KR101191883B1 - Diesel vehicles exhaust gas purification device and control method thereof - Google Patents

Abstract

The present invention relates to an exhaust gas purification apparatus for a diesel vehicle having a fuel injection device, a diesel oxidation catalyst 300 coated with an exhaust gas purification catalyst, and a diesel particle filter 400 coated with an exhaust gas purification catalyst, and a control method thereof. The exhaust gas purification device is installed in the exhaust pipe 110 connected to the engine 100, and the fuel / air injector 200 injects fuel / air into the exhaust gas; A diesel oxidation catalyst 300 installed at a rear end of the fuel / air injector 200 to increase the temperature of the exhaust gas through the fuel / air injected by the fuel / air injector 200; And a diesel particle filter 400 disposed at a rear end of the diesel oxidation catalyst 300 to remove particulate matter, wherein the fuel / air injector 200 forms a body and is connected to the exhaust pipe 100. Tubular housing 201; A fuel / air injection nozzle 210 disposed at an upstream center of the housing 201 and injecting fuel / air toward a downstream side; And a fuel / air supply unit 240 connected by the fuel / air injection nozzle 210 and the fuel / air supply line 220 to supply and block the fuel / air.

Description

Diesel vehicle exhaust gas purification device and control method

The present invention provides a diesel exhaust gas purification apparatus and a control method thereof. In particular, the present invention provides a composite regeneration device suitable for a vehicle having a low average temperature of exhaust gas and its operation method. The diesel exhaust gas purification apparatus includes a diesel oxidation catalyst (hereinafter referred to as DOC), a catalyst-coated diesel particulate filter (hereinafter referred to as cDPF) and a fuel injector. Accordingly, it is possible to provide a post-treatment apparatus having high particulate matter removal efficiency that can be applied to a vehicle in which the average temperature of the exhaust gas is low due to the long-term low-speed driving pattern and thus self-continuous regeneration is impossible.

Recently, the demand for high fuel consumption vehicles is increasing due to the tightening regulation of carbon dioxide (CO ₂ ) emissions for the entire industry. For this reason, the demand for diesel vehicles using diesel engines is increasing. In the case of such a diesel engine, when the fuel is burned in the engine compartment, the fuel is directly injected to an oxygen condition in excess of the theoretical air-fuel ratio and combusted so that the combustion efficiency of the fuel is high and fuel efficiency is excellent, whereas particulate matter (PM) is called PM. And nitrogen oxides (here, nitrogen oxides refer to both NO and NO ₂ and hereinafter referred to as NOx).

In the exhaust gas purifier 1000, unburned hydrocarbons and carbon monoxide contained in the exhaust gas discharged from the engine 100 are oxidized and harmless on the DOC 300 as shown in FIG. 1, and the particulate matter is cDPF. It is captured at 400 and oxidized. Nitrogen oxide contained in the exhaust gas discharged from the cDPF 400 is reduced to nitrogen (N ₂ ) through a reduction reaction in a selective reduction catalyst 500 together with a reducing agent supplied from the rear end of the diesel particle filter 400. Configuration is common.

In the case of finished vehicles, vehicles equipped with all the above devices and satisfying the Euro V regulations are being released. However, aftertreatment devices applicable to vehicles in operation, in particular, reducing particulate matter (PM), which is essential for satisfying the regulation of Euro IV level Many studies have been conducted because the necessity of a device for this has been raised.

As a post-treatment device of the type applicable to the driving vehicle, a cDPF for removing particulate matter applicable to a large-sized mobile bus having a high average exhaust gas temperature has been commercialized. However, the post-treatment apparatus applicable to a small and medium-sized vehicle having a low exhaust gas temperature and a vehicle having frequent short-distance low-speed driving needs to develop an exhaust gas purifying apparatus having a complex regeneration or forced regeneration device capable of generating a separate heat source.

In order to solve the above problems, a form in which a forced regeneration method of heating exhaust gas through heating means of an electric heater, a burner, and a plasma heater has been proposed has been proposed. The heating means also has a space required for mounting the heating device, the amount of power available and fuel consumption problems are also applicable vehicle models are limited.

Therefore, as an essential matter for the complex regeneration device having the heat source generator, satisfaction of the mountability and economy is required. First, compactness of the heating device is required to satisfy the mountable part, and second, power and fuel consumption rate for heat generation is minimized.

The researchers also conducted research for the development of a heat source generator, and Korea Patent Registration No. 10-0754494 (Internal combustion engine exhaust gas heating device), Korea Patent Registration No. 10-0679716 (Air intake type internal combustion engine exhaust gas heating Device), Korean Patent Registration No. 10-0725265 (Exhaust gas heating device for internal combustion engine with oxidant control device), Korean Patent Registration No. 10-0782134 (Fuel and air supply device for hydrocarbon reforming / combustion device), Korean patent application No. 10-2008-0045571 (Heating device for an exhaust gas purification device, a control method thereof, and an exhaust gas purification device including the heating device) has been filed. However, such a device worsens fuel efficiency due to increased fuel consumption, such as mounting, and has a problem in economics when the production amount is below a certain amount due to the large number of components of the heating device.

Therefore, in order to solve the fundamental problem of the above problem, the researchers have studied in terms of improving the activity of the PM oxidation catalyst to improve the decomposition rate of particulate matter. As a result, the amount of power and fuel used to operate the heating device can be reduced by 70%. This is due to the development effect of the high activity catalyst extended from 4 hours to 20 hours of the existing regeneration cycle.

The catalyst, Korean Patent Application No. 10-2009-0038462 (mixing catalyst for the exhaust gas reducing device of diesel vehicles and a method of manufacturing the same), Korean Patent Application No. 10-2008-0126650 (binary for nitrogen monoxide decomposition and oxidation Functional catalyst and its preparation method), and international patent application PCT / KR2009 / 007422 (a binary functional catalyst for nitrogen monoxide decomposition and oxidation, a mixed catalyst for an exhaust gas reducing device comprising the same, and a preparation method thereof).

In the case of particulate matter generated in a vehicle, in particular, a vehicle that has been used for more than 10 years has a large variation in particulate matter generation depending on its maintenance state, and the average vehicle speed may be further reduced according to the concentration of large cities in the population. Is in the view. Therefore, when the development of a compact and compact heat source generator is completed, the present invention is expected to be utilized as a composite regeneration device for post-treatment when it is combined with a catalyst of a previously applied composition.

SUMMARY OF THE INVENTION An object of the present invention for solving the above problems is to provide an exhaust gas purification apparatus for a diesel vehicle having a fuel injection device on top of a post-treatment device composed of a diesel oxidation catalyst coated with a highly active catalyst and a diesel particle filter. do. Accordingly, it is possible to provide an exhaust gas aftertreatment device having a low device configuration ratio and an operation cost.

The catalyst used in the present invention was developed by the present inventors (Korean Patent Application No. 10-2009-0038462, Korean Patent Application No. 10-2008-0126650, International Patent Application PCT / KR2009 / 007422), and has excellent oxidation power. Even under operating conditions, since the PM collection amount is very small, it is possible to give a regeneration period of 20 hours or more. In particular, in the present invention, since the regeneration cycle is improved to 30 hours or more through the change in the coating amount of the previously developed catalyst, in most operating conditions, the probability of exposure to the heating conditions is extremely low. A heat source was generated in the catalyst 300 to add a function of heating the exhaust gas.

In the present invention, a fuel injection device is provided on the inlet side of the DOC / cDPF device coated with a catalyst having excellent decomposition force of the particulate matter. As a result, most of the particulate matter may be spontaneously regenerated. However, depending on the condition of the vehicle and road conditions, the particulate matter is collected by more than its own decomposition amount, thereby preventing the increase of the amount of the particulate matter.

FIG. 2 is a configuration of an exhaust gas purifying apparatus in which a forced regeneration method or a combined regeneration method and a natural regeneration method are mixed. The injection means 200, which is provided in the progress direction sequentially, the soluble material (SOF, Soluble Organic Fraction) contained in the smoke and the diesel oxidation catalyst (DOC, 300) for burning the injection fuel, and particulate matter Diesel particulate filter (DPF, 400) to collect is configured to include.

Exhaust gas purifying apparatus of the present invention includes a diesel oxidation catalyst coated with a catalyst for the exhaust gas reducing device that serves to increase the temperature of the exhaust gas by burning the injected fuel and a diesel particle filter for reducing particulate matter.

In addition, the exhaust gas purification device includes a fuel and air injector at the front end of the diesel oxidation catalyst, the injector has a flange-shaped tube form so that one side is connected to the exhaust pipe and the other side can be connected to the diesel oxidation catalyst can. A housing, a fuel and air injection nozzle located inside the housing, and a supply unit controlling fuel and air supply to the injection nozzle.

The supply unit is a fuel pump connected to the fuel tank for supplying the fuel, an air compressor for supplying air, a fuel auxiliary tank connected to the fuel pump, and a mixer connected to the air compressor to mix air and fuel, respectively, It includes a solenoid valve for adjusting the supply amount, it is controlled by the air compressor, the fuel pump and the solenoid valve control unit (hereinafter ECU).

In addition, a fuel / air preheating means for preheating the incoming fuel / air may be formed in the fuel / air supply line between the fuel / air supply unit and the fuel / air injector.

And a control method of controlling the injection of fuel / air through the fuel / air injection nozzle in the exhaust gas purifier, wherein the injector stops operation of stopping the fuel / air injector for the exhaust gas purifier; A first reference time lapse determining step of determining whether a first reference time has elapsed after the operation of the injection means is confirmed; driving the fuel pump and the air compressor when the first reference time has elapsed; And a second reference time elapsed determination step of determining whether the elapsed time has elapsed, and when the second reference time elapses, returning to the injector operation stop step of stopping the fuel / air injector for the exhaust gas purification device again. do.

The first reference time is characterized in that the conditions, such as the temperature, pressure and speed of each portion in the exhaust gas conduit in the exhaust gas purification apparatus for fuel / air injection is satisfied, the second reference time is In the exhaust gas purifier system, after the fuel / air injection, the particulate matter in the diesel oxidation catalyst and the diesel particle filter is removed to satisfy the condition that the pressure of the system is lowered.

In addition, the exhaust gas purifying apparatus in the present invention is characterized in that it comprises a diesel oxidation catalyst and a diesel particle filter coated with the catalyst for the exhaust gas reducing device to have a role of raising the temperature of the exhaust gas discharged.

In addition, the catalyst coated on the diesel oxidation catalyst and the diesel particle filter is invented by the present inventors as described above (Korean Patent Application No. 10-2008-0126650, Korean Patent Application No. 10-2009-0038462, International Patent application PCT / KR2009 / 007422), titanium (Ti), zirconium (Zr), silicon (Si), aluminum (Al), an oxide containing any one or more components selected from the group of cerium (Ce) as a support, On the support is supported a promoter of any one or more metals or metal oxides selected from the group of tungsten (W), molybdenum (Mo), cobalt (Co), manganese (Mn), copper (Cu), iron (Fe), The active metal of any one or more metals or metal oxides selected from the group of platinum (Pt), palladium (Pd), rhodium (Rh), ruthenium (Ru), silver (Ag) is supported on the promoter, and is dried and fired. And then obtaining a catalyst powder and mixing the catalyst powder with a dispersant A library screen and then, after the coating on the emission reduction apparatus diesel oxidation catalyst and a diesel particulate filter of a diesel vehicle, and the scanning for the vehicle application, and applies it to the diesel exhaust gas reducing device.

Through the present invention, it is possible to provide a small and medium-sized one-type composite device capable of reducing 90% or more of particulate matter by removing risks of the natural regeneration post-treatment device. In particular, the exhaust gas purifying apparatus of the diesel vehicle according to the present invention can provide a post-treatment composite apparatus that achieves a mountability, minimizes fuel / electricity consumption rate, and lowers the device configuration cost.

1 is a schematic diagram of a PM and nitrogen oxide purification system.
2 is a simplified configuration diagram of an exhaust gas purifying apparatus according to the present invention.
3 is a simplified configuration diagram in which a diesel oxidation catalyst and a diesel particle filter are modularized in the exhaust gas purification device of FIG. 2.
4 is a configuration diagram of a fuel / air injection nozzle unit of the exhaust gas purification device of FIG. 2.
5 is a block diagram showing a control method of the exhaust gas purifying apparatus according to the present invention.
6A is a graph of NOx decomposition efficiency according to temperature according to oxygen concentration and GHSV change.
Figure 6b is a diagram showing the concentration of NO ₂ production by temperature according to the oxygen concentration and GHSV change.
7 is a graph showing the PM oxidation reaction according to the change of NOx concentration.
FIG. 8 shows the PM removal efficiency according to the time of PM removal efficiency at an average running speed of 60 km / hr after attaching the diesel oxidation catalyst coated with Pt-W / TiO ₂ and the diesel particulate filter of the preparation example to the vehicle. It is shown. Here, (a) shows DOC loading of 50 g / L of catalyst coating amount, and (b) shows PM collection amount of DOC of 25 g / L of catalyst coating amount.
FIG. 9 is a graph showing a temperature change according to driving of a fuel / air injector of a diesel oxidation catalyst / diesel particle filter coated with Pt-W / TiO ₂ by driving a fuel / air injector during operation as a test example.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. In adding reference numerals to components of the following drawings, it is determined that the same components have the same reference numerals as much as possible even if displayed on different drawings, and it is determined that they may unnecessarily obscure the subject matter of the present invention. Detailed descriptions of well-known functions and configurations will be omitted.

Exhaust gas purification apparatus 2000 of the diesel vehicle according to an embodiment of the present invention is a fuel / air injector 200 sequentially located in the exhaust gas exhaust pipe 110 discharged from the engine 100 as shown in FIG. And a diesel oxidation catalyst 300 coated with an exhaust gas purification catalyst and a diesel particle filter 400.

The fuel / air injector 200, the diesel oxidation catalyst 300, and the diesel particle filter 400 may be formed as a tubular housing in which a fixing part such as a flange is formed such that both sides are connected to the exhaust pipe 110. .

The exhaust gas purifier 2000 is a fuel / air injection device 200 having a tubular housing having fixed parts connected to both sides of the exhaust gas exhaust pipe 110, and a diesel oxidation catalyst coated with a catalyst for the exhaust gas purifier. 300 and the diesel particle filter 400 is located. A reducing agent supply device (not shown) may be additionally installed in the diesel oxidation catalyst 300 or the diesel particle filter 400.

The diesel oxidation catalyst 300 and the diesel particle filter 400 may be configured as one diesel catalyst filter module 302 by integrally combining, as in the exhaust gas purification device 3000 shown in FIG. Through this configuration, the overall size of the exhaust gas purification system 3000 can be reduced.

Referring to FIG. 4, the fuel / air injector 200 has a tubular housing 201 as described above, and is coupled to both ends of the housing 201 for connection with the exhaust pipe 110. A flange 203 with a sphere 202 is formed. The fuel / air injection nozzle 210 is located at the center of the upstream side (part close to the engine 100) in the housing 201 toward the downstream side.

The fuel / air injection nozzle 210 is connected to the fuel / air supply line 220, and the fuel / air supply line 220 is connected to the fuel / air supply unit 240 and the fuel / air supply unit 240. Fuel / air preheating means 230 are arranged to preheat the supplied fuel / air. As the fuel / air preheating means 230, a heat exchanger surrounding the fuel / air supply line 220 or a heater contacting fuel / air directly in the fuel / air supply line 220 may be used.

The fuel / air supply amount is controlled by the ECU 10, and the ECU 10 is installed in the fuel / air supply unit 240 as shown in FIGS. 2 and 3. The fuel / air supply unit 240 may be configured as shown in a box form in FIGS. 2 and 3, and may be modified in various forms. The fuel / air supply unit 240 is connected to the fuel tank 21 in which fuel is stored, the fuel pump 20 connected to the fuel tank 21 to supply fuel, and the fuel pump 20 A fuel auxiliary tank 22 for returning surplus fuel to the fuel tank 21, an air compressor 30 for supplying air, and an air compressor 30 and the fuel auxiliary tank 22, A mixer 40 for mixing fuel, an injector 50 for delivering the fuel / air mixed in the mixer 40 to the fuel supply line 220, and the fuel / air from the injector 50. The air supply unit 240 is configured to include a check valve 23 to allow only the movement of the fuel / air.

Accordingly, the fuel / air delivered from the injector 50 is injected into the housing 201 by the fuel / air injection nozzle 210 via the fuel / air supply line 220 as described above.

The fuel / air injected through the fuel / air injection nozzle 210 is oxidized in the diesel oxidation catalyst (DOC) 300 to raise the temperature of the exhaust gas included in the exhaust gas, and by the high temperature exhaust gas. The particulate matter collected in the diesel particle filter 400 can be reduced to regenerate.

Fuel / air injected through the nozzle 210 depends on the state of FIG. 5. Fuel / air injected through the fuel / air injection nozzle 210 is controlled by the ECU 10, and the control sequence is as follows.

First, at start-up, the operation of the fuel / air injector 200 is stopped (S101). After the start, it is determined whether the first reference time has elapsed, and the state of stopping the fuel / air injector 200 is maintained until the first reference time (S102). In step S102, the elapsed condition of the first reference time is determined by whether the temperature, pressure, speed, etc. measured in each part of the exhaust gas conduit in the exhaust gas purification system 200 coincides with a preset first reference value. .

The temperature measuring part installed to measure the temperature is provided with a temperature sensor downstream of the fuel / air injection nozzle 210, after the diesel oxidation catalyst 300, and after the diesel particle filter 400, respectively. The temperature sensor installed on the downstream side of the fuel / air injection nozzle 210 is disposed in proximity to the fuel / air injection nozzle 210 within 10 cm. The pressure measuring unit for measuring the pressure is installed at the front end of the diesel oxidation catalyst 300, or includes a pressure sensor installed at the rear of the diesel particle filter 400. The speed measurement may utilize information obtained from a commercially available GPS.

When the condition of the first reference time is satisfied, the fuel pump 20 and the air compressor 30 start driving by the ECU 10 (S103). Accordingly, the fuel / air sent from the injector 50 of the fuel / air supply unit 240 is injected into the fuel / air injector 200 through the fuel / air injection nozzle 210, thereby purifying the exhaust gas purifier. The particulate matter trapped inside the diesel particulate filter 400 by raising the temperature of the rear end of the diesel oxidation catalyst 300 coated with a catalyst for the catalyst and raising the temperature of the exhaust gas flowing into the diesel particulate filter 400. Remove it.

Then, it is checked whether or not the second reference time determined that all the particulate matter trapped inside the diesel particle filter 400 has been removed (S104). The second reference time is conditioned on the pressure of the system measured by the pressure measuring unit reaching a predetermined second reference value. At this time, the pressure of the second reference value is the particulate matter in the diesel oxidation catalyst 300 and the diesel particulate filter 400 after the fuel / air injection in the fuel / air injector 200 is regenerated so that the pressure of the system As the pressure lowers, it is lower than the pressure of the first reference value.

The fuel / air injection timing at the first reference time is characterized in that the temperature in the exhaust gas conduit, that is, the temperature of the fuel / air injection nozzle portion and the front / rear of the DOC is 230 ° C. or higher, preferably 250 ° C. or higher. .

And, the fuel / air injection stop point at the second reference time, characterized in that the temperature of the rear end of the diesel particulate filter 400 is 300 ~ 550 ℃, preferably 450 ~ 550 ℃.

Application of the temperature range to the first reference time and the second reference time is associated with the production of NO ₂ shown in FIG. 6. This high on, NO decomposition and NO ₂ produced directly as shown in the patent the two-way function and a method of manufacturing a catalyst for decomposing nitrous oxide and Application (Republic of Korea Patent Application No. 10-2008-0126650 No.) by the present inventors The activity can be maximized as a dual function catalyst that is expressed simultaneously. At 250 ~ 400 ℃, which is the exhaust gas temperature distribution of diesel vehicles, the binary functional catalyst has excellent decomposition efficiency of nitrogen oxide, no activity decrease according to reaction time, and Excellent durability. When some of the NO is oxidized to NO ₂ and supplied to the downstream diesel particle filter, it plays a decisive role in the oxidation of PM trapped in the filter.

As shown in FIG. 6B, the concentration of NO ₂ is increased to 300 ° C. and then decreased after 350 ° C. FIG. Particularly, the oxidation of particulate matter is attributed to nitrogen oxide, and it is obvious when comparing the picture of FIG. 7 according to Test Example 1, and therefore, PM collected in the diesel particle filter in the regeneration temperature condition of 250 ° C. to 400 ° C. temperature range. High oxidation activity can be obtained. That is, not a form in which the other in proportion to the oxidation catalyst and the otherwise increase in the temperature increase in the PM oxidizing power, since the PM oxidation rate determined by the NO ₂ production amount and heated to the NO ₂ production amount with the high temperature range at the same time and improve PM oxidation rate Fuel consumption can be minimized.

The diesel oxidation catalyst 300 and the diesel particle filter 400 is coated with a catalyst for the exhaust gas purification device.

The catalyst coated on the diesel oxidation catalyst 300 and the diesel particle filter 400 is according to the following manufacturing example, titanium (Ti), zirconium (Zr), silicon (Si), aluminum (Al), An oxide containing at least one component selected from the group of cerium (Ce) is used as a support, and on the support is tungsten (W), molybdenum (Mo), cobalt (Co), manganese (Mn), copper (Cu), iron A promoter of any one or more metals or metal oxides selected from the group of (Fe) is supported, and platinum (Pt), palladium (Pd), rhodium (Rh), ruthenium (Ru), silver (Ag) on the promoter Supporting the active metal of any one or more metals or metal oxides selected from the group of to obtain a catalyst powder after drying and calcining; And mixing the catalyst powder with a dispersant.

The catalyst coated on the diesel oxidation catalyst 300 and the diesel particle filter 400 is for simultaneously removing nitrogen oxide and particulate matter having a dual function of nitrogen dioxide generation through carbon monoxide oxidation, nitrogen monoxide decomposition and nitrogen monoxide oxidation. It was developed as a catalyst (see Korean Patent Application Nos. 10-2008-0126650, 10-2009-0038462, and International Patent Application PCT / KR2009 / 007422).

The diesel oxidation catalyst 300 is coated with a slurry by wet milling the catalyst. Appropriate coating amount is 10-70g / L, preferred coating amount is 10-50g / L, more preferable coating amount is 10-30g / L.

The coating amount is in the range of maximizing the oxidation rate of the particulate matter, the manufacturing cost saving part is an additional advantage. The catalyst according to the present invention aims at the formation of NO ₂ , which is a medium required for the oxidation of particulate matter at the same time as nitrogen oxide decomposition. That is, since the increase in the amount of catalyst coating appears as an increase in the amount of nitrogen oxide decomposition, the total amount of NO ₂ produced decreases. Therefore, excessive increase in the amount of catalyst coating is effective in terms of nitrogen oxide decomposition, but in the case of driving vehicle application purpose (satisfaction with Euro IV), the PM oxidation rate is reduced, so it is necessary to respond according to the engine type of the vehicle.

The above contents can be clearly understood in Test Example 3. As shown in FIG. 8, in the case of the diesel oxidation catalyst 300 having the catalyst coating amount of 50 g / L (see FIG. 8 (a)), the PM collection rate 0.98 g / hr (PM decomposition rate 80.4% at a low speed of 60 km / hr or less) On the other hand, when the results of experiments equipped with a diesel oxidation catalyst 300 having a catalyst coating amount of 25 g / L (see FIG. 8 (b)), the PM capture rate is lowered to 0.5 g / hr (PM decomposition rate 90.0%). You can see the result.

As described above, the present invention has been described with reference to preferred examples and embodiments of the present invention, but those skilled in the art can variously change the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. It will be appreciated that modifications and variations can be made.

[Manufacturing Example]

The manufacturing process of the catalyst for reducing the exhaust gas of the diesel vehicle for coating on the diesel oxidation catalyst 300 and the diesel particle filter 400 will be described by way of example.

Titanium dioxide (TiO ₂ ) was dried at 105 ° C. for 12 hours, cooled to room temperature, tungsten was supported as a promoter, and platinum was supported as an active metal. The activated metal-supported titanium dioxide was dried at 105 ° C. for 12 hours, and then calcined in an air atmosphere at 550 ° C. to obtain a catalyst powder (Pt-W / TiO ₂ ).

The Pt-W / TiO ₂ was mixed with distilled water and wet pulverized in an attrition mill for 60 minutes to obtain an average particle diameter of 100 nm or less to obtain a catalyst slurry for the exhaust gas reducing device of the diesel vehicle of the present invention. . The distilled water was used as a dispersant.

[Coating example]

A process of coating the diesel oxidation catalyst 300 and the diesel particle filter 400 using the catalyst (Pt-W / TiO ₂ ) according to the preparation example will be described as an example.

In this embodiment, the diesel oxidation catalyst and the diesel particle filter were coated using the catalyst slurry shown in Preparation Example.

First, Cordierite diesel oxidation catalyst (14 cm in diameter and 2.4 L in volume) was coated with 50 g and 25 g per unit volume (1 L), respectively, and the diesel particle filter (14 cm in diameter and 5.6 L in volume) was used as a unit. Per volume (1 L), 20 g was coated.

Next, the catalyst slurry coated with the diesel oxidation catalyst and the diesel particle filter was dried for 10 hours at 105 ℃, and then fired for 4 hours at 550 ℃ air atmosphere. Subsequently, the mixture was reduced at 300 ° C. for 2 hours under the condition that 20% by volume of H ₂ / N ₂ mixed gas flowed. As a result, a diesel oxidation catalyst and a diesel particle filter coated with Pt-W / TiO ₂ were obtained.

[Test Example 1]

The powder catalyst according to the Preparation Example was granulated to 40/80 mesh size, and the nitrogen oxide decomposition power and NO ₂ production were measured after 1 hour reduction in a 300 ° C. hydrogen atmosphere. The experiment was conducted under the conditions similar to the exhaust gas composition of diesel vehicle, with 5 ~ 15% O ₂ , 5% CO ₂ , 300ppm NOx, N ₂ balance and 5% H ₂ O, GHSV = 12,500 ~ 100,000 hr ^-1 . . As a result of the NOx decomposition efficiency and NO ₂ production concentration according to the oxygen concentration and the GHSV change shown in FIG. 6, it can be seen that the GHSV change is more affected than the decrease in activity caused by the oxygen concentration. This shows the difference in activity of the catalyst according to the change in the exhaust gas air flow rate under the actual operating conditions.

As shown in FIG. 6B, the amount of NO ₂ produced increased rapidly up to 350 ° C. and then decreased.

[Test Example 2]

The effect of nitrogen oxides in the PM oxidation process of the powder catalyst according to the preparation example was measured.

10 wt% of vehicle-generated PM was added to the powder catalyst for mortar mixing for 5 minutes, and granulated to 40/80 mesh particle size to measure PM oxidation rate. Supply gas conditions are as follows.

Reaction condition 1: oxygen 15%, moisture 5%, nitrogen oxides (NO) 0, 300, 600, 900ppm, nitrogen balance gas

The PM oxidation rate was performed in a micro reactor having an inner diameter of 4 mm. The CO ₂ concentration discharged from the reactor was analyzed at 5 minute intervals using gas chromatography while heating at a rate of 1 ° C./min in the reaction temperature range of 200-400 ° C.

As shown in FIG. 7, in the reaction conditions in which nitrogen oxide is added, the amount of carbon dioxide is increased from 220 ° C., while in the reaction conditions in which nitrogen oxide is not added, carbon dioxide is not generated even at 400 ° C. Appeared. These results indicate that the PM oxidation reaction in this catalyst is caused by nitrogen oxides.

[Test Example 3]

Vehicle equipped with a 3.0 L TCl engine by canning the diesel oxidation catalyst coated with Pt-W / TiO ₂ (50 g / L coating) and the diesel particle filter prepared in the above-described manufacturing example to be attached to the vehicle. The cumulative amount of PM per running hour was measured in a condition of 60 km / hr or less and the speed was shown in FIG. 9.

For vehicle operation, the PM trapping weight change in the filter was measured for 4 times of 13 hours and once of 13 hours of operation. As shown in (a) of FIG. 8, the PM removal efficiency of the diesel oxidation catalyst coated with Pt-W / TiO ₂ and the diesel particle filter according to the preparation example reaches 80.4%.

That is, it can be seen that the PM removal efficiency of the diesel oxidation catalyst and the diesel particle filter coated with the catalyst of the present invention is excellent.

[Test Example 4]

Vehicle equipped with a 3.0 L TCl engine by canning a diesel oxidation catalyst coated with Pt-W / TiO ₂ (25 g / L coating) and a diesel particle filter prepared in the above-described manufacturing example to be attached to the vehicle. The cumulative amount of PM per running hour was measured in the condition of the driving speed of 60 km / hr or less, and is shown in FIG.

For vehicle operation, the PM collection weight change in the filter was measured for two times of operation every 4 hours and 2 hours. As shown in (b) of FIG. 8, the PM removal efficiency of the diesel oxidation catalyst coated with Pt-W / TiO ₂ and the diesel particulate filter prepared in Preparation Example reaches 90.0%.

That is, it can be seen that the effect of PM oxidation rate is very large depending on the amount of catalyst coating on DOC. In particular, it can be seen that by reducing the amount of coating can improve the PM oxidation rate and economical efficiency at the same time.

[Test Example 5]

While driving the vehicle under the conditions according to the test example 2, the fuel / air injector 240 according to the present invention was operated to conduct a heating experiment of the diesel particle filter 400.

Fuel was injected under conditions where the DOC inlet / outlet temperature was 250 ° C or higher. The injection quantity was controlled in the temperature range 350-450 degreeC of the rear end of the filter 400.

Experimental results, as shown in Figure 9, it was possible to heat the temperature of the diesel oxidation catalyst and diesel particle filter to the appropriate range through fuel / air injection.

10: ECU 20: fuel pump
21: fuel tank 22: fuel auxiliary tank
23: check valve 30: air compressor
40: mixer 50: injector
100: engine 110: exhaust pipe
112: discharge line 200: fuel / air injector
201: housing 202: fastener
203: flange 210: fuel / air injection nozzle
220: fuel / air injection pipe 230: fuel / air preheating means
240: fuel / air supply unit 300: diesel oxidation catalyst (DOC)
400: diesel particulate filter (DPF) 500: selective reduction catalyst (SCR catalyst)
1000, 2000, 3000: exhaust gas purification device

Claims (9)

A fuel / air injector 200 installed in the exhaust pipe 110 connected to the engine 100 to inject fuel / air into the exhaust gas;
A diesel oxidation catalyst 300 installed at a rear end of the fuel / air injector 200 to increase the temperature of exhaust gas through the fuel / air injected by the fuel / air injector 200; And
Located at the rear end of the diesel oxidation catalyst 300 includes a diesel particle filter 400 for removing particulate matter,
The fuel / air injector 200 includes a tubular housing 201 that forms a body and is connected to the exhaust pipe 100;
A fuel / air injection nozzle 210 disposed at an upstream center of the housing 201 and injecting fuel / air toward a downstream side; And
It is connected by the fuel / air injection nozzle 210 and the fuel / air supply line 220, and includes a fuel / air supply unit 240 for supplying and blocking fuel / air,
A fuel / air preheating means 230 is installed between the fuel / air supply unit 240 and the fuel / air injection nozzle 210.
The fuel / air supply unit 240 is connected to the fuel tank 21 in which fuel is stored, the fuel pump 20 connected to the fuel tank 21 to supply fuel, and the fuel pump 20 A fuel auxiliary tank 22 for returning surplus fuel to the fuel tank 21, an air compressor 30 for supplying air, and an air compressor 30 and the fuel auxiliary tank 22, A mixer 40 for mixing fuel, an injector 50 for delivering the fuel / air mixed in the mixer 40 to the fuel / air supply line 220, and the injector 50 from the injector 50. And a check valve (23) allowing only the movement of fuel / air to the fuel / air supply unit (240).
delete delete In the control method for controlling the exhaust gas purification device of claim 1,
Step a) the operation of the fuel / air supply unit 240 is stopped;
Step b) determining the elapse of the first reference time in the stop state of the fuel / air supply unit 240;
Step c) after the first reference time has elapsed, operating the fuel / air supply unit 240 to inject fuel / air through the fuel / air injection nozzle 210;
Step d) determining the passage of the second reference time in the stop state of the fuel / air supply unit 240; And
Step e) returning to step a if the second reference time has elapsed in step d.
The method of claim 4, wherein the first reference time is any one of the temperature and pressure of at least one of the exhaust pipe 110, the fuel / air injection device 200, the diesel oxidation catalyst 300, and the diesel particle filter 400. And at least one of the speeds reaches the first reference value, and the second reference time determines that the pressure of the diesel oxidation catalyst 300 or the diesel particle filter 400 reaches the second reference value. A control method for an exhaust gas purification device, characterized in that.
The method of claim 4, wherein the first reference time is characterized in that at least one of the temperature of the diesel oxidation catalyst 300 and the diesel particulate filter 400 has reached 230 ° C. Control method of the exhaust gas purification device.
5. The control method according to claim 4, wherein the second reference time is determined that the temperature at the rear end of the diesel particle filter reaches a range of 300 to 550 ° C.
In the catalyst for removing nitrogen oxides and particulate matter provided in the diesel oxidation catalyst 300 and the diesel particulate filter 400 of the exhaust gas purification device of claim 1,
Titanium (Ti), zirconium (Zr), silicon (Si), aluminum (Al), cerium (Ce) is an oxide containing any one or more components selected from the group as a support, tungsten (W), molybdenum on the support (Mo), cobalt (Co), manganese (Mn), copper (Cu), a promoter of any one or more metals or metal oxides selected from the group of iron (Fe) is supported, platinum (Pt) on top of the promoter , Palladium (Pd), rhodium (Rh), ruthenium (Ru), the catalyst for removing nitrogen oxides and particulate matter, characterized in that the active metal of any one or more metals or metal oxides selected from the group of supported.
The method of claim 1, wherein the diesel oxidation catalyst 300, at least one selected from the group consisting of titanium (Ti), zirconium (Zr), silicon (Si), aluminum (Al), cerium (Ce) An oxide is used as a support, and at least one metal or metal oxide selected from the group consisting of tungsten (W), molybdenum (Mo), cobalt (Co), manganese (Mn), copper (Cu), and iron (Fe) on the support The promoter is supported, and the active metal of any one or more metals or metal oxides selected from the group of platinum (Pt), palladium (Pd), rhodium (Rh), ruthenium (Ru), silver (Ag) on the promoter An exhaust gas purification apparatus for a diesel vehicle, characterized in that the coating for removing the nitrogen oxide and particulate matter, characterized in that supported by the powder form 10-50g / L.

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