JP2004044452A - Supercharger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent oil mist from adhering to a diffuser part, and also prevent a carbonized layer from being formed on the diffuser part. <P>SOLUTION: The diffuser part 28 of this supercharger comprises a diffuser flow passage 31 and a seal plate adjacent part and a housing adjacent part opposed to each other through the diffuser flow passage. Oil repellent films 45 and 46 are formed on the seal plate adjacent part and the housing adjacent part. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a supercharger used in a supercharged engine that increases the supply pressure of an internal combustion engine and increases the output of the internal combustion engine.
[0002]
[Prior art]
BACKGROUND ART In an automobile using a vehicle engine using an internal combustion engine having a supercharger, exhaust gas is circulated to combustion air in order to remove nitrogen oxides in the exhaust gas. Therefore, a part of the combustion air sucked by the supercharger contains exhaust gas. Here, the supercharger will be described with reference to FIG.
[0003]
A turbine housing 2 and a compressor housing 3 are coaxially connected on both sides of the bearing housing 1, and a turbine shaft 4 is rotatably supported on the bearing housing 1 via a bearing 5. A turbine wheel 6 housed in the turbine housing 2 is fixed to the portion, and a compressor wheel 7 is fixed to the other end of the turbine shaft 4.
[0004]
A bearing support 10 is formed inside the bearing housing 1, and the bearing 5 is fitted to the bearing support 10. A cavity 8 is formed around the bearing support 10, and an oil drain hole 9 communicating with the cavity 8 is formed below the bearing housing 1. A lubricating oil introduction hole 11 is drilled at a required position of the bearing housing 1, an oil passage 12 and a through hole 13 are drilled in the bearing support 10, and the oil passage 12 is formed in the lubricating oil introduction hole 11. The lubricating oil communicates with the bearing 5, and the through hole 13 discharges the lubricating oil flowing out of the bearing 5 to the cavity 8.
[0005]
The lubricating oil introduction hole 11 communicates with a lubricating oil circulation circuit (not shown) of the engine, and the oil discharging hole 9 is connected to an oil cooler of the lubricating oil circulation circuit.
[0006]
A cooling water flow path 14 is formed along a joint surface of the bearing housing 1 with the turbine housing 2, and the cooling water flow path 14 communicates with a cooling water circulation circuit (not shown) of the engine.
[0007]
The turbine housing 2 has a scroll passage 15 formed around the turbine wheel 6, and the scroll passage 15 communicates with the turbine wheel 6 via an annular gas flow path 16. Further, an exhaust port 17 concentric with the turbine wheel 6 is formed in the center of the turbine housing 2.
[0008]
The annular gas flow path 16 is provided with a required number of nozzle vanes 18 at a required pitch along the circumference so as to be rotatable via a shaft 19 parallel to the turbine shaft 4. The synchronous connection mechanism 21 is connected to a nozzle vane angle adjustment shaft 22. The nozzle vane angle adjusting shaft 22 is rotated by an actuator (not shown). The actuator rotates the nozzle vane angle adjusting shaft 22 by an angle corresponding to the engine speed. The rotation of the nozzle vane angle adjusting shaft 22 is controlled by the synchronous coupling mechanism 21. Through the shaft 19.
[0009]
The compressor housing 3 is composed of a seal plate 24 concentrically fixed to the bearing housing 1 and a housing body 25 concentrically fixed to the seal plate 24. A ring channel 26 is formed around the compressor wheel 7. The structure is formed. A discharge hole 27 communicates with a required position of the annular channel 26, and the discharge hole 27 communicates with a combustion chamber side of an engine (not shown). A suction hole 23 is formed at the center of the housing body 25 so as to face the compressor wheel 7 and concentric with the compressor wheel 7.
[0010]
Around the compressor wheel 7, a diffuser portion 28 communicating with the annular channel 26 is formed.
[0011]
The diffuser portion 28 includes an introduction wall portion 29 facing the seal plate 24 and a diffuser flow passage 31 formed between the seal plate 24 and the introduction wall portion 29. The introduction wall portion 29 is a part of the housing body 25. And a part of the flow path wall of the annular flow path 26.
[0012]
Exhaust gas from an engine (not shown) passes through the scroll passage 15 and the annular gas flow passage 16, passes through the turbine wheel 6, and is exhausted from the exhaust port 17. Then, the turbine wheel 6 is rotated. Further, the angle of the nozzle vane 18 is adjusted according to the engine speed, and the direction of the exhaust gas flowing into the turbine impeller 6 is adjusted by the nozzle vane 18, so that the energy of the exhaust gas is efficiently transmitted to the turbine impeller 6. It is well communicated.
[0013]
Due to the rotation of the turbine wheel 6, the compressor wheel 7 is rotated via the turbine shaft 4, and the combustion air is sucked through the suction hole 23. It is compressed by rotation and passing through the diffuser portion 28 and flows into the annulus channel 26. The compressed air is supplied to the engine (not shown) from the channel 26 through the discharge hole 27.
[0014]
Lubricating oil is supplied to the bearing 5 from the lubricating oil introduction hole 11, lubricates the rotating portion of the turbine shaft 4, and is discharged through the through hole 13, the cavity 8, and the oil drain hole 9. The lubricating oil lubricates the rotating part of the shaft and also cools the turbine shaft 4 and the bearing 5. The exhaust gas flowing through the turbine housing 2 has a high temperature, and the cooling water flowing through the cooling water passage 14 cools the joint portion of the bearing housing 1 with the turbine housing 2, and the heat from the turbine housing 2 is transferred to the bearing The transmission to the housing 1 is blocked.
[0015]
[Problems to be solved by the invention]
As described above, in the supercharger used for the engine with the supercharger, the blow-by gas is sucked, and the oil mist of the engine oil is mixed in the blow-by gas.
[0016]
The oil mist adheres to a portion of the diffuser portion 28 and the introduction wall portion 29 that is in contact with the diffuser flow path 31 in a process of passing through the diffuser portion 28. The temperature of the combustion air passing through the diffuser section 28 rises by being compressed, and becomes 120 ° C. or more. The adhering oil mist is carbonized by the heat of the compressed air, and may be solidified and deposited on the diffuser section 28 and the introduction wall section 29.
[0017]
Also, the solidified and deposited carbonized layer may narrow the diffuser flow path 31, increase the flow path resistance, and reduce the compression efficiency of the turbocharger. It is also conceivable that the carbonized layer is peeled off due to a difference in thermal expansion between the housing 3 and the carbonized layer, or vibration of the engine.
[0018]
In view of such circumstances, the present invention prevents oil mist from adhering to the diffuser portion and prevents a carbonized layer from being formed on the diffuser portion.
[0019]
[Means for Solving the Problems]
According to the present invention, the diffuser portion of the turbocharger is constituted by a diffuser flow path and a seal plate directing portion facing the diffuser flow path and the housing directing portion. The present invention relates to a supercharger having an oil-repellent film formed thereon, and the oil-repellent film relates to a supercharger formed by coating a fluororesin. The present invention relates to a supercharger in which a part is cooled.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0021]
The present invention is to prevent the oil mist from adhering to the diffuser portion 28, or to prevent the oil mist from staying when the oil mist adheres, and to prevent carbonization and accumulation even if the oil mist adheres.
[0022]
FIG. 1 shows a main part of a first embodiment of the present invention. In the drawing, the same components as those shown in FIG. 4 are denoted by the same reference numerals.
[0023]
The compressor housing 3 includes a seal plate 24 and a housing body 25, and the seal plate 24 is mounted concentrically on the bearing housing 1.
[0024]
One end of a turbine shaft 4 rotatably provided on the bearing housing 1 via a bearing 5 projects into the compressor housing 3, and a compressor wheel 7 is fitted to one end of the turbine shaft 4.
[0025]
A ring channel 26 having an open circumferential portion is formed in the housing body 25, and an introduction wall portion 29 forming a part of the channel channel 26 faces the seal plate 24, A diffuser passage 31 is formed between the inlet 24 and the introduction wall 29, and the diffuser 28 is constituted by the diffuser passage 31, the seal plate 24, and the introduction wall 29. The peripheral portion of the compressor wheel 7 is in contact with the center side end of the diffuser portion 28.
[0026]
At least a portion of the seal plate 24 in contact with the diffuser flow channel 31 (hereinafter referred to as a seal plate direct contact portion) and a surface of the introduction wall portion 29 in contact with the diffuser flow channel 31 (hereinafter referred to as a housing direct contact portion). The oil-repellent films 45 and 46 are formed of a material that repels oil mist having no affinity with engine oil.
[0027]
As a material of the oil-repellent films 45 and 46, for example, a fluororesin (polytetrafluoroethylene (CF2CF2) n) having excellent heat resistance and corrosion resistance is preferable, and the oil-repellent films 45 and 46 are coated with the fluororesin. Form.
[0028]
Hereinafter, the operation will be described.
[0029]
When the exhaust gas is introduced into the turbine housing 2, the compressor wheel 7 is rotated through the turbine shaft 4, and combustion air is sucked from the suction hole 23, and the sucked air is supplied to the compressor blade 2. It is compressed by the rotation of the vehicle 7, further compressed through the diffuser section 28, and flows into the annular channel 26. The compressed air flowing out of the discharge hole 27 through the annular passage 26 is supplied to an engine (not shown).
[0030]
As described above, the intake combustion air contains exhaust gas, and the exhaust gas contains oil mist of engine oil. The oil mist comes into contact with the oil-repellent films 45 and 46 in the process of passing through the diffuser section 28, but is repelled and flows out into the annular channel 26 without being attached.
[0031]
Therefore, even if the temperature of the compressed air rises to about 120 ° C., carbonization does not occur at the seal plate contact portion and the housing contact portion.
[0032]
Next, it has been found that the engine oil does not carbonize at about 120 ° C. and maintains fluidity. In the second embodiment, a rise in the temperature of the diffuser portion 28 is suppressed, and carbonization of engine oil is prevented.
[0033]
A second embodiment will be described with reference to FIGS.
[0034]
As described in connection with the prior art in FIG. 4, the joint of the bearing housing 1 and especially the joint of the bearing housing 1 with the turbine housing 2 is water-cooled. The supplied cooling water is further used for cooling the seal plate 24.
[0035]
Inside the seal plate 24, a cooling passage 33 is formed in a ring shape at a portion facing the diffuser passage 31. The cooling passage 33 is partially cut off and is not continuous over the entire circumference. A water conduit 34 and an outlet 35 are formed in the seal plate 24 so as to open at a joint surface with the bearing housing 1. The water conduit 34 communicates with a portion near one end of the cooling channel 33. The outlet path 35 communicates with the vicinity of the other end of the cooling path 33.
[0036]
A water supply port 36 and a drain port 37 (in FIG. 2, the water supply port 36 and the drain port 37 are respectively displaced in the circumferential direction), and an engine (not shown) is provided in the water supply port 36 and the drain port 37. Cooling water circulation circuit is connected.
[0037]
The water supply port 36 and the cooling water flow path 14 communicate with each other through a communication water path 38, and the cooling water flow path 14 and the drainage port 37 communicate with each other through another communication water path 39 (not shown). In addition, the water supply port 36 and the cooling passage 33 are fluid-tightly communicated with each other via a communication water passage 41 and the water conveyance passage 34, and the cooling passage 33 and the water discharge port 37 are connected to the outflow passage 35 and other communication water passages. It communicates in a liquid-tight manner via 42 (not shown).
[0038]
Although the lubricating oil introduction hole 11, the oil passage 12, and the like (see FIG. 4) are not shown in FIG. 1, the lubricating oil supply hole 36, the drain outlet 37, the communication water passage 38, the communication water passage 39, etc. do not interfere. Needless to say, it is provided in.
[0039]
Cooling water is introduced from the water supply port 36, and a part of the cooling water flows into the cooling passage 33 through the connecting water passage 41 and the water guiding passage 34, flows through the cooling passage 33, and flows out of the outlet passage 35, the connecting water passage. It flows out of the drain 37 via 42 (not shown).
[0040]
When the cooling water flows through the cooling passage 33, a portion of the seal plate 24 in contact with the diffuser flow path 31 (hereinafter, a seal plate contact portion) is cooled, and the seal plate contact portion is approximately 120 ° C. Temperature rise is suppressed. Even if the oil mist adheres to the seal plate contact portion, the oil mist does not accumulate on the seal plate, and the adhered oil mist maintains fluidity. It is.
[0041]
In addition, since the compressed air passing through the diffuser portion 28 is cooled by cooling the seal plate contact portion that is in contact with the diffuser flow path 31, the diffuser portion 28 is cooled through the compressed air, The rise in temperature of the diffuser section 28 is suppressed. Accordingly, the introduction wall portion 29 is not heated by the compressed air, and the oil mist attached to the housing contacting portion of the introduction wall portion 29 in contact with the diffuser passage 31 is also prevented from being carbonized and deposited.
[0042]
Thus, the temperature rise of the diffuser portion 28 and the compressed air passing through the diffuser portion 28 is suppressed, and the oil mist adheres to the seal plate contact portion and the housing contact portion of the diffuser portion 28 and is carbonized and deposited. Is prevented.
[0043]
In the second embodiment, the seal plate contact portion is cooled so that the adhering oil mist is not carbonized and deposited. Further, the oil-repellent films 45 and 46 shown in the first embodiment are formed. Then, the adhesion of the oil mist is suppressed, which is more effective.
[0044]
If the cooling path 33 has a sufficient effect of preventing the oil mist from being carbonized and deposited by cooling the contact portion of the seal plate, an oil-repellent film may be formed only on the contact portion of the housing.
[0045]
Also, the means for cooling the seal plate 24 is not a method of forming the cooling path 33 inside the seal plate 24, but a cooling pipe is attached to the outer surface of the seal plate 24, and the cooling path is formed through the cooling path formed by the cooling pipe. Various changes such as cooling the seal plate 24 are possible. Further, a cooling passage may be formed in the housing contact portion to cool the housing contact portion. Further, although the water supply to the cooling passage 33 is performed through the bearing housing 1, a cooling water supply pipe may be directly connected to the cooling passage 33.
[0046]
【The invention's effect】
As described above, according to the present invention, the diffuser portion of the supercharger is constituted by the diffuser passage, the seal plate contact portion facing the diffuser passage and the housing contact portion, and the seal plate contact portion. Since the oil repellent film is formed on the housing contact portion, the oil mist in the compressed air is prevented from adhering to the seal plate contact portion and the housing contact portion, and carbonization and accumulation of the oil mist is prevented. Further, since a cooling path is provided at least in the seal plate contact portion to cool the seal plate contact portion, a temperature rise in the seal plate contact portion is suppressed, and oil mist is reduced in the seal plate contact portion. Even when it adheres to the part, it exhibits an excellent effect of preventing carbonization of the oil mist.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a main part showing a first embodiment of the present invention.
FIG. 2 is a sectional view of a main part showing a second embodiment of the present invention.
FIG. 3 is a view as viewed in the direction of arrows AA in FIG. 2;
FIG. 4 is a sectional view of a conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Bearing housing 2 Turbine housing 3 Compressor housing 4 Turbine shaft 7 Compressor impeller 24 Seal plate 25 Housing main body 28 Diffuser part 29 Introducing wall part 31 Diffuser passage 33 Cooling path 36 Water supply port 37 Drain port 45 Oil repellent film 46 Oil repellent film

Claims (3)

The diffuser portion of the turbocharger is composed of a diffuser flow path, a seal plate contact portion and a housing contact portion facing each other across the diffuser flow passage, and an oil-repellent film is formed on the seal plate contact portion and the housing contact portion. A supercharger characterized by the following. 2. The supercharger according to claim 1, wherein said oil-repellent film is formed by coating a fluorine resin. 2. The supercharger according to claim 1, wherein a cooling passage is provided at least in the seal plate contact portion to cool the seal plate contact portion.

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