Method of adaptively controlling a motor vehicle engine system
AssigneeFord Global Technologies, LLC
InventorsMark Ustel, Mohammad Farid
Life of this patent
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Abstract
A method is disclosed for adaptively controlling an engine system of a motor vehicle comprising the steps of evaluating the outputs from angular position sensors associated with inlet and exhaust camshafts of an engine of the engine system to establish whether differences between the currently measured positions and previously saved positions are the result of elongation of an endless drive used to drive the camshafts or due to some other reason. If it is confirmed that the differences are due to elongation of the endless drive then the measured values of angular position are used in the control of a number of engine functions.
Claims20
A method of adaptively controlling a motor vehicle engine system comprising an engine having a crankshaft, first and second camshafts driven by an endless drive system including an endless drive from a crankshaft of the engine and an electronic controller, wherein the method comprises:
- measuring an angular position for one of the first and second camshafts when the crankshaft is in a reference position and using the measured angular position to produce a value of change in angular position for the one camshaft;
- measuring an angular position for the other camshaft of the first and second camshafts when the crankshaft is in the same reference position and using the measured angular position to produce a value of change in angular position for the other camshaft;
- establishing whether any change in angular position for one camshaft is in a retarded direction the same as a corresponding angular change for the other camshaft;
- establishing whether any changes in angular position of the camshafts are gradual changes;
- establishing whether a ratio of change of angular position of one camshaft with respect to the other camshaft is substantially equal to a predefined fixed ratio based upon a geometry of the endless drive system;
- and
- if the results of the establishing steps indicate that any change in angular position is in the same retarded direction for both camshafts and any changes in angular position are gradual changes and the ratio of angular change of one camshaft with respect to the other camshaft is substantially equal to a predefined fixed ratio based upon the geometry of the endless drive system, the method further comprises confirming that the current change in angular position of the first and second camshafts is a result of elongation of the endless drive, and using the measured angular positions of the first and second camshafts in the control of one or more operational functions of the engine.
A motor vehicle engine system comprising an engine having first and second camshafts driven by an endless drive system including an endless drive from a crankshaft of the engine, a crankshaft sensor to sense a rotational position of the crankshaft, and first and second camshaft sensors to sense rotational positions of the first and second camshafts respectively when the crankshaft is in a reference position;
- and an electronic controller to process outputs from the crankshaft sensor and the two camshaft sensors wherein the electronic controller is operable to:
- use the outputs from the first and second camshaft sensors to establish whether any change in angular position for one camshaft is in a retarded direction the same as a corresponding angular change for the other camshaft;
- use the outputs from the first and second camshaft sensors to establish whether any changes in angular position of the camshafts are gradual changes;
- use the outputs from the first and second camshaft sensors to establish whether a ratio of change of angular position of one camshaft with respect to the other camshaft is substantially equal to a predefined fixed ratio based upon a geometry of the endless drive system;
- and
- if the results of the use steps indicate that any change in angular position is in the same retarded direction for both camshafts and any changes in angular position are gradual changes and the ratio of angular change of one camshaft with respect to the other camshaft is substantially equal to a predefined fixed ratio based upon the geometry of the endless drive system, the electronic controller is operable to confirm that a current change in angular position of the first and second camshafts is the result of elongation of the endless drive, and is further operable to use the measured angular positions of the first and second camshafts in the control of one or more operational functions of the engine.
Dependencies are inferred from the claim text.