JP2003003836A - Exhaust bypass device for turbocharger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To promote the early activation of a catalyst converter at cold start by increasing the bypass flow amount of an exhaust gas in an exhaust bypass device for a turbocharger. SOLUTION: In the turbine unit 12 of a turbocharger 33, an exhaust bypass passage 34 is formed independently of an exhaust passage 16 passing through a turbine impeller, and the bypass flow amount is sufficiently secured by approximately equalizing the flow path area of the exhaust bypass passage 34 to that of the exhaust passage 16. An actuator 39 is controlled by an engine control ECU, and the bypass passage 34 is opened or closed by a bypass control valve. The bypass control valve is opened at cold start to make an exhaust gas directly flow in the catalyst converter through the bypass passage 34 bypassing the exhaust passage 16. Thereby, the lowering of exhaust temperature by a turbine is eliminated to elevate a catalyst temperature quickly and thus, the early activation of a catalyst can be promoted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a turbocharger exhaust bypass device for bypassing an exhaust passage passing through a turbine in an engine equipped with a turbocharger.

[0002]

2. Description of the Related Art An engine equipped with a turbocharger obtains a high output by using a pressure of exhaust gas to drive a turbine of the turbocharger and supercharging intake air by a compressor connected to the turbine. . Further, in general, the turbocharger is provided with an exhaust bypass device, which opens the wastegate valve when the supercharging pressure reaches a predetermined pressure to release the exhaust gas pressure to the downstream side of the turbine. , It prevents the boost pressure from rising excessively.

An exhaust bypass device for a conventional turbocharger will be described with reference to FIGS. 11 to 17. Figure 11
FIG. 1 shows an engine equipped with a turbocharger having an exhaust bypass device. As shown in FIG. 11, the engine 1 is
In an in-line three-cylinder engine for an automobile, a turbine side of a turbocharger 3 is connected to a collecting portion of an exhaust manifold 2, and a catalytic converter 4 is connected to a downstream side thereof. An air cleaner 6 is connected to the compressor-side inlet of the turbocharger 3 via an air duct 5, and a throttle valve (not shown) is connected to the compressor-side outlet via an intercooler 7. . In FIG. 11, reference numeral 8 is a flywheel connected to the crankshaft, 9 is an oil pan, 10 is an oil filter, and 11 is a water pump.

As shown in FIGS. 12 to 15, the turbocharger 3 includes a turbine unit 12 and a compressor unit 13 each having a turbine impeller (not shown) and a compressor impeller (not shown) coaxially mounted. ing. In the housing of the turbine unit 12, from the turbine inlet 14 that opens in a substantially tangential direction,
An exhaust passage 16 (see the hatched portion in FIG. 12) that extends through the turbine impeller to the turbine outlet 15 that opens in the substantially axial direction is formed. Compressor unit 13
In the housing of, from the compressor inlet 17 opening in the substantially axial direction, through the compressor impeller,
Compressor outlet 18 that opens in a substantially tangential direction
An intake passage (not shown) extending to is provided.

Further, the housing of the turbine unit 12 branches off from the middle of the exhaust passage 16 and bypasses the turbine impeller, and the turbine outlet 15 is provided in the axial direction of the housing.
An exhaust bypass passage 20 that opens into a flange 19 that is common to
(See the shaded area in FIG. 12). The exhaust bypass passage 20 has a wastegate valve 21 that opens and closes it.
(See Fig. 13) is provided and wastegate valve 21
Diaphragm actuator via link 22
It is connected to 23 actuating rods 24.

In the actuator 23, the input section 25 is a pipe line.
It is connected to the downstream side of the compressor impeller of the intake passage via 26, and normally, when the waste gate valve 21 is closed and the intake pressure (supercharging pressure) in the intake passage reaches a predetermined pressure, that pressure is reduced. It receives and opens the waste gate valve 21. Note that, as shown in FIG. 14, the diameter d ₁ of the exhaust bypass passage 20 is considerably smaller than the diameter D ₁ of the exhaust passage 16 (turbine outlet 15).

As shown in FIGS. 16 and 17, the exhaust manifold 2 is composed of three branch pipes having a first port 27, a second port 28, and a third port 29, and one collecting portion 30.
The collecting portion 30 is arranged near between the port 28 and the port 3 and the flange portion 31 formed at the end of the collecting portion 30.
The flange portion 32 formed at the turbine inlet 14 of the turbocharger 3 is coupled to the.

With this configuration, the exhaust gas discharged from the combustion chamber of the engine 1 passes through the exhaust manifold 2, flows from the turbine inlet 14 of the turbocharger 3 into the exhaust passage 16, drives the turbine impeller, and then the turbine outlet. 15
After being purified through the catalytic converter 4,
It is discharged to the outside through an exhaust pipe and a silencer (not shown). As a result, the compressor impeller connected to the turbine impeller rotates and supercharges the intake air.

At this time, when the supercharging pressure in the intake passage exceeds the set pressure, the actuator 23 operates in response to the pressure to open the waste gate valve 21. As a result, the exhaust gas passing through the exhaust passage 16 is bypassed to the downstream side of the turbine impeller through the exhaust bypass passage 20, so that it is possible to prevent the boost pressure from rising excessively.

[0010]

However, the conventional turbocharger bypass device described above has the following problems. Since the flow passage area of the exhaust bypass passage is small, the bypass flow rate of exhaust gas is small. Exhaust bypass passage 16 is the exhaust passage 16 inside the turbine housing (scroll)
Since it is branched from the middle of the,
When the valve 21 is opened, the flow direction of the exhaust gas changes greatly, so that pulsation easily occurs, which causes noise and vibration. The waste gate valve 21 is controlled only by the pressure in the intake passage on the compressor side, and is used only to prevent the boost pressure from rising excessively.

On the other hand, there are the following problems in general engines equipped with a turbocharger. Generally, immediately after a cold start of the engine, it is necessary to raise the catalyst temperature as quickly as possible in order to activate the catalytic converter. However, when the exhaust gas passes through the turbocharger, it is absorbed by parts with large heat capacity such as the turbine housing and impeller, and the exhaust temperature decreases due to the work to drive the turbine. It takes a considerable time for the catalyst temperature of the catalytic converter to rise to the activation temperature.

[0012] The present invention has been made in view of the above points, and provides a turbocharger capable of increasing the bypass flow rate of exhaust gas and achieving early activation of a catalytic converter during cold start. An object is to provide an exhaust bypass device.

[0013]

In order to solve the above-mentioned problems, the invention according to claim 1 comprises a turbine unit and a compressor unit, wherein a scroll and a scroll are bypassed in a housing of the turbine unit. An exhaust bypass device for a turbocharger, which is provided with an exhaust bypass passage, is provided with an on-off valve for opening and closing the exhaust bypass passage, and has a flow rate control means for controlling the on-off valve to control the flow rate in the exhaust bypass passage, The flow passage area of the exhaust bypass passage is substantially equal to the flow passage area of the exhaust passage. With this configuration, when the on-off valve is opened by the flow rate control means,
The flow rate of the exhaust gas flowing through the exhaust bypass passage becomes sufficiently large. According to a second aspect of the invention, in the configuration of the first aspect, the flow rate control means opens when the catalyst temperature of the catalytic converter connected to the downstream side of the turbocharger is lower than a predetermined activation temperature. It is characterized by With this configuration, before the catalyst temperature reaches the activation temperature, the open / close valve is opened, and the exhaust gas bypasses the turbine through the exhaust bypass passage and directly flows to the catalytic converter. The invention according to claim 3 is characterized in that, in the structure according to claim 1 or 2, the exhaust bypass passage is independent of the exhaust passage from an inlet to an outlet in a housing of the turbine unit.
With this configuration, in the housing of the turbine unit, the exhaust gas does not branch from the exhaust passage to the exhaust bypass passage, so that pulsation of exhaust gas is less likely to occur. The invention according to claim 4 is characterized in that, in the structure according to claim 3, the inlet and the outlet of the exhaust bypass passage are oriented in directions substantially orthogonal to each other. With this configuration, the inlet and outlet of the exhaust bypass passage can be oriented in substantially the same direction as the inlet and outlet of the exhaust passage of the turbine housing. According to a fifth aspect of the present invention, in the configuration of the third aspect, the inlet and the outlet of the exhaust bypass passage are arranged substantially in a straight line and are directed in opposite directions to each other. With this configuration, the flow of exhaust gas in the exhaust bypass passage can be made smooth. According to a sixth aspect of the present invention, in the configuration of the above third to fifth, the exhaust manifold consisting of a plurality of branch pipes and one collecting portion is connected to the upstream side of the turbocharger, and the collecting portion is located at any position. It is characterized in that it is branched into two passages, and the branched passages are respectively connected to the exhaust passage and the exhaust bypass passage. With this configuration,
Since the exhaust gas is branched from the collecting portion of the exhaust manifold to the exhaust passage or the exhaust bypass passage, the pulsation of the exhaust gas is less likely to occur.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below in detail with reference to the drawings. The exhaust bypass device for the turbocharger of the present embodiment is applied to the same engine as the engine shown in FIG. 11, and in the following description, the same parts as those of the conventional example are the same. Only the different parts will be described in detail with reference numerals.

A first embodiment of the present invention will be described with reference to FIGS. 1 to 7. As shown in FIGS. 1 to 5,
In the turbocharger 33 according to this embodiment, the exhaust bypass passage 34 is integrally formed in the housing of the turbine unit 12 independently of the exhaust passage 16. The inlet 35 of the exhaust bypass passage 34 and the turbine inlet 14 (the inlet of the exhaust passage 16) are formed independently but have a common flange portion 36, and the outlet 37 of the bypass passage 34 and the turbine. The outlet 15 (the outlet of the exhaust passage 16) is formed independently, but is arranged inside the common flange portion 19. In the exhaust bypass passage 34, an inlet 35 and an outlet 37 are provided at the turbine inlet 14
The turbine outlet 15 is opened in the same direction as the turbine outlet 15, and is bent at a substantially right angle (θ = 90 °). Further, the exhaust bypass passage 34 has substantially the same flow passage area as the exhaust passage 16, and the diameter d _{2 of the} inlet 35 is substantially the same as the diameter D ₂ of the turbine inlet 14. The diameter d ₃ of the outlet 37 of the exhaust bypass passage 34 is slightly smaller than the diameter D ₃ of the turbine outlet 15.

A bypass control valve 38 (open / close valve) for opening / closing the outlet 37 is provided at the opening of the outlet 37 of the exhaust bypass passage 34. The bypass control valve 38 is connected to a solenoid-type actuator 39 mounted on the compressor unit 13 side via a link 40 and an operating rod 41. The actuator 39 is connected to the engine ECU (not shown). The engine ECU is a flow rate control means that controls the bypass control valve 38 to control the flow rate of the exhaust bypass passage 34, and the actuator 39 is controlled by a command signal.
To close the bypass control valve 38, and when the boost pressure exceeds the preset value, the bypass control valve 38
open. In addition, when the engine 1 is cold started, the bypass control valve 38 is opened until the catalytic converter 4 reaches a predetermined activation temperature. It should be noted that the actuator 39 may be arranged at other parts, but in the present embodiment, it is arranged on the compressor side, which is relatively hard to reach a high temperature, avoiding the turbine side which becomes a high temperature due to the exhaust gas.

Further, in this embodiment, as shown in FIGS. 6 and 7, the exhaust manifold 39 includes a second port 28 and a third port 28.
Passages 40 and 41 respectively connected to the turbine inlet 14 of the turbocharger 33 and the inlet 35 of the exhaust bypass passage 34 are branched from the collecting portion 30 arranged between the port 29 and the port 29. These two passages 40, 41 have substantially the same passage area,
Further, they are formed to have substantially the same length. At the tip of the two passages 40 and 41, the turbine inlet 14 and the exhaust bypass passage 34
The flange portion 42 connected to the flange portion 36 on the inlet 35 side is integrally formed. In the exhaust manifold 39, the collecting portion 30 can be branched into the passages 40 and 41 at any position.

The operation of the present embodiment configured as described above will be described below. When the boost pressure exceeds a predetermined set value, a command signal from the engine ECU opens the bypass control valve 38, and exhaust gas bypasses the turbine impeller (turbine) through the exhaust bypass passage 34. Prevents an excessive rise in supply pressure. At this time, since the exhaust gas is branched from the collecting portion 30 of the exhaust manifold 39 and flows through the passage 41 and the exhaust bypass passage 34, its flow direction does not change significantly, and pulsation does not easily occur, so that noise and vibration Occurrence can be suppressed.

When the engine 1 is cold started, a command signal from the engine ECU is used to bypass the bypass control valve 38.
, The exhaust gas flows through the passage 41 of the exhaust manifold 39 and the exhaust bypass passage 34 directly to the catalytic converter. At this time, since the flow passage area of the exhaust bypass passage 34 is almost the same as the flow passage area of the exhaust passage 16,
A sufficient exhaust gas flow rate can be secured. As a result, the exhaust temperature does not decrease due to heat absorption by the turbine housing, a component having a large heat capacity such as an impeller, and work for driving the turbine, and high-temperature exhaust gas is directly supplied to the catalytic converter 4. The temperature of the catalytic converter 4 can be raised quickly, and the exhaust gas purification capacity can be improved by early activation of the catalytic converter.

After that, when the temperature of the catalytic converter 4 reaches a predetermined activation temperature, the bypass control valve 38 is closed by the command signal of the engine ECU, and the exhaust bypass passage 34
Bypass is stopped, exhaust gas is circulated through the exhaust passage 16, and the turbine is driven to start supercharging. In this embodiment, the catalyst temperature is used as a parameter to control the opening / closing of the bypass control valve 38, but other parameters generally used for engine control (engine water temperature, intake air temperature, oil temperature, throttle opening, It is also possible to control the opening / closing by using the vehicle speed, the shift signal, etc.).

Next, a second embodiment of the present invention will be described with reference to FIGS. In the following description, the same parts as those in the first embodiment will be designated by the same reference numerals, and only different parts will be described in detail.

As shown in FIGS. 8 to 10, in the exhaust bypass device according to the second embodiment, the exhaust bypass passage 43 is
It extends from the entrance 35 in a substantially straight line. A conduit member 44 having a substantially L-shaped passage is attached to the turbine outlet, and an outlet 45 of the exhaust bypass passage 43 and an outlet 46 of the conduit member 44 are attached.
And are opened substantially in parallel in the same direction (opposite to the inlet 35 of the exhaust bypass passage 43 and the turbine inlet 14). Then, to these outlets 45, 46, the catalytic converter 4 having a flange portion (not shown) having a shape matching the shape of the flange portion 47 is connected.

With this configuration, at the time of cold start, the exhaust gas flows directly to the catalytic converter 4 through the exhaust bypass passage 43 in which the inlet 35 and the outlet 45 are arranged in a straight line. The temperature drop of the exhaust gas can be reduced, and more rapid activation of the catalyst can be achieved. Furthermore, since it was formed on a substantially straight line,
The turbine unit housing can be easily manufactured, and the number of manufacturing steps can be reduced.

[0024]

As described in detail above, according to the exhaust bypass device for a turbocharger of claim 1, the flow passage area of the exhaust bypass passage is made substantially equal to the flow passage area of the exhaust passage, so that the valve means is provided. When the valve is opened, the flow rate of the exhaust gas flowing through the exhaust bypass passage can be sufficiently increased. According to the exhaust bypass device of the turbocharger according to claim 2, at the time of cold start of the engine, the valve means is opened and the exhaust gas bypasses the turbine through the exhaust bypass passage and directly flows to the catalytic converter. The decrease in the temperature of the exhaust gas can be reduced, the catalyst temperature can be raised quickly, and the exhaust gas purification capacity can be improved by the early activation of the catalytic converter. According to the exhaust bypass device for a turbocharger of claim 3, since exhaust gas does not branch from the exhaust passage to the exhaust bypass passage in the housing of the turbine, exhaust pulsation is less likely to occur, and vibration and noise are suppressed. can do. According to the exhaust bypass device for the turbocharger of claim 4, the inlet and outlet of the exhaust bypass passage can be directed in substantially the same direction as the inlet and outlet of the exhaust passage of the housing of the turbine, and the structure can be simplified. it can. According to the exhaust bypass device for the turbocharger of claim 5, the flow of exhaust gas in the exhaust bypass passage can be made smooth, and early activation of the catalyst can be promoted. According to the exhaust bypass device for the turbocharger of claim 6, since the exhaust gas is branched from the collecting portion of the exhaust manifold to the exhaust passage or the exhaust bypass passage, pulsation of the exhaust gas is less likely to occur,
Generation of vibration and noise can be suppressed.

[Brief description of drawings]

FIG. 1 is a front view of a turbocharger including an exhaust bypass device according to a first embodiment of the present invention.

2 is a side view of the device of FIG. 1. FIG.

FIG. 3 is a front view of outlet portions of an exhaust passage and an exhaust bypass passage of the device of FIG.

4 is a front view of an inlet portion of an exhaust passage and an exhaust bypass passage of the device shown in FIG.

5 is a schematic perspective view of a turbine unit showing an arrangement of an exhaust passage and an exhaust bypass passage of the apparatus shown in FIG.

6 is a plan view of an exhaust manifold connected to the apparatus of FIG.

7 is a side view of the exhaust manifold of FIG.

FIG. 8 is a front view of a turbine portion of a turbocharger including an exhaust bypass device according to a second embodiment of the present invention.

9 is a side view of the turbine portion of the turbocharger of FIG.

10 is a front view of an inlet portion of an exhaust passage and an exhaust bypass passage of the device shown in FIG.

FIG. 11 is a side view of an engine equipped with a turbocharger having an exhaust bypass device.

FIG. 12 is a front view of a turbocharger including a conventional exhaust bypass device.

13 is a side view of the device of FIG.

FIG. 14 is a front view of the outlet portions of the exhaust passage and the exhaust bypass passage of the device of FIG.

15 is a front view of an inlet portion of an exhaust passage of the apparatus shown in FIG.

16 is a plan view of an exhaust manifold connected to the apparatus of FIG.

FIG. 17 is a side view of the exhaust manifold of FIG.

[Explanation of symbols]

4 catalytic converter 12 turbine unit 13 Compressor unit 16 Exhaust passage (scroll) 30 Assembly Department 33 Turbocharger 34 Exhaust bypass passage 35 entrance 37 exit 38 Bypass control valve (open / close valve) 39 Exhaust manifold 40,41 aisle

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F02B 39/16 F02B 37/12 301E F term (reference) 3G005 EA16 FA35 FA45 GB22 GB28 GB86 GD09 HA18 JA12 JA16 JA17 3G091 AA02 AA10 AB01 BA03 CA13 CB08 DA01 DA02 DB10 EA07 EA15 EA16 EA18 EA39 EA40 FA02 FA04 FB02 FC07 HB03 HB06

Claims (6)

[Claims] 1. A turbine unit and a compressor unit are provided, and a housing of the turbine unit is provided.
A turbo equipped with a scroll and an exhaust bypass passage that bypasses the scroll, an opening / closing valve that opens and closes the exhaust bypass passage, and a flow rate control unit that controls the opening / closing valve to control the flow rate in the exhaust bypass passage. In the exhaust bypass device of the charger, the exhaust bypass device of the turbocharger is characterized in that the flow passage area of the exhaust bypass passage is substantially equal to the flow passage area of the exhaust passage. 2. The flow rate control means opens the on-off valve when the catalyst temperature of a catalytic converter connected to the downstream side of the turbocharger is lower than a predetermined activation temperature. Exhaust bypass device for turbocharger as described in 1. 3. The exhaust bypass passage for a turbocharger according to claim 1, wherein the exhaust bypass passage is independent of the exhaust passage from an inlet to an outlet in the housing of the turbine unit. . 4. The exhaust bypass device for a turbocharger according to claim 3, wherein an inlet and an outlet of the exhaust bypass passage are oriented in directions substantially orthogonal to each other. 5. The exhaust bypass device for a turbocharger according to claim 3, wherein an inlet and an outlet of the exhaust bypass passage are arranged in a substantially straight line and are directed in opposite directions. 6. An exhaust manifold comprising a plurality of branch pipes and one collecting portion is connected to an upstream side of the turbocharger, and the collecting portion is branched into two passages at arbitrary positions,
4. The branched passage is connected to the exhaust passage and the exhaust bypass passage, respectively.
6. An exhaust bypass device for a turbocharger according to any one of 1 to 5.