Variable Camshaft Timing Assembly Single Actuation
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Solution Overview
Problem
Existing variable camshaft timing (VCT) technologies in internal combustion engines require two sources of actuation, increasing the axial length and complexity of the VCT assembly, which can be costly and inflexible in certain applications.
Innovation Solution
A VCT assembly with a single source of actuation, utilizing an independent VCT device with a rotating component and a dependent VCT device without direct rotation, where phase lugs move along sets of slots to control the angular positions of camshafts, achieving a dependent phase relationship and reducing axial length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two VCT devices are used to independently control angular position of concentric camshafts, then the angular position control capability is improved, but the axial length and device complexity increase
Solution Approach 1:
The patent combines two separate VCT devices into a single integrated VCT assembly that simultaneously controls both concentric camshafts. The first VCT device includes a rotor with slots that receive phase lugs from the second VCT device, merging the functions of two independent devices into one unified structure that reduces axial length while maintaining independent angular position control capability.
Solution Approach 2:
The patent implements a nested configuration where the second VCT device is positioned within the structural envelope of the first VCT device. The phase lugs of the second device are received within the slots of the first device's rotor, creating a nested arrangement that minimizes the overall axial length of the VCT assembly while preserving the independent control functionality of both camshafts.
2Adaptability or versatility
If two VCT devices are used to independently control angular position of concentric camshafts, then the angular position control capability is improved, but the device complexity and cost increase
Solution Approach 1:
The patent merges two separate VCT devices into a single integrated assembly, reducing the total number of components and reducing complexity. The first VCT device's rotor integrates the slot structure that receives and guides the phase lugs of the second device, creating a unified system with fewer discrete parts while maintaining the ability to independently control both camshaft angular positions.
Solution Approach 2:
The first VCT device's rotor serves multiple functions: it provides the primary actuation mechanism for the first camshaft while simultaneously serving as the structural framework that receives, guides, and actuates the phase lugs of the second VCT device. This multi-functionality reduces the overall device complexity by eliminating redundant components.
3Length of moving object
If a single VCT device is used to control both camshafts, then the axial length is reduced, but the phase relationship control flexibility is limited
Solution Approach 1:
The patent implements dynamic control of the phase relationship between the two camshafts through the interaction between the rotor slots and phase lugs. The non-circular slot profiles allow the phase lugs to move along predetermined paths, enabling dynamic adjustment of the phase relationship between camshafts while maintaining a compact single-device structure.
Solution Approach 2:
The patent utilizes non-circular slot profiles in the rotor to change the geometric parameters of the phase lugs' motion paths. By varying the slot geometry, the system can achieve different phase relationships between the camshafts, providing control flexibility equivalent to having two separate VCT devices while maintaining a reduced axial length.
Data Source
AI summary
A variable camshaft timing (VCT) assembly for controlling angular positions of concentric camshafts. The VCT assembly includes an independent VCT device and a dependent VCT device. The independent VCT device is hydraulically- or electrically-actuated. The independent VCT device is coupled with a first concentric camshaft and has a first component that rotates during phasing movements. The first component has a first set of slots therein. The dependent VCT device is coupled with a second concentric camshaft. The dependent VCT device has a second component that lacks rotation during phasing movements, and has multiple phase lugs. The second component has a second set of slots therein. The phase lugs are received in the first set of slots and are received in the second set of slots.