Abstract: A method for compensating for variable cam timing of an internal combustion engine is provided. The method includes: a) providing a periodical crank pulse signal; b) providing a periodical cam pulse signal; c) determining a segment, wherein the internal combustion engine speed induces a volatile change upon Zphase values; d) dividing the segment into sub-segments; and e) calculating Zphase values of a plurality of points within the sub-segments.

Abstract: A system and method for determining a phase offset in a system having at least two rotating shafts moving in relation to each other is provided including a scheme, wherein two sets of registers having a first set of registers associated with the first rotating shaft, and the second set of registers associated with the second rotating shaft, providing at least one flag for directing or pointing at a particular register for storing values relating to the consecutive pulses; providing a controller for controlling the flag and the storage of values; determining a register among the set of registers shall store data; and pointing the flag to the register, thereby the information relating to phase shall not be lost or overwritten by using a single set of register for a single type of information.

Abstract: A method that provides increased flexibility to measure dynamic range of a rotating system is provided. The method includes the steps of: providing a first rotating member; providing a second rotating member suitably engaged to the first rotating member; providing a set of sensors disposed to sense variations in characteristics along a circumference of the first member and the second member respectively; providing a controller for receiving information sensed by the sensors; determining a rate of rotation of the rotating members; selectively using the sensed information thereby at different rate of rotation different amount of the sensed information is used.

Abstract: A method that provides increased flexibility to measure dynamic range of a rotating system is provided. The method includes the steps of: providing a first rotating member; providing a second rotating member suitably engaged to the first rotating member; providing a set of sensors disposed to sense variations in characteristics along a circumference of the first member and the second member respectively; providing a controller for receiving information sensed by the sensors; determining a rate of rotation of the rotating members; selectively using the sensed information thereby at different rate of rotation different amount of the sensed information is used.

Abstract: In a Variable Cam Timing (VCT) control system, there are conditions when the system must operate in an open-loop mode, and other situations where closed-loop operation is desired. A number of operating states is provided for VCT control system to switch between the states. A control methodology for switching between these two modes of operation, with minimal disturbances, is described. Further, during switching from open loop to closed loop, a scheme that impedes the impact upon the VCT system is provided.

Abstract: In a VCT system, a method uses a controller to automatically determine a state of a phaser based on an identifier. The identifier identifies a filtered signal of the crank shaft and cam shaft and uses the same to identify the phaser state. A reset signal is generated by the identifier to reset the VCT system, specifically to reset a control law whereby the unnecessary information retained by the VCT system is cleared. Therefore, the controller is able to promptly and accurately determine the phaser position and state.

Abstract: An engine with dependent intake cams requires a different method and formula to determine the phase of the intake cams. The exhaust camshaft drives the intake camshaft and so the intake cam position is dependent upon the exhaust cam position. The present invention provides a VCT cam timing system utilizing calculation of intake phase for dual dependent cams.

Abstract: A method that uses a dither signal for reducing hysteresis effect in a variable cam timing system is provided. The method includes the steps of: a) providing a dither signal having at least two switchable frequencies; b) determining the frequency characteristics of an engine speed; c) determining at least one frequency beating point in relation to a neighborhood of an engine crank RPM values; and d) changing the dither signal frequency when the engine is operating within the neighborhood of the engine crank RPM values. Thereby frequency beating effect is reduced.

Abstract: A method that uses a dither signal for reducing hysteresis effect in a variable cam timing system is provided. The method includes the steps of: a) providing a dither signal having at least two switchable frequencies; b) determining the frequency characteristics of an engine speed; c) determining at least one frequency beating point in relation to a neighborhood of an engine crank RPM values; and d) changing the dither signal frequency when the engine is operating within the neighborhood of the engine crank RPM values. Thereby frequency beating effect is reduced.

Abstract: In a VCT system, a method uses a controller to automatically determine a state of a phaser based on an identifier. The identifier identifies a filtered signal of the crank shaft and cam shaft and uses the same to identify the phaser state. A reset signal is generated by the identifier to reset the VCT system, specifically to reset a control law whereby the unnecessary information retained by the VCT system is cleared. Therefore, the controller is able to promptly and accurately determine the phaser position and state.

Abstract: In a Variable Cam Timing (VCT) control system, there are conditions when the system must operate in an open-loop mode, and other situations where closed-loop operation is desired. A number of operating states is provided for VCT control system to switch between the states. A control methodology for switching between these two modes of operation, with minimal disturbances, is described. Further, during switching from open loop to closed loop, a scheme that impedes the impact upon the VCT system is provided.

Abstract: An engine with dependent intake cams requires a different method and formula to determine the phase of the intake cams. The exhaust camshaft drives the intake camshaft and so the intake cam position is dependent upon the exhaust cam position. The present invention provides a VCT cam timing system utilizing calculation of intake phase for dual dependent cams.

Abstract: A method for compensating for variable cam timing of an internal combustion engine is provided. The method includes: a) providing a periodical crank pulse signal; b) providing a periodical cam pulse signal; c) determining a segment, wherein the internal combustion engine speed induces a volatile change upon Zphase values; d) dividing the segment into sub-segments; and e) calculating Zphase values of a plurality of points within the sub-segments.