The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 28, 1993
Filed:
Nov. 25, 1992
Peter J Grutter, Plymouth, MI (US);
Gerald G Stock, Whitmore Lake, MI (US);
Ford Motor Company, Dearborn, MI (US);
Abstract
Apparatus and method are disclosed for monitoring catalytic converter efficiency in treating exhaust gas from an internal combustion engine having fuel control means for controlling the air to fuel ratio at which fuel is supplied to the engine in response to a fuel flow control signal. During a normal operation mode, the control signal means generates the fuel flow control signal based at least in part on output signals from first and second EGO sensors exposed to the exhaust gas upstream and downstream, respectively, of the catalytic converter. The normal operation mode is periodically interrupted by a test operation mode, preferably initiated during substantially steady state operation of the engine, during which the engine is controlled in response to the output signal from the first EGO sensor without the signal from the second EGO sensor. Air to fuel ratio perturbations about a mean value corresponding to stoichiometry are introduced, comprising an initial lean interval of air to fuel ratio higher than stoichiometry, typically for about 5 seconds, followed by a series of rich intervals alternating with lean intervals. An efficiency value for the catalytic converter corresponding to its emissions treatment efficiency is determined based on the number of perturbations detected by the upstream EGO sensor versus the number detected by the downstream EGO sensor.