JPH0749021A - Diesel particulate filter - Google Patents

Abstract

PURPOSE:To efficiently collect particulates utilizing the property of the particulates gathering in a space after passing through coarse mesh by providing plural stages of sets of metal plate filter elements with coarse through hole diameter and spaces provided in slip stream. CONSTITUTION:The layers of main filter elements 1 of comb tooth shape provided with relatively coarse through holes, and spaces 11 are enclosed in a main filter case 10, and exhaust gas is made flow therein by the opening of a main passage control valve 17. Fine particulates having passed the through holes are released into the space 11 and gathered by electrification so as to grow into a large particulate, and this large particulate is collected by the element in the following stage.

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 which collects particulates contained in exhaust gas of a diesel engine.

[0002]

2. Description of the Related Art Since a diesel engine is a heterogeneous combustion in which fuel is injected into compressed air of high temperature by adiabatic compression, air and fuel are not mixed uniformly, and unburned hydrocarbons are contained in exhaust gas. A large amount of particulates due to the collection of carbon is contained and discharged.

In order to prevent the release of such particulates to the atmosphere, a particulate filter having a honeycomb structure is usually used as a filter for collecting the particulates.

[0004]

The honeycomb type filter of this type has a complicated structure and the collected particulates.
There is a problem that the exhaust resistance becomes large unless the volume of the filter is increased because the method of removing the filter is troublesome and the through hole diameter of the filter element is about 30 to 50 μm.

The present invention is intended to solve such a conventional problem, and an object thereof is to use a metal filter element having a large through-hole diameter and efficiently collect the particles by using the characteristics of fine particles of the passing particulates. An object of the present invention is to provide a diesel particulate filter which collects and has a low exhaust resistance.

[0006]

To achieve the above object, according to the present invention, exhaust gas of a diesel engine is introduced into a filter having a large number of through holes, and particulates contained in the exhaust gas are introduced. In a diesel particulate filter that collects and incinerates the filter, the filter has a plurality of sets of layers of a thin plate having a through hole and a comb-shaped concavo-convex pattern formed continuously and a downstream space. A diesel particulate filter is provided.

[0007]

Since a plurality of layers of the filter and space of the comb-like corrugated plate having a relatively coarse through hole are arranged to allow the exhaust gas to flow in, the fine particles passing through the coarse through hole of the filter are left in the space. At, the particles are aggregated due to charging and become large particles, which are collected in the through holes of the filter in the next stage, and by repeating this, even minute particles can be collected.

[0008]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of a diesel particulate filter according to the present invention.

Reference numeral 1 in FIG. 1 is a main filter element, which is a thin plate obtained by coating the outer surface of an alloy plate of nickel, chromium and iron with alumina or zirconia, and has a large number of through holes of 100 to 300 μm, and its cross section is shown in the drawing. As described above, it is processed into a wavy plate in which comb-shaped irregularities are continuously formed, and the comb-shaped inclined surface is set at an angle within 30 degrees with respect to the direction of the flow path.

A plurality of main filter elements 1 are laminated with a predetermined space 11 in the wake, and the outer periphery of the main filter element 1 is covered with a heat insulating material 12 having electrical insulation. It is stored inside.

The upstream and downstream sides of the main filter case 10 are narrowed, and the exhaust gas is introduced through the upstream pipe 13 and the downstream pipe 14, respectively.
5 and the downstream outlet 16 to be discharged, respectively.

Reference numeral 17 is a main flow path control valve, and 18 is an actuator for opening and closing the control valve, which controls the opening and closing of the exhaust flow path to the filter element 1 in response to a command from the controller 3. Reference numeral 19 is a current-carrying terminal, which is connected to both ends of the main filter element 1 connected in series and is a terminal to which power is supplied from the controller 3 when the main filter element 1 is energized and heated.

Reference numeral 2 denotes a sub-filter element, which is a corrugated plate having a comb-shaped concavo-convex pattern formed by coating an alloy plate of nickel, chromium and iron with alumina or zirconia as in the case of the main filter element 1. It is formed into a shape. In addition, a large number of holes having a diameter slightly smaller than those described above are bored through the exhaust gas, and a predetermined space 21 is provided inside the sub filter case 20.
A plurality of sub-filter elements 2 are built in at intervals.

Further, 27 is a sub-flow path control valve, 28 is an actuator thereof, which is controlled by a command of the controller 3, 29 is an energizing terminal, which is connected in series when electric power is supplied to the terminal 29. The sub filter element 2 connected thereto is configured to generate heat and incinerate the deposit.

Next, the operation of the present embodiment thus constructed will be described. The main flow path control valve 17 is opened to introduce the exhaust gas to the main filter element 1, and the particulates of large particle size in the exhaust gas are introduced. Is collected without passing through the through hole. Then, the gas component and the fine particles pass through the through holes and are opened to the space 11 provided in the downstream.

In this case, the fine particles passing through the through hole inclined at a predetermined angle collide with other fine particles at the time of the passage or at the time of releasing, and are charged with static electricity, and are released as shown in the enlarged view of FIG. The particles collide with each other in the space 11 and the particles aggregate with each other to become large particles, which flow into the downstream main filter element 1.

The through holes of the filter here are also coarse and of the same size, but the aggregated and large particles cannot be passed through the through holes and are collected, while the fine particles are passed through. , As described above, the particles are aggregated into large particles in the next space by charging.

Therefore, even if the filter has a relatively coarse through hole, the fine particles in the exhaust gas are collected by way of the plurality of sets of the filter element and the space.

When the particulates thus collected with the passage of time clog the eyes, the main flow path control valve 17 is closed and the sub flow path control valve 27 is opened by a command from the controller 3. At the same time, electric power is supplied to the energizing terminal 19 to perform a regeneration process by burning the deposit.

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

[0021]

According to the present invention as in the above embodiments,
Exhaust gas is made to flow through a filter that has a plurality of relatively coarse filter plates and layers of an alloy plate covered with alumina, so that large particles in the exhaust gas are collected and fine particles pass through the coarse particles. The particles are released to the space downstream, but at that time, the charged fine particles aggregate into large particles and are collected by the filter in the next stage.By repeating this, even the coarse filter efficiently collects the fine particles in the exhaust gas. The effect of being able to be collected is obtained, and since the through holes are made coarse, there is an advantage that the particulate filter has low exhaust resistance. Further, in the present invention, since the gas flow passing through the comb-shaped inclination within 30 ° with respect to the gas flow direction is mixed, the fine particles collide with each other and are aggregated efficiently, and the trapping after the growth into the large particles is performed. Collective effect is improved.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention and a partially enlarged view thereof.

[Explanation of symbols]

 1 ... Main filter element 2 ... Sub filter element 11 ... Space 12 ... Heat-shielding material 17 ... Main flow path control valve 21 ... Space

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location B01D 39/20 ZAB A

Claims (4)

[Claims] 1. A diesel particulate filter in which exhaust gas of a diesel engine is caused to flow into a filter having a large number of through holes to collect and incinerate particulates contained in the exhaust gas. A diesel particulate filter comprising a stack of a plurality of layers of a thin plate having coarse through holes and continuously formed with comb-like irregularities and a downstream space. 2. The thin plate is characterized in that the outer surface of an alloy plate of nickel, chromium, and iron is coated with either alumina or zirconia, and a large number of through holes of 100 μm to 300 μm are perforated. The described diesel particulate filter. 3. A diesel particulate filter according to claim 1, wherein said comb-shaped inclined surface of said thin plate has an angle within 30 degrees with respect to the flow path direction. 4. A main filter having a large capacity and a sub filter having a small capacity are connected in parallel with each other to collect the particulates by switching the flow paths, and the through holes of the sub filter are provided. 2. The diesel particulate filter according to claim 1, wherein the diameter is smaller than the through hole diameter of the main filter.