Exhaust gas recirculation control system
AssigneeFord Global Technologies, LLC
InventorsAlexander Y. Gopp, Shailesh Patel
Life of this patent
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Abstract
An EGR control system provides on-line adaptation of the EGR valve Start to Open value during normal vehicle operations. The adaptive logic determines whether the valve position output signal reaches a predetermined minimum output signal value within a desired predetermined time window defined by upper and lower time values. If outside the window, the initial duty cycle value applied to the EGR valve is increased or decreased as appropriate to force the output signal to reach the minimum value within or at the boundaries of the time window.
Claims10
A method of adaptively adjusting a controller start to open calibration value in an exhaust gas recirculation (EGR) control system comprising a sequence of the following steps:
- activating EGR control with a signal including an initial duty cycle value in response to an input signal from an engine control system;
- comparing an output signal representing EGR valve output to a predetermined signal threshold;
- adjusting said initial duty cycle value if following activation, said output signal reaches said threshold before a predetermined lower time interval has expired or after a predetermined upper time interval has expired.
A method of adaptively adjusting a controller start to open calibration value in an exhaust gas recirculation control system comprising a sequence of the following steps:
- activating EGR control with a signal including an initial duty cycle value DC.sub.-- INIT in response to an input signal from an engine control system;
- comparing an output signal OUT representing EGR valve position to a predetermined signal threshold OUT.sub.-- MIN;
- increasing the value DC-INIT by an amount dDC.sub.-- INIT if, following activation, the signal OUT reaches OUT.sub.-- MIN after closure of a time window having an upper limit T2 and a lower limit T1;
- and
- decreasing the value DC-INIT by said amount dDC.sub.-- INIT if, following activation, said signal OUT is equal to or greater than said threshold prior to the opening of said time window.
An exhaust gas recirculation (EGR) control system for adaptively adjusting a controller start to open calibration value, comprising:
- means responsive to an input signal from an engine control system for activating EGR control with a signal including an initial duty cycle;
- means for comparing an output signal representing EGR valve position to a predetermined signal threshold;
- and
- means for adjusting said initial duty cycle value unless said output signal reaches said threshold within upper and lower time intervals following activation.
Dependencies are inferred from the claim text.