Variable displacement engine diagnostics
AssigneeFord Global Technologies, LLC
InventorsJeffrey Allen Doering, John Eric Rollinger
Life of this patent
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Abstract
Methods and systems are provided for monitoring cylinder valve deactivation in an engine operating with a plurality of cylinder valves. One example method comprises indicating valve degradation based on an indication of manifold pressure over a plurality of immediately successive induction events of the engine, the indication responsive to increases and decreases in the indication of manifold pressure correlated to the induction events of engine cylinders and further correlated to whether cylinders are commanded to be activated or deactivated.
Claims16
A method for an engine with cylinder valve deactivation and a plurality of cylinder valves, comprising:
- commanding a plurality of cylinder valves of a cylinder to deactivate or reactivate;
- and
- indicating valve degradation based manifold pressure over a plurality of immediately successive induction events of the engine, said indication responsive to increases and decreases in the manifold pressure correlated to the induction events of engine cylinders and further correlated to whether cylinders are commanded to be activated or deactivated, wherein the plurality of immediately successive induction events of the engine includes induction events for cylinders immediately preceding and/or cylinders immediately succeeding a monitored cylinder, wherein the indication of manifold pressure over a plurality of immediately successive induction events includes a statistically determined manifold pressure for the plurality of immediately successive induction events.
A method for an engine with cylinder valve deactivation, comprising:
- indicating valve degradation in a monitored cylinder by comparing:
- a manifold pressure change during an induction event of the monitored cylinder and a minimum of manifold pressure changes for cylinders firing before and after the monitored cylinder when commanding the monitored cylinder to deactivate, and
- the manifold pressure change and a maximum of the manifold pressure changes when commanding the monitored cylinder to activate.
A system, comprising:
- an engine having a plurality of cylinders, each cylinder with a plurality of cylinder valves;
- a deactivation mechanism for deactivating at least one cylinder valve;
- a variable cam timing mechanism for adjusting a timing of at least one cylinder valve;
- a sensor providing information indicative of manifold pressure;
- and
- a control system configured to receive indication of manifold pressure over a plurality of immediately successive induction events of the engine, said indication responsive to increases and decreases in the indication of manifold pressure correlated to the induction events, said increases and decreases identified during selected windows of operation, the windows varying with variation of the variable cam timing mechanism, and to indicate valve degradation based on said indication of manifold pressure and further based on whether cylinders are commanded to be activated or deactivated, said indication of valve degradation differentiating between intake valve degradation and exhaust valve degradation.
Dependencies are inferred from the claim text.