Device and method for adjusting and controlling actual supplied amount of urea entering an exhaust system

Abstract

A device for adjusting and controlling the actual supplied amount of urea entering an exhaust system comprises an electronic control unit ( 1 ), a compressed air supply device ( 2 ), a urea storage device ( 3 ), a compressed air control device ( 4 ), a metering pump or a metering valve ( 5 ), a spray nozzle ( 6 ), a main pipeline ( 7 ), a urea pipeline ( 8 ), and a urea control device ( 9 ). The urea control device ( 9 ) is in communication with the electronic control unit ( 1 ) and controls the actual supplied amount of urea injected into the exhaust system from the spray nozzle according to the starting time point and the finishing time point. A method for adjusting and controlling the actual supplied amount of urea entering an exhaust system is also disclosed. The present device and method effectively prevent the excessive urea from being injected into the exhaust system, and enable the original exhaust system to match with stricter emission standards through a low cost improvement.

1 . A device for adjusting and controlling the actual supplied amount of urea entering an exhaust system, comprising an electronic control unit( 1 ), a compressed air supply device( 2 ), a urea storage device( 3 ), a compressed air control device( 4 ), a metering pump or a metering valve( 5 ), a spray nozzle( 6 ), a main pipeline( 7 ) and a urea pipeline( 8 );
 the said electronic control unit( 1 ) is connected with the internal combustion engine of the exhaust system, which is used for collecting the performance parameters of the internal combustion engine and calculating the target supplied amount of urea in the exhaust system and further for determining the starting and finishing of the time points; the said urea storage device( 3 ) is provided for storing the urea; the said compressed air supply device ( 2 ) is connected to the main pipeline( 7 ); the said compressed air control device( 4 ) is installed at the point where the compressed air supply device( 2 ) is connected to the main pipeline( 7 ), and the said compressed air control device( 4 ) communicates with the electronic control unit( 1 ) to control the flow rate of the compressed air sprayed into the main pipeline( 7 ); a through hole is formed in the middle section of the main pipeline( 7 ); the two ends of the urea pipeline( 8 ) is connected to the said urea storage device( 3 ) and the through hole respectively; the said metering pump or the metering valve( 5 ) is installed to the urea pipeline( 8 ) and communicates with the electronic control unit( 1 ), which controls the volume of the urea flowed into the main pipeline( 7 ) from the urea storage device( 3 ); the outlet of the main pipeline( 7 ) extends into the exhaust system; the said spray nozzle( 6 ) is installed at the said outlet of the main pipeline( 7 ) so that the urea is introduced into the exhaust system by spray; the urea is mixed with the compressed air in the main pipeline( 7 ); wherein the said device further comprises an urea control device( 9 ), which is installed to the main pipeline( 7 ), and communicates with the electronic control unit( 1 );   the said urea control device( 9 ) is provided, when the urea is controlled to enter the exhaust system, the compressed air is provided into the main pipeline( 7 ), so that the urea in the main pipeline( 7 ) will enter into the spray nozzle( 6 ) by the compressed air and further be injected into the exhaust system in the spay-like form;   when the urea is controlled to be held from entering the exhaust system, the compressed air is provided into the spray nozzle( 6 ) without passing through the main pipeline( 7 ), causing the urea in the main pipeline( 7 ) to be stopped entering the spray nozzle( 6 ) and stopped entering the exhaust system.   
     
     
         2 . The device for adjusting and controlling the actual supplied amount of urea entering an exhaust system according to  claim 1 , wherein the said urea control device( 9 ) comprises a three-way valve( 94 ) and an branch airway( 95 ); the said three-way valve( 94 ) is installed to the section of the main pipeline( 7 ) between the compressed air control device( 4 ) and the through hole; the inlet of the three-way valve( 94 ) is connected to the compressed air control device( 4 ) while the first outlet thereof is connected to the main pipeline( 7 ) and the second outlet thereof is connected to an end of the said branch airway( 95 ); the other end of the branch airway( 95 ) is connected to the main pipeline( 7 ), the connecting points are located between the urea pipeline( 8 ) and the spray nozzle( 6 ); the three-way valve( 94 ) communicates with the electronic control unit( 1 );
 when the urea is controlled to enter the exhaust system, the three-way valve( 94 ) connects the compressed air supply device( 2 ) to the main pipeline( 7 ), allowing the compressed air to be provided into the main pipeline( 7 );   when the urea is controlled to be stopped entering the exhaust system, the three-way valve( 94 ) connects the compressed air supply device( 2 ) to the branch airway( 95 ), allowing the compressed air to enter the spray nozzle( 6 ) through the branch airway( 95 ).   
     
     
         3 . The device for adjusting and controlling the actual supplied amount of urea entering an exhaust system according to  claim 1 , wherein,
 the said urea control device( 9 ) is provided, when the urea is controlled to be stopped entering the exhaust system, the compressed air is changed to be prevented from entering the spray nozzle( 6 ), so that the urea will not be entered into the spray nozzle( 6 ) and be stopped entering into the exhaust system.   
     
     
         4 . The device for adjusting and controlling the actual supplied amount of urea entering an exhaust system according to  claim 3 , wherein the said urea control device( 9 ) comprises a control valve( 91 ); the said control valve( 91 ) is installed to the main pipeline( 7 ) between the urea pipeline( 8 ) and the spray nozzle( 6 ); the control valve( 91 ) communicates with the electronic control unit( 1 ), which switches on and off the connection between the main pipeline( 7 ) and the spray nozzle( 6 ) by switching the control valve( 91 ) to an open position or to a close position. 
     
     
         5 . The device for adjusting and controlling the actual supplied amount of urea entering an exhaust system according to  claim 3 , wherein the said urea control device( 9 ) further comprises a bypass channel( 92 ) and a bypass control valve( 93 ); the said bypass channel( 92 ) is connected to the main pipeline( 7 ) with the connecting point located between the urea pipeline( 8 ) and the spray nozzle( 6 ); the said bypass control valve( 93 ) is installed to the bypass channel( 92 ) and communicates with the electronic control unit( 1 ), the electronic control unit ( 1 ) switches the bypass control valve( 93 ) to an open position for allowing the compressed air to enter the external atmosphere through the bypass channel( 92 ) and switches the bypass control valve ( 93 ) to a close position for allowing the compressed air to enter the spray nozzle( 6 ). 
     
     
         6 . The device for adjusting and controlling the actual supplied amount of urea entering an exhaust system according to  claim 5 , wherein the connecting point of one end of the bypass channel( 92 ) connected to the main pipeline( 7 ) is located the upstream of the control valve( 91 ); by switching the control valve( 91 ) to the close position and the bypass control valve( 93 ) to the open position, the compressed air is allowed to enter the bypass channel( 92 ); whereas by switching the control valve( 91 ) to the open position and the bypass control valve( 93 ) to the close position, the compressed air is allowed to enter the spray nozzle( 6 ). 
     
     
         7 . The device for adjusting and controlling the actual supplied amount of urea entering an exhaust system according to  claim 5 , wherein the other end of the bypass channel( 92 ) is further connected to the urea storage device( 3 ); by switching the bypass control valve( 93 ) to the open position, the compressed air is allowed to enter the urea storage device( 3 ) through the bypass channel( 92 ). 
     
     
         8 . A method provided for adjusting and controlling the actual supplied amount of urea entering an exhaust system, wherein the said method comprises:
 Step 1: collecting the performance parameters of the exhaust system and the internal combustion engine, and calculating the target supplied amount of urea entered into the exhaust system and further determining the starting and finishing time point;   Step 2: the compressed air supply device( 2 ) providing the compressed air into the main pipeline( 7 ), while the urea storage device( 3 ) providing the aqueous urea into the main pipeline( 7 ) through the urea pipeline( 8 ), so that the urea and the compressed air are mixed in the main pipeline( 7 ); both the provided volume of the urea and the flow rate of the compressed air are determined according to the target supplied amount of urea;   Step 3: by referring to the starting time point, when the urea is controlled to enter the exhaust system, the compressed air is provided into the main pipeline( 7 ) so that the urea in the main pipeline( 7 ) is fed into the spray nozzle( 6 ) by the compressed air and further provided into the exhaust system in the spray-like form; by referring to the finishing time point, when the urea is controlled to be stopped entering the exhaust system, the compressed air is provided into the spray nozzle( 6 ) without passing through the main pipeline( 7 ), so that the urea in the main pipeline( 7 ) is stopped to be fed into the spray nozzle( 6 ) and further stopped entering into the exhaust system.   
     
     
         9 . The method provided for adjusting and controlling the actual supplied amount of urea entering an exhaust system according to  claim 8 , wherein the said Step 3 further comprises: when the urea is controlled to enter the exhaust system, the three-way valve( 94 ) connects the compressed air supply device( 2 ) to the main pipeline( 7 ), allowing the compressed air to enter the main pipeline( 7 ); when the urea is controlled to be stopped entering the exhaust system, the three-way valve( 94 ) connects the compressed air supply device( 2 ) to the branch airway( 95 ), allowing the compressed air to enter the spray nozzle( 6 ) through the branch airway( 95 ). 
     
     
         10 . The method provided for adjusting and controlling the actual supplied amount of urea entering an exhaust system according to  claim 9 , wherein when the target supplied amount of urea is below the pre-set threshold, the three-way valve ( 94 ) is controlled to connect to the main pipeline( 7 ) intermittently so that the compressed air is provided into the main pipeline( 7 ) intermittently, causing the remained urea in the main pipeline( 7 ) to enter the spray nozzle( 6 ). 
     
     
         11 . The method provided for adjusting and controlling the actual supplied amount of urea entering an exhaust system according to  claim 8 , wherein the said Step 3 is replaced by following:
 when the urea is controlled to enter the exhaust system, the compressed air is provided into the main pipeline( 7 ) by referring to the starting time point, so that the urea in the main pipeline( 7 ) is fed into the spray nozzle( 6 ) by the compressed air and further provided into the exhaust system in the spray-like form; when the urea is controlled to be stopped injecting into the exhaust system, the compressed air is prevented from entering the spray nozzle( 6 ), so that the urea is stopped being fed into the spray nozzle( 6 ) and further into the exhaust system.   
     
     
         12 . The method provided for adjusting and controlling the actual supplied amount of urea entering an exhaust system according to  claim 11 , wherein the said Step 3 comprises installing the control valve( 91 ) to the main pipeline( 7 ); the control valve( 91 ) is shifted between an open position and a close position to switch on and off the connection between the main pipeline( 7 ) and the spray nozzle( 6 ). 
     
     
         13 . The method provided for adjusting and controlling the actual supplied amount of urea entering an exhaust system according to  claim 11 , wherein the said Step 3 further comprises installing a bypass channel( 92 ) and a bypass control valve( 93 ) outside the pipeline; when the bypass control valve( 93 ) is shifted to the open position, the compressed air is allowed to enter the external atmosphere through the bypass channel( 92 ), whereas when the bypass control valve( 93 ) is shifted to the close position, the compressed air is allowed to enter the spray nozzle( 6 ). 
     
     
         14 . The method provided for adjusting and controlling the actual supplied amount of urea entering an exhaust system according to  claim 13 , wherein the said Step 3 further comprises that the connecting point of the bypass channel( 92 ) with the main pipeline( 7 ) is located at the upstream of the control valve( 91 ); by switching the control valve( 91 ) to the close position and the bypass control valve( 93 ) to the open position, the compressed air is allowed to enter the bypass channel( 92 ); whereas by switching the control valve( 91 ) to the open position and the bypass control valve( 93 ) to the close position, the compressed air is allowed to enter the spray nozzle( 6 ). 
     
     
         15 . The method provided for adjusting and controlling the actual supplied amount of urea entering an exhaust system according to  claim 13 , wherein the said Step 3 further comprises that the other end of the bypass channel( 92 ) is further connected to the urea storage device( 3 ); by switching the bypass control valve( 93 ) to the open position, the compressed air is allowed to be fed into the urea storage device( 3 ) through the bypass channel( 92 ). 
     
     
         16 . The device for adjusting and controlling the actual supplied amount of urea entering an exhaust system according to  claim 4 , wherein the said urea control device( 9 ) further comprises a bypass channel( 92 ) and a bypass control valve( 93 ); the said bypass channel( 92 ) is connected to the main pipeline( 7 ) with the connecting point located between the urea pipeline( 8 ) and the spray nozzle( 6 ); the said bypass control valve( 93 ) is installed to the bypass channel( 92 ) and communicates with the electronic control unit( 1 ), the electronic control unit ( 1 ) switches the bypass control valve( 93 ) to an open position for allowing the compressed air to enter the external atmosphere through the bypass channel( 92 ) and switches the bypass control valve ( 93 ) to a close position for allowing the compressed air to enter the spray nozzle( 6 ). 
     
     
         17 . The method provided for adjusting and controlling the actual supplied amount of urea entering an exhaust system according to  claim 12 , wherein the said Step 3 further comprises installing a bypass channel( 92 ) and a bypass control valve( 93 ) outside the pipeline; when the bypass control valve( 93 ) is shifted to the open position, the compressed air is allowed to enter the external atmosphere through the bypass channel( 92 ), whereas when the bypass control valve( 93 ) is shifted to the close position, the compressed air is allowed to enter the spray nozzle( 6 ).