JP7388946B2 - exhaust turbo supercharger - Google Patents

Description

The present invention relates to an exhaust turbo supercharger installed in an internal combustion engine.

2. Description of the Related Art In internal combustion engines for vehicles and the like, it is widely practiced to provide an exhaust turbo supercharger in order to improve output and the like. This exhaust turbo supercharger includes a turbine housing, a compressor housing, and a bearing housing. Inside the turbine housing, there is a turbine scroll passage (turbine scroll chamber) whose cross-sectional area decreases in the direction of rotation of the turbine blades. , an exhaust gas introduction passage communicating with the starting end of the turbine scroll passage, and an exhaust gas outlet passage opening in the direction of the rotational axis of the turbine blade.

In an exhaust turbo supercharger, in order to increase supercharging efficiency, it is preferable to allow exhaust gas to flow into the turbine scroll passage without lowering its temperature as much as possible. In addition, in automotive gasoline engines, a catalytic exhaust gas purification device is placed downstream of the exhaust turbo supercharger, but the catalyst has the property of not being activated unless the temperature rises to a certain level, so In order to quickly raise the temperature of the catalyst during engine operation, it is preferable that the exhaust gas passes through the turbine housing without lowering its temperature as much as possible. Furthermore, it has been proposed to make the housing of the exhaust turbo supercharger aluminum to improve fuel efficiency, but since aluminum has low heat resistance, it is preferable for weight reduction if heat damage from exhaust gas can be suppressed.

As a countermeasure to these demands, it is conceivable to provide the turbine housing with a heat insulating layer that suppresses the heat of exhaust gas from being transmitted to the turbine housing. Regarding this point, Patent Document 1 discloses that the inside of the turbine scroll passage is constructed of a composite body consisting of a heat-resistant surface layer made of ceramic or stainless steel plate and a heat insulating layer such as heat insulating fiber. In Document 1, the composite is set together with a core in a mold and cast.

Microfilm of Utility Model No. 60-24839

In Patent Document 1, the heat insulation of the turbine scroll passage can be improved, but since the structure is extremely complicated, it cannot be denied that the cost increases. In addition, the turbine housing has gas passages such as the exhaust gas introduction passage, wastegate passage, and exhaust gas outlet passage, but since heat transfer from these other passages cannot be suppressed, when looking at the turbine housing as a whole, It is questionable whether high insulation properties can be ensured.

Furthermore, there is some clearance between the turbine blades and the turbine scroll passage, and the management of this clearance is an important factor that affects the performance of the exhaust turbocharger. It is highly questionable whether the turbine scroll passage can be formed with high precision in a configuration in which the heat insulating composite is cast.

The present invention has been made against the background of the current situation, and aims to provide an exhaust turbo supercharger that has excellent heat insulation properties and supercharging performance, and is stable in quality.

The exhaust turbo supercharger of the present invention is
"Inside the turbine housing, a turbine scroll passage surrounding the turbine blade, an exhaust gas introduction passage communicating with the starting end of the turbine scroll passage, an exhaust gas outlet passage opening in the direction of the rotational axis of the turbine blade, and the exhaust gas A waste gate passage communicating with the gas introduction passage and the exhaust gas outlet passage is formed,
An exhaust turbo supercharger in which a heat insulating layer made of a heat insulating material having a hardness that can be cut by rotation of the turbine blade is formed in the turbine scroll passage,
The heat insulating layer of the turbine scroll passage is fired from a mixture of ceramic particles and a resin binder, and the resin binder is burned away by firing and the ceramic particles bond to each other to form a porous fired layer. It is layered,
Further, a heat insulating layer made of the same heat insulating material as the turbine scroll passage is also formed in the exhaust gas introduction passage, the exhaust gas outlet passage, and the waste gate passage.
The structure is as follows.

In this case, the heat insulating material can be an amorphous material made by mixing ceramic particles and a heat-resistant binder such as resin, and by immersing the turbine housing in a liquid insulating material tank, liquid insulating material can be applied to the entire inner surface of each passage. By applying the material and then curing it to harden it, an irremovably retained layer of insulation can be formed.

A thermal insulation layer can be formed over all or most of each passageway. In this case, " most" refers to the range where the turbine housing's heat insulation effect can be enjoyed; for example, if it is 80% or more, it can be said that the desired effect can be enjoyed (90% or more is preferable). be.).

In the present invention, since the passage through which the exhaust gas flows in the turbine housing is covered with the heat insulating layer, heat transfer from the exhaust gas to the turbine housing can be significantly suppressed, thereby suppressing the temperature drop of the exhaust gas. As a result, the supercharging efficiency can be improved, and when a catalytic exhaust gas purification device is connected, the temperature of the catalyst can be raised early especially during warm-up operation, contributing to improved exhaust gas purification performance. Furthermore, by being able to suppress the amount of heat received by the turbine housing, it can greatly contribute to making the turbine housing aluminum (lighter).

In addition, since the heat insulating material is hard enough to be cut by the turbine blades when provided in the turbine scroll passage , by setting the heat insulating material layer in the turbine scroll passage to a thickness that allows the turbine blades to come into contact with it, the turbine blades can be When installed and driven, the heat insulating material layer is cut by the turbine blades, and the minimum necessary clearance corresponding to each turbine blade can be automatically formed between the turbine scroll passage and the turbine blades. Therefore, an exhaust turbo supercharger that eliminates unnecessary leakage of exhaust gas and improves work efficiency can be provided with uniform quality.

Note that clearance adjustment by cutting the insulation layer with the turbine blade is done by blowing compressed air into the exhaust gas introduction passage after the exhaust turbocharger is assembled and before it is installed in the internal combustion engine. (Hot air may be blown into the exhaust gas introduction passage to simulate actual operation.)

FIG. 2 is a front view of an exhaust turbo supercharger according to an embodiment. FIG. 3 is a rear view of the exhaust turbo supercharger. FIG. 2 is a right side view taken along III-III in FIG. 1; FIG. 2 is a left side view taken along IV-IV in FIG. 1; It is a top view of an exhaust turbo supercharger. 5 is a sectional view taken along VI-VI in FIGS. 3 and 4. FIG. 7 is a partially enlarged view of FIG. 6. FIG. 7 is a sectional view taken along line VIII-VIII of FIGS. 2 and 6. FIG.

(1).Basic Structure Next, embodiments of the present invention will be described based on the drawings. This embodiment is applied to an exhaust turbo supercharger for an internal combustion engine for an automobile. First, the basic structure will be explained. Regarding the direction in relation to the internal combustion engine, FIG. 1 is a front view, which is viewed from a direction opposite to the intake side of a cylinder head (not shown). Therefore, the direction of the crank axis is the left-right direction, and the width direction of the cylinder head is the front-rear direction.

As can be understood from FIGS. 1 and 2, an exhaust turbo supercharger includes a turbine housing 1 in which turbine blades 2 driven by exhaust gas are disposed, and as can be understood in FIGS. 1 and 3, compressor blades 3 are disposed. The compressor housing 4 includes a compressor housing 4, and a bearing housing 5 located between the compressor housing 4 and the bearing housing 5. The turbine blades 2 are fixed to one end of the rotating shaft 6, and the compressor blades 3 are fixed to the other end of the rotating shaft 6. Therefore, the housings 1, 4, and 5 are arranged in the left-right direction.

As shown in FIG. 2, the turbine housing 1 is formed with an inlet flange 7 that is fixed to a cylinder head or an exhaust manifold (not shown). A gas introduction passage 8 opens rearward. As shown in FIG. 8, the exhaust gas introduction passage 8 communicates with a turbine scroll passage 9 surrounding the turbine blade 2, and as shown in FIGS. It has a shroud chamber 9a that rotates. The shroud chamber 9a is open in the direction of the rotational axis of the turbine blade 2, and communicates with the exhaust gas outlet passage 10. The exhaust gas outlet passage 10 opens into an outlet side flange 11 facing in the left-right direction.

Therefore, the turbine housing 1 includes a drum-shaped part 1a (see FIG. 1) that surrounds the turbine scroll passage 9, a cylindrical part 1b (see FIG. 3) in which the exhaust gas introduction passage 8 is formed, a drum-shaped part 1a , and a cylindrical part 1a (see FIG. 3). The side part 1c is provided with a side part 1c projecting from the shaped part 1b to the side opposite to the compressor housing 4, and the side part 1c has a waste gate passage 12 (Fig. 6) is formed. The end of the wastegate passage 12 is opened and closed by a wastegate valve 13.

As shown in FIG. 3, an arm 13a is fixed to the waste gate valve 13, and a longitudinal longitudinal support shaft 14 is fixed to the arm 13a. The support shaft 14 is rotatably held by the side portion 1c of the turbine housing 1, and a link 15 is fixed to an outwardly projecting portion.

As shown in FIG. 2, the link 15 is in a vertically longitudinal posture, and its upper end is fixed to the support shaft 14, and the tips of the left and right longitudinal rods 16 are connected to the lower end by the front and rear longitudinal pins 17. Rotatably connected. The rod 16 is fixed to a valve body (not shown) of an actuator 18 fixed to the compressor housing 4.

As can be clearly understood from FIGS. 3 and 6, in this embodiment, the cylindrical portion 1b of the turbine housing 1 extends obliquely upward from the inlet side flange 7, and the turbine scroll passage 9 and the turbine blades 2 are connected to the inlet side flange 7. It is placed above 7. Therefore, the exhaust turbo supercharger of this embodiment is of an upward winding type in which the exhaust gas flows upward.

As shown in FIG. 6, a compressor scroll chamber 19 is formed inside the compressor housing 4, and an intake inlet 20 (see FIG. 2) for supplying intake air to the compressor scroll chamber 19 opens in the axial direction. The intake air pressurized in the compressor scroll chamber 19 is discharged from an intake outlet 21 (for example, FIG. 4) that opens in a direction intersecting the rotation axis. As shown in FIG. 6, the compressor housing 4 includes an inner member 22 for forming the compressor scroll chamber 19. As shown in FIG.

As can be understood from FIG. 2, the actuator 18 is fixed to the actuator bracket 23 with screws (not shown), and the compressor housing 4 and the bearing housing 5 are connected to each other via the actuator bracket 23 and the holding plate 24. It has been concluded. Four bolts 25 are shown in FIG. 4, and the bearing housing 5 is held and fixed to the compressor housing 4 by attracting the actuator bracket 23 and the holding plate 24 with these bolts 25.

As shown in FIG. 6, a floating metal 26 that rotatably holds the rotating shaft 6 is loosely fitted inside the bearing housing 5. The bearing housing 5 has an oil inlet 27 that opens upward to supply oil to the floating metal 26, and an outlet port 28 that discharges oil that opens downward.

In this embodiment, in order to reduce weight, the turbine housing 1 and the bearing housing 5 are integrated as an aluminum cast product, and the compressor housing 4 is an aluminum die-cast product (even if it is a cast product). good.). Therefore, as shown in FIG. 6, cooling water jackets 31 and 32 are formed inside the turbine housing 1.

That is, the cooling water jacket is composed of a first cooling water jacket 31 located on the side of the bearing housing 5 and a second cooling water jacket 32 located on the side of the exhaust gas outlet passage 10, both of which are connected to the partition wall 33. It is separated by As shown in FIGS. 2 and 8, both cooling water jackets 31 and 32 are formed with branch passages 31a and 32a that open to the inlet side flange 7.

The first cooling water jacket 31 surrounds the turbine scroll passage 9 from the outer peripheral side and the bearing housing 5 side, and extends to the lower end of the cylindrical portion 1b. On the other hand, the second cooling water jacket 32 surrounds the exhaust gas outlet passage 10 and extends to the lower end of the cylindrical portion 1b. A cooling water inlet port 34 is provided at a portion near the lower end of the cylindrical portion 1b, and a cooling water outlet port 35 is provided at the upper end of the portion where the drum-shaped portion 1a and the side portion 1c are connected. Both ports 34 and 35 are connected to joints 36 and 37 (see, for example, FIG. 1) for fixing hoses.

(2).Insulation treatment As shown by thick lines in FIGS. 7 and 8, the entire surface of the exhaust gas introduction passage 8, the entire surface of the turbine scroll passage 9 including the shroud chamber 9a, the entire surface of the exhaust gas outlet passage 10, and the entire surface of the waste gate passage 12. A heat insulating material layer 38 is formed on the entire surface. Therefore, heat radiation from the exhaust gas to the turbine housing 1 is significantly suppressed. As a result, it is possible to improve supercharging efficiency by suppressing the expansion of exhaust gas, and it is also possible to contribute to early temperature rise of the catalyst disposed on the downstream side.

Furthermore, since the heat transfer from the exhaust gas to the turbine housing 1 is reduced, the amount of heat received by the cooling water is also reduced, so the amount of cooling water can be suppressed and the load on the water pump can be reduced. Therefore, it can also contribute to improving fuel efficiency.

The heat insulating material layer 38 is formed by firing ceramic particles (for example, hollow particles or porous particles). That is, by putting a mixture of ceramic particles and a liquid binder such as resin in a tank and immersing the turbine housing 1 in the tank, a heat insulating intermediate layer (coating) is formed on the inner surface of each exhaust gas passage. Next, the turbine housing 1 is placed in a heating furnace and heated at several hundred degrees to remove the binder and sinter (bond) the ceramic particles to form the heat insulating layer 38.

In this case, as shown by a dashed line 38a in the shroud chamber 9a in FIG. After assembling, the turbine blade 2 is rotated at high speed by sending compressed air to the exhaust gas introduction passage 8, and the heat insulating material layer 38 is cut by the turbine blade 2 (since the turbine blade 2 is made of a hard special alloy, The insulation layer 38 is cut by the turbine blade 2).

Since the turbine blades 2 swing slightly, a necessary minimum clearance corresponding to each turbine blade 2 is automatically formed between the turbine blades 2 and the turbine scroll passage 9 (particularly the shroud chamber 9a). Therefore, even if there is some misalignment between the turbine blade 2 and the shroud chamber 9a, or if there is a machining error or installation error in the turbine blade 2, these errors can be absorbed and no exhaust gas is required. It is possible to create a clearance with no leakage. As a result, an exhaust turbo supercharger with excellent supercharging efficiency can be manufactured without variation.

Although the above embodiment was applied to a water-cooled turbine housing made of aluminum, the present invention can also be applied to a turbine housing made of cast steel. In the illustrated embodiment, the shroud chamber is formed directly in the turbine housing 1, but it is also possible to attach a sleeve-shaped shroud piece to the exhaust gas outlet passage 10. In this case, a heat insulating layer 38 may be formed on the inner surface of the shroud piece, and the shroud piece may be cut by the turbine blade 2 after being attached.

The present invention can be embodied in an exhaust turbo supercharger. Therefore, it can be used industrially.

1 Turbine housing 2 Turbine blade 5 Bearing housing 6 Rotating shaft 8 Exhaust gas introduction passage 9 Turbine scroll passage 9a Shroud chamber 10 Exhaust gas outlet passage 12 Waste gate passage 13 Waste gate valve 38 Heat insulation layer

Claims (1)

Inside the turbine housing, a turbine scroll passage surrounding a turbine blade, an exhaust gas introduction passage communicating with a starting end of the turbine scroll passage, an exhaust gas outlet passage opening in the direction of the rotational axis of the turbine blade, and the exhaust gas A waste gate passage is formed which communicates with the introduction passage and the exhaust gas outlet passage,
An exhaust turbo supercharger in which a heat insulating layer made of a heat insulating material having a hardness that can be cut by rotation of the turbine blade is formed in the turbine scroll passage,
The heat insulating layer of the turbine scroll passage is fired from a mixture of ceramic particles and a resin binder, and the resin binder is burned away by firing and the ceramic particles bond to each other to form a porous fired layer. It is layered,
and a heat insulating layer made of the same heat insulating material as the turbine scroll passage is also formed in the exhaust gas introduction passage, the exhaust gas outlet passage, and the waste gate passage.
Exhaust turbo supercharger.

Images