opened, the valve seat portion of the waste gate valve and the housing around the waste gate port are cooled, thereby cooling the area around the port. This has the effect of correcting the uneven temperature difference, thereby preventing poor sealing of the wastegate valve due to thermal distortion, and preventing deterioration of operating performance such as acceleration characteristics of the engine.

[Brief explanation of the drawing]

Fig. 1 is a front view of a turbine housing and a refrigerant passage according to a first embodiment of the present invention, Fig. 2 is a cross-sectional side view of a part of Fig. 1, and Fig. 3 is an explanatory diagram of temperature distribution measurement points of the turbine housing. , Figure 4 is a temperature distribution diagram of the turbine housing, Figure 5 is an explanatory diagram when the refrigerant flow rate is analog controlled, and Figure 6 is a diagram of the temperature distribution of the turbine housing.
FIG. 7 is a layout diagram of a cooling medium passage according to an embodiment, FIG. 7 is a layout diagram of a waste gate valve of a conventional example, and FIG. 8 is an overall side view of FIG. 7. 1... Turbine housing, 3... Waste gate port, 4, 9... Cooling medium passage, 11
...Button, 12...Wastegate valve shaft, 15...Wastegate valve, 1
6... Valve seat portion, 20... Turbo charger, 22, 24... Actuator, R... Cooling medium.

Claims (1)

[Scope of utility model registration request] In a turbine housing of a turbocharger having a waste gate port in the turbine housing, a cooling medium passage is provided inside a valve seat portion of a waste gate valve that opens and closes the waste gate port, and the cooling medium is controlled according to the open/close state of the waste gate valve. A cooling device for a wastegate port of a turbine housing of a turbocharger of an internal combustion engine, configured to control flow of the cooling medium into the passageway.