KR100727182B1 - Channel volume variable type diesel catalyzed particulate filter - Google Patents

Abstract

A channel volume variable type diesel catalyzed particulate filter which improves a problem of increase in an initial ambient pressure by securing channel volume of outlet channels that is the same level as that of inlet channels, and can collect much ash as compared with an ordinary filter by increasing area of the inlet channels than that of the outlet channels is provided. A channel volume variable type diesel catalyzed particulate filter(30) for improving initial ambient pressure comprises: inlet channels(31) formed in such a shape that an entrance of the inlet channels is relatively expanded by inclining a wall(33); outlet channels(32) formed in such a shape that an exit of the outlet channels is relatively contracted by inclining the wall, wherein cross sectional area of the inlet channels is gradually decreased as it goes from a front side to a rear side of the inlet channels while sectional area of the outlet channels is gradually increased as it goes from a front side to a rear side of the outlet channels. The filter further comprises heat-expandable members(34) which are installed in closed portions formed at rear ends of the inlet channels, and of which a vertical length is increased when the heat-expandable members are heated. The heat-expandable members include an outer member(35) constructed in a creased structure, and a heat-expandable filler(36) filled in the outer member.

Description

Channel volume variable type diesel catalyzed particulate filter for improving initial back pressure

1 is a view showing a channel structure of a conventional diesel particulate catalyst filter;

2a and 2b is a view showing a comparison between the filter of the general symmetric channel structure and the ACT filter of the asymmetric channel structure,

3 and 4 are cross-sectional views showing the structure of the diesel particulate catalyst filtration filter (CPF) according to the present invention.

<Explanation of symbols for the main parts of the drawings>

30 Diesel soot catalyst filtration filter 31 Inlet channel

32: outlet channel 33: the wall

34: thermally expandable member 35: outer member

36: thermally expandable filler

The present invention relates to a channel volume variable diesel soot catalyst filtration filter for improving the initial back pressure, and more particularly, the volume of the outlet channel and the outlet channel is approximately equal to that of the outlet channel such as a general filter. The problem of the initial back pressure increase of the filter can be solved, and after the filter regeneration, the inlet channel is wider than the outlet channel due to the expansion of the thermally expandable member, and thus the channel volume is variable to collect more ash than the general filter. A diesel soot catalyst filtration filter.

In general, automobile exhaust gas refers to a gas produced by the combustion of a mixer in an engine and released into the atmosphere through an exhaust pipe.

The exhaust gas contains a large amount of harmful substances such as carbon monoxide (CO), nitrogen oxides (NOx), unburned hydrocarbons (HC).

Therefore, preventing air pollution due to automobile exhaust gas has emerged as an important issue for environmental hygiene, and automobiles are regulated to be cleaned before exhaust gas is discharged.

The most commonly used device for purifying exhaust gas in automobiles is a catalytic converter using a three way catalyst, which is installed in the middle of an exhaust pipe, and the specification of the catalyst is different because the exhaust gas emission varies depending on the vehicle.

The three-way catalyst refers to a catalyst that removes these compounds by reacting simultaneously with the harmful components of the exhaust gas such as carbon monoxide, nitrogen oxides and hydrocarbon-based compounds, and is mainly a three-way catalyst of Pt / Rh, Pd / Rh or Pt / Pd / Rh system. Is used.

On the other hand, in the case of diesel vehicles, which have relatively high emissions of harmful exhaust gases, in spite of their excellent fuel efficiency and output, they contain a large amount of nitrogen oxides and particulate matter (PM), unlike gasoline vehicles. .

As such, in a diesel vehicle, carbon monoxide and hydrocarbons are emitted much less than gasoline vehicles because air is sufficiently burned in most operating conditions, but nitrogen oxides and particulate matter are emitted.

Recently, particulate matter has been identified as the main cause of air pollution, and has been found to cause many harms to the human body.

Therefore, the exhaust gas reduction technology of diesel vehicles has been focused on the reduction of particulate matter including nitrogen oxides and soot.

Recently, research on diesel particulate filter as an aftertreatment technology has been actively conducted to cope with the emission standard of diesel vehicles. In order to apply the diesel particulate filter to actual vehicles, much research is still required.

A structure (DOC + DPF) that uses platinum (Pt) for diesel oxidation catalyst (DOC) and a diesel particulate filter (DPF) is developed and mass-produced recently by European car manufacturers. By doing so, there is a lot of reliability improvement and sales.

In addition, a diesel particulate filter having a catalyst-coated structure, that is, a diesel particulate catalyst filter (hereinafter referred to as CPF) has been developed.

On the other hand, CPF has a different structure from the conventional cordierite carrier.

That is, as shown in Figure 1, in order to filter the soot (soot), one side of each channel has an open structure and the other side is blocked, so that the soot is filtered through the wall and passing only the gas component have.

When the smoke is collected in the filter and a certain amount of smoke accumulates over time, the smoke accumulates as the regeneration is performed at a high temperature of about 650 ° C. At this time, the smoke is burnt in the channel and ash is removed. Will accumulate.

In such a CPF, if a large amount of ash is accumulated in the filter, the overall volume of the CPF can be reduced, thereby moving closer to the engine room, and also advantageous in various aspects such as layout.

In practice, the ACT filter and some filters have applied techniques to increase the volume (channel volume) of the inlet channel into which exhaust gas flows, and to relatively reduce the volume of the outlet channel through which the filtered exhaust gas flows out.

2A and 2B are views illustrating a comparison of a filter having a general symmetric channel structure and an symmetric cell technology (ACT) filter having an asymmetric channel structure.

As shown in the drawing, both the filter 10 and the ACT filter 20 of the general symmetrical channel structure have a structure in which one side of each channel 11, 12, 21, 22 is open and the other side is blocked. It has a structure that is filtered through the wall and passes only gas components.

In addition, in the general filter 10, the inlet channel 11 and the outlet channel 12 have substantially the same volume, and in the ACT filter 20, the volume of the outlet channel 22 through which the exhaust gas is exhausted is the inlet channel ( It is designed relatively small compared to the volume of 12).

However, when the volume of the outlet channel 22 is designed to be smaller than the volume of the inlet channel 21, such as the ACT filter 20, it is possible to collect a lot of ash after playback in the inlet channel 21 compared to the general filter 10. It can be advantaged, but there is a problem that takes a lot of initial back pressure.

Accordingly, the present invention is invented to solve the above problems, and increases the initial back pressure of the conventional ACT filter by securing the volume of the outlet channel at the same level as the volume (channel volume) of the inlet channel like a general filter. After the filter regeneration, the inlet channel is wider than the outlet channel due to the expansion of the thermally expandable member, thereby providing a channel volume variable diesel particulate catalyst filter that can collect more ash than the general filter. The purpose is.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

The present invention provides a diesel particulate catalyst filtration filter (CPF) having a structure in which one side of each channel is open and the other side is blocked.

The wall partitioning each channel has an inclined structure, and the inlet channel into which the exhaust gas flows into the rear end is gradually reduced in cross section, and the outlet channel through which the filtered exhaust gas is discharged to the rear end. The cross-sectional area of the inlet channel is gradually widened, and the inlet channel is widened than the outlet channel after regeneration by installing a thermally expandable member that is expanded in length by heat at the rear end of the inlet channel.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

3 and 4 are cross-sectional views illustrating the structure of the diesel particulate catalyst filtering filter (CPF) according to the present invention, in which only a part of the entire filter is enlarged and schematically illustrated, and FIG. 3 shows a state before regeneration occurs. 4 shows the state after regeneration has taken place.

Here, reference numeral 31 denotes an inlet channel through which exhaust gas including soot flows, and reference numeral 32 denotes an outlet channel through which filtered exhaust gas flows and is discharged.

In the present invention, the filter 30 is made of a metal material that can be deformed as shown in FIG. 3.

That is, in the channel structure of the filter 30, the wall 33 is inclined so that the entrance of the inlet channel 31 is enlarged relatively large and the outlet of the outlet channel 32 is relatively reduced. It is.

Therefore, the inlet channel 31 has a structure in which the cross-sectional area gradually decreases while going to the rear end, and the outlet channel 32 has a structure in which the cross-sectional area gradually widens while going to the rear end.

In this case, since the volume of the inlet channel 31 and the outlet channel 32 is about the same, there is no big difference from the conventional general CPF. In particular, since the volume of the outlet channel 32 is not small, it is not disadvantageous in terms of back pressure. The problem that the initial back pressure was large in the ACT filter can be solved.

In the present invention, the thermally expandable member 34 is provided to increase the vertical length when the inlet channel 31 receives heat from the blocked portion of the rear end.

The thermally expandable member 34 is configured by filling a thermally expandable filler 36 whose volume increases when heat is received inside the outer member 35 having a corrugated structure to enable vertical stretching.

Hereinafter, the state at the time of soot filtration and regeneration in the CPF according to the present invention.

When exhaust gas including soot enters the channel through the inlet of the inlet channel 31, the soot is caught by the wall 33 and passes through the gaseous component to the outlet channel 32. Gas is to be discharged through the outlet of the outlet channel (32).

And, when the soot is collected in the filter 30 and a certain amount of soot is accumulated over time, the soot is burned as the regeneration is performed at a high temperature of about 650 ° C. At this time, the soot is in the inlet channel 31. It burns and ash builds up.

In addition, during regeneration, as the thermally expandable member 34 expands due to a rapid temperature increase, the length of the rear end portion of the inlet channel 31 increases as shown in FIG. 4, and after the regeneration occurs, the filter 30 ), The inlet channel 31 becomes wider than the outlet channel 32 like the ACT filter, so that more ash can be collected than the general filter.

In this way, in the CPF according to the present invention, the volume of the inlet channel and the outlet channel is about the same, and the problem of the initial back pressure increase of the conventional ACT filter can be solved, and after the filter regeneration, the inlet channel is expanded due to the expansion of the thermally expandable member. It is wider than this outlet channel, so it can capture a lot of ash.

As described above, according to the variable channel volume diesel particulate filter according to the present invention, the volume of the inlet channel and the outlet channel is approximately equal, so that the volume of the outlet channel such as a general filter can be secured. The problem of the initial back pressure increase can be solved, and since the inlet channel is wider than the outlet channel due to the expansion of the thermally expandable member after the filter regeneration, there is an advantage that can collect more ash than the general filter.

Claims (1)

In a diesel particulate catalyst filtration filter (CPF) having a structure in which one side of each channel is open and the other side is blocked, The wall partitioning each channel has an inclined structure, and the inlet channel into which the exhaust gas flows into the rear end is gradually reduced in cross section, and the outlet channel through which the filtered exhaust gas is discharged to the rear end. The cross-sectional area gradually increases while the initial back pressure is characterized in that the inlet channel is wider than the outlet channel after regeneration by installing a thermally expandable member that is expanded in length by heat at the rear end of the inlet channel. Channel volume variable diesel particulate catalyst filtration filter for improvement.

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