Patent ID: 8649961
Filing Date: 2014-02-11
Classification: F02D,F02M

Abstract:
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.