Integrated fuel catalyst monitor
AssigneeFord Global Technologies, LLC
InventorsBrent Edward Sealy, Jeffrey Scott Hepburn, Paul Chester Dara
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Abstract
A method is provided for monitoring an emission device coupled to an engine. In one example approach, the method comprises: following a deceleration fuel shut-off duration, indicating degradation of the emission device based on an amount of rich products required to cause a sensor to become richer than a threshold. The amount of rich products required may be correlated to an amount of oxygen stored in the emission device. The indication of emission device degradation may be further based on air mass and temperature during delivery of the required rich products.
Claims17
A method for monitoring an emission device coupled to an engine, comprising:
- following a deceleration fuel shut-off duration (DFSO), indicating degradation of the emission device based on an amount of rich products required to cause a sensor to become richer than a threshold, the indicating carried out when the DFSO duration is greater than a second threshold, the second threshold based on the sensor being lean at or before an end of the DFSO.
A system for monitoring an emission control device coupled to a combustion engine, comprising:
- an air-fuel sensor coupled downstream of a volume of catalyst material of the emission control device;
- a control system having a computer storage medium with instructions encoded thereon, the instructions comprising:
- instructions to initiate a deceleration fuel shut-off based on an engine operating condition;
- following the deceleration fuel shut-off, instructions to begin fueling in response to a driver tip-in;
- following the driver tip-in, instructions to indicate degradation of the emission control device based on a total amount of rich products delivered from the beginning of the fueling up to a switch of the air-fuel sensor from lean to reading rich.
A method for an engine having a catalytic device and an air-fuel sensor downstream of the catalytic device, comprising:
- performing a fuel shut-off event while the engine rotates and pumps air through the catalytic device, then;
- re-initiating fuel injection;
- and
- if the fuel shut-off event continued sufficiently long for the air-fuel sensor to indicate lean, indicating device degradation based on an amount of rich exhaust products delivered from the fuel injection initiation to a lean-rich sensor transition.
Dependencies are inferred from the claim text.