Exhaust gas aftertreatment bypass system and methods

Abstract

A method for protecting an exhaust aftertreatment system of an internal combustion engine from deterioration by selectively diverting exhaust gasses from the engine away from a component of the exhaust aftertreatment system includes assessing a status of an operating condition associated with a physical condition of the component of the internal combustion engine. The status of the operating condition is compared with a threshold value that corresponds with deterioration of the physical condition of the component. A valve upstream of the component is moved to a first position to open a bypass fluid path directing exhaust gasses around the component when the status of the operating condition meets the threshold value to reduce deterioration of the component. The valve is moved to a second position to close the bypass fluid path thereby directing exhaust gasses to the component when the status of the operating condition does not meet the threshold.

What is claimed is: 
     
         1 . A method for protecting an exhaust aftertreatment system of an internal combustion engine from deterioration by selectively diverting exhaust gasses from the engine away from a component of the exhaust aftertreatment system, comprising:
 assessing a status of an operating condition associated with a physical condition of the component of the internal combustion engine;   comparing the status of the operating condition with a threshold value that corresponds with deterioration of the physical condition of the component;   moving a valve upstream of the component to a first position to open a bypass fluid path directing exhaust gasses around the component when the status of the operating condition meets the threshold value to reduce deterioration of the component; and   moving the valve to a second position to close the bypass fluid path thereby directing exhaust gasses to the component when the status of the operating condition does not meet the threshold value.   
     
     
         2 . The method of  claim 1 , wherein the operating condition includes a temperature of the exhaust gasses and the threshold value is an upper temperature limit above which the component produces harmful byproducts. 
     
     
         3 . The method of  claim 1 , wherein the operating condition includes a geographical location of the internal combustion engine and the threshold value includes geographical locations that do not require emissions controls for internal combustion engines. 
     
     
         4 . The method of  claim 1 , wherein the operating condition includes a chemical formulation of fuel used by the internal combustion engine and the threshold value includes chemicals that deteriorate the component. 
     
     
         5 . The method of  claim 4 , wherein the chemicals that deteriorate the component include sulfur. 
     
     
         6 . The method of  claim 1 , further comprising:
 overriding the step of moving the valve to the first position based on the threshold comparison by manually moving the valve to the second position to close the first fluid path and open the second fluid path to bypass the exhaust aftertreatment device.   
     
     
         7 . The method of  claim 1 , wherein the component is selected from the group consisting of: a selective catalytic reducer (SCR), an SCR coated filter, a diesel oxidation catalyst (DOC), a diesel particulate filter (DPF), and combinations thereof. 
     
     
         8 . A method for protecting an exhaust aftertreatment system of an internal combustion engine from deterioration by selectively diverting exhaust gasses from the engine away from a selective catalyst reducer (SCR) component of the exhaust aftertreatment system, comprising:
 assessing a status of an operating condition associated with a physical condition of the SCR component of the internal combustion engine;   comparing the status of the operating condition with a threshold value that corresponds with deterioration of the physical condition of the SCR component, the operation condition and threshold value including at least one of:
 a temperature of the exhaust gasses compared to a higher temperature threshold of the exhaust gasses above which the SCR component produces harmful byproducts, 
 fuel chemistry compared to an upper threshold limit of sulfur content above which the sulfur deteriorates the SCR component, or 
 a geographical position of the internal combustion engine compared to geographical locations that do not require emissions controls for internal combustion engines; 
   moving a valve upstream of the component to a first position to open a bypass fluid path directing exhaust gasses around the component when the status of the operating condition meets the threshold value to reduce deterioration of the SCR component; and   moving the valve to a second position to close the bypass fluid path thereby directing exhaust gasses to the SCR component when the status of the operating condition does not meet the threshold value.   
     
     
         9 . An apparatus for bypassing an exhaust aftertreatment device of an internal combustion engine to protect a selective catalytic reducer (SCR) component of the exhaust aftertreatment device from deterioration, the apparatus comprising:
 a flow control valve operable to open and close a bypass fluid path wherein exhaust gasses from the engine bypass the exhaust after treatment device when the valve is in the open position and the exhaust gasses flow through the exhaust aftertreatment device when the valve is in the closed position;   a sampling module that samples an operating condition of the internal combustion engine that is associated with a physical condition of the SCR component;   a comparison module that compares the operating condition with a threshold value that corresponds with deterioration of the physical condition of the SCR component; and   a control module that operates the flow control valve to open the bypass fluid path if the operating condition does not meet the threshold condition and to close the bypass fluid path if the operating condition meets the threshold condition.   
     
     
         10 . The apparatus of  claim 9 , wherein the sampling module samples a temperature of the exhaust gasses and the comparison module compares the temperature of the exhaust gasses to an upper temperature limit above which the SCR component produces harmful oxidation byproducts. 
     
     
         11 . The apparatus of  claim 9 , wherein the sampling module samples a geographical location of the internal combustion engine and the threshold value includes geographical locations that do not require emissions controls for internal combustion engines. 
     
     
         12 . The apparatus of  claim 9 , wherein the sampling module samples a chemical formulation of fuel used by the internal combustion engine and the threshold value includes chemicals that deteriorate the component. 
     
     
         13 . The apparatus of  claim 12 , wherein the chemicals that deteriorate the component include sulfur. 
     
     
         14 . The apparatus of  claim 9 , further comprising:
 a user interface associated with the control module configured to accept user input to override the control module control of the flow control valve and manually open the valve to the bypass fluid path to bypass the exhaust aftertreatment device.   
     
     
         15 . An internal combustion engine system, comprising:
 an internal combustion engine;   an exhaust aftertreatment system including a selective catalyst reducer (SCR) component in exhaust receiving communication with the internal combustion engine; and   a bypass system operatively associated with the exhaust aftertreatment system operable to bypass the SCR component when an operating condition of the internal combustion engine that corresponds with deterioration of a physical condition of the SCR component is detected.   
     
     
         16 . The system of  claim 15 , the bypass system further comprising:
 a flow control valve operable to open and close a bypass fluid path wherein exhaust gasses from the engine bypass the exhaust after treatment device when the valve is in the open position and the exhaust gasses flow through the exhaust aftertreatment device when the valve is in the closed position; and   a controller that determines whether the flow control valve is open to the bypass fluid path by sampling the operating condition of the internal combustion engine that is associated with the physical condition of the SCR component and comparing the sample of the operating condition with a threshold value that corresponds with deterioration of the physical condition of the SCR component.   
     
     
         17 . The system of  claim 16 , wherein the operating condition and threshold value include at least one of:
 a temperature of the exhaust gasses compared to a higher temperature threshold of the exhaust gasses above which the SCR component produces harmful byproducts;   fuel chemistry compared to an upper threshold limit of sulfur content above which the sulfur deteriorates the SCR; or   a geographical position of the internal combustion engine compared to geographical locations that do not require emissions controls for internal combustion engines.