Patent ID: 11965472
Assignee: FORD GLOBAL TECHNOLOGIES, LLC
Field: Engines, pumps, turbines (Mechanical engineering)
Classification: CPC F | IPC F

Claim 14:
15. A vehicle, comprising:
a multi-cylinder internal combustion engine having a sensor associated with a group of cylinders; and
a vehicle controller programmed to:
select a subset of cylinders containing less than all of the group of cylinders for air-fuel ratio monitoring, the subset including cylinders previously identified as having reliable air-fuel ratio determinations based on signals from the sensor for a current engine speed-load operating region;
repeat the selecting of subsets of cylinders for different engine speed-load operating regions until all of the cylinders of the engine have a predetermined number of air-fuel ratio determinations;
generate an air-fuel ratio imbalance signal in response to a difference among the air-fuel ratio determinations for different cylinders exceeding a corresponding threshold; and
control air-fuel ratio of at least one of the group of cylinders responsive to the air-fuel ratio imbalance signal.