Patent Publication Number: US-2023144474-A1

Title: System and method for removing residual reductant

Description:
TECHNICAL FIELD 
     The present disclosure relates to an aftertreatment system and a reductant dosing system associated with the aftertreatment system. More particularly, the present disclosure relates to a system and a method for removing residual reductant from one or more components of the reductant dosing system. 
     BACKGROUND 
     Exhaust gases exiting an engine system may contain high concentrations of particulate matter, such as, oxides of nitrogen, carbon monoxide, ammonia, and the like. In order to comply with emission regulation standards, the engine system includes an aftertreatment system. The aftertreatment system may remove and/or control the particulate matter that may be present in the exhaust gases, prior to the exhaust gases exiting into atmosphere. 
     Aftertreatment systems typically include a diesel oxidation catalyst and a selective catalytic reduction (SCR) device. Before the exhaust gases enter the SCR module, a reductant, such as diesel exhaust fluid, may be dosed into the exhaust gases. The reductant is typically dosed by a reductant dosing system. In air assisted reductant dosing systems, an injector receives a supply of air and the reductant. The injector serves to direct a predetermined spray pattern of the air and the reductant towards the exhaust gases. Further, a pump may be used to direct a pressurized flow of the reductant towards the injector. Moreover, a manifold may receive air from an air supply source and the reductant from the pump. When the aftertreatment system is not in use, a removal of residual reductant may be desirable as the reductant is susceptible to freezing in cold temperatures which may damage one or more components of the of the aftertreatment system. 
     A primary purging circuit may be associated with the aftertreatment system to purge the reductant from various portions of the aftertreatment system. However, in some cases, the reductant may not completely purge after engine shut-down. For example, some components of the reductant dosing system, such as, the manifold, the pump, and/or pump valves (for e.g., check valves) associated with the pump may not fully purge post a purging process performed by the primary purging circuit. In some examples, purging of the pump valves may be difficult as the pump valves limit flow in one direction. 
     Further, if the components are not purged completely, residual reductant present in the components of the reductant dosing system may freeze when the engine system is put into long term storage. The freezing of the reductant may damage the components of the reductant dosing system thereby increasing maintenance and/or replacement costs. In some examples, the residual reductant may freeze and crack pump hardware/manifolds. 
     CN213088097U describes a novel anti-freezing SCR system comprises a urea box, a urea liquid supply pump, an SCR module body, a filter, a urea injector and a sweeping pump, the module body comprises a liquid outlet channel and a liquid return channel, the urea liquid supply pump comprises a liquid supply injector, the urea injector comprises a liquid inlet injector and a liquid return injector, and the liquid inlet injector is communicated with the liquid return channel. The liquid supply injector is connected with one end of a liquid outlet channel of the SCR module body through a liquid supply pipe, the other end of the liquid outlet channel is connected to a liquid inlet injector of the urea injector through a high-pressure pipe to form a urea solution supply flow channel, and a liquid return injector of the urea injector is connected to one end of a liquid return channel of the SCR module body through a liquid return pipe. and the other end of the liquid return channel is connected with the interior of the urea box to form a urea liquid return flow channel. And the cleaning pump sucks gas in the upper space of the urea box, blows the gas into the urea solution supply flow channel, returns to the urea box through the urea solution backflow channel, and brings out the residual urea solution in the pipeline. 
     SUMMARY OF THE DISCLOSURE 
     In one aspect of the present disclosure, a system for removing residual reductant from at least one component of a reductant dosing system associated with an aftertreatment system is provided. The system includes a first container disposed in fluid communication with the reductant dosing system. The system also includes a first conduit for providing the fluid communication between the first container and the reductant dosing system. Based on a generation of a vacuum within the first container, the first conduit is operative to remove the residual reductant from the at least one component of the reductant dosing system and introduce the residual reductant into the first container. 
     In another aspect of the present disclosure, a method for removing residual reductant from at least one component of a reductant dosing system associated with an aftertreatment system is provided. The method includes providing fluid communication between a first container and the reductant dosing system. A first conduit provides the fluid communication between the first container and the reductant dosing system. The method also includes generating a vacuum within the first container. The method further includes removing the residual reductant from the at least one component of the reductant dosing system based on the generation of the vacuum within the first container. The method includes introducing, by the first conduit, the residual reductant into the first container. 
     Other features and aspects of this disclosure will be apparent from the following description and the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    illustrates a schematic view of an engine system and an aftertreatment system associated with the engine system, according to examples of the present disclosure; 
         FIG.  2    illustrates a cross-sectional view of a pump of a reductant dosing system associated with the aftertreatment system of  FIG.  1   , according to examples of the present disclosure; 
         FIG.  3    illustrates a schematic diagram illustrating a system for removing residual reductant from one or more components of the reductant dosing system, according to examples of the present disclosure; 
         FIG.  4    illustrates a schematic diagram illustrating the system for removing the residual reductant from the one or more components of the reductant dosing system, according to another example of the present disclosure; and 
         FIG.  5    illustrates a flowchart for a method for removing the residual reductant from the one or more components of the reductant dosing system, according to examples of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. Wherever possible, corresponding or similar reference numbers will be used throughout the drawings to refer to the same or corresponding parts. 
       FIG.  1    illustrates a schematic view of an engine system  100 , according to an embodiment of the present disclosure. The engine system  100  may be used in a variety of machines (not shown) including, but not limited to, mobile machines (such as, construction machines), stationary machines, and like. The engine system  100  includes an engine  102 . The engine  102  may be any type of engine (internal combustion, gas, diesel, gaseous fuel, natural gas, propane, etc.), may be of any size, with any number of cylinders, any type of combustion chamber (cylindrical, rotary spark ignition, compression ignition, 4-stroke and 2-stroke, etc.), and in any configuration (“V,” in-line, radial, etc.). 
     The engine  102  may include a number of components (not shown) such as a crankshaft, a fuel system, an inlet manifold, an intake port, an exhaust port, and the like. Further, the engine  102  may include a number of cylinders  104  that define one or more combustion chambers (not shown). Moreover, exhaust gases generated based on combustion of fuels in the combustion chambers may be directed towards an exhaust manifold  106  of the engine  102 . The exhaust manifold  106  may be in fluid communication with the cylinders  104 . It should be noted that the exhaust gases exiting the engine  102  may include particulate matter, such as, carbon monoxide (CO), ammonia, and Oxides of Nitrogen (NOx), such as, Nitric Oxide (NO), Nitrous Oxide (N 2 O), and Nitrogen Dioxide (NO 2 ). 
     The engine system  100  may include an aftertreatment system  108  for treatment of the exhaust gases exiting the engine  102 . The aftertreatment system  108  may operate to reduce/eliminate a concentration of the particulate matter in the exhaust gases, before the exhaust gases are let into the atmosphere. The aftertreatment system  108  may be in fluid communication with the exhaust manifold  106  of the engine  102 . The exhaust gases may flow through the aftertreatment system  108  along an exhaust gas flow path “F 1 ”. Further, the aftertreatment system  108  may include various components (not shown), such as, a particulate filter for reducing a content of particulate matter in the exhaust gases, an Ammonia Slip Catalyst (ASC), and the like. 
     The aftertreatment system  108  may include a first module  110  in fluid communication with the exhaust manifold  106  and positioned downstream of the engine  102  in the exhaust gas flow path “F 1 ”. As illustrated in  FIG.  1   , the first module  110  may be in fluid communication with the exhaust manifold  106  via a first exhaust conduit  112 . The first module  110  may include a diesel oxidation catalyst. In some examples, the first module  110  may include a diesel oxidation catalyst as well as a diesel particulate filter. Alternatively, the first module  110  may include any other suitable exhaust treatment device. The first module  110  may include a canister and one or more catalysts disposed within the canister. The exhaust gases exiting the engine  102  may contain some amount of ammonia present therein. The first module  110  may receive the exhaust gases exiting the engine  102  for oxidizing the ammonia present in the exhaust gases into NOx. In some examples, the first module  110  may oxidize NO to convert NO into NO 2 , thereby, changing a ratio of NO:NO 2  within the exhaust gases. 
     The aftertreatment system  108  may also include a second module  114  in fluid communication with the first module  110  and positioned downstream of the engine  102  in the exhaust gas flow path “F 1 ”. The second module  114  may be in fluid communication with the first module  110  via a second exhaust conduit  116 . The second module  114  may embody a selective reductant catalyst (SCR) device. Alternatively, the second module  114  may include any other suitable exhaust treatment device. The second module  114  may include a canister and one or more catalysts disposed within the canister for facilitating reaction, reduction, and removal of NOx from the exhaust gases passing therethrough. The second module  114  may convert NOx into nitrogen (N 2 ) and water (H 2 O). 
     In some examples, the aftertreatment system  108  may include one or more sensors (not shown) for determining a quantity of particulate matter present in the exhaust gases flowing through the aftertreatment system  108 . In an example, the one or more sensors may include a NOx sensor. In some examples, the aftertreatment system  108  may include a first sensor disposed between the exhaust manifold  106  and the first module  110 . The aftertreatment system  108  may also include a second sensor disposed between the first module  110  and the second module  114 . The aftertreatment system  108  may further include a third sensor disposed at an exit of the second module  114 . 
     The aftertreatment system  108  also includes a reductant dosing system  118  for dosing a reductant in the exhaust gases exiting the first module  110 . The reductant may include a diesel exhaust fluid. The reductant may contain a urea based solution, without any limitations. It should be noted that the reductant may include any other type of fluid that is dosed into the exhaust gases, known to a person having ordinary skill in the art. In the illustrated example of  FIG.  1   , the reductant dosing system  118  includes an air-assisted reductant dosing system. 
     The reductant dosing system  118  includes an injector  120  for dosing a mixture of the reductant and air into a stream of exhaust gases “F 2 ”. Specifically, the injector  120  may dose the mixture of the reductant and air into the stream of exhaust gases “F 2 ” exiting the first module  110 . The injector  120  may be disposed downstream of the first module  110  and may project inside the second exhaust conduit  116 . The injector  120  may spray the mixture of the reductant and air based on a predefined spray pattern. In some examples, the injector  120  may combine the reductant with air to produce an atomized spray, which may be introduced into the stream of exhaust gases “F 2 ”. 
     In various examples, the reductant dosing system  118  may include a single injector or multiple injectors. In the illustrated example of  FIG.  1   , the reductant dosing system  118  includes the single injector  120 . It should be noted that an amount of air and the reductant dosed into the stream of exhaust gases “F 2 ” may be varied based on an amount of the particulate matter present in the stream of exhaust gases “F 2 ”. In an example, the injector  120  may be controlled to vary the amount of air and the reductant that is dosed into the stream of exhaust gases “F 2 ”. 
     The reductant dosing system  118  includes an air supply device  122 . The air supply device  122  may be in fluid communication with the injector  120 , via an air supply conduit  124  and a manifold  126 . The air supply device  122  may compress air and direct the compressed air towards the injector  120 , via the air supply conduit  124  and the manifold  126 . In some examples, the air supply device  122  may include a compressor, without any limitations. It should be noted that the present disclosure is not limited by a type of the air supply device  122 . Further, the reductant dosing system  118  may include additional components (not shown herein) for directing the air towards the injector  120 . 
     The reductant dosing system  118  also includes a reservoir  128 . The reservoir  128  may store the reductant therein and may supply the reductant towards the injector  120 , as and when desired. The reductant dosing system  118  includes a pump  130  for directing the reductant towards the manifold  126 . The pump  130  may be in fluid communication with the reservoir  128  for receiving the reductant from the reservoir  128 . A first reductant supply conduit  140  may provide the fluid communication between the reservoir  128  and the pump  130 . The pump  130  may pressurize the reductant and direct the pressurized reductant towards the injector  120 . As shown in  FIG.  2   , the pump  130  may include a first pump valve  132  that may be disposed between the reservoir  128  and the pump  130 . Moreover, the pump  130  may include a second pump valve  134  that may be disposed between the pump  130  and the injector  120 . In some examples, the first and second pump valves  132 ,  134  may embody unidirectional valves. In various examples, the first and second pump valves  132 ,  134  may embody check valves, butterfly valves, flap valves, or any other form of valves, without any limitations. 
     In the illustrated example of  FIG.  2   , the pump  130  is embodied as a diaphragm-type pump. Accordingly, the pump  130  may include a diaphragm  136 . Alternatively, the pump  130  may embody any other type of pump known in the art, without any limitations. The pump  130  may include a pump chamber  138 . The reductant may be introduced in the pump chamber  138  through the first pump valve  132 . Further, the reductant may exit the pump chamber  138  via the second pump valve  134 . Moreover, a second reductant supply conduit  142  may establish a fluid communication between the pump  130  and the manifold  126 . A flow path “F 3 ” defined by the pump  130  for passage of the reductant is illustrated in  FIG.  2   . 
     The reductant dosing system  118  may further include the manifold  126  for directing the mixture of reductant and air towards the injector  120 . The manifold  126  may be in fluid communication with the air supply device  122  via the air supply conduit  124  for receiving air from the air supply device  122 . Further, the manifold  126  may be in fluid communication with the pump  130  via the second reductant supply conduit  142  for receiving the reductant from the pump  130 . The manifold  126  may further direct the air and the reductant towards the injector  120 . 
     Further, the reductant dosing system  118  may be purged after a shut-down of the engine system  100  to remove the reductant from various components of the reductant dosing system  118 . Thus, the aftertreatment system  108  may include a primary purging system (not shown) generally known in the art that may purge the reductant from injector  120 . However, the primary purging system may not effectively remove the reductant present in the manifold  126 , the pump  130 , and/or the first and second pump valves  132 ,  134 . If the engine system  100  is non-operational for a prolong period of time, the reductant present in the manifold  126 , the pump  130 , and/or the first and second pump valves  132 ,  134  may freeze, which may not be desirable. 
     Referring to  FIG.  3   , the present disclosure relates to a system  300  for removing residual reductant from one or more components of the reductant dosing system  118 . In some examples, the one or more components may include the pump  130 , the one or more pump valves  132 ,  134  associated with the pump  130 , and/or the manifold  126 . In some examples, the system  300  may also remove the residual reductant from the pump chamber  138  and/or the first and second reductant supply conduits  140 ,  142 . The system  300  includes a first container  302  disposed in fluid communication with the reductant dosing system  118 . The first container  302  may include any shape, size, or material, as per application requirements. In some examples, the first container  302  may include a bucket. 
     Further, the system  300  includes a first conduit  304  for providing the fluid communication between the first container  302  and the reductant dosing system  118 . The first conduit  304  may include any shape, size, or material, as per application requirements. In some examples, the first conduit  304  may embody a flexible hose, without any limitations. The first conduit  304  may include a first end  306  and a second end  308 . The first end  306  of the first conduit may be in fluid communication with the first container  302  and the second end  308  of the first conduit  304  may be in fluid communication with the reductant dosing system  118 . In some examples, the second end  308  of the first conduit  304  may connect to a port (not shown) defined in the second reductant supply conduit  142  that connects the pump  130  to the injector  120 . 
     Further, based on a generation of a vacuum within the first container  302 , the first conduit  304  removes the residual reductant from the one or more components of the reductant dosing system  118  and introduces the residual reductant into the first container  302 . According to one example of the present disclosure, the system  300  may include a vacuum pump  310 . The vacuum pump  310  may embody a positive displacement type of vacuum pump, a momentum transfer type of vacuum pump, or a regenerative type of vacuum pump. It should be noted that a type of the vacuum pump  310  does not limit the scope of the present disclosure. In some examples, the vacuum pump  310  may be replaced by a hand-operated pump, without any limitations. 
     In an example, the vacuum may be generated within the first container  302  based on an activation of the vacuum pump  310 . The vacuum pump  310  may be in communication with the first container  302  via a conduit  312 . Based on the activation of the vacuum pump  310 , the vacuum may be generated within the first container  302  which may in turn draw the residual reductant from the manifold  126 , the first and second pump valves  132 ,  134 , the pump chamber  138 , the first and second reductant supply conduits  140 ,  142 , and/or other components of the pump  130 , via the first conduit  304 . 
     Specifically, based on the generation of the vacuum in the first container  302 , a suction force may be generated within the first conduit  304 , and the first and second reductant supply conduit  140 ,  142  along the flow path “F 3 ” (see  FIG.  1   ), which may draw the residual reductant from various components of the reductant dosing system  118  into the first container  302 . Further, the residual reductant may be removed from the one or more pump valves  132 ,  134  on account of an opening of the one or more pump valves  132 ,  134  due to the vacuum generated in the first container  302 . Specifically, the one or more pump valves  132 ,  134  may open based on the suction force generated within the first conduit  304  and the first and second reductant supply conduit  140 ,  142  due to the vacuum generated in the first container  302 . 
     In some examples, the first container  302  may contain fluid therein. In an example, the first container  302  may contain water therein. The residual reductant removed from the components of the reductant dosing system  118  may be diluted with the fluid in the first container  302  before disposal. 
     According to a second example of the present disclosure, the system  300  may include a valve  314  disposed in fluid communication with the first container  302 . The valve  314  may be disposed along a conduit  316  such that the valve  314  may be in fluid communication with the first container  302 . The valve  314  may be operated to switch the valve  314  between an open position and a closed position. The valve  314  may embody an electrically operated valve, a hydraulically operated valve, and the like, without any limitations. The valve  314  may include a gate valve (or multiturn valve), a check valve, and the like. The valve  314  may include a hand-operated valve or a foot-operated valve. In some examples, the valve  314  may be switched between the open and closed positions by a service personnel. It should be noted that the valve  314  may include any type of valve generally known in the art, without any limitations. 
     According to the second example of the present disclosure, the vacuum may be generated within the first container  302  based on a draining of the fluid from the first container  302 . More specifically, the valve  314  may be operated to switch the valve  314  to the open position. Based on an opening of the valve  314 , a portion of the fluid may drain from the first container  302 , via the conduit  316 . The draining of the fluid may generate the vacuum within the first container  302  which may in turn draw the residual reductant from the manifold  126 , the first and second pump valves  132 ,  134 , the pump chamber  138 , the first and second reductant supply conduits  140 ,  142 , and/or other components of the pump  130 , via the first conduit  304 . Further, the residual reductant removed from the components of the reductant dosing system  118  may be diluted with the fluid in the first container  302  before disposal. 
       FIG.  4    illustrates a third example of the present disclosure. According to the third example, the vacuum may be generated within the first container  302  based on the draining of the fluid from the first container  302  by siphoning. Further, the system  300  may include a second container  318  in fluid communication with the first container  302 . The second container  318  may include any shape, size, or material, as per application requirements. In some examples, the second container  318  may include a bucket. 
     The system  300  may also include a second conduit  320  for providing the fluid communication between the first container  302  and the second container  318 . The second conduit  320  may include any shape, size, or material, as per application requirements. As illustrated in  FIG.  4   , the second conduit  320  may include an inverted U-shaped design, without any limitations. In some examples, the second conduit  320  may embody a flexible hose, without any limitations. The second conduit  320  may include a third end  322  and a fourth end  324 . The third end  322  of the first conduit  304  may be in fluid communication with the first container  302  and the fourth end  324  of the second conduit  320  may be in fluid communication with the second container  318 . 
     In the illustrated example of  FIG.  4   , the vacuum may be generated within the first container  302  based on directing, via the second conduit  320 , the portion of the fluid from the first container  302  towards the second container  318 . Further, based on the draining of the fluid from the first container  302  by siphoning, the vacuum may be generated within the first container  302  which in turn draws the residual reductant from the manifold  126 , the first and second pump valves  132 ,  134 , the pump chamber  138 , the first and second reductant supply conduits  140 ,  142 , and/or other components of the pump  130 , via the first conduit  304 . Further, the residual reductant removed from the components of the reductant dosing system  118  may be diluted with the fluid in the first container  302  before disposal. 
     INDUSTRIAL APPLICABILITY 
     The present disclosure relates to the system  300  and a method  500  for removing the residual reductant from one or more components of the reductant dosing system  118 . In an example, the system  300  may remove the residual reductant from the manifold  126 , the first and second pump valves  132 ,  134 , the pump chamber  138 , the first and second reductant supply conduits  140 ,  142 , and/or other components of the pump  130 . Specifically, the system  300  described herein may be embodied as a secondary purging circuit. The system  300  may remove the residual reductant from various components of the reductant dosing system  118  that may not fully purge using the primary purge circuit associated with the aftertreatment system  108 . In some examples, the system  300  may be operated after the shut-down of the engine system  100  for purging of the various components of the reductant dosing system  118 . Further, the system  300  may allow purging of the unidirectional pump valves  132 ,  134  as air from the first container  302  may fill the void left by the residual reductant. 
     The system  300  and the method  500  described herein may reduce a possibility of failure of the components of the reductant dosing system  118  under freezing conditions when the engine system  100  has not been operated for a prolonged period of time. Further, the system  300  and the method  500  may reduce a possibility of any other failure due to retention of the residual reductant within the components of the reductant dosing system  118  after the shut-down of the engine system  100 . The system  300  described herein may provide a cost-effective technique for removing the residual reductant from the components of the reductant dosing system  118 . Further, the system  300  described herein may be easy to operate and may allow quick removal of the residual reductant from the components of the reductant dosing system  118 . 
       FIG.  5    illustrates a flowchart for the method  500  for removing the residual reductant from one or more components of the reductant dosing system  118  associated with the aftertreatment system  108 . The reductant dosing system  118  includes the air-assisted dosing system. The reductant dosing system  118  includes the injector  120  for dosing the mixture of the reductant and air into the stream of exhaust gases “F 2 ”. The reductant dosing system  118  also includes the manifold  126  for directing the mixture of the reductant and air towards the injector  120 . The reductant dosing system  118  further includes the pump  130  for directing the reductant towards the manifold  126 . Further, the one or more components may include the pump  130 , the one or more pump valves  132 ,  134  associated with the pump  130 , and/or the manifold  126 . 
     At step  502 , the fluid communication is provided between the first container  302  and the reductant dosing system  118 . The first conduit  304  provides the fluid communication between the first container  302  and the reductant dosing system  118 . Further, the first end  306  of the first conduit  304  is disposed in fluid communication with the first container  302  and the second end  308  of the first conduit  304  is disposed in fluid communication with the reductant dosing system  118   
     At step  504 , the vacuum is generated within the first container  302 . In one example, the vacuum may be generated within the first container  302  based on the activation of the vacuum pump  310 . Further, the first container  302  may contain the fluid therein. In another example, the vacuum may be generated within the first container  302  based on the draining of the fluid from the first container  302 , wherein the fluid may be drained based on the operation of the valve  314  disposed in fluid communication with the first container  302 . 
     In yet another example, the vacuum may be generated within the first container  302  based on the draining of the fluid from the first container  302  by siphoning. In such an example, the fluid communication may be provided between the first container  302  and the second container  318 . The second conduit  320  may provide the fluid communication between the first container  302  and the second container  318 . Further, the portion of the fluid may be directed, via the second conduit  320 , from the first container  302  towards the second container  318  for generating the vacuum within the first container  302 . 
     At step  506 , the residual reductant is removed from the one or more components of the reductant dosing system  118  based on the generation of the vacuum within the first container  302 . At step  508 , the residual reductant is introduced into the first container  302  by the first conduit  304 . Further, in some examples, the residual reductant may be diluted with water before disposal. 
     It may be desirable to perform one or more of the steps shown in  FIG.  5    in an order different from that depicted. Furthermore, various steps could be performed together. 
     While aspects of the present disclosure have been particularly shown and described with reference to the embodiments above, it will be understood by those skilled in the art that various additional embodiments may be contemplated by the modification of the disclosed machines, systems, and methods without departing from the spirit and scope of what is disclosed. Such embodiments should be understood to fall within the scope of the present disclosure as determined based upon the claims and any equivalents thereof.