KR101534699B1 - System and method of desulfurizing denitrification catalyst - Google Patents

Abstract

The present invention relates to a desulfurization apparatus and a desulfurization method for a nitrogen oxide reduction catalyst that prevent degradation of the performance of a nitrogen oxide reduction catalyst by providing a recommended route through which desulfurization of the nitrogen oxide reduction catalyst can proceed when desulfurization of the nitrogen oxide reduction catalyst is required .
The desulfurization method of the NOx reduction catalyst may include: determining whether the navigation device searches for a route; Determining whether desulfurization of the nitrogen oxide reduction catalyst is necessary; Recommending a path capable of desulfurizing the nitrogen oxide reduction catalyst when desulfurization of the nitrogen oxide reduction catalyst is required; Determining whether the vehicle is traveling on a recommended route; Determining whether the desulfurization condition of the NOx reduction catalyst is satisfied if the NOx reduction catalyst is running on the recommended route; And advancing desulfurization of the nitrogen oxide reduction catalyst when the desulfurization condition of the nitrogen oxide reduction catalyst is satisfied.

Description

TECHNICAL FIELD [0001] The present invention relates to a desulfurization apparatus and a desulfurization method for a nitrogen oxide reduction catalyst,

The present invention relates to a desulfurization apparatus and a desulfurization method for a nitrogen oxide reduction catalyst, and more particularly, to a method for desulfurizing a nitrogen oxide reduction catalyst, To a desulfurization apparatus and a desulfurization method for a nitrogen oxide reduction catalyst.

Generally, the exhaust gas discharged from the engine through the exhaust manifold is guided to a catalytic converter installed in the exhaust pipe, purified, passed through a muffler to attenuate noise, and then discharged to the atmosphere through a tail pipe. The above-described catalytic converter purifies pollutants contained in the exhaust gas. A soot filter for collecting particulate matters (PM) contained in the exhaust gas is mounted on the exhaust pipe.

A denitrification catalyst (DeNOx Catalyst) is a type of catalytic converter that purifies nitrogen oxides (NOx) contained in exhaust gases. When a reducing agent such as Urea, Ammonia, Carbon Monoxide and Hydrocarbon (HC) is supplied to the exhaust gas, the nitrogen oxide contained in the exhaust gas is oxidized and reduced by the reducing agent .

In recent years, an LNT catalyst (Lean NOx Trap Catalyst) has been used as such a nitrogen oxide reduction catalyst. The LNT catalyst adsorbs the nitrogen oxides contained in the exhaust gas when the engine is operated in a lean atmosphere and desorbs the adsorbed nitrogen oxides when the engine is operated in a rich atmosphere.

The nitrogen oxide reduction catalyst includes a basic substance for adsorbing nitrogen oxide. However, since sulfur oxides are also acidic, sulfur oxides are adsorbed on the nitrogen oxide reduction catalyst. This is called sulfur poisoning.

When the nitrogen oxide reduction catalyst is poisoned by sulfur, the basic substance is combined with the sulfur oxide to absorb the nitrogen oxide, and the performance of the nitrogen oxide reduction catalyst is lowered. Therefore, the sulfur oxides adsorbed on the nitrogen oxide reduction catalyst must be desorbed. This is called desulfurization.

In order to desulfurize the nitrogen oxide reduction catalyst, the temperature of the exhaust gas must be very high. In order to raise the temperature of the exhaust gas to a temperature capable of desulfurizing the nitrogen oxide reduction catalyst, the vehicle must run at least at a medium speed or a high speed, and some drivers operate the vehicle only at a low speed. Therefore, the nitrogen oxide reduction catalyst is poisoned and the performance can not be exhibited properly.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and it is an object of the present invention to provide a nitrogen oxide reduction catalyst capable of performing desulfurization of a nitrogen oxide reduction catalyst when desulfurization of the nitrogen oxide reduction catalyst is required, And a desulfurization apparatus and a desulfurization method of a nitrogen oxide reduction catalyst which prevent the desulfurization of the catalyst.

According to an aspect of the present invention, there is provided a desulfurization apparatus for a NOx reduction catalyst, the apparatus comprising: an exhaust pipe through which exhaust gas flows; a nitrogen oxide reduction / desorption apparatus for selectively adsorbing or desorbing nitrogen oxides contained in exhaust gas; catalyst; A vehicle speed sensor for measuring the vehicle speed; A navigation device for presenting a route from a current location to a destination; A Global Positioning System (GPS) that receives radio waves from satellites and transmits the signals to the navigation device; A telematics device for receiving traffic information from a center; A sulfur concentration estimating unit estimating an amount of sulfur poisoned in the nitrogen oxide reduction catalyst; And a controller connected to the vehicle speed sensor, the navigation device, the GPS, the telematics device, and the sulfur concentration estimator to control the desulfurization of the nitrogen oxide reduction catalyst, wherein the controller controls the nitrogen oxide reduction catalyst It is necessary to determine whether desulfurization of the nitrogen oxide reduction catalyst is required or not, and if it is necessary to desulfurize the nitrogen oxide reduction catalyst, it is possible to control the navigation apparatus to recommend a path capable of desulfurization of the nitrogen oxide reduction catalyst.

The controller determines whether or not the engine is running on a recommended route and determines whether the desulfurization condition of the NOx reduction catalyst during the running is satisfied with the recommended route. If the desulfurization condition of the NOx reduction catalyst is satisfied, the desulfurization of the NOx reduction catalyst proceeds .

The controller may determine whether a desulfurization difficulty condition is present, stop the desulfurization if the desulfurization difficulty condition exists, and end the desulfurization process if the desulfurization stop time exceeds the set time.

The desulfurization difficulty condition may be traffic congestion or downhill running.

The controller can determine if a desulfurization end condition exists and terminate the desulfurization if the desulfurization end condition exists.

The desulfurization termination condition may be satisfied if it arrives at the destination or before the first predetermined time to enter the tunnel.

The controller can proceed desulfurization of the nitrogen oxide reduction catalyst if it is traveling on a road where desulfurization is possible even if it does not travel on a recommended route.

The method for desulfurizing a nitrogen oxide reduction catalyst according to another embodiment of the present invention includes the steps of: determining whether a navigation device searches for a route; Determining whether desulfurization of the nitrogen oxide reduction catalyst is necessary; Recommending a path capable of desulfurizing the nitrogen oxide reduction catalyst when desulfurization of the nitrogen oxide reduction catalyst is required; Determining whether the vehicle is traveling on a recommended route; Determining whether the desulfurization condition of the NOx reduction catalyst is satisfied if the NOx reduction catalyst is running on the recommended route; And advancing the desulfurization of the nitrogen oxide reduction catalyst when the desulfurization condition of the nitrogen oxide reduction catalyst is satisfied.

Wherein the desulfurization method comprises: determining whether a desulfurization difficulty condition exists during desulfurization; Stopping desulfurization if a desulfurization difficulty condition exists; Determining whether the desulfurization stop time exceeds a set time; And terminating the desulfurization if the desulfurization stop time exceeds the set time.

The desulfurization difficulty condition may be traffic congestion or downhill running.

Wherein the desulfurization method comprises the steps of: determining whether a desulfurization termination condition exists for progressing desulfurization; And terminating the desulfurization if the desulfurization termination condition exists.

The desulfurization termination condition may be satisfied if it arrives at the destination or before the first predetermined time to enter the tunnel.

Determining whether the desulfurization possible road is running on the desulfurized road even if the desulfurization method does not run on a recommended route; And proceeding the desulfurization if the desulfurization possible road is running.

As described above, according to the present invention, when the desulfurization of the nitrogen oxide reduction catalyst is required, it is possible to prevent degradation of the performance of the nitrogen oxide reduction catalyst by providing a recommended route for advancing the desulfurization of the nitrogen oxide reduction catalyst.

1 is a schematic view showing an example of an exhaust apparatus to which a desulfurization method for a NOx reduction catalyst according to an embodiment of the present invention can be applied.
2 is a block diagram of a desulfurization apparatus for a nitrogen oxide reduction catalyst according to an embodiment of the present invention.
3 is a flowchart of a desulfurization method of a nitrogen oxide reduction catalyst according to an embodiment of the present invention.

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

1 is a schematic view showing an example of an exhaust apparatus to which a desulfurization method for a NOx reduction catalyst according to an embodiment of the present invention can be applied.

1, an exhaust system of an internal combustion engine includes an engine 10, an exhaust pipe 20, an exhaust gas recirculation (EGR) apparatus 80, a particulate filter 30, A nitrogen oxide reduction catalyst 40, and a controller 50.

The engine 10 converts chemical energy into mechanical energy by burning a mixture in which fuel and air are mixed. The engine 10 is connected to the intake manifold 18 to receive air into the combustion chamber 12 and the exhaust gas generated in the combustion process is collected in the exhaust manifold 16 and then discharged from the engine. An injector 14 is mounted in the combustion chamber 12 to inject fuel into the combustion chamber 12.

Here, a diesel engine is exemplified, but a lean burn gasoline engine may be used. When a gasoline engine is used, the mixer is introduced into the combustion chamber 12 through the intake manifold 18, and an ignition plug (not shown) for ignition is mounted on the combustion chamber 12.

Further, an engine having various compression ratios, preferably compression ratios of 16.5 or less, can be used.

The exhaust pipe 20 is connected to the exhaust manifold 16 to exhaust the exhaust gas to the outside of the vehicle. A soot filter 30 and a nitrogen oxide reduction catalyst 40 are mounted on the exhaust pipe 20 to remove hydrocarbons, carbon monoxide, particulate matter, and nitrogen oxides contained in the exhaust gas.

The exhaust gas recirculation device 80 is mounted on the exhaust pipe 20 to re-supply a part of the exhaust gas discharged from the engine 10 to the engine through the exhaust gas recirculation device 80. The exhaust gas recirculation device 80 is connected to the intake manifold 18 to control the combustion temperature by mixing a part of the exhaust gas with air. Such control of the combustion temperature is performed by controlling the amount of exhaust gas supplied to the intake manifold 18 under the control of the controller 50. [

A first oxygen sensor 25 is mounted on the rear exhaust pipe 20 of the exhaust gas recirculation device 80 to detect the amount of oxygen in the exhaust gas that has passed through the exhaust gas recirculation device 80.

The nitrogen oxide reduction catalyst 40 is mounted on the exhaust pipe 20 at the rear of the exhaust gas recirculation device 80 so that when the engine 10 is operated in a lean atmosphere, When the engine 10 is operated in a rich atmosphere, the adsorbed nitrogen oxide is desorbed and the reducing reaction proceeds to purify the nitrogen oxide contained in the exhaust gas. Here, it is exemplified that the LNT catalyst is used as the nitrogen oxide reduction catalyst 40.

A first temperature sensor 35 is mounted on the front exhaust pipe 20 of the nitrogen oxide reduction catalyst 40 to measure an inlet temperature of the nitrogen oxide reduction catalyst 40, A second temperature sensor 36 is mounted to measure an outlet temperature of the nitrogen oxide reduction catalyst 40 or an inlet temperature of the soot filter 30. [ Here, the nitrogen oxide reduction catalyst 40 may be composed of a plurality of portions having different ratios of the coated metal. This is to allow the carrier to perform a specific function by varying the proportion of the metal coated. For example, by increasing the ratio of palladium (Pd) to the first portion close to the engine 10, the heat-resistant function is enhanced, and by increasing the ratio of platinum Pt to the second portion close to the tail pipe, Can be prevented. Alternatively, the same nitrogen oxide reduction catalyst 40 may be used in the entire region of the metal coated on the carrier.

The particulate filter (30) is mounted on the exhaust pipe (20) behind the nitrogen oxide reduction catalyst (40). The particulate filter 30 may be a diesel particulate filter (DPF) 30 and collect particulate matters (PM) contained in the exhaust gas discharged through the exhaust pipe 20. Here, the particulate filter 30 has the same meaning as the particulate filter 30. However, other types of soot filters 30 (e.g., catalyzed particulate filters (CPF)) may be used instead of the soot filtering apparatus 30. [

In addition, the soot filter 30 may be coated with an oxidation catalyst. This oxidation catalyst oxidizes hydrocarbons and carbon monoxide contained in the exhaust gas to carbon dioxide and oxidizes nitrogen monoxide contained in the exhaust gas to nitrogen dioxide. The oxidation catalyst may be coated on a certain portion of the particulate filter 30 or may be uniformly coated on the entire area of the particulate filter 30. [

On the other hand, a differential pressure sensor 55 is mounted on the exhaust pipe 20. The differential pressure sensor 55 measures the pressure difference between the front end and the rear end of the particulate filter 30 and transmits a signal to the controller 50. The controller 50 may control the particulate filter 30 to regenerate when the pressure difference measured by the differential pressure sensor 55 is equal to or greater than the first set pressure. In this case, the particulate matter trapped in the particulate filter 30 can be burned by injecting fuel at the injector 14.

The controller 50 determines the operation condition of the engine based on the signals detected by the sensors and controls the fuel addition injection amount and the additional injection timing based on the operation condition of the engine to adsorb the nitrogen oxide reduction catalyst 40 Nitrogen oxides are desorbed. In addition, the controller 50 estimates the amount of sulfur poisoned in the nitrogen oxide reduction catalyst 40 and controls the desulfurization of the nitrogen oxide reduction catalyst 40 based on the estimated amount of sulfur.

2 is a block diagram of a desulfurization apparatus for a nitrogen oxide reduction catalyst according to an embodiment of the present invention.

2, a desulfurization apparatus for a nitrogen oxide reduction catalyst according to an embodiment of the present invention includes a differential pressure sensor 55, a vehicle speed sensor 100, a navigation device 110, a GPS (Global Positioning System) A telematics device 130, a sulfur concentration estimation unit 140, a controller 50, and an injector 14.

The differential pressure sensor 55 measures the pressure difference between the front and rear ends of the soot filter 33.

The vehicle speed sensor 100 measures the speed of the vehicle and is mounted on the wheel of the vehicle. Alternatively, the vehicle speed may be calculated based on the GPS signal received by the GPS 120.

The navigation device 110 is a device for notifying a driver of a route to a destination. The navigation device 100 is provided with an input / output unit for inputting and outputting information related to route guidance, a current position detection unit for detecting information on the current position of the vehicle, a memory for storing map data necessary for route calculation and data necessary for guidance, And a control unit for executing route guidance. The map data may be wirelessly or wired to the navigation device 110 at an information center or a telematics center.

The GPS 120 receives the radio waves transmitted from the GPS satellites and transmits a signal to the navigation device 110. Based on the radio wave, the navigation device 110 calculates the current position of the vehicle.

The telematics device 130 receives environmental information such as traffic information, GPS information, and weather from the telematics center and uses the information to control various devices of the vehicle.

The sulfur poisoning estimating unit 130 estimates the amount of sulfur poisoned in the nitrogen oxide reduction catalyst 40. The sulfur content of the nitrogen oxide reduction catalyst 40 is estimated on the basis of the fuel injection amount, the engine operation history, the nitrogen oxide purification rate, and the like.

The controller 50 is electrically connected to the differential pressure sensor 55, the vehicle speed sensor 100, the navigation device 110, the GPS 120, the telematics device 130, and the sulfur concentration estimator 130 . The controller 50 may be implemented with one or more processors operating by a program that is programmed to perform each step of the desulfurization method of the NOx reduction catalyst 40 according to an embodiment of the present invention Lt; / RTI >

3 is a flowchart of a desulfurization method of a nitrogen oxide reduction catalyst according to an embodiment of the present invention.

As shown in FIG. 3, the desulfurization method of the NOx reduction catalyst according to the embodiment of the present invention starts when the navigation device 110 operates (S200).

The navigation device 110 determines whether the user searches for a route (S210), and forwards the signal to the controller 50.

If the user does not search for the route, the controller 50 controls the vehicle to perform normal traveling (S310), and terminates the desulfurization method of the nitrogen oxide reduction catalyst according to the embodiment of the present invention.

If the user searches for a route, the controller 50 determines whether desulfurization of the nitrogen oxide reduction catalyst 40 is necessary based on the estimated sulfur content of the nitrogen oxide reduction catalyst 40 estimated by the sulfur oxide content estimation unit 130 (S220). The controller 55 determines whether or not the regeneration of the particulate filter 30 is necessary based on the signal of the differential pressure sensor 55 and determines that the regeneration of the particulate filter 30 is necessary for the desulfurization. This is because a very high temperature (for example, 600 DEG C) is required for desulfurization of the nitrogen oxide reduction catalyst 40, and in order to raise the temperature of the exhaust gas to a temperature capable of desulfurizing under the normal operation condition of the engine, And this leads to deterioration of fuel efficiency. Therefore, when regenerating the particulate filter 30, the fuel is injected a little more so as to proceed to the desulfurization.

If it is not necessary to desulfurize the nitrogen oxide reduction catalyst 40, the controller 50 controls the vehicle so as to perform the general running (S310), and ends the desulfurization method of the nitrogen oxide reduction catalyst according to the embodiment of the present invention.

If it is necessary to desulfurize the nitrogen oxide reduction catalyst 40, the controller 50 controls the navigation device 110 to search for a route to a destination including a desulfurization possible route of the nitrogen oxide reduction catalyst 40, The navigation apparatus 110 recommends a route to a destination including a path capable of desulfurizing the nitrogen oxide reduction catalyst 40 (S230).

Thereafter, the controller 50 determines whether the vehicle is traveling on a recommended route (S240).

If the vehicle is traveling on the recommended route, the controller 50 determines whether the desulfurization condition of the NOx reduction catalyst 40 is satisfied (S250). That is, it is determined whether the vehicle is traveling on a road that can travel at medium or high speed for a predetermined time or more.

If the desulfurization condition of the NOx reduction catalyst 40 is not satisfied in step S250, the controller 50 continues to determine whether the desulfurization condition of the NOx reduction catalyst 40 is satisfied (S250).

If the desulfurization condition of the NOx reduction catalyst 40 is satisfied in step S250, the controller 50 controls the injector 14 to proceed desulfation of the NOx reduction catalyst 40 (S260). That is, the fuel is post-injected to raise the temperature of the exhaust gas.

Thereafter, the controller 50 determines whether the desulfurization is completed (S270).

If the desulfurization is completed, the controller 50 proceeds to step S300 to terminate the desulfurization and terminate the desulfurization method of the NOx reduction catalyst according to the embodiment of the present invention.

If the desulfurization is not completed, the controller 50 continues the desulfurization of the nitrogen oxide reduction catalyst 40 and determines whether there is a desulfurization difficult condition (S280). The desulfurization difficulty condition may be traffic congestion or downhill running. That is, when the vehicle can not be speeded up due to sudden road congestion or the fuel cut control is performed on the downhill road, the desulfurization of the nitrogen oxide reduction catalyst 40 can not proceed, and it is determined that there is a desulfurization difficulty condition in this case.

If the desulfurization difficulty condition does not exist in step S280, the controller 50 determines whether a desulfurization termination condition exists (S290). Hydrogen sulphide generated during desulfurization is a colorless, toxic gas that smells of egg rot. Users can smell and complain when the desulfurization occurs in an indoor building, a car park, or a tunnel. Therefore, the desulfurization process is terminated before entering a place such as an indoor building, a parking lot, or a tunnel, thereby enhancing the merchantability. For this purpose, the desulfurization termination condition may be satisfied when it arrives at the destination or before the first predetermined time to enter the tunnel.

If the desulfurization termination condition does not exist in step S290, the controller 50 returns to step S260 to continue the desulfurization of the NOx reduction catalyst 40. [

If the desulfurization termination condition exists in step S290, the controller 50 terminates the desulfurization (S300), and ends the desulfurization method of the nitrogen oxide reduction catalyst according to the embodiment of the present invention.

On the other hand, if there is a desulfurization difficulty condition in step S280, the controller 50 stops the desulfurization (S340) and determines whether the desulfurization stop time exceeds the set time (S350).

If the desulfurization stop time is less than the set time, the controller 50 returns to step S280 and determines whether the desulfurization difficult condition continues to exist.

If the desulfurization stop time exceeds the set time, the controller 50 terminates the desulfurization (S300) and terminates the desulfurization method of the nitrogen oxide reduction catalyst according to the embodiment of the present invention. This is because if the desulfurization is stopped so that the set time is exceeded, there is no difference in the fuel efficiency between the continuation of the desulfurization which has been stopped due to the lowered temperature of the exhaust gas and the progress of the desulfurization.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, And all changes to the scope that are deemed to be valid.

Claims (13)

A nitrogen oxide reduction catalyst mounted on an exhaust pipe through which exhaust gas flows and selectively storing or desorbing nitrogen oxide contained in the exhaust gas;
A vehicle speed sensor for measuring the vehicle speed;
A navigation device for presenting a route from a current location to a destination;
A Global Positioning System (GPS) that receives radio waves from satellites and transmits the signals to the navigation device;
A telematics device for receiving traffic information from a center;
A sulfur concentration estimating unit estimating an amount of sulfur poisoned in the nitrogen oxide reduction catalyst; And
A controller connected to the vehicle speed sensor, the navigation device, the GPS, the telematics device, and the sulfur content estimator to control the desulfurization of the nitrogen oxide reduction catalyst;
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Wherein the controller determines whether desulfurization of the nitrogen oxide reduction catalyst is necessary at the time of route search and controls the navigation apparatus to recommend a path capable of desulfurizing the nitrogen oxide reduction catalyst when desulfurization of the nitrogen oxide reduction catalyst is required,
The controller determines whether the engine is running on a recommended route, determines whether the desulfurization condition of the NOx reduction catalyst during the running is satisfied with the recommended route, and proceeds to the desulfurization of the NOx reduction catalyst when the desulfurization condition of the NOx reduction catalyst is satisfied In addition,
Wherein the controller determines whether a desulfurization difficulty condition exists, and when the desulfurization difficulty condition exists, the desulfurization is stopped, and if the desulfurization stop time exceeds the set time, the desulfurization is terminated. delete delete The method according to claim 1,
Wherein the desulfurization difficulty condition is a traffic congestion or a downhill running. The method according to claim 1,
Wherein the controller determines whether a desulfurization termination condition exists, and terminates the desulfurization if the desulfurization termination condition exists. 6. The method of claim 5,
Wherein the desulfurization termination condition is satisfied when it reaches a destination or before a first predetermined time to enter the tunnel. The method according to claim 1,
Wherein the controller advances the desulfurization of the nitrogen oxide reduction catalyst if the controller is running on a road where desulfurization is possible even if the controller does not run on a recommended route. Determining whether the navigation device searches for a route;
Determining whether desulfurization of the nitrogen oxide reduction catalyst is necessary;
Recommending a path capable of desulfurizing the nitrogen oxide reduction catalyst when desulfurization of the nitrogen oxide reduction catalyst is required;
Determining whether the vehicle is traveling on a recommended route;
Determining whether the desulfurization condition of the NOx reduction catalyst is satisfied if the NOx reduction catalyst is running on the recommended route; And
A step of advancing desulfurization of the nitrogen oxide reduction catalyst when the desulfurization condition of the nitrogen oxide reduction catalyst is satisfied;
Lt; / RTI >
Determining whether a desulfurization difficulty condition exists during desulfurization;
Stopping desulfurization if a desulfurization difficulty condition exists;
Determining whether the desulfurization stop time exceeds a set time; And
Terminating the desulfurization if the desulfurization stop time exceeds the set time;
Further comprising a desulfurizing step of desulfurizing the nitrogen oxide. delete 9. The method of claim 8,
Wherein the desulfurization difficulty condition is a traffic congestion or a downhill running. 9. The method of claim 8,
Determining whether a desulfurization termination condition exists during the desulfurization; And
Terminating the desulfurization if the desulfurization termination condition exists;
Further comprising a desulfurizing step of desulfurizing the nitrogen oxide. 12. The method of claim 11,
Wherein the desulfurization termination condition is satisfied when the exhaust gas reaches the destination or before the first predetermined time to enter the tunnel. 9. The method of claim 8,
Determining whether the vehicle is traveling on a desulfurizable road even if the vehicle is not traveling on a recommended route; And
Progressing the desulfurization if the desulfurization possible road is running;
Further comprising a desulfurizing step of desulfurizing the nitrogen oxide.

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