KR20130107015A - Frost diagnostic device for pipe of selective catalytic reduction system and method - Google Patents

Abstract

PURPOSE: A defrosting apparatus of a pipe for a selective catalytic reduction system, and a control method thereof are provided to improve efficiency of a defrosting apparatus by enabling selective defrosting of a specific section when freezing is diagnosed in the specific section based on the freezing diagnosis results. CONSTITUTION: A defrosting apparatus of a pipe for a selective catalytic reduction system comprises piping (50), a dosing valve (41), a reverting valve (42), a cut valve (43), a pump (60), a pressure detecting unit (70), a first bypass line (110), a second bypass line (120), and multiple heaters. The dosing valve is placed in one side of a nozzle (30) in the piping in order to control the discharge of a urea solution. The reverting valve is placed in the piping in order to control the flow of the urea solution in a forward direction or a backward direction. The cut valve is placed in one side of a urea tank (80) in the piping in order to control the suction of the urea solution. The pump is placed in the piping and passes through the reverting valve, thereby forming pressure to pump the urea solution. The pressure detecting unit is placed in the downstream of the reverting valve in the piping in order to detect the pressure of the urea solution. One side of the first bypass line is connected to the upstream of the dosing valve in the piping, and the other side is connected to the urea tank so that the urea solution can be collected in the urea tank by a first valve (112). One side of the second bypass line is connected to the upstream of the reverting valve in the piping, and the other side is connected to the urea tank so that the urea solution can be collected in the urea tank by a second valve (122). The heater heats a selected section in the piping depending on the opening or closing state of the first and the second bypass lines.

Description

Defrosting device for pipes for selective reduction catalyst system and its control method {Frost diagnostic device for pipe of Selective Catalytic Reduction System and method}

The present invention relates to a defrosting apparatus for a pipe for a selective reduction catalyst system and a control method thereof, and more particularly, to purifying nitrogen oxides (NOx) contained in exhaust gas of a diesel engine using urea liquid. The present invention relates to a thawing apparatus for a pipe for a selective reduction catalyst system capable of diagnosing freezing of phosphorus pipe and a control method thereof.

In general, the exhaust gas of a diesel engine contains nitrogen oxides (NOx), and these nitrogen oxides (NOx) must be purified because they cause air pollution. As a device for purifying nitrogen oxides, a selective catalytic reduction (SCR) system is known as "SCR".

The SCR system sprays urea liquid upstream of the exhaust gas so that nitrogen oxides are reduced and purified from the SCR catalyst.

By the way, the urea liquid freezing occurs at about minus 10 degrees Celsius, and the freezing causes clogging or narrowing of the pipe. As such, if the pipeline is blocked or narrowed, the urea solution cannot be provided normally.

As a technique proposed to solve the above problems, the pipe is diagnosed whether the frost (frosting), and if it is determined that the frozen state is driven by the heater to operate the SCR system after thawing. This will be described in more detail with reference to FIG. 1.

In the SCR system, an optional reduction catalyst 20 (SCR) is provided in the exhaust pipe 10, and a nozzle 30 is disposed upstream of the selective reduction catalyst 20 so that the urea liquid is injected into the exhaust gas.

The urea liquid is contained in the urea tank 80, is a pipe 50 from the urea tank 80 to the nozzle 30, and the urea liquid is pumped by the pump 60.

The pipe 50 is provided with a dosing valve 41 adjacent to the nozzle 30, and the urea liquid is injected or stopped by the nozzle 30 depending on whether the dosing valve 41 is opened or closed.

In addition, a reversing valve 42 is provided in a section connected to the pump 60 in the pipe 50, and the flow direction of the urea liquid is switched in the forward or reverse direction according to the operation of the reversing valve 42.

In addition, the pipe 50 is provided with a cut valve 43 on the side adjacent to the urea tank 80, the urea liquid is sucked or sucked out from the urea tank 80 depending on whether the cut valve 43 is opened or closed.

On the other hand, in the state in which the dosing valve 41 and the cut valve 43 are closed, the pressure is maintained in the urea liquid in the pipe 50, for example, about 6 bar to about 10 bar, and when either valve is opened, Urea liquid can be pushed out by pressure and discharged.

In addition, a pressure detection unit 70 is disposed in the pipe 50 on the downstream side of the reversing valve 42. The pressure detection unit 70 detects the pressure of the urea liquid in the pipe 50 and provides the detection value to the controller.

The conventional SCR system configured as described above opens the dosing valve 41 to inject urea liquid through the nozzle 30, measures the time it takes for the pressure to decrease and compares it with a threshold already set. As a result, determine whether the time required for pressure drop is delayed or accelerated.

If the time required for the pressure drop to decrease the pressure of urea proceeds quickly, it is determined to be normal and operate the SCR system normally.

However, if the time required for the pressure drop to decrease the pressure of the urea liquid is delayed or the pressure drop is slow, it is determined that the urea liquid is frozen and the pipe is narrowed somewhere in the pipe 50, and it is judged as the freezing of the pipe 50, and the thawing apparatus Run the SCR system after thawing the heater.

However, in the conventional SCR system as described above, the technique for thawing the freezing of the pipe has the following problems.

The urea solution is sprayed for a predetermined time, for example, for about 1 to 3 seconds to determine the degree of pressure drop to diagnose the freezing. At this time, there is a possibility of air pollution by the injected urea solution.

In addition, since it is not possible to determine which section of the pipe 50 is frozen, there is a problem in that the heater of the thawing apparatus is operated in the entire section of the pipe 50 when the pipe is diagnosed as freezing.

That is, in the conventional SCR system, a device for diagnosing and thawing a pipe freeze has a problem that the reliability of the diagnosis result is low when the freeze state or the thaw state is diagnosed, and thus the efficiency of the thaw device is low.

Japanese Patent Laid-Open No. 2012-2062 (2012.01.05.)

Therefore, the technical problem to be achieved by the present invention is to defrost the pipes for the selective reduction catalyst system and to determine whether the freeze for each section to improve the reliability of the diagnostic results by the thawing apparatus and control of the pipe for the selective reduction catalyst system The purpose is to provide a method.

Another object of the present invention is to provide a selective reduction catalyst piping for improving the efficiency of the thawing apparatus by selectively thawing a desired specific section when diagnosed as freezing in a particular section based on the freezing diagnosis result. It is an object of the present invention to provide a thawing apparatus and a control method thereof.

Another object of the present invention is to recover the urea fluid flowing during the diagnosis of pipe freezing to recycle the urea, and to prevent the end of the urea is discharged unauthorized to reduce the environmental pollution selective It is an object of the present invention to provide a defrosting apparatus for a pipe for a reduction catalyst system and a control method thereof.

The present invention has been made in view of the above problems, and it is an object of the present invention to at least partially solve the problems in the conventional arts. There will be.

Defrosting apparatus of the piping for the selective reduction catalyst system according to the present invention for achieving the above technical problem, the pipe 50 is piped from the urea tank 80 to the nozzle 30 is conveyed urea liquid; A dosing valve 41 disposed at one side of the nozzle 30 in the pipe 50 to control discharge of the urea liquid; A reversing valve 42 disposed on the pipe 50 to control the flow direction of the urea liquid in a forward or reverse direction; A cut valve 43 disposed at one side of the urea tank 80 in the pipe 50 to control suction of the urea liquid; A pump (60) disposed on the pipe (50) to form a pressure to pressurize the urea liquid via the reversing valve (42); A pressure detecting unit (70) disposed downstream of the reversing valve (42) on the pipe (50) to detect the pressure of the urea liquid; One side is connected to the upstream side of the dosing valve 41 on the pipe 50 and the other side is connected to the urea tank 80 so that the urea liquid is controlled by the first valve 112. The first bypass line 110 withdrawn); One side is connected to the upstream side of the reversing valve 42 on the pipe 50 and the other side is connected to the urea tank 80 so that the urea liquid is controlled by the second valve 122. A second bypass line 120 withdrawn to 80; And a plurality of heaters in which a section selected from the pipe 50 is heated according to whether the first and second bypass lines 110 and 120 are opened or closed.

In addition, the defrosting apparatus of the piping for the selective reduction catalyst system according to the present invention is detected by the pressure detection unit 70 when the first valve 112 is opened while the second valve 122 is closed. If the time required to reach the set pressure value is delayed than the set time, the pipe 50 between the dosing valve 41 and the reversing valve 42 may be heated.

In addition, the defrosting apparatus of the piping for the selective reduction catalyst system according to the present invention is detected by the pressure detection unit 70 when the second valve 122 is opened while the first valve 122 is closed. When the time required for the pressure value to reach the set pressure value is delayed than the set time, the pipe 50 of the path circulating the pump 60 in the reversing valve 42 may be heated.

In addition, the defrosting apparatus of the piping for the selective reduction catalyst system according to the present invention, the pressure detected by the pressure detection unit 70 when the first valve 112 is opened in a state in which the second valve 122 is closed. When the time required for the value to reach the set pressure value is equal to or faster than the set time, and the second valve 122 is opened while the first valve 112 is closed, the pressure detecting unit 70 If the pressure value detected in the time taken to reach the set pressure value is faster or equal to the set time, the pipe 50 between the reversing valve 42 and the cut valve 43 may be heated. have.

In addition, the thawing apparatus of the piping for the selective reduction catalyst system according to the present invention is disposed downstream of the first bypass line 110 and the second bypass line 120, the first bypass line 110 Or urea recovery tank 130 in which the stored urea liquid is provided to the urea tank 80 after storing the recovered urea liquid when the urea liquid is recovered through the second bypass line 120. Can be.

Moreover, the control method of the thawing apparatus of the piping for selective reduction catalyst systems which concerns on this invention in order to achieve the said technical subject, the desired pressure value in the pressure detection unit 70 arrange | positioned downstream of the reversing valve 42 is carried out. Determining whether the time required for the detection is shorter than the first threshold value, and if the time is short, proceeds to the end step (s10); A first performing step (s20) of opening the first valve (112) when the required time for the pressure drop of the pressure value is longer than a first threshold value in the first determining step (s10); A second determination step (s30) of determining whether a required time for the pressure drop of the pressure value is shorter than a second threshold value after the first valve 112 is opened in the first performing step (s20); In the second determination step (s30), if the time required for the pressure drop of the pressure value is longer than the second threshold value, the first heater is turned on so that the pipe 50 between the dosing valve 41 and the reversing valve 42 is heated. A second performing step s40 returning to the first determining step s10; A third performing step (s50) of opening the second valve (122) when the required time for the pressure drop of the pressure value is shorter than a second threshold value in the second determining step (s30); A third determination step (s60) of determining whether a time required for the pressure drop of the pressure value is shorter than a third threshold value after the second valve 122 is opened in the third performing step (s50); In the third determination step (s60), if the time required for the pressure drop of the pressure value is longer than a third threshold value, the second pipe may be heated such that the pipe 50 of the path circulating the pump 60 is heated by the reversing valve 42. A fourth performing step s70 of turning on a heater and returning to the first determining step s10; And a third heater such that the pipe 50 between the reversing valve 42 and the cut valve 43 is heated when the required time for the pressure drop of the pressure value is shorter than a third threshold value in the third determination step s60. It includes; and a fifth performing step (s80) proceeds to the end step.

In addition, the method for controlling the thawing apparatus of the pipe for the selective reduction catalyst system according to the present invention, when performing the second performing step (s40), closes the first valve 112, the third performing step (s50) The first valve 112 is closed when the step S1) is performed, and the second valve 122 is closed when the fourth step S70 is performed, and the fifth step S80 is performed. At this time, the second valve 122 may be closed.

In addition, according to the present invention, a control method of a defrosting apparatus for a pipe for a selective reduction catalyst system may include driving a motor 60 to increase a pressure in the pipe 50 after the fifth performing step s80. (s90); After the sixth performing step s80, it is determined whether the time required for the pressure detecting unit 70 to detect a desired pressure value is shorter than a first threshold value, and if it is short, a fourth determination step of proceeding to an end step ( s100); And a seventh performing step (s110) of displaying an error if it is determined that the time required for detecting the desired pressure value in the pressure detecting unit (70) is longer than a first threshold value in the fourth determining step (s100). It may further include.

The details of other embodiments are included in the detailed description and drawings.

The defrosting apparatus and the control method of the pipe for the selective reduction catalyst system according to the present invention made as described above, it is possible to improve the reliability of the diagnostic results by distinguishing the pipe by section and whether or not to freeze by each section.

In addition, the apparatus for thawing a pipe for a selective reduction catalyst system and a control method thereof according to the present invention can selectively thaw a specific pipe section desired when it is diagnosed as freezing in a specific pipe section based on the freezing diagnosis result. The efficiency of the thawing apparatus can be improved.

In addition, the apparatus for thawing a pipe for a selective reduction catalyst system and a control method thereof according to the present invention can recover the urea fluid flowing during the diagnosis of pipe freezing, and recycle the urea liquid, and the urea liquid is discharged without permission. It can contribute to reducing air pollution by preventing closure.

1 is a view for explaining a conventional selective reduction catalyst system.
2 is a view for explaining a thawing apparatus of a pipe for a selective reduction catalyst system according to an embodiment of the present invention.
3 is a flowchart illustrating a control method of a thawing apparatus of a pipe for a selective reduction catalyst system according to an exemplary embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and how to accomplish them, will become apparent by reference to the embodiments described in detail below with reference to the accompanying drawings.

Like reference numerals refer to like elements throughout the specification, and like elements to those of the prior art are denoted by the same reference numerals, and a detailed description thereof will be omitted.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.

Hereinafter, a defrosting apparatus for a pipe for a selective reduction catalyst system and a control method thereof according to an embodiment of the present invention will be described with reference to FIGS. 2 and 3.

2 is a view for explaining a thawing apparatus of a pipe for a selective reduction catalyst system according to an embodiment of the present invention. Accompanying drawings, Figure 3 is a flow chart for explaining a control method of the thawing apparatus of the pipe for the selective reduction catalyst system according to an embodiment of the present invention.

In the thawing apparatus of the pipe for the selective reduction catalyst system according to an embodiment of the present invention, the pipe 50 is divided into first, second, and third pipes 51, 52, and 53 for each section.

More specifically, the first pipe 51 is a section from the dosing valve 41 to the reversing valve 42, and the second pipe 52 is the levering valve 42 via the pump 60. The third pipe 53 is a section of the cut valve 43 branches from the reversing valve 42.

Meanwhile, the defrosting apparatus uses a heater, and a plurality of heaters are provided, and more specifically, each of the first, second, and third pipes 51, 52, and 53 for each section in the pipe 50 described above. It may be a heater that is independently powered and generates heat.

In other words, when you want to heat a certain section is to operate the heater of the corresponding team, thereby can be used to defrost the pipe of the particular section.

On the other hand, the first bypass line 110 is provided to connect the first pipe 51 and the urea tank 80. The first bypass line 110 is provided with a first valve 112, and the urea liquid present in the first pipe 51 to the urea tank 80 under the control of whether the first valve 112 is opened or closed. Can be recovered.

In more detail the connection configuration of the first bypass line 110, one side is connected to the upstream side of the dosing valve 41 on the pipe 50 and the other side is connected to the urea tank (80).

In addition, as the first valve 112 is disposed at a position closer to the first pipe 51, the reliability of the operation of the thawing apparatus may be further improved. The reason is that when the first pipe 51 is frozen, the section between the first pipe 51 and the first valve 112 may be frozen on the first bypass line 110, and the freezing section is minimized. For this purpose, the first valve 112 may be disposed close to the first pipe 51. More specifically, the first valve 112 may be provided at the T-shaped pipe portion to which the first pipe 51 and the first bypass line 110 are connected.

On the other hand, the second bypass line 120 is provided to connect the third pipe 53 and the urea tank 80. The second bypass line 120 is provided with a second valve 122, and the urea liquid present in the third pipe 53 is transferred to the urea tank 80 under the control of whether the second valve 122 is opened or closed. Can be recovered.

In more detail the connection configuration of the second bypass line 120, one side is connected to the upstream side of the reversing valve 42 on the pipe 50 and the other side is connected to the urea tank (80).

In addition, as the second valve 122 is disposed at a position closer to the third pipe 53, the reliability of the operation of the thawing apparatus may be further improved. The reason for this is the same as the reason for arranging the first valve 112, and thus redundant description is omitted.

On the other hand, the urea recovery tank 130 may be further provided downstream of the first bypass line 110 and the second bypass line 120. When the urea is recovered through the first bypass line 110 or the second bypass line 120, the urea recovery tank 130 may store the recovered urea and then store the urea in the urea tank 80. Can be.

In addition, the urea recovery tank 130 may be used as a temporary storage as described above, which is a large difference between the pressure in the urea tank 80 and the pressure in the first and second bypass lines 110 and 120. When circumstance or an unexpected situation such as the start of the diesel engine is turned off may not be smoothly recovered, the urea recovery tank 130 may be provided to stabilize the recovery of the urea.

With reference to the accompanying drawings 2 and 3 will be described the operation and control method of the thawing apparatus of the pipe for the selective reduction catalyst system according to an embodiment of the present invention.

In a general situation, when nitrogen oxide (NOx) is detected in the exhaust pipe 10, the SCR system is driven so that the urea liquid is injected through the nozzle 30. That is, urea liquid is mixed with the exhaust gas, and nitrogen oxide and urea liquid are reduced and purified by chemical reaction.

That is, when the urea liquid is injected, the dosing valve 41 and the cut valve 43 are switched to the open state, the reversing valve 42 maintains the forward direction, and the pump 60 is driven to pump the urea liquid. Done.

On the other hand, when the urea liquid is not injected, the dosing valve 41 and the cut valve 43 are switched to the closed state. At this time, the urea liquid is present in the pipe 50, the start of the diesel engine is turned on, and the pump ( The pressure of the urea liquid may be increased from the moment when 60 is driven to the predetermined predetermined pressure. The predetermined pressure may vary from 5 bar to 10 bar, for example, and may be set in consideration of external factors such as the specification of the SCR system or the length of the pipe.

When the reversing valve 42 is switched in the reverse direction, the urea liquid present in the pipe 50 is pumped toward the urea tank 80 and recovered.

When the temperature drops to about 10 degrees Celsius, the urea can be frozen, so whether the freezing is diagnosed by the pipe 50 is operating normally, the SCR system is operated as usual.

The present invention is to diagnose which section in the pipe 50 is frozen, which will be described with reference to the accompanying drawings, FIG.

When the diesel engine is turned on and the diagnosis of pipe freezing is started, the motor 60 is driven to raise the pressure in the pipe 50 until a desired pressure value is detected. The pressure value is detected by the pressure detection unit 70, and it is determined whether or not it is short by comparing the time required to rise to a desired pressure value in a general pressure state with a first threshold value, which is the first determination step s10. to be.

In the first determination step s10, it is determined whether the time required to detect the desired pressure value is shorter than the first threshold value, and if it is short, it goes to the end step, and if it is long, it goes to the next step.

The desired pressure value may for example be 9 bar, which may be set differently depending on the specifications of the SCR system. In addition, the first threshold value may be a time value required until the desired pressure in a general situation in which the pipe 50 is not frozen.

On the other hand, the first, second, third, threshold value to be described later may be set within a range of seconds, for example, to set the value of the comparison target, more specifically, may be within 3 seconds, SCR It can be set differently depending on the specifications of the system or the working environment.

That is, in a general situation in which the pipe 50 is not frozen, the time required to reach a desired pressure value may be short or similar. This is diagnosed as a normal state, and the SCR system is operated in a normal operating state. Diagnosis is to end.

On the contrary, when the pipe 50 is frozen and there is a problem, the time required for reaching the desired pressure is delayed, and this is delayed to thaw the pipe 50 by determining that the pipe 50 is frozen. It will drive the heater of the device.

In the above-described first determination step (s10), the time required for the pressure drop to check the pressure drop is checked, and if the time required for the pressure drop is longer than the first threshold value, the first valve 112 is opened to supply the urea liquid pressure in the pipe 50. Proceed with the first performing step (S20) to induce the fall of.

When the first valve 112 is opened, the urea liquid present in the first pipe 51 is recovered through the first bypass line 110, and a pressure drop is performed for a predetermined time.

After the first valve 112 is opened, the process proceeds to a second determination step s30 of determining whether the required time for the pressure drop of the pressure value is shorter than the second threshold value.

In the second determination step s30, when the time required for the pressure drop of the pressure value is longer than the second threshold value, the first heater is turned on so that the pipe 50 between the dosing valve 41 and the reversing valve 42 is heated, and the above-described method is used. The second performing step s40 returns to the first determination step s10.

Especially. If the first pipe 51 is frozen, the time required for the pressure drop will be delayed or longer when the first valve 112 is opened. In this case, the first pipe 51 is the basis for determining that the first pipe 51 is frozen. At this time, it is irrelevant whether the second valve 122 is opened or closed.

Meanwhile, in the second performing step s40, the first valve 112 may be closed. This prevents the pressure drop by the first valve 112 in the process that follows.

In the second determination step s30, when the required time for the pressure drop of the pressure value is shorter than the second threshold value, the third performing step s50 of opening the second valve 122 is performed.

In addition, the first valve 112 may be closed in the third performing step s50. This prevents the pressure drop by the first valve 112 in the process that follows.

After the second valve 122 is opened in the third performing step s50, the process proceeds to a third determining step s50 for determining whether the required time for the pressure drop of the pressure value is shorter than the third threshold value.

In the third determination step s60, when the time required for the pressure drop of the pressure value is longer than the third threshold value, the second heater is turned on so that the pipe 50 of the path circulating the pump 60 is heated by the reversing valve 42. A fourth performing step s70 of returning to the first determination step s10 is performed.

In addition, the second valve 122 may be closed in the fourth performing step s70. This prevents the pressure drop by the second valve 122 in the subsequent process.

In this case, when the second pipe 52 is frozen and the pipe is narrowed or blocked, the time required for the pressure drop will be long and slow, which is the basis for judging that the second pipe 52 is frozen.

When the freezing situation of the second pipe 52 is explained in detail, when the time required for pressure drop is short when the first valve 112 is opened, when the time required for pressure drop is long when the second valve 122 is opened. to be.

That is, when the second pipe 52 is diagnosed as freezing in the third determination step s60, the second heater is turned on so that the pipe 50 of the path circulating between the reversing valve 42 and the pump 60 is heated. .

On the other hand, when the time required for the pressure drop of the pressure value is shorter than the third threshold value in the third determination step s60, the third heater is turned on so that the pipe 50 between the reversing valve 42 and the cut valve 43 is heated. A fifth performing step s80 proceeds to an end step.

In this case, when the third pipe 53 is frozen and the pipe is narrowed or blocked, the time required for the pressure drop will be short, which is the basis for judging that the third pipe 53 is frozen.

When the freezing situation of the third pipe 53 is explained in detail, when the time required for pressure drop is short when the first valve 112 is opened, when the time required for pressure drop is short when the second valve 122 is opened. to be.

That is, when it is diagnosed that the third pipe 53 is frozen in the third determination step s60, the third heater is turned on to terminate the pipe 50 between the reversing valve 42 and the cut valve 43. This is to perform the fifth performing step (s80).

In addition, the second valve 122 may be closed in the fifth performing step s80. This prevents the pressure drop by the second valve 122 in the subsequent process.

On the other hand, after the above-described fifth performing step (s80) may be further added to the subsequent step of increasing the pressure in the pipe 50 to diagnose whether or not normal.

More specifically, after the fifth performing step s80, a sixth performing step s90 of driving the motor 60 to increase the pressure in the pipe 50 is performed.

After the sixth performing step (s80), it is determined whether the time required for the pressure detecting unit 70 to detect a desired pressure value is shorter than the first threshold value, and if it is short, the fourth determining step (s100) proceeds to the end step. Perform

That is, when the pressure rises quickly inside the pipe 50 in the state in which the first and second valves 112 and 122 are closed, the pipe 50 is diagnosed as a normal state in which the pipe 50 is not blocked or narrowed and ends.

On the other hand, if it is determined in the fourth determination step s100 that the time required for detecting the desired pressure value in the pressure detection unit 70 is longer than the first threshold value, the seventh performing step s110 of displaying an error is performed. .

That is, even if the first, second, and third heaters are turned on to increase the temperature in the entire pipe 50, if the rising rate of the pressure is delayed, it is not a problem to diagnose whether it is frozen. It will display an error and exit.

On the other hand, in the above-described first, second, third, and fourth determination step (s10, s30, s60, s100), the short time required for the pressure to rise or fall is secured in the pipe 50. It is recognized that the urea solution can be injected normally.

On the other hand, in the first, second, third, and fourth determination step (s10, s30, s60, s100), the long time it takes for the pressure to rise or fall is that the pipe 50 is frozen and the pipeline is frozen. If it is narrowed or blocked, it is judged abnormal.

On the other hand, due to the opening of the first and second valves 112 and 122, the urea liquid in the pipe 50 is recovered to the urea tank 80 or the urea recovery tank 130, and the urea recovery tank 130 If recovered at first may later be delivered back to the urea tank (80).

As described above, the apparatus for thawing a pipe for a selective reduction catalyst system and a control method thereof according to an embodiment of the present invention distinguish the pipe 50 by sections (first and second third pipes) and freeze each section. By being able to diagnose whether or not it is possible to improve the reliability of the diagnosis results.

In addition, the apparatus for thawing a pipe for a selective reduction catalyst system and a control method thereof according to an embodiment of the present invention selectively thaw a desired specific pipe section when a freeze is diagnosed in a specific pipe section based on a freeze diagnosis result. This can improve the efficiency of the thawing apparatus.

In addition, the apparatus for thawing a pipe for a selective reduction catalyst system and a control method thereof according to the present invention can recover the urea fluid flowing during the diagnosis of pipe freezing, and recycle the urea liquid, and the urea liquid is discharged without permission. It can contribute to reducing air pollution by preventing closure.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. will be.

Therefore, it should be understood that the above-described embodiments are to be considered in all respects as illustrative and not restrictive, and the scope of the present invention is indicated by the appended claims. The scope of the claims and their equivalents It is to be understood that all changes or modifications that come within the meaning and range of equivalency of the claims are to be embraced within their scope.

The thawing apparatus and method for controlling the pipe for the selective reduction catalyst system according to the present invention can be used to selectively heat the pipe having a problem in the pipe in the pipe.

10: exhaust pipe
20: Selective Catalytic Reduction (SCR)
30: nozzle
41: dosing valve
42: reversing valve
43: cut valve
50: piping
51, 52, 53: first, second, third pipe
60: pump
70: pressure detection unit
80: urea tank
110, 120: first and second bypass lines
112, 122: first and second valves
130: urea recovery tank

Claims (8)

A pipe 50 piped from the urea tank 80 to the nozzle 30 to which urea liquid is transferred;
A dosing valve 41 disposed at one side of the nozzle 30 in the pipe 50 to control discharge of the urea liquid;
A reversing valve 42 disposed on the pipe 50 to control the flow direction of the urea liquid in a forward or reverse direction;
A cut valve 43 disposed at one side of the urea tank 80 in the pipe 50 to control suction of the urea liquid;
A pump (60) disposed on the pipe (50) to form a pressure to pressurize the urea liquid via the reversing valve (42);
A pressure detecting unit (70) disposed downstream of the reversing valve (42) on the pipe (50) to detect the pressure of the urea liquid;
One side is connected to the upstream side of the dosing valve 41 on the pipe 50 and the other side is connected to the urea tank 80 so that the urea liquid is controlled by the first valve 112. The first bypass line 110 withdrawn);
One side is connected to the upstream side of the reversing valve 42 on the pipe 50 and the other side is connected to the urea tank 80 so that the urea liquid is controlled by the second valve 122. A second bypass line 120 withdrawn to 80; And
A plurality of heaters in which a section selected from the pipe 50 is heated according to whether the first and second bypass lines 110 and 120 are opened or closed;
Defrosting device for piping for the selective reduction catalyst system comprising a.
The method of claim 1,
When the first valve 112 is opened while the second valve 122 is closed, the time required for the pressure value detected by the pressure detecting unit 70 to reach the set pressure value is set. If you delay more than time,
Defrosting device for a selective reduction catalyst system, characterized in that the piping (50) between the dosing valve (41) and the reversing valve (42) is heated.
The method of claim 1,
The time for setting the time required for the pressure value detected by the pressure detecting unit 70 to reach the set pressure value when the second valve 122 is opened while the first valve 122 is closed. If it is delayed,
Defrosting device for a selective reduction catalyst system, characterized in that the piping 50 of the path circulating the pump 60 in the reversing valve 42 is heated.
The method of claim 1,
When the first valve 112 is opened while the second valve 122 is closed, the time required for the pressure value detected by the pressure detecting unit 70 to reach the set pressure value is greater than the set time. Fast or equal, and the time required for the pressure value detected by the pressure detecting unit 70 to reach the set pressure value when the second valve 122 is opened while the first valve 112 is closed. Is earlier than or equal to the set time,
Defrosting device of the piping for the selective reduction catalyst system, characterized in that the piping (50) between the reversing valve (42) and the cut valve (43) is heated.
The method of claim 1,
The urea solution is disposed downstream of the first bypass line 110 and the second bypass line 120, and the urea liquid is recovered through the first bypass line 110 or the second bypass line 120. The urea recovery tank 130 in which the stored urea liquid is provided to the urea tank 80 after storing the recovered urea liquid;
Defrosting device of the piping for the selective reduction catalyst system further comprising.
In the pressure detecting unit 70 disposed downstream of the reversing valve 42, it is determined whether the time required for detecting the desired pressure value is shorter than the first threshold value. s10);
A first performing step (s20) of opening the first valve (112) when the required time for the pressure drop of the pressure value is longer than a first threshold value in the first determining step (s10);
A second determination step (s30) of determining whether a required time for the pressure drop of the pressure value is shorter than a second threshold value after the first valve 112 is opened in the first performing step (s20);
In the second determination step (s30), if the time required for the pressure drop of the pressure value is longer than the second threshold value, the first heater is turned on so that the pipe 50 between the dosing valve 41 and the reversing valve 42 is heated. A second performing step s40 returning to the first determining step s10;
A third performing step (s50) of opening the second valve (122) when the required time for the pressure drop of the pressure value is shorter than a second threshold value in the second determining step (s30);
A third determination step (s60) of determining whether a time required for the pressure drop of the pressure value is shorter than a third threshold value after the second valve 122 is opened in the third performing step (s50);
In the third determination step (s60), if the time required for the pressure drop of the pressure value is longer than a third threshold value, the second pipe may be heated such that the pipe 50 of the path circulating the pump 60 is heated by the reversing valve 42. A fourth performing step s70 of turning on a heater and returning to the first determining step s10; And
In the third determination step (s60), if the time required for the pressure drop of the pressure value is shorter than the third threshold value, the third heater is heated such that the pipe 50 between the reversing valve 42 and the cut valve 43 is heated. A fifth performing step s80 which is turned on and proceeds to an end step;
Method for controlling the thawing apparatus of the piping for the selective reduction catalyst system comprising a.
The method according to claim 6,
When the second performing step (s40) is performed, the first valve 112 is closed,
When the third performing step (s50) is performed, the first valve 112 is closed,
When performing the fourth performing step (s70), the second valve 122 is closed,
Closing the second valve 122 when performing the fifth performing step (s80).
Method for controlling the thawing apparatus of the piping for the selective reduction catalyst system, characterized in that.
The method according to claim 6,
A seventh performing step (s90) of increasing the pressure in the pipe (50) by driving the motor (60) after the fifth performing step (s80);
After the sixth performing step s80, it is determined whether the time required for the pressure detecting unit 70 to detect a desired pressure value is shorter than a first threshold value, and if it is short, a fourth determination step of proceeding to an end step ( s100); And
A seventh performing step (s110) of displaying an error if it is determined that the time required for detecting the desired pressure value by the pressure detecting unit (70) is longer than a first threshold value in the fourth determining step (s100);
Method for controlling the thawing apparatus of the piping for the selective reduction catalyst system further comprising.

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