JPH0331519A - Exhaust device for engine equipped with supercharger - Google Patents

Abstract

PURPOSE:To prevent the strain and deformation at an connected exhaust passage formation part by installing the connected exhaust passage formation part for connecting the exhaust gas discharge part of each supercharger and connecting a single outlet side exhaust passage formation part with the connected exhaust passage formation part, in an engine equipped with the primary and secondary side superchargers. CONSTITUTION:In an intake manifold 8 installed on one side surface of an engine, an opened port forming part 20 is formed at the convergence part 19 of an exhaust passage 15 and an exhaust branching part 16A, and opened port forming parts 22 and 23 are formed at the convergence part 21 of an exhaust passage 17 and an exhaust branching part 16B. These opened port forming parts 20, 22, and 23 are attached onto the flange parts 31 and 36 which communicate to the turbine chambers 30A and 35A which are formed on the casings of the primary and secondary side superchargers 30 and 35. Further, each supercharger 30, 35 fixes the exhaust gas dis charge parts 30c and 35c which are installed in the turbine chambers 30A and 35A and opposed each other, at the both edge parts of a connected exhaust passage forma tion part 46 by bolts, and fixes an outlet side exhaust passage formation part 50 at the formation part 46 by bolts.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is directed to guiding exhaust gas from an engine to the outside through a supercharger section comprising at least two superchargers that are sequentially controlled and arranged in parallel. This invention relates to an exhaust system for a supercharged engine.

(Prior art) An engine installed in a vehicle that is equipped with multiple turbo superchargers that use exhaust gas to supercharge intake air in order to more effectively improve intake air filling efficiency. What has been done is known. An engine equipped with such a plurality of turbo superchargers is disclosed in, for example, Japanese Utility Model Application No. 60-178329.
As shown in Japanese Patent Publication No. 60-216030, the downstream side of the branch exhaust passage forming part extending from the engine body is the exhaust gas introduction part of each of two turbo superchargers arranged in parallel. A connecting part is provided that connects the exhaust gas discharge side of each turbo supercharger, and an outlet side exhaust passage is formed from the connecting part to lead the exhaust gas from each turbo supercharger to the outside. It is assumed that the structure is such that the portion extends.

If two turbo superchargers installed in parallel to the engine are subject to sequential control, one of them will be in the operating state when the engine is operating. When the primary supercharger is one into which exhaust gas is introduced regardless, and the other is one in which the engine body operates in a predetermined operating state, for example, at a relatively high rotational speed. Therefore, depending on the operating state of the engine, only the primary supercharger operates, and the primary supercharger and secondary supercharger operate depending on the operating state of the engine. Both of the engines are in a state of operation, so that the engine body is efficiently supercharged with intake air in accordance with requests from the engine body.

(Problems to be Solved by the Invention) The primary and secondary superchargers that perform sequential control as described above house the respective turbines and blowers, and also contain an exhaust gas introduction section and an exhaust gas introduction section. discharge section,
The temperatures of the casings forming the intake air introduction section and the pressurized intake air delivery section will have a significant temperature difference,
The temperature of the casing of the primary supercharger becomes higher than the temperature of the casing of the secondary supercharger. Therefore, by connecting the exhaust gas discharge parts of the primary and secondary superchargers, one
A connecting portion that guides exhaust gas through the next-side and secondary-side superchargers to the outlet-side exhaust passage forming portion is formed integrally with the respective casings of the primary-side and secondary-side superchargers. In this case, a relatively large difference in thermal expansion occurs between the casings of the primary and secondary turbochargers, which causes distortion and deformation in the connecting parts, causing damage to the primary and secondary turbochargers. This will adversely affect exhaust gas emissions from the next turbocharger, or
There is a risk that the structural reliability of the primary and secondary superchargers including the connecting portion may be reduced.

In view of these points, the present invention provides a primary side supercharger where one side is a primary side supercharger into which exhaust gas is introduced when the engine body is in operation regardless of its operating state, and the other side is a primary side supercharger that is used when the engine body is in a predetermined operation state. It is applied to engines equipped with two superchargers, which are considered to be secondary superchargers, into which exhaust gas is introduced only when the engine is in a state of Distortion, deformation, etc. in the connecting part that connects the exhaust gas discharge parts of the primary and secondary turbochargers, respectively, to output the function to the outside through the charger or both the primary and secondary turbochargers. It is an object of the present invention to provide an exhaust system for a supercharged engine that can be used under conditions where the amount of energy is reduced.

(Means for Solving the Problems) In order to achieve the above-mentioned object, an exhaust system for a supercharged engine according to the present invention provides an exhaust system for a supercharged engine on the downstream side of a branch exhaust passage forming part whose upstream end is connected to the engine main body. an exhaust gas introduction portion of a first supercharger, the end portion of which is configured to introduce exhaust gas regardless of its operating state when the engine body is operating;
The second supercharger is connected to each of the exhaust gas introduction portions of the second supercharger into which exhaust gas is introduced only when the engine body is in a predetermined operating state, and the first and second supercharger A connecting exhaust passage forming part formed separately from the engine is connected to the exhaust gas discharge part of the first supercharger and the exhaust gas discharge part of the second supercharger, so that both exhaust gas discharge parts are connected by the connecting exhaust passage forming part, and the upstream end of the outlet side exhaust passage forming part formed separately from the connecting exhaust passage forming part is connected to the connecting exhaust passage forming part to form the outlet side exhaust passage. The exhaust gas is configured such that the exhaust gas discharged from at least one of the first and second superchargers and passed through the connecting exhaust passage forming part is guided to the outside.

(Function) In the exhaust system for a supercharged engine according to the present invention configured as described above, the exhaust gas discharge section of the first supercharger and the exhaust gas discharge section of the second supercharger are provided. The first and second
It is connected to the supercharger by a connecting exhaust passage forming part formed separately, and furthermore, the upstream end of the outlet side exhaust passage forming part formed separately is connected to the connecting exhaust passage forming part. The exhaust gas is discharged from at least one of the first and second superchargers and passes through the connecting exhaust passage forming part,
It is led out to the outside by the outlet side exhaust passage forming part. Therefore, the temperatures of the casings forming the exhaust gas introduction part and the exhaust gas discharge part of each of the first and second superchargers have a significant temperature difference, and the casings of the first supercharger and Even if a difference in thermal expansion occurs between the casing of the second supercharger and the casing of the second supercharger, the difference in thermal expansion occurs between the exhaust gas discharge part and the connecting exhaust passage forming part of the first and second superchargers. Absorbed by the connecting part between the connecting exhaust passage forming part and the upstream end of the outlet side exhaust passage forming part,
Distortion, deformation, etc. occurring in the connecting exhaust passage forming portion can be effectively reduced.

(Example) FIGS. 1 and 2 show an example of an exhaust system for a supercharged engine according to the present invention, together with the main parts of a rotary piston engine to which the exhaust system is applied.

1 and 2, the engine main body 10 includes three rotor housings 12 and three rotor housings 1.
4 side housings 1 placed across each of 2
3, and an exhaust manifold 8 is attached to one side surface. A cooling fan 14 is disposed outside the side housing 13 located at one end of the engine body 10. A working chamber is formed inside each of the rotor housings 12 in accordance with the rotation of the rotor, and an exhaust boat provided in the rotor housing 12 and communicating with the working chamber,
Exhaust passages 15, 16 formed in the exhaust manifold 8
and 17, and the downstream ends of the plurality of intake passages formed in the intake manifold ll are connected to the intake ports provided in the rotor housing 12 and communicating with the working chamber. are connected to each other.

In the exhaust manifold 8, as shown in FIGS. 3A and 3B, at the upstream end of each of the exhaust passages 15 to 17,
Flange portions 15a and 16a in which exhaust gas introduction holes 18 are formed
and 17a are provided, and the exhaust manifold 8 is
Flange portion 15a.

16a and 17a are brought into contact with the engine body 10, and are fixed by bolts passing through the flange portions 15a, 16a, and 17a. And the flange part 15a
The thickness of the passage forming part 25 located between the flange part 16a and the flange part 16a is relatively large, and the thickness of the passage forming part 26 located between the flange part 16a and the flange part 17a is relatively small. It is assumed that

Further, the downstream portion of the exhaust passage 16 has branch portions 16A and 1
6B, a merging part 19 is formed by the downstream part of the exhaust passage 15 and the branch part 16A, and a merging part 21 is formed by the downstream part of the exhaust passage 17 and the branch part 16B. ing. An opening forming part 20 is provided at the downstream end of the merging part 19 , and two mounting holes 24 are provided in the protruding part of the opening forming part 20 toward the cooling fan 14 . A mounting hole portion 27 is provided in a portion on the cooling fan 14 side. On the other hand, at the upstream end of the merging section 21, there is an opening forming section 22 with a rib 29 formed extending toward the engine main body IO side in between, and an opening having a diameter larger than the opening formed by the opening forming section 22. an opening forming section 23 that forms an opening;
is provided, and a mounting hole 28 is provided in a portion located near the opening forming portion 23.

The exhaust manifold 8 configured as described above has a first
As shown in the figure, an opening forming part 20 provided in the merging part 19 and an opening forming part 22 provided in the merging part 21
and 23 and the rib 29 are respectively formed in the flange part 31 forming an exhaust gas introduction part communicating with the turbine chamber 30A formed in the casing of the primary supercharger 30, and the casing of the secondary supercharger 35. It is fixed in contact with a flange portion 36 constituting an exhaust gas introduction portion communicating with the formed turbine chamber 3'5A, and the exhaust gas formed in the opening formed by the opening forming portion 20 and the flange portion 31 is fixed. The introduction port 31a is communicated with the opening forming portion 22.
The opening formed by the rib 29 and the exhaust gas inlet 36a formed in the flange part 36 are communicated with each other, and the opening formed by the open acid part 23 and the rib 29 and the exhaust gas inlet 36a formed in the flange part 36 are communicated with each other. Gas inlet 3
6b are communicated with each other. In addition, exhaust manifold 8
An O2 sensor 33 for detecting the oxygen concentration of the exhaust gas passing through the confluence section 19 is disposed in the attachment hole section 27 provided in the merging section 19 .

On the other hand, a cover 37 is provided above the flange portion 36 in the turbine chamber 35A to cover the exhaust gas inlets 36a and 36b and communicate them.
The exhaust gas inlet 36b provided in the flange portion 36 is opened or closed by an exhaust leak valve 38 which is rotatably attached to the flange portion 36 and turned to the operating side by an actuator. The exhaust cut valve 39 is rotatably attached to a shaft supported by a mounting hole 28 provided in the forming part 23 and is opened or closed by an exhaust cut valve 39 whose operation is controlled by an actuator 40. . The actuator 40 is supported by a bracket 45 attached to a mounting hole 24 provided on the cooling fan 14 side of the exhaust manifold 8 .

The primary side supercharger 30 and the secondary side supercharger 35 are assumed to be sequentially controlled, and the primary side supercharger Ja3
When the engine body 10 is in operation, the exhaust manifold 8 is placed in the turbine chamber 30A regardless of its operating state.
The opening and flange portion 31 formed in the opening forming portion 20 of
Exhaust gas is introduced through the exhaust gas inlet 31a formed in the engine body, thereby driving the turbine in the turbine chamber 30A and putting it into operation. 10 assumes a predetermined operating state, for example, when the rotational speed exceeds a predetermined value, or when the rotational speed has not reached the predetermined value but the intake air amount exceeds the predetermined value, the turbine chamber 35A After a relatively small amount of exhaust gas for turbine pre-rotation is introduced through the opening formed in the opening forming part 22 of the exhaust manifold 8 and the exhaust gas inlet 36a opened by the exhaust leak valve 38, Exhaust gas is fully introduced through the opening formed in the opening forming part 23 of the exhaust manifold 8 and the exhaust gas inlet 36b opened by the exhaust cut valve 39, thereby causing the inside of the turbine chamber 35A to be fully introduced. The turbine is driven and becomes operational. In this way, after a relatively small amount of exhaust gas for turbine pre-rotation is introduced into the turbine chamber 35A through the exhaust gas inlet 36a which is opened by the exhaust leak valve 38, the exhaust gas is opened by the exhaust cut valve 39. Exhaust gas inlet 3'
By fully introducing exhaust gas into the turbine chamber 35A through 6b, the secondary supercharger 35
The shock that occurs when the is activated is suppressed.

A compressor chamber 30B that accommodates a blower provided in the primary supercharger 30 is connected to an intake air introduction passage 41 via an intake air introduction section 30a, and is connected to an intake air introduction passage 41 via an intake air introduction section 30a.
Compressor room 35B that accommodates the blower installed in
is connected to the intake air introduction passage 42 via the intake air introduction section 35a.

The intake air introduction passages 41 and 42 are each connected to an intake passage provided with an air filter and the like.

Further, the pressurized intake air delivery section 30b provided in the compressor chamber 30B and the pressurized intake air delivery section 35b provided in the compressor room 35B are connected to a common pressurized intake passage (not shown), and the A downstream portion of the pressure intake passage is connected to a merging portion formed by the upstream end of each branched intake passage provided in the intake manifold 11 . The turbine chamber 30A and compressor chamber 30B of the primary side supercharger 30 are connected via a connecting shaft chamber 30C through which a connecting shaft connecting the turbine and the blower passes, and the secondary side The turbine chamber 35A and compressor chamber 35B of the supercharger 8!35 are connected via a connecting shaft chamber 35C through which a connecting shaft connecting the turbine and the blower passes.

The primary side and secondary side superchargers 30 and 35 as described above are
Exhaust gas discharge portions 30c and 35c provided in the respective turbine chambers 30A and 35A and facing each other,
A connecting exhaust passage forming part is bolted to both ends of a connecting exhaust passage forming part 46 formed separately from the primary and secondary superchargers 30 and 35 via gaskets 47 and 48, respectively. 46, and are arranged in parallel to the engine body 10. The connecting exhaust passage forming part 46 is formed of a material whose coefficient of thermal expansion is larger than that of the exhaust manifold 8, and the thickness of the gasket 47 of the 30 primary side superchargers is the same as that of the secondary side. supercharging 835
It is said to be larger than the thickness of the side gasket 4 days. Furthermore, an outlet side exhaust passage forming part 50 that guides exhaust gas discharged from the turbine chambers 30A and 35A and passing through the connecting exhaust passage forming part 46 to the outside has an upstream end 50a attached to the connecting exhaust passage forming part 46 and a gasket 49. They are connected by being bolted together. As shown in FIGS. 1 and 2, the outlet side exhaust passage forming part 50 extends obliquely downward by a predetermined distance from the connecting exhaust passage forming part 46, and extends downward from the connecting exhaust passage forming part 46.
It is said that it is bent toward the next supercharger 35 side.

An example of the exhaust system according to the present invention configured as described above provides the following advantages.

(1) Since the connecting exhaust passage forming portion 46 is formed separately from each of the primary and secondary superchargers 30 and 35, the Flange portion 31 forming an exhaust gas introduction portion and exhaust gas discharge portion 3
0c is provided, and the casing in which the flange portion 36 forming the exhaust gas introduction portion of the secondary side supercharger 35 and the exhaust gas discharge portion 35c are provided has a significant temperature difference. Casing of supercharger 30 and 2
Even when a difference in thermal expansion occurs between the casing of the next supercharger 35 and the casing of the next supercharger 35, the difference in thermal expansion occurs between the exhaust gas discharge part 30c of the first supercharger Ia30 and the connecting exhaust passage forming part 46. and the exhaust gas discharge part 35 of the secondary side supercharger 35
c and the connecting exhaust passage forming part 46, and distortion, deformation, etc. occurring in the connecting exhaust passage forming part 46 are reduced.

(2) Since the outlet side exhaust passage forming part 50 is formed separately from the connecting exhaust passage forming part 46, the primary side supercharger 300 casing and the secondary side supercharger 35 are separated. The influence of the thermal expansion difference generated between the outlet side exhaust passage forming part 50 and the connecting exhaust passage forming part 46 is also alleviated by the connection part between the outlet side exhaust passage forming part 50 and the connecting exhaust passage forming part 46, thereby reducing the distortion and deformation that occurs in the connecting exhaust passage forming part 46. etc. will be further reduced.

(3) Since the outlet side exhaust passage forming part 50 extends diagonally downward by a predetermined distance from the connecting exhaust passage forming part 46 and is bent toward the secondary side supercharger 35, In addition to reducing the size of the entire intake system, an outlet side exhaust passage forming section 5 is added to the primary side supercharger 30, which tends to reach high temperatures.
0 is prevented from exerting a thermal influence on the exhaust gas, and a decrease in intake air filling efficiency by the primary side supercharger 30 is avoided.

(4) Passage forming portion 25 in exhaust manifold 8
The thickness of the passage forming portion 26 is made relatively large, and the thickness of the passage forming portion 26 is made relatively small.
By disposing the sensor 33 at the confluence section 19,
Exhaust gas inlet ports 36a and 3 in the secondary supercharger 35
6b is closed by the exhaust leak valve 38 and the exhaust cut valve 39, and most of the exhaust gas from the engine body 10 is introduced into the turbine chamber 30A through the exhaust gas inlet 31a in the primary side supercharger 30. When only the next supercharger 30 is in operation, the exhaust gas turbine chamber 30
The flow to the A side is made good, and as a result, when the engine main body IO is started, the 0□ sensor 33 is quickly preheated and brought into a normal operating state at an early stage. Inconveniences such as deformation of the forming portion 25 are prevented from occurring, and absorption of exhaust heat by the passage forming portion 26 is made relatively small, contributing to exhaust gas purification. On the other hand, the exhaust gas inlet 36b of the secondary supercharger 35 is opened by the exhaust cut valve 39, and the exhaust gas from the engine body 10 passes through the exhaust gas inlet 31a of the primary supercharger 30 into the turbine chamber. 30A and is also introduced into the turbine chamber 35A through the exhaust gas inlet 36b in the secondary side supercharger 35.
When both the next-side and secondary-side superchargers 30 and 35 are activated and the flow rate of exhaust gas is increased, an increase in exhaust resistance due to the 0□ sensor 33 is avoided.

(5) The rib 29 provided between the opening forming part 22 and the opening forming part 23 in the exhaust manifold 8 increases the rigidity of the entire exhaust manifold 8, and the rib 29 causes exhaust pulsation that acts on the exhaust leak valve 38. This serves as a buffer member against the exhaust gas leakage valve 38, thereby improving the durability of the exhaust leakage valve 38.

(6) The actuator 40 is connected to the exhaust manifold 8
Although the actuator 40 is located near the cooling fan 14 and relatively far away from the exhaust cut valve 39, the stroke length of the actuator 40 is made relatively large due to this arrangement. , actuator 4
In addition, the actuator 40 is efficiently cooled by the cooling fan 14 and is less likely to be affected by the heat of the primary supercharger 30.

(7) Based on the thermal expansion coefficient of the exhaust manifold 8 that directly receives high-temperature exhaust gas from the engine body IO, the primary side supercharger 30 or the primary and secondary side superchargers 30 and 35
Since the thermal expansion coefficient of the connecting exhaust passage forming part 46 that receives the exhaust gas whose temperature has been lowered through both of the above is larger, the thermal expansion of the exhaust manifold 8 and the heat of the connecting exhaust passage forming part 46 are larger. The exhaust manifold 8 and the connecting exhaust passage are connected to the primary side and secondary side superchargers 30 and 35, respectively, which have substantially the same expansion and are connected to both the exhaust manifold 8 and the connecting exhaust passage forming part 4G. Distortion caused by thermal expansion of each of the forming portions 46 is reduced.

(8) Gasket 47 interposed between the exhaust gas discharge part 30c of the primary side supercharger 30 and the connecting exhaust passage forming part 46
is larger than the thickness of the gasket 48 interposed between the exhaust gas discharge part 35c of the secondary side supercharger 35 and the connecting exhaust passage forming part 46, so that the gas is absorbed by the gasket 48. The primary side supercharger 3 absorbs the heat influence from the secondary side supercharger 35 by the gasket 47.
The thermal influence from the primary side supercharger 30 and the secondary side supercharger 3 is said to be larger and is exerted on the connecting exhaust passage forming part 46.
5 is made small, and distortion and deformation occurring in the connecting exhaust passage forming portion 46 are reduced.

Note that in the above example, the actuator 40 is supported by a bracket 45 attached to a protrusion toward the cooling fan 14 side of the exhaust manifold 8; A part of the casing is a protrusion toward the cooling fan 14, and the actuator 4 is attached to a bracket 45 attached to the protrusion.
0 may be supported, and furthermore, the actuator 40 takes a position close to the secondary supercharger 35, where the thermal influence of the primary supercharger 30 is small. It may be taken as a thing.

(Effects of the Invention) As is clear from the above description, in the exhaust system for a supercharged engine according to the present invention, exhaust gas is introduced into one side when the engine body is operating, regardless of its operating state. Two superchargers, one of which is a first supercharger that operates in a specified manner, and the other a second supercharger into which exhaust gas is introduced only when the engine body is in a predetermined operating state. In an engine equipped with
The exhaust gas discharge part of the supercharger and the exhaust gas discharge part of the second supercharger are connected by a connecting exhaust passage forming part formed separately from the first and second superchargers, Further, an outlet-side exhaust passage forming part formed separately from the connecting exhaust passage forming part is connected to the connecting exhaust passage forming part, so that the exhaust from at least one of the first and second superchargers passes through the connecting exhaust passage forming part. The exhaust gas is guided to the outside by the outlet side exhaust passage forming part, so that the casing and the second supercharger form an exhaust gas introduction part and an exhaust gas exhaust part in the first supercharger. Even if a difference in thermal expansion occurs between the exhaust gas introduction part and the casing forming the exhaust gas discharge part in the turbocharger, the difference in thermal expansion will cause the exhaust gas discharge part of each of the first and second superchargers to increase. Distortion, deformation, etc. in the connecting exhaust passage forming part is absorbed by the connecting part between the connecting exhaust passage forming part and the connecting exhaust passage forming part, and furthermore, the connecting part between the connecting exhaust passage forming part and the outlet side exhaust passage forming part. A situation in which the exhaust gas emissions from the first and second superchargers are effectively reduced and, therefore, exhaust gas emissions from the first and second superchargers are adversely affected, or a configuration in the first and second superchargers that includes a connecting exhaust passage forming part. This means that the deterioration of the above credibility can be avoided.

[Brief explanation of drawings]

1 and 2 are a schematic plan view and a side view showing an example of the exhaust system for a supercharged engine according to the present invention together with the main parts of a rotary piston engine to which it is applied;
Figures A and B are side and front views of the exhaust manifold. In the figure, 8 is the exhaust manifold, 10 is the engine body, 1
5 to 17 are exhaust passages, a flow section, 30 a primary side supercharger, 3 a turbine chamber, 30c and 35c, 31 and 36 flange parts, 346 a connecting exhaust passage forming part, and 5 a passage forming part. 19 and 21 are joint OA, 35A is exhaust gas discharge part, 5 is secondary side supercharger, O is outlet side exhaust vent

Claims (1)

[Scope of Claims] A first valve having an upstream end connected to the engine main body and a downstream end into which exhaust gas is introduced when the engine main body is in operation, regardless of the operating state of the engine main body.
and an exhaust gas introduction part of a second supercharger into which exhaust gas is introduced only when the engine main body is in a predetermined operating state. a branch exhaust passage forming section formed separately from the first and second superchargers, an exhaust gas discharge section of the first supercharger and an exhaust gas discharge section of the second supercharger; a connecting exhaust passage forming part that is connected to the connecting exhaust passage forming part and connecting both the exhaust gas discharge parts; and the connecting exhaust passage forming part is formed separately from the connecting exhaust passage forming part, and the upstream end is connected to the connecting exhaust passage forming part. , an outlet-side exhaust passage forming part that guides exhaust gas discharged from at least one of the first and second superchargers and passing through the connected exhaust passage forming part to the outside. Engine exhaust system.