Spark ignition timing control system for internal combustion engine with fail safe system for cylinder pressure sensor
AssigneeNissan Motor Co., Ltd.
InventorMamoru Shinshi
Life of this patent
Estimating the term…
Abstract
A fail safe system for a cylinder pressure sensor is used for a spark ignition timing control system which calculates a physical quantity for combustion energy within the combustion chamber of an engine cylinder of an internal combustion engine and corrects the spark ignition timing on the basis of the physical quantity. The fail safe system sets a running average of a statistical dispersion of the physical quantity to a predetermined greater value when a specific driving condition, i.e. a high engine load and high engine speed condition is initially determined, and thereafter compares the running average with a predetermined value when the specific driving condition is detected again to detect abnormality of the cylinder pressure sensor.
Claims10
A fail safe system for a cylinder pressure sensor used for a spark ignition timing control system which calculates a physical quantity for combustion energy within the combustion chamber of an engine cylinder of an internal combustion engine and corrects the spark ignition timing on the basis of said physical quantity, said fail safe system comprising:
- first means for calculating a running average of a statistical dispersion of said physical quantity;
- second means for detecting a specific driving condition of said internal combustion engine;
- third means for setting said running average to be a first value so as to make said running average larger when said specific driving condition is initially detected;
- and
- fourth means for comparing said running average with a second value when said specific driving condition is detected, and for detecting abnormality of said cylinder pressure sensor.
A spark ignition timing correction system comprising:
- sensor means for monitoring fluctuation in pressure within the combustion chamber of an engine cylinder of an internal combustion engine and for producing a sensor signal indicative of said fluctuation;
- first means for calculating a physical quantity for combustion energy within the combustion chamber on the basis of said sensor signal;
- second means for calculating a deviation which is equal to a difference between said physical quantity and a running average thereof, and for comparing said deviation with a first value;
- third means for correcting the spark ignition timing so as to be retarded when said deviation is greater than said first value, and to be advanced when said deviation is less than said first value;
- fourth means for calculating a running average of said deviation;
- fifth means for detecting a specific driving condition of said internal combustion engine;
- sixth means for setting said running average to be a second value so as to make said running average larger when said specific driving condition is initially detected;
- and
- seventh means for comparing said running average with a third value while said specific driving condition is detected, and for detecting abnormality of said sensor means.
Dependencies are inferred from the claim text.