JPH0972210A - Selector valve and purifying facility for exhaust gas - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control the chattering of a valve plate by controlling pressure unbalance between the obverse side and the reverse side of the valve plate. SOLUTION: An opening area of a valve opening 52 of bypass passage side is smaller than that of a valve opening 42 of exhaust main passage side, thereby reducing the amount of unbalance between force acting on the bypass passage 5 side of a valve plate 60 and force acting on the exhaust main passage 5 side, which controls chattering produced on the valve plate 60.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine (internal combustion engine).
The present invention relates to the exhaust gas switching valve device and the exhaust gas purifying device, and is suitable for use in automobiles.

[0002]

2. Description of the Related Art An exhaust gas purifying apparatus using a carrier carrying a noble metal (platinum, rhodium, etc.) as a catalyst is known as one type of purifying apparatus for purifying exhaust gas from an automobile. In order to purify exhaust gas by this method, it is generally necessary to bring the catalyst to a catalyst activation temperature (300 to 400 ° C.).

However, there is a problem that the exhaust gas is hardly purified because the catalyst has not reached the catalyst activation temperature immediately after the engine is started. Therefore, in order to solve the above-mentioned problem, it is the current situation that the above-mentioned catalyst is arranged in the vicinity of the engine and the heat of exhaust gas is given to the above-mentioned catalyst as much as possible so that the above-mentioned catalyst reaches the catalyst activation temperature at an early stage. is there.

Alternatively, the carrier supporting the catalyst is metalized to reduce the heat capacity, thereby aiming for early warm-up of the catalyst, and a catalyst with a heater having a heater built into the carrier (hereinafter referred to as "E").
Abbreviated as HC. The technique for activating the catalyst at an early stage by using (1) is also known. And, naturally, a combination of these is also a known technique. In order to meet the increasingly stringent exhaust gas regulations (US, Europe), a higher exhaust gas purification rate is required. It will be closer. Along with this, the temperature of the exhaust gas after the engine has warmed up increases.

By the way, since the catalyst deteriorates when exposed to high temperature conditions, as described above, bringing the catalyst closer to the engine cannot always satisfy the requirement for a high purification rate of exhaust gas. That is, since the temperature of the exhaust gas after the engine is warmed up becomes higher by bringing the catalyst mounting position closer to the engine, deterioration of the catalyst causes a reduction in the exhaust gas purification rate.

In order to solve the problem of catalyst deterioration due to heat, Japanese Patent Laying-Open No. 4-60108 discloses that an exhaust pipe immediately below the engine is branched to form an exhaust main flow path for exhaust gas.
A bypass flow passage arranged in parallel with the exhaust main flow passage is installed, an EHC carrying a catalyst is installed in the bypass flow passage, and the exhaust main flow passage and the bypass flow passage are joined again to form one An exhaust gas purifying device has been proposed in which a main catalyst device is installed in a portion that becomes an exhaust pipe.

In the device described in this publication, the exhaust gas is caused to flow through the bypass passage only when the exhaust gas is at a low temperature,
When the temperature of the exhaust gas becomes high, the exhaust gas is made to flow through the main exhaust passage. As a result, when the exhaust gas is at a low temperature, the heater catalyst arranged in the bypass flow passage causes
Exhaust gas is purified. At this time, the main catalyst device is gradually activated by the heat of the exhaust gas and the reaction heat / heater heat of the heater catalyst, and when the main catalyst device is activated, the exhaust flow passage is switched so that the exhaust gas flows to the exhaust main flow passage. ing.

Therefore, in this device, an exhaust gas switching valve device for switching the flow of exhaust gas is provided at a branch portion between the exhaust main flow path and the bypass flow path.

[0009]

By the way, the above exhaust gas purifying apparatus has the above-mentioned exhaust gas switching valve in which the bypass passage is closed under conditions of high exhaust temperature and large displacement such as when the engine is under heavy load. There is a problem that chattering occurs on the valve plate of the device. Then, the present inventors have conducted various research and studies and found that chattering occurs due to the following causes.

That is, since the exhaust gas discharged from the engine is intermittently discharged in each exhaust stroke, exhaust pulsation occurs in the exhaust pipe, which causes pressure pulsation in the exhaust pressure. Therefore, in the state where the valve plate closes the bypass flow passage, as shown in FIG.
Also, due to the difference in reaching distance between the pressure acting on the valve plate 60 surface on the bypass flow passage 5 side via the bypass flow passage 5 and the pressure acting on the valve plate 60 surface on the exhaust main flow passage 4 side, the pressure pulsation is A phase difference occurs. Then, due to the phase difference of the pressure pulsation, pressure imbalance occurs on both front and back surfaces of the valve plate 60.

When the engine load is high when the valve plate 60 closes the bypass passage 5, the amplitude of the pressure pulsation becomes large, so that the pressure imbalance becomes large on both the front and back sides of the valve plate 60, and the front and back sides of the valve plate 60 become large. Force acting on both sides (product of pressure and area on which pressure acts)
Due to the imbalance, the chattering occurred on the valve plate 60.

In view of the above points, an object of the present invention is to provide an exhaust gas switching valve device that suppresses chattering of a valve plate by suppressing an imbalance of forces acting on both front and back surfaces of the valve plate. To do.

[0013]

SUMMARY OF THE INVENTION To achieve the above object, the following technical means are used. In the invention according to claim 1, an exhaust gas switching valve device for switching between a bypass passage (5) through which exhaust gas flows when the engine is cold and an exhaust main passage (4) through which exhaust gas flows when the engine is warmed up ( In 6), the opening area of the bypass flow passage side valve opening (52) provided so as to communicate with the bypass flow passage (5) is the exhaust main passage side valve opening provided so as to communicate with the exhaust main flow passage (4). It is smaller than the opening area of (42).

According to the second aspect of the invention, the exhaust main flow passage side valve opening (42) and the bypass flow passage side valve opening (52) are provided at the connecting portion of the bypass flow passage (5) and the exhaust main flow passage (4). ing. The valve operating mechanism (69) that transmits the movement of the actuator (100) to the valve body (60) that opens and closes both valve openings (42, 52) includes a rotating shaft (63, 6).
5), bearings (64, 66) and a connecting member (61), all of which are configured to be located in the bypass flow path (5).

According to a third aspect of the present invention, in the exhaust gas switching valve device according to the second aspect, the rotary shafts (63, 6) are provided.
The dimension (R) from the center of rotation of 5) to the center of the bypass passage side valve opening (52) is from the center of rotation of the rotating shafts (63, 65) to the connecting portion between the valve body (60) and the connecting member (61). It is characterized in that it is smaller than the turning radius (r). According to a fourth aspect of the invention, in the exhaust gas switching valve device according to any one of the first to third aspects, the opening area of the bypass flow passage side valve opening (52) is equal to the exhaust main flow passage side valve opening (4).
The opening area of 2) is 30% to 80%.

According to a fifth aspect of the present invention, in the exhaust gas purifying apparatus, the flow of the exhaust gas is switched to either the bypass flow passage (5) or the main exhaust flow passage (4).
Through the exhaust gas switching valve device, the exhaust gas is circulated through the bypass flow passage (5) when the engine is cold, and the exhaust gas is discharged through the exhaust main flow passage (4) when the engine is warmed up. It is characterized in that it is controlled so as to be distributed.

Next, the function and effect of the above invention will be described. According to the invention described in claims 1 to 5, since the opening area of the bypass flow passage side valve opening (52) is smaller than the opening area of the exhaust main flow passage side valve opening (42), the valve body (60) is bypassed. The force acting on the bypass flow passage (5) side of the valve body (60) (the working pressure on the bypass flow passage 5 side and the opening area of the bypass flow passage side valve opening 52 with the flow passage side valve opening (52) closed). Product of
And the amount of unbalance between the force acting on the exhaust main flow passage (5) side (the product of the pressure acting on the exhaust main flow passage 5 side and the opening area of the bypass flow passage side valve opening 52) can be reduced. Therefore, it is possible to suppress chattering occurring in the valve body (60) due to imbalance of forces acting on both front and back surfaces of the valve body (60).

Further, since the unbalance amount of the forces acting on the valve body (60) can be reduced, the acting force for pressing the valve body (60) against the bypass passage side valve opening (52) can be reduced. it can. Therefore, the valve operating mechanism (6
9) the rotating shafts (63, 65) and the bearings (64,
Since the mechanical load of 66) and the connecting member (61) is reduced, the size of these and the actuator (100) can be reduced.

By the way, by appropriately selecting the length of the bypass flow path (5), the phase difference of the pressure pulsation is set to 180 degrees, and a means for canceling the pressure pulsation and suppressing chattering can be considered. Since the frequency of the pressure pulsation changes depending on the engine speed, it is difficult to stably cancel the pressure pulsation and suppress chattering in a wide engine speed range. However, according to the present invention, as described above, chattering can be suppressed regardless of the engine speed.

According to the second aspect of the present invention, since the components constituting the valve operating mechanism (69) are arranged so as to be located in the bypass flow passage (5), the bypass flow passage (5) is provided. When the valve is closed and the high-temperature exhaust gas after engine warm-up is caused to flow through the exhaust main flow path (4), the components constituting the valve operating mechanism (69) are not directly exposed to the high-temperature exhaust gas. Therefore, each of these members can suppress thermal deterioration.

Further, since thermal deformation and thermal strain are suppressed, it is possible to further suppress malfunctions due to twisting of the rotating shafts (63, 65). According to the third aspect of the invention, the dimension (R) from the center of rotation of the rotary shafts (63, 65) to the center of the bypass flow passage side valve opening (52) is the rotary shaft (6
3, 65) from the center of rotation of the valve body (60) and the connecting member (6
Since it is smaller than the radius of gyration (r) up to the connecting portion with 1), the bypass passage side valve port (52) is connected to the rotary shafts (63, 6).
It can be brought close to the center of rotation of 5). Therefore,
It is possible to reduce the size of the exhaust gas switching valve device.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention shown in the drawings will be described. (First Embodiment) FIG. 1 shows a first embodiment in which the present invention is applied to an exhaust gas purifying apparatus for an automobile engine.
A bypass passage 5 through which exhaust gas flows when the engine is cold and an exhaust main passage 4 through which exhaust gas flows during engine warm-up are switched to a branch portion of an exhaust pipe 3 immediately after an exhaust manifold 2 of a gasoline engine 1 of an automobile. An exhaust gas switching valve device 6 (hereinafter simply referred to as a switching valve device) is provided.

A catalyst device with an electric heater (hereinafter abbreviated as EHC) 7 is provided in the bypass passage 5 as an early cleaning device. The EHC 7 carries a catalyst such as platinum or rhodium on a carrier formed of a heat-resistant metal such as ceramic or stainless steel, and
An electric heater is built in the catalyst carrier, and the catalyst is activated early by energizing the electric heater to generate heat.

The bypass flow passage 5 and the exhaust main flow passage 4 are EH
In the exhaust pipe 3 that merged again downstream of C7 and returned to one,
A main catalyst device 8 that serves as a main purification device of the exhaust gas purification device is provided. The main catalyst device 8 is configured by internally including a honeycomb carrier made of cordierite carrying a three-way catalyst containing a noble metal such as platinum or rhodium as a main component. An exhaust gas temperature sensor 9 is provided downstream of the main catalyst device 8, and the exhaust temperature sensor 9 detects the exhaust gas temperature of the main catalyst device 8 to monitor the active state of the main catalyst device 8. . Then, the signal of the exhaust temperature sensor 9 is taken into the control device 11, and the control device 11 turns on / off the solenoid valve 12 and the EHC 7.
Is determined. Here, the solenoid valve 12
Is a normally closed type when not energized.

As described above, the EHC 7 is the main catalyst device 8
In comparison with the above, the exhaust gas is located on the upstream side of the exhaust gas flow, and the exhaust gas having a temperature higher than the temperature of the exhaust gas flowing into the main catalyst device 8 is configured to flow. The control device 11 inputs operating conditions of the engine 1 (engine speed, intake air flow rate, intake pipe negative pressure, engine water temperature, oxygen concentration in exhaust gas, air-fuel ratio, etc.), and the solenoid valve 12 is input according to the conditions.
Alternatively, ON / OFF of the EHC 7 may be controlled.

The pipe 50 forming the bypass flow passage 5 and the pipe 40 forming the exhaust main flow passage 4 are both made of stainless steel. Next, the specific configuration of the switching valve device 6 will be described in more detail with reference to FIGS. FIG. 2 is a cross-sectional view of the switching valve device 6, and the solid line state of FIG. 2 shows a state in which the bypass flow path 5 is fully closed and the exhaust main flow path 4 is open, and the state of the two-dot chain line is It shows a state in which the exhaust main flow path 4 is fully closed and the bypass flow path 5 is open.

Reference numeral 60 denotes a disc-shaped stainless steel valve plate (valve body) of the switching valve device 6, and this valve plate 6
At the center of 0, one end of a stainless steel first arm (connecting member) 61 press-formed in a U-shape is welded via a stainless shaft 62. As shown in FIG. 2, the shape of the welded portion of the first arm 61 and the shaft 62 of the first arm 61 is such that the first arm 61 is perpendicular to the shaft 62 (the first arm 61 is parallel to the valve plate 60). So that the right-angled bending portion is formed.

Ribs 61a are formed at the right-angled bent portions to increase the rigidity of the first arm 61, and ribs 61b and 61c are similarly formed at the other right-angled bent portions.
Are formed. Here, the valve plate 60 and the first
The arm 61 may be directly welded without the shaft 62. The other end of the first arm 61 is welded after being inserted into a square hole 63b formed in a stainless steel driven shaft 63. The driven shaft 63 is made of a stainless steel housing as shown in FIG. It is accommodated in 64 and is rotatably supported in contact with the inner wall surface of the shaft housing 64 by ridges 63c formed at both ends of the driven shaft 63 over the entire circumference.

A groove 63 is formed at one end of the driven shaft 63.
a is formed, and the flat surface portion 65a of the ceramic main shaft 65 is fitted in the groove 63a. The main shaft 65 is rotatably supported by a ceramic slide bearing 66, and the slide bearing 66 is inserted into a shaft housing 64. Also, the main shaft 65-2
A groove 65b is formed at the end portion on the surface width portion 65a side, and a retaining ring 65c made of stainless steel is attached to the groove 65b.

A stainless washer 67 is inserted into the main shaft 65 and is welded to the stainless steel pipe 50 forming the shaft housing 64 and the bypass flow passage 5 on the opposite side of the two-face width portion 65a. ing. This allows
The slide bearing 66 and the main shaft 65 are prevented from falling off, and the shaft housing 64 is fixed to the pipe 50. The first arm 61, the shaft housing 64, and the driven shaft 6 described above.
3, the main shaft 65 and the slide bearing 66 form a valve operating mechanism 69 for driving the valve plate 60. The valve operating mechanism 69 is arranged in the bypass flow passage 5 as shown in FIG. .

The end of the main shaft 65 on the washer 67 side is exposed to the outside of the bypass passage 5, as shown in FIG. 3, and a semi-circular cutout is formed in this exposed portion. A cutout portion 65d is provided. As shown by the broken line in FIG. 2, one end side of a second arm 68 forming a crank mechanism is inserted into the cutout portion 65d, and is attached to a groove 65e (see FIG. 3) formed in the cutout portion 65d. The retaining ring (not shown) prevents it from falling off.

On the other end side of the second arm 68, as shown in FIG.
The shaft 68a is provided as shown in FIG.
The second arm 68 and the rod 101 of the actuator 100 that drives the valve plate 60 are rotatably connected by a. The drive unit of the actuator 100 is composed of a diaphragm 102 made of rubber or metal, a coil spring 103 for return, and a casing 104 for housing these. The space 104a formed by the casing 104 and the diaphragm 102 is
As shown in FIG. 1, the intake manifold 13 of the engine 1 is communicated with a pipe 12 a and a solenoid valve 12.

Further, in FIG. 2, reference numeral 41 denotes a stainless steel main flow path side valve seat which is in pressure contact with the valve plate 60 when the exhaust main flow path 4 is closed. It passes through the exhaust main flow path side valve opening 42 provided in the main flow path side valve seat 41. Similarly,
Reference numeral 51 denotes a stainless steel bypass flow path side valve seat with which the valve plate 60 is pressed when the bypass flow path 5 is closed. All exhaust gas flowing through the bypass flow path 5 is provided in the bypass flow path side valve seat 51. It passes through the bypass flow path side valve opening 52. The opening area of the bypass passage-side valve opening 52 is smaller than the opening area of the exhaust main passage-side valve opening 42.
Has an opening area of 30 of the opening area of the exhaust main flow path side valve opening 42.
% To 80% is desirable.

Incidentally, in this embodiment, the opening diameter of the bypass passage side valve opening 52 is about 34 mm (the opening area is about 90 mm).
7 mm ² ), the diameter of the opening of the exhaust main flow path side valve port 42 is about 5
4 mm (open area about 2289mm ^2), the opening area of the bypass flow valve port 52 is about 39% open area of the exhaust main flow path side valve port 42. The main flow path side valve seat 41 and the bypass flow path side valve seat 51 are welded to the pipe 40 and the pipe 50, respectively. Then, the dimension R from the center of the bypass flow passage side valve opening 52 and the exhaust main flow passage side valve opening 42 to the rotation center of the driven shaft 63 (main shaft 65)
Is the radius of rotation r from the center of rotation of the driven shaft 63 (main shaft 65) to the joint between the valve plate 60 and the first arm 61.
Matches.

Next, the operation of this embodiment will be described. When the control device 11 determines that the catalyst of the main catalyst device 8 has not reached the catalyst activation temperature by the signal from the exhaust temperature sensor 9 when the engine is cold immediately after the engine is started, the control device 11 The solenoid valve 12 and the EHC 7 are energized. As a result, the solenoid valve 12 opens, and the space 104a of the actuator 100 and the intake manifold 13 of the engine 1 communicate with each other via the pipe 12a. Then, the suction negative pressure of the engine causes the diaphragm 102 to move so as to reduce the volume of the space 104a, and the rod 101 moves in conjunction with this. Further, the second arm 68 and the first arm 61 rotate to bring the valve plate 60 into contact with the main flow path side valve seat 41 to close the exhaust main flow path side valve opening 42, as shown by the chain double-dashed line in FIG. .

Therefore, as shown in FIG. 1, the exhaust gas flows through the bypass flow path 5, is purified by the EHC 7, and is discharged into the atmosphere from the muffler (not shown) via the main catalyst device 8. At this time, the exhaust gas that has passed through the EHC 7 is further heated by the heater and reaction of the EHC 7, passes through the main catalyst device 8 from the bypass flow passage 5 through the exhaust main flow passage 4, and warms up the catalyst of the main catalyst device 8. .

The above-described operation is performed until the temperature of the catalyst of the main catalyst device 8 reaches the catalyst activation temperature. Here, the temperature of the catalyst is detected by the exhaust temperature sensor 9 provided downstream of the main catalyst device 8. By the way, since the opening area of the bypass flow passage side valve opening 52 is smaller than that of the exhaust main flow passage side valve opening 42, the exhaust pressure loss becomes larger than that in the case where the exhaust gas flows in the exhaust main flow passage 4. However, since it is a low load operation immediately after the engine starts, the amount of exhaust gas is small,
The decrease in engine output due to exhaust pressure loss is small.

When the temperature of the catalyst in the main catalyst device 8 reaches the catalyst activation temperature, the control device 11 shuts off the power supply to the solenoid valve 12 and the EHC 7. As a result, the electromagnetic valve 12 is closed and the supply of negative pressure to the actuator 100 is cut off, so that the diaphragm 102 moves so that the volume of the space 104a expands due to the restoring force of the coil spring 103. Then, in conjunction with this, the rod 101 moves, the second arm 68, the first arm 61 and the valve plate 60 rotate, and as shown by the solid line in FIG. And the bypass flow path side valve opening 52 is closed.

Therefore, all the exhaust gas passes through the exhaust main flow path 4, is purified by the main catalyst device 8, and is then discharged into the atmosphere through a muffler (not shown). Next, features of the present embodiment will be described. When the temperature of the catalyst of the main catalyst device 8 has not reached the catalyst activation temperature immediately after the engine is started, the exhaust gas is introduced into the bypass passage 5 in which the EHC 7 heated by the heater and reached the catalyst activation temperature is arranged. Since the switching valve device 6 is controlled so that the exhaust gas flows, the exhaust gas can be purified with high purification efficiency even immediately after the engine is started.

After the engine is warmed up, the main catalyst device 8 purifies the exhaust gas, so that the exhaust gas can be purified under a wide range of engine operating conditions from immediately after the engine is started to after the engine is warmed up. Also, as mentioned above,
Immediately after the engine is started, the exhaust gas can be purified by the EHC 7. Therefore, in order to quickly raise the catalyst temperature of the main catalyst device 8 to the catalyst activation temperature, the exhaust gas can be exhausted without disposing the main catalyst device 8 near the engine. The gas can be purified. Therefore, since the catalyst of the main catalyst device 8 is not exposed to high temperature conditions, thermal deterioration of the catalyst can be suppressed, and high exhaust gas purification efficiency can be maintained for a long time.

Further, after the engine is warmed up, the bypass passage 5 is closed and the high temperature exhaust gas does not flow in the bypass passage 5, so that the heat deterioration of the catalyst of the EHC 7 due to heat can be suppressed. Further, the first arm 61, the shaft housing 64, the driven shaft 63, the main shaft 65 and the slide bearing 66.
Since the valve operating mechanism 69 consisting of is arranged in the bypass flow passage 5, the bypass flow passage 5 is not provided after the engine is warmed up.
When closed, these valve actuation mechanisms 69 are not directly exposed to the hot exhaust gases. Therefore, the valve operating mechanism 69
Of the driven shaft 63 and the main shaft 65 due to thermal deformation and thermal strain, and malfunctions due to twisting of the driven shaft 63 and the main shaft 65 can be suppressed.

By the way, immediately after the engine is started, the first arm 61, the shaft housing 64, the driven shaft 63, and the main shaft 6 are provided.
5 and the slide bearing 66 are directly exposed to the exhaust gas, but immediately after the engine is started, the temperature of the exhaust gas is low, and therefore, these members do not deteriorate due to heat. Further, since the opening area of the bypass flow passage side valve opening 52 is smaller than the opening area of the exhaust main flow passage side valve opening 42, the valve plate 6
The force acting on the bypass flow path 5 side of the valve plate 60 (the product of the working pressure on the bypass flow path 5 side and the opening area of the bypass flow path side valve opening 52) when 0 closes the bypass flow path side valve opening 52. And the force acting on the exhaust main flow passage 5 side (the product of the pressure acting on the exhaust main flow passage 5 side and the opening area of the bypass flow passage side valve opening 52) can be reduced.

Therefore, as described in the section of the problem to be solved by the invention, it is possible to suppress the chattering generated in the valve plate 60 due to the pressure imbalance acting on both front and rear surfaces of the valve plate 60. Further, since the unbalance amount of the force acting on the valve plate 60 can be reduced, the acting force of the actuator 100 pressing the valve plate 60 against the bypass flow path side valve seat 51 to correct the unbalance amount is reduced. can do. Therefore, the first arm 61, the shaft housing 64, the driven shaft 63, the main shaft 65 and the slide bearing 66.
Since the mechanical load such as the above becomes small, these and the actuator 100 can be downsized. And
In combination with the reduction of mechanical load and the effects of suppressing thermal deformation and thermal strain described above, it is possible to further suppress malfunctions due to twisting of the driven shaft 63 and the main shaft 65.

Incidentally, FIG. 4 shows the force required to press the valve plate 60 to prevent chattering when a pressure difference of maximum 0.2 kgf / cm ² is generated on both front and back surfaces of the valve plate 60, and the bypass flow. 6 is a graph showing the relationship with the diameter of the roadside valve opening 52. As is clear from FIG. 4, the smaller the diameter of the bypass passage-side valve opening 52, the smaller the force required to press the valve plate 60 to prevent chattering.

By the way, by appropriately selecting the length of the bypass flow passage 5, the phase difference of the pressure pulsation is set to 180 degrees,
A means of canceling pressure pulsation and suppressing chattering is conceivable.However, in this means, the frequency of pressure pulsation changes depending on the engine speed, so pressure pulsation is canceled out stably over a wide engine speed range to prevent chattering. It is difficult to control. However, according to the present embodiment, as described above, chattering can be suppressed regardless of the engine speed.

Further, by adjusting the inner diameter of the pipe 12a, the pressure change speed of the space 104a can be adjusted. Therefore, by setting the inner diameter of the pipe 12a to an appropriate size, a rapid pressure change can be suppressed, and the impact force acting on the valve plate 60 or the like can be reduced when the switching valve device is activated. Incidentally, in this embodiment, the inner diameter is about 1 mm.

(Second Embodiment) In this embodiment, the coupling position between the valve plate 60 and the first arm 61 is eccentric. The structure of the driven shaft 6 is as shown in FIG.
The dimension R from the center of rotation of 3 to the center of the bypass passage side valve opening 52 is smaller than the radius of rotation r from the center of rotation of the driven shaft 63 (main shaft 65) to the joint between the valve plate 60 and the first arm 61. It was done.

Next, the features of this embodiment will be described. The dimension R from the rotation center of the driven shaft 63 to the center of the bypass flow path side valve opening 52 is determined by measuring the rotation center of the driven shaft 63 to the valve plate 6.
Since it is smaller than the turning radius r up to the connecting portion between 0 and the first arm 61, the bypass passage side valve port 52 can be brought close to the rotation center of the driven shaft 63. Therefore, the switching valve device 6 can be downsized.

Further, the bypass passage side valve port 52 is connected to the driven shaft 6
3, the distance between the first arm 61 and the inner edge of the bypass flow passage side valve opening 52 becomes large as shown in part B of FIG. 5, so that the first arm 61 and the bypass flow passage side valve seat 51 are provided. You can avoid interference with.
Therefore, since the degree of freedom in designing the first arm 61 is increased, the cost of the first arm 61 and the pipe 50 can be reduced, and the cost of the switching valve device 6 can be reduced.

By the way, in the above-mentioned embodiment, the switching valve device 6 is arranged at the branch portion of the bypass flow passage 5 and the exhaust main flow passage 4, but the switching valve device 6 may be arranged at the confluence portion of both the flow passages. The present invention can be implemented. Further, the present invention can be implemented as a switching valve device by arranging a valve device including an actuator and a valve plate, etc., independently in each of the bypass flow passage 5 and the exhaust main flow passage 4.

In the above embodiment, the exhaust main flow path 4 and the bypass flow path 5 are switched and opened via the main flow path side valve seat 41 and the bypass flow path side valve seat 51. However, these valve seats are not provided. The present invention can be implemented by directly switching and opening the exhaust main flow path 4 and the bypass flow path 5. Further, the exhaust main flow path side valve opening 42
The shape of the opening of the bypass flow path side valve opening 52 is not limited to a circular shape, and may be another shape such as a rectangle.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an exhaust gas purification device using a switching valve device according to a first embodiment of the present invention.

FIG. 2 is a half cross-sectional view of the switching valve device according to the present embodiment.

FIG. 3 is a sectional view taken along line AA of FIG. 2;

FIG. 4 is a graph showing the relationship between the pressing force of the valve plate and the diameter of the bypass passage side valve opening.

FIG. 5 is a half sectional view of a switching valve device according to a second embodiment of the present invention.

FIG. 6 is a schematic diagram illustrating a cause of chattering of a valve plate.

[Explanation of symbols]

1 ... Engine, 2 ... Exhaust manifold, 3 ... Exhaust pipe, 4 ...
Exhaust main flow passage, 5 ... Bypass flow passage, 6 ... Exhaust gas switching valve device, 7 ... Catalyst device (EHC) with electric heater, 8 ... Main catalyst device, 9 ... Exhaust temperature sensor, 11 ... Control device, 12 ...
Solenoid valve, 40, 50 ... Pipe, 41 ... Main flow passage side valve seat, 42 ... Exhaust main flow passage side valve port, 51 ... Bypass flow passage side valve seat, 52 ... Bypass flow passage side valve port, 60 ... Valve plate (valve body), 61 ... First arm (connecting member), 6
2 ... Shaft, 61a, 61b, 61c ... Rib, 63 ... Driven shaft, 63a ... Groove, 63b ... Square hole, 64 ... Shaft housing,
65 ... Spindle, 65a ... 2 face width, 65b ... Groove, 65c ... Retaining ring, 66 ... Sliding bearing, 67 ... Washer, 68 ... Second
Arm, 69 ... Valve operating mechanism, 100 ... Actuator,
101 ... Rod, 102 ... Diaphragm, 103 ... Coil spring, 104 ... Casing.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masakazu Tanaka 1-1-1, Showa-cho, Kariya city, Aichi Prefecture NIDEC CORPORATION

Claims (5)

[Claims] An exhaust gas switching valve device (6) for switching between a bypass flow passage (5) through which exhaust gas flows when the engine is cold and an exhaust main flow passage (4) through which exhaust gas flows when the engine is warmed up. And a bypass passage-side valve opening (52) through which exhaust gas flowing in the bypass passage (5) passes, the exhaust main passage (4) being provided so as to communicate with the bypass passage (5). An exhaust main flow passage side valve opening (42) provided so as to communicate with each other, through which exhaust gas flowing in the exhaust main flow passage (4) passes, the bypass flow passage side valve opening (52) and the exhaust main flow passage side valve opening (42) ) And an actuator (100) for driving the valve body (60)
The exhaust gas switching valve device, wherein the opening area of the bypass flow passage side valve opening (52) is smaller than the opening area of the exhaust main flow passage side valve opening (42). 2. The bypass flow passage side valve opening (52) and the exhaust main flow passage side valve opening (42) are provided at a connecting portion of the bypass flow passage (5) and the exhaust main flow passage (4), A rotary shaft (63, 65) which is provided at a connecting portion between the bypass flow passage (5) and the exhaust main flow passage (4) and is rotated by the movement of the actuator (100), and the rotary shaft (63, 65). Bearings that support the shaft (64, 6
6) and a connecting member (61) whose one end is connected to the rotating shafts (63, 65) and the other end is connected to the valve body (60), and these rotating shafts (63, 65) and bearings are provided. The exhaust gas switching valve device according to claim 1, wherein the parts (64, 66) and the connecting member (61) are both arranged in the bypass flow passage (5). 3. The dimension (R) from the center of rotation of the rotary shafts (63, 65) to the center of the bypass passage side valve opening (52) is measured from the center of rotation of the rotary shafts (63, 65) to the valve body. The exhaust gas switching valve device according to claim 2, wherein the radius of gyration (r) up to the connecting portion between the (60) and the connecting member (61) is smaller. 4. The opening area of the bypass flow passage side valve opening (52) is 3 times the opening area of the exhaust main flow passage side valve opening (42).
It is 0% -80%, It is characterized by the above-mentioned.
The switching valve device for exhaust gas according to any one of 1. 5. Arranged in the exhaust pipe (3) of the engine,
A catalyst device (8) for purifying exhaust gas harmful components, a bypass channel (5) provided in the exhaust pipe (3), and a catalyst device (8) arranged in the bypass channel (5). An early purification device (7) located upstream of the exhaust gas flow for purifying exhaust gas harmful components, and provided in the exhaust pipe (3) in parallel with the bypass flow passage (5) to provide the early purification. An exhaust main flow path (4) that forms a flow of exhaust gas that does not pass through the device (7), and switches the flow of exhaust gas to either one of the bypass flow path (5) and the exhaust main flow path (4). An exhaust gas switching valve device according to any one of claims 1 to 4, and an actuator (100) for the exhaust gas switching valve device.
The exhaust gas switching valve so that exhaust gas is circulated to the bypass flow passage (5) when the engine is cold and exhaust gas is circulated to the exhaust main flow passage (4) when the engine is warmed up. An exhaust gas purification device comprising: a control means (11) for controlling the device.