JPH0711934A - Diesel particulate filter - Google Patents

Abstract

PURPOSE:To vacuum evaporate TiC on a non-conductive, porous filter composed of comparatively cheap materials so as to make it conductive and at incinerating deposits, directly connect electricity to a filter to burn the deposites. CONSTITUTION:A filter block 2 formed by laminating a plurality pairs of non- conductive porous ceramics bodies 22 and porous ceramics 21 made to be conductive by vacuum evaporating TiC thereon is stored in the central part 12 of a filter case 1 and the porous ceramics 21 is directly energized by electricity to heat the whole filter block 2 so that deposits caught by passing exhaust gas through are subjected to burning treatment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diesel particulate filter for collecting particulates in exhaust gas of a diesel engine.

[0002]

2. Description of the Related Art In a diesel engine, fuel is injected into high-temperature air by adiabatic compression, and the combustion is carried out. Since it is a heterogeneous combustion, the emission of carbon monoxide and hydrocarbons is small, but Nitrogen oxides and particulates
There is a problem that a large amount of waste is emitted.

In order to prevent the release of such particulates to the atmosphere, a particulate filter has been developed which is equipped with a filter in the exhaust passage to filter the exhaust gas and purify it.

[0004]

In order to make such a particulate filter with a relatively inexpensive material,
The heat-resistant ceramics filter having a urethane foam-like or pumice-like porous structure may be formed of a material such as Al2 O3, mullite or cordierite.

However, since this kind of material is non-conductive, it is not possible to energize the filter itself to incinerate the carbon particles collected by the filter, and when the incineration process is performed by heating with electric heat, There is a problem that the cost is increased because it takes time to embed the heating wire in the filter.

The present invention is intended to solve such a problem, and its purpose is to make a filter made of the above-mentioned material conductive so that it can be heated by directly energizing it when incinerating a deposit. -To provide a filter.

[0007]

In order to achieve the above object, according to the present invention, there is provided a diesel particulate filter for collecting particulates in exhaust gas of a diesel engine and incinerating the particulates by electric heat. A plurality of sets of a filter layer formed of a porous body using a heat-resistant and non-conductive material and a filter layer having conductivity by depositing TiC on the porous filter layer are laminated. There is provided a diesel particulate filter which allows exhaust gas to pass through in a direction perpendicular to the stack and energizes the conductive filter layer to incinerate it.

[0008]

The porous filter layer is formed of a relatively inexpensive heat-resistant and non-conductive material, and TiC is vapor-deposited to make the filter conductive. When incinerating the deposit collected by filtering the exhaust gas with the body, the conductive layer can be directly energized to facilitate the treatment.

[0009]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a block diagram showing the construction of an embodiment of a diesel particulate filter according to the present invention. In the figure, 1 is a filter case, which is formed in a cylindrical shape with its upstream and downstream directions narrowed, a flange 11 connected to the exhaust pipe of the engine at the upstream end, and an exhaust tape at the downstream end. A mounting plate 13 for connecting the le pipe is provided.

Reference numeral 2 denotes a filter block, which is housed in the central portion 12 of the filter case 1 and filters exhaust gas introduced from the flange 11, and has a layer of a porous ceramic 21 having conductivity and a non-conductive layer. A plurality of layers of conductive ceramic porous material 22 are alternately laminated, and the outer periphery thereof is covered with an insulating heat shield material 23 and accommodated.

The ceramic porous material 22 is made of Al2.
A heat-resistant ceramic material such as O3, mullite, or cordierite is formed into a porous urethane-like or pumice-like porous material. And the conductivity is provided by the coating of TiC.

TiC used for such vapor deposition is
For example, it is used for vapor deposition of metal surfaces with Cr and Ni, and is used for cutting tools with super hardness.
Since the coefficient of linear expansion of iC is almost the same as that of Al2 O3,
It has followability to temperature changes and has excellent reliability and durability.

Reference numerals 24 and 25 in the figure denote current-carrying plates, which are connected to the respective upper and lower end portions of the porous ceramics 21 by using a copper plate.
Since the iC is well-known, the connection is easy, and the power from the control device 3 that controls the energization can be efficiently supplied.

Next, the operation of this embodiment constructed as described above will be explained.
1 is introduced into the filter block 2 and is filtered by the porous ceramics 21 and the ceramics porous material 22 of the filter element, and the gas component is the downstream mounting plate 13
While flowing out in the direction, the particulate matter is collected and deposited on the filter element.

Next, when deposits are removed, since the porous ceramics 21 has conductivity by depositing TiC, power is supplied through the electrically connected current-carrying plates 24 and 25 and their wiring. Is supplied, the porous ceramics 21 itself generates heat to raise the temperature of the entire filter block 2.

Therefore, the deposits collected by the porous ceramics 21 and the ceramic porous body 22 are burned due to the temperature rise, incinerated and removed from these filter elements.

Although the present invention has been described with reference to the above embodiments, various modifications can be made within the scope of the gist of the present invention, and these modifications are not excluded from the scope of the present invention.

[0018]

According to the present invention as in the above embodiments,
Conductive and heat-resistant TiC was vapor-deposited on the non-conductive ceramics formed in the porous body as the material of the filter for removing particulates. However, in the present invention, the effect that the filter material can be directly energized to easily incinerate the deposit is obtained, and further, TiC has a point of a linear expansion coefficient and a weldability with Cu or the like. Since it is good, there is an advantage that a filter element having excellent reliability and long life can be obtained.

[Brief description of drawings]

FIG. 1 is a configuration block diagram showing an embodiment of a diesel particulate filter according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Filter case 2 ... Filter block 3 ... Control device 21 ... Porous ceramics 22 ... Ceramic porous body 23 ... Heat-shielding material 24, 25 ... Conductive plate

Claims (2)

[Claims] Claim: What is claimed is: 1. A diesel particulate filter for collecting particulates in exhaust gas of a diesel engine and incinerating the same by electric heat, wherein the heat resistant nonconductive material is used to form a porous body. A plurality of layers and a filter layer having conductivity by vapor-depositing TiC on the filter layer of the porous body, exhaust gas is passed in a direction perpendicular to the stack, and A diesel particulate filter characterized in that the layers of the filter are energized for incineration. 2. The material of the porous filter layer is Al.
2. At least one of 2 O 3, mullite and cordierite is used.
The described diesel particulate filter.