Method of diagnosing several systems and components by cycling the EGR valve
First Claim
1. A method to operate an electronic controlled internal combustion engine having an electronic controller with memory and equipped with an Exhaust Gas Recirculation (EGR) system, said engine connectable with an exhaust aftertreatment system, comprising:
- a) operating said engine to maintain a predetermined operating status for a predetermined period of time;
b) determining whether said engine operating status is stable for at least one engine operating parameter for a predetermined period of time;
c) cycling said EGR system valve between a first position for a predetermined period of time and a second position for a predetermined period of time; and
d) determining a change in said engine operating parameter to determine whether an engine component or system is malfunctioning;
wherein NOx emission values from NOx sensors are compared and if engine out NOx and exhaust out NOx increase when the EGR valve is open and decrease when the EGR valve is closed and engine out NOx and exhaust out NOx differ by a predetermined amount within a predetermined period of time, said NOx sensors are within operating specifications.
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Accused Products
Abstract
A method to operate an electronic controlled internal combustion engine to perform on board NOx emissions level diagnostics. In one embodiment, the method may include operating the engine to maintain a predetermined temperature for a predetermined period of time, determining whether the engine operating status is stable for one of cruise control, idle engine speed, engine torque, or high idle regeneration for a predetermined period of time, cycling the EGR valve between a first position for a predetermined period of time and then in a second position for a predetermined period of time, a determining a change in engine out NOx levels to determine whether an engine component or system is malfunctioning.
42 Citations
23 Claims
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1. A method to operate an electronic controlled internal combustion engine having an electronic controller with memory and equipped with an Exhaust Gas Recirculation (EGR) system, said engine connectable with an exhaust aftertreatment system, comprising:
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a) operating said engine to maintain a predetermined operating status for a predetermined period of time; b) determining whether said engine operating status is stable for at least one engine operating parameter for a predetermined period of time; c) cycling said EGR system valve between a first position for a predetermined period of time and a second position for a predetermined period of time; and d) determining a change in said engine operating parameter to determine whether an engine component or system is malfunctioning; wherein NOx emission values from NOx sensors are compared and if engine out NOx and exhaust out NOx increase when the EGR valve is open and decrease when the EGR valve is closed and engine out NOx and exhaust out NOx differ by a predetermined amount within a predetermined period of time, said NOx sensors are within operating specifications. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A controller for intrusive diagnostic testing configured to:
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a) operate an engine to maintain a predetermined temperature for a predetermined period of time; b) determine engine operating status for at least one engine operating parameter for a predetermined period of time; c) cycle an EGR valve between a first position for a predetermined period of time and a second position for a predetermined period of time; and d) determine a change in at least one of engine out NOx and exhaust out NOx to determine whether a NOx reductant system malfunctions.
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13. A method to operate an electronic controlled internal combustion engine having an electronic controller with memory and equipped with an Exhaust Gas Recirculation (EGR) system, said engine connectable with an exhaust aftertreatment system, comprising:
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a) operating said engine to maintain a predetermined operating status for a predetermined period of time; b) determining whether said engine operating status is stable for at least one engine operating parameter for a predetermined period of time; c) cycling said EGR system valve between a first position for a predetermined period of time and a second position for a predetermined period of time; and d) determining a change in said engine operating parameter to determine whether an engine component or system is malfunctioning; wherein NOx emission values are compared and if engine out NOx and exhaust out NOx increase when the EGR valve is open and decrease when the EGR valve is closed and engine out NOx and exhaust out NOx differ by a predetermined amount within a predetermined period of time, a NOx reductant system is within operating specifications. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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Specification