KR20150062674A - Apparatus and Method for Urea Injection Control in Selective Catalytic Reduction System - Google Patents

Abstract

The present invention relates to an apparatus and a method for urea injection control in a selective catalytic reduction (SCR) system. According to the present invention, an apparatus for urea injection control in the SCR system comprises: a distribution module pumping urea authorized as an aqueous solution from a tank in accordance with a control of a control module to be pressurized and authorized to an input module; an input module controlling an amount of inputted urea authorized to an injector in accordance with the control of the control module; and the control module controlling the input module.

Description

Technical Field [0001] The present invention relates to an apparatus and a method for controlling urea supply in an SCR system,

The present invention relates to an SCR (Selective Catalytic Reduction System) system for processing exhaust gas discharged from a diesel engine installed in a ship or the like. In particular, in an SCR system, a Urea is introduced into an exhaust gas flowing into a reactor, In the case of removing the nitrogen oxide of the gas, the amount of the nitrogen oxide which is untreated and discharged from the reactor on the basis of the amount of urea injected into the exhaust gas is predicted, and the amount of the injected urea is determined on the basis of the amount of discharged nitrogen oxide, The urea supply control device of the SCR system for efficiently removing the nitrogen oxide by adjusting the amount of the input urea without installing a sensor for detecting the amount of nitrogen oxide in the exhaust gas outlet of the reactor, And methods.

Nitrogen oxides and sulfur oxides among exhaust gases emitted from diesel engines commonly used in ships are representative air pollutants subject to emission regulation from the International Maritime Organization (IMO), which is a member of the United Nations (UN).

Nitrogen oxides refer to NO, NO2, NO3, N2O, N2O3, N2O4 and N2O5, but most nitrogen oxides are NO and NO2. Sulfur oxides are mainly SO2 in which sulfur components contained in fuels such as coal and petroleum are oxidized in the combustion process.

Nitrogen oxides are generated by the reaction of Nitrogen in the combustion process with thermal NOx generated by the reaction of nitrogen and oxygen in the air in the high temperature region, Prompt NOx generated by the reaction of hydrocarbons generated from the fuel with nitrogen in the air, Fueled NOx.

SCR systems have been used to remove nitrogen oxides generated by the combustion reaction of fossil fuels. In the SCR system, as shown in Equations (1) and (2), the nitrogen oxide of the exhaust gas is converted into nitrogen and water by a catalyst provided in the reactor and removed by injecting urea into the exhaust gas flowing into the reactor .

4NO + 4NH3 + O2 - > 4N2 + 6H2O (Formula 1)

6NO2 + 8NH3 - > 7N2 + 12H2O (Formula 2)

In the conventional SCR system, when the urea is injected into the exhaust gas flowing into the reactor, the urea in the form of an aqueous solution stored in the tank is atomized by the urea supply device, and the predetermined amount is continuously injected.

Such a urea supply apparatus atomizes urea in the form of an aqueous solution stored in a tank and continuously injects urea into the exhaust gas flowing into the reactor, thereby causing the reactor to remove nitrogen oxides of the exhaust gas by using urea. In order to efficiently remove nitrogen oxides, it is necessary to grasp the amount of nitrogen oxides untreated and discharged from the reactor, and to inject the corresponding amount of urea into the exhaust gas.

However, in order to determine the amount of nitrogen oxides discharged from the reactor, a sensor for detecting the amount of nitrogen oxides in the gas outlet of the reactor must be separately installed and operated. Therefore, the cost of the SCR system is increased, There is a problem that it is disadvantageous to remuneration.

DISCLOSURE Technical Problem The present invention has been proposed in order to solve the conventional problems as described above. In the SCR system, when the urea is introduced into the exhaust gas flowing into the reactor and the nitrogen oxide of the exhaust gas is removed by the reactor, The amount of the injected urea is determined based on the amount of the discharged urea based on the amount of the discharged nitrogen oxide and the amount of the injected urea determined by reflecting the engine load, And an object of the present invention is to provide an apparatus and method for controlling the supply of urea in an SCR system in which nitrogen oxides are efficiently removed by adjusting the amount of charged urea even without providing a sensor for detecting the amount of nitrogen oxides at the discharge port.

In order to achieve the above object, there is provided an apparatus for regulating the supply of urea in an SCR system, comprising: a distribution module for pumping and pressurizing urea applied in the form of an aqueous solution from a tank under the control of a control module, The urea supplied from the distribution module is applied to the injector together with the compressed air to atomize the urea by the injector and to inject the urea into the exhaust gas flowing into the reactor, An injection module for controlling the amount of injected urea applied to the injector according to the control; And controlling the distribution module and the input module so as to inject urea into the exhaust gas flowing into the reactor. The amount of the charged urea is detected on the basis of the input urea amount detection signal applied from the input module, The amount of nitrogen oxides discharged from the engine is determined based on the estimated amount of nitrogen oxides, the amount of urea to be injected is determined in accordance with the engine load, Module.

According to the urea supply control device of the SCR system according to the present invention, the distribution module includes: a pump for pumping and pressurizing the urea applied from the tank according to the control of the control module to apply to the injection module; And a plurality of valves for manually opening and closing the urea supply system via the pump.

According to the urea supply control device of the SCR system according to the present invention, the charging module includes a control valve for controlling an amount of urea applied to the injector from the distribution module under the control of the control module; A flow meter for detecting an amount of the input urea applied to the injector from the control valve and for applying an input urea amount detection signal to the control module; A plurality of valves for manually opening and closing the urea supply system via the control valve and the flow meter; And a plurality of valves for manually opening and closing the supply system of compressed air applied to the injector.

According to another aspect of the present invention, there is provided an urea supply control apparatus for an urea supply control system, wherein the control module controls the supply module and the supply module to supply urea, A microcomputer for performing a process; A memory for storing the urea supply control program and providing the microcontroller with the urea supply control program according to the control of the microcomputer; A display unit for displaying various data generated in the urea supply adjusting process under the control of the microcomputer; An operation unit for inputting various data and commands for controlling the urea supply by manual operation to the microcomputer; A first matching unit for matching a control signal applied from the microcomputer so as to be usable in the distribution module; A second matching unit for matching a control signal applied from the microcomputer so as to be usable in the input module; A third matching unit for matching the input urea amount detection signal applied from the input module so that the input urea amount detection signal can be processed by the microcomputer; And a fourth matching section for matching the engine load signal applied from the engine so as to be processable by the microcomputer.

In addition, according to the present invention, the microcomputer calculates the amount of the applied urea based on the detection signal applied through the third matching unit from the input module, The amount of urea to be injected is determined based on the predicted amount of nitrogen oxides and the amount of urea to be injected is determined in accordance with the engine load according to the engine load signal applied through the fourth matching portion.

According to the urea supply control device of the SCR system according to the present invention, the microcomputer outputs a control signal to the input module through the second matching part to control the control valve of the input module to inject the determined amount of the input urea into the exhaust gas And controls the control valve of the closing module so as to input the determined urea amount while confirming the amount of the urea supplied to the injector based on the input urea amount detecting signal applied through the third matching part from the flow meter of the closing module.

According to another aspect of the present invention, there is provided a method of controlling the supply of urea in an SCR system, the method comprising the steps of: determining an amount of urea supplied to the control module based on an input urea amount detection signal applied from a flow meter of the input module; Wow; Predicting the amount of nitrogen oxides discharged from the reactor based on the amount of injected urea detected by the control module; Determining a quantity of urea to be injected based on the predicted amount of nitrogen oxides, and determining an amount of urea to be injected in accordance with an engine load according to an engine load signal; And the control module controls the control valve of the charging module to inject the determined amount of urea into the exhaust gas.

According to the method of controlling the supply of urea in the SCR system according to the present invention, the control module controls the amount of urea supplied to the injector while confirming the amount of the urea supplied to the injector based on the input urea amount detection signal applied from the flow meter of the injection module And controlling the control valve of the charging module to charge the charging module.

According to the present invention, when the urea is introduced into the exhaust gas flowing into the reactor in the SCR system and the nitrogen oxide of the exhaust gas is removed by the reactor, the amount of nitrogen released from the reactor A sensor for detecting the amount of nitrogen oxides in the exhaust gas outlet of the reactor is provided by predicting the amount of oxide and determining the amount of charged urea based on the amount of discharged nitrogen oxide, It is possible to efficiently remove nitrogen oxides by controlling the amount of injected urea without reducing the equipment cost of the SCR system, and is also very advantageous in maintenance of the SCR system.

1 is a diagram illustrating an apparatus for controlling urea supply in an SCR system according to the present invention.
2 is a diagram illustrating a distribution module applied to the present invention.
3 is a diagram illustrating an input module applied to the present invention.
4 is a diagram illustrating a control module applied to the present invention.
5 is a diagram illustrating a process of controlling urea supply in an SCR system according to the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Although the present invention has been described with reference to the embodiments shown in the drawings, it is to be understood that the present invention is not limited to the technical spirit and essential structure and operation of the present invention.

The present invention relates to a process for removing nitrogen oxides of exhaust gas from a reactor by introducing urea into an exhaust gas flowing into a reactor in a CR system, The amount of the injected urea is determined based on the amount of the discharged urea based on the amount of the discharged nitrogen oxide, and the amount of the injected urea determined by reflecting the engine load is supplied, without installing a sensor for detecting the amount of nitrogen oxide in the exhaust gas outlet of the reactor And the amount of injected urea is adjusted to efficiently remove nitrogen oxides.

As shown in FIG. 1, the urea supply control device of the SCR system according to the present invention includes a tank 110, a distribution module 120, an input module 130, an injector 135, (140).

The tank 110 stores urea in the form of an aqueous solution and applies the urea to the distribution module 120 side. The distribution module 120 pumps and applies the urea applied from the tank 110 to the charging module 130.

The injection module 130 atomizes the urea by the injector 135 by applying the urea which is pressurized and applied from the distribution module 120 together with the compressed air to the injector 135, Gas.

By injecting urea into the exhaust gas flowing into the reactor 200 from the diesel engine, the nitrogen oxide of the exhaust gas is converted into nitrogen and water by the catalyst provided in the reactor 200 and is removed The process of converting nitrogen oxides into nitrogen and water to remove them is well known and a detailed description thereof will be omitted).

The rationing module 120 includes a pump for pumping and pressurizing the urea supplied to the input module 130. The rationing module 120 drives the pump under the control of the control module 140 to pressurize the urea and apply do.

The injection module 130 detects the amount of urea injected into the injector 135 when the urea is injected into the exhaust gas through the injector 135 and transmits the input urea amount detection signal to the control module 140, And controls the amount of urea injected into the injector 135 under the control of the controller 140.

The control module 140 controls the distribution module 120 and the input module 130 to apply the urea to the exhaust gas flowing into the reactor 200. The control module 140 controls the flow rate of the urea based on the input urea amount detection signal And the amount of urea to be injected is determined based on the amount of nitrogen oxides discharged from the reactor 200 based on the amount of injected urea, The input module 130 is controlled. The control module 140 determines the amount of urea to be injected in accordance with the engine load according to the engine load signal applied from the engine in determining the amount of urea to be introduced.

The injection module 130 applies the urea supplied from the distribution module 120 to the injector 135 together with the compressed air to atomize the urea by the injector 135 and inject it into the exhaust gas flowing into the reactor 200 The control module 140 controls the amount of urea to be supplied.

The distribution module 120 includes a plurality of valves V11 and V12 and a pump P as shown in FIG. The pump P is driven in accordance with the control signal 1 applied from the control module 140 to pressurize the urea in the form of an aqueous solution flowing from the tank 110 through the valve V11 and supply the urea in the form of aqueous solution through the valve V12 . The valves V11 and V12 are manually operated to open and close the urea supply piping. The valve V11 manually opens and closes the urea inflow path from the tank 110 and the valve V12 opens and closes the valves V11 and V11. The urea inlet path applied via the pump P is manually opened and closed. The valves V11 and V12 may be useful for maintenance work on the urea supply system.

The input module 130 includes a plurality of valves V21 to V25, a control valve CV, and a flow meter (FM) as illustrated in FIG. The control valve CV regulates the amount of urea in accordance with the control signal 2 applied from the control module 140 and applies the urea amount to the injector 135 to control the amount of urea introduced into the exhaust gas in accordance with the control of the control module 140 . The flow meter FM detects the amount of urea injected into the injector 135 and applies a corresponding detection signal to the control module 140 to notify the control module 140 of the amount of the urea supplied to the control module 140, To predict the amount of nitrogen oxides discharged from the reactor 200 on the basis of the input urea amount and to determine the amount of urea to be supplied based on the amount of nitrogen oxides, And the control valve CV is controlled so as to inject the determined amount of urea.

The valves V21 to V23 are manually operated to open and close the urea supply system. The valve V21 manually opens and closes the urea inflow path applied from the distribution module 120, and the valve V22 opens and closes the valve V21. And the control valve CV, and the valve V23 manually opens and closes the urea inflow path via the flow meter FM. In addition, the valves V24 and V25 are manually operated to open and close the compressed air supply system. The valve V24 manually opens and closes the inflow path of the compressed air, and the valve V25 is connected to the injector 135 are manually opened and closed. Such valves V21 to V25 can be usefully used in maintenance work for the urea supply system and the compressed air supply system. The compressed air flowing in via the valves V24 and V25 is supplied to the valve V21 via the valve V21, the control valve CV, the valve V22, the flow meter FM and the valve V23, And injected into the injector 135 to atomize the urea and inject it into the exhaust gas.

The control module 140 drives the pump P of the distribution module 120 to press the urea and apply the urea to the charging module 130 so that the charging module 130 atomizes the urea through the injector 135, The amount of urea injected through the injector 130 is determined on the basis of the input urea amount detection signal supplied from the flow meter FM of the input module 130 and the amount of urea introduced into the reactor 200, and determines the amount of urea to be injected based on the amount of nitrogen oxides, while determining the amount of urea to be injected in accordance with the engine load according to the engine load signal. The control module 140 controls the control valve CV of the input module 130 so as to input the determined urea amount while confirming the amount of the urea injected into the injector 135 through the flowmeter FM, The amount of urea fed to the injector 135 by the valve CV is adjusted to control the amount of urea injected into the exhaust gas flowing into the reactor 200. Accordingly, the reactor 200 receives the amount of urea corresponding to the amount of nitrogen oxides, and efficiently removes the nitrogen oxides of the exhaust gas.

That is, while the urea is injected into the exhaust gas flowing into the reactor 200 and the reactor 200 removes the nitrogen oxide of the exhaust gas, the control module 140 controls the flow meter The amount of nitrogen oxide discharged from the reactor 200 is predicted on the basis of the amount of input urea obtained through the FM (FM), the amount of charged urea is determined based on the amount of nitrogen oxide, and the amount of charged urea is determined by reflecting the engine load , The control valve CV of the input module 130 is controlled and the determined amount of urea is supplied to the exhaust gas so that the reactor 200 is supplied with the urea amount corresponding to the amount of nitrogen oxide to efficiently reduce the nitrogen oxide of the exhaust gas .

 4, the control module 140 includes a microcomputer 141, a memory 142, a display section 143, an operation section 144, and matching sections 145-148. The microcomputer 141 controls the distribution module 120 and the input module 130 to proceed with the urea supply and performs all control processes for the urea supply control based on the urea supply control program.

The memory 142 estimates the amount of discharged urea from the amount of injected urea based on the amount of injected urea, and determines the amount of injected urea based on the amount of injected urea, And supplies the urea supply control program to the microcomputer 141, thereby causing the microcomputer 141 to perform all control processes for controlling the urea supply. The memory 142 stores various data necessary for the urea supply control under the control of the microcomputer 141 and provides the microcomputer 141 with the data.

Under the control of the microcomputer 141, the display unit 143 displays all data generated during the urea supply adjustment processing so that the data can be visually confirmed.

Then, the operation unit 144 inputs various data and commands for controlling the urea supply to the microcomputer 141 by manual operation of the operator.

The matching unit 145 applies the control signal 1 applied from the microcomputer 141 to the distribution module 120 so that the control signal 1 usable in the pump P of the distribution module 120 is usable, The matching module 147 applies the control signal 2 applied from the microcomputer 141 to the control module CV of the input module 130 so as to be usable and applies the control signal 2 to the input module 130, The input urea amount detection signal that detects the amount of input urea applied from the flow meter FM of the microcomputer 141 is subjected to matching processing so as to be processable by the microcomputer 141 and is applied to the microcomputer 141. [ In addition, the matching section 148 performs matching processing so that the engine load signal applied from the engine can be processed by the microcomputer 141, and applies the processed signal to the microcomputer 141.

The microcomputer 141 outputs the control signal 1 through the matching unit 145 to drive the pump P of the distribution module 120 in accordance with the instruction inputted through the operation unit 144 so that the urea And outputs control signal 2 through matching unit 146 to control control valve CV of input module 130 so that input module 130 atomizes urea through injector 135 By injecting the exhaust gas into the exhaust gas, the reactor 200 proceeds to remove the nitrogen oxide by using the urea.

During the process of removing the nitrogen oxide of the exhaust gas by the reactor 200 as described above, the microcomputer 141 controls the microcomputer 141 based on the detection signal applied from the flow meter FM through the matching unit 147, 130 to determine the amount of urea to be injected into the injector 135 and predict the amount of nitrogen oxides discharged from the reactor 200 based on the amount of supplied urea and determine the amount of urea to be injected based on the amount of nitrogen oxides The amount of injected urea is determined by reflecting the engine load according to the engine load signal input through the matching portion 148. [

 The microcomputer 141 outputs the control signal 2 to the input module 130 through the matching unit 146 and controls the control valve CV of the input module 130 to input the determined amount of urea into the exhaust gas The control unit 150 controls the flow rate of the urea supplied from the flow meter FM to the injector 135 based on the input urea amount detection signal applied through the matching unit 147, The injection module 130 adjusts the amount of urea fed to the injector 135 to control the amount of urea injected into the exhaust gas flowing into the reactor 200 by controlling the CV. Accordingly, the reactor 200 receives the amount of urea corresponding to the amount of nitrogen oxides, and efficiently removes the nitrogen oxides of the exhaust gas.

The urea supply control device of the SCR system according to the present invention having the functions as described above is capable of controlling the amount of urea injected into the exhaust gas flowing into the reactor 200 from the diesel engine of the ship As shown in FIG.

First, the microcomputer 141 of the control module 140 receives the drive command through the operation unit 144, and outputs the control signal 1 through the matching unit 145 according to the drive command, The controller 100 controls the control valve CV of the input module 130 to output the control signal 2 through the matching unit 146 while applying the urea to the input module 130 by driving the input module P, 130 to inject the urea into the exhaust gas through the injector 135 (S100), and the reactor 200 proceeds the process of removing the nitrogen oxide by using the urea.

The microcomputer 141 of the control module 140 receives the detection signal from the flow meter FM of the input module 130 through the matching section 147 while injecting the urea into the exhaust gas as described above The amount of urea to be injected into the injector 135 from the injection module 130 is checked in step S200 and the amount of nitrogen oxide discharged from the reactor 200 on the basis of the amount of injected urea is estimated in step S300.

The microcomputer 141 of the control module 140 determines the amount of injected urea based on the predicted amount of nitrogen oxides, and reflects the engine load according to the engine load signal applied through the matching portion 148 from the engine, The urea amount is determined (S400).

The microcomputer 141 outputs the control signal 2 to the input module 130 through the matching unit 146 to control the control valve CV of the input module 130 to input the determined amount of urea into the exhaust gas The control unit 150 controls the flow rate of the urea supplied from the flow meter FM to the injector 135 based on the input urea amount detection signal applied through the matching unit 147, The injection module 130 controls the amount of urea sent to the injector 135 to control the amount of urea injected into the exhaust gas flowing into the reactor 200 at step S500.

The microcomputer 141 of the control module 140 checks whether a drive end command is input from the operation unit 144 (S600). If the drive end command is not inputted, the microcomputer 141 returns to S200 to perform the above- When the drive end command is inputted, the operation is terminated.

As described above, in the SCR system, when urea is injected into the exhaust gas flowing into the reactor and the nitrogen oxide of the exhaust gas is removed by the reactor, the amount of nitrogen oxide The amount of injected urea is determined based on the predicted amount of nitrogen oxides, the amount of injected urea is determined by reflecting the engine load, and the determined amount of urea is injected into the exhaust gas flowing into the reactor, It is possible to efficiently remove the nitrogen oxides by using the urea by sufficiently receiving the urea necessary for the removal of the nitrogen oxides. Therefore, the present invention effectively removes nitrogen oxides by adjusting the amount of the urea supplied, without providing a sensor for detecting the amount of nitrogen oxides in the exhaust gas outlet of the reactor, thereby reducing the facility cost of the SCR system, It is also very advantageous for maintenance of.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. And such changes are considered to be within the technical scope of the present invention.

The present invention can be applied to the case where urea is injected into the exhaust gas flowing into the reactor in the SCR system in order to purify the exhaust gas of the diesel engine. According to the present invention, when the urea is injected into the exhaust gas flowing into the reactor in the SCR system and the nitrogen oxide of the exhaust gas is removed by the reactor, the amount of nitrogen oxide which is untreated from the reactor and discharged from the reactor, The amount of injected urea is determined based on the estimated amount of nitrogen oxides, the amount of injected urea is determined by reflecting the engine load, and the determined amount of urea is injected into the exhaust gas flowing into the reactor, It is possible to reduce the installation cost of the SCR system and to maintain the maintenance of the SCR system because the nitrogen oxide is efficiently removed by adjusting the amount of the charged urea even without installing a sensor for detecting the amount of nitrogen oxide.

110; Tank 120; Distribution module
130; Input module 135; Injector
140; A control module 141; Microcomputer
142: memory 143; Display portion
144; Operating portions 145 to 148; The matching portion
P; Pump FM; Flow meter
CV; Control valves V11, V12, V21 to V25; valve

Claims (8)

As a urea supply control device of an SCR (Selective Catalytic Reduction) system,
A distribution module for pumping and pressurizing the urea applied from the tank in the form of an aqueous solution under the control of the control module and applying the pressure to the input module;
The urea supplied from the distribution module is applied to the injector together with the compressed air to atomize the urea by the injector and to inject the urea into the exhaust gas flowing into the reactor, An injection module for controlling the amount of injected urea applied to the injector according to the control;
And controlling the distribution module and the input module so as to inject urea into the exhaust gas flowing into the reactor. The amount of the charged urea is detected on the basis of the input urea amount detection signal applied from the input module, The amount of nitrogen oxides discharged from the engine is determined based on the estimated amount of nitrogen oxides, the amount of urea to be injected is determined in accordance with the engine load, Module for controlling the supply of the urea in the SCR system.
The method according to claim 1,
The distribution module includes:
A pump for pumping and pressurizing the urea supplied from the tank according to the control of the control module and applying the pressure to the charging module;
And a plurality of valves for manually opening and closing the urea supply system via the pump.
The method according to claim 1,
The input module includes:
A control valve for controlling the amount of urea applied to the injector from the distribution module under the control of the control module;
A flow meter for detecting an amount of the input urea applied to the injector from the control valve and for applying an input urea amount detection signal to the control module;
A plurality of valves for manually opening and closing the urea supply system via the control valve and the flow meter;
And a plurality of valves for manually opening and closing the supply system of the compressed air to be applied to the injector.
The method according to any one of claims 1 to 3,
The control module includes:
A microcomputer for controlling the distribution module and the input module to perform the urea supply control and performing all control processes for the urea supply control based on the urea supply control program;
A memory for storing the urea supply control program and providing the microcontroller with the urea supply control program according to the control of the microcomputer;
A display unit for displaying various data generated in the urea supply adjusting process under the control of the microcomputer;
An operation unit for inputting various data and commands for controlling the urea supply by manual operation to the microcomputer;
A first matching unit for matching a control signal applied from the microcomputer so as to be usable in the distribution module;
A second matching unit for matching a control signal applied from the microcomputer so as to be usable in the input module;
A third matching unit for matching the input urea amount detection signal applied from the input module so that the input urea amount detection signal can be processed by the microcomputer;
And a fourth matching section for matching the engine load signal applied from the engine so as to be processable by the microcomputer.
The method of claim 4,
The microcomputer calculates the amount of the charged urea based on the detection signal applied through the third matching unit from the input module, predicts the amount of nitrogen oxide discharged from the reactor based on the amount of the supplied urea, And the amount of urea to be introduced is determined based on the engine load according to the engine load signal applied through the fourth matching portion.
The method of claim 5,
The microcomputer controls the control valve of the input module by outputting a control signal to the input module through the second matching unit to input the determined amount of the input urea into the exhaust gas. The input signal from the flowmeter of the input module, And controls the control valve of the injection module so as to inject the determined urea amount while confirming the amount of the urea supplied to the injector based on the urea amount detection signal.
As a method for controlling urea supply in an SCR (Selective Catalytic Reduction) system,
The control module recognizing the amount of charged urea based on the input urea amount detection signal applied from the flow meter of the input module;
Predicting the amount of nitrogen oxides discharged from the reactor based on the amount of injected urea detected by the control module;
Determining a quantity of urea to be injected based on the predicted amount of nitrogen oxides, and determining an amount of urea to be injected in accordance with an engine load according to an engine load signal;
And the control module controls the control valve of the input module to inject the determined amount of urea into the exhaust gas.
The method of claim 7,
The control module may further include a step of controlling the control valve of the charging module so as to inject the determined amount of urea while confirming the amount of the charged urea supplied to the injector based on the input urea amount detection signal applied from the flow meter of the charging module A method of controlling urea supply in an SCR system.

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