Methods and systems for open loop and closed loop control of an exhaust gas recirculation system
AssigneeFord Global Technologies, LLC
InventorsFreeman Carter Gates, Kirk Pulay, Stephen George Russ
Life of this patent
Estimating the term…
Abstract
Methods and systems are provided for estimating exhaust gas recirculation (EGR) flow in an engine including an EGR system. In one example, a method may include operating the EGR system in an open loop feed forward mode based on an intake carbon di oxide sensor output above a threshold engine load and/or when a manifold absolute pressure (MAP) is above a threshold pressure, and operating the EGR system in a closed loop feedback mode based on a differential pressure sensor output when the engine load decreases below the threshold load and/or when the MAP decreases below the threshold pressure.
Claims15
A method for an engine, comprising:
- estimating an exhaust gas recirculation (EGR) mass flow based on a differential pressure sensor output when an engine load is below a threshold;
- estimating the EGR mass flow based on an intake carbon dioxide sensor output when the engine load is above the threshold and independent of the differential pressure sensor output;
- and
- adjusting a spark timing based on the estimated EGR mass flow.
10-15. (canceled)
A method for an engine, comprising:
- during a first condition, operating an EGR valve based on an error between a desired DP sensor output and a measured DP sensor output, and adjusting spark timing based on the measured DP sensor output;
- and
- during a second condition, operating the EGR valve independent of the DP sensor output, and adjusting spark timing based on an intake carbon dioxide sensor voltage.
Dependencies are inferred from the claim text.