Granted Patent
Utility
US 5,335,539 · App. 08/095,810
Onboard detection of oxygen sensor switch rate for determining air/fuel ratio control system failure
Inventors:
Michael Stephen Sweppy, James Michael Kerns
Patented Case
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Granted: Aug 9, 1994
Filed: Jul 22, 1993
Inventors
Michael Stephen Sweppy
James Michael Kerns
Assignee (at issue)
Ford Motor Company
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.