JPH11148339A - Exhaust system of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the early activation of a catalyst, in its turn the improvement of exhaust emission cleaning performance compatible with securing of operability. SOLUTION: The exhaust passage 2 for the right bank of a V type internal combustion engine 1 is connected to a junction passage 4 with a catalyst A intervening. The junction passage 4 jointed to an exhaust passage 3 for a left bank is connected to an exhaust turbo supercharger 5. A catalyst C intervenes in the exhaust passage 6 on the outlet side of the exhaust turbo supercharge 5. In addition, a bypass passage 7, branches from the exhaust passage 3 for the left bank and is connected to the exhaust passage 6 bypassing the exhaust turbo supercharger 5 and in which a catalyst B intervenes, is provided. The exhaust passage 3 for the left bank is provided with a switch valve 3A, and the bypass passage 7 is provided with a switch valve 7A. Before the activation of the catalyst C, the switch valve 3A is closed and the switch valve 7A is opened, and after the activation of the catalyst C, the switch valve 3A is opened, and the switch valve 7a is closed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an exhaust system for an internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, as an exhaust system for an internal combustion engine, for example, there is one disclosed in Japanese Patent Application Laid-Open No. Hei 5-321463. In this case, when the engine is cold, the exhaust gas is directly introduced into the auxiliary catalyst by bypassing a turbo having a relatively large heat capacity, so that the auxiliary catalyst can be quickly activated.

[0003] Further, there is an engine disclosed in Japanese Utility Model Laid-Open Publication No. 1-173423. In this V-type internal combustion engine with a turbocharger, when a turbocharger is not charged, the turbo is bypassed and exhaust from both banks is discharged. The catalyst is introduced.

[0004]

However, in the system disclosed in Japanese Patent Application Laid-Open No. Hei 5-321643, the exhaust gas bypasses the turbo when the engine is cold. When the exhaust gas is switched to the turbo after the catalyst is activated, etc., there is a risk that a turbo lag may occur and the exhaust gas is cooled by the turbo. There is a risk that purification will not be possible.

[0005] Also, in the case of Japanese Utility Model Laid-Open No. 1-173423, similarly, the turbo is completely bypassed.
There is a fear that a turbo lag may occur, and the exhaust gas may be cooled by the turbo. Therefore, there is a fear that the exhaust gas may not be sufficiently purified by the catalyst. The present invention has been made in view of such a conventional situation, and enables early activation of an exhaust treatment member (for example, a catalyst or the like). By avoiding the fear that the exhaust gas purification performance will be reduced by cooling by the turbo, early activation of exhaust treatment members, improvement of exhaust treatment performance and securing of operability are both at a high level. An object of the present invention is to provide an exhaust system for an internal combustion engine that can achieve both.

[0006]

According to the first aspect of the present invention, a plurality of cylinders are provided, and exhaust from at least one specific cylinder among the plurality of cylinders is merged via a specific cylinder exhaust passage. After being guided to the passage, the exhaust gas is guided to the exhaust supercharger, and the exhaust gas from the non-specific cylinder other than the specific cylinder is guided to the merged passage through the non-specific cylinder exhaust passage, and then guided to the exhaust supercharger. An exhaust system for an internal combustion engine that guides exhaust gas that has passed through an exhaust supercharger to an exhaust processing member via an exhaust passage after passing through the exhaust supercharger, wherein the exhaust system branches off from the non-specific cylinder exhaust passage, A bypass passage that bypasses a supercharger and is connected to the exhaust passage after passing through the exhaust supercharger on the exhaust upstream side of the exhaust processing member, and for a non-specific cylinder on a downstream side of the exhaust passage from a branch portion of the bypass passage. Provided in the exhaust passage, A first control valve for controlling the flow of exhaust gas from the non-specific cylinder exhaust passage into the merged passage; and an inflow of exhaust gas from the bypass passage into the exhaust passage after passing through the exhaust supercharger, provided in the bypass passage. And a second control valve for controlling the pressure.

[0007] With this configuration, the exhaust gas from the specific cylinder is always introduced into the exhaust turbocharger while the exhaust gas from the non-specific cylinder is controlled by the first control as required. By controlling the valve and the second control valve, it is possible to introduce the exhaust gas into the exhaust gas treating member through the bypass passage without introducing the gas into the exhaust gas turbocharger or into the exhaust gas treating member without introducing the gas into the exhaust gas turbocharger. Become.

That is, for example, when the exhaust processing member is not activated, the exhaust from the non-specific cylinder is passed through the bypass passage (without passing through the exhaust supercharger).
This allows the gas to flow into the exhaust processing member. Therefore, since the heat of the exhaust gas from the non-specific cylinder is not taken away by the exhaust supercharger, the exhaust gas can flow into the exhaust gas treatment member without lowering the exhaust gas temperature so much. Can be promoted at an early stage, so that the exhaust treatment (for example, purification) performance can be improved.

On the other hand, since the exhaust from the specific cylinder is always made to flow into the exhaust supercharger, even if the exhaust from the non-specific cylinder does not flow into the exhaust supercharger as described above. During this time, the exhaust supercharger can be brought into a predetermined supercharged state and the temperature of the exhaust supercharger can be raised, so that, for example, all the exhaust gas is caused to flow into the exhaust supercharger after the activation of the exhaust processing member. Even when the exhaust flow path is switched, there is a concern that the turbo lag (delay in boost pressure rise) will increase as in the past, and that the exhaust gas will be cooled by the exhaust supercharger and the exhaust treatment performance will decrease. Can be reliably avoided.

That is, according to the present invention, it is possible to achieve both the early activation of the exhaust treatment member, that is, the improvement of the exhaust treatment performance and the assurance of operability at a high level, with a simple structure. A possible exhaust system can be provided. In the invention according to claim 2, before the activation of the exhaust processing member, the first control valve is controlled to stop the flow of exhaust gas from the non-specific cylinder exhaust passage to the merge passage, and A pre-activation control means for controlling a second control valve to allow exhaust gas to flow into the exhaust passage after passing through the exhaust supercharger via the bypass passage, and after activation of the exhaust treatment member,
The first control valve is controlled to allow exhaust gas to flow into the merge passage through the non-specific cylinder exhaust passage, and the second control valve is controlled to allow the exhaust supercharger to pass from the bypass passage. And a post-activation control means for stopping the flow of exhaust gas into the rear exhaust passage.

[0011] With this configuration, when the exhaust processing member is not activated by the pre-activation control means, the exhaust gas from the non-specific cylinder is passed through the bypass passage (passing through the exhaust supercharger). Instead of flowing into the exhaust treatment member. Therefore, since the heat of the exhaust gas from the non-specific cylinder is not taken away by the exhaust supercharger, the exhaust gas can flow into the exhaust gas treatment member without lowering the exhaust gas temperature so much. Early activation can be promoted, so that the exhaust treatment performance can be improved.

On the other hand, even when the pre-activation control means is performing control, the exhaust gas from the specific cylinder is always allowed to flow into the exhaust supercharger. When the exhaust gas treatment member is activated, the post-activation control means exhaustly supercharges exhaust gas from a non-specific cylinder. Even if the exhaust flow path is switched to ensure the power performance, the turbo lag (delay in boost pressure rise) as in the past may increase, and the exhaust gas is cooled down by the exhaust turbocharger. It is possible to reliably avoid the possibility that the processing performance is reduced.

[0013] That is, according to the present invention, it is possible to achieve both early activation of the exhaust treatment member, that is, improvement of the exhaust treatment performance and securing of operability at a high level, with a simple structure. It becomes possible. In the invention according to claim 3, even before the exhaust processing member is activated, when there is a driver's request, the control by the pre-activation control means is stopped to control the first control valve. The exhaust gas flows into the merging passage through the non-specific cylinder exhaust passage,
Driver request fulfillment control means for controlling the second control valve to stop the flow of exhaust gas from the bypass passage into the exhaust passage after passing through the exhaust supercharger is included.

With this configuration, even before the exhaust processing member is activated, all the exhaust gas (including exhaust gas from a non-specific cylinder) flows into the exhaust supercharger when the driver requests it. Therefore, it is possible to secure (prioritize) the power performance according to the driver's request. In the invention described in claim 4, an exhaust processing member is interposed in the exhaust passage for the specific cylinder.

According to the fifth aspect of the present invention, an exhaust treatment member is interposed in the merging passage. In the invention described in claim 6, an exhaust treatment member is interposed in the bypass passage. In the invention described in claim 7, the exhaust processing member is interposed in the non-specific cylinder exhaust passage upstream of the branch from the bypass passage.

According to the present invention, in addition to the exhaust processing member into which exhaust gas flows through the exhaust passage after passing through the exhaust supercharger, a combustion chamber (cylinder) of the internal combustion engine is provided. (2) Since the exhaust processing member is provided at a position closer to (i.e., at a position having a high exhaust temperature), the exhaust processing member which can be activated early after the start-up further improves the exhaust processing performance even after the start-up. Can be. Further, according to the inventions described in claims 4 to 7, the degree of freedom in selecting the passage in which the exhaust processing member is to be interposed and the degree of freedom in designing are improved.

[0017]

According to the first aspect of the present invention, while having a simple configuration, the exhaust from the specific cylinder is always introduced into the exhaust supercharger, and the exhaust from the non-specific cylinder is
By controlling the first control valve and the second control valve in response to a request, an exhaust treatment member can be introduced into the exhaust supercharger or through the bypass passage without being introduced into the exhaust supercharger. Can be introduced. That is, according to the present invention, it is possible to achieve a high level of both early activation of the exhaust treatment member, improvement of the exhaust treatment performance, and securing of operability at a high level while having a simple configuration. The system can be provided.

According to the second aspect of the present invention, when the exhaust processing member is not activated by the pre-activation control means, the exhaust from the non-specific cylinder is exhausted through the bypass passage (exhaust). Without passing through the supercharger). Therefore, since the heat of the exhaust gas from the non-specific cylinder is not taken away by the exhaust supercharger, the exhaust gas can flow into the exhaust processing member without lowering the exhaust gas temperature so much. The early activation of the member can be promoted, so that the exhaust treatment performance can be improved.

Since the exhaust gas from the specified cylinder always flows into the exhaust supercharger even during the control by the pre-activation control means, the exhaust supercharger is kept at a predetermined level even during the control. Since the temperature of the exhaust supercharger can be increased while the supercharged state can be set, when the exhaust processing member is activated, the post-activation control means causes the exhaust from the non-specific cylinder to be transmitted to the exhaust supercharger. Even if the exhaust flow path is switched to ensure power performance by inflow, there is a concern that turbo lag (delay in boost pressure rise) will increase as in the past, and the exhaust gas will be cooled by the exhaust turbocharger to improve exhaust treatment performance. It is possible to reliably avoid the fear of a decrease.

That is, according to the present invention, it is possible to control the activation of the exhaust treatment member at an early stage, that is, the improvement of the exhaust treatment performance and the assurance of operability at a high level, with a simple structure. It becomes possible. According to the third aspect of the invention, even before the exhaust processing member is activated, when the driver requests, all exhaust (including exhaust from a non-specific cylinder) is sent to the exhaust turbocharger. Since the flow can be made to flow, the power performance can be secured (priority) according to the driver's request.

According to the present invention, in addition to the exhaust processing member into which exhaust gas flows through the exhaust passage after passing through the exhaust supercharger, a combustion chamber (cylinder) of the internal combustion engine is provided. (2) Since the exhaust processing member is provided at a position closer to (i.e., at a position having a high exhaust temperature), the exhaust processing member which can be activated early after the start-up further improves the exhaust processing performance even after the start-up. Can be. Further, the degree of freedom in selection and design can be improved.

[0022]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 2 shows an example of an exhaust system of the V-type internal combustion engine 1 including the exhaust turbocharger 5 according to the first embodiment of the present invention. V according to the present embodiment
An exhaust passage 2 for a right bank (RH), which functions as an exhaust passage for a right bank side cylinder (corresponding to a specific cylinder according to the present invention) of a type internal combustion engine (hereinafter also simply referred to as an internal combustion engine) 1, is catalyzed by a catalyst A. At the downstream side of the exhaust passage.
And the merging passage 4 is connected to an exhaust turbocharger 5. The merging passage 4 is connected to the left bank (LH) exhaust passage 3 functioning as an exhaust passage of a left bank side cylinder (corresponding to a non-specific cylinder according to the present invention).

In the exhaust passage 3 for the left bank (LH),
A flow path switching valve 3A (corresponding to a first control valve according to the present invention) for controlling the exhaust from the left bank (LH) side cylinder to flow into the merge passage 4 is provided. The switching valve 3A is driven and controlled by an engine control unit (ECU) 50 containing a microcomputer.

The exhaust turbocharger 5 as the exhaust supercharger according to the present invention is configured such that the exhaust from the exhaust passage 2 for the right bank (RH) and the exhaust passage 3 for the left bank (LH) is exhausted. When introduced into the turbine 5a, the exhaust flow pressure causes the exhaust turbine 5a to rotate, and the compressor 5b coaxially coupled to the turbine and interposed in the intake passage 9
Is rotationally driven to supply (supercharge) the intake air under pressure to the internal combustion engine 1.

A catalyst C is provided in the exhaust passage 6 on the outlet side of the exhaust turbine 5a of the exhaust turbocharger 5. Further, in the present embodiment, the left bank (LH) exhaust passage 3 is provided between the internal combustion engine 1 and the switching valve 3A.
From the exhaust passage 6, bypassing the exhaust turbine 5 a of the exhaust turbocharger 5, and
Is provided with a bypass passage 7.

Here, the exhaust passage 2 for the right bank (RH) corresponds to the exhaust passage for a specific cylinder according to the present invention.
The left bank (LH) exhaust passage 3 corresponds to the non-specific cylinder exhaust passage according to the present invention, the merge passage 4 corresponds to the merge passage according to the present invention, and the exhaust passage 6 corresponds to the exhaust according to the present invention. The bypass passage 7 corresponds to a bypass passage according to the present invention.

A catalyst B is interposed in the bypass passage 7, and a flow path switching valve 7A for controlling the flow of exhaust gas into the bypass passage 7 is provided upstream of the exhaust gas of the catalyst B. (Corresponding to a second control valve according to the present invention) is provided. The switching valve 7A is driven and controlled by the ECU 50. Incidentally, the catalyst A, the catalyst B, and the catalyst C are an oxidation catalyst, a three-way catalyst, a NOx absorbent (or a catalyst with a NOx absorbent), H
It can be a C adsorbent (or a catalyst with an HC adsorbent) or the like, that is, it can be an exhaust treatment member whose exhaust gas treatment capacity is activated by increasing the temperature. It is preferable that the catalysts A and B have a small capacity and a higher temperature-rise characteristic than the catalyst C, but the present invention is not limited to this.

The ECU 50 has an exhaust temperature (exhaust temperature).
A detection signal from the sensor 8 is input. Further, the ECU 50 stores the opening degree T of the throttle valve 10.
TVO sensor (throttle sensor) 11 for detecting VO
Is also input. Also,
The ECU 50 counts a crank unit angle signal output from the crank angle sensor 12 to the crankshaft (or camshaft) in synchronism with the engine rotation for a certain period of time, or measures the period of the crank reference angle signal. The rotation speed Ne can be detected.

Here, the control of the exhaust system performed by the ECU 50 of the present embodiment will be described with reference to the flowchart of FIG. As described below, the functions of the pre-activation control unit and the post-activation control unit according to the present invention, and the function of the driver request realization control unit are the same as those of the EC.
U50 is provided as software. In step (denoted by S in the figure; the same applies hereinafter), in the TV,
The detection value of the O sensor 11 is read.

In step 2, it is determined whether TVO is equal to or smaller than a predetermined opening (predetermined value). If YES, step 3
If NO, proceed to step 8. In step 3, the detection value of the exhaust temperature sensor 8 is read. In the following step 4, the detected value of the exhaust temperature sensor 8 is normalized. In step 5, it is determined whether the exhaust temperature is equal to or lower than the set temperature (ie, whether the catalyst C has been activated).

If YES, it is determined that the catalyst C has not been activated yet, and the routine proceeds to step 6. If NO
It is determined that the catalyst C has been activated, and the process proceeds to step 8. The heat generation can be performed by estimating the heat generation amount from the start of the internal combustion engine 1 based on the integrated value of the basic fuel injection amount TP or the deviation between the starting water temperature and the current water temperature. That is, the integrated value or weighted average value of the amount of heat ΔTp (or Qa) generated by combustion and given to the catalyst C via the exhaust gas,
Alternatively, the temperature (active state) of the catalyst C is estimated in consideration of, for example, the amount of heat that can be calculated from the heat generation amount of the internal combustion engine and the amount of heat removed from the catalyst C by the exhaust gas (correlated with the exhaust flow rate (the intake air flow rate Qa)). It is possible to make a judgment, and the accuracy of estimation / judgment can be further improved by taking into account the outside air temperature and the like.

Further, the fuel injection amount Tp, the engine speed Ne,
, The equilibrium catalyst temperature when the operation state is continued is estimated, and the current temperature of the catalyst C (or the time constant) based on the estimated value and the operation continuation time (or time constant) in the operation state (Active state) can be estimated and determined. The activation state of the catalyst C can also be determined by directly detecting the temperature of the catalyst C via a temperature sensor or the like.

In step 6, since it is determined that the catalyst C has not been activated, the switching valve 7A is opened (exhaust gas flows to the bypass path 7), and in step 7, the switching valve 3A is closed. (The flow of exhaust gas to the left bank exhaust passage 3 side is stopped), and this flow ends. On the other hand, in step 8, since it is determined that the catalyst C has been activated, the switching valve 7A is closed (the flow of exhaust gas to the bypass path 7 is stopped), and the switching valve 3A is opened in step 9. The valve is opened (the exhaust gas flows to the left bank exhaust passage 3 side), and the flow is terminated.

That is, according to the present embodiment, when the exhaust gas temperature is low at the time of cold start or the like, and the catalyst C is not activated, the switching valve 7A is opened and the switching valve 3A is closed. Therefore, the exhaust gas from the left bank (LH) side cylinder does not flow into the exhaust turbine 5a having a relatively large heat capacity, but flows into the bypass passage 7. Therefore, since the exhaust heat is not deprived by the exhaust turbocharger 5, the exhaust gas can flow into the catalysts B and C without lowering the exhaust temperature as compared with the conventional case. As compared with the case where the exhaust turbine 5a) is not bypassed, the catalyst B and the catalyst C can be activated earlier, and the exhaust gas purification performance can be improved. See timing chart.

Further, as a result of the early activation of the catalyst C, the switching valve 7A is closed earlier after the start, and
Since the switching valve 3A can be opened, it is possible to achieve high supercharging by the exhaust turbocharger 5 while maintaining the exhaust performance early after the start as compared with the related art. ) See timing chart. Further, since the exhaust gas of the right bank (RH) side cylinder is constantly flowing into the exhaust turbine 5a, the exhaust turbine 5a is rotated at a predetermined speed and the temperature is raised.
If it is determined that the catalyst C has been activated in step 8, the switching valve 7A is closed and the switching valve 3A is opened in step 8, and the exhaust gas from the left bank (LH) side cylinder is sent to the exhaust turbine 5a. Even if the flow is made to flow, there is a concern that the turbo lag (the delay in the rise of the boost pressure) increases as in the related art {see the timing chart of FIG. Turbine 5
The fear that the exhaust gas purification performance is lowered due to cooling due to a) can be reliably avoided.

Further, in this embodiment, even when the exhaust gas temperature is low such as at the time of starting the cold engine, if it is determined in step 2 that TVO is larger than the fixed opening (predetermined value), the switching valve 7A is closed. The exhaust gas from the left bank (LH) side cylinder also flows into the exhaust turbocharger 5 by opening the switching valve 3A and opening the switching valve 3A. (Priority) can be secured. That is, according to the present embodiment, both early activation of the catalyst and operability can be achieved.

When it is desired to prioritize catalyst early activation and exhaust gas purification performance over operability, steps 1 and 2 in the flowchart of FIG. 3 are omitted, and the configuration is as shown in the flowchart of FIG. (In the flowchart of FIG. 5, steps having the same contents as those in the flowchart of FIG. 3 are denoted by the same step numbers, and detailed description thereof is omitted.)

Incidentally, the state in which the switching valve 7A is opened and the switching valve 3A is closed is preferably the initial state at the time of starting. That is, immediately after the start, the possibility that the driver depresses the accelerator is relatively small as the TVO becomes larger than the predetermined value. Therefore, it is better to bypass the exhaust turbocharger 5 immediately after the start of the catalyst. This is advantageous for early activation of B and C.

If the exhaust turbocharger 5 is bypassed immediately after the start of the engine, the exhaust gas containing a large amount of unburned fuel discharged immediately after the start of the engine is cooled to a temperature below the dew point and the exhaust turbocharger 5 is cooled. This is because it is possible to suppress the fear of adhering to the exhaust turbine 5a or the like and then gradually evaporating to generate an unpleasant odor or white smoke. By the way, if the switching valve 7A is provided on the upstream side of the catalyst B as shown in FIG. 2, there is a merit that there is little fear of heat damage due to the oxidation reaction heat after the activation of the catalyst B. When there is no fear, when there is a request for layout, or the like, as pointed out in FIG. 2, the catalyst B can be interposed in the bypass passage 7 on the downstream side of the exhaust gas.

In the present embodiment, for example, a catalyst B having a relatively small capacity and good temperature rising characteristics is interposed in the bypass passage 7 so that the exhaust gas is not taken away by the exhaust turbine supercharger 5 to start the engine. Although the exhaust from the left bank side cylinder can be effectively purified from an early stage later, the above-described embodiment can be performed without interposing the catalyst B, that is, even with the system configuration as shown in FIG. Various functions and effects of the embodiment can be obtained, and therefore, the present invention can be applied even when the catalyst B is not interposed.

In FIG. 2, for example, a catalyst A having a relatively small capacity and good temperature-rise characteristics is interposed in the exhaust passage 2 for the right bank on the upstream side of the exhaust turbocharger 5. 5
The exhaust gas from the right bank side cylinder can be effectively purified from the early stage after the start by preventing exhaust heat from being deprived of the exhaust gas, but from FIG. 2 (or FIG. 6), even if the catalyst A is omitted, The various functions and effects of the present embodiment described above can be obtained, and therefore, the present invention can be applied even when the catalyst A is not interposed (and when the catalysts A and B are not provided). is there.

Next, a second embodiment of the present invention will be described. In the second embodiment, as shown in FIG. 7, the left bank exhaust passage 3 is different from the system configuration in the first embodiment of FIG. 2 in which the catalyst B is interposed in the bypass passage 7. It has been changed to interpose the catalyst B.
Other configurations are the same as those of the first embodiment. In FIG. 7, the same elements as those of the first embodiment shown in FIG. 2 are denoted by the same reference numerals, and detailed description thereof is omitted. I will.

The control performed by the ECU 50 is the same as that of the first embodiment, and the flowchart of FIG. 3 (or FIG. 5) is executed. With the configuration according to the second embodiment, the catalyst B can be disposed closer to the combustion chamber (cylinder) than when the catalyst B is interposed in the bypass passage 7 as in the first embodiment. Therefore, a decrease in the temperature of the exhaust gas flowing into the catalyst B can be suppressed as much as possible, whereby early activation of the catalyst B can be promoted.

Therefore, according to the second embodiment, the same operation and effects as those of the first embodiment can be obtained, and the exhaust gas purifying performance can be further improved. next,
A third embodiment of the present invention will be described. In the third embodiment, as shown in FIG. 8, the catalyst A is interposed in the merging passage 4 in the system configuration of FIG. 2 in the first embodiment.

Other configurations are the same as those of the first embodiment. In FIG. 8, the same elements as those of the first embodiment shown in FIG. Will be omitted. The control performed by the ECU 50 is the same as that of the first embodiment, and the flowchart of FIG. 3 (or FIG. 5) is executed.

According to the configuration of the third embodiment, the activation of the catalyst C is higher than that of the first embodiment in which the catalyst A is interposed in the right bank exhaust passage 2 as shown in FIG. If the exhaust turbocharger 5 is not to be bypassed before (for example, if there is a driver's acceleration request or high output request before activation of the catalyst C), the exhaust from the left bank side cylinder is also reduced. Since it can flow into the catalyst A, it can respond to the driver's acceleration or high output demand, etc.
At the same time, when the catalyst A is not activated, the activation of the catalyst A can be promoted, and when the catalyst A is activated, the exhaust from the left bank side cylinder can be satisfactorily purified by the catalyst A. Therefore, both the operability and the exhaust gas purification performance can be further enhanced as compared with the first embodiment.

In each of the above embodiments, the case where the exhaust turbocharger 5 is provided has been described. However, the present invention is not limited to this. When a so-called complex supercharger (supercharger using an exhaust pressure wave) is used, that is, an exhaust supercharger using exhaust energy can be interposed in the exhaust passage. It is.

The present invention is not limited to the V-type engine,
The same applies to horizontally opposed engines. Further, the present invention provides an in-line type engine in which cylinders are divided into at least two cylinder groups (for example, in the case of in-line six cylinders,
The present invention is also applicable to a case where the engine is divided into two cylinder groups (three cylinders before and after three cylinders). That is, what has been described in the above embodiments is merely an example, and the present invention is not limited to this. The present invention includes a plurality of cylinders, and guides exhaust gas from at least one specific cylinder of the plurality of cylinders to a merged passage through a specific cylinder exhaust passage, and then guides the exhaust gas to an exhaust supercharger. The exhaust gas from the non-specific cylinder is guided to the exhaust supercharger through the non-specific cylinder exhaust passage through the exhaust passage, and then the exhaust gas passing through the exhaust supercharger is exhausted after passing through the exhaust supercharger. The present invention can be applied to all exhaust systems of an internal combustion engine that is guided to an exhaust processing member via a.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of the invention according to claim 2;

FIG. 2 is a system configuration diagram according to the first embodiment of the present invention.

FIG. 3 is a flowchart for explaining exhaust system control in the embodiment.

FIG. 4 is a timing chart for explaining the operation and effect in the embodiment.

FIG. 5 is a flowchart for explaining another example of the exhaust system control in the embodiment.

FIG. 6 is a diagram showing another example of the system configuration in the embodiment.

FIG. 7 is a system configuration diagram according to a second embodiment of the present invention.

FIG. 8 is a system configuration diagram according to a third embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 internal combustion engine 2 right bank exhaust passage (exhaust passage for specific cylinder) 3 left bank exhaust passage (exhaust passage for non-specific cylinder) 4 merge passage 5 exhaust turbocharger 6 exhaust passage (exhaust after passing through exhaust supercharger) 7) Bypass passage 8 Exhaust temperature sensor 9 Intake passage 10 Throttle valve 11 TVO sensor 50 Engine control unit (ECU) A Catalyst (exhaust treatment member) B Catalyst (exhaust treatment member) C Catalyst (exhaust treatment member)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI F02B 37/12 302 F02B 37/12 302A

Claims (7)

[Claims] An exhaust system comprising a plurality of cylinders, wherein exhaust gas from at least one specific cylinder among the plurality of cylinders is guided to a merging passage through a specific cylinder exhaust passage and then to an exhaust supercharger, and the specific cylinder The exhaust from the non-specific cylinder other than the non-specific cylinder is guided to the merger passage through the non-specific cylinder exhaust passage and then to the exhaust supercharger, and the exhaust gas passing through the exhaust supercharger is exhausted after passing through the exhaust supercharger. An exhaust system for an internal combustion engine configured to be guided to an exhaust processing member through a passage, wherein the exhaust system branches off from the non-specific cylinder exhaust passage and bypasses the exhaust supercharger at an exhaust upstream side of the exhaust processing member. A bypass passage connected to the exhaust passage after passing through the exhaust supercharger; and a bypass passage provided at the exhaust passage for the non-specific cylinder downstream of the branch from the bypass passage. Exhaust to passage A first control valve that controls the inflow, and a second control valve that is provided in the bypass passage and controls the inflow of exhaust gas from the bypass passage into the exhaust passage after passing through the exhaust supercharger. An exhaust system for an internal combustion engine. 2. The method according to claim 1, further comprising: controlling the first control valve to stop the flow of exhaust gas from the non-specific cylinder exhaust passage to the merge passage before activating the exhaust treatment member. Controlling the first control valve to control the first control valve after the exhaust treatment member is activated, by controlling the exhaust gas to flow into the exhaust passage after passing through the exhaust supercharger through the bypass passage. Exhaust gas flows into the merging passage through a non-specific cylinder exhaust passage and controls the second control valve,
2. The exhaust system for an internal combustion engine according to claim 1, further comprising: after-activation control means for stopping the flow of exhaust gas from the bypass passage into the exhaust passage after passing through the exhaust supercharger. 3. Even before the exhaust treatment member is activated, when there is a driver's request, the control by the pre-activation control means is stopped, and the first control valve is controlled. An operation of causing exhaust gas to flow into the merged passage through a specific cylinder exhaust passage, and controlling the second control valve to stop the flow of exhaust gas from the bypass passage into the exhaust passage after passing through the exhaust supercharger. 3. The exhaust system for an internal combustion engine according to claim 2, wherein the system includes a user request realization control unit. 4. The exhaust system for an internal combustion engine according to claim 1, wherein an exhaust processing member is interposed in the exhaust passage for the specific cylinder. 5. An exhaust system for an internal combustion engine according to claim 1, wherein an exhaust processing member is interposed in said joining passage. 6. An exhaust system for an internal combustion engine according to claim 1, wherein an exhaust processing member is interposed in said bypass passage. 7. An exhaust processing member is interposed in an exhaust passage for a non-specific cylinder upstream of the branch from the bypass passage. Exhaust system for internal combustion engines.