Cam Phaser Control via Electronic Hydraulic Actuation
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Solution Overview
Problem
Current mechanical cam phasing systems in internal combustion engines are unable to independently control the relationship between the camshaft and crankshaft based on cam torque pulse magnitude and direction, leading to overshooting or undershooting, and require fast and continuous control to achieve desired rotation, which results in wear and inefficiency.
Innovation Solution
A cam phasing system that includes a sprocket hub, cradle rotor, spider rotor, and locking assemblies, allowing the spider rotor to rotate relative to the sprocket hub and cradle rotor, with an actuation mechanism to apply axial displacement and control the rotational relationship between the camshaft and crankshaft, independent of engine speed and cam torque pulses, by using helical features and locking mechanisms to lock and unlock positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If mechanical cam phasing systems use cam torque pulses to rotate the phaser, then the phaser can rotate in the direction of the torque pulse, but the speed and stop position cannot be controlled
Solution Approach 1:
The patent replaces the purely mechanical cam torque pulse-driven system with an electronically controlled hydraulic actuation system. The electronic controller independently manages phaser rotation speed and stop position through hydraulic pressure control, eliminating the dependency on cam torque pulse characteristics and enabling precise positional control.
Solution Approach 2:
The patent changes the control parameter from passive mechanical torque pulse response to active electronic-hydraulic pressure control. By using an electronic controller to regulate hydraulic fluid delivery to the actuator, the system can independently adjust phaser rotation speed and stop position regardless of cam torque pulse variations.
2Manufacturing precision
If mechanical cam phasing systems rely on cam torque pulses, then the system structure is simple, but the phaser overshoots or undershoots the desired rotation amount
Solution Approach 1:
The patent replaces the imprecise mechanical cam torque pulse system with an electronically controlled hydraulic system. The electronic controller provides precise control over phaser rotation by regulating hydraulic pressure, eliminating overshoot and undershoot issues while maintaining manageable system complexity through integrated electronic-hydraulic architecture.
Solution Approach 2:
The patent implements electronic control with the ability to monitor and adjust phaser position in real-time. The electronic controller can detect when the phaser reaches the desired position and adjust hydraulic pressure accordingly, providing feedback control that prevents overshoot and ensures precise stop position.
3Reliability
If mechanical cam phasing systems are cycled continuously to maintain position, then position control is achieved, but wear increases and efficiency decreases
Solution Approach 1:
The patent uses periodic hydraulic actuation only when phaser adjustment is needed, rather than continuous mechanical cycling. The electronic controller activates the hydraulic actuator in discrete cycles to achieve the desired position, then maintains position without continuous operation, reducing wear and energy consumption while preserving position control reliability.
Solution Approach 2:
The patent enables the phaser system to maintain its position without continuous external intervention. Once the desired position is achieved through electronic-hydraulic actuation, the system holds position independently without requiring continuous cycling, reducing mechanical wear and energy consumption while maintaining positioning accuracy.
Data Source
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Figure 2
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AI summary
Systems and methods for varying a rotational relationship between a cam shaft and a crank shaft on an internal combustion engine (i.e., cam phasing) are provided. In particular, systems and methods are provided that facilitates a rotary position of a first component to be accurately controlled with a mechanism causing a second component, which can be coupled to the cam shaft or crank shaft, to follow the rotary position of the first component.