JP2001248421A - Disel particulate filtering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a diesel particulate filtering device capable of detecting a quantity of particulate substance collected in a filter by a pressure sensor excellent in durability. SOLUTION: A pressure sensor 15, 16, 17 is composed of a casing 44 forming an exhaust gas chamber 56 equipped with an opening 58 for exhaust gas to go in and out, a bellows 45 comprising an elastic member expanding and contracting by an exhaust pressure while being fixed to the casing 44, a plate 46 forming the pressure receiving surface 59 of the exhaust pressure while being fixed to the bellows 45, a light reflector 47 to reflect light while being fixed to the plate 46, a light emitting element 48 to emit light while being fixed to the casing 49, and a displacement detector 50 to detect the quantity of movement L of the plate 46 by reflecting light emitted from the light emitting element 48 by a light reflecting surface 60.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for collecting particulate matter in exhaust gas with a filter, detecting the amount of the collected particulate matter with a pressure sensor, and collecting a predetermined amount of the collected particulate matter. The present invention relates to a diesel particulate filter device that regenerates a filter by heating and burning a curable substance.

[0002]

2. Description of the Related Art Conventionally, suspended matter, carbon, smoke, HC, SO contained in exhaust gas exhausted from an engine is known.
_As a particulate filter for removing particulates such as _X, a filter having a structure in which ceramic fibers are laminated and a filter having a honeycomb structure made of porous ceramics are known. This type of filter generally regenerates the filter by heating and burning the particulate using a heat source when the particulate is collected and the filter is clogged.

[0003] A diesel particulate filter device is provided with an exhaust pipe communicating with an exhaust manifold of a diesel engine, a pair of branch pipes branched from the exhaust pipe, and attached to each of the branch pipes to capture particulates contained in exhaust gas. A collecting filter, a switching valve that operates to flow exhaust gas to one or both of the branch pipes, a communication pipe that connects the two branch pipes between the switching valve and the filter, and an on-off valve and exhaust gas that opens only during regeneration. And a flow control valve for controlling the flow rate of the fluid. A pressure sensor for detecting the exhaust pressure of the exhaust gas is provided in the exhaust pipe upstream of the filter, and a pressure sensor for detecting the exhaust pressure of the purified exhaust gas is provided in the exhaust pipe downstream of the filter. Is provided. When the switching valve is switched in response to the pressure signal from the pressure sensor to introduce the exhaust gas into one of the branch pipes and block the flow of the exhaust gas into the other branch pipe, the particulate contained in the exhaust gas becomes one-sided. (See, for example, JP-A-11-125109).

[0004]

In a diesel particulate filter device, a pressure sensor is used to detect the amount of particulate matter trapped in the filter, but exhaust gas flows through the pressure sensor itself. Since it is attached to the exhaust pipe, the pressure sensor detects the exhaust heat of the exhaust gas, fine particles contained in the exhaust gas,
O _X, or sensor function is deteriorated by harmful substances such as HC, is a problem that the sensor itself is corrosion occurs. In particular, in a pressure sensor configured using components such as electronic elements, the damage is increased, and there is a problem that the exhaust pressure of exhaust gas cannot be accurately detected. In addition, when air is introduced from the outside to the regenerated filter, an air pump for feeding air to the filter, an air cleaner for purifying the air because the outside air contains dust and dirt,
A water intrusion prevention device or the like for removing moisture from the outside air is required, and the structure becomes complicated, resulting in high costs.

Further, when the diesel particulate filter device is mounted on a vehicle, space is limited in the vehicle, and good mounting properties are required. When a pair of filters constituting a diesel particulate filter device are arranged in parallel in the longitudinal direction, the size in the width direction increases, and a large space is required in the width direction.
There is a problem with the mountability on vehicles. By the way, an automobile equipped with an engine is provided with a muffler of a silencer in order to reduce noise generated by the flow of exhaust gas. The conventional muffler is configured to extend in the longitudinal direction of the vehicle, and is attached to a lower rear portion of the vehicle. Therefore, if the diesel particulate filter device is provided with a muffling effect to suppress exhaust noise, the diesel particulate filter device can be installed at the place where the muffler is attached instead of the conventional muffler, and the mountability to the vehicle can be improved at once. Will be able to solve it.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems. A pair of filters are arranged so as to extend in series in a longitudinal direction, and the filters extending in the longitudinal direction are connected to the longitudinal direction of a vehicle. In order to make it possible to mount the filter in any direction, to make it compact to mount on vehicles, to take in exhaust gas from the exhaust pipe at the time of regeneration of the filter from the outlet side exhaust pipe, and to accurately detect the collection state of particulates by the filter with the pressure sensor, The exhaust gas pressure on the inlet and outlet sides can be properly detected. In particular, when the pressure sensor is installed in the exhaust pipe, the part exposed to the exhaust gas is made of a corrosion-resistant and heat-resistant material. Another object of the present invention is to provide a diesel particulate filter device capable of accurately detecting the exhaust pressure of exhaust gas.

According to the present invention, a particulate matter in exhaust gas is collected by a filter, and the amount of the particulate matter collected by the filter is collected by a pressure sensor provided in an exhaust pipe. In a diesel particulate filter device which measures by detecting the atmospheric pressure and energizes a heater provided in the filter to heat and incinerate the collected particulate matter to regenerate the filter, the pressure sensor comprises: A casing forming an exhaust gas chamber having an opening communicating with the exhaust pipe through which exhaust gas flows, a bellows having one end fixed to the casing and formed of an elastic member that expands and contracts by the exhaust pressure;
A plate, which is fixed to the free end at the other end of the bellows, and constitutes a pressure-receiving surface for receiving the exhaust pressure, the casing, the bellows, an air chamber enclosed by the plate and the exhaust gas, and disposed in the air chamber. A light reflecting plate having a light reflecting surface for reflecting the reflected light, a light emitting element disposed in the air chamber so as to face the light reflecting surface and emitting light to the light reflecting surface, and emitting light with the light emitting element. A displacement detector for detecting the amount of movement of the plate by reflecting light on the light reflecting surface.

The light emitting element is fixed to the casing in the air chamber, and the light reflecting plate is fixed to the plate in the air chamber.

The casing, which is exposed to the exhaust gas,
The bellows and the plate are made of a material having high heat resistance and corrosion resistance.

The casing is mounted on the exhaust pipe via a mounting support provided with the opening in the casing.

The casing has a through hole through which air flows in and out according to a change in the volume of an air chamber in the bellows caused by expansion and contraction of the bellows, and a filter for purifying the air is provided in the through hole. Is provided. If no through-hole is provided in the casing, it is of course unnecessary to provide a filter.

The displacement amount detector is connected to a controller through an energizing terminal, and the controller calculates the exhaust pressure of the exhaust gas based on the amount of movement from the displacement amount detector.

The exhaust pipe downstream of the filter on which the pressure sensor is installed is provided with a throttle section for restricting the flow of the exhaust gas in order to properly generate exhaust pressure in an area where the pressure sensor is installed. Is provided.

The filter is disposed in a filter housing having an exhaust gas inlet and an outlet formed opposite to each other in the longitudinal direction, and a distribution housing is interposed between the filter housings. The housing is formed with a distribution chamber in which the inlet of the filter housing opens.

The diesel particulate filter device is connected to the switching on-off valve which is switched to open one of the inlets of the filter housing and closes the other, and is connected to the outlet of the filter housing and merges with each other. An outlet-side exhaust pipe, an EGR pipe connecting the outlet-side exhaust pipe to the filter housing, and a part of the exhaust gas flowing through the outlet-side exhaust pipe at the time of regeneration of the filter through the EGR pipe. E to supply the filter housing
A switching valve provided in a GR pipe, an EGR pump operated to supply the exhaust gas to one of the filter housings through the EGR pipe, and the heater and the heater in response to a detection signal of the pressure sensor. The switching valve,
A controller is provided for controlling the operation of the EGR pump and the switching valve.

The exhaust pipe for discharging the exhaust gas from the filter is formed of an outlet exhaust pipe extending straight from one filter housing and an outlet exhaust pipe extending curved from the other filter housing. In order to adjust the exhaust pressure of the exhaust gas discharged to the outlet side exhaust pipe to be equal to each other, a throttle is provided in the straight outlet side exhaust pipe.

The straight outlet side exhaust pipe and the curved outlet side exhaust pipe merge into one exhaust pipe.

The controller includes a pressure value P ₁ detected by the pressure sensor disposed in the exhaust pipe on the upstream side of the filter and the pressure sensor disposed in the exhaust pipe on the downstream side of the filter. in the case the pressure ratio P ₁ / P ₂ between the detected pressure value P ₂ is equal to or greater than the predetermined value, in a collection completion status has been reached collection amount of the particulate material to one of said filter predetermined Is detected, and the E
The operation of the GR pump is stopped, and the switching valve is switched between the switching valve and the switching valve to control the exhaust gas to flow to the other filter.

As described above, in this diesel particulate filter device, even if the pressure sensor is installed in the exhaust pipe, the portion exposed to the exhaust gas is limited to the surfaces of the casing, the bellows, and the plate. Since the plate only displaces in response to this, if these parts are made of a material with high heat resistance and corrosion resistance, the parts that constitute the electronic element inside the pressure sensor with the exhaust gas will be exhaust gas. The exhaust pressure of the exhaust gas can be always accurately detected without corrosion, and the casing, bellows and plate are not corroded. it can. In the case of a conventional pressure sensor using a piezoelectric element, the pressure sensor itself is contaminated with exhaust gas and cannot be accurately detected. However, the pressure sensor of the present invention uses clean air shielded from exhaust gas. Since the reflection of light is used in the chamber, the air chamber and the reflecting surface are not contaminated with the exhaust gas. The amount can always measure the exhaust pressure with high accuracy.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a diesel particulate filter device according to the present invention will be described below with reference to the drawings. FIG. 1 is a schematic explanatory view showing one embodiment of a diesel particulate filter device according to the present invention,
2 is a sectional view showing an embodiment of the pressure sensor.

This diesel particulate filter device has a function of collecting particulate matter such as carbon, HC and soot contained in exhaust gas discharged from a diesel engine and purifying the exhaust gas. Exhaust pipe 10 connected to the exhaust manifold
It is built in and installed. In this diesel particulate filter device, a pair of filter housings 1 and 2 and a distribution housing 3 interposed between the filter housings 1 and 2 are arranged so as to extend in the longitudinal direction. The pair of filter housings 1 and 2 and the distribution housing 3 extend in the longitudinal direction as a whole, and are formed so that they can be mounted instead of the muffler in a space where the muffler is mounted on the vehicle.

The distribution housing 3 has an exhaust pipe 10 on the inlet side.
The filter outlet 28 of the filter housing 1 is connected to the curved outlet side exhaust pipe 4, and the filter outlet 29 of the filter housing 2 is connected to the straight outlet side exhaust pipe 5. The curved outlet side exhaust pipe 4 and the straight outlet side exhaust pipe 5 join the outlet side exhaust pipe 11 at a junction 31. A pair of filter housings 1 and 2 have filter inlets 8 and 9 to which exhaust gas is supplied, opposed to each other, and filter outlets 28 and
29 are disposed in the longitudinal direction so as to be located on the opposite side. The distribution housing 3 is arranged between the filter housings 1 and 2 to form a distribution chamber 32 in which the filter inlets 8 and 9 are respectively opened, and the exhaust pipe 10 on the inlet side is connected.

The diesel particulate filter device includes filter bodies 24 and 25 disposed in the filter housings 1 and 2 for collecting particulates in exhaust gas, and particles provided on the filter bodies 24 and 25, respectively. Either one of the filter inlets 8 and 9 is opened to supply exhaust gas to a pair of filters 1F, 2F, and the filters 1F and 2F having heaters 26 and 27 made of a wire mesh or the like for heating and burning the curate, and the other is opened. The switching valve 12, which is switched to close the other filter inlets 8, 9 while sitting on valve seats 33, 34 provided at the filter inlets 8, 9, the exhaust pipe 11 on the outlet side and the filter housings 1, 2, Exhaust gas flowing through the exhaust pipe 11 at the time of regeneration of the EGR pipes 6, 7A, 7B and the filters 1F, 2F, respectively. Is switched to one of the EGR pipes 7A and 7B through the EGR pipe 6, and the switching valve 13 provided in the EGR pipe 6 and one of the filter housings 1 and 2 through the EGR pipe 6. It comprises an EGR pump 14 provided in the EGR pipe 6 which is operated to supply exhaust gas. In addition, the switching valve 12 and the switching valve 13 include a position sensor that detects which side the open state is set to. EGR
The pipe 7A is connected to the inlet 8A of the filter housing 1,
The EGR pipe 7B is connected to the inlet 9 of the filter housing 2.
Connected to A. Further, the EGR pipe 6, a pressure sensor 17 for detecting the EGR pressure P ₃ of the EGR gas.

The filters 1F and 2F are filter housings.
Particles contained in the exhaust gas arranged in the
Filter bodies 24 and 25 for collecting rate, filter book
On the upstream and downstream surfaces of the exhaust gas of the bodies 24 and 25
A wire mesh having one of the heaters 26 and 27
It is composed of Filter bodies 24 and 25 are pleated
Folded into a cylindrical shape as a whole,
At both ends of the main bodies 24 and 25, shielding plates 40 and 41 are provided.
Is attached. The shielding plate 40 includes the filter 1F,
The entire surface on the entrance side of 2F is shielded, and the shielding plate 41 is
Inner exhaust gas passages 38, 39 on the outlet side of filters 1F, 2F
The portion excluding the region that constitutes is closed. filter
The main bodies 24 and 25 are made of heat-resistant and oxidation-resistant SiC,
Al_TwoO _Three, SiC coated Si_ThreeN_FourConsisting of
Made from ceramic fiber non-woven fabric and other uniform materials
Materials such as ceramic woven cloth and ceramic felt
Can be made from fiber materials. For fiber material, use single-length fiber material.
Not only can be used, but also
Is a nonwoven fabric laminated with crimped ceramic long fibers, or
Shall be a composite material of crown feathered fibers and / or crimped ceramic.
It can be composed of non-woven fabric laminated with Mick long fiber.
Wear.

The exhaust pipe 10 on the inlet side is provided with a pressure sensor 15 for detecting the exhaust pressure P ₁ of the exhaust gas supplied to the filter 1F or 2F. The exhaust pipe 11 on the outlet side, the pressure sensor 16 for detecting the exhaust pressure P ₂ of the exhaust gas discharged from the filter 1F or filter 2F is provided. The outlet side exhaust pipe 11 downstream of the pressure sensor 16 is provided with a restrictor valve 22 for restricting the flow of exhaust gas in order to properly detect the exhaust pressure P _{2 in the} area where the pressure sensor 16 is installed. . The throttle valve 22 can be configured to adjust the throttle in order to adjust the passage area. Whether or not the particulate matter has been trapped to the limit by the filters 1F and 2F depends on the exhaust pressure in the limit collection state depending on the flow rate of the exhaust gas. Exhaust pressure P ₁ , P
By calculating the _second pressure ratio P ₁ / P _2, to detect the limit collecting state of particulates materials by the filter 1F, 2F. The flow rate of the exhaust gas filter 1F, 2F outlet side increases and the exhaust pressure P ₂ increases, the filter 1F, during 2F regeneration, exhaust pressure P ₂ is E
Helps the GR pump 14.

In this diesel particulate filter device, the exhaust gas discharged from the filter housing 2 through the straight outlet-side exhaust pipe 5 and the exhaust gas discharged from the filter housing 1 through the curved outlet-side exhaust pipe 4. A throttle 23 is provided in the straight outlet side exhaust pipe 5 in order to adjust the respective exhaust pressures of the exhaust gas and the exhaust gas to be equal to each other. In FIG. 1, in order to adjust the exhaust pressure discharged from the filter housing 1 and the filter housing 2 to be equal to each other, a throttle 23 is provided at the filter outlet 29.
However, the diameter of the curved exhaust-side exhaust pipe 4 bypassing the filter outlet 28 and connected to the exhaust pipe 11 is increased so that the same function as the throttle 23 can be achieved. It can also be adjusted by reducing the diameter of the side exhaust pipe 5.

The controller 20 includes filters 1F, 2F
, An actuator 30 for operating the switching valve 12, and a switching valve 1 provided for the EGR pipe 6.
3 and a motor 35 for driving the EGR pump 14 are controlled in response to detection signals from the pressure sensors 15, 16, 17 for detecting the particulate collection state by the filters 1F, 2F. The motor 35 that drives the EGR pump 14
In order to adjust the EGR gas containing air required for regeneration of the filters 1F and 2F in accordance with the operating condition of the engine, the controller 20 is configured to control the rotation speed. The operating condition of the engine is detected by a rotation sensor 42 for detecting engine rotation and a load sensor 43 for detecting engine load. In some cases, the controller 20 may be configured to control each device according to a detection signal of a temperature sensor provided in the exhaust pipe 10 on the upstream side of the filters 1F and 2F to detect an exhaust gas temperature. In this case, the exhaust gas temperature is correlated with the magnitude of the engine load, and the higher the engine load and the higher the exhaust gas temperature, the lower the O ₂ concentration.

As shown in FIG. 2, the pressure sensors 15, 16, and 17 each have a casing that forms an exhaust gas chamber 56 that communicates with the exhaust pipes 10 and 11 through which exhaust gas flows and the EGR pipe 6 that is an exhaust pipe through an opening 58. Bellows 45, which are made of an elastic member which expands and contracts by the exhaust gas pressure of an exhaust gas chamber 56, one end of which is fixed to the casing 49 at the joint portion 61, receives the exhaust pressure fixed to the other free end of the bellows 45. A plate 46 forming a pressure receiving surface 59, a light reflecting plate 47 having a light reflecting surface 60 fixed to the plate 46 and reflecting light, a light emitting element 48 fixed to the casing 49 and emitting light to the light reflecting surface 60, and The light-emitting element 48 includes a displacement detector 50 that reflects the light emitted from the light-emitting element 48 on the light reflecting surface 60 to detect the displacement L of the plate 46.
The casing 49 is fixed to the casing 44 to form an exhaust gas chamber 56, and includes an energizing terminal 55 for connecting the displacement detector 50 to the controller 20.

The displacement detector 50 is a photo-interrupter that constitutes a kind of position sensor. The displacement detector 50 reliably performs light shielding and light transmission between the light emitting element 48 and the light reflecting surface 60, and receives light from the light reflecting surface 60. The plate 46 receives the reflected light.
Can be accurately detected, and a bypass capacitor can be incorporated in the power supply unit to prevent noise. The casings 44 and 49, the bellows 45, and the plate 46 exposed to the exhaust gas are made of a material having high heat resistance and corrosion resistance, for example, a thin plate of stainless steel. The bellows 45 can be made of an elastic material such as stainless steel, brass, beryllium copper, phosphor bronze, etc., which has proper expansion and contraction characteristics depending on the acting force. Is preferable. The casing 44 is connected to the exhaust pipes 10 and 11 and the EGR via a mounting support 57 having an opening 58 provided therein.
Attached to tube 6. Since the displacement amount detector 50 does not have heat resistance, it is preferable to attach the displacement amount detector 50 to the casing 49 via a heat shield. The casing 49 has through holes 5 through which air flows in and out according to a change in the volume of the air chamber 62 in the bellows 45 caused by expansion and contraction of the bellows 45.
2 are formed. Further, the casing 49 having the through hole 52 is provided with a filter cylinder 63 containing a filter 53 for purifying air flowing into and out of the air chamber 62 through the through hole 52. A cover 54 is provided on the filter cylinder 63. The displacement amount detector 50 is connected to the controller 20 through a power supply terminal 55.
Although not shown, it is a matter of course that the casing 49 can be configured to have no through hole.

The controller 20 is configured to calculate the exhaust pressures P ₁ , P ₂ , and P ₃ of the exhaust gas in response to the detected value of the displacement L of the plate 46 from the displacement detector 50. Needless to say, the displacement detector 50 detects the displacement L as the exhaust pressure P.
_The detection values calculated for ₁ , P ₂ and P ₃ may be sent to the controller 20 as signals. As described above, the pressure sensors 15, 16, and 17 are configured such that the portions exposed to the exhaust gas are the casings 44 and 49 and the bellows 45.
And the pressure of the exhaust gas P
Since only the plate 46 is displaced in position upon receiving ₁ , P ₂ and P ₃ , the casings 44 and 49 and the bellows 45
If the surfaces of the plate 46 and the plate 46 are made of a material having high heat resistance and corrosion resistance, they are not corroded by the exhaust gas, and the light emitting element 48 and the light reflection plate inside the pressure sensor are not affected by the exhaust gas. 47, the portion constituting the electronic device such as a displacement detector 50 without being exposed to the exhaust gas, also without functions by contamination by exhaust gas is lowered, always exactly exhaust gas exhaust pressure P ₁ , P ₂ ,
P ₃ can be detected, it is possible to improve the durability.

This diesel particulate filter device collects particulates such as carbon, soot, and HC contained in exhaust gas that alternately passes through the filters 1F and 2F, and collects the particulates collected by the filters 1F and 2F. Then, the heaters 26 and 27 of the upstream wire mesh or the downstream wire mesh are energized from the power supply through the power supply terminal 18 to heat and incinerate the particulate matter and regenerate the filters 1F and 2F. Further, in this diesel particulate filter device, the exhaust sound or noise generated by the flow of exhaust gas is such that the exhaust gas flows into the distribution housing 3 from the exhaust pipe 10 and expands. The filter 1F, which is further expanded and flows into the housings 1 and 2 and set in the filter housings 1 and 2,
The sound is silenced by flowing to the curved outlet side exhaust pipe 4, the straight outlet side exhaust pipe 5 and the exhaust pipe 11 through the 2F.

The EGR pipe 6 is connected to the exhaust pipe 11,
An EGR pump 14 is provided for supplying the purified exhaust gas to the filters 1F and 2F through the EGR pipe 6. The EGR pump 14 is driven by a DC motor 35 with DC power supplied from a battery or a generator 21, and the DC motor 35 is configured such that the rotation speed is controlled by the controller 20 according to the operating condition of the engine. . Although not shown, the EGR pump 14 partitions a housing that forms a pump chamber, a rotary shaft eccentrically and rotatably mounted in the housing, and a pump chamber formed by the housing and the rotary shaft into a plurality of compartments. Therefore, it is constituted by vanes biased by a spring force which are respectively arranged so as to be able to reciprocate in the axial direction of the rotating shaft. In addition, the filters 1F, 2
The EGR gas pressure of the EGR gas supplied to F is detected by the pressure sensor 17 and controlled so that appropriate EGR gas is supplied to the filters 1F and 2F.

Further, in order to heat and incinerate the particulates collected in the filter bodies 24 and 25 of the filters 1F and 2F, an upstream wire mesh or a downstream wire mesh as heaters 26 and 27 provided in the filters 1F and 2F, respectively. Is provided. Between the filter housings 1 and 2 and the filter bodies 24 and 25, the outer exhaust gas passages 36, into which the exhaust gas flowing from the filter inlets 8, 9 expand and enter.
37 are formed. Also, the filter bodies 24, 25
Inside are formed inner exhaust gas passages 38 and 39 into which the purified exhaust gas passing through the filter bodies 24 and 25 from the outer exhaust gas passages 36 and 37 enters.

The controller 20 includes the filter 1
F, when 2F playback, so the amount of O ₂ in the EGR gas supplied filter 1F, the 2F (exhaust gas) becomes uniform, detected by the temperature sensor 19 provided upstream of the filter 1F, 2F The rotation speed of the DC motor 35 is controlled according to the detected value of the exhaust gas temperature. Further, during regeneration of the filters 1F and 2F, the controller 20 increases the rotation speed of the motor 35 when the load of the engine is high, sends a large amount of exhaust gas to the filters 1F and 2F, and reduces the rotation speed of the motor 35 when the load is low. Filter 1F, 2F
A small amount of exhaust gas is set to be controlled. The controller 20 includes filters 1F, 2F
The heaters 26 and 27 are energized in response to the collection of particulates equal to or more than a predetermined amount, and the particulate matter collected by the filters 1F and 2F is heated and incinerated to filter the filters 1F and 2F. Is controlled to be played.

Since the diesel particulate filter device is configured as described above, it operates as follows. By the operation of the diesel engine, the switching valve 12 opens the filter inlet 8 of the filter housing 1 and closes the filter inlet 9 of the filter housing 1 as shown in FIG. 1, for example. Exhaust gas from the diesel engine flows from the exhaust manifold through the exhaust pipe 10 into the distribution chamber 32, and from the filter inlet 8 of the filter 1F through the outer exhaust gas passage 26, the filter 1F, and the inner exhaust gas passage 38 to form a curved outlet exhaust pipe. 4. Then, the exhaust gas is discharged to the exhaust pipe 11, and the suspended fine particles, that is, the particulate matter contained in the exhaust gas are collected by the filter 1F.

The exhaust pressure signals from the pressure sensors 15 and 16 are input to the controller 20, and the controller 20 calculates the pressure ratio between the exhaust gas pressure on the upstream side and the exhaust gas pressure on the downstream side of the filter 1F. Filter 1F is clogged, ie, filter 1F
When particulate materials deposited on reaches a predetermined amount, the pressure ratio P ₁ / P ₂ of the exhaust pressure P _1, P ₂ of the exhaust gas between the upstream side and the downstream side of the filter 1F has reached a predetermined value. When the pressure ratio P ₁ / P ₂ reaches a predetermined value, the actuator 30 is actuated by a command from the controller 20, the switching valve 12 is switched (the side indicated by the dotted line in FIG. 1), and the exhaust gas from the diesel engine is exhausted. Through the exhaust pipe 10, from the filter inlet 9 of the filter housing 2, through the outer exhaust gas passage 37, the filter 2F and the inner exhaust gas passage 39 to the straight outlet exhaust pipe 5, and then the exhaust pipe 11
And the particulate matter contained in the exhaust gas is collected by the filter 2F.

While the exhaust gas is flowing into the filter 2F, since the flow of the exhaust gas is blocked by the switching valve 12 on the filter 1F side, the controller 20 releases O ₂ for regenerating the filter 1F. Exhaust gas containing EG
In order to supply R gas to the filter 1F, the EGR pump 1
4 is operated, the switching valve 13 is switched, and the EG
The gas is sent from the R pipe 6 through the EGR pipe 7A to the outside exhaust gas passage 36 from the EGR inlet 8A. Wire mesh heater 26
To make it function as a heater, and heat and incinerate the particulate matter collected in the filter 1F. When the wire mesh heater 26 of the filter 1F is energized and the energization time reaches a predetermined time, the temperature of the filter main body 24 reaches a temperature at which the particulate matter can be burned, and the filter 1F
The particulate matter trapped in the filter is heated and incinerated, and the filter 1F is regenerated.

When the exhaust gas continues to flow into the filter 2F, the filter 2F eventually becomes clogged. Particulate materials deposited on the filter 2F reaches a predetermined amount, the pressure ratio P ₁ / P ₂ of the exhaust pressure P _1, P ₂ of the exhaust gas between the upstream side and the downstream side of the filter 2F reaches a predetermined value. When the pressure ratio reaches a predetermined value, the switching valve 12 is switched by the operation of the actuator 30 according to a command from the controller 20, and the exhaust gas from the diesel engine flows into the filter 1F again through the exhaust pipe 10. . Therefore, while the exhaust gas is flowing into the filter 1F, the flow of the exhaust gas into the filter 2 is blocked, so that the filter 2F is regenerated during that time. When the wire mesh heater 27 of the filter 2F is energized and the energization time reaches a predetermined time and the temperature reaches a temperature at which the particulate matter can be burned, the particulate matter collected by the filter 2F is heated and incinerated, 2F is reproduced.

[0039]

Since the diesel particulate filter device according to the present invention is constructed as described above, the pressure sensor does not become polluted or corroded by the exhaust gas, the detection function is not deteriorated, and the exhaust pressure of the exhaust gas is reduced. Detection can always be performed with high accuracy, and reliable control can be secured. In addition, when this diesel particulate filter device is mounted on a vehicle, it is mounted in a space where the muffler is to be mounted on the vehicle instead of the muffler,
Along with the installation in the longitudinal direction of the vehicle, the installation to the vehicle is improved, and a straight exit-side exhaust pipe is provided with a throttle to ensure uniformity with the exhaust pressure of the curved exit-side exhaust pipe. Further, a throttle valve is provided on the outlet side exhaust pipe, and by always detecting the pressure ratio between the exhaust pressure in the exhaust pipe on the upstream side of the filter and the exhaust pressure in the exhaust pipe on the downstream side, the particulate matter of the filter is reduced. It is configured to accurately detect the collection state and control collection and regeneration appropriately.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing one embodiment of a diesel particulate filter device according to the present invention.

FIG. 2 is a sectional view showing a pressure sensor incorporated in the diesel particulate filter device of FIG.

[Explanation of symbols]

 1, 2 filter housing 1F, 2F filter 3 distribution housing 4 curved outlet side exhaust pipe 5 straight outlet side exhaust pipe 6, 7A, 7B EGR pipe 10 inlet side exhaust pipe 11 outlet side exhaust pipe 12 switching on / off valve 13 switching valve 14 EGR pump 15, 16, 17 Pressure sensor 20 Controller 22 Throttle valve 23 Throttle 24, 25 Filter body 26, 27 Wire mesh heater 32 Distribution chamber 36, 37 Outer exhaust gas passage 38, 39 Inner exhaust gas passage 44, 49 Casing 45 Bellows 46 plate 47 light reflecting plate 48 light emitting element 50 displacement detector 52 through hole 53 filter 55 conducting terminal 56 exhaust gas chamber 57 mounting support part 58 opening 59 pressure receiving surface 60 light reflecting surface 61 joining part 62 air chamber 63 filter cylinder

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B01D 46/42 B01D 46/42 B G01L 7/06 G01L 7/06 9/00 9/00 B

Claims (12)

[Claims] A filter collects particulate matter in exhaust gas by a filter, and measures the amount of the particulate matter collected in the filter by a pressure sensor provided in an exhaust pipe. In a diesel particulate filter device that regenerates the filter by heating and burning the collected particulate matter by energizing a heater provided in the filter, the pressure sensor is configured to detect the exhaust gas. A casing forming an exhaust gas chamber having an opening communicating with the exhaust pipe through which gas flows, a bellows having one end made of an elastic member fixed to the casing and expanding and contracting by the exhaust pressure, and a free end at the other end of the bellows. A plate, a casing, the bellows, and the plate forming a pressure receiving surface receiving the fixed exhaust pressure; An air chamber cut off from the exhaust gas surrounded by the light chamber, a light reflecting plate having a light reflecting surface for reflecting light disposed in the air chamber, and disposed in the air chamber so as to face the light reflecting surface and the light. A light emitting element for emitting light to a reflecting surface, and a displacement detector for detecting the amount of movement of the plate by reflecting the light emitted by the light emitting element on the light reflecting surface. Diesel particulate filter device. 2. The diesel particulate filter according to claim 1, wherein the light emitting element is fixed to the casing in the air chamber, and the light reflecting plate is fixed to the plate in the air chamber. apparatus. 3. The diesel particulate according to claim 1, wherein the casing, the bellows, and the plate exposed to the exhaust gas are made of a material having high heat resistance and corrosion resistance. Filter device. 4. The diesel particulate filter device according to claim 1, wherein the diesel particulate filter device is attached to the exhaust pipe via an attachment support provided with the opening provided in the casing. 5. A through hole is formed in the casing to allow air to flow in and out according to a change in the volume of the air chamber in the bellows caused by expansion and contraction of the bellows. The through hole purifies the air. The diesel particulate filter device according to claim 1, further comprising a filter. 6. The displacement amount detector is connected to a controller through an energizing terminal, and the controller calculates the exhaust pressure of the exhaust gas in response to the displacement amount signal from the displacement amount detector. The diesel particulate filter device according to claim 1, wherein 7. An exhaust pipe provided on the downstream side of the filter on which the pressure sensor is installed, the throttle having a throttle action on the flow of the exhaust gas in order to appropriately generate exhaust pressure in an area where the pressure sensor is installed. The diesel particulate filter device according to claim 1, wherein a portion is provided. 8. The filter is disposed in a filter housing having an exhaust gas inlet and an outlet formed opposite to each other in a longitudinal direction, and a distribution housing is interposed between the filter housings. 2. The diesel particulate filter device according to claim 1, wherein the distribution housing has a distribution chamber in which an inlet of the filter housing is opened. 3. 9. A switching valve which is switched to open and close one of the inlets of the filter housing and an outlet-side exhaust pipe connected to the outlet of the filter housing and merging with each other, An EGR pipe that connects an outlet-side exhaust pipe to the filter housing, and a part of the exhaust gas flowing through the outlet-side exhaust pipe during regeneration of the filter is supplied to one of the filter housings through the EGR pipe. A switching valve provided on the EGR pipe, an EGR pump operated to supply the exhaust gas to one of the filter housings through the EGR pipe, and a detection signal from the pressure sensor. A controller for controlling the operation of the heater, the switching valve, the EGR pump, and the switching valve; 9. The method according to claim 8, wherein
2. The diesel particulate filter device according to item 1. 10. An exhaust pipe for discharging the exhaust gas from the filter, the exhaust pipe extending straight from one of the filter housings, and the exhaust pipe extending curved from the other filter housing. The straight exhaust-side exhaust pipe is provided with a throttle to adjust the exhaust pressure of the exhaust gas discharged to the outlet-side exhaust pipe to be equal to each other. The diesel particulate filter device according to claim 9, wherein 11. The diesel particulate filter device according to claim 10, wherein the straight outlet-side exhaust pipe and the curved outlet-side exhaust pipe merge into one exhaust pipe. . 12. The method of claim 11, wherein the controller, the disposed in the exhaust pipe downstream of the detected pressure value P ₁ by the pressure sensor disposed in the exhaust pipe upstream of the filter filter when the pressure ratio P ₁ / P ₂ between the pressure value P ₂ detected by the pressure sensor is higher than a predetermined value, collecting completed reaching the collection amount of the particulate material to one of said filter predetermined 10. The control system according to claim 9, wherein when the state is detected, the operation of the EGR pump is stopped, and the switching valve is switched between the switching valve and the switching valve to control the flow of the exhaust gas to the other filter. 2. The diesel particulate filter device according to item 1.