JPH05156958A - Exhaust bypass device for turbocharger - Google Patents

Abstract

PURPOSE:To prevent a vibration from occurring in making exhaust gas flow into a bypass passage so smoothly by forming one of the bypass passages derived from the outer circumference of a scroll passage with a small radius of curvature and the other bypass passage with a large radius of curvature, respectively, while bending these passages in the axial direction of a turbine and connecting them to an outlet of a turbine housing. CONSTITUTION:Two scroll passages 3, 4 are arranged in a turbine housing 1 toward a turbine shaft 6, and a size 8 of an outer circumference of the scroll passage 3, nearer to an outlet 7 of the turbine housing 1 out of these two scroll passages 3 and 4, is set down to a smaller one 9 than that of the other side scroll passage 4. In addition, a bypass passage 10 nearer to the outlet 7 is bent toward the shaft 6 at a small radius of curvature, and the other side bypass passage 12 is bent toward the turbine shaft 6 at a large radius of curvature and connected to an outlet 13 of the turbine housing 1. With this constitution, exhaust gas flows into these bypass passages 10, 12 so smoothly by dint of centrifugal force in time of passing through these scroll passages 3 and 4, thus a vibration in the turbine is prevented from occurring.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust bypass device for a turbocharger of an internal combustion engine.

[0002]

2. Description of the Related Art In a turbocharger for a multi-cylinder internal combustion engine, two scroll passages are provided in a turbine housing side by side in the axial direction of the turbine so that exhaust gas of the internal combustion engine is divided into two scroll passages and guided. It has been used conventionally.

[0003]

However, in the conventional turbocharger, the bypass passage for bypassing the exhaust gas when the supercharging pressure becomes equal to or higher than a predetermined value is provided in the axial direction as in Japanese Utility Model Publication No. 3-18664. When it is bent to the outside and connected to the outlet of the turbine housing, and when bypassing from the two scroll passages, the bypass passage near the outlet of the turbine housing is not smoothly connected to the outer peripheral portion of the scroll passage. And the flow rate difference between the two bypass passages is generated.

The present invention overcomes these drawbacks of the prior art,
An object of the present invention is to provide an exhaust bypass device for a turbocharger, in which the size of the turbine housing in the radial direction is reduced and the flow in the scroll passage is not disturbed so that a difference in flow rate between the two bypass passages does not occur.

[0005]

According to an exhaust bypass device for a turbocharger of the present invention, two scroll passages are arranged in a turbine housing of the turbocharger in an axial direction of the turbine, and one of the two scroll passages is connected to the turbine housing. The outer circumference of the scroll passage near the outlet is made smaller than the outer circumference of the other scroll passage, and the bypass passage led from the outer circumference of the scroll passage near the outlet of the turbine housing is bent in the axial direction of the turbine with a small radius of curvature to make the turbine housing The bypass passage connected to the outlet and guided from the outer periphery of the other scroll passage is bent in the axial direction of the turbine with a large radius of curvature and connected to the outlet of the turbine housing.

[0006]

The bypass passage led out from the outer circumferences of the two scroll passages is bent in the axial direction of the turbine and connected to the outlet of the turbine housing. Therefore, the radial dimension of the turbine housing is reduced to bypass the exhaust gas. It can be carried out.

[0007]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of an embodiment of the present invention. A turbine 2 is rotatably provided inside a turbine housing 1 of a turbocharger, and two scrolls are provided on the outer periphery of the turbine 2. The passages 3 and 4 are partitioned by a partition wall 5 and are formed in the turbine housing 1 side by side in the direction of the axis 6 of the turbine.

The scroll passages 3 and 4 are connected to an exhaust manifold of an internal combustion engine (not shown), and the exhaust gas of the internal combustion engine enters the scroll passages 3 and 4 from the exhaust manifold in a tangential direction and acts on the turbine 2. After being rotated, the gas is discharged from the outlet 7 of the turbine housing 1 through a muffler (not shown).

Of the two scroll passages 3 and 4, the scroll passage 3 closer to the outlet 7 of the turbine housing 1
The outer peripheral dimension 8 of is the outer peripheral dimension 9 of the other scroll passage 4.
It has smaller dimensions. The angle α on the front side of the turbine 2 between the partition wall 5 partitioning the two passages and the shaft 6 of the turbine is equal to 90 ° or slightly smaller than 90 °.

The bypass passage 10 is led out from the outer periphery of the scroll passage 3 near the outlet 7 of the turbine housing 1, and the bypass passage 10 is provided in the turbine housing 1.
Is connected to the outlet 11. Further, the bypass passage 12 is led out from the outer circumference of the other scroll passage 4 far from the outlet 7 of the turbine housing 1, and the bypass passage 12 is connected to the outlet 13 of the turbine housing 1.

The bypass passage 10 is bent with a small radius of curvature 14 in the direction of the turbine axis 6 and extends along the turbine axis 6 towards the outlet 11, while the other bypass passage 12 extends outside the bypass passage 10. It is bent in the direction of the turbine axis 6 with a radius of curvature 15 and extends along the turbine axis 6 towards the outlet 12. And exit 11,1
A bypass control valve 16 is provided at 3.

Next, the operation will be described.

Exhaust gas from the internal combustion engine enters the scroll passages 3 and 4 from the exhaust manifold tangentially, acts on the turbine 2, rotates the turbine 2, and then passes through a muffler (not shown) from an outlet 7 of the turbine housing 1. Is discharged. When the boost pressure is less than the specified value, bypass control valve 1
Although the outlets 11 and 13 are closed by 6, the bypass control valve 16 is opened against the force of a spring (not shown) when the supercharging pressure exceeds a predetermined value. For this reason, a part of the exhaust gas in the scroll passages 3 and 4 is partially bypassed by the bypass passage 1.
After passing through 0 and 12, the fuel is bypassed to the outlets 11 and 13, and the rotation of the turbine 2 is reduced so that the supercharging pressure becomes equal to or lower than a predetermined value.

[0015]

According to the present invention, since the bypass passage is led out from the outer periphery of the scroll passage, the exhaust gas smoothly flows into the bypass passage due to the centrifugal force when passing through the scroll passage. Then, of the two scroll passages, the outer circumference of the scroll passage near the outlet of the turbine housing is made smaller than the outer circumference of the other scroll passage, and the bypass passage is bent in the axial direction of the turbine with a small radius of curvature.
Since the other scroll passage has a larger outer peripheral size than this and the bypass passage is bent in the axial direction of the turbine with a large radius of curvature, the exhaust gas flowing from the other scroll passage to the bypass passage has a large centrifugal force. It is possible to cancel the increased flow resistance due to the increased length of the passage and equalize the flow rates of the two bypass passages. Further, since the connecting portion between the bypass passage and the scroll passage is located on the outer peripheral portion of the scroll passage farthest from the turbine, the flow in the two scroll passages is less disturbed and the turbine does not vibrate.

Further, since the bypass passage is bent in the axial direction of the turbine and connected to the outlet of the turbine housing, the radial dimension of the turbine housing can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention.

[Explanation of symbols]

 1 Turbine Housing 2 Turbine 3 Scroll Passage 4 Scroll Passage 6 Turbine Shaft 7 Outlet 8 Outer Diameter 9 Outer Diameter 10 Bypass Passage 11 Outlet 12 Bypass Passage 13 Outlet 14 Small Curvature Radius 15 Large Curvature Radius

Continued Front Page (72) Inventor Nobuhiro Kondo 3-15-15 Toyosu, Koto-ku, Tokyo Ishikawajima Harima Heavy Industries Co., Ltd. Toni Technical Center

Claims (1)

[Claims] 1. Two scroll passages are arranged in a turbine housing of a turbocharger in an axial direction of the turbine,
Of the two scroll passages, the outer circumference of the scroll passage near the outlet of the turbine housing is smaller than the outer circumference of the other scroll passage, and the bypass passage led from the outer circumference of the scroll passage near the outlet of the turbine housing has a small radius of curvature. Is connected to the outlet of the turbine housing by bending in the axial direction of the turbine, and the bypass passage led from the outer periphery of the other scroll passage is bent in the axial direction of the turbine with a large radius of curvature and connected to the outlet of the turbine housing. Exhaust bypass device for turbocharger.