Intrusive EGR monitor for a hybrid vehicle
AssigneeFord Global Technologies, LLC
InventorsDouglas Raymond Martin, Richard Paul Taylor, Freeman Gates
Life of this patent
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Abstract
A system and method for controlling an exhaust gas recirculation (EGR) system in a hybrid vehicle using an intrusive monitor include adjusting EGR flow through an EGR valve based on an average pressure difference between pressure measured from a manifold absolute pressure (MAP) sensor and inferred pressure determined from mass air flow (MAF) into an intake of an engine when engine speed, throttle and camshaft timing position change is below a corresponding threshold. The measured pressure and inferred pressure are determined when the EGR valve is in a closed position and an open position.
Claims20
A method for controlling an EGR system in a hybrid vehicle, comprising:
- increasing EGR flow through an EGR valve responsive to a sum of a first difference between a first and a second measured MAP and a second difference between a first and a second inferred MAP being below a first threshold;
- and
- decreasing EGR flow through the EGR valve in response to the sum exceeding a second threshold different from the first threshold.
A method comprising:
- storing measured and inferred MAP values responsive to camshaft timing position change being below a corresponding threshold;
- storing a diagnostic code responsive to a sum of a difference between first and second measured MAP values and a second difference between first and second inferred MAP values being between first and second thresholds;
- and
- incrementing and decrementing an adaptive parameter to control increasing and decreasing of EGR flow, respectively, based on the sum relative to a third threshold and a fourth threshold different from the third threshold.
A hybrid vehicle, comprising:
- an engine;
- a MAP sensor coupled to an intake manifold of the engine;
- a MAF sensor coupled to an inlet of the intake manifold of the engine;
- an EGR duct coupled to the intake manifold of the engine and an exhaust manifold of the engine, the EGR duct having an EGR valve configured to recirculate exhaust gas from the exhaust manifold into the intake manifold of the engine;
- and
- a controller in communication with the engine, the MAP sensor, the MAF sensor and the EGR valve, the controller being configured to increase EGR flow through the EGR valve in response to a sum of a first difference between a first and a second measured MAP and a second difference between a first and a second inferred MAP being below a first threshold and to decrease EGR flow through the EGR valve in response to the sum of the first difference and the second difference exceeding a second threshold different from the first threshold.
Dependencies are inferred from the claim text.