Method for maintaining clean spark plugs in a variable displacement engine
AssigneeFord Motor Company
InventorsDavid K. Bidner, Glenn A. Zimlich, Daniel V. Orzel
Life of this patent
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Abstract
A method for maintaining clean spark plugs in a variable displacement engine in which at least one group of cylinders is disabled in response to the engine load being less than a predetermined value. A first timer determines the maximum period that the engine may be operated with the first group of cylinders being disabled. A second timer controls the period of time the previously deactivated cylinders need to be reactivated to clean the spark plugs, after being deactivated for the maximum period of time.
Claims17
A method for maintaining clean spark plugs in a variable displacement, multiple cylinder engine, comprising:
- generating a load signal in response to at least one of the operational parameter of the variable displacement engine;
- generating a light load signal in response to said load signal being less than at least a first predetermined value;
- terminating the fuel delivery and the energizing of the spark plugs for at least a first group of cylinders to disable said first group of cylinders in response to said light load signal;
- detecting when said at least first group of cylinders has been disabled for a first period of time to re-enable said at least first group of cylinders for a second period of time much shorter than said first period of time, said second period of time selected to be sufficient to clean said spark plugs;
- and
- repeating said step of terminating in response to the expiration of said second period of time.
A control for maintaining clean spark plugs in a variable displacement engine having a plurality of cylinders comprising:
- a load sensor responsive to the operational parameters of the engine to generate an engine load signal;
- a first comparator for generating a light load signal in response to said engine load signal being less than a predetermined value;
- means for terminating fuel delivery to and for terminating the energizing of the spark plugs to disable a first group of cylinders of the plurality of cylinders to disable said first group of cylinders in response to said light load signal to reduce the displacement of the variable displacement engine;
- a first timer enabled by said light load signal to measure the time said first group of cylinders are disabled;
- and
- a second timer, enabled by said first timer after a first predetermined amount of time, to deactivate said means for terminating and re-enable said first group of cylinders for a second period of time much shorter than said first period of time, said second period of time selected to clean the spark plugs.
Dependencies are inferred from the claim text.