WO2019128560A1

WO2019128560A1 - Honeycomb ceramic filter having high thermal shock resistance

Info

Publication number: WO2019128560A1
Application number: PCT/CN2018/116703
Authority: WO
Inventors: 宋锡滨; 张兵; 张曦
Original assignee: 山东国瓷功能材料股份有限公司
Priority date: 2017-12-27
Filing date: 2018-11-21
Publication date: 2019-07-04
Also published as: CN109630236A; CN108286466A

Abstract

A honeycomb ceramic filter having high thermal shock resistance, comprising: an inlet honeycomb ceramic surface and an outlet honeycomb ceramic surface, wherein an inlet channel (1) is arranged at the inlet honeycomb ceramic surface, and an outlet channel (2) is arranged at the outlet honeycomb ceramic surface; the inlet channel (1) is in communication with the outlet channel (2); an outlet end of the inlet channel (1) and an inlet end of the outlet channel (2) are blocked; and a cross section of the outlet channel (2) is square and is provided with an outlet chamfer (5) or an outlet fillet (4).

Description

Honeycomb ceramic filter with high thermal shock resistance

Technical field

The present invention relates to the field of honeycomb ceramic filters, and more particularly to a ceramic ceramic filter having high thermal shock resistance.

Background technique

Honeycomb ceramic wall flow filters remove carbon black from gasoline and diesel exhaust. At present, the conventional filter design has an imported honeycomb ceramic surface and an outlet honeycomb ceramic surface as an inlet and an outlet, and a porous wall separating the inlet and outlet. These interconnected walls divide the filter into an inlet channel (abbreviation: I) and an outlet channel (abbreviation: O). To capture carbon black and ash, the outlet end of the inlet channel is blocked and the inlet of the outlet channel is blocked. The structure in which such an interval is blocked is like a chess board. This design forces the exhaust gas to pass through the porous wall, allowing the particulate matter to deposit in the channel or wall. Typically, the inlet and outlet channels have a square cross section of the same area. When the amount of carbon black reaches a certain level, the regeneration process takes place and the carbon black is burned off.

In practical applications, the thermal stress generated during the regeneration process causes great problems to the filter. When the thermal stress is large, it causes the filter to crack, which does not meet the environmental requirements. One solution is to regenerate when the carbon load is low, but this will result in an increase in fuel consumption of the vehicle. Therefore, the method of reducing thermal stress is preferably through improvements in filter materials and design.

At present, in the selected area (between 20 and 70 degrees), the angles of the inlet channel and the outlet channel perpendicularly or nearly perpendicular to the skin are made into an exit chamfer, thereby enhancing the thermal shock resistance. Although the thermal stress in this area can be reduced, the thermal stress in other areas is not reduced. In addition, in the area selected here, not all of the diagonals are under high thermal stress. Therefore, some export chamfers are over-designed and cause an increase in filter back pressure.

Therefore, it is necessary to clarify the area of high thermal stress, and how to improve the structure of the honeycomb ceramic filter and increase its thermal shock resistance become a problem to be solved without affecting other performances.

Summary of the invention

(1) Technical problems to be solved

The object of the present invention is to provide a honeycomb ceramic filter with high thermal shock resistance, which solves the problems of low thermal shock resistance and high back pressure of the honeycomb ceramic filter in the prior art.

(2) Technical plan

In order to solve the above technical problem, the present invention provides a honeycomb ceramic filter having high thermal shock resistance, comprising: an inlet honeycomb ceramic surface and an outlet honeycomb ceramic surface, the inlet honeycomb ceramic surface and the outlet honeycomb ceramic The surface is provided with an inlet passage and an outlet passage, the inlet passage is in communication with the outlet passage, the outlet end of the inlet passage and the inlet end of the outlet passage are blocked, and the outlet passage has a square cross section With an exit chamfer or an exit fillet.

Wherein, when the cross section of the outlet passage is square and the outlet rounding is provided, the radius of the outlet rounding is greater than 0.2 times the wall thickness between the inlet passage and the outlet passage, and is less than 0.35 Mm.

Wherein, when the cross section of the outlet passage is square and the outlet chamfer is provided, the length of the oblique side of the outlet chamfer ranges from 5% to 30% of the side length of the outlet passage.

Wherein, the inlet passage has a square cross section.

Wherein, the inlet passage is further provided with an inlet rounded corner.

Wherein, the radius of the inlet rounded corner is less than 0.125 mm.

Wherein the radius of the inlet fillet is smaller than the radius of the exit fillet.

(3) Beneficial effects

The honeycomb ceramic filter with high thermal shock resistance provided by the invention can reduce the thermal stress generated during the regeneration process by changing the structural design of the exit passage angle, and the honeycomb ceramic filter can be improved without affecting other performances. It can have better thermal shock resistance.

DRAWINGS

1 is a structural view of an inlet honeycomb ceramic surface according to Embodiment 1 of the present invention;

Figure 2 is a detailed view of the inlet honeycomb ceramic surface I of Figure 1;

Figure 3 is a detailed view of the outlet passage II of Figure 2;

4 is a structural view of an inlet honeycomb ceramic surface according to Embodiment 2 of the present invention;

Figure 5 is a detailed view of the inlet honeycomb ceramic surface I of Figure 4;

Figure 6 is a detailed view of the outlet passage II of Figure 5;

Figure 7 is a structural view of an inlet honeycomb ceramic surface according to Embodiment 3 of the present invention;

Figure 8 is a detailed view of the inlet honeycomb ceramic surface I of Figure 7;

Figure 9 is a detailed view of the outlet passage II of Figure 8;

Figure 10 is a structural view of an inlet honeycomb ceramic surface according to Embodiment 4 of the present invention;

Figure 11 is a detailed view of the inlet honeycomb ceramic surface I of Figure 10;

Figure 12 is a detailed view of the outlet passage II of Figure 11.

In the figure, 1, the inlet channel; 2, the outlet channel; 3, the inlet rounded corner; 4, the exit round corner; 5, the outlet chamfer.

Detailed ways

The specific embodiments of the present invention are further described in detail below with reference to the drawings and embodiments. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.

In the description of the present invention, it should be noted that the terms "installation", "connected", and "connected" are to be understood broadly, and may be fixed or detachable, for example, unless otherwise explicitly defined and defined. Connected, or integrally connected; can be mechanical or electrical; can be directly connected, or indirectly connected through an intermediate medium, can be the internal communication of the two components. The specific meaning of the above terms in the present invention can be understood in a specific case by those skilled in the art.

As shown in FIG. 1 to FIG. 12, an inlet honeycomb ceramic surface and an outlet honeycomb ceramic surface, the inlet honeycomb ceramic surface and the outlet honeycomb ceramic surface are respectively provided with an inlet passage and an outlet passage, the inlet passage and the inlet passage The outlet passage is in communication, the outlet end of the inlet passage and the inlet end of the outlet passage are closed, the outlet passage has a square cross section and is provided with an outlet chamfer or an outlet rounded corner.

Specifically, the filter has a skin (i.e., an outer side wall) and the filter may be circular, elliptical, or other shape. The filter consists of a series of inlet and outlet channels formed by interconnected porous walls. The inlet and outlet channels extend all the way to the ends of the filter. This filter is formed by an extrusion process. Generally, the material of this filter is ceramic materials such as cordierite, silicon carbide, aluminum titanate, and mullite, but other extrudable materials such as glass, glass ceramics, plastics, and metals. .

The honeycomb ceramic filter has an inlet passage for the exhaust gas to enter, and an outlet passage for the tail gas to flow out. For the inlet channel, the outlet end is blocked and the inlet end is not blocked; for the outlet channel, the inlet end is blocked and the outlet end is not blocked. The inlet and outlet channels are separated by walls. Generally, the filter has a porosity of between 20% and 70%. For gasoline engines and diesel exhaust filters, the average pore size is between 5 and 50 microns, preferably between 10 and 30 microns. Honeycomb ceramic filters have from 50 to 350 squares per square inch, preferably from 100 to 300 squares. The wall thickness can range from 0.05 to 0.5 mm, preferably from 0.1 to 0.4 mm.

In order to increase the thermal shock resistance of the outlet passage, the angle of the outlet passage is designed. Regarding the inlet passages, thermodynamic strengthening is not necessary because they are under compressive stress during sudden changes in temperature during regeneration. To maintain a low back pressure, it is best to keep the square shape or only a small rounded corner.

Example 1:

As shown in Figures 1-3, the inlet passage has a square cross section and no rounded corners. The outlet passage has a square cross section and is provided with an outlet fillet, and the radius of the outlet fillet is greater than 0.2 times the wall thickness between the inlet passage and the outlet passage, and is less than 0.35 mm.

Example 2:

As shown in Figures 4-6, the inlet passage has a square cross section with no rounded corners. The outlet passage has a square cross section and is provided with an outlet chamfer having a bevel length ranging from 5% to 30% of the side length of the outlet passage.

Example 3:

As shown in Figures 7-9, the inlet passage has a square cross section and is provided with inlet fillets. The outlet passage has a square cross section and is provided with an outlet fillet, and the radius of the outlet fillet is greater than 0.2 times the wall thickness between the inlet passage and the outlet passage and is less than 0.35 mm.

Example 4:

As shown in Figures 10-12, the inlet passage has a square cross section and is provided with inlet fillets. The outlet passage has a square cross section and is provided with an outlet chamfer having a bevel length ranging from 5% to 30% of the side length of the outlet passage.

Example 5:

The present embodiment is substantially the same as the embodiment 3. For the sake of brevity of description, the same technical features as those of the embodiment 3 will not be described in the description of the embodiment, and only the difference between the embodiment and the embodiment 3 will be described. The radius of the imported rounded corner is less than 0.125mm.

Example 6

This embodiment is basically the same as the embodiment 4. For the sake of brevity of description, the same technical features as those of the embodiment 4 will not be described in the description of the embodiment, and only the difference between the embodiment and the embodiment 4 will be described. The radius of the imported rounded corner is less than 0.125mm.

Example 7

This embodiment is basically the same as the embodiment 5. For the sake of brevity of description, the same technical features as those of the embodiment 5 will not be described in the description of the embodiment, and only the difference between the embodiment and the embodiment 5 will be described. The radius of the inlet fillet is smaller than the radius of the exit fillet.

Example 8

The present embodiment is substantially the same as the embodiment 6. For the sake of brevity of description, the same technical features as those of the embodiment 6 will not be described in the description of the embodiment, and only the difference between the embodiment and the embodiment 6 will be described. The radius of the inlet fillet is smaller than the radius of the exit fillet.

Specifically, the rounded corners of the above embodiments are formed by electric discharge machining or by grinding with an abrasive tool.

According to the above embodiment, an experiment was conducted to detect the maximum thermal stress of the filter, and the inlet and outlet passages were all square, and no rounding and chamfering were used as a comparison example of the prior art; the outlet passage was provided with rounded corners and a circle The angular radius of 0.25 mm is the first embodiment of the present invention; the outlet passage is chamfered, and the chamfered bevel length is 0.25 mm, which is the second embodiment of the present invention. The following is an experimental comparison:

It can be seen from the above explanation and calculation that the thermal stress generated during the regeneration process can be reduced by changing the design of the exit passage angle. Therefore, the honeycomb ceramic filter can have superior thermal shock resistance without affecting other properties.

The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., which are included in the spirit and scope of the present invention, should be included in the present invention. Within the scope of protection.

Claims

A honeycomb ceramic filter with high thermal shock resistance, comprising: an inlet honeycomb ceramic surface and an outlet honeycomb ceramic surface, wherein the inlet honeycomb ceramic surface and the outlet honeycomb ceramic surface are provided with an inlet passage and An outlet passage, the inlet passage is in communication with the outlet passage, an outlet end of the inlet passage and an inlet end of the outlet passage are blocked, the outlet passage has a square cross section, and is provided with an outlet chamfer or an outlet Rounded corners.
The honeycomb ceramic filter having high thermal shock resistance according to claim 1, wherein when the cross section of the outlet passage is square and the outlet rounding is provided, the radius of the outlet rounding is larger than The wall thickness between the inlet passage and the outlet passage is 0.2 times and less than 0.35 mm.
A ceramic ceramic filter having high thermal shock resistance according to claim 1, wherein when the cross section of the outlet passage is square and the outlet chamfer is provided, the length of the oblique side of the outlet chamfer The range is 5% to 30% of the side length of the outlet passage.
A ceramic ceramic filter having high thermal shock resistance according to claim 2 or 3, wherein the inlet passage has a square cross section.
A ceramic ceramic filter having high thermal shock resistance according to claim 4, wherein said inlet passage is further provided with an inlet rounded corner.
A ceramic ceramic filter having high thermal shock resistance according to claim 5, wherein said inlet rounded corner has a radius of less than 0.125 mm.
A honeycomb ceramic filter having high thermal shock resistance according to claim 6, wherein the radius of the inlet rounded corner is smaller than the radius of the outlet rounded corner.