JP3331919B2 - Exhaust gas purification device for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas purifying apparatus for an internal combustion engine that collects particulates contained in exhaust gas of the internal combustion engine by a particulate filter.

[0002]

2. Description of the Related Art Exhaust gas emitted from an internal combustion engine such as an automobile, particularly a diesel engine, contains particulates (exhaust particulates) mainly composed of carbon. Therefore, in a vehicle equipped with a diesel engine, an exhaust gas purifying device having a ceramic columnar particulate filter (hereinafter, simply referred to as a filter) is provided in an exhaust pipe (exhaust passage) of the diesel engine, and the exhaust gas is filtered by the filter. The collection of particulates inside is performed.

By the way, in a filter, when the collected particulates increase due to accumulation, the air permeability is gradually impaired. Therefore, regeneration of the filter is required. Therefore, in an exhaust gas purifying apparatus for an automobile, the accumulated particulates are incinerated on a filter by a heater, for example, an electric heater (filter regeneration).

An exhaust gas purifying apparatus having such an incineration function uses a structure in which a filter, an electric heater and the like are housed in a case, as shown in Japanese Utility Model Application Laid-Open No. 4-34422.

More specifically, as shown in FIG. 3, for example, an end of the exhaust gas introduction pipe 1 on the outlet side is inserted and connected to one end, and an exhaust gas outlet 2 is formed on the other end. A cylindrical housing case 3 (corresponding to a case) is adopted, and an electric heater 4, for example, a cylindrical honeycomb filter (inflow side) is introduced into the housing case 3 from an inflow side (a side to which the exhaust gas introduction pipe 1 is connected). A structure in which filters 5 each having a passage group in which the side and the outflow side are alternately plugged with plugs) is used is used. 1a is formed only on the peripheral wall of the end inserted into the case of the exhaust gas introduction pipe 1, and accommodates the exhaust gas from the engine in the housing case 3.
Reference numeral 9 denotes an exhaust pipe of a diesel engine.

When the exhaust gas flowing from the inflow end of the filter 5 into the passage 6 with the inflow side open is passed through a thin partition wall between the passage 6 and the passage 7 with the outflow side open, particulates in the exhaust gas are removed. And the purified exhaust gas is discharged through a passage 7 having an open outflow side.

When the filter 5 is regenerated (when the amount of particulates deposited on the filter 5 exceeds a predetermined value), the electric heater 4 is energized for a predetermined time, and the filter 5 is regenerated. The end face is heated to the particulate combustion temperature to ignite the particulate on the inflow end face side, and thereafter, a part of the regeneration gas, for example, the exhaust gas is introduced into the inflow side of the filter 5, and the flame formed inside the filter is removed. This is carried out by propagating the accumulated particulates to the outflow side and burning them in the filter 5.

The heat of the electric heater 4 is transferred to the filter 5.
Easy to escape in the opposite direction. Therefore, as disclosed in the above-mentioned publication, a heat reflecting plate 8 made of ceramics is installed on the upstream side of the electric heater 4 as shown in the above-mentioned publication to suppress the heat loss. The heat that escapes in the opposite direction of the filter 5 when the power is supplied to the filter 5 is stored by utilizing the characteristics of the ceramics, and when the regeneration gas is supplied, the heat is exchanged with the regeneration gas passing through the ceramics to be recovered.

[0009]

During the regeneration process of the filter 5, the most energy is required to ignite the particulates at the inflow end of the filter 5. However, among the heat generated from the electric heater 4, the filter 5
The heat escaping in the opposite direction is recovered by the heat reflecting plate 8 into the regenerated gas, so that the use of the heater heat at the time of ignition of the particulate requiring the most energy was insufficient.

The present invention has been made in view of the above circumstances. It is an object of the present invention to use an internal combustion which can use heater heat escaping in the opposite direction of a filter as energy for igniting particulates requiring the most energy. An object of the present invention is to provide an exhaust gas purification device for an engine.

[0011]

According to a first aspect of the present invention, there is provided an exhaust gas purifying apparatus, comprising: a reflecting plate disposed upstream of a heater; the structure is reflected to the inlet end of the filter and the result DOO
The heat reflection plate is connected to the exhaust gas introduction pipe connected to the case.
The structure is such that it is assembled so as to support the end of the.

Thus, when the heater is energized, the heat of the heater that escapes in the opposite direction of the filter is supplied to the inflow end of the filter by the reflection of the heat reflecting plate. That is, the heater heat that escapes in the opposite direction of the filter is supplied as energy that requires the most energy and ignites the particulates at the filter inlet end.

As a result, the ignitability of the particulate is improved. In addition, the power consumption of the heater for ignition is small. In addition, the heat reflection plate is connected to the exhaust gas introduction pipe.
Simple structure that can be shared as a support member for
The end of the constant exhaust gas introduction pipe can be fixed. The exhaust gas purifying apparatus according to claim 2, wherein the metal heat reflecting plate is made of an aluminum alloy, a copper alloy, a nickel alloy, or a chromium alloy so that the heat reflecting plate is not affected by the exhaust gas and has a high heat reflectance. Or a material such as a zinc alloy or by plating the surface facing the heater with the above material.

[0014] exhaust gas purifying apparatus according to claim 3, passing
In order to reduce the loss of heater heat that escapes from the pores,
On the upstream side of the firing plate, a second air vent with a similar structure
(2) The heat reflection plate is connected to the ventilation holes of the heat reflection plate.
The heat sink that escapes from the ventilation hole of the heat reflection plate
The heat is also reflected to the filter .

[0015]

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described based on a first embodiment shown in FIG. In the exhaust gas purifying apparatus shown in the drawings, the same parts as those described in the above section of "Prior Art" are denoted by the same reference numerals, and the description thereof will be omitted. The main part will be described.

The present embodiment differs from the first embodiment in that a heat reflecting plate 10 for reflecting the heater heat in real time is used instead of a structure in which the heater heat is stored and then reduced. That is, the heat reflection plate 10 is formed of a metal plate member formed in a shape that blocks the inside of the storage case 3, for example, a disk shape.

More specifically, the entire heat reflecting plate 10 is formed of a material such as an aluminum alloy, a copper alloy, a nickel alloy, a chromium alloy, a zinc alloy or the like which provides a high reflectance.
A smooth heat reflecting surface 1 on a surface facing the electric heater 4 for directly reflecting heat from the heater 4 to an inflow side end of the filter 5.
1 is adopted. And, by forming with this material, even if an oxide film is formed on the surface due to contact with the exhaust gas, the heat reflection surface 11 which can maintain a high reflectance is obtained.

As a matter of course, the heat reflecting plate 10 is not formed as a whole with the above-mentioned material in the shape of a disc, but is formed of, for example, a base material formed in a disc shape, for example, an iron plate formed in a disc shape.
The above-mentioned materials, namely, aluminum alloy, copper alloy, nickel alloy, chromium alloy,
The same applies when the heat reflecting surface 11 is formed by plating a material such as a zinc alloy.

Of course, if the surface of the heat reflecting surface 11 is polished (mirror finished), it goes without saying that the material itself exhibits a higher heat reflectance than the material itself provides. A plurality of ventilation holes 12 are formed in the disk portion of the heat reflection plate 10 to rectify the exhaust gas introduced from the exhaust gas introduction pipe 1 to the upstream side of the heat reflection plate 10 to inflow the filter 5. I can lead to the end.

Further, a fixing seat 13 is formed on the outer peripheral portion of the heat reflecting plate 10, for example, by forming the outer peripheral portion of the heat reflecting plate 10 into a short cylindrical shape following the inner surface of the case. The fixing seat 13 is fixed to the inner surface of the case, for example, by welding or the like, and the heat reflecting plate 10 is installed on the upstream side of the electric heater 4.

At the center of the heat reflecting plate 10, for example, a closed insertion end (rear end) of the exhaust gas introducing pipe 1 is fixed by welding or the like. The end of the introduction tube 1 is supported.

The heat reflector 10 allows the most heat to be supplied to the filter 5 when the particulate matter collected by the filter 5 is ignited by the electric heater 4.

That is, for regeneration of the filter 5, the electric heater 4 is energized for a predetermined time to heat the inflow side end face of the filter 5 to the particulate combustion temperature, and then a part of the regeneration gas, for example, the exhaust gas is filtered. 5 to the inlet side.

At this time, the particulates are ignited by the heater heat A directly from the electric heater 4 to the inflow end of the filter 5 and reflected by the heat reflection surface 11 of the heat reflection plate 10 toward the inflow end of the filter 5. This is performed by heating the incident end face of the filter 5 to the particulate combustion temperature with the heater heat B escaping in the opposite direction of the filter 5.

Thus, the heat of the heater escaping in the opposite direction of the filter 5 can be used as energy for igniting the particulates at the inflow end of the filter, which requires the most energy.

That is, the amount of heat supplied to the end face of the filter 5 increases. Therefore, the ignitability of the particulates can be improved. In particular, the heat reflecting plate 10 is made of a material such as an aluminum alloy, a copper alloy, a nickel alloy, a chromium alloy, or a zinc alloy that promises heat reflection at a high heat reflectance without being affected by exhaust gas, or a material such as an iron plate. Since the base material is formed by plating with the above-mentioned material, it is possible to always expect high particulate ignitability.

In addition, the power consumption of the electric heater 4 can be reduced by increasing the amount of heat supplied to the end face of the filter 5. In addition, since the heat reflection plate 10 is made of metal, the heat reflection plate 10 is cheaper than a heat reflection plate made of ceramics, and can be easily attached to the storage case 3. In addition, the thickness of the heat reflection plate 10 can be reduced, which contributes to downsizing of the exhaust gas purification device.

Further, since the end portion (rear end) of the exhaust gas introduction pipe 1 is supported by the metal heat reflection plate 11, the heat reflection plate 10 can be shared as a supporting member of the exhaust gas introduction pipe 1. With the structure, the end of the unstable exhaust gas introduction pipe 1 can be fixed.

FIG. 2 shows a second embodiment of the present invention.
In the present embodiment, the heat reflection plate 1 is provided upstream of the heat reflection plate 10.
A heat reflection plate 15 (corresponding to a second heat reflection plate) having the same structure as that of
Vent hole 12 of heat reflecting plate 10 and vent hole 12 of heat reflecting plate 15
And the heater heat C passing through the vent hole 12 of the heat reflecting plate 10 on the side close to the electric heater 4.
Is reflected by the heat reflecting plate 15 on the side farther from the electric heater 4.

Such a structure in which the heat reflecting plates are arranged in a double manner can reduce the loss of the heater heat C escaping from the air holes 12, and can expect efficient heat reflection while ensuring sufficient air permeability. In FIG. 2, the same parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

[0032]

As described above, according to the first aspect of the present invention, when the heater is energized, the heater heat escaping in the opposite direction of the filter is supplied to the inflow end of the filter by the reflection of the heat reflecting plate. Therefore, the heater heat that escapes in the opposite direction of the filter can be used as the energy for igniting the particulates that require the most energy.

As a result, the ignitability of the particulates can be improved, and the power consumption of the heater for ignition can be reduced. In addition, since the heat reflection plate is made of metal, the heat reflection plate is inexpensive and can be easily attached to the storage case.

In addition, the thickness of the heat reflecting plate can be reduced, which contributes to downsizing of the exhaust gas purifying apparatus . further,
Use the heat reflector as a support member for the exhaust gas introduction pipe
With a simple structure, the end of the unstable exhaust gas introduction pipe
This has the effect of being able to be fixed . According to the second aspect of the invention, in addition to the effects of the first aspect of the invention, it is possible to obtain a heat reflection plate having a high heat reflectance which is not affected by the exhaust gas, and always has high particulate ignition. Sex can be expected.

According to the invention described in claim 3, according to claim 1
In addition to the effects of the invention described in the above, escape from the vent of the heat reflection plate
Heater heat loss and sufficient air permeability
And a high rate of good heat reflection action can be obtained .

[0036]

[Brief description of the drawings]

FIG. 1 is a side sectional view showing a structure of an exhaust gas purifying apparatus according to a first embodiment of the present invention.

FIG. 2 is a side sectional view showing the structure of an exhaust gas purification device according to a second embodiment of the present invention.

FIG. 3 is a side sectional view for explaining the structure of a conventional exhaust gas purification device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Housing case (case) 4 ... Electric heater (heater) 5 ... Particulate filter 9 ... Exhaust pipe (exhaust path of an internal combustion engine) 10 ... Heat reflection plate 11 ... Heat reflection surface 12 ... Vent hole 15 ... 2nd heat reflection Board.

──────────────────────────────────────────────────続 き Continued from the front page (56) References JP-A-9-125934 (JP, A) JP-A 5-69313 (JP, U) JP-A 6-28216 (JP, U) JP-A 4-28313 34422 (JP, U) Special Table Sho-61-500861 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F01N 3/02

Claims (3)

(57) [Claims] 1. A case provided in an exhaust passage of an internal combustion engine, a particulate filter housed in the case for collecting particulates in exhaust gas, and a filter for heating an inflow-side end face of the particulate filter. A heater for regeneration, a heat reflection plate disposed upstream of the heater in the case, and a heat reflection plate positioned upstream of the heat reflection plate and connected to the case.
Exhaust gas introduction pipe, and the case provided only on the peripheral wall of the exhaust gas introduction pipe
In the exhaust gas purifying apparatus for an internal combustion engine having an exhaust gas outlet for leading out exhaust gas into the inner, the heat reflecting plate has a vent made of metal, the surface facing the heater from the heater The heat reflecting plate is configured to reflect heat directly to the inflow-side end of the filter , and the heat reflection plate supports an end of the exhaust gas introduction pipe.
An exhaust gas purifying apparatus for an internal combustion engine, wherein the exhaust gas purifying apparatus is assembled so as to be held. 2. The heat reflecting plate is made of an aluminum alloy, a copper alloy,
2. The exhaust gas purification of an internal combustion engine according to claim 1, wherein the exhaust gas purification is made of a material such as a nickel alloy, a chromium alloy, a zinc alloy or the like, or a surface facing the heater is plated with the material. apparatus. 3. A heat-reflecting second heat- reflecting plate having a ventilation hole is disposed upstream of the heat- reflecting plate in the case so that the positions of the heat-reflecting plate and the vent hole are shifted from each other. 2. The exhaust gas purifying apparatus for an internal combustion engine according to claim 1, wherein: