JP2003193828A - Exhaust emission control device for diesel engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent adhering of particulate to a selector valve, and to supply proper quantity of oxygen to a filter, even if an opening/closing valve and a flow regulating valve are not provided, regarding an exhaust emission control device for a diesel engine for removing particulate in exhaust gas. <P>SOLUTION: This device is provided with the filter interposed in each of a plurality of pipes and scavenging particulate, the opening/closing valve interposed into each downstream side of the filters of the plurality of pipes, a heating means mounted on each upstream side of the filters of the plurality of pipes or each filter and reproducing each filter by heating, and a control device for controlling the switching of an ON/OFF state of the heating means and switching of an opening/closing state of the opening/closing valve, making the opening/closing valve on the filter side in a scavenging state as an open state by synchronizing with the OFF state of the heating means, and making the opening/closing means on the filter side in a reproduction state as a close state by synchronizing with the ON state of the heating means. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust emission control device for a diesel engine, which removes particulates in exhaust gas.

[0002]

2. Description of the Related Art In general, an exhaust system of a vehicle equipped with a diesel engine captures particulates contained in exhaust gas to purify the exhaust gas, and a particulate filter device filled with the captured particulates ( Hereinafter, an exhaust emission control device is installed in order to regenerate the "filter device". Here, "particulate" is a substance in which various substances produced during combustion in a halfway combustion in a diesel engine adhere to carbon components,
The size is dispersed from several μm to several tens μm.

As one of such exhaust emission control devices, a pair of filter devices are arranged in parallel, a switching valve is provided on the upstream side of each filter device, and when each filter device is clogged with particulates, the switching valve is activated. By switching,
It is known to alternately switch each filter device. Regarding such an exhaust emission control device, JP-A-11-125
The description will be given with reference to FIG. 9 by taking Japanese Patent Publication No. 109 as an example.

In the figure, an exhaust system 102 is connected to a diesel engine 101. The exhaust system 102 includes an upstream exhaust pipe 103 whose one end is connected to the diesel engine 101, a pair of first pipe 104 and second pipe 105 whose one end is connected to the other end of the upstream exhaust pipe 103, and a first pipe , 2
It has a downstream side exhaust pipe 106 connected to each of the other ends of the pipes 104 and 105.

The upstream side exhaust pipe 103 and the first and second pipes 10
A switching valve 107 is provided at a connecting portion 103 </ b> A with 4, 105. A first filter device 108 having an electric heater and a second filter device 109 having an electric heater are attached in the middle of the first and second pipes 104 and 105, respectively.

A bypass passage 110 is provided between the first pipe 104 and the second pipe 105, and an opening / closing valve 111 and a flow rate adjusting valve 112 are provided in the bypass passage 110. Then, the particulate matter is collected by one of the first filter device 108 and the second filter device 109. At the same time, the other filter device is regenerated by burning the particulate matter already collected by heating the electric heater while oxygen in the exhaust gas is supplied through the bypass passage 110.

[0007] Here, in the other filter device, at the time of regeneration, the opening / closing valve 111 is opened and the amount of exhaust gas passing through the bypass passage 110 is adjusted by using the flow rate adjusting valve 112, so that an appropriate amount of oxygen is obtained. Is given. In one of the filter devices, when the amount of collected particulates exceeds a predetermined amount, the switching valve 107 is operated to switch the flow of exhaust gas. When the switching valve 107 is switched,
The particulate matter collected in one of the filter devices is heated and incinerated to regenerate the one filter device, and the particulate matter contained in the exhaust gas is collected in the other filter device.

[0008]

However, the conventional exhaust emission control device has the following problems. Switching valve 10
Since 7 is arranged on the upstream side of the first filter device 108 and the second filter device 109 of the exhaust system 102, particulates in the exhaust gas easily adhere to the switching valve 107. Therefore, the durability of the switching valve 107 was poor, and the maintenance and inspection was troublesome.

Further, in order to regenerate the first filter device 108 and the second filter device 109, a bypass passage 110 for supplying oxygen in the exhaust gas, an on-off valve 111 for adjusting the exhaust gas to an appropriate amount, and a flow rate adjusting valve 112. And are required.
Moreover, particulates in the exhaust gas are likely to adhere to the on-off valve 111 and the flow rate adjusting valve 112. When particulates adhere to the on-off valve 111 and the flow rate adjusting valve 112, the flow rate of the exhaust gas passing through the bypass passage 110 changes, and an appropriate amount of oxygen is supplied to the first filter device 108 and the second filter device 109 in the regenerated state. There was a problem that it was difficult.

The present invention has been made to solve the above-mentioned problems, and an object thereof is to prevent particulates from adhering to a switching valve and to provide an appropriate amount without an opening / closing valve or a flow rate adjusting valve. An object of the present invention is to provide an exhaust emission control device for a diesel engine that can supply oxygen to the filter.

[0011]

The invention according to claim 1 is
An exhaust pipe provided in the middle of the exhaust system, a plurality of pipes branching from the exhaust pipe and arranged in parallel, a filter that is interposed in each of the plurality of pipes, and collects particulates; On-off valves respectively installed on the downstream side of the filter of the pipe, and on the upstream side of the filters of the plurality of pipes or on the respective filters, heating means for heating and regenerating the respective filters, and the heating The switching of the ON / OFF state of the means and the switching of the open / close state of the on-off valve are controlled to open the on-off valve on the filter side in the collecting state in synchronization with the OFF state of the heating means, and the heating means. And a control device for closing the on-off valve on the filter side in the regenerating state in synchronization with the ON state of.

According to a second aspect of the present invention, an exhaust pipe provided in the middle of the exhaust system, a plurality of pipes branching from the exhaust pipe and arranged in parallel, and interposed in the plurality of pipes, respectively. A filter that collects particulates, an on-off valve that is respectively provided on the downstream side of the filters of the plurality of pipes, an oxygen supply unit that supplies oxygen to each of the plurality of filters, and a plurality of pipes A heating unit which is mounted on the upstream side of the filter or on each of the filters and which heats and regenerates each of the filters, controls ON / OFF state switching of the heating unit and switching of the open / close state of the on-off valve, The filter-side on-off valve in the collection state is opened in synchronization with the OFF state of the heating means and the filter-side on-off valve in the regeneration state is closed in synchronization with the ON state of the heating means. Characterized in that it comprises a control device for the.

According to a third aspect of the present invention, an exhaust pipe provided in the middle of the exhaust system, a plurality of pipes branching from the exhaust pipe and arranged in parallel, and interposed in the plurality of pipes, respectively. A filter for collecting particulates, a container provided on the upstream side of the filter of the exhaust system, an opening / closing valve respectively provided on the downstream side of the filters of the plurality of pipes, and a filter of the plurality of pipes. An upstream side or each of the filters is mounted respectively, and heating means for heating and regenerating each of the filters, controlling ON / OFF state of the heating means and switching of the open / close state of the open / close valve are controlled,
In synchronization with the OFF state of the heating means, the on-off valve on the filter side in the collecting state is opened and the O of the heating means is turned off.
It is characterized in that it is provided with a control device that makes the on-off valve on the filter side in the regenerating state in a semi-closed state in synchronization with the N state.

According to a fourth aspect of the present invention, an exhaust pipe provided in the middle of the exhaust system, a plurality of pipes branched from the exhaust pipe and arranged in parallel, and interposed in the plurality of pipes, respectively. A filter for collecting particulates, a container provided on the upstream side of the filter of the exhaust system, an air replenishing means that is attached to the filter and takes in air from the outside air, and a downstream side of the filters of the plurality of pipes. Open / close valves respectively installed on the upstream side of the filters of the plurality of pipes or each of the filters, and heating means for heating and regenerating each of the filters, and an ON / OFF state of the heating means. The switching and the switching of the open / closed state of the open / close valve are controlled so that the open / close valve on the filter side in the collecting state is opened in synchronization with the OFF state of the heating means. Characterized in that in synchronization with N states and a control device for the filter side of the opening and closing valve in reproduction state in a semi-closed state.

According to a fifth aspect of the present invention, in the exhaust gas purification device for a diesel engine according to the third or fourth aspect, the container is a muffler. According to a sixth aspect of the present invention, in the exhaust emission control system of the diesel engine according to the third or fourth aspect, the container is arranged over the plurality of pipes.

(Operation) In the invention according to claim 1,
The control device controls the switching of the ON / OFF state of the heating means and the switching of the open / close state of the open / close valve, and the open / close valve on the filter side in the collecting state is opened in synchronization with the OFF state of the heating means. At the same time, the on-off valve on the filter side in the regenerating state is closed in synchronization with the ON state of the heating means.

Hereinafter, the on-off valve on the filter side in the collecting state will be referred to as "on-off valve on the collecting side", and the on-off valve on the filter side in the regenerating state will be referred to as "regeneration side on-off valve". The exhaust gas is
When passing through the filter in the collecting state, the filter collects and removes particulates. The exhaust gas from which the particulates have been removed flows through the open / close valve on the collection side, so that the particulates are prevented from adhering to the open / close valve.

On the other hand, the pulsating exhaust gas enters the filter in the regenerated state and is reflected by the filter. Therefore, the exhaust gas continuously enters and leaves the filter, and oxygen in the exhaust gas is continuously supplied to the filter. At the filter, the particulates already collected are incinerated and the filter is regenerated. In the invention according to claim 2, the control device controls the switching of the ON / OFF state of the heating means and the switching of the open / close state of the on-off valve,
The open / close valve on the collection side is opened in synchronization with the OFF state of the heating means, and the open / close valve on the regeneration side is closed in synchronization with the ON state of the heating means.

Then, the same operation as that of the invention according to claim 1 occurs. Further, an appropriate amount of oxygen is supplied to the filter in the regenerated state by the pulsating exhaust gas inflow / outflow and oxygen supply means. With this appropriate amount of oxygen, the particulates already collected are incinerated and the filter is regenerated. According to the third aspect of the invention, the control device controls the ON / OFF state switching of the heating means and the opening / closing state switching of the opening / closing valve, and the opening / closing of the collecting side is synchronized with the OFF state of the heating means. The valve is opened and the on-off valve on the regeneration side is semi-closed in synchronization with the ON state of the heating means.

First, the pressure fluctuation of the pulsation of the exhaust gas is reduced by the wave absorbing action of the container. (A) When the pressure fluctuation of the pulsation of the exhaust gas is reduced to the extent that it is not smoothed by the wave absorption action of the container, and (b) When the pressure fluctuation of the pulsation of the exhaust gas is smoothed by the wave absorption action of the container. And the action is different. (A) will be described.

The exhaust gas that has passed through the container passes through a filter in a trapped state, is trapped by the filter, and particulates are removed. The exhaust gas from which the particulates have been removed flows through the open / close valve on the collection side, so that the particulates are prevented from adhering to the open / close valve. On the other hand, the pulsating exhaust gas enters the regenerating filter and is reflected by the filter. Therefore, the exhaust gas continuously enters and leaves the filter, and oxygen in the exhaust gas is continuously supplied to the filter. At the filter, the particulates already collected are incinerated and the filter is regenerated.

Part of the exhaust gas is discharged to the outside through the on-off valve on the regeneration side in the semi-closed state. Therefore, oxygen is supplied by the reflection of exhaust pulsation and a part of the exhaust gas passing through the on-off valve on the regeneration side in the semi-closed state.
(B) will be described. The pulsating exhaust gas becomes a smooth flow with a constant pressure due to the wave absorbing action of the container (the density of the exhaust gas pressure is eliminated).

The exhaust gas smoothed in the container passes through a filter in a trapped state and is trapped by the filter to remove particulates. The exhaust gas from which the particulates have been removed flows through the open / close valve on the collection side, so that the particulates are prevented from adhering to the open / close valve.

On the other hand, since the pulsation of the exhaust gas is smoothed by the wave absorbing action of the container, the exhaust gas is not reflected by the filter in the regenerated state. Since the on-off valve on the regeneration side is in a semi-closed state, an appropriate amount of oxygen in exhaust gas is supplied to the filter without the conventional bypass passage, on-off valve, and flow rate adjustment valve.
A small amount of exhaust gas passes through the filter. At the filter, the particulates already collected are incinerated and the filter is regenerated.

Since an appropriate amount of exhaust gas is supplied to the filter in the regenerated state, cooling of the filter in the regenerated state is prevented. In the invention according to claim 4, the control device controls the switching of the ON / OFF state of the heating means and the switching of the open / close state of the open / close valve, and the open / close valve on the collection side is synchronized with the OFF state of the heating means. Is opened and the on-off valve on the regeneration side is semi-closed in synchronization with the ON state of the heating means.

Then, the same action as that of the third aspect of the invention occurs, but it is taken into the filter by the air supply means separately from the exhaust gas. The air supply means plays a role of supplying oxygen and adjusting the amount of oxygen. In the invention described in claim 5, the pressure pulsation of the exhaust gas is absorbed by the muffler. In the invention according to claim 6, since the exhaust gas hits the container and splits, the pulsation of the exhaust gas is easily reduced.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. << Embodiment 1 >> An embodiment (Embodiment 1) of an exhaust emission control apparatus for a diesel engine according to claims 3 and 5 will be described with reference to FIGS.

In the figure, a diesel engine 1 is mounted on a vehicle (not shown), and an exhaust manifold 2 is mounted on the diesel engine 1. An exhaust system 3 is connected to the exhaust manifold 2. The exhaust system 3 includes an upstream exhaust pipe 4 having one end connected to the exhaust manifold 2, and a plurality of (two in the present embodiment) first pipes 5 having one end connected to the other end of the upstream exhaust pipe 4. , The second pipe 6, and the downstream exhaust pipe 7 connected to the other ends of the first and second pipes 5, 6. The first pipe 5 and the second pipe 6 are parallel to the center of the vehicle.

The diesel engine 1 has an intake pipe 8, and a turbocharger 9 is installed in the middle of the intake pipe 8. The turbocharger 9 includes a compressor unit 9A and
It is composed of a turbine section 9B provided in the upstream exhaust pipe 4. An exhaust brake valve 10, which is a butterfly valve, and a container 11 located downstream of the exhaust brake valve 10 are interposed in the upstream exhaust pipe 4. A muffler expansion chamber is used as the container 11, for example.

The volume of the container 11 is comprehensively determined in consideration of the layout and the like. For example, a volume of 50% or more and 100% or less of the total displacement of the diesel engine 1 is adopted. The first filter device 12 is provided in the middle of the first pipe 5, and the second filter device 13 is provided in the middle of the second pipe 6.

The first filter device 12 includes a housing 12
A and the filter 12B mounted in the housing 12A
And a heating means which is mounted in the housing 12A and includes an electric heater portion 12C arranged on the upstream side of the filter 12B. The filter 12B has a substantially cylindrical shape made of a porous member such as ceramic,
A large number of cells substantially parallel to the exhaust gas flow are formed in 2B by the honeycomb-shaped partition walls 12D, and the inlet and outlet of each cell are alternately plugged by a blocking material. Then, when the exhaust gas flows into the adjacent cells via the partition 12D, the particulates contained in the exhaust gas are collected by the partition 12D.

Like the first filter device 12, the second filter device 13 has a housing 13A and a housing 13A.
Filter 13B mounted in A and housing 13A
The heating means is comprised of an electric heater portion 13C mounted inside and disposed upstream of the filter 13B. The filter 13B has a partition wall 13D having the same structure as the partition wall 12D of the filter 12B.

As a heating means, the electric heater section 12 is used.
A burner may be used in place of C and 13C (see, for example, Japanese Patent Laid-Open No.
001-50031). A first opening / closing valve 14 is provided downstream of the first filter device 12 in the first pipe 5. The first opening / closing valve 14 is a butterfly valve, and controls ON / OFF of the flow of exhaust gas. The first on-off valve 14 is connected to a first actuator 15 that is an air cylinder that drives the first on-off valve 14. First actuator 1
5 is connected to the first solenoid valve 15A. A second opening / closing valve 16 is provided downstream of the second filter device 13 in the second pipe 6. The 2nd on-off valve 16 consists of a butterfly valve, and controls the flow of exhaust gas ON / OFF. As the butterfly valve, the exhaust brake valve 10 or the like can be used,
The structure is simple and the cost can be reduced.

The second on-off valve 16 is connected to a second actuator 17 which is an air cylinder for driving the second on-off valve 16. The second solenoid valve 17A is connected to the second actuator 17. The diesel engine 1 is equipped with a rotation speed sensor 18 for detecting the engine speed, and the intake pipe 8 is equipped with a boost pressure sensor 19 for detecting boost pressure.

A pressure sensor 20 for detecting the pressure of exhaust gas in the upstream exhaust pipe 4 is mounted near the other end of the upstream exhaust pipe 4 of the first pipe 5. A first temperature sensor 21 for detecting the temperature of the filter 12B is mounted inside the first filter device 12, and inside the second filter device 13,
A second temperature sensor 22 that detects the temperature of the filter 13B is attached.

A control device 23 is provided for switching between the collecting state and the regenerating state of the first filter device 12 and the second filter device 13. The control device 23 controls ON / OFF switching of the heating means, and at the same time controls switching of the open / closed states of the first and second opening / closing valves 14 and 16. That is, the control device 23 controls the OFs of the electric heaters 12C and 13C.
The first and second filters 12 in the collecting state in synchronization with the F state
The first and second on-off valves 14 and 16 on the B and 13B sides are controlled to be in the open state, and the first and second filters 12B and 1 in the regenerating state are synchronized with the ON states of the electric heaters 12C and 13C.
The first and second on-off valves 14 and 16 on the 3B side are controlled to be in the closed state.

On the input side of the control device 23, a rotation speed sensor 18, a boost pressure sensor 19 and a pressure sensor 20 are provided.
The first temperature sensor 21 and the second temperature sensor 22 are connected to each other. The first solenoid valve 15A, the second solenoid valve 17A, the electric heater portion 12C, and the electric heater portion 13C are connected to the output side of the control device 23.

The control device 23, when one of the first on-off valve 14 and the second on-off valve 16 is fully opened,
It has a program for outputting to the first solenoid valve 15A and the second solenoid valve 17A so as to control the other half to a semi-closed state (almost full closed state). Next, the operation of the exhaust emission control device of the diesel engine will be described. Boost pressure sensor 1
9. The signal of the pressure of the exhaust gas from the pressure sensor 20 is input to the control device 23. The control device 23 executes the flowchart shown in FIG. As a result, the particulate matter is collected by one of the first filter apparatus 12 and the second filter apparatus 13, and when the collected particulate matter exceeds a predetermined amount, the flow of the exhaust gas is switched. Then, the particulate matter collected in one of the filter devices is heated and incinerated to regenerate the one filter device, and the particulate matter contained in the exhaust gas is collected in the other filter device. In this way, the first filter device 12 and the second filter device 13
Collects and reproduces alternately.

This will be described in detail. Regarding the operation timings of the first filter device 12 and the second filter device 13, the phases of collection and regeneration are 180 degrees out of phase, but since they are the same operation, the first filter device 12 side will be described as an example. To do. In FIG. 1, the first filter device 12 is in the collecting state,
The case where the filter device 13 is on the reproducing side is shown in the drawing, and will be described below with reference to this.

On the side of the first filter device 12, FIG.
The program shown in the flowchart in FIG.
Executed by. In the initial state of step S1 of FIG. 2, the first filter device 12 side is in the collecting state, the electric heater 12C is in the OFF state, and the first opening / closing valve 14 is in the fully open state.

The second filter device 13 side is the regeneration side, the electric heater 13C is in the ON state, and the second on-off valve 16 is in the semi-closed state (almost fully closed state). In this state, the exhaust gas from the diesel engine 1 flows into the container 11 from the exhaust manifold 2 through the upstream exhaust pipe 4 by the operation of the diesel engine 1 on the first filter device 12 side. In the container 11, the exhaust gas is converted from a pulsating flow whose sparseness and density changes periodically into a smooth flow by the wave absorbing action of the container 11, and flows out from the container 11 to the upstream exhaust pipe 4 again. The exhaust gas, which is a smooth flow, flows into the first pipe 5, and the first filter device 12 collects the particulates contained in the exhaust gas.

As the particulate matter contained in the exhaust gas is collected by the first filter device 12, the first filter device 12 eventually becomes clogged (that is, the particulate matter deposited on the first filter device 12 is When a predetermined amount is reached), the pressure difference between the exhaust gas upstream and downstream of the first filter device 12 reaches a predetermined value.

Here, whether or not the pressure difference of the exhaust gas has reached a predetermined value is determined by the procedure of steps S2 to S7. In step S2, the pressure Pf of the exhaust gas that is a smooth flow is detected by the pressure sensor 20. This pressure Pf is read by the arithmetic unit of the control device 23 and temporarily stored.

In step S3, the rotation speed sensor 18
The engine speed N detected by is read by the arithmetic unit of the control device 23 and temporarily stored. Step S4
At, the boost pressure P1 detected by the boost pressure sensor 19 is read into the arithmetic unit of the control device 23 and temporarily stored. In step S5, the arithmetic unit of the control device 23 causes the pressure loss ΔP = first filter device 1
2 the upstream exhaust gas pressure-the downstream exhaust gas pressure difference of the first filter device 12 = inlet side pressure Pf-outlet side P
a (atmospheric pressure) is calculated and temporarily stored.

In step S6, the pressure loss coefficient α is calculated from the pressure loss ΔP, the engine speed N, and the boost pressure P1. In step S7, it is calculated whether or not the pressure loss coefficient α exceeds a threshold value. The pressure loss coefficient α
If is determined to exceed the threshold value, the process proceeds to step S8.

In step S8, the electric heater 12C is switched from the OFF state to the ON state and the electric heater 13C is changed from the ON state to the O state according to a command from the control device 23.
It is switched to the FF state. At the same time, the first electromagnetic valve 15A and the second electromagnetic valve 17A are driven by a command from the control device 23. First solenoid valve 15A → first actuator 15
→ The operation is performed in the order of the first opening / closing valve 14, and the first opening / closing valve 14 is switched from the fully open state to the semi-closed state (almost fully closed state). At the same time, the operation of the second solenoid valve 17A → the second actuator 17 → the second opening / closing valve 16 is performed, and the second opening / closing valve 16 is switched from the semi-closed state (almost fully closed state) to the fully opened state.

At this point, the first filter device 12 is switched from the collection state to the regeneration state. On the other hand, the second filter device 13 is switched from the regeneration state to the collection state. In the state after this switching, the particulate matter is collected by the second filter device 13 and the particulate matter collected by the first filter device 12 is heated and incinerated so that the first filter device 12 operates as follows. Is played.

In step S9, the electric heater unit 12C of the first filter device 12 is energized, and the electric heater unit 1 is turned on.
When the temperature of 2C reaches or exceeds the temperature at which particulates can burn, the particulates collected by the filter 12B are ignited. In step S10, the particulates are heated and incinerated by the electric heater unit 12C,
It is determined whether the temperature of the first filter device 12 exceeds a predetermined value.

In step S11, when the temperature of the first filter device 12 exceeds the predetermined value, the electric heater unit 12
Due to the continuous heating action of C, the particulates collected in the filter 12B are incinerated and the filter 12B is regenerated. As a result, the pressure loss ΔP decreases. In step S12, the electric heater unit 12C is controlled to be in the OFF state when the energization time has passed a certain time, and returns to the initial state in step S1.

In this way, the collection state and the regeneration state of the first filter device 12 are alternately repeated. Also, the second
In the filter device 13, the collection state and the regeneration state are alternately repeated in a phase opposite to that of the first filter device 12. Next, the operation of this embodiment will be described. Exhaust gas is guided from the diesel engine 1 to the container 11 via the upstream exhaust pipe 4. As described above, the exhaust gas is a pulsating flow whose density varies periodically, and is converted into a smooth flow having a constant pressure by the wave absorption action of the container 11 and passes through the container 11 (the pressure density of the exhaust gas is eliminated. ).

The smoothed exhaust gas passes through the first filter device 12, is collected by the first filter device 12, and the particulates are removed. At the same time, the exhaust gas is guided to the second filter device 13 in the regenerated state. The second on-off valve 16 on the second filter device 13 side is controlled to be in a semi-closed state (almost fully closed state). Since the exhaust gas guided to the second filter device 13 is smoothed, it flows into the second filter device 13 one after another without being reflected.

The exhaust gas, which is a smooth flow, flows in a small amount by the second on-off valve 16 in a semi-closed state (almost fully closed state) and is used as an oxygen source for regeneration. That is, since a small amount of exhaust gas passes through the second filter device 13, oxygen in the exhaust gas is continuously supplied to the second filter device 13. The exhaust gas smoothed by the wave absorbing action of the container 11 is not reflected by the second filter device 13 in the regenerated state.

Since the second on-off valve 16 on the regeneration side is in a semi-closed state (almost fully closed state), the bypass passage, the on-off valve, and
Even if there is no flow rate adjusting valve, an appropriate amount of oxygen in the exhaust gas is supplied to the second filter device 13, and a small amount of exhaust gas passes through the second filter device 13 and is discharged to the outside. In the second filter device 13, the particulates already trapped by the oxygen in the exhaust gas are incinerated, and the second filter device 13 is regenerated. Exhaust gas generated by incineration of particulates is second
It flows out to the downstream side exhaust pipe 7 via the opening / closing valve 16.

The exhaust gas from which the particulates have been removed flows through the second opening / closing valve 16 on the side of the second filter device 13, so that the particulates are prevented from adhering to the second opening / closing valve 16. Then, since an appropriate amount of exhaust gas is supplied to the second filter device 13 in the regenerated state, the electric heater unit 13C and the filter 13B of the second filter device 13 in the regenerated state are not cooled.

According to the above configuration, the following effects can be obtained. First, since the first opening / closing valve 14 is provided downstream of the first filter device 12 and the second opening / closing valve 16 is provided downstream of the second filter device 13, the particulates are the first opening / closing valve. It is possible to prevent the first and second on-off valves 14 and 16 from adhering to the first and second on-off valves 16 and to facilitate maintenance and inspection.

Second, the second filter device 13 in the regenerated state.
When regenerating, the second on-off valve 16 is in a semi-closed state (almost fully closed state), so that an appropriate amount of exhaust gas can be supplied to the filter device, and the bypass passage, the on-off valve, and the flow rate adjustment valve as in the conventional case are Even if it does not exist, an appropriate amount of oxygen in the exhaust gas can be supplied to the second filter device 13 in the regenerated state. Third,
Since the exhaust gas supplied to the second filter device 13 in the regenerated state is an appropriate amount, it is possible to prevent the excessive exhaust gas from being supplied to the second filter device 13 in the regenerated state, and the electric heater section 12 thereof is provided.
Cooling of C, 13C and filters 12B, 13B can be prevented. Therefore, the electric heaters 12C and 13 associated with cooling
The power supplied to C is reduced and the filter 12 by cooling is used.
It is possible to prevent the defective reproduction due to the temperature decrease of B and 13B.

Fourthly, the open / close valves 14 and 16 can be replaced by precision valves such as conventional flow rate adjusting valves, and ON / OFF valves having a simple structure such as butterfly valves can be used. It is possible to reliably prevent the adhesion of curate. << Embodiment 2 >> FIG. 3 shows an embodiment (Embodiment 2) of an exhaust emission control device for a diesel engine according to the third and sixth aspects of the present invention.

The exhaust purification system for a diesel engine according to the second embodiment has the same structure as the exhaust purification system for a diesel engine according to the first embodiment, and the same reference numerals are given to the same components for the description. It is omitted, and only different parts will be described. In addition, the control device 23
The same control as that in the flowchart (FIG. 2) of the first embodiment is performed.

In this embodiment, the container 11 shown in FIG.
Instead of this, the container 31 is used. The container 31 is connected to the end portion 4A of the upstream exhaust pipe 4. The container 31 is
It has an elongated shape along the left-right direction of the vehicle, and its volume is smaller than that of the container 11 made of a muffler.
The container 31 is connected to the upstream exhaust pipe 4 from the end 5A of the first pipe 5.
To the end 6 of the second pipe 6 via the end 4A.

According to this structure, the pulsation of the exhaust gas hits the container 31 and splits, so that the pulsation of the exhaust gas can be easily reduced. Further, since the container 31 is arranged along the left-right direction of the vehicle, it can have a layout corresponding to it, and can generally have a smaller volume than a muffler having a large volume. The degree of freedom of can be increased.

<< Third Embodiment >> FIG. 4 shows an embodiment (third embodiment) of an exhaust emission control system for a diesel engine according to the third and fifth aspects of the present invention. The exhaust emission control device for a diesel engine according to the third embodiment has basically the same configuration as the exhaust emission control device for a diesel engine according to the first embodiment, and the same components are designated by the same reference numerals for the description. It is omitted, and only different parts will be described. It should be noted that FIG. 4 is a diagram illustrating FIG.
The same configuration as the above is simplified for explanation. Further, control device 23 performs the same control as the flowchart (FIG. 2) of the first embodiment.

In the figure, the container 41 has a volume that reduces the pulsation of exhaust gas to the extent that it does not smooth, and is smaller than the container 11 of the first embodiment. This causes the following effects. The operation of the third embodiment is different from that of the first embodiment, and only different points will be described.

When the first filter device 12 is in the collecting state,
The case where the filter device 13 is in the reproduction state will be described as an example. In this case, the first on-off valve 14 on the collection side is in a fully open state, and the second on-off valve 16 on the regeneration side is in a semi-closed state (almost fully closed state). First, the pressure fluctuation of the pulsation of the exhaust gas is reduced to the extent that it is not smoothed by the wave absorbing action of the container 41. The exhaust gas that has passed through the container 41 passes through the first filter device 12 in the trapped state, is collected by the first filter device 12, and the particulates are removed.
The exhaust gas from which the particulates have been removed flows through the on-off valve 14 on the collection side.
Adhesion to 16 is prevented.

Although the pulsation of the exhaust gas is reduced by the wave absorbing action of the container 41, it is not a smooth flow. Therefore,
The pulsating exhaust gas enters the second filter device 13 in the regenerated state and is reflected by the second filter device 13. Therefore, the exhaust gas continuously enters and leaves the second filter device 13 in the regenerated state, and the oxygen in the exhaust gas is continuously supplied to the second filter device 13.

Here, since the container 41 has a volume that reduces exhaust pulsation to the extent that it does not smooth it, the amount reflected by the second filter device 13 is small, and an appropriate amount of exhaust gas is supplied to the second filter device 13. To be done. The particulate matter already collected by the second filter device 13 is incinerated and the second filter device 13 is regenerated.

A part of the exhaust gas is discharged to the outside through the second opening / closing valve 16 on the regeneration side in the semi-closed state (almost fully closed state). Therefore, the supply of oxygen is performed by the reflection of exhaust pulsation and a part of the exhaust gas passing through the second opening / closing valve 16 in the semi-closed state (almost fully closed state) on the regeneration side. In this way, the exhaust pulsation is not smoothed by reducing the size of the container 41, and the exhaust gas pulsation is continuously utilized by utilizing the reflection of the exhaust pulsation in a state where the amplitude of the exhaust pulsation is reduced. It is supplied to the filter device 13.

According to the third embodiment, the following effects can be obtained. First, the same effect as that of the first embodiment is achieved. Second
In addition, since the container 41 has a volume that reduces exhaust pulsation to the extent that it does not smooth, it is possible to supply an appropriate amount of exhaust gas to the first and second filter devices 12 and 13. As a result, an appropriate amount of oxygen in the exhaust gas can be supplied to the regenerated second filter device 13 without the conventional bypass passage, on-off valve, and flow rate adjusting valve.

Thirdly, by appropriately selecting the volume of the container 41, the amount of reflection of exhaust pulsation in the second filter device 13 in the regenerated state is reduced, and the second filter device 1 in the regenerated state is reduced.
The flow rate of the exhaust gas supplied to the No. 3 can be adjusted.
As a result, similar to the third effect of the first embodiment, the cooling of the second filter device 13 can be prevented, and the regeneration failure of the second filter device 13 in the regenerated state can be prevented.

<< Embodiment 4 >> FIG. 5 shows an embodiment (Embodiment 4) of an exhaust emission control system for a diesel engine according to the present invention. The diesel engine exhaust emission control device according to the fourth embodiment has the same configuration as the diesel engine exhaust emission control device according to the first embodiment, and the same components are designated by the same reference numerals and description thereof is omitted. Only different parts will be described. Note that FIG. 5 shows the same configuration as that of FIG. In addition, the control device 2
3 performs the same control as the flowchart (FIG. 2) of the first embodiment.

When the first filter device 12 is in the collecting state,
The case where the filter device 13 is in the reproduction state will be described as an example. In this case, the first on-off valve 14 on the collection side is in a fully open state, and the second on-off valve 16 on the regeneration side is in a semi-closed state (almost fully closed state).

A first air supply means 51 is attached to the first filter device 12. The first air supply means 51 is composed of an air intake part 51A for taking in air (oxygen) and an air introduction pipe 51B. The air introducing pipe 51B is connected to the front wall 12E of the first filter device 12 so that the intake air is guided into the first filter device 12.

A second air supply means 52 is attached to the second filter device 13. The first air supply means 52 is composed of an air intake portion 52A that takes in air, and an air introduction pipe 52B. The air introduction pipe 52B is connected to the front wall 13E of the second filter device 13 so that the intake air is guided to the inside of the second filter device 13. The first and second air supply means 51, 52 take in air (oxygen) into the first filter device 12 and the second filter device 13 separately from the exhaust gas.

In the fourth embodiment, the same operation as in the first embodiment occurs. In addition to the exhaust gas, air (oxygen) is supplied to the second filter device 1 by the second air supply means 52.
Taken in 3. The first air supply means 51 on the collection side is
The control device 23 controls so as not to take in air.

The second air supply means 52 plays a role of supplying oxygen and adjusting the amount of oxygen. According to the present embodiment, the following effects are obtained in addition to the effects of the first embodiment. The second air supply means 52 can supply an appropriate amount of air (oxygen) to the second filter device 13 in the regenerated state. That is, the second air replenishing means 52 plays the role of adjusting the amount of oxygen, and has the effect of being able to finely adjust the amount of oxygen supplied to the second filter device 13 in the regenerated state.
The first air supply means 51 has the same effect as the second air supply means 52.

<Embodiment 5> FIG. 6 shows an embodiment (Embodiment 5) of an exhaust emission control apparatus for a diesel engine according to the first aspect of the present invention. The exhaust emission control device for a diesel engine according to the fifth embodiment has basically the same configuration as the exhaust emission control device for a diesel engine according to the first embodiment, and the same components are designated by the same reference numerals for the description. It is omitted, and only different parts will be described.
Note that FIG. 6 is the same configuration as that of FIG. 1 for explaining the first embodiment but simplified for explanation. In addition, the control device 23
Performs the same control as the flowchart (FIG. 2) of the first embodiment.

In the figure, the fifth embodiment is different in that the container 11 of the first embodiment is not used. The case where the first filter device 12 is in the collection state and the second filter device 13 is in the regeneration state will be described as an example. In this case, the first opening / closing valve 14 on the collection side is in the fully opened state, and the second opening / closing valve 14 on the regeneration side is
The on-off valve 16 is in a fully closed state. The first filter device 12 and the second filter device 13 alternately repeat collection and regeneration.

The operation of this embodiment will be described. The exhaust gas is collected by the first filter device 12 when passing through the first filter device 12 in the collected state, and particulates are removed. The exhaust gas from which the particulates have been removed flows through the first on-off valve 14 on the collection side, so that the particulates are prevented from adhering to the first on-off valve 14.

On the other hand, the pulsating exhaust gas is the second exhaust gas in the regenerated state.
It enters the filter device 13 and is reflected by the second filter device 13. When the second filter device 13 is regenerated, the reflection of exhaust pulsation is used as the supply of exhaust gas (oxygen). Therefore, the exhaust gas continuously enters and leaves the second filter device 13, and the oxygen in the exhaust gas is continuously supplied to the second filter device 13. In the second filter device 13, the particulates already collected are incinerated, and the second filter device 13 is regenerated.

When the second filter device 13 is regenerated,
The exhaust gas generated by the incineration of the particulates rides on the exhaust pulsation that goes around to the first filter device 12 side, goes around to the first filter device 12 side, and is discharged. In this case, by increasing the volumes of the first filter device 12 and the second filter device 13, the exhaust gas can be made to have an appropriate amount without changing the supply amount, and the first filter device 1
2, It is also possible to prevent cooling of the second filter device 13. The first filter device 12 and the second filter device 13 having such a large volume can be applied to a special vehicle having a sufficient vehicle space.

According to the fifth embodiment, the same effect as that of the first embodiment can be obtained. << Sixth Embodiment >> FIG. 7 shows an embodiment (sixth embodiment) of an exhaust emission control device for a diesel engine according to the second aspect of the present invention. The exhaust purification system for a diesel engine according to the sixth embodiment has basically the same configuration as the exhaust purification system for a diesel engine according to the first embodiment.
The same components are given the same reference numerals and the description thereof is omitted, and only different portions will be described. Note that FIG.
2 is the same configuration as that of FIG. 1 for explaining the first embodiment but simplified for explanation. Further, control device 23 performs the same control as the flowchart (FIG. 2) of the first embodiment.

The sixth embodiment is a container 11 of the first embodiment.
Is different from the point that oxygen supply means is provided. In the figure, the first filter device 12 is provided with a first oxygen supply means 71, and the second filter device 13 is provided with a second oxygen supply means 72. First
The oxygen supply means 71 supplies oxygen to the first filter device 12 separately from oxygen in the exhaust gas.

The second oxygen supply means 72 supplies oxygen to the second filter device 13 separately from oxygen in the exhaust gas. The case where the first filter device 12 is in the collection state and the second filter device 13 is in the regeneration state will be described as an example. In this case, the first opening / closing valve 14 on the collection side is in the fully opened state, and the second opening / closing valve 14 on the regeneration side is
The on-off valve 16 is in a fully closed state. The first filter device 12 and the second filter device 13 alternately repeat collection and regeneration.

In synchronization with the fully closing operation of the second on-off valve 16 of the second filter device 13, oxygen is supplied to the second filter device 13 in the regenerated state separately from the oxygen in the exhaust gas by the second oxygen supply means 72. It In the present embodiment, in addition to the same operation as in the fifth embodiment, an appropriate amount of oxygen is supplied to the second filter device 13 in the regenerated state by the pulsating exhaust gas inflow and outflow and the second oxygen supply means 72.

With this appropriate amount of oxygen, the particulates already collected are incinerated and the second filter device 13 is regenerated. In this case, by increasing the volumes of the first filter device 12 and the second filter device 13, the exhaust gas can be adjusted to a relatively appropriate amount without changing the supply amount, and the first filter device 12 and the second filter device 13 can be cooled. It can also be prevented. The first filter device 12 and the second filter device 12 having such a large volume
The filter device 13 can be applied to a special vehicle having a sufficient vehicle space.

According to the sixth embodiment, in addition to the effects of the fifth embodiment, the first and second oxygen supply means 71, 72 supply the first filter device 12 and the second filter device 13 in the regenerated state. The effect of being able to finely adjust the amount of oxygen to be produced is exerted. Incidentally, the first to sixth embodiments described above
In the above, the case where the number of pipes and filter devices is two has been described, but the number of pipes and filter devices may be three or more.

For example, FIG. 8 shows an essential part of an exhaust emission control device for a diesel engine when the number of pipes and filter devices is three. In the figure, an exhaust system 81 has an upstream side exhaust pipe 82 connected to the diesel engine 1 (shown in FIG. 1). A container 83 is provided at the other end of the upstream exhaust pipe 4.
One side is connected to the other side of the container 83 and the three first pipes 8
4, one end of each of the second pipe 85 and the third pipe 86 is connected.

First pipe 84, second pipe 85, third pipe 8
The other end of 6 is connected to the downstream exhaust pipe 87. First
A first filter device 84A and a first opening / closing valve 84B are installed in the middle of the pipe 84. In the middle of the second pipe 85,
The second filter device 85A and the second opening / closing valve 85B are mounted.

A third filter device 86A and a third open / close valve 86B are mounted in the middle of the third pipe 86. By closing any one of the first opening / closing valve 84B, the second opening / closing valve 85B, and the third opening / closing valve 86B and opening the other, the first filter device 84A, the second filter device 85A, and the third filter device 86A One of the other is played and the other first
Particulates are collected by the filter device.

For example, the third on-off valve 86B is closed to regenerate the third filter device 86A, and the first on-off valve 84 is regenerated.
B, the second on-off valve 85B is in the open state and the first filter device 8
Particulates are collected by 4A and the second filter device 85A. With such a configuration, the volume and height of each first filter device 84A, 85A, 86A can be reduced, and the space on the passenger room side of a vehicle layout such as a bus can be increased.

Further, in the first to sixth embodiments described above, the on-off valves 14 and 16 are individually driven by actuators, but the on-off valves 14 and 16 can be replaced by appropriate ones. It is also possible to simplify the structure by synchronously driving with one actuator by the synchronization mechanism.

Furthermore, in the first to sixth embodiments, the heating means is the filters 12B and 13B.
However, it is not limited to such an arrangement. As the heating means, the heating means (electric heater or burner) may be arranged on the filters 12B and 13B themselves, or the heating means (electric heater or burner) may be arranged on the first and second pipes 5 and 6. it can.

[0092]

According to the first aspect of the invention, since the on-off valves are provided on the downstream side of the plurality of filters, the particulates are prevented from adhering to the on-off valves, and the durability of the on-off valves is improved. It can be secured and maintenance inspection can be simplified. According to the invention of claim 2, in addition to the effect of the invention of claim 1, since the filter is provided with the oxygen supply means, an appropriate amount can be obtained without the conventional bypass passage, on-off valve and flow rate adjusting valve. Oxygen can be supplied to the filter.

Further, the amount of oxygen supplied to the filter in the regenerated state can be finely adjusted by the oxygen supply means. According to the invention of claim 3, in addition to the effect of the invention of claim 1, the following effect is exhibited. Since the on-off valve on the regeneration side is in the semi-closed state, an appropriate amount of exhaust gas can be supplied to the filter in the regenerated state. Therefore, it is possible to prevent excessive exhaust gas from being supplied to the filter, to prevent cooling of the electric heater and the filter portion of the filter, to supply electric power with the electric heater, and to prevent regeneration failure due to the temperature decrease of the filter due to cooling. Can be prevented.

According to the invention of claim 4, in addition to the effect of the invention of claim 3, the amount of oxygen supplied to the filter in the regenerated state can be finely adjusted by the air replenishing means.

According to the fifth aspect of the invention, since the muffler plays a role of reducing exhaust pulsation, it is not necessary to specially provide a container for reducing exhaust pulsation. Therefore, the space for the container can be saved and the vehicle weight can be reduced. According to the invention described in claim 6, since the exhaust gas hits the container and splits, the exhaust pulsation can be easily reduced, and the container can be made small. In addition, since the containers can be arranged along the left-right direction, the layout can be adapted accordingly.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a first embodiment of an exhaust emission control device for a diesel engine of the present invention.

FIG. 2 is a flowchart showing an operation of switching between collection and regeneration of a filter according to the first embodiment.

FIG. 3 is a configuration diagram showing a second embodiment of an exhaust emission control device for a diesel engine of the present invention.

FIG. 4 is a configuration diagram showing a third embodiment of an exhaust emission control device for a diesel engine of the present invention.

FIG. 5 is a configuration diagram showing a fourth embodiment of an exhaust emission control device for a diesel engine of the present invention.

FIG. 6 is a configuration diagram showing a fifth embodiment of an exhaust emission control device for a diesel engine of the present invention.

FIG. 7 is a configuration diagram showing a sixth embodiment of an exhaust emission control device for a diesel engine of the present invention.

FIG. 8 is a configuration diagram showing a main part of an exhaust emission control device for a diesel engine when the number of pipes and filters is three.

FIG. 9 is a configuration diagram showing a conventional exhaust emission control device for a diesel engine.

[Explanation of symbols]

1 diesel engine 3 exhaust system 5 First piping 6 Second piping 12 First filter device 12B filter 13 Second filter device 13B filter 14 1st on-off valve 16 Second on-off valve 23 Control device 51 First Air Supply Means 53 First air supply means 71 first oxygen supply means 72 First auxiliary combustion supply means

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Naoko Koike             1-chome Ichichome, Ageo City, Saitama NISSAN DI             Within Hazel Industry Co., Ltd. (72) Inventor Hisashi Akakawa             1-chome Ichichome, Ageo City, Saitama NISSAN DI             Within Hazel Industry Co., Ltd. F term (reference) 3G090 AA04 BA04 CB12 CB13 CB15                       CB18 CB27 DA03 DA04 DA13                       DA18 DA20 EA03                 4D058 JA32 KB02 MA42 MA51 QA03                       QA19 SA08

Claims (6)

[Claims] 1. An exhaust pipe provided in the middle of an exhaust system, a plurality of pipes branching from the exhaust pipe and arranged in parallel, and each of which is interposed in the plurality of pipes to collect particulates. A filter, an on-off valve installed on the downstream side of the filters of the plurality of pipes, and an upstream side of the filters of the plurality of pipes or each of the filters, and heating for heating and regenerating each of the filters Means for controlling the ON / OFF state of the heating means and the switching of the open / closed state of the open / close valve to turn off the heating means.
A control device for opening the filter-side on-off valve in the collection state in an open state in synchronization with the state and for closing the filter-side on-off valve in the regeneration state in synchronization with the ON state of the heating means. An exhaust emission control device for diesel engines, which is characterized in that 2. An exhaust pipe provided in the middle of the exhaust system, a plurality of pipes branching from the exhaust pipe and arranged in parallel, and respectively interposed in the plurality of pipes to collect particulates. A filter, an on-off valve that is respectively provided on the downstream side of the filters of the plurality of pipes, an oxygen supply unit that supplies oxygen to each of the plurality of filters, and an upstream side of the filters of the plurality of pipes or the A heating unit mounted on each filter to heat and regenerate each filter, an ON / OFF state switching of the heating unit, and an open / close state switching of the on-off valve are controlled to turn off the heating unit.
A control device for opening the filter-side on-off valve in the collection state in an open state in synchronization with the state and for closing the filter-side on-off valve in the regeneration state in synchronization with the ON state of the heating means. An exhaust emission control device for diesel engines, which is characterized in that 3. An exhaust pipe provided in the middle of an exhaust system, a plurality of pipes branching from the exhaust pipe and arranged in parallel, and respectively interposed in the plurality of pipes to collect particulates. A filter, a container provided on the upstream side of the filter of the exhaust system, an on-off valve interposed on the downstream side of the filter of the plurality of pipes, an upstream side of the filter of the plurality of pipes or each of the filters And heating means for respectively heating and regenerating the respective filters, and switching the ON / OFF state of the heating means and the open / close state of the on-off valve to control the OFF state of the heating means.
A control device for opening the filter-side on-off valve in the collecting state in an open state in synchronization with the state and for making the filter-side on-off valve in the regenerating state in a semi-closed state in synchronization with the ON state of the heating means. Exhaust gas purification device for diesel engines. 4. An exhaust pipe provided in the middle of an exhaust system, a plurality of pipes branched from the exhaust pipe and arranged in parallel, and each of which is interposed in the plurality of pipes to collect particulates. A filter, a container provided on the upstream side of the filter of the exhaust system, an air replenishing unit that is attached to the filter and takes in air from the outside air, and is interposed on the downstream side of the filters of the plurality of pipes, respectively. An on-off valve, a heating unit that is mounted on the upstream side of the filters of the plurality of pipes or on each of the filters and that heats and regenerates each filter, and switches the ON / OFF state of the heating unit and the on-off valve The switching of the open / closed state is controlled to turn off the heating means.
A control device for opening the filter-side on-off valve in the collecting state in an open state in synchronization with the state and for making the filter-side on-off valve in the regeneration state in a semi-closed state in synchronization with the ON state of the heating means. Exhaust gas purification device for diesel engines. 5. The exhaust emission control device for a diesel engine according to claim 3, wherein the container is a muffler. 6. The exhaust emission control device for a diesel engine according to claim 3, wherein the container is arranged over the plurality of pipes.