JP2768747B2 - Exhaust system for turbocharged engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention derives an exhaust gas from an engine through a supercharger section in which at least two superchargers for which sequential control is performed are arranged outside. The present invention relates to an exhaust device for a supercharged engine.

(Prior Art) A plurality of turbochargers, which are mounted on a vehicle and are configured to supercharge intake air using exhaust gas, in order to improve the efficiency of charging the intake air to more effective droplets. What was done is known. An engine provided with such a plurality of turbochargers includes, for example, a branch exhaust passage forming portion extending from an engine body as disclosed in Japanese Utility Model Laid-Open No. 60-178329 and Japanese Patent Laid-Open No. 60-216030. Is connected to the exhaust gas introduction section of each of the two turbochargers arranged side by side, and passes through each turbocharger from the exhaust gas discharge section side of each turbocharger. The outlet-side exhaust passage forming portion for guiding the exhaust gas to the outside extends.

If two turbochargers juxtaposed to the engine body are to be subjected to sequential control, one of them will operate regardless of its operating state when the engine body operates. Exhaust gas is introduced 1
The secondary supercharger, in which exhaust gas is introduced only when the engine is in a predetermined operating state, for example, a state in which it operates at a relatively high rotational speed, while the other is a secondary supercharger. Therefore, a state in which only the primary supercharger operates and a state in which both the primary supercharger and the secondary supercharger operate according to the operating state of the engine body are taken. In addition, the supercharging of the intake air to the engine body is efficiently performed according to the request of the engine body side.

(Problems to be Solved by the Invention) Generally, an engine provided with a primary side and a secondary side supercharger in which the above-described sequential control is performed is provided with a branch exhaust passage forming portion to separate the primary side and the engine side from the engine body. First and second exhaust passages extending toward the secondary supercharger are formed, and exhaust gas from the engine body passing through the first and second exhaust passages is introduced only into the primary supercharger. And a state in which each of the primary side and the secondary side turbocharger is introduced into the supercharger. In such an engine provided with an exhaust system including first and second exhaust passages extending from the engine body toward a primary side and a secondary side supercharger, exhaust gas discharged from the engine body to the outside If an oxygen sensor (O ₂ sensor) that detects the concentration of oxygen contained in the exhaust gas discharged from the engine body is provided in the exhaust system for the purpose of purifying the exhaust gas, depending on the location of the oxygen sensor, ₂ sensor is not effectively exposed to the exhaust gas, O ₂ problem that early activation of the sensor is not achieved, further, when the secondary-side supercharger is placed into operation by the exhaust gas introduced thereto , O ₂ sensor becomes exhaust resistance that causes a response delay in the secondary turbocharger, so that both the primary and secondary turbochargers operate from the state where only the primary turbocharger operates Switching to a state where A problem that is done it may occur.

In view of the above, according to the present invention, one is a primary-side supercharger into which exhaust gas is introduced regardless of the operation state of the engine body when the engine body is operating, and the other is that the engine body has a predetermined operation. When applied to an engine equipped with two superchargers, which are secondary-side superchargers into which exhaust gas is introduced only when a state is assumed, a primary-side and a secondary-side are used. In arranging the O ₂ sensor in the exhaust system including the first and second exhaust passages extending toward the side turbocharger, the O ₂ sensor is effectively activated early and the secondary side supercharger is effectively arranged. It is an object of the present invention to provide an exhaust system for a supercharged engine that does not cause a response delay in a turbocharger.

(Means for Solving the Problems) In order to achieve the above object, a first mode of an exhaust device for a supercharged engine according to the present invention has an upstream end connected to an engine body and a downstream end connected to an engine body. A first side portion extends toward an exhaust gas inlet of a first supercharger, which is to be brought into operation when the engine body is operated, regardless of its operating state, regardless of its operating state. The exhaust passage and the upstream end are connected to the engine body,
A second exhaust portion, the downstream portion of which extends toward an exhaust gas inlet of a second supercharger, which is to be operated only when the engine body is in a predetermined operating state. A passage, an exhaust communication passage disposed between a downstream portion of the first exhaust passage and a downstream portion of the second exhaust passage, and communicating with the first and second exhaust passages; and O ₂ sensor for detecting the concentration of oxygen contained in exhaust gas discharged from is provided, the O ₂ sensor is disposed in the merging portion which is formed by the downstream portion and the exhaust communication passages of the first exhaust passage It is composed.

According to a second aspect of the exhaust device for a supercharged engine according to the present invention, the first and second exhaust passages and the exhaust communication passage in the first aspect described above are provided inside, and an upstream end face is provided. An exhaust gas introduction portion having a portion connected to a side surface portion of the engine body, and a downstream end surface portion forming an exhaust gas introduction port of the first supercharger; and an exhaust gas introduction port of the second supercharger. and connected to the exhaust manifold to each of the exhaust gas inlet part to form a, and O ₂ sensor for detecting the concentration of oxygen contained in exhaust gas discharged from the engine body is provided, O ₂
A sensor is arranged and arranged at a portion of the exhaust manifold where the distance from the first supercharger is smaller than the distance from the second supercharger.

Further, a third embodiment of the exhaust device for a supercharged engine according to the present invention is the first and second embodiments described above.
In addition to the exhaust passage and the exhaust communication passage, the exhaust gas inlet of the second supercharger is provided with a first exhaust gas inlet and a second exhaust gas inlet having a diameter smaller than that of the first exhaust gas inlet. A partition member partitioned into an exhaust gas inlet, and a first exhaust gas inlet partitioned by the partition member is opened / closed, and the first exhaust gas inlet is opened when the engine body is in a predetermined operating state. A first opening / closing means, and a second
Second opening / closing means for opening and closing the second exhaust gas inlet before the first opening / closing means opens the first exhaust gas inlet. When,
And O ₂ sensor for detecting the concentration of oxygen contained in exhaust gas discharged from the engine body is provided, the O ₂ sensor is first
Are arranged in the exhaust passage.

(Operation) In the first embodiment of the exhaust device for a supercharged engine according to the present invention configured as described above, the merging portion is formed by the first section.
And an exhaust communication path that connects the downstream part of the first exhaust path and the downstream part of the second exhaust path, thereby forming a first supercharger. When the engine body is in the operating state, it is a portion through which exhaust gas discharged from the engine body communicates, and an O ₂ sensor is disposed at the junction.

Also, in a second embodiment of the exhaust device for a supercharged engine according to the present invention, a second exhaust manifold in which first and second exhaust passages and an exhaust communication passage connecting the exhaust passages to each other are provided. portion proximate the first turbocharger than supercharger, i.e., when the engine body is in operation at all times, O ₂ sensor is disposed in the discharge portion of the exhaust gas leading from the engine body.

Further, in the third embodiment of the exhaust device for a supercharged engine according to the present invention, the exhaust device is discharged from the engine main body when the engine main body is in an operating state by being brought close to the first supercharger. An O ₂ sensor is disposed in a first exhaust passage through which exhaust gas passes.

Therefore, in the first, second, and third embodiments of the exhaust system for a supercharged engine according to the present invention, O ₂
When the sensor is in the operating state, the sensor is immediately and surely exposed to the exhaust gas to achieve early activation, and the sensor is located at a position away from the second supercharger. When the engine body is in a predetermined operating state, an exhaust resistance that causes a response delay in the second supercharger into which exhaust gas is introduced from the engine body through the exhaust gas inlet is avoided, and As a result, the transition from the state in which only the first supercharger operates to the state in which both the first and second superchargers operate can be performed smoothly without a shock. Moreover, in the third embodiment of the exhaust passage of the supercharged engine according to the present invention,
Of the first and second exhaust gas inlets obtained by dividing the exhaust gas inlet of the second supercharger, the second exhaust gas inlet having a smaller diameter was opened. At this time, a relatively small amount of exhaust gas is smoothly introduced from the engine main body to the second supercharger through the second exhaust gas introduction port without increasing the exhaust resistance by the O ₂ sensor. Prior to the turbocharger being put into full operation by the exhaust gas through the first exhaust gas inlet, the turbocharger smoothly performs pre-rotation by the exhaust gas through the second exhaust gas inlet. .

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

1 and 2, the engine main body 10 is configured to include three rotor housings 12 and four side housings 13 disposed so as to sandwich each of the three rotor housings 12, The exhaust manifold 8 is attached to one side surface. The side housing 13 located at one end of the engine body 10
Outside, a cooling fan 14 is arranged. A working chamber is formed inside each of the rotor housings 12 in accordance with the rotation of the rotor. Exhaust ports formed in the exhaust manifold 8 are provided in exhaust ports provided in the rotor housing 12 and communicating with the working chambers. The upstream ends of the passages 15, 16 and 17 are connected to each other, and a plurality of intake passages formed in the intake manifold 11 are provided in an intake port provided in the rotor housing 12 and communicating with the working chamber. The downstream ends are connected respectively.

In the exhaust manifold 8, as shown in FIGS. 3A and 3B, flange portions 15 a, 16 a, and 17 a having an exhaust introduction hole 18 are provided at respective upstream ends of the exhaust passages 15 to 17. And the exhaust manifold 8 has a flange 15a,
16a and 17a are brought into contact with the engine body 10 and the flange 15
It is fixed by bolts penetrating a, 16a and 17a.
The thickness of the passage forming portion 25 located between the flange portion 15a and the flange portion 16a is relatively large, and the passage forming portion 26 located between the flange portion 16a and the flange portion 17a is formed. The thickness is relatively small.

Further, a downstream portion of the exhaust passage 16 is branched into branch portions 16A and 16B. A junction 19 is formed by the downstream portion of the exhaust passage 15 and the branch portion 16A, and a downstream portion of the exhaust passage 17 is formed. A merging portion 21 is formed by the side portion and the branch portion 16B, and a downstream portion of the exhaust passage 16 where the branch portions 16A and 16B are formed is a downstream portion of the exhaust passage 15 and a downstream portion of the exhaust passage 17. And an exhaust communication passage for communicating the An opening forming portion 20 is provided at the downstream end of the merging portion 19, and two mounting holes 24 are provided at a projecting portion of the opening forming portion 20 toward the cooling fan 14 side,
A mounting hole is provided at the junction 19 on the cooling fan 14 side.
27 are provided. As shown in FIG. 1, the mounting hole 27 is provided at a downstream portion of the exhaust passage 15 between a downstream portion of the exhaust passage 15 forming the junction 19 and a branch portion 16A of the exhaust passage 16. It has been provided. On the other hand, a rib formed at the downstream end of the junction 21 so as to extend toward the engine body 10 in a direction intersecting the end surface thereof.
An opening forming part 22 sandwiching 29, and an opening forming part 23 that forms an opening whose diameter is larger than the opening formed by the opening forming part 22 are provided, and are located near the opening forming part 23. A mounting hole portion 28 is provided in a portion where the light emitting device is mounted.

As shown in FIG. 1, the exhaust manifold 8 configured as described above includes an opening forming portion 20 provided at a merging portion 19, and opening forming portions 22 and 23 provided at a merging portion 21.
And a rib 29 are respectively formed on a flange portion 31 constituting an exhaust gas introduction portion communicating with a turbine chamber 30A formed on a casing of the primary side supercharger 30 and a casing of a secondary side supercharger 35. Through the turbine chamber 35A, and is fixed by being brought into contact with a flange portion 36 constituting an exhaust gas introduction portion, and an opening formed by the opening forming portion 20 and the flange portion 31.
The exhaust gas inlet 31a formed in the
Further, the opening having a relatively small diameter formed by the opening forming portion 22 and the rib 29 and the exhaust gas inlet 36a having a relatively small diameter formed in the flange portion 36 are communicated with each other, The opening having a relatively large diameter formed by the opening forming portion 23 and the rib 29 and the exhaust gas inlet 36b having a relatively large diameter formed in the flange portion 36 communicate with each other. The exhaust gas inlet of the secondary supercharger 35 formed by the flange portion 36 is substantially the same as the exhaust gas inlet 36a and the exhaust gas inlet 36b having a diameter larger than that of the exhaust gas inlet 36a. And divided into The mounting hole 27 provided in the exhaust manifold 8 has a junction 19 provided in the vicinity of the primary-side supercharger 30 and a secondary-side supercharger.
O ₂ sensor for detecting the oxygen concentration of the exhaust gas passing through the junction 19 of the junction 21 provided close to 35
33 are arranged.

On the other hand, a cover 37 that covers the exhaust gas introduction ports 36a and 36b and passes the exhaust gas introduction ports 36a and 36b is provided above the flange section 36 in the turbine chamber 35A, and the exhaust gas introduction port 36a in the flange section 36 is The valve is opened or closed by an exhaust gas leakage valve 38 that is rotatably mounted on and controlled by an actuator, and an exhaust gas introduction port 36b provided in the flange portion 36 has an opening forming portion. Mounting hole 28 provided in 23
The opening and closing state is set by an exhaust cut valve 39 that is rotatably mounted on a shaft supported by the actuator and is operationally controlled by an actuator 40. The actuator 40 is supported by a bracket 45 attached to an attachment 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 30 is
Regardless of the operating state when the engine body 10 operates,
Exhaust gas is introduced into the turbine chamber 30A through an opening formed in the opening forming portion 20 of the exhaust manifold 8 and an exhaust gas inlet 31a formed in the flange portion 31. When the turbine is driven to take an operating state, and the secondary-side supercharger 35 operates when the engine body 10 takes a predetermined operating state, for example, when the rotational speed is equal to or higher than a predetermined value, or when the rotational speed is When the intake air amount is equal to or greater than the predetermined value, but has not reached the predetermined value,
A relatively small amount of exhaust gas for turbine pre-rotation is introduced into the turbine chamber 35A through an opening formed in the opening forming portion 22 of the exhaust manifold 8 and an exhaust gas inlet 36a opened by an exhaust leakage valve 38. After that, the exhaust gas is to be introduced in earnest through the opening formed in the opening forming portion 23 of the exhaust manifold 8 and the exhaust gas inlet 36b opened by the exhaust cut valve 39. The turbine in the turbine chamber 35A is driven to take an operating state. Thus, 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 opened by the exhaust leakage valve 38, the exhaust gas is opened by the exhaust cut valve 39. By causing the exhaust gas to be introduced into the turbine chamber 35A in earnest through the exhaust gas inlet 36b, the shock generated when the secondary supercharger 35 is operated is suppressed.

The compressor chamber 30B containing the blower provided in the primary-side supercharger 30 is provided with an intake passage through an intake inlet 30a.
The compressor chamber 35B, which is connected to the blower 41 and accommodates a blower provided in the secondary supercharger 35, is connected to an intake passage 42 via an intake introduction portion 35a. Each of the intake introduction passages 41 and 42 is connected to an intake passage provided with an air filter and the like. Further, the pressurized intake air sending section 30b provided in the compressor chamber 30B and the pressurized intake air sending section 35b provided in the compressor chamber 35B are connected to a common pressurized intake passage (not shown). The downstream portion of the pressure intake passage is connected to a junction formed by the upstream ends of the branch intake passages provided in the intake manifold 11. The turbine chamber 30A and the compressor chamber 30B of the primary turbocharger 30 are connected to a connection shaft chamber 30 through which a connection shaft connecting the turbine and the blower passes.
C, and a turbine chamber 35A and a compressor chamber 35B of the secondary supercharger 35 are connected to a connection shaft chamber 35C through which a connection shaft connecting the turbine and the blower passes.
Are connected via

The primary-side and secondary-side superchargers 30 and 35 as described above are provided in the turbine chambers 30A and 35A, respectively. Both ends of a connecting exhaust passage forming portion 46 formed separately from the secondary superchargers 30 and 35 are bolted via gaskets 47 and 48, respectively, and connected by the connecting exhaust passage forming portion 46. And are arranged side by side with respect to the engine body 10. The connecting exhaust passage forming portion 46 is formed of a material whose coefficient of thermal expansion is higher than the coefficient of thermal expansion of the exhaust manifold 8, and the thickness of the gasket 47 on the primary side supercharger 30 side is reduced on the secondary side. The thickness is larger than the thickness of the gasket 48 on the supercharger 35 side. Further, an outlet-side exhaust passage forming portion 50 which exhausts the exhaust gas discharged from the turbine chambers 30A and 35A and passes through the connecting exhaust passage forming portion 46 to the outside, has an upstream end 50a having a gasket 49 connected to the connecting exhaust passage forming portion 46. It is connected by bolting through. Outlet side exhaust passage formation part 50
As shown in FIG. 1 and FIG. 2, it extends obliquely downward by a predetermined distance from the connecting exhaust passage forming portion 46 and is bent toward the secondary supercharger 35 side.

In the example of the exhaust device according to the present invention having the above-described configuration, the following advantages are obtained.

(1) The rigidity of the portion of the exhaust manifold 8 including the opening forming portions 22 and 23 is increased by the rib 29 provided between the opening forming portion 22 and the opening forming portion 23 of the exhaust manifold 8, and the exhaust manifold 8 But the opening forming part
Also in the part including 22 and 23, those having sufficient rigidity and hardly causing thermal deformation due to heat of exhaust gas led out from each rotor housing 12 to the exhaust passages 15, 16 and 17 in the engine body 10. It is said. In addition, the exhaust gas mainly led out from each rotor housing 12 of the engine body 10 to the exhaust passages 16 and 17 is pulsated by ribs 29 provided between the opening forming portions 22 and 23. After the flow is alleviated, it acts on the exhaust leak valve 38. Therefore, the durability of the exhaust leak valve 38 is improved by the rib 29 serving as a buffer member against the exhaust pulsating flow.

(2) The actuator 40 is disposed in the exhaust manifold 8 in the vicinity of the cooling fan 14 which is relatively separated from the exhaust cut valve 39. The length is relatively large, and the size of the actuator 40 can be reduced. In addition, the actuator 40 is efficiently cooled by the cooling fan 14 so that the thermal influence of the primary supercharger 30 is reduced. Is hardly affected.

(3) The thickness of the passage forming portion 25 in the exhaust manifold 8 is made relatively large, and
Is relatively small, and the O ₂ sensor 22
From the secondary supercharger 35 in the exhaust manifold 8
Since the confluent portion 19, which is a portion close to the secondary supercharger 30, is disposed in the downstream portion of the exhaust passage 15 which is formed together with the branch portion 16A of the exhaust passage 16, the secondary supercharger 35 The exhaust gas inlets 36a and 36b are closed by an exhaust leak valve 38 and an exhaust cut valve 39 forming opening / closing means for the exhaust gas inlets 36a and 36b.
When the primary supercharger 30 is introduced into the turbine chamber 30A through the exhaust gas inlet 31a of the secondary supercharger 30 and only the primary supercharger 30 is activated, the exhaust gas from the engine body 10 always flows through the junction 19. The exhaust gas is passed into the turbine chamber 30A, and the flow of the exhaust gas to the turbine chamber 30A side is made favorable.Therefore, when the O ₂ sensor 33 is in the operating state of the engine body 10, Immediately and surely, the engine body 10 is exposed to the exhaust gas, and when the engine body 10 is started, its preheating is performed promptly and the engine is brought into a normal operation state at an early stage. This is prevented, and the absorption of exhaust heat by the passage forming section 26 is made relatively small, thereby contributing to exhaust purification. On the other hand, the exhaust gas inlet 36 in the secondary supercharger 35
b is opened by the exhaust cut valve 39 and the engine body 1
The exhaust gas from 0 is introduced into the turbine chamber 30A through the exhaust gas inlet 31a of the primary supercharger 30, and
The primary and secondary superchargers 30 and 3 are introduced into the turbine chamber 35A through an exhaust gas inlet 36b of the secondary supercharger 35.
Even when the exhaust gas flow velocity is increased due to both of the operation states 5 being performed, it is possible to prevent the O ₂ sensor 33 from generating exhaust resistance that causes a response delay in the secondary supercharger 35. As a result, the transition from the state in which only the primary-side supercharger 30 operates to the state in which both the primary-side and secondary-side superchargers 30 and 35 operate smoothly without any shock. . Further, since the O ₂ sensor 33 is prevented from becoming an exhaust resistance that causes a response delay in the secondary-side supercharger 35, the exhaust gas inlet 36a is particularly exhausted by the exhaust leakage valve 38. When closed before the gas inlet 36b, the exhaust gas is smoothly introduced into the turbine chamber 35A of the secondary supercharger 35 through the exhaust gas inlet 36a, whereby the secondary turbocharger Prerotation of 35 is performed smoothly.

(4) Since the connection exhaust passage forming portion 46 is formed separately from each of the primary side and secondary side superchargers 30 and 35, the primary side supercharger 30 A casing provided with a flange portion 31 and an exhaust gas discharge portion 30c forming an exhaust gas introduction portion, and a casing provided with a flange portion 36 and an exhaust gas discharge portion 35c forming an exhaust gas introduction portion of a secondary supercharger 35; Have a remarkable temperature difference, and 1
Even if a thermal expansion difference occurs between the casing of the secondary supercharger 30 and the casing of the secondary supercharger 35, the difference in thermal expansion is caused by the exhaust gas discharge portion of the primary supercharger 30. The connection portion between the connection exhaust passage forming portion 46 and the connecting portion between the connection exhaust passage forming portion 46 and the exhaust gas discharging portion 35c of the secondary supercharger 35 is connected to the connecting exhaust passage forming portion 46. The distortion, deformation, and the like generated in the forming portion 46 are reduced.

(5) The outlet side exhaust passage forming part 50 is a connecting exhaust passage forming part.
By having been formed separately from 46,
The effect of the difference in thermal expansion generated between the casing of the primary-side supercharger 30 and the casing of the secondary-side supercharger 35 is caused by the difference between the outlet-side exhaust passage forming portion 50 and the connecting exhaust passage forming portion 46. The connection portion is also alleviated, and the distortion, deformation, and the like generated in the connection exhaust passage forming portion 46 are further reduced.

(6) Since the outlet-side exhaust passage forming portion 50 extends obliquely downward by a predetermined distance from the connecting exhaust passage forming portion 46 and is bent toward the secondary supercharger 35, The overall size of the intake system is reduced, and the primary supercharger 30, which tends to become hot, is prevented from being affected by the heat of the exhaust gas through the outlet-side exhaust passage forming portion 50.
The lower-side supercharger 30 avoids a decrease in intake air charging efficiency.

(7) The primary supercharger 30 or both the primary and secondary superchargers 30 and 35 are determined based on the coefficient of thermal expansion of the exhaust manifold 8 which directly receives the high-temperature exhaust gas from the engine body 10. Since the coefficient of thermal expansion of the connecting exhaust passage forming portion 46 that receives the exhaust gas whose temperature has been lowered through the passage is larger, the thermal expansion of the exhaust manifold 8 and the thermal expansion of the connecting exhaust passage forming portion 46 are reduced. Exhaust manifold 8
The primary and secondary turbochargers 30 and 35 connected to both the exhaust manifold forming section 46 and the exhaust manifold forming section 46 respectively have an exhaust manifold 8.
In addition, the distortion generated due to the thermal expansion of each of the connecting exhaust passage forming portions 46 is reduced.

(8) The thickness of the gasket 47 interposed between the exhaust gas discharging portion 30c of the primary supercharger 30 and the connecting exhaust passage forming portion 46 is changed to the exhaust gas discharging portion 35c of the secondary supercharger 35. The thickness of the gasket 48 interposed between the gasket 48 and the connecting exhaust passage forming portion 46 is larger than the thickness of the gasket 48.
The heat influence from the primary-side supercharger 30 absorbed by the primary-side supercharger 30 is increased, and the primary-side supercharger 30 and the secondary-side supercharger 35 that are exerted on the connection exhaust passage forming portion 46 Is small, and the distortion and deformation generated in the connection exhaust passage forming portion 46 are reduced.

In the above-described example, the actuator 40 is supported by the bracket 45 attached to the protruding portion of the exhaust manifold 8 on the cooling fan 14 side. A part of the casing may be a projecting portion toward the cooling fan 14 side, and a configuration may be adopted in which the actuator 40 is supported by a bracket 45 attached to the projecting portion.
A position close to the secondary-side supercharger 35 where the thermal influence of the primary-side supercharger 30 is reduced may be adopted.

(Effects of the Invention) As is clear from the above description, in the exhaust device for a supercharged engine according to the present invention, when one of the engine bodies is operated, the exhaust gas is introduced regardless of the operating state. Two superchargers, the other being a first supercharger and the other being a second supercharger into which exhaust gas is introduced only when the engine body is in a predetermined operating state And a downstream portion extending toward an exhaust gas inlet of the first supercharger in a first exhaust passage having an upstream end connected to the engine main body, provided in the engine main body; An exhaust communication passage connects the end of the second exhaust passage connected to the downstream portion extending toward the exhaust gas inlet of the second supercharger in the second exhaust passage. The second supercharger is placed in communication with the second exhaust passage, and is brought closer to the first supercharger than the second supercharger. An O ₂ sensor is disposed in a downstream portion of the first exhaust passage through which exhaust gas from the main body is passed. Thereby, the O ₂ sensor
When the engine body is in the operating state, it is immediately and reliably exposed to the exhaust gas from the engine body to achieve early activation, and is arranged at a position away from the second supercharger, When the engine main body is in a predetermined operating state, it is possible to avoid a situation in which the second supercharger into which the exhaust gas is introduced from the engine main body through the exhaust gas introduction port causes an exhaust resistance that causes a response delay. as a result,
The transition from the state in which only the first supercharger operates to the state in which both the first and second superchargers operate can be performed smoothly without a shock.

[Brief description of the drawings]

1 and 2 are a schematic plan view and a side view showing an example of an exhaust device of a supercharged engine according to the present invention together with a main part of a rotary piston engine to which the exhaust device is applied.
Figures A and B are a side view and a front view of the exhaust manifold. In the figure, 8 is an exhaust manifold, 10 is an engine body, 15 to
17 is an exhaust passage, 29 is a rib, 22 and 23 are opening forming portions, 30 is a primary supercharger, 31 and 36 are flange portions, 35 is a secondary supercharger, 38 is an exhaust leakage valve, 39 is It is an exhaust cut valve.

Continuation of the front page (56) References JP-A-1-310136 (JP, A) JP-A-3-31519 (JP, A) JP-A-60-50214 (JP, A) JP-A-61-96138 (JP) , A) Fully open sho 60-178329 (JP, U) Fully open sho 60-3540 (JP, U) Fully open sho 62-167844 (JP, U) Really open sho 61-6652 (JP, U) (58) Field surveyed (Int. Cl. ⁶ , DB name) F02B 33/00-39/16

Claims (3)

(57) [Claims] An upstream end is connected to an engine body, and a downstream portion is placed in an operating state by introducing exhaust gas during the operation of the engine body, regardless of its operating state. A first exhaust passage extending toward an exhaust gas inlet of the turbocharger, and an upstream end connected to the engine body;
A second exhaust passage extending downstream toward an exhaust gas inlet of a second supercharger in which exhaust gas is introduced and is operated only when the engine body is in a predetermined operation state; An exhaust communication passage disposed between a downstream portion of the first exhaust passage and a downstream portion of the second exhaust passage, and communicating the first and second exhaust passages; An oxygen sensor disposed at a junction formed by the downstream portion of the exhaust passage and the exhaust communication passage, and detecting an oxygen concentration contained in exhaust gas discharged from the engine body. Exhaust system for turbocharged engine. 2. An engine according to claim 1, wherein an upstream end face is connected to a side face of the engine body, and a downstream end face is provided with exhaust gas at the time of operation of the engine body regardless of an operation state thereof. An exhaust gas introduction portion forming an exhaust gas introduction port of the supercharger, and an exhaust gas introduction port of the second supercharger into which the exhaust gas is introduced only when the engine body is in a predetermined operation state. A first exhaust pipe connected to each of the exhaust gas introduction sections and having an upstream end connected to the engine body and a downstream section extending toward an exhaust gas introduction port of the first supercharger; A second exhaust passage having a passage, an upstream end connected to the engine body, and a downstream portion extending toward an exhaust gas inlet of the second supercharger; and a first exhaust passage. Downstream part and second
An exhaust manifold disposed between the first exhaust passage and the second exhaust passage, the exhaust manifold being provided between the downstream portion of the exhaust passage and the second exhaust passage. An oxygen sensor disposed at a portion closer to the first supercharger than the supercharger and detecting an oxygen concentration contained in exhaust gas discharged from the engine body. Exhaust system for engine. 3. An engine according to claim 1, wherein an upstream end is connected to the engine main body, and a downstream portion is operated when exhaust gas is introduced during operation of the engine main body regardless of its operation state. A first exhaust passage extending toward an exhaust gas inlet of the turbocharger, and an upstream end connected to the engine body;
A second exhaust passage extending downstream toward an exhaust gas inlet of a second supercharger in which exhaust gas is introduced and is operated only when the engine body is in a predetermined operation state; An exhaust communication passage disposed between a downstream portion of the first exhaust passage and a downstream portion of the second exhaust passage, and communicating with the first and second exhaust passages; A partition member for partitioning an exhaust gas inlet of the turbocharger into a first exhaust gas inlet and a second exhaust gas inlet having a smaller diameter than the first exhaust gas inlet; First opening / closing means for controlling opening / closing of the first exhaust gas inlet partitioned by a member, and for opening the first exhaust gas inlet when the engine body is in a predetermined operating state; Controlling the opening and closing of the second exhaust gas introduction port partitioned by the partitioning member; Prior to the opening of the first exhaust gas inlet by the opening / closing means,
A second opening / closing means for opening an exhaust gas inlet of the engine, and an oxygen sensor disposed in the first exhaust passage and detecting an oxygen concentration contained in exhaust gas discharged from the engine body. Exhaust system for supercharged engine.