KR20110023153A - Exhaust gas purification system - Google Patents

Abstract

PURPOSE: An exhaust gas purification system is provided to prevent the deterioration of an oxidation catalyst arranged in the rear of a main catalyzed particulate filter and improve the regeneration efficiency of the main catalyzed particulate filter by lowering the temperature of the rear side of the main catalyzed particulate filter while raising the temperature of the front side. CONSTITUTION: An exhaust gas purification system comprises an exhaust line(110) which exhaust gas passes through, a sub catalyzed particulate filter(120) which is installed in the exhaust line to collect particulates inclined in a part of exhaust gas while passing the rest, and a main catalyzed particulate filter(130) which is arranged in the rear of the sub catalyzed particulate filter to collect particulates inclined in exhaust gas and removes the particulates at the set time intervals.

Description

Exhaust Gas Purification System {EXHAUST GAS PURIFICATION SYSTEM}

The present invention relates to an exhaust gas purification system, and more particularly, to an exhaust gas purification system for purifying exhaust gas.

In general, the exhaust system of the engine functions to discharge the exhaust gas to the rear of the vehicle and to reduce the exhaust sound.

Recently, catalytic devices have been used to purify exhaust gases, which convert harmful emissions into harmless nitrogen, carbon dioxide, or water.

That is, the catalytic device reduces hydrocarbons, carbon monoxide, and nitrogen oxides (NOx), and collects or burns particulate matter.

In general, a catalytic device that physically collects and burns particulate matter discharged from diesel is called a diesel particulate filter (DPF), and the diesel particulate filter has a plurality of channels formed in an exhaust gas flow direction. .

In addition, at least one of the channels has a structure in which the inlet is closed and the outlet is open, and at least one of the channels is the inlet is opened, the outlet is closed, and the closed part of the inlet or outlet is alternately arranged. .

The inlet and the outlet of the channels are alternately plugged and have a structure in which a catalyst layer is formed on the surface of the channels. Generally, a porous filter through which exhaust gas is permeated is used in a catalytic device, which is formed of SiC or AT material.

On the other hand, when the oxidation catalyst (DOC) is disposed at the rear end of the catalyst filtration filter (DPF), there is a problem that the oxidation catalyst is deteriorated by the heat of oxidation of the filtration catalyst. Accordingly, there is a problem in that generation of nitrogen dioxide is reduced, hydrocarbons are slipped, and the function of the selective reduction catalyst is reduced due to a decrease in the function of the oxidation catalyst.

It is an object of the present invention to provide an exhaust gas purification system which prevents deterioration of an oxidation catalyst (DOC) mounted at a rear end of a catalytic filtration filter (DPF). In addition, to provide an exhaust gas purification system for improving the regeneration efficiency of the catalytic filtration filter.

According to the present invention for achieving this object, the exhaust gas purification system according to an embodiment of the present invention, the exhaust line through which the exhaust gas, trapped particulate matter contained in a part of the exhaust gas installed in the exhaust line and In addition, a precatalyst filtration filter (pre DPF) which passes another part of the exhaust gas as it is, and a main catalyst filtration filter (DPF) disposed at the rear end of the precatalyst filtration filter to collect particulate matter contained in the exhaust gas and remove it at a set cycle. ) May be included.

An oxidation catalyst (DOC) may be disposed at a rear end of the main catalyst filtration filter.

A selective reduction catalyst (SCR) may be disposed after the oxidation catalyst, and a dosing module may be disposed between the oxidation catalyst and the selective reduction catalyst.

An exhaust line through which exhaust gas passes, a precatalyst filtration filter (pre DPF) installed in the exhaust line to trap particulate matter contained in a portion of the exhaust gas and pass the other portion as it is, and a rear end of the cocatalyst filter And a main catalyst filtration filter (DPF) disposed to collect particulate matter contained in the exhaust gas and to remove the particulate matter in a set cycle. The co-catalyst filter includes a carrier having a plurality of channels formed from front to back to flow the exhaust gas. And the channels comprising: a first channel whose inlet is open and whose outlet is closed; A second channel whose inlet is closed and whose outlet is open; And a third channel in which both the inlet and the outlet are open.

Post-injection is performed in an engine to raise the temperature of the front end of the co-catalyst filter to a set temperature to remove particulate matter trapped in the co-catalyst filter, and to set the temperature of the front end of the main catalyst filtration filter to a set temperature. The control unit may further include a controller configured to increase and oxidize and remove particulate matter collected in the main catalyst filtration filter at a predetermined cycle.

An exhaust line through which the exhaust gas passes, and a catalyst filtration filter (DPF) installed in the exhaust line to collect particulate matter contained in a part of the exhaust gas, and the other part of the exhaust gas as it passes through. have.

As described above, according to the exhaust gas purifying system according to the present invention, an auxiliary catalyst filtration filter is disposed at the front end of the main catalyst filtration filter, and the temperature of the front end of the main catalyst filtration filter is increased, but the rear end of the main catalyst filtration filter is increased. The temperature is lowered to prevent deterioration of the oxidation catalyst disposed at the rear end of the main catalyst filter and to improve the regeneration efficiency of the main catalyst filter.

In addition, the deterioration of the oxidation catalyst is prevented to improve the purification efficiency of the selective reduction catalyst installed at the rear end of the oxidation catalyst, and the regeneration of the catalyst is easily controlled by using the cocatalyst filtration filter.

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

1 is a schematic diagram illustrating an exhaust gas purification system according to an exemplary embodiment of the present invention.

Exhaust gas purification system according to an embodiment of the present invention, the engine 100, the exhaust line 110, the auxiliary catalyst filtration filter 120, the main catalyst filtration filter 130, the oxidation catalyst 140, the reducing agent supply device 150, and a selective reduction catalyst 160.

The exhaust line 110 discharges the exhaust gas discharged from the engine 100 to the outside, and the auxiliary catalyst filtration filter 120, the main catalyst filtration filter 130, and the oxidation catalyst are discharged to the exhaust line 110. 140, the reducing agent supply device 150, and the selective reduction catalyst 160 are sequentially disposed.

In an embodiment of the present invention, the co-catalyst filter 120 may be referred to as pre-DPF, and the main catalyst filtration filter 130 may be referred to as DPF.

The co-catalyst filter 120 is uniformly coated with a noble metal to remove a part of the soluble organic component (SOF), and collect a part of the particulate matter.

The main catalyst filtration filter 130 is coated with a noble metal to collect the remaining part of the particulate matter contained in the exhaust gas passing through the co-catalyst filter 120, and removes all remaining SOF. In addition, it regenerates by oxidizing the entrant substance collected on the set conditions.

In the first stage, after the first injection is carried out in the engine, the temperature of the front end of the co-catalyst filter 120 rises to about 300 degrees, and in the second step, after the second injection in the engine is carried out, As the HC increases, the particulate matter collected in the cocatalyst filter 120 is oxidized, and the temperature at the rear end thereof is increased to 580-620 degrees.

The regeneration of the main catalyst filtration filter 130 is carried out under the condition that the temperature of the rear end of the main catalyst filtration filter 130 is 700 to 800 degrees or less, and the regeneration to remove the collected particulate matter is the co-catalyst filtration filter. Regeneration (oxidation) heat of 120 and HC oxidation heat of the main catalyst filtration filter 130.

The regeneration period of the main catalyst filtration filter 130 may be set to a set amount (1000 km) or the traveling distance exceeds the set amount (4 g / L) of the collected particulate matter.

On the other hand, it is essential to maintain the set temperature in order to regenerate the main catalyst filter 130, in the embodiment of the present invention because the co-catalyst filter 120 to increase the temperature of the rear end through the oxidation reaction The regeneration efficiency of the main catalyst filtration filter 130 is improved.

In addition, since a part of the fuel is pre-oxidized in the co-catalyst filter 120 and the main catalyst filtration filter 130 is regenerated using the remaining fuel, substantially the rear end of the main catalyst filtration filter 130. The temperature is lowered to prevent deterioration of the oxidation catalyst 140.

The oxidation catalyst 140 oxidizes and reduces harmful substances (HC, CO) and the like contained in the exhaust gas. In addition, the reducing agent supply device 150 mounted at the rear end of the oxidation catalyst 140 injects fuel for urea or reducing agent into the exhaust line 110. The reducing agent supply device 150 may be referred to as a Dosing module.

The selective reduction catalyst 160 reduces and removes harmful substances (NOx) contained in exhaust gas by using the reducing agent.

By applying the co-catalyst filtration filter 120, the regeneration heat of the main catalyst filtration filter 130 during the regeneration is prevented from rising to a temperature higher than the set value of the rear end to prevent degradation of the oxidation catalyst 140 do. In addition, it enhances the performance of Fe-zeolite.

2 is a schematic cross-sectional view of the co-catalyst filtration filter provided in the exhaust gas purification system according to an embodiment of the present invention.

Referring to FIG. 2, the cocatalyst filtration filter 120 includes a carrier 200 in which a plurality of channels 210 are formed in a flow direction of exhaust gas.

The carrier 200 includes a first channel 210a, a second channel 210b, and a third channel 210c through which exhaust gas flows from the front part to the opposite rear part.

The first channel 210a has an inlet opening and an outlet is closed, and the second channel 210b has both an inlet and an outlet opening, and the third channel 210c has an inlet opening and an outlet opening. Has

Inlet of the third channel 210c is closed by the first plug 220a, and outlet of the first channel 210a is closed by the second plug 220b.

As shown, the entry material contained in the exhaust gas is collected at the rear end of the first channel 210a, and the exhaust gas entering through the inlet of the second channel 210b is directly through the outlet. It moves to the catalyst filtration filter 130.

As described above, the sub-catalyst filter 120 has a structure in which a part of the exhaust gas is filtered and the other part passes as it is, thereby lowering the flow resistance of the exhaust gas, and reducing the load of the main catalyst filter 130. give.

In addition, by improving the regeneration efficiency of the main catalyst filtration filter 130 by oxidizing a part of the exhaust gas to increase the temperature of the rear end, and after the combustion of a part of the fuel contained in the exhaust gas in advance of the main catalyst filtration filter 130 The negative temperature is prevented from rising higher than the set temperature.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and can be easily changed by those skilled in the art from the embodiments of the present invention. Includes all changes that are considered to be equivalent.

1 is a schematic diagram illustrating an exhaust gas purification system according to an exemplary embodiment of the present invention.

2 is a schematic cross-sectional view of the co-catalyst filtration filter provided in the exhaust gas purification system according to an embodiment of the present invention.

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

100: engine

110: exhaust line

120: cocatalyst filtration filter

130: main catalyst filtration filter

140: oxidation catalyst

150: reducing agent supply device

160: selective reduction catalyst

200: carrier

210: channel

210a: first channel

210b: second channel

210c: third channel

220a: first plug

220b: second plug

Claims (8)

An exhaust line through which the exhaust gas passes; A precatalyst filtration filter (pre DPF) installed in the exhaust line to collect particulate matter contained in a part of the exhaust gas and pass the other part of the exhaust gas as it is; And A main catalyst filtration filter (DPF) disposed at a rear end of the co-catalyst filtration filter to collect particulate matter contained in the exhaust gas and to remove the particulate matter in a set cycle; Exhaust gas purification system comprising a. According to claim 1, An oxidation catalyst (DOC) is disposed at a rear end of the main catalyst filtration filter. The method of claim 2, A selective reduction catalyst (SCR) is disposed at the rear of the oxidation catalyst, and a dosing module is disposed between the oxidation catalyst and the selective reduction catalyst. An exhaust line through which the exhaust gas passes; A precatalyst filtration filter (pre DPF) installed in the exhaust line to collect particulate matter contained in a part of the exhaust gas and pass the other part as it is; And A main catalyst filtration filter (DPF) disposed at a rear end of the co-catalyst filtration filter to collect particulate matter contained in the exhaust gas and to remove the particulate matter in a set cycle; Including, The cocatalyst filtration filter includes a carrier having a plurality of channels formed from front to rear to allow exhaust gas to flow therethrough, The channels may include: a first channel whose inlet is open and whose outlet is closed; A second channel whose inlet is closed and whose outlet is open; And a third channel in which both its inlet and its outlet are open; Exhaust gas purification system comprising a. 5. The method of claim 4, An oxidation catalyst (DOC) is disposed at a rear end of the main catalyst filtration filter. 6. The method of claim 5, A selective reduction catalyst (SCR) is disposed at the rear of the oxidation catalyst, and a dosing module is disposed between the oxidation catalyst and the selective reduction catalyst. 6. The method of claim 5, After the injection is carried out in the engine, the temperature of the front end of the co-catalyst filter is raised to a set temperature to remove particulate matter collected in the co-catalyst filter, A controller configured to increase the temperature of the front end of the main catalyst filter to a predetermined temperature to oxidize and remove particulate matter collected in the main catalyst filter at a predetermined cycle; Exhaust gas purification system further comprising. An exhaust line through which the exhaust gas passes; And A catalyst filtration filter (DPF) installed in the exhaust line to collect particulate matter contained in a part of the exhaust gas and pass the other part of the exhaust gas as it is; Exhaust gas purification system comprising a.

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