JP3130412B2 - Diesel Particulate Filter - Google Patents

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 Diesel engine combustion is a heterogeneous combustion in which fuel is injected into high-temperature air by adiabatic compression, and the mixture of air and fuel is not uniform. , And a large amount of particulates composed of carbon.

[0003] In order to prevent such particulates from being released into the atmosphere, a particulate filter having a honeycomb structure has been developed as a filter for collecting the particulates.

[0004]

The structure of such a honeycomb type filter is complicated, and it takes time to incinerate the collected and accumulated particulates.

The through-hole diameter of this type of filter is 30 to
With this through hole diameter, it is possible to remove 90% or more of smoke and particulates in the exhaust gas. However, if the passage area of the exhaust gas is not widened, the exhaust resistance becomes large. Is needed.

When the diameter of the through hole of the filter is increased, the exhaust resistance is reduced, but there is a problem that the collection efficiency is reduced.

[0007] The present invention has been made in view of such a conventional problem, and an object thereof is to increase the through-hole diameter of a filter.
It is an object of the present invention to provide a diesel particulate filter having a high collection efficiency by utilizing the property of gathering fine particles that have passed.

[0008]

According to the first aspect of the present invention, the exhaust gas of a diesel engine is caused to flow into a porous filter having a large number of through holes. A diesel particulate filter that collects and incinerates particulates contained in exhaust gas, is a porous ceramic sintered body that is connected to one of two branches upstream of the exhaust gas and has an infinite number of through holes of about 300 μm. Filter element consisting of a plurality of filter plates consisting of a plurality of filter plates spaced apart from each other with a space therebetween, and a porous ceramic connected to the other of two branches upstream of exhaust gas and having an infinite number of through holes of about 300 μm A plurality of sub-filter plates made of a sintered body are laminated at intervals with a space therebetween, and a sub-filter element smaller than the filter element and the main filter element Control valve means provided respectively upstream of the filter element and the sub-filter element to control the inflow of exhaust gas flowing into these filter elements, and provided on the filter plate of the main filter element and the sub-filter plate of the sub-filter element; And a heater coil means for incinerating the deposits deposited on the diesel particulate filter.

[0009]

The exhaust gas flows by providing a plurality of relatively coarse filter plate and space layers, so that fine particles passing through the coarse surface of the filter plate collect in the space by charging to become large particles. The particulates are collected efficiently by this repetition.

[0010]

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

In FIG. 1, reference numeral 1 denotes a filter element which is made of a heat-resistant porous ceramic sintered body and has a thickness of 300 μm.
The filter plate 11 having innumerable through holes of about m
Each filter plate 11 has a heater coil 13 embedded therein or is in contact with the heater coil, is connected in series with each other, and has terminals 14, 1
4 are attached.

Reference numeral 15 denotes a heat insulating material having heat resistance, which covers the outer periphery of the filter element 1 and shields the heat from the main filter case 10. The upstream and downstream directions of the main filter case 10 are constricted. Then, they are connected to an upstream port 31 and a downstream port 32 via an upstream pipe 16 and a downstream pipe 17, respectively.

Reference numeral 2 denotes a sub-filter element, which is formed of a porous ceramic sintered body having the same through-hole as the above-mentioned filter element, and is formed by laminating a plurality of sub-filter plates 21 with a space 22 therebetween. I have. Each heater coil 23 connected in series is buried or in contact with the sub-filter plate 21, and the sub-filter element 2 covered with the heat insulating material 25 is housed in the sub-filter case 20 and Are drawn out to the outside. Note that the sub-filter element 2 is used during the filter regeneration processing of the filter element 1, and in order to reduce the size of the entire filter system, the size of the filter element 1 is, for example, about 3 to 5 times smaller. Is formed.

Reference numeral 18 denotes a control valve for the flow path, which opens and closes the flow path to the filter element 1;
The control valve 18 and the control valve 28 are opened and closed by an actuator 19 and an actuator 29, respectively, and a command for such an operation is transmitted to a controller. It is configured to be emitted from the laser 4.

Next, the operation of this embodiment constructed as described above will be described. The control valve 18 is opened, exhaust gas flows into the filter element 1, the filter plate 11 has a through hole of 300 μm and is relatively small. Due to the coarseness, particles with large particulates are collected on the first filter plate 11, but gas components and fine particles pass through without being collected, and the space
Will be released.

In this case, the passing fine particles are charged with static electricity when they pass through a coarse filter or collide with another, and in the space 12, mutually charged fine particles are aggregated into large particles and flow into the next filter plate 11. Go.

The through-holes here have the same coarseness as described above, but the fine particles gathered and collected by charging are collected, and the remaining fine particles pass through and are released to the next space 12. Are formed into large particles by the above-described aggregation due to charging.

By repeating such a process, the exhaust gas passes through the layers of the filter plate 11 and the space 12 in a plurality of stages, so that fine particles are collected by a relatively coarse filter. Will be.

When the deposits increase with the passage of time and the filter element 1 is clogged, the control valve 18 is closed, the control valve 28 is opened, and the terminal 14 is opened in response to a command from the controller 4. , 14 and the heater coil 13
Is heated, and the deposits are incinerated by the temperature rise of the filter element 1.

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

[0021]

As described in detail above, the present invention provides
Connected to one of the two branches upstream of the exhaust gas,
A filter element in which a plurality of filter plates made of a porous ceramic sintered body having innumerable through-holes of about 0 μm are stacked at intervals through a space and a filter element which is branched in two directions upstream of exhaust gas. Connected, a plurality of sub-filter plates made of a porous ceramic sintered body having innumerable through-holes of about 300 μm are laminated at intervals via a space, and a sub-filter element smaller than the filter element; Provided upstream of the main filter element and the sub filter element, respectively.
Control valve means for controlling the inflow of exhaust gas flowing into these filter elements; heater coil means provided on the filter plate of the main filter element and the sub-filter plate of the sub-filter element to incinerate deposits deposited thereon; Therefore, large particles of the particulate matter are collected and the fine particles pass through the coarse grain.However, since the charged fine particles gather in the downstream space to become large particles, they are captured by the next-stage filter plate. By repeating this process, the effect of the present invention is obtained in which fine particles can be efficiently collected by a plurality of coarse filter plates and spaces. Moreover, the present invention has a structure in which the filter element and the sub-filter element are inserted in the exhaust gas passage in parallel, and the sub-filter element is used during the filter regeneration processing of the filter element.
During the regenerating process, the particulates can be collected by the sub-filter, and the effect of the invention unique to the present invention that the particulates can be constantly collected can be obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of the present invention.

[Explanation of symbols]

 1, 2 ... Filter element 4 ... Controller 11, 21 ... Filter plate 12, 22 ... Space 13 ... Heater coil 18, 28 ... Control valve

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F01N 3/02-3/038

Claims (1)

(57) [Claims] An exhaust gas of a diesel engine flows into a porous filter having a large number of through holes, and a particulate filter contained in the exhaust gas is collected and incinerated. 30 connected to one branch
A filter element in which a plurality of filter plates made of a porous ceramic sintered body having innumerable through-holes of about 0 μm are stacked at intervals through a space, and a filter element which is branched in two directions upstream of exhaust gas. Connected, 30
A plurality of sub-filter plates made of a porous ceramic sintered body having innumerable through-holes of about 0 μm laminated at intervals with a space therebetween; a sub-filter element smaller than the filter element; and the main filter element And control valve means provided upstream of the sub-filter element to control the inflow of exhaust gas flowing into these filter elements, and provided on the filter plate of the main filter element and the sub-filter plate of the sub filter element. A diesel particulate filter, comprising: heater coil means for incinerating a deposit to be deposited.