Exhaust gas recirculation system fault detector
AssigneeFord Motor Company
InventorsMichael J. Cullen, Rogelio G. Samson, Alistair S. Teasdale, Richard L. Wanat
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Abstract
The method for determining a fault in an exhaust gas recirculation system includes comparing the measured exhaust gas flow of the EGR system to an expected exhaust gas recirculation flow. If the two are not the same the time period that the expected exhaust gas recirculation flow deviates from the measured exhaust gas recirculation flow by a calibrated EGR flow amount is determined. A fault condition in the EGR system is indicated if the duration of the deviation exceeds a predetermined amount of time.
Claims10
A method of determining a fault in an EGR system includes the steps of:
- comparing the measured exhaust gas flow through the EGR system to an expected EGR flow;
- determining the period of time that the expected flow of EGR deviates from the measured EGR flow by a calibrated EGR flow amount;
- and
- indicating a fault condition in the EGR system if the duration of the deviation exceeds a predetermined amount of time.
A method of determining and following operation of an EGR system including the steps of:
- determining EGR flow is between an upper and a lower limit of EGR flow magnitude;
- checking for the disconnection of a downstream hose;
- checking for disconnection of an upstream hose;
- checking for a restricted or plugged EGR valve;
- checking for an EGR valve stuck in an open position;
- checking for a restricted EGR metering orifice via a delta pressure;
- and
- checking for a restricted EGR metering orifice via oscillations in an EGR duty cycle.
Dependencies are inferred from the claim text.