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US 2016/0258376 A1Published application
Method and system for determining air-fuel ratio imbalance
AssigneeFord Global Technologies, LLC
InventorsHassene Jammoussi, Imad Hassan Makki, Michael I. Kluzner, Robert Roy Jentz
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Abstract
Methods and systems are presented for assessing the presence or absence of cylinder air-fuel ratio deviation that may result in air-fuel ratio imbalance between engine cylinders. In one example, the method may include assessing the presence or absence of air-fuel ratio errors based on deviation from an expected air-fuel ratio during a deceleration fuel shut-off event.
Claims20
A driveline operating method, comprising:
- during a deceleration fuel shut-off (DFSO) event, prohibiting fueling of one or more cylinders in response to a driveline being at a zero torque point, and fueling the one or more cylinders in response to the driveline not being at the zero torque point, each of the one or more cylinders fueled with a selected fuel pulse width, and
- indicating an air-fuel ratio variation for each of the one or more cylinders based on air-fuel deviation from a maximum lean air-fuel ratio during the DFSO.
A driveline operating method, comprising:
- deactivating all cylinders of an engine during deceleration fuel shut off;
- reactivating one or more cylinders of all the cylinders to determine air-fuel imbalance in the one or more cylinders;
- and
- not processing data for the one or more cylinders to determine air-fuel imbalance in the one or more cylinders in response to a torque converter impeller speed being within a predetermined speed of a torque converter turbine speed.
1 more element
A driveline operating method, comprising:
- after disablement all cylinders leading to a common exhaust passage of an engine:
- selectively individually fueling one or more of the disabled cylinders to combust a lean air-fuel mixture responsive to a driveline torque condition;
- and
- adjusting engine operation in response to a perturbation in exhaust air-fuel ratio from a maximum lean air-fuel ratio.
1 more element
Dependencies are inferred from the claim text.