Cam phaser control
First Claim
1. A method of controlling the phase of an adjustable phase camshaft relative to a crankshaft of an engine, wherein the adjustable phase camshaft is utilized to actuate at least one engine valve, the method comprising utilizing knowledge of at least one of:
- (i) firing events in a skip fire firing sequence, and(ii) dynamically determined valve actuation events,in the control of a cam phase adjustment device in a manner that maintains the phase of the adjustable phase camshaft more stable at a consistent commanded camshaft position through transitory variations in torque applied to the adjustable phase camshaft by the actuation of the at least one engine valve than would occur without such control.
1 Assignment
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Accused Products
Abstract
Arrangements for stabilizing valve timing adjustment mechanisms such as cam phasers during operation of an engine are described. The described approaches are particularly well suited for use during skip fire control, although they may be used advantageously in other applications as well. In general, the phase of an adjustable phase camshaft is controlled relative to a crankshaft of an engine. In one aspect, at least one of (i) firing events in a skip fire firing sequence, and (ii) dynamically determined valve actuation events are used in the control of the camshaft phase during operation of the engine. In some embodiments, hydraulic pressure within a cam phaser is varied in a manner that maintains the phase of the camshaft substantially more stable through transitory variations in torque applied to the camshaft by the actuation of the valves than would occur without the variations in hydraulic pressure.
83 Citations
15 Claims
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1. A method of controlling the phase of an adjustable phase camshaft relative to a crankshaft of an engine, wherein the adjustable phase camshaft is utilized to actuate at least one engine valve, the method comprising utilizing knowledge of at least one of:
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(i) firing events in a skip fire firing sequence, and (ii) dynamically determined valve actuation events, in the control of a cam phase adjustment device in a manner that maintains the phase of the adjustable phase camshaft more stable at a consistent commanded camshaft position through transitory variations in torque applied to the adjustable phase camshaft by the actuation of the at least one engine valve than would occur without such control. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method of dynamically tracking reactionary torque applied to a camshaft during operation of an engine, the method comprising:
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receiving an indication of at least one of (i) a skip fire firing sequence, and (ii) a sequence of engine events that include at least valve actuation events; and dynamically determining an estimated reactionary torque applied to the camshaft during operation of the engine, wherein the determined reactionary torque tracks and accounts for transitory torque variations imparted by the actuation of the at least one engine valve actuated by the camshaft during operation of the engine. - View Dependent Claims (8, 9, 10, 11)
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12. A cam phaser control module for controlling hydraulic pressure within a cam phaser cavity in order to control a phase of a camshaft during operation of an engine, the cam phaser control module comprising:
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a camshaft torque calculator arranged to dynamically determine the torque applied to a camshaft during operation of the engine; and a phaser solenoid duty cycle controller that modulates the hydraulic pressure within the cam phaser cavity over the course of an engine cycle based at least in part upon the dynamically determined torque in a manner that counteracts transient torque variations caused by actuation of valves that occur during operation of the engine over the course of the engine cycle. - View Dependent Claims (13, 14, 15)
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Specification