JPH066186Y2 - Exhaust gas purification device for diesel engine - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to an exhaust emission control device provided in an exhaust system of a diesel engine for collecting particulates in exhaust gas.

[Conventional technology]

This exhaust emission control device has, for example, a Hankham filter,
When the trapped amount of particulates exceeds a predetermined value, the particulates are burned to regenerate the filter. Japanese Unexamined Patent Publication No. 61-223215 discloses a conventional exhaust gas purification device, in which an electric heater is provided in a portion close to one end of a filter, and first and second bypass pipes bypassing the filter. Are provided, and five valves are provided to control the flow of exhaust gas in these bypass pipes and filters. When collecting particulates, the exhaust gas does not pass through the first and second bypass pipes but flows through the filter and then passes through the electric heater to be discharged into the atmosphere. When the filter is regenerated, in order to prevent the filter from being melted and damaged, the exhaust gas flows from the electric heater side into the filter through the first bypass pipe, and is discharged into the atmosphere through the second bypass pipe. Is energized and the particulates ignite and burn.

[Problems to be solved by the device]

However, the above-mentioned conventional device is provided with the five valves as described above in order to reverse the flow direction of the exhaust gas in the filter at the time of collecting the particulates and at the time of regenerating the filter. It is driven to open and close by the actuator. That is, the conventional device has a problem that a large number of valves and actuators are required, the control is complicated, and the configuration is complicated, so that the device cannot be easily mounted on a vehicle.

[Means for Solving the Problems]

In the exhaust gas purifying apparatus according to the present invention, the first and second bypass pipes are connected to a connecting portion located upstream of the filter of the exhaust pipe in close proximity to each other, and a single switching valve is provided in the connecting portion. The switching valve closes the first and second bypass pipes when collecting particulates, and partitions the exhaust pipe into upstream and downstream sides when the filter is regenerated and the first and second bypass pipes are provided. Open the bypass pipe.

〔Example〕

 The present invention will be described below with reference to illustrated embodiments.

1 and 2 show an exhaust emission control device according to an embodiment of the present invention. The filter 11 is provided in the middle of the exhaust pipe,
Collect particulates in the exhaust gas. The exhaust pipe has an upstream exhaust pipe 21, an upstream connecting portion 22, a downstream connecting portion 23, and a downstream exhaust pipe 24, and the filter 11 has an upstream connecting portion 22.
And is housed in a housing 12 provided between the downstream connecting portion 23. The upstream exhaust pipe 21 is connected to the upstream connecting portion 22 and communicates with an exhaust manifold (not shown). The downstream exhaust pipe 24 is connected to the downstream connecting portion 23 and communicates with the atmosphere.

The upstream and downstream portions of the exhaust pipe with respect to the filter 11 are connected by first and second bypass pipes 31 and 32. As shown in FIG. 3, the first and second bypass pipes 31 and 32 are formed by partitioning groove-shaped members 33 and 34 having a semicircular cross section by a partition plate 35, and the upstream connecting portion 22 and the downstream connecting portion 23. Connected to.
Therefore, the first and second bypass pipes 31 and 32 are connected to the upstream connecting portion 22 and the downstream connecting portion 23 in close proximity to each other. Although the first bypass pipe 31 is located below the second bypass pipe 32 on the upstream connecting portion 22 side, the downstream connecting portion 23
On the side, the first bypass pipe 31 is located above the second bypass pipe 32. That is, the first and second bypass pipes 3
1,32 are twisted at the intermediate portion 36 thereof.

The upstream connecting portion 22 has a joint portion 25 extending downward in the drawing. The joint portion 25 has a partition wall 26 to form first and second openings.
The first and second opening portions 27 and 28 are divided into 27 and 28, and communicate with the first and second bypass pipes 31 and 32, respectively. A switching valve 41 is provided at the upstream connecting portion 22. The switching valve 41 is
It is rotatably supported by a pin 42 arranged above the partition wall 26, and at the first position shown in FIG. 1, the first and second openings 27, 28, that is, the first and second bypass pipes 31,
32 is closed and the upstream exhaust pipe 21 is connected to the housing 12
To open the first and second bypass pipes 31 and 32, and to disconnect the upstream exhaust pipe 21 and the housing 12 at the second position shown in FIG. The switching valve 41 is connected to an actuator 44 via a rod 43, and is opened / closed by the actuator 44. The actuator 44 is of a conventionally known diaphragm type and operates by selectively guiding atmospheric pressure and negative pressure by a negative pressure control valve 45.

4 to 7 show the upstream connecting portion 22 and the switching valve 41.
The switching valve 41 is a disc-shaped butterfly valve, which closes the first and second openings 27, 28 in the horizontal position, that is, the first position, as shown in FIGS. The horizontal passage 29 formed in the portion 22 is opened. The horizontal passage 29 has a semicircular cross section as is clear from FIG. The partition wall 26 has a semicircular cutout 37 so that the switching valve 41 can open the first and second openings 27, 28 and close the horizontal passage 29 in the vertical position, that is, the second position. .

The downstream connecting portion 23 has a joint portion 51 extending downward as shown in FIGS. 1 and 2. The joint portion 51 is partitioned by the partition wall 52 into first and second opening portions 53, 54, and these opening portions 53, 54 are respectively the first and second bypass pipes 31, 32.
Communicate with. The partition wall 52 is the partition wall 26 in the upstream connecting portion 22.
As described above, the partition wall 52 does not have a semicircular cutout, and the tip end of the partition wall 52 extends to the upper end portion of the horizontal passage 55 in the downstream connecting portion 23. The flow path control valve 61 is rotatably supported by the pin 62,
In the first position shown in FIG.
The second openings 53, 54 and the horizontal passage 55 are opened. Further, the flow path control valve 61 is in the vertical state at the second position shown in FIG. 2, the upper edge portion thereof is in close contact with the upper inner wall of the horizontal passage 55, and the lower edge portion thereof is the first opening portion 53 of the partition wall 52. Located on the side. The flow path control valve 61 is connected to a diaphragm type actuator 64 via a rod 63. The actuator 64 operates by selectively guiding the atmospheric pressure and the negative pressure by the negative pressure control valve 65 to open and close the flow path control valve 61.

An electric heater 71 is provided inside the housing 12 and on the downstream side of the filter 11. The electric heater 71 is the relay 7
It is connected to the battery 73 through 2, and when the filter 11 is regenerated, it is energized to generate heat and ignite and burn particulates on the filter 11. The regeneration timing of the filter 11, that is, the amount of collected particulates is determined by comparing the reference pressure obtained from the engine load and the engine speed with the exhaust pipe internal pressure, and the regeneration control is performed by an electronic control unit equipped with a microcomputer ( ECU) 74.
Therefore, the ECU 74 is connected to an accelerator sensor 75 that detects the engine load, that is, the accelerator opening, a rotation speed sensor 76 that detects the engine speed, and a pressure sensor 77 that detects the exhaust pipe internal pressure.

Next, the operation of this embodiment will be described.

At the time of collecting particulates, the switching valve 41 and the flow path control valve 61 are in the first positions as shown in FIG. That is, the switching valve 41 includes the first and second bypass pipes 3
1, 32 are closed, and the control valve 61 is the first and second bypass pipes.
Fully open 31,32 and horizontal passage 55. Therefore, the exhaust gas flowing through the upstream exhaust pipe 21 flows into the housing 12 through the upstream connecting pipe 22, passes through the filter 11 and the heater 71 in this order, and flows to the downstream connecting portion 23. Is released to. During this time, the particulates contained in the exhaust gas are collected by the filter 11.

When the filter 11 is regenerated, the switching valve 41 and the flow path control valve 6
1 are in their respective second positions as shown in FIG.
That is, the switching valve 41 partitions the horizontal passage 29 into an upstream side and a downstream side and opens the first and second bypass pipes 31 and 32. Further, the control valve 61 closes the upper portion of the horizontal passage 55 and divides the end portion of the first opening portion 53 into a portion on the housing 12 side and a portion on the downstream exhaust pipe 24 side. Therefore, the exhaust gas flows from the upstream exhaust pipe 21 to the first bypass pipe 31.
Flow into the first opening 53 of the downstream connecting portion 23,
It flows separately in the housing 12 side and the downstream exhaust pipe 24 side. The exhaust gas flowing into the housing 12 is heated by the heater 7
1, then passes through the filter 11 in this order, and then flows into the second bypass pipe 32 from the upstream connecting portion 22. Then, this exhaust gas is discharged into the atmosphere from the downstream exhaust pipe 24. At this time, the electric heater 71 is energized to generate heat, which causes the particulates on the filter to ignite and burn.

Thus, the first and second bypass pipes 31, 32 are connected to the upstream connecting pipe 22 in close proximity to each other, and a single switching valve 41 is provided at this connecting portion. Also in the downstream connecting pipe 23, similarly, the first and second bypass pipes 31 and 32 are connected to the connecting pipe 23 in close proximity to each other, and a single flow path control valve 61 is provided in this connecting portion. There is. Therefore, the flow direction of the exhaust gas is reversed at the time of particulate collection and filter regeneration, so that the switching valve 4 is provided in the exhaust system.
1 and the control valve 61 only, and the actuators 44 and 64 need only be provided corresponding to these valves, the number of actuators is smaller than before, and the structure of the exhaust gas purification device is very simple. And simplifies the control of the valve mechanism.

The flow path control valve 61 may be in contact with the partition wall 52 at the second position and may have a notch or a hole in the contact portion.

FIG. 8 shows another embodiment of the upstream connecting portion 22 and the switching valve 41. In the upstream connecting portion 22, the upstream exhaust pipe 21
Cylindrical portion 91 and housing 1 connected to (FIGS. 1 and 2)
2 (FIGS. 1 and 2) are perpendicular to each other, and the first opening 27 communicating with the first bypass pipe 31 is the second opening passing through the second bypass pipe 32. Opening 2
It has a flow passage area larger than eight. Switch valve 41 is pin 4
It is rotatably supported by 2, and closes the first and second openings 27, 28 at a first position shown by a solid line, and the first opening 27 at an upstream side at a second position shown by a broken line.
Further, the second opening 28 is communicated with the downstream side.

The same effect as that of the embodiment shown in FIGS. 1 to 7 can be obtained by the switching valve shown in FIG.

[Effect of device]

As described above, according to the present invention, the structure of the valve mechanism for controlling the opening and closing of the first and second bypass pipes is simplified, the device is downsized, and the valve mechanism can be easily mounted on a vehicle. Easy to control.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an embodiment of the present invention when collecting particulates, FIG. 2 is a cross-sectional view of an embodiment of the device during filter regeneration, and FIG. 3 is a cross-section taken along line III-III of FIG. Fig. 4, Fig. 4 is a perspective view showing the upstream connecting portion, Fig. 5 is a front view showing the upstream connecting portion, Fig. 6 is a bottom view showing the upstream connecting portion, and Fig. 7 is a line VII-VII in Fig. 5. FIG. 8 is a sectional view showing another embodiment of the upstream connecting portion.

Claims (1)

[Scope of utility model registration request] 1. A heater is provided on the downstream side of a filter provided in the middle of an exhaust pipe, and a portion of the exhaust pipe upstream and downstream of the filter is connected by first and second bypass pipes. When collecting the particulates of the filter, the first and second bypass pipes are closed, and exhaust gas passes through the filter and the heater in this order and is discharged into the atmosphere. When the filter is regenerated, the first and second bypass pipes are discharged. 2 In the exhaust emission control device for a diesel engine, wherein the bypass pipe is opened and the exhaust gas passes through the first bypass pipe, the heater, the filter, and the second bypass pipe in this order, and is discharged into the atmosphere. The pipes are connected to a connecting portion located upstream of the filter of the exhaust pipe in close proximity to each other, and a single switching valve is provided in the connecting portion, and the switching valve is a partition valve. Time rate collection, the first and second
An exhaust emission control device for a diesel engine, wherein the bypass pipe is closed, the exhaust pipe is partitioned into an upstream side and a downstream side, and the first and second bypass pipes are opened during filter regeneration.