JPH0435534Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an exhaust bypass device for a turbocharger of an internal combustion engine.

[Prior Art] A turbocharger for a multi-cylinder internal combustion engine is known in which the inside of the turbine-side housing is divided into two parallel scroll passages. This is a so-called twin-entry turbocharger, which aims to make effective use of the pressure waves in the engine's exhaust gas. That is, the cylinder group is divided into two so that pressure waves are not canceled out, and the exhaust gas from each cylinder group is guided to the respective divided scroll passages. In order to control the upper limit of boost pressure, turbochargers require a valve device (so-called wastegate valve) that bypasses exhaust gas when boost pressure exceeds a predetermined value, but in this twin entry type, there are two flow paths. Therefore, it is necessary to devise ways to control the bypass from each scroll passage. Therefore, in 1988,
No. 88018 and Japanese Utility Model Application No. 56-154532 disclose a system in which a bypass passage for opening each scroll passage is provided in the turbine housing, and the bypass passage is opened and closed by a bypass control valve located in the housing. is suggesting.

[Problem that the invention attempts to solve]

However, in this prior art, each scroll passage is opened and closed by a common valve body. Therefore, if the distance between the bypass passages is wide, the radius of the valve body becomes large, and there is a problem that the size of the turbine housing that houses the valve body becomes large. When the scroll passage is arranged in a direction different from the turbine outlet direction as in the prior art, the interval between the bypass passages can be reduced, so that the two bypass passages can be opened and closed using a relatively small diameter valve body. However, if a structure is adopted in which the bypass passage opens in the same direction as the turbine outlet, the gap between the two bypass passages cannot be made small because the bypass passage to one scroll passage must bypass the other scroll passage. If one valve body were to be used, its diameter would be large.

In order to reduce the size of the valve body, the idea is to open and close each bypass passage with a dedicated small-diameter valve body, and connect the two valve bodies to each other with an arm, which in turn connects to a common boost pressure actuator. It will be done. However, in this case, the arm connecting both valve bodies becomes long due to the distance between the scroll passages, and its rigidity is insufficient, resulting in deformation of the arm due to thermal strain, which causes the valve body to move against the valve seat. Seating becomes uncomfortable and the sealing performance of the valve device is adversely affected.

[Means for solving problems]

According to this idea, in order to solve the above problem,
Two scroll passages are provided in the turbine housing of the turbocharger in parallel so as to open to a common turbine wheel, and an independent bypass passage with one end open to the scroll passage is formed in the housing, and the other end of each bypass passage is connected to the turbine wheel. Separate valve bodies that open and close with respect to the exhaust pipe downstream of the housing are provided on a common plate-shaped arm, and the rotation axis of the arm extends in a direction parallel to the direction in which the separate valve bodies are arranged, The actuator is connected to a supercharging pressure-responsive actuator, and the actuator rotates the arm around the axis of the rotational support shaft by applying a rotational motion to the rotational support shaft, and opens and closes an independent bypass passage by using each valve body. , and on the arm, a first reinforcing rib extending outward beyond the shaft of the valve body in a direction parallel to the direction in which the valve bodies are lined up, and a shaft of the valve body extending in a direction perpendicular to the first rib. A second reinforcing rib is formed in the middle of the valve body and extends to the vicinity of the support shaft, and a clearance is formed between the opposing circumferential surfaces of the valve body shaft and the arm and between the opposing planes of the valve body head and the arm. A turbocharger exhaust bypass device is provided.

[Function] The actuator responds to the boost pressure and rotates the arm when the boost pressure exceeds a predetermined value. Therefore, each valve body provided on the arm opens a corresponding bypass passage. When the boost pressure is below a predetermined value, each valve body closes the corresponding bypass passage. During this closing, the high temperature of the exhaust gas acts on the arm, but since the arm is reinforced by the first and second reinforcing ribs, no thermal distortion occurs in the arm, and in addition, the shaft of the valve body Some looseness is allowed due to the clearance formed between the opposing circumferential surfaces of the part and the arm and between the opposing planes of the valve body head and the arm, and the valve body sits well on the valve seat and is sufficient. It is possible to ensure good sealing performance.

〔Example〕

In FIG. 4, 10 indicates the main body of a six-cylinder internal combustion engine. Reference numeral 12 denotes an intake manifold, which is connected to an air flow meter (not shown) and an air cleaner via a throttle body 14 and intake pipes 16 and 18. A throttle valve 22 is located within the throttle body 14. Exhaust manifold is 24
Two such ports A and 24B are provided, and are connected to the exhaust ports of the first to second cylinders and the fourth to sixth cylinders, respectively. This cylinder division means that the firing order is #1-#5-#3-#6-#2-
Since it is #4, it is divided into groups so that ignition occurs at random between the two groups, thereby preventing exhaust interference and making effective use of pressure waves.

A turbocharger 26 includes a turbine housing 28 and a compressor housing 30. The compressor housing 30 includes an inlet portion 30A that opens at the center of the compressor (not shown) and an outlet portion 30B in the direction of the compressor cutting line, and the inlet portion 30A is connected to the intake pipe 18.
Air cleaner receives air from air flow meter. The outlet portion 30B is connected to the intake pipe 16 and functions to introduce supercharging air into the engine via the throttle valve 22 and the intake manifold 12.

The turbine housing 28 also has a scroll shape, and has turbine wheels 31 (fifth and sixth wheels) inside.
), and this turbine has a rotating shaft 32 mounted on an impeller (not shown) inside the compressor housing 30.
connected by. The scroll-like passage within the turbine housing 28 is divided by a partition 34 into two parallel passages 40A and 40B (fourth and sixth passages).
), thereby creating two side-by-side exhaust gas inlets 42.
A, 42B are formed (Fig. 6), and each entrance 4
2A, 42B are connected to exhaust manifolds 24A, 24B. The housing 28 also has a cylindrical outlet portion 44 extending in the axial direction of the turbine, which is connected to an exhaust pipe 46 .

Bypass passage 50 in turbine housing 28
A and 50B are formed independently (4th and 6th
figure). One end of these bypass passages 50A, 50B opens into the respective scroll passages 40A, 40B near the inlet portions 42A, 42B. The bypass passages 50A, 50B extend within the housing 28 in a direction parallel to the rotating shaft 32, and their ends on the side away from the scroll passages 40A, 40B are connected to the outlet portion 44 of the turbine housing 28 at the inner bottom surface 44A. It's open. This inner bottom surface 44A
extends in a direction perpendicular to the turbine shaft 32.

Reference numeral 60 denotes a bypass control valve constituting a wastegate valve, which is of a swing type and can be moved like a door by means of a support shaft 64. The support shaft 64 is supported by a housing bearing portion 66 . Support shaft 6
An arm 68 is provided at one end of 4. It is connected to diaphragm 721 of diaphragm actuator 72 by link 70 (FIG. 4).
Diaphragm 721 is connected to boost pressure extraction port 76 via pressure guiding pipe 74 . Since the diaphragm actuator 72 is provided in the compressor housing 30 on the low temperature side, it is isolated from the turbine housing 28, which is at a high temperature.
Therefore, heat-sensitive parts such as the diaphragm 721 can be protected, and operational reliability can be improved.

According to the present invention, the bypass control valve 60 includes two valve bodies 82A and 82B (FIGS. 1 and 5), and a bypass passage 50 that opens to the bottom surface 44A of the outlet portion 44.
Valve seat surfaces 83A, 83B as ends of A, 50B
(Fig. 6). Valve body 82A,
82B is attached to a common plate-shaped arm 84. The arm 84 consists of a plate portion 86 to which the valve bodies 82A and 82B are attached, and a cylindrical portion 88.
8 is fitted with a support shaft 64 (FIG. 1). Arm 8
The rotation support shaft 64 of No. 4 extends in a direction parallel to the direction in which the valve bodies 82A and 82B are lined up;
4 to each valve body 82A, 82B is the same, and the rotational momentum of the rotational support shaft 64 is equal to each valve body 82A, 82B.
82B, the reinforcing effect by the ribs described below, and the arm 84 and valve body 82, which will also be described later.
The clearance between the facing surfaces formed between A and 82B also has a synergistic effect of absorbing backlash, so that the valve body 8
This can be achieved by obtaining the correct seating posture of 2A and 82B. The cylindrical portion 88 is an incision 88A.
(FIG. 2), and after fitting the support shaft 64 into the cylindrical portion 88, the arm 84 and the support shaft 64 are integrally connected to each other by welding at the cutout 88A. As shown in FIGS. 2 and 3, the valve bodies 82A and 82B are
It has a shaft portion 90 that tapers in diameter in stages and a head portion, and the shaft portion 90 is formed in the hole 8 of the plate portion 86 of the arm 84.
8B, and the plate portion 86 of the arm 84 is inserted into the shaft portion 9.
It is brought into contact with the joint end surfaces of the first and second stages of 0. On the other hand, the heads of the valve bodies 82A and 82B are fitted with washers 91 in grooves 90A at the tips of the shaft parts 90 that protrude from the plate part 86.
It consists of attaching it and fixing it by caulking like 90B. A clearance C ₁ between the opposing circumferential surfaces of the shaft portion 90 and the hole 88B, and between the opposing planes of the washer 91 of the valve body head and the plate portion 86 of the arm 84, respectively.
C ₂ is formed, and their clearances C ₁ , C ₂
This gives some backlash, which allows the valve bodies 82A and 82B to freely rotate, albeit slightly.
The valve is designed to open and close smoothly without causing valve sticking.

Furthermore, first and second reinforcing ribs 96A and 96B are integrally formed on the bottom end and center of the plate portion 86 of the arm 84. The first reinforcing rib 96A extends outward beyond the shaft portion 90 of the valve body in a direction parallel to the direction in which the valve bodies 82A and 82B are lined up, and the second reinforcing rib 96B extends outward from the first reinforcing rib 96A. It extends in the orthogonal direction between the shaft portions 90 of the valve bodies 82A and 82B to the vicinity of the support shaft 64. This reinforcing rib 96
A, 96B reinforces the plate portion 86 against thermal distortion even if it is thin, and allows the weight gate valve to close the valve body 8 when closed.
2A and 82B are seated on the valve seats 83A and 83B in the correct posture, so that the desired sealing action can be obtained.

Cylinder groups #1, #2, #3 and #4, #5 connected to exhaust manifolds 24A, 24B,
Exhaust gas from #6 enters the scroll passage entrance 42
A, 42B to the respective scroll passages 40A, 4
0B (Fig. 4), enter the turbine housing 28
It acts on the turbine inside and rotates it. Exhaust gas is released from the outlet hole 44. The rotation of the turbine rotates the compressor within the compressor housing 30, and supercharging is performed. Below a predetermined boost pressure, the link 70 is located on the left side of the figure, and this is the valve body 82 of the swing type bypass control valve 60.
The support shaft 64 is rotated so as to press the valves A and 82B against the respective valve seat surfaces 83A and 83B. Therefore,
Bypass passages 50A and 50B are closed.

When the boost pressure exceeds a predetermined value, the diaphragm 7
21 moves to the right in FIG.
A, 82B are rotated, and the valve body is aligned with the valve seat surface 83A, 8.
Move away from 3B. Therefore, part of the exhaust gas is bypassed from the scroll passages 40A, 40B, and is bypassed from the outlet portion 44 to the exhaust pipe 46 via the bypass passages 50A, 50B. As a result, the exhaust gas energy acting on the turbine 31 decreases, the boost pressure drops, and the boost pressure is maintained at a predetermined value.

〔effect〕

During operation, the arm 84 of the bypass control valve 60 is subjected to thermal stress due to the high temperature of the exhaust gas.
Since it is reinforced by 6A and 96B, no thermal deformation occurs. Therefore, there is a clearance between the opposing circumferential surfaces of the shaft portions 90 of the valve bodies 82A and 82B and the arm 84, and between the opposing planes of the valve body head and the arm 84.
C ₁ and C ₂ are provided, and together with some backlash, when the control valve 60 closes, the valve body 8
It is always ensured that the valve seats 2A and 82B are seated in the correct posture with respect to the valve seats 83A and 83B, and a good seal can be achieved when seated. Therefore, it is possible to secure the optimum boost pressure and maintain the desired engine output.

[Brief explanation of drawings]

FIG. 1 is a front view of the main parts of the wastegate valve of the present invention. FIG. 2 is a sectional view taken along the - line in FIG. 1. FIG. 3 is an enlarged view of the connecting portion between the valve body and the arm in FIG. 2. FIG. 4 is an overall view of a turbocharged internal combustion engine equipped with the wastegate valve of the present invention.
FIG. 5 is a side view of the turbine housing of the turbocharger shown in FIG. 4. FIG. 6 is a sectional view taken along the - line in FIG. 5. 26... Turbocharger, 28... Turbine housing, 40A, 40B... Scroll passage, 50A, 50B... Bypass passage, 60...
Bypass control valve, 64... Support shaft, 72... Actuator, 82A, 82B... Valve body, 84... Arm, 96A, 96B... First and second ribs.

Claims (1)

[Scope of utility model registration request] Two scroll passages are provided in the turbine housing of the turbocharger in parallel so as to open to a common turbine wheel, and an independent bypass passage with one end open to the scroll passage is formed in the housing, and the other end of each bypass passage is connected to the turbine wheel. Separate valve bodies that open and close with respect to the exhaust pipe downstream of the housing are provided on a common plate-shaped arm, and the rotation axis of the arm extends in a direction parallel to the direction in which the separate valve bodies are lined up. , is connected to a supercharging pressure responsive actuator, and the actuator rotates the arm around the axis of the rotational support shaft by applying a rotational motion to the rotational support shaft, thereby opening each valve body to create an independent bypass passage. a first reinforcing rib that opens and closes and extends outward beyond the shaft of the valve body in a direction parallel to the direction in which the valve bodies are arranged;
A second reinforcing rib is formed extending in the middle of the shaft of the valve body to the vicinity of the support shaft in a direction perpendicular to the rib, and a second reinforcing rib is formed between the opposing circumferential surfaces of the shaft of the valve body and the arm and the head of the valve body. A turbocharger exhaust bypass device in which a clearance is formed between the opposing planes of the arm and the arm.