Exhaust-flow-rate control valve, and two-stage supercharging system provided with same

Patent metadata

Field	Value
Publication number	US-10844778-B2
Application number	US-201515549058-A
Country	US
Kind code	B2
Filing date	Mar 30, 2015
Priority date	Mar 30, 2015
Publication date	Nov 24, 2020
Grant date	Nov 24, 2020

Abstract

An exhaust-flow-rate control valve for controlling a flow rate of exhaust gas flowing through an exhaust flow passage includes: a valve rod; a valve body having a flat plate shape and configured to rotate about the valve rod; and a valve housing having a cylindrical shape and defining a part of the exhaust flow passage inside the valve housing. A valve seat surface extending along a direction intersecting with an axial direction of the exhaust flow passage and being configured to make contact with an outer peripheral portion of the valve body in a fully-closed state in which an opening degree of the valve body is zero degree, and a flow passage surface extending along the axial direction of the exhaust flow passage and defining a passage region R through which the exhaust gas passes between the flow passage surface and the outer peripheral portion of the valve body in a valve-open state in which the opening degree of the valve body is greater than zero degree are formed on an inner peripheral surface of the valve housing. The passage region R of exhaust gas increases slowly while the valve body transitions from the fully-closed state to a predetermined valve-open state in which the separation distance between the valve body and the end portion of the flow passage surface is shortest.

First claim

The invention claimed is:

1. An exhaust-flow-rate control valve for controlling a flow rate of exhaust gas flowing through an exhaust flow passage, the exhaust-flow-rate control valve comprising:
a valve rod;
a valve body having a flat plate shape and configured to rotate about the valve rod; and
a valve housing having a cylindrical shape and defining a part of the exhaust flow passage inside the valve housing, the valve housing including:
a valve seat surface being formed on an inner peripheral surface of the valve housing, extending along a direction intersecting with an axial direction of the exhaust flow passage, and being configured to make contact with an outer peripheral portion of the valve body in a fully-closed state in which an opening degree of the valve body is zero degree; and
a flow passage surface being formed on the inner peripheral surface of the valve housing, extending along the axial direction of the exhaust flow passage, and defining a passage region through which the exhaust gas passes between the flow passage surface and the outer peripheral portion of the valve body in a valve-open state in which the opening degree of the valve body is greater than zero degree,

wherein a recessed portion is formed on the outer peripheral portion of the valve body, closer to a seat surface which is to be in contact with the valve seat surface than a center line in a thickness direction of the valve body, the recessed portion being disposed on an area recessed from a virtual shape defined by a virtual line Ia passing through the seat surface of the valve body in the fully-closed state and a virtual line Ib passing through a tip of the valve body disposed away by a shortest distance from the flow passage surface in the fully-closed state and extending in a direction perpendicular to the virtual line Ia, in a cross-sectional view taken in a direction perpendicular to a center axis of the valve rod, and
wherein, provided that H 1 is a shortest distance between the valve body and the flow passage surface when the valve body is in the fully-closed state,
wherein a relationship 0<H 1 <d is satisfied, where d is a depth of the recessed portion.

2. The exhaust-flow-rate control valve according to claim 1 ,
wherein the recessed portion has an R shape formed on the outer peripheral portion.

3. The exhaust-flow-rate control valve according to claim 1 ,
wherein the recessed portion has a flat shape formed on the outer peripheral portion.

4. The exhaust-flow-rate control valve according to claim 1 ,
wherein, provided that, when the valve body transitions from the fully-closed state to the valve-open state, a first side is a side at which the outer peripheral portion of the valve body rotates toward a downstream side of the exhaust flow passage and a second side is a side at which the outer peripheral portion of the valve body rotates toward an upstream side of the exhaust flow passage,
the outer peripheral portion of the valve body disposed on the second side is formed into an R shape at an opposite side to the seat surface across the center line in the thickness direction of the valve body.

5. The exhaust-flow-rate control valve according to claim 1 ,
wherein, in a cross-sectional view in a direction perpendicular to a center axis of the valve rod, the flow passage surface comprises a parallel surface parallel to the axial direction of the exhaust flow passage, to an end portion of the flow passage surface from a predetermined position at which a distance to the valve body is the shortest distance H 1 when the valve body is in the fully-closed state.

6. The exhaust-flow-rate control valve according to claim 1 ,
wherein, in a cross-sectional view in a direction perpendicular to a center axis of the valve rod, the flow passage surface comprises an inclined surface inclined with respect to the axial direction of the exhaust flow passage and extending linearly outward toward an end portion of the flow passage surface from a predetermined position at which a distance to the valve body is the shortest distance H 1 when the valve body is in the fully-closed state.

7. The exhaust-flow-rate control valve according to claim 1 ,
wherein, in a cross-sectional view in a direction perpendicular to a center axis of the valve rod, the flow passage surface comprises a curved surface extending in a curved shape inward toward an end portion of the flow passage surface from a predetermined position at which a distance to the valve body is the shortest distance H 1 when the valve body is in the fully-closed state.

8. The exhaust-flow-rate control valve according to claim 7 ,
wherein the flow passage surface is configured such that the shortest distance H 1 between the valve body and the flow passage surface is maintained to be a constant distance while the valve body transitions from the predetermined position to the toward the end portion for a predetermine distance.

9. The exhaust-flow-rate control valve according to claim 1 ,
wherein, in a cross-sectional view in a direction perpendicular to a center axis of the valve rod, a rotational center of the valve body is eccentric to a center line in a height direction of the valve body.

10. The exhaust-flow-rate control valve according to claim 9 ,
wherein, provided that, when the valve body transitions from the fully-closed state to the valve-open state, a first side is a side at which the outer peripheral portion of the valve body rotates toward a downstream side of the exhaust flow passage and a second side is a side at which the outer peripheral portion of the valve body rotates toward an upstream side of the exhaust flow passage,
a rotational center of the valve body is disposed closer to the first side than the center line in the height direction of the valve body.

11. The exhaust-flow-rate control valve according to claim 1 ,
wherein, provided that, when the valve body transitions from the fully-closed state to the valve-open state, a first side is a side at which the outer peripheral portion of the valve body rotates toward a downstream side of the exhaust flow passage and a second side is a side at which the outer peripheral portion of the valve body rotates toward an upstream side of the exhaust flow passage,
in a cross-sectional view in a direction perpendicular to a center axis of the valve rod, a rotational center of the valve body is disposed closer to a downstream side of the exhaust flow passage than the center line in the thickness direction of the valve body of the first side and closer to an upstream side of the exhaust flow passage than the center line in the thickness direction of the valve body of the second side.

12. A two-stage supercharging system, comprising:
an engine;
an exhaust manifold into which exhaust gas discharged from the engine is introduced;
an exhaust system through which the exhaust gas discharged from the exhaust manifold flows;
a high-pressure stage supercharger having a high-pressure stage turbine configured to be driven by the exhaust gas discharged from the exhaust manifold;
a low-pressure stage supercharger comprising a low-pressure stage turbine which is disposed downstream of the high-pressure stage supercharger in the exhaust system and which is configured to be driven by the exhaust gas discharged from the high-pressure stage supercharger; and
the exhaust-flow-rate control valve according to claim 1 ,
wherein the exhaust system includes a high-pressure side bypass flow passage bypassing the high-pressure stage turbine and connecting the exhaust manifold and a downstream side of the high-pressure stage turbine, and
wherein the exhaust-flow-rate control valve is config

Assignees

• Mitsubishi Heavy Ind Engine & Turbocharger Ltd

Inventors

• An Byeongil
• Suzuki Hiroshi

Classifications

• F02B37/013

  with exhaust-driven pumps arranged in series · CPC title

• F16K1/222

  Shaping of the valve member · CPC title

• F02B37/004

  with exhaust drives arranged in series · CPC title

• F02D9/1015

  Details of the edge of the flap, e.g. for lowering flow noise or improving flow sealing in closed flap position · CPC title

• Y02T10/12

  Improving ICE efficiencies · CPC title