JP2957865B2 - Backwashing particulate collection equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a honeycomb filter for collecting particulates in exhaust gas of an engine, which is forcibly blown with compressed air from the downstream side of the exhaust gas to remove the collected particulates from the filter. The present invention relates to an apparatus for performing the above.

[0002]

2. Description of the Related Art Heretofore, as a particulate trapping device of this kind, a heat-resistant filter for trapping particulates in exhaust gas in an exhaust gas passage of an engine and a particulate trapped in the filter are burned. A particulate purification device for an internal combustion engine, comprising a heater, a small hole having at least one end open to the outside in the filter near the exhaust gas inflow side end face of the filter, and a heater embedded in the small hole is disclosed. (Japanese Unexamined Patent Publication No. 57-19830)
9). In this purifying device, radiation loss of heat of the heater can be prevented, and heat of the heater acts intensively on particulates collected by a filter surrounding the heater.
As a result, the soot in the particulates can be heated and burned with relatively little power consumption. Further, the combustion heat of the soot around the heater is transmitted to the downstream side of the filter, so that the soot in the entire filter is burned and purified.

[0003]

However, in the above-described conventional apparatus for purifying particulates of an internal combustion engine, the filter becomes extremely hot due to the heat generated by the heater, so that the life of the filter may be shortened. Further, in the above-mentioned conventional particle purifying apparatus,
Because the coefficient of thermal expansion of the filter and the collector containing this filter are different, the sealing structure of the filter becomes complicated,
There is a risk of defective sealing.

[0004] It is an object of the present invention to provide a backwashing type particulate collection device capable of removing particulates collected by a honeycomb filter in a short time and improving the durability of the honeycomb filter. is there.

[0005]

A configuration of the present invention for achieving the above object will be described with reference to FIG. 1 corresponding to an embodiment. The backwash type particulate trapping device of the present invention includes a filter chamber 12a provided in the exhaust pipe 11 connected to the exhaust manifold of the engine and containing the honeycomb filter 13 and a filter chamber 12a on the exhaust gas upstream side of the filter 13. A particulate collector 12 having a soot storage chamber 12b provided below, and a filter chamber 12a provided in the downstream exhaust pipe 11b or the collector 12 downstream of the filter 13 for exhaust gas downstream of the filter 13 when the filter 13 is backwashed. An air injection port 16 for injecting compressed air, and one end connected to an upstream exhaust pipe 11a upstream of the filter 13 on the exhaust gas side and another end connected to a downstream exhaust pipe 11b downstream of the air injection port 16 on the exhaust gas side. Pipe 24 that bypasses the vessel 13, a soot incinerator 26 provided in the middle of the bypass pipe 24, and one end connected to the soot accumulation chamber 12 b. The other end soot guide tube 27 connected to the upstream side bypass pipe 24a of the exhaust gas upstream side of the soot incinerator 26, and one end of the connecting portion of the bypass pipe 24 collector 12
First on-off valve 4 provided in the upstream exhaust pipe 11a between
1 and a second on-off valve 4 provided in the downstream exhaust pipe 11b between the air injection port 16 and the connection portion at the other end of the bypass pipe 24.
2 and a third on-off valve 41 provided in the upstream bypass pipe 24a on the exhaust gas upstream side from the connection portion at the other end of the soot guide pipe 27.
When the filter 13 collects the particulates 14, the first on-off valve 41 and the second on-off valve 42 are opened to close the third on-off valve 41, and when the filter 13 is backwashed, the first on-off valve 4 is closed.
Valve drive means 29 and 32 for closing the first and second on-off valves 42 and opening the third on-off valve 41 are provided.

[0006]

When the honeycomb filter 13 is backwashed, the valve driving means 29 and 32 are operated by the first on-off valve 41 and the second on-off valve 4.
2 is opened and the third on-off valve 41 is closed. In this state, compressed air is injected from the air injection port 16 into the filter chamber 12a for a short time. As a result, the particulates 14 collected by the filter 13 are removed by the injected compressed air and are deposited in the soot accumulation chamber 12b. When the backwash is completed, the valve driving means 29, 32 closes the first on-off valve 41 and the second on-off valve 42 and opens the third on-off valve 41. In this state, the soot guide pipe 27 and the bypass pipe 24
A small amount of exhaust gas flows toward the downstream exhaust pipe 11b through the exhaust pipe, and the particulates 14 in the soot storage chamber 12b pass through the soot guide pipe 27 and the upstream bypass pipe 24a to the soot incinerator 26 due to the exhaust gas flow. The soot in the particulates 14 is conveyed and incinerated by the soot incinerator 26.

[0007]

Next, an embodiment of the present invention will be described in detail with reference to the drawings. As shown in FIGS. 1 and 2, a diesel engine is a vehicle engine. An exhaust pipe 11 is connected to an exhaust manifold of the engine, and a particulate collector 12 is provided in the exhaust pipe 11. . Inside the collector 12, there are formed a filter chamber 12a in which the honeycomb filter 13 is accommodated, and a soot storage chamber 12b provided below the filter chamber 12a on the exhaust gas upstream side of the filter 13. The soot storage chamber 12b communicates with the filter chamber 12a on the exhaust gas upstream side of the filter 13. The honeycomb filter 13 extends in the direction of the exhaust gas flow, and alternately plugs a plurality of partition walls 13a provided in parallel with each other at a predetermined interval in a direction orthogonal to the exhaust gas flow, and an inlet and an outlet of the exhaust gas. And a stopper 13b. The partition 13a is formed of a porous heat-resistant ceramic material, and the particulates 14 are trapped when the exhaust gas passes through the partition 13a.

The exhaust pipe 11 has one end connected to the exhaust manifold and the other end connected to the exhaust gas inlet of the collector 12, and one end connected to the exhaust gas outlet of the collector 12. And a downstream exhaust pipe 11b. The upstream exhaust pipe 11a guides the exhaust gas of the engine into the collector 12, and the downstream exhaust pipe 11b guides the exhaust gas passing through the filter chamber 12a to the atmosphere. An air injection port 16 is provided in the collector 12 on the exhaust gas downstream side of the filter 13,
One end of a backwash air pipe 17 is connected to the air injection port 16. The other end of the backwash air pipe 17 is connected to an air tank 18, and a pulse valve 19 that can be fully opened instantaneously is provided in the middle of the backwash air pipe 17. The pulse valve 19 includes a diaphragm 19a and a seat valve 19b fixed to the lower surface of the diaphragm 19a.
And an outlet side chamber 19e. A compression coil spring 19f is built in the pressure regulating chamber 19d, and the spring 19f urges the seat valve 19b against the valve seat 19g to shut off the inlet-side chamber 19c and the outlet-side chamber 19e. Entrance side room 1
9c and the pressure regulating chamber 19d are connected by a pipe 23, and a first solenoid valve 21 for switching three ports and two positions is provided in the middle of the pipe 23.

When the first solenoid valve 21 is turned on, the pressure regulating chamber 19d
Because the compressed air inside is released to the atmosphere, the diaphragm 1
The force of the compressed air pushing up 9a overcomes the elastic force of the compression coil spring 19f to separate the seat valve 19b from the valve seat 19g, and the inlet side chamber 19c and the outlet side chamber 19e communicate. When the first solenoid valve 21 is turned off, the compressed air in the inlet side chamber 19c flows into the pressure regulating chamber 19d, so that the force of the compressed air pushing down the diaphragm 19a overcomes the force of the compressed air pushing up the diaphragm 19a and the seat valve 19b. Is seated on the valve seat 19g, so that the inlet-side chamber 19c and the outlet-side chamber 19e are shut off.

The exhaust pipe 11 is connected to a bypass pipe 24 that bypasses the collector 12. One end of the bypass pipe 24 is connected to the upstream exhaust pipe 11a, and the other end is connected to the air injection port 16a.
It is connected to the downstream exhaust pipe 11b on the downstream side of the exhaust gas.
A soot incinerator 26 is provided in the middle of the bypass pipe 24.
In this example, the soot incinerator 26 accommodates an oxidation catalyst 26b in which a heater 26a is wound around the peripheral surface. Oxidation catalyst 26b
(Not shown) has a monolithic carrier made of a heat-resistant Fe-Cr-Al alloy, and an alumina coat layer on which a catalytically active component (platinum, palladium, alloy of platinum and palladium, etc.) is supported. .

The soot storage chamber 12b and the bypass pipe 24 are connected by a soot guide pipe 27. One end of the soot guide tube 27 is connected to a lower portion of the soot storage chamber 12b, and the other end is connected to an upstream bypass pipe 24a on the exhaust gas upstream side of the soot incinerator 26. A first orifice 31 is formed at a connection portion at the other end of the soot guide tube 27. A slide valve 41 as a first opening / closing valve is provided in the upstream exhaust pipe 11a between the connection part at one end of the bypass pipe 24 and the collector 12, and the air injection port 16 is provided.
A second opening / closing valve 42 is provided in the downstream exhaust pipe 11 b between the second exhaust pipe 11 b and the connection portion at the other end of the bypass pipe 24, and the soot guide pipe 2
A slide valve 41, which is a third on-off valve, is provided in the upstream side bypass pipe 24a on the exhaust gas upstream side from the connection portion at the other end of 7.

The first and third on-off valves are 1 in this example.
The two plate-shaped slide valves 41 are also used. The slide valve 41 includes an upstream exhaust pipe 11a and an upstream bypass pipe 2
4a and a soot guide tube 27 extending in a direction perpendicular to the longitudinal direction thereof.
Is slidably inserted into The slide valve 41 has a second orifice 41a formed near the base end thereof, a through hole 41b formed substantially at the center, and a blocking part 41 formed at the tip end.
c. The base end of the slide valve 41 is a piston rod 29a of a spring return type air cylinder 29.
(FIG. 1), and the support shaft 42a of the second on-off valve 42 is connected to the output shaft 32a of the rotary actuator 32 of the spring return type. The air cylinder 29 and the rotary actuator 32 are connected to the air tank 18 via the second solenoid valve 22 that switches between three ports and two positions.

When the second solenoid valve 22 is turned on, the air tank 18 and the rotary actuator 32 are supplied to the air tank 18.
Are supplied, the piston rod 29a of the air cylinder 29 protrudes, and the rotary actuator 32 rotates the second on-off valve 42 in a direction to shut off the downstream exhaust pipe 11b (FIG. 1). When the second solenoid valve 22 is turned off, the air cylinder 29 and the rotary actuator 3
2, the compressed air in the air cylinder 29 is discharged, the piston rod 29a of the air cylinder 29 is retracted by the elastic force of a built-in spring (not shown), and the rotary actuator 32 is opened in the direction of opening the downstream exhaust pipe 11b by the elastic force of the built-in spring (not shown). The two on-off valves 42 are rotated (FIG. 2).

A pressure sensor 33 for detecting the pressure of the exhaust gas is provided in the exhaust pipe 11a on the upstream side of the exhaust gas from the connection portion at one end of the bypass pipe 24. Reference numeral 34 denotes a controller, to which a pressure sensor 33 is connected. The control output of the controller 34 is supplied to the heater 26a, the first solenoid valve 21 and the second solenoid valve 2 via a drive circuit 36.
2 is connected.

The operation of the thus constructed backwashing type particulate collecting apparatus will be described. Honeycomb filter 13
When a predetermined amount or more of the particulates 14 are collected,
The pressure sensor 33 detects the pressure of the exhaust gas equal to or more than a predetermined value,
The controller 34 turns on the second solenoid valve 22 based on this detection output. When the second solenoid valve 22 is turned on, the piston rod 29a of the air cylinder 29 protrudes, and the shut-off portion 41c of the slide valve 41 causes the upstream exhaust pipe 11a.
Is shut off, the upstream side bypass pipe 24a is opened by the through hole 41b of the slide valve 41, and the soot guide pipe 27 is narrowed by the second orifice 41a of the slide valve 41. When the second solenoid valve 22 is turned on, the rotary actuator 32 closes the second on-off valve 42 and shuts off the downstream exhaust pipe 11b (FIG. 1).

In this state, the controller 34 operates for 0.10 seconds to 0.
The first solenoid valve 21 is turned on for an extremely short time of 15 seconds. When the first solenoid valve 21 is turned on, the pulse valve 19 is fully opened instantaneously, and the compressed air in the air tank 18 is injected from the air injection port 16 into the filter chamber 12a. As a result,
The injected compressed air blows off the particulates 14 collected by the filter 13 and accumulates in the soot accumulation chamber 12b. The pressure of the compressed air also acts on the soot guide pipe 27 from the soot storage chamber 12b,
Since the pressure is reduced by the first orifice 31 and the second orifice 41a, the particulates 14 accumulated in the soot storage chamber 12b are guided to the bypass pipe 24 via the soot guide pipe 27 little by little.

When the second solenoid valve 22 is turned on, the exhaust gas of the engine passes through the bypass pipe 24. However, since the time for turning on the second solenoid valve 22 is short, the bypass pipe 2 is turned on.
The amount of exhaust gas passing through 4 is small. As a result, the soot contained in the particulates 14 in the exhaust gas
Incinerated by the oxidation catalyst 26b heated by 6a,
In addition, hydrocarbons, carbon monoxide, and the like contained in the exhaust gas are oxidized by the oxidation catalyst 26b into harmless carbon dioxide, water vapor, and the like. Therefore, the amount of the particulates 14 discharged to the atmosphere is extremely small.

When the controller 34 turns off the second solenoid valve 22 after the backwashing of the filter 13 is completed, the air cylinder 2
9 is retracted, and the upstream exhaust pipe 1
1a is opened, the upstream side bypass pipe 24a is shut off by the shutoff portion 41c of the slide valve 41, and the soot guide pipe 27 is opened by the through hole 41b of the slide valve 41. When the second solenoid valve 22 is turned off, the rotary actuator 32 opens the second on-off valve 42 to open the downstream exhaust pipe 11b (FIG. 2). In this state, the soot guide pipe 27, the first orifice 31, the second
A slight exhaust gas flow is generated through the orifice 41a, the bypass pipe 24, and the soot incinerator 26 toward the downstream exhaust pipe 11b. As a result, the particulates 14 in the soot storage chamber 12b are conveyed to the soot incinerator 26 by the exhaust gas flow, and soot in the particulates 14 is collected and incinerated by the oxidation catalyst 26b heated by the heater 26a.

In the above embodiment, the air injection port is provided in the collector downstream of the filter from the exhaust gas. However, this is merely an example, and the air injection port is provided in the downstream exhaust pipe downstream of the filter from the exhaust gas. Is also good. In this case, the connection portion at the other end of the second on-off valve and the bypass pipe is provided on the downstream exhaust pipe on the exhaust gas downstream side from the air injection port. In the above embodiment, the backwash timing of the filter is detected by the pressure sensor. However, at regular intervals, that is, when the vehicle travels for a certain period of time or for a certain distance, the first and third on-off valves are closed and the second on-off valve is closed. It may be configured to open. Further, in the above embodiment, the slide valve is configured to also serve as the first on-off valve and the third on-off valve.
The first opening / closing valve and the third opening / closing valve may be respectively constituted by different members. Further, in the above-described embodiment, the oxidation catalyst in which the heater is wound is used as the soot incinerator. However, the heater may be wound around a core other than the oxidation catalyst as long as the exhaust gas can pass therethrough and the soot can be collected and incinerated. . Further, in the above embodiment, the vehicle engine is used as the engine.
It may be a marine engine or another engine.

[0020]

As described above, according to the present invention, the soot storage chamber is provided below the filter chamber on the upstream side of the exhaust gas from the honeycomb filter, and air is supplied to the exhaust pipe or the collector downstream of the exhaust gas downstream of the filter. An injection port is provided, a soot incinerator is provided in the middle of a bypass pipe bypassing the collector, a soot guide pipe connects the soot accumulation chamber and the upstream bypass pipe, and a first on-off valve and a second
Since the on-off valve and the third on-off valve are configured to be driven by the valve drive means, the first on-off valve and the second on-off valve are closed by the valve drive means when the filter is backwashed, and the third on-off valve is opened. Open,
By injecting compressed air from the air injection port in this state, the particulates collected by the honeycomb filter can be removed in a short time. In addition, compared to a conventional particulate purification device for an internal combustion engine, the life of the filter is shortened due to the heat generated by the heater, or a seal failure occurs due to a difference in thermal expansion coefficient between the filter and a collector containing the filter. In the present invention, the soot incinerator for incinerating soot is provided separately from the filter, so that the durability of the filter can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional configuration view showing a state in which a honeycomb filter of a backwashing type particulate collecting apparatus according to an embodiment of the present invention is backwashed.

FIG. 2 is a cross-sectional configuration diagram corresponding to FIG. 1, showing a state when particulates are collected by the honeycomb filter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Exhaust pipe 11a Upstream exhaust pipe 11b Downstream exhaust pipe 12 Particulate collector 12a Filter chamber 12b Soot storage chamber 13 Honeycomb filter 14 Particulate 16 Air injection port 24 Bypass pipe 24a Upstream bypass pipe 26 Soot incinerator 27 Soot Guide tube 29 Air cylinder (valve driving means) 32 Rotary actuator (valve driving means) 41 Slide valve (first and third on-off valves) 42 Second on-off valve

Claims (1)

(57) [Claims] 1. A filter chamber (12a) provided in a middle of an exhaust pipe (11) connected to an exhaust manifold of an engine and accommodating a honeycomb filter (13), and the filter on the exhaust gas upstream side of the filter (13). Particulate collector (12) having a soot storage chamber (12b) provided below the chamber (12a)
And a downstream exhaust pipe (11
b) or an air injection port (16) provided in the collector (12) for injecting compressed air into the filter chamber (12a) when the filter (13) is backwashed, and one end of the exhaust gas from the filter (13). A bypass connected to the upstream exhaust pipe (11a) on the upstream side and the other end connected to the downstream exhaust pipe (11b) on the exhaust gas downstream side from the air injection port (16) and bypassing the collector (12) A pipe (24); a soot incinerator (26) provided in the middle of the bypass pipe (24).
A soot guide pipe (27) having one end connected to the soot storage chamber (12b) and the other end connected to an upstream bypass pipe (24a) on the exhaust gas upstream side from the soot incinerator (26); A first on-off valve provided in the upstream exhaust pipe (11a) between the connection part at one end of the pipe (24) and the collector (12);
(41), a second on-off valve (42) provided in the downstream exhaust pipe (11b) between the air injection port (16) and a connection portion at the other end of the bypass pipe (24), A third on-off valve (41) provided in the upstream bypass pipe (24a) on the exhaust gas upstream side from the connection at the other end of the soot guide pipe (27).
When the particulate (14) is collected by the filter (13), the first on-off valve (41) and the second on-off valve (42) are opened to close the third on-off valve (41), and the filter (13) Backwashing provided with valve driving means (29, 32) for closing the first on-off valve (41) and the second on-off valve (42) and opening the third on-off valve (41) at the time of backwashing Type particulate collection equipment.