KR20180045687A - Sdpf system preventing ammonia odor during regeneration and control method thereof - Google Patents

Abstract

The present invention relates to an SDPF system preventing ammonia odor during regeneration and a control method thereof so as to prevent ammonia odor from being emitted due to exhaust of ammonia sealed in SDPF during regeneration. According to the present invention, the method of controlling the SDPF system, which has an SDPF (14) for purifying soot and nitrogen oxides contained in exhaust gas discharged from an engine (11) of a vehicle, and an urea water injector (15) for injecting urea water into the SDPF (14) so as to prevent ammonia odor during regeneration, includes: a temperature increase start step (S110) of starting to increase the temperature of the SDPF (14) in order to regenerate the SDPF (14); an ammonia removal temperature arrival determination step (S130) of determining whether the temperature of the SDPF (14) reaches the ammonia removal temperature which is set to be lower than the regeneration temperature of the SDPF (14); an urea water injection stopping step (S140) of blocking the urea water from being injected into the SDPF (14) while maintaining the SDPF (14) at the ammonia removal temperature; and an SDPF regeneration step (S160) of regenerating the SDPF (14) while maintaining the SDPF regeneration temperature.

Description

Technical Field [0001] The present invention relates to an SDPF system and a control method thereof,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an SDPF (SCR ON DIESEL PARTICULAR FILTER) for removing nitrogen oxide (NOx) from an exhaust gas of a vehicle, and more particularly to a phenomenon in which ammonia occluded in SDPF is discharged during reproduction to generate ammonia odor To prevent the smell of ammonia during regeneration.

Various post-treatment devices have been applied to reduce various harmful substances contained in the exhaust gas of the vehicle.

For example, as shown in FIG. 1, a diesel oxidation catalyst (DOC) 12 or a lean NOx trap (LNT) 12 is installed in an exhaust pipe 12 through which exhaust gas is exhausted to the engine 11 , And an SDPF (SCR ON DIESEL PARTICULAR FILTER) is installed downstream thereof.

In the SDPF, a DPF (DIESEL PARTICULAR FILTER) for removing soot is coated with an SCR catalyst material, thereby performing removal of NOx while removing the soot contained in the exhaust gas.

The element stored in the urea water tank 16 is injected through the urea water injector 15 provided at the front end of the SDPF 14 in order to remove NOx from the SDPF 14. [

Meanwhile, since the SDPF 14 also removes the soot contained in the exhaust gas, if the soot is excessively deposited in the SDPF 14, the soap is regenerated through regeneration.

The SDPF 14 raises the temperature of the exhaust gas to a predetermined temperature, for example, 600 ° C or higher during the regeneration, and maintains the temperature for a predetermined period of time. At this time, when the SDPF 14 is regenerated in a state in which the vehicle is stopped, the exhaust gas is not scattered, but remains around the vehicle, so that ammonia occluded in the SDPF 14 is discharged to generate an odor . For example, when the SDPF 14 is over deposited, an engine warning light on the instrument panel lights up or a warning light for alarming an abnormality of the SDPF 14 is turned on, and after entering into the repair shop of the vehicle, . The exhaust gas is not dispersed to the surroundings, and the surroundings are maintained, and the SCR catalyst included in the SDPF 14 has a characteristic of discharging ammonia stored at a high temperature Therefore, when the SDPF 14 is regenerated in a stopped state, the ammonia is discharged to cause an odor. As shown in FIG. 4, as the temperature of the SDPF 14 rises, the ammonia storage amount in the SDPF 14 is lowered. Therefore, in order to regenerate the SDPF 14, When the temperature is raised, the ammonia occluded in the SDPF 14 is discharged.

As a result, workers or people in the vicinity of the repair shop feel uncomfortable due to the smell of ammonia.

On the other hand, the following prior art documents disclose a technique related to 'SDPF and its manufacturing method'.

KR 10-1338068 B1

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a method and apparatus for preventing the discharge of ammonia occluded in the SDPF during the regeneration of the SDPF by consuming ammonia stored in the SDPF An object of the present invention is to provide an SDPF system in which ammonia odor is prevented during regeneration and a control method thereof.

In order to accomplish the above object, the present invention provides an SDPF system in which ammonia odor is prevented from being regenerated by regeneration of a DPF (DIESEL PARTICULAR FILTER) in order to remove soot and nitrogen oxide contained in exhaust gas exhausted from an engine of a vehicle, The SDPF system includes a SDPF coated with a selective catalytic reduction catalyst material and injects urea water through an urea water injector installed at a front end of the SDPF. The SDPF system includes a temperature sensor installed in the SDPF and measuring the temperature of the SDPF And when the temperature of the SDPF inputted from the temperature sensor reaches the ammonia removing temperature set lower than the regeneration temperature of the SDPF before the SDPF is regenerated, the urea water is supplied to the SDPF while maintaining the SDPF at the ammonia removing temperature The operation of the urea water injector is stopped so that the exhaust gas reacts with the ammonia occluded in the SDPF It was characterized by a control unit for regenerating the temperature was raised to the SDPF the following removal of the ammonia within the SDPF.

Further comprising an ammonia storage amount sensor installed in the SDPF for measuring the amount of ammonia stored in the SDPF and outputting the amount of ammonia stored in the SDPF to the control unit, wherein when the amount of stored ammonia is 0 , And raising the temperature of the SDPF to the regeneration temperature of the SDPF to regenerate the SDPF.

And the ammonia removing temperature is set to 250 to 300 캜.

The controller stops the injection of urea water from the urea water injector while maintaining the SDPF at the ammonia removal temperature when it is determined that the vehicle is stopped.

On the other hand, the control method of the SDPF system in which the smell of ammonia is prevented during regeneration includes SDPF for purifying soot and nitrogen oxide contained in the exhaust gas discharged from the engine of the vehicle, and urea water injector for injecting urea water into the SDPF The method comprising the steps of: starting a temperature rise of the SDPF to regenerate the SDPF; and determining whether the temperature of the SDPF has reached the ammonia removal temperature set lower than the regeneration temperature of the SDPF A urea water injection stopping step of stopping injection of urea water into the SDPF while maintaining the SDPF at the ammonia removing temperature, and a urea water injection stopping step of maintaining the SDPF at the ammonia removing temperature, And an SDPF reproduction step of reproducing the SDPF.

Further comprising an ammonia removal completion determination step of determining whether all of the ammonia occluded in the SDPF is removed between the urea water injection stopping step and the SDPF regeneration step, wherein ammonia adsorbed in the SDPF in the ammonia removal completion determination step The SDPF playback step is performed.

And determining whether ammonia has been completely removed from the SDPF while maintaining the stop of urea water injection by the SDPF when it is determined that the ammonia has not been removed in the ammonia removal completion determination step.

And the ammonia removing temperature is set to 250 to 300 ° C in the step of determining the ammonia removing temperature.

And determining whether the temperature of the SDPF reaches the ammonia removal temperature when it is determined that the temperature of the SDPF does not reach the ammonia removal temperature in the step of determining the ammonia removal temperature.

Further comprising a vehicle stop determining step of determining whether the vehicle is stopped between the starting of the temperature rising step and the step of determining the arrival of the ammonia removing temperature, wherein when it is determined that the vehicle is stopped, And a temperature arrival judgment step is performed.

In the vehicle stop determination step, if it is determined that the vehicle is not a stop, the SDPF playback step is performed.

According to the SDPF system and its control method for preventing ammonia odor during reproduction according to the present invention having the above-described structure, it is possible to stop the injection of urea water into the SDPF while maintaining the SDPF at a predetermined temperature before regenerating the SDPF The exhaust of ammonia together with the exhaust gas during the regeneration of the SDPF can be prevented by consuming the ammonia occluded in the SDPF.

Thus, the smell of ammonia is prevented during the regeneration of the SDPF, so that the working environment of the operator becomes comfortable.

1 is a block diagram illustrating an SDPF system in accordance with the prior art;
2 is a flowchart showing a control method of an SDPF system in which ammonia odor is prevented during regeneration according to the present invention.
3 is a block diagram showing an SDPF system in which ammonia odor is prevented during regeneration according to the present invention;
4 is a graph showing the relationship of the amount of ammonia adsorption with temperature in SDPF.
5 is a graph showing the relationship of NOx purification efficiency with temperature in SDPF.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an SDPF system and a control method thereof according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 shows an SDPF system in which ammonia odor is prevented during regeneration according to the present invention.

The engine 11 of the vehicle is connected to an exhaust pipe 12, and exhausts the exhaust gas through the exhaust pipe 12.

The exhaust pipe (12) is provided with various post-treatment devices for reducing the harmful substances contained in the exhaust gas.

For example, a Diesel Oxidation Catalyst (DOC) 12 or an LNT 12 (Lean NOx Trap) may be installed, and an SCP ON DIESEL PARTICULAR FILTER (SDPF) may be installed downstream.

The SDPF 14 is coated with a SCR catalyst material on a DPF (DIESEL PARTICULAR FILTER) that collects soot contained in the exhaust gas, thereby purifying NOx while removing the soot contained in the exhaust gas .

The number of elements stored in the urea water tank 16 is injected through the urea water injector 15 provided at the front end of the SDPF 14 in order to purify NOx from the SDPF 14. [ At this time, the ammonia contained in the urea water injected into the SDPF 14 is discharged to the outside during the regeneration of the SDPF 14,

The SDPF 14 is provided with a temperature sensor 17 capable of measuring the temperature of the SDPF 14. The temperature of the SDPF 14 may be measured by the temperature sensor 17 to maintain the SDPF 14 at a constant temperature during the regeneration of the SDPF 14. [ For example, to regenerate the SDPF 14, it is determined whether the SDPF 14 reaches the ammonia removal temperature set to remove the ammonia stored in the SDPF 14 during the temperature rise of the SDPF 14, 17). The ammonia removal temperature is set to be lower than the regeneration temperature of the SDPF 14.

The SDPF 14 is also provided with an ammonia storage amount sensor 18 for measuring the amount of ammonia stored in the SDPF 14. The amount of ammonia stored in the SDPF 14 while the temperature of the SDPF 14 is raised to a predetermined temperature, that is, the ammonia removing temperature, by using the temperature sensor 17 and the ammonia storage amount sensor 18, To determine whether all the ammonia has been removed from the SDPF 14.

The control unit 20 receives the temperature of the SDPF 14 and the amount of ammonia adsorption from the temperature sensor 17 and the ammonia storage amount sensor 18 and controls the operation of the urea water injector 15. The control unit 20 stops the operation of the urea water injector 15 while the temperature of the SDPF 14 is maintained at the ammonia removal temperature during the regeneration of the SDPF 14, The exhaust gas discharged from the DPFF 14 reacts with ammonia stored in the SDPF 14 to reduce NOx. Since the ammonia is stored in the SDPF 14 by the number of urea injected previously, even if the urea water is not sprayed while the SDPF 14 is maintained at the ammonia removal temperature, And reacts with ammonia occluded in the SDPF 14 to reduce NOx. The control unit 20 controls the urea water injector 15 to inject urea water into the SDPF 14 when the amount of ammonia stored in the SDPF 14 becomes zero according to a value input from the ammonia storage amount sensor 18, ). The reason that the storage amount of ammonia in the SDPF 14 is 0 means that all the ammonia occluded in the SDPF 14 is removed. Therefore, in this state, ammonia is not discharged even if the temperature of the SDPF 14 is regenerated to the regeneration temperature .

Therefore, when the SDPF 14 is reproduced, particularly when the vehicle is stopped, the controller 20 controls the temperature of the SDPF 14 to be raised The operation of the urea water injector 15 is stopped and the supply of urea water is temporarily stopped by the SDPF 14 while the ammonia removal temperature is maintained at the ammonia removal temperature. When the exhaust gas flows into the SDPF 14 while the urea water supply is stopped, the exhaust gas reacts with the ammonia stored in the SDPF 14 to purify the NOx, The stored ammonia is removed. The control unit 20 raises the SDPF 14 to the regeneration temperature and regenerates the SDPF 14 to remove the ammonia stored in the SDPF 14, .

As described above, when the SDPF 14 is regenerated in a stopped state, such as during maintenance in a repair shop, the SDPF 14 is regenerated in a state in which the ammonia occluded in the SDPF 14 is removed, During the regeneration of the SDPF (14), ammonia is discharged from the SDPF (14), so that discomfort due to the smell of ammonia does not occur.

FIG. 3 shows a flowchart of a control method of an SDPF system in which ammonia odor is prevented during regeneration according to the present invention.

A control method of an SDPF system in which ammonia odor is prevented during regeneration according to the present invention includes a temperature rising start step (S110) for starting the temperature of the SDPF (14) to regenerate the SDPF (14) (S130) for determining whether the temperature of the SDPF (14) reaches the ammonia removal temperature set lower than the regeneration temperature of the SDPF (14) (S140) for stopping injection of urea water into the interior of the SDPF (14), an SDPF regeneration step (S160) for regenerating the SDPF (14) while maintaining the SDPF regeneration temperature, .

The temperature rising start step (S110) is a step for starting to raise the temperature of the SDPF (14) in order to regenerate the SDPF (14). If soot is excessively deposited on the SDPF 14 or the efficiency of the SDPF 14 is lowered, the SDPF 14 is raised to the regeneration temperature of the SDPF 14 or higher, The deposited soot is removed and the SDPF 14 is regenerated. Particularly, when the SDPF 14 is excessively deposited, a warning lamp is lit on the instrument panel, and the driver puts the vehicle into the repair shop. In the repair shop, the service regeneration is performed on the SDPF 14 in order to remove the soot accumulated in the SDPF 14.

In the vehicle stop determination step (S120), it is determined whether the vehicle is stopped or not. The ammonia does not stay in the surroundings of the vehicle even if the ammonia is discharged while the vehicle is running, so that it does not cause discomfort due to the smell of ammonia. However, when the vehicle is stopped, as in a repair shop, When the ammonia is discharged from the SDPF 14, the ammonia odor causes an uncomfortable feeling. Therefore, it is preferable that each of the following steps be performed only when it is determined that the vehicle is stopped. Of course, regardless of whether the vehicle is stopped or not, the following steps may be performed.

In step S 130, the temperature of the SDPF 14 at which the temperature increase is started is lowered to the ammonia removal temperature at which the ammonia removal temperature is set to be lower than the regeneration temperature of the SDPF 14 in order to remove the ammonia occluded in the SDPF 14. It is judged whether or not it has arrived.

The ammonia removal temperature may be set to approximately 250 ° C to 300 ° C. The reason why the ammonia removing temperature is set to 250 to 300 deg. C is that the purification rate of NOx is excellent within the temperature range as shown in Fig.

The urea water injection stop step S140 stops the injection of urea water into the SDPF 14 while maintaining the temperature of the SDPF 14 at the ammonia removal temperature. The SDPF 14 injects urea water into the SDPF 14 through the urea water injector 15 provided at the front end of the SDPF 14 if the engine 11 of the vehicle is running, In the water injection stop step S140, the operation of the urea water injector 15 is stopped. When the injection of the urea water is stopped through the urea water injection stop step S140, the ammonia stored in the SDPF 14 and the NOx of the exhaust gas react with each other in the SDPF 14, ) Is consumed. At this time, since the SDPF 14 maintains the ammonia removal temperature which is excellent in the NOx purification rate, the NOx is purified while consuming the ammonia occluded in the SDPF 14.

The ammonia removal completion judgment step (S150) is a step of judging whether all the ammonia occluded in the SDPF 14 has been removed. It is determined whether the ammonia stored in the SDPF 14 is zero by using the ammonia storage amount sensor 18 provided in the SDPF 14 or the like. When the storage amount of ammonia occluded in the SDPF 14 is 0, all the ammonia occluded in the SDPF 14 is consumed. However, if the storage amount of ammonia occluded in the SDPF 14 is greater than 0, the ammonia occluded in the SDPF 14 is not consumed. Therefore, if it is determined that the ammonia occluded in the SDPF 14 has been exhausted in the ammonia removal completion determination step S150, the next step is performed. If it is determined that the ammonia occluded in the SDPF 14 has been exhausted, ) Is repeatedly performed. Since the injection of the urea water through the urea water injector 15 is stopped while the ammonia removal temperature is maintained in the SDPF 14 during the ammonia removal completion determining step S150, .

Meanwhile, the SDPF regeneration step (S160) described later after the urea water injection stop step (S140) may be performed without performing the ammonia removal completion determination step (S150). However, It is preferable to perform the ammonia removal completion judgment step (S150) in order to purify NOx in the SDPF 14 while removing all the ammonia. For example, after stopping the urea water injection stop step (S140) for a predetermined time, the subsequent step may be performed. However, if the subsequent step is carried out in a state where the ammonia occluded in the SDPF 14 is not removed, ammonia is discharged together with the exhaust gas from the SDPF 14 during regeneration of the SDPF 14, . If the urea water injector 15 does not inject urea water into the SDPF 14 despite the ammonia stored in the SDPF 14 is completely removed, NOx is not purified in the SDPF 14 Can be discharged.

Therefore, the ammonia removal completion determination step (S150) is performed to receive the amount of ammonia stored in the SDPF (14), and until the amount of ammonia stored in the SDPF (16) becomes zero, 14 to stop the injection of the urea water, the ammonia occluded in the SDPF 14 is prevented from being lowered and the NOx purification efficiency is prevented from being lowered.

The SDPF regeneration step (S160) raises the SDPF (14) to the regeneration temperature and regenerates the SDPF (14). In the SDPF regeneration step (S160), the SDPF (14) is regenerated by raising the SDPF (14) to 600 占 폚 or more and removing the soot deposited in the SDPF (14).

11: Engine
12: Exhaust pipe
13: DOC, LNT
14: SDPF
15: urea number injector
16: urea water tank
17: Temperature sensor
18: Ammonia storage sensor
20:
S110:
S120: Vehicle stop determination step
S130: Determination of ammonia removal temperature arrival step
S140: Step of stopping injection of the number of elements
S150: Ammonia removal completion judgment step
S160: SDPF reproduction step

Claims (11)

A DPF (DIESEL PARTICULAR FILTER) is provided with an SDPF coated with an SCR (Selective Catalytic Reduction) catalyst material in order to remove soot and nitrogen oxides contained in the exhaust gas exhausted from the engine of the vehicle. In an SDPF system for injecting urea water through an injector,
A temperature sensor installed in the SDPF to measure the temperature of the SDPF,
When the temperature of the SDPF inputted from the temperature sensor reaches the ammonia removing temperature set lower than the regeneration temperature of the SDPF before the SDPF is regenerated, the supply of the urea water to the SDPF is stopped while the SDPF is maintained at the ammonia removing temperature And a control unit for stopping the operation of the urea water injector so that the exhaust gas reacts with the ammonia occluded in the SDPF to remove ammonia in the SDPF and then raising the temperature of the SDPF to regenerate the ammonia. SDPF system is prevented. The method according to claim 1,
Further comprising an ammonia storage amount sensor installed in the SDPF for measuring an amount of stored ammonia stored in the SDPF and outputting the measured amount to the control unit,
Wherein the control unit regenerates the SDPF by raising the temperature of the SDPF to the regeneration temperature of the SDPF when the amount of ammonia is completely removed from the SDPF and the stored amount is zero. The method according to claim 1,
Wherein the ammonia removal temperature is set to 250 to 300 < 0 > C. The method according to claim 1,
If the control unit determines that the vehicle is stationary,
And stops the injection of urea water from the urea water injector while maintaining the SDPF at the ammonia removal temperature. 1. A method for controlling an SDPF system comprising an SDPF for purifying soot and nitrogen oxides contained in exhaust gas discharged from an engine of a vehicle, and a urea water injector for injecting urea water into the SDPF,
A temperature rising start step of starting to raise the temperature of the SDPF to regenerate the SDPF;
Determining whether the temperature of the SDPF reaches an ammonia removal temperature set lower than the regeneration temperature of the SDPF;
A urea water injection stop step of blocking injection of urea water into the SDPF while maintaining the SDPF at the ammonia removal temperature,
And an SDPF regeneration step of regenerating the SDPF by maintaining the SDPF regeneration temperature, wherein ammonia odor is prevented during regeneration. 6. The method of claim 5,
Further comprising an ammonia removal completion judgment step between the step of stopping the injection of urea water and the step of regenerating the SDPF to judge whether or not all the ammonia occluded in the SDPF is removed,
Wherein the step of regenerating the SDPF is performed when it is determined that the ammonia occluded in the SDPF is removed in the step of determining completion of ammonia removal. The method according to claim 6,
In the ammonia removal completion judgment step,
Wherein when the ammonia is not removed, the ammonia removing unit continuously determines whether ammonia has been removed from the SDPF while maintaining the stop of urea water injection by the SDPF. Control method. 6. The method of claim 5,
Wherein the ammonia removal temperature is set to 250 to 300 DEG C in the step of determining the ammonia removal temperature, wherein ammonia odor is prevented during regeneration. 6. The method of claim 5,
And determining whether the temperature of the SDPF has reached the ammonia removal temperature when it is determined that the temperature of the SDPF does not reach the ammonia removal temperature in the step of determining the ammonia removal temperature. A method of controlling an SDPF system that is prevented. 6. The method of claim 5,
Further comprising a vehicle stop determining step of determining whether the vehicle is stopped between the temperature rising start step and the ammonia removing temperature arrival determining step,
Wherein the step of determining ammonia removal temperature is performed when it is determined that the vehicle is stopped in the step of determining the stop of the vehicle, wherein ammonia odor is prevented during regeneration. 11. The method of claim 10,
Wherein the SDPF regeneration step is performed when the vehicle is determined not to be a stop at the vehicle stop determination step.

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