KR102054214B1 - System for after-treatment of exhaust gas, and method for controlling of the same - Google Patents

Abstract

The present invention provides a system for post-treatment of an exhaust gas which is mounted on an exhaust pipe of an internal combustion engine and sequentially has, on the upstream side, a diesel particulate matter filter (DPF) and a selective catalyst reduction (SCR) technology. The system further includes: a burner positioned upstream of the DPF to heat an exhaust gas from the internal combustion engine; a hydrocarbon injector positioned upstream of the DPF to spray hydrocarbon to the exhaust gas; and a control unit controlling the burner and the hydrocarbon injector according to a first mode for removing nitrogen oxides or a second mode for removing particulates. When the temperature of the exhaust gas does not reach the operating temperature of the SCR, the control unit operates the burner according to the first mode to heat the exhaust gas to the operating temperature of the SCR, or operates the burner while spraying hydrocarbon by using the hydrocarbon injector according to the second mode to heat the exhaust gas to the particle removal temperature of the DPF. Thus, the system can use a small-capacity burner and hydrocarbon injection, thereby extending an operating area thereof to a low-temperature area.

Description

Exhaust gas aftertreatment system and control method {SYSTEM FOR AFTER-TREATMENT OF EXHAUST GAS, AND METHOD FOR CONTROLLING OF THE SAME}

The present invention relates to an exhaust gas aftertreatment system and a control method thereof, and more particularly, to an exhaust gas aftertreatment system and a control method thereof for purifying exhaust gas discharged from an internal combustion engine mounted on a vehicle.

In general, the demand for diesel engines capable of driving high efficiency and high power in vehicles, ships, generators, etc. continues to increase. This is because diesel oil is inexpensive and has advantages in terms of fuel efficiency and efficiency.

When driving such a diesel engine, NOx and Particulate Matter (PM), which cause air pollution, are included in the exhaust gas and exhausted, so a smoke reduction device must be installed to reduce the exhaust gas.

Typically, a particulate collecting device (DPF) for collecting particulate matter (PM) to purify exhaust gas discharged from an internal combustion engine, ammonia generated from urea water, and the like as a reducing agent are nitrogen oxides (NO _x ). And a selective reduction catalyst (SCR) for purifying the same.

Since the particulate collecting device or the selective reduction catalyst device operates based on the catalyst function, the particulate collecting device or the selective reduction catalyst device operates depending on the temperature of the exhaust gas emitted from the internal combustion engine. Therefore, there is no problem in the exhaust gas purification function due to the high catalytic activity in the high speed and high load driving environment, but in low speed low load vehicles or vehicles with frequent stops and go, the exhaust gas temperature is low to operate the aftertreatment system normally. It is difficult to cause the problem that the emission of harmful exhaust gas increases.

Therefore, various methods for raising the exhaust gas have been developed and used, but in order to increase the exhaust gas temperature by using the burner, the fuel injection amount and the flame are increased so that the size and structure of the burner are complicated, which makes it difficult to operate and install the components. There is a problem that frequently occurs and malfunction of the operation.

In addition, in the case of a large vehicle having a large exhaust flow rate, the fuel injection amount is large, so that it is difficult to control an initial slip and the like, and it is difficult to achieve stable regeneration efficiency.

Therefore, there is a need for a technology that can solve these problems.

KR 10-1826556 B1

The present invention is to provide an exhaust gas aftertreatment system and a control method thereof, which can extend the operating region of the exhaust gas aftertreatment system to a low temperature region by using a small capacity burner and hydrocarbon injection.

In order to solve the above problems, the present invention is mounted on the exhaust pipe of the internal combustion engine, the exhaust gas having a particulate particulate collection device (DPF) and a selective catalytic reduction (SCR) in order upstream A post-treatment system comprising: a burner located upstream of the particulate collecting device for heating up the exhaust gas of the internal combustion engine, a hydrocarbon injector located upstream of the particulate collecting device for injecting hydrocarbon into the exhaust gas; And a control unit for controlling the burner and the hydrocarbon injector according to a first mode for removing nitrogen oxides or a second mode for removing particulates, wherein the control unit is configured to control the selective reduction catalyst device to have a temperature of the exhaust gas. If it does not reach the operating temperature of, the burner in accordance with the first mode to operate the exhaust gas Increase the temperature to the operating temperature of the selective reduction catalyst device, or inject the hydrocarbon using the hydrocarbon injector according to the second mode and at the same time operating the burner to increase the temperature to remove the particulates of the particulate collecting device To provide an exhaust gas aftertreatment system.

According to one embodiment, the control unit, when the temperature of the exhaust gas is higher than the operating temperature of the selective reduction catalyst device, do not operate the burner and the hydrocarbon injector according to the first mode, or to the second mode Accordingly, the burner and / or the hydrocarbon injector may be used to increase the temperature to remove the fine particles of the fine particle collecting device.

According to one embodiment, the control unit, according to the second mode, when there is no hydrocarbon slip, by heating the exhaust gas only by the hydrocarbon injection using the hydrocarbon injector, when the hydrocarbon slip occurs, the burner and the hydrocarbon The injector may be used to heat up the exhaust gas.

According to one embodiment, the control unit, by using the burner in accordance with the first mode can increase the exhaust temperature of the exhaust gas to the particulate collecting device 300 ℃ or more.

According to one embodiment, the burner may be a mini-burner capable of raising the exhaust gas by 100 ° C or less.

According to one embodiment, the control unit, by using the burner and the hydrocarbon injector in accordance with the second mode can increase the exhaust temperature of the exhaust gas to the particulate collecting device 400 ℃ or more.

In addition, the present invention provides an exhaust gas aftertreatment system equipped with a particulate particulate collection device (DPF) and a selective catalytic reduction device (SCR), which are mounted in an exhaust pipe of an internal combustion engine and sequentially upstream. In the control method, the control unit comprises a burner according to a first mode for removing nitrogen oxides or a second mode for removing particulates, wherein the burner is located upstream of the particulate collecting device to exhaust the exhaust gas of the internal combustion engine. And a hydrocarbon injector, wherein the hydrocarbon injector is located upstream of the particulate collecting device and injects hydrocarbon into the exhaust gas, wherein the controlling step includes: If the temperature does not reach the operating temperature of the selective reduction catalyst device, the burner is operated in accordance with the first mode to Raising the gas to an operating temperature of the selective reduction catalyst device, or injecting a hydrocarbon using the hydrocarbon injector according to the second mode, and simultaneously operating the burner to raise the temperature to the particle removal temperature of the particulate collecting device. A control method of an exhaust gas aftertreatment system is provided.

The exhaust gas aftertreatment system and control method thereof according to the present invention can extend the operating region of the exhaust gas aftertreatment system to a low temperature region by using a small capacity burner and hydrocarbon injection.

According to the control mode, the burner can operate the mini burner at maximum duty in the forced regeneration mode and at the lowest duty in the nitrogen oxide reduction mode to minimize fuel economy of the mini burner.

In the high speed driving mode of the engine, that is, under high load conditions, hydrocarbon injection alone can lead to regeneration of the DPF and reduction of nitrogen oxides. The particulate matter can be reduced by raising the temperature to a renewable temperature.

1 is a block diagram of an exhaust gas aftertreatment system according to an exemplary embodiment of the present invention.
Figure 2 is a graph showing the temperature measured in the exhaust gas aftertreatment system when simulating low speed operation.
3 is a graph showing the temperature measured in the exhaust gas aftertreatment system in the DPF regeneration mode of low speed operation.
Figure 4 is a graph showing the temperature measured in the aftertreatment system measured in the exhaust gas aftertreatment system of low-speed operation in the nitrogen oxide reduction mode.
Figure 5 is a step-by-step flowchart of the operation method of the exhaust gas aftertreatment system according to an embodiment of the present invention.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments disclosed herein will be described in detail with reference to the accompanying drawings, and the same or similar components will be given the same reference numerals regardless of the reference numerals, and redundant description thereof will be omitted. The suffixes "module" and "unit" for components used in the following description are given or mixed in consideration of ease of specification, and do not have distinct meanings or roles from each other. In addition, in describing the embodiments disclosed herein, when it is determined that the detailed description of the related known technology may obscure the gist of the embodiments disclosed herein, the detailed description thereof will be omitted. In addition, the accompanying drawings are intended to facilitate understanding of the embodiments disclosed herein, but are not limited to the technical spirit disclosed herein by the accompanying drawings, all changes included in the spirit and scope of the present invention. It should be understood to include equivalents and substitutes.

When a component is said to be "connected" or "connected" to another component, it may be directly connected to or connected to that other component, but it may be understood that another component may be present in the middle. Should be. On the other hand, when a component is said to be "directly connected" or "directly connected" to another component, it should be understood that there is no other component in between.

Singular expressions include plural expressions unless the context clearly indicates otherwise.

In this specification, the terms "comprises" or "having" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

Exhaust gas aftertreatment system

1 is a block diagram of an exhaust gas aftertreatment system according to an exemplary embodiment of the present invention. As shown in FIG. 1, an exhaust gas aftertreatment system according to an exemplary embodiment of the present invention is mounted on an exhaust pipe of an engine 10, which is an internal combustion engine, and has a particulate particulate filter (DPF) in sequence from an upstream side. A burner (23) and a selective catalytic reduction (SCR) device (31), which is located upstream of the particulate collecting device (23) for heating the exhaust gas of the engine (10); 21), a hydrocarbon injector 41 located upstream of the particulate collecting device 23 for injecting hydrocarbon (HC) into the exhaust gas, and a first mode or particulate for removing the nitrogen oxide; According to a second mode for the control unit 50 for controlling the burner 21 and the hydrocarbon injector 41 may be included.

It is a matter of course that the components shown in FIG. 1 are not essential, so that an exhaust gas aftertreatment system having more or fewer components can be implemented.

Hereinafter, each component will be described.

The particulate collecting device 23 is mounted to an exhaust pipe through which exhaust gas discharged from the engine 10 passes, and the particulate collecting device 23 collects most of particulate matter (PM; Particulate Matter) contained in the exhaust gas, Through the exhaust gas can be purified to the outside.

The particulate collecting device 23 may be, for example, a filter plugged alternately with the inlet and the outlet of the porous ceramic honeycomb cell in order to collect particulate matter contained in the exhaust gas. In the process of exhaust gas flowing into the inlet of the unplugged cell, passing through the cell wall for collecting particulate matter (PM) formed at the boundary with the adjacent non-plugged cell, and exiting the outlet of the unplugged cell, The cell walls will trap particulate matter (PM).

That is, although the particulate matter collecting device 23 physically collects particulate matter in the exhaust gas of the engine 10 by using a filter, the amount of capture that can be collected is limited, so that the particulate matter collecting device 23 has a high temperature. Through forced regeneration by passing the exhaust gas to burn off the trapped particulate matter, it is possible to restore the trapping ability of the particulate matter.

A burner 21 is located on the upstream side of the particulate matter collecting device 23, and the exhaust gas flowing into the particulate matter collecting device 23 can be heated to raise the temperature. In order to heat the exhaust gas, electricity or microwaves may be used, but the type thereof is not particularly limited.

At this time, since the burner 21 according to the embodiment of the present invention may be capable of raising the exhaust gas by about 100 to 150 ° C., it is preferable that the burner 21 is a mini burner having a small amount of fuel injection and a small flame size. In the present specification, the expression "about" includes a range exceeding a small amount or less than a small amount based on the temperature, and even including a temperature within the range.

According to an embodiment, a diesel oxidation catalyst (DOC) 22 may be positioned upstream of the particulate collecting device 23.

The diesel oxidation catalyst device 22 uses a noble metal such as platinum (Pt), palladium (Pd) or rhodium (Rh) as a catalyst to a honeycomb-supported member made of ceramics made of cordierite or the like as oxygen in exhaust gas. (O ₂₎ by the oxidation of hydrocarbons (HC) and carbon monoxide (CO) contained in the exhaust gas, or a soluble organic components contained in the particulate matter; oxidized to (SOF Souluble organic Fraction), water (H ₂ O) and It is a catalytic device that converts carbon dioxide (CO ₂ ).

A hydrocarbon injector 41 may be located upstream of the diesel oxidation catalyst device 22, and the hydrocarbon injector 41 injects hydrocarbons HC into the exhaust pipe, thereby increasing the carbon monoxide and hydrogen components. The heat generation occurs by the oxidation of the exhaust gas introduced into the 22, and the temperature of the exhaust gas flowing into the selective reduction catalyst 31 is raised. Therefore, the ammonia slip reduction and the selective reduction catalyst purification performance can be improved by maintaining the temperature of the exhaust gas flowing into the selective reduction catalyst device 31 above the active temperature even under low temperature and low load rough load conditions.

On the other hand, the selective reduction catalyst device 31 may be located at the rear end (or downstream of the exhaust gas) of the particulate collecting device 23.

The selective reduction catalyst device 31 is a catalyst zeolite, such as iron-doped aluminosilicate, supported on a carrier such as ceramic honeycomb, and is a urea (urea) that is injected by a urea injector 42 located in an upstream exhaust pipe. Or urea water) is converted into ammonia by the heat of the exhaust gas, and nitrogen oxide is converted into nitrogen gas (N ₂ ) and water as a catalytic reaction of nitrogen oxide (NO _x ) and ammonia (NH ₃ ) in the exhaust gas by a selective reduction catalyst. Reduce to (H ₂ O).

To this end, the urea injector 42 may be located at the rear end of the particulate collecting device 23, the operation of the urea injector 42 is controlled by the control unit 50 so that the nitrogen in the selective reduction catalyst device 31 is controlled. In order to purify the oxide (NO _x ) it may be sprayed with an aqueous solution of urea inside the exhaust pipe. In this case, the urea injector 42 may directly inject ammonia, and other reducing agents may be injected in addition to ammonia, or in this case, may be injected together with ammonia.

Here, each of the front and rear ends of the selective reduction catalyst device 31 is provided with a nitrogen oxide sensor (not shown), so that the amount of nitrogen oxide before and after the exhaust gas passes through the selective reduction catalyst device 31 can be measured.

According to one embodiment, the rear end of the selective reduction catalyst 31 further comprises an ammonia slip catalyst device (not shown), by oxidizing ammonia (NH ₃ ) in the exhaust gas nitrogen (N2) and water (H2O) In this case, it is possible to purify the ammonia flowing out of the selective reduction catalyst device 31 to prevent the ammonia from flowing into the atmosphere.

In this case, the ammonia slip catalyst device is similar to the diesel oxidation catalyst device 22, and includes platinum (Pt), palladium (Pd), and rhodium (Rh) in a honeycomb-supported body made of ceramics made of cordierite or the like. Precious metals, such as these, can be comprised as a catalyst.

On the other hand, according to an embodiment of the present invention, the first temperature sensor for detecting the temperature (T1) of the exhaust gas flowing into the diesel oxidation catalyst device 22, and the exhaust gas flowing into the particulate collecting device (23) It may include a second temperature sensor for detecting the temperature (T2), and a third temperature sensor for detecting the temperature (T3) of the exhaust gas flowing out of the particulate collecting device (23).

The controller 50 may receive the detected values T1 to T3 from the first to third temperature sensors, and control the burner 21 or the hydrocarbon ejector 41 based on the detected values T1 to T3.

In addition to this, a control temperature sensor may be added to control the burner 21, and a temperature sensor may be added to monitor the temperature of the rear end of the selective reduction catalyst device 31. In addition, a monitoring pressure sensor may be included upstream of the burner 21 to monitor PM accumulated in the particulate collecting device 23.

The controller 50 may perform the control operation according to the height of the exhaust gas temperature and in two modes. Here, the first mode indicates control for reducing nitrogen oxides, and the second mode indicates control for removing particulate matter (PM).

The switching operation between the first and second modes of the controller 50 may be performed according to a direct input by an external user or a predetermined condition (time, temperature of exhaust gas, flow rate of exhaust gas, concentration of nitrogen oxide, etc.). It can be made automatically, it is not particularly limited thereto.

Specifically, when the temperature T1 of the exhaust gas discharged from the engine 10 is low, and the temperature of the exhaust gas flowing into the selective reduction catalyst device 31 does not reach the active temperature, the burner 21 according to the first mode. ) To maintain the temperature of the exhaust gas flowing into the selective reduction catalyst device 31 above the active temperature, to reduce the nitrogen oxide (NO _x ) discharged, or to operate the burner 21 in accordance with the second mode And the operation of the hydrocarbon injector 41 to induce forced regeneration of the particulate collecting device 23 and at the same time maintain the temperature of the exhaust gas flowing into the selective reduction catalyst device 31 above the active temperature and discharge the nitrogen oxide (NO). ^x ) can be reduced.

Figure 2 is a graph showing the temperature measured in the exhaust gas aftertreatment system when simulating low speed operation.

As shown in FIG. 2, in the case of a low speed low load vehicle or a vehicle with frequent stop & go, the temperature T1 of the exhaust gas discharged from the engine 10 is maintained at 300 ° C. or lower, and particulates are collected. The apparatus 23 is difficult to regenerate naturally due to the exhaust gas temperature, and the exhaust gas temperature T3 on the downstream side of the particulate collecting device 23 does not satisfy the urea dosing condition at 200 ° C. or lower, so that nitrogen is discharged. Oxide NO _x is not reduced.

In this case, when the control unit 50 operates in the first mode, that is, the nitrogen oxide reduction mode, the exhaust gas flowing into the selective reduction catalyst device 31 by operating the burner 21 is selectively reduced catalyst device 31. The temperature of the exhaust gas can be controlled so that the temperature of the exhaust gas is increased to about an operating temperature of? The temperature measured in the exhaust gas aftertreatment system in the low-noise nitrogen oxide reduction mode may be represented as shown in FIG. 4.

That is, by the burner 21 operation, the exhaust gas of about 150 ° C discharged from the engine 10 is heated up to a temperature T2 of about 300 ° C or more at the front end of the particle collecting device 23, and thus, the particulate collecting device 23. Can be naturally regenerated by the exhaust gas temperature, and the front end of the selective reduction catalyst device 31 satisfies urea dosing conditions at a temperature of about 200 ° C. or higher, and thus the reduction rate of nitrogen oxides is 60% by activation of the selective reduction catalyst device 31. This can lead to the above.

In addition, when the controller 50 operates in the second mode, that is, the DPF regeneration mode, the controller 50 controls the hydrocarbon injector 41 so that the temperature T2 of the exhaust gas flowing into the particulate collecting device 23 is about 400 ° C. By using this, the hydrocarbon can be injected into the exhaust gas and the burner 21 can be operated to raise the exhaust gas. The temperature measured in the aftertreatment system measured in the exhaust gas aftertreatment system in the low speed operation DPF regeneration mode may be represented as shown in FIG. 3.

That is, by the injection of hydrocarbons together with the burner 21 operation, the exhaust gas of about 150 ° C discharged from the engine 10 is heated up to a temperature T2 of about 400 ° C or more at the front end of the particle collecting device 23, thereby Forced regeneration of the collecting device 23 by the burning of particulate matter is possible, and at the front end of the selective reduction catalyst device 31, the urea dosing conditions are satisfied at a temperature of about 200 ° C. or higher, and thus activation of the selective reduction catalyst device 31 is performed. Nitrogen oxide reduction rate can reach 60% or more.

According to one embodiment of the present invention, even in low-speed driving, the exhaust gas is heated by stable flame formation using a mini-burner to regenerate the particulate collecting device 23, and the forced regenerating of the particulate collecting device 23 is performed depending on the mode. In the mode, the mini burner is operated at maximum duty, and in the NOx reduction mode, the mini duty is minimized by minimizing fuel economy.

Unlike the foregoing, when the temperature T1 of the exhaust gas discharged from the engine 10 is high and the temperature of the exhaust gas flowing into the selective reduction catalyst device 31 is equal to or higher than the active temperature, the nitrogen oxide which is the first mode is reduced. Depending on the mode, the burner 21 and the hydrocarbon injector 41 are not operated, and only the heat of the exhaust gas discharged from the engine 10 enables the selective reduction catalyst 31 to be activated, or the particulate matter which is the second mode ( Depending on the PM) removal mode, the burner 21 and / or the hydrocarbon injector 41 may be used to allow the exhaust gas in front of the particulate collecting device 23 to be raised to the particulate matter removing temperature of the particulate collecting device 23. .

Specifically, when the temperature T1 of the exhaust gas discharged from the engine 10 is high, the controller 50 operates the hydrocarbon injector 41 when there is no hydrocarbon slip so that the fine particle collecting device 23 is turned on by only hydrocarbon injection. By allowing the exhaust gas to have a temperature T2 of about 400 ° C. or higher at the front end, the particulate matter collecting device 23 can be forcedly regenerated by combustion. According to another embodiment, the hydrocarbon injection may increase the exhaust gas by about 150 ° C., but since the exhaust gas may be heated by about 100 ° C. by operation of the burner 21, the controller 50 may control the engine 10. When the deviation between the temperature T1 of the exhaust gas discharged from the gas and the temperature T2 of the front end of the particulate collecting device 23 is about 100 ° C. or less, only the burner 21 is operated to operate, and the deviation is about 100 to In the case of 150 ° C., only the hydrocarbon injector 41 may be operated.

That is, when the engine 10 is in the high speed traveling mode, that is, the temperature of the exhaust gas is high, it is possible to induce DFP regeneration and nitrogen oxide reduction by only hydrocarbon injection.

On the contrary, when hydrocarbon slip occurs, the hydrocarbon is injected by the operation of the hydrocarbon injector 41 simultaneously with the operation of the burner 21 so that the exhaust gas at the front end of the particulate collecting device 23 has a temperature T2 of about 400 ° C. or more. In this way, the particulate matter collecting apparatus 23 can enable forced regeneration by combustion.

Here, whether the slip of the hydrocarbon is generated or not is controlled by the controller 50, each of the components of the exhaust gas aftertreatment system (diesel oxidation catalyst 22, particulate collecting device 23, selective reduction catalyst 31) and / or It is possible to directly calculate using the amount of heat or loss flowed in and out, or to receive the result calculated by an external device, and the present invention does not particularly limit this.

Exhaust gas aftertreatment method

Figure 5 is a step-by-step flowchart of the operation method of the exhaust gas aftertreatment system according to an embodiment of the present invention.

As shown in FIG. 5, the method for controlling an exhaust gas aftertreatment system according to an embodiment of the present invention includes a particulate collecting device 23 and a selective reduction catalyst device that are mounted on an exhaust pipe of an internal combustion engine and sequentially upstream. 31. In the control method of the exhaust gas aftertreatment system provided with 31), the control unit 50 includes a burner 21 and a hydrocarbon injector according to a first mode for removing nitrogen oxides or a second mode for removing particulates. A control step (S10 ~ S2222) for controlling the 41 may be included.

In the controlling step, the exhaust gas temperature is low, in which the temperature T3 of the exhaust gas before the selective reduction catalyst device 31 or after the particulate collecting device 23 does not reach the operating temperature of the selective reduction catalyst device 31. In this case, by operating the burner 21 according to the first mode (step S2211), the exhaust gas from the front of the selective reduction catalyst device 31 or the rear end of the particulate collecting device 23 is operated by the selective reduction catalyst device 31. The temperature is raised to a temperature to activate the selective reduction catalyst device 31 (step S2212), or the burner 21 is operated simultaneously with the hydrocarbon injection using the hydrocarbon injector 41 according to the second mode (step S2221). By raising the temperature to the particle removal temperature of the particle collecting device 23, both the particle collecting device 23 and the selective reduction catalyst 31 can be activated (step S2222).

Further, according to one embodiment, the control unit 50, the temperature (T3) of the exhaust gas in front of the selective reduction catalyst 31, or the rear end of the particulate collecting device 23 is the operating temperature of the selective reduction catalyst 31. In this case, the selective reduction catalyst 31 is activated (S2112) without the burner 21 and the hydrocarbon injector 41 operating in accordance with the first mode (step S2111), or the burner according to the second mode. (21) and / or the hydrocarbon injector 41 is heated up to the particle removal temperature of the particle collecting device 23 (step S2112) to activate both the particle collecting device 23 and the selective reduction catalyst device 31 (S2222). Step).

Specifically, according to the second mode, when there is no hydrocarbon slip, the controller 50 heats up the exhaust gas only by hydrocarbon injection using the hydrocarbon injector 41, and burner 21 when hydrocarbon slip occurs. And the hydrocarbon injector 41 can be used to increase the temperature of the exhaust gas.

However, the steps shown in FIG. 5 or the steps according to the embodiment of the present invention described above are not essential, and thus a method of controlling the exhaust gas aftertreatment system having more or fewer steps may be implemented. .

Since the description of each step is duplicated with the above description, the description thereof will be omitted and replaced with it.

Computer readable recording media

The method for controlling the exhaust gas aftertreatment system according to the exemplary embodiment of the present invention described above may be implemented in the form of program instructions that can be executed by various computer components and recorded in a computer readable recording medium.

The computer-readable recording medium may include program instructions, data files, data structures, etc. alone or in combination. Program instructions recorded on the computer-readable recording medium may be those specially designed and configured for the present invention, or may be known and available to those skilled in the computer software arts. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks and magnetic tape, optical recording media such as CD-ROMs, DVDs, and magneto-optical media such as floptical disks. media), and hardware devices specifically configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions include not only machine code generated by a compiler, but also high-level language code that can be executed by a computer using an interpreter or the like. The hardware device may be configured to operate as one or more software modules to perform the process according to the invention, and vice versa.

Preferred embodiments of the present invention have been described in detail above with reference to the drawings. The description of the present invention is for illustrative purposes, and it will be understood by those skilled in the art that the present invention may be easily modified in other specific forms without changing the technical spirit or essential features of the present invention.

Therefore, the scope of the present invention is shown by the claims below rather than the detailed description, and all changes or modifications derived from the meaning, scope, and equivalent concepts of the claims are included in the scope of the present invention. Should be interpreted.

10: engine 21: burner
22: diesel oxidation catalyst device 23: particulate collection device
31: selective reduction catalyst 41: hydrocarbon injector
42: urea injector 50: control unit

Claims (7)

In the exhaust gas after-treatment system mounted on the exhaust pipe of the internal combustion engine and equipped with a particulate particulate filter (DPF) and a selective catalytic reduction (SCR) in order from the upstream side,
A burner located on an upstream side of the particulate collecting device for heating the exhaust gas of the internal combustion engine, wherein the burner is a mini burner capable of raising the exhaust gas by 100 ° C. or less;
A hydrocarbon injector positioned upstream of the particulate collecting device and injecting hydrocarbon into the exhaust gas; And
A control unit controlling the burner and the hydrocarbon injector according to a first mode for removing nitrogen oxides or a second mode for removing particulates;
Include more,
If the temperature of the exhaust gas does not reach the operating temperature of the selective reduction catalyst device, the controller operates the burner in the first mode to raise the exhaust gas to the operating temperature of the selective reduction catalyst device. In the second mode, the hydrocarbon is injected using the hydrocarbon injector, and at the same time, the burner is operated to raise the temperature to the particulate removal temperature of the particulate collecting device.
When the temperature of the exhaust gas is equal to or higher than the operating temperature of the selective reduction catalyst device, when the burner and the hydrocarbon injector are not operated in the first mode or there is no hydrocarbon slip in the second mode, When the temperature difference between the exhaust gas discharged from the internal combustion engine and the front end of the particulate collecting device is 100 ° C. or less, only the burner is operated, and the temperature difference between the temperature of the exhaust gas discharged from the internal combustion engine and the front end of the particulate collecting device. If the 100 ~ 150 ℃ exhaust gas after-treatment system, characterized in that for operating only the hydrocarbon injector. delete delete The method of claim 1,
The control unit, when the temperature of the exhaust gas does not reach the operating temperature of the selective reduction catalyst device, by using the burner in the first mode to increase the shear temperature of the particulate collecting device to 300 ℃ or more Exhaust aftertreatment system. delete The method of claim 1,
The control unit, after the exhaust gas post-treatment system, using the burner and / or the hydrocarbon injector in the second mode to raise the front end temperature of the particulate collecting device to 400 ℃ or more. In the control method of the exhaust gas after-treatment system mounted on the exhaust pipe of the internal combustion engine and equipped with a particulate particulate filter (DPF) and a selective catalyst reduction (SCR) in order from the upstream side,
The control unit may include a burner according to a first mode for removing nitrogen oxides or a second mode for removing particulates, wherein the burner is positioned upstream of the particulate collecting device to raise the exhaust gas of the internal combustion engine. A control step of controlling a mini-burner capable of heating the exhaust gas by 100 ° C. or less, and a hydrocarbon injector, wherein the hydrocarbon injector is located upstream of the particulate collecting device and injects hydrocarbon into the exhaust gas;
Including,
The control step,
When the temperature of the exhaust gas does not reach the operating temperature of the selective reduction catalyst device, the burner is operated in the first mode to raise the exhaust gas to the operating temperature of the selective reduction catalyst device or the second temperature. In the mode, the hydrocarbon injector using the hydrocarbon injector and at the same time operating the burner to increase the temperature of the particulate removal of the particulate collecting device,
The control step,
When the temperature of the exhaust gas is higher than the operating temperature of the selective reduction catalyst device, when the burner and the hydrocarbon injector are not operated in the first mode or there is no hydrocarbon slip in the second mode, the internal combustion engine When the temperature difference between the exhaust gas discharged and the front end of the particulate collecting device is 100 ° C. or less, only the burner is operated, and the temperature difference between the exhaust gas exhausted from the internal combustion engine and the front end of the particulate collecting device is 100 to 150. The control method of the exhaust gas aftertreatment system, characterized in that for operating only the hydrocarbon injector.

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