Concentric Camshaft Timing Assembly With Dependent VCT Linkage
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Solution Overview
Problem
The existing variable camshaft timing (VCT) assemblies for internal combustion engines are cumbersome due to the need for two independently controlled camshafts, which increases axial length, complexity, and cost.
Innovation Solution
A VCT assembly design featuring an independent VCT device that controls the angular position of a first camshaft relative to the crankshaft, with one or more dependent VCT devices mechanically linking the output to a second camshaft, utilizing a planetary gear system to pivot and engage a ring gear, allowing the angular position of the second camshaft to be adjusted based on the motion of the independent VCT device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If two independent VCT devices are used to control the angular position of concentric camshafts, then the angular position control is achieved, but the axial length of the VCT assembly increases
Solution Approach 1:
The patent combines two independent VCT devices into a single integrated assembly where one VCT device controls the angular position of the first camshaft relative to the crankshaft, and a second VCT device controls the angular position of the second camshaft relative to the first camshaft. This merging reduces the overall axial length while maintaining independent control capability through shared housing and synchronized operation
Solution Approach 2:
The patent implements a nested configuration where the second VCT device is positioned within or alongside the first VCT device, with both devices sharing common housing structures and mounting features. The concentric camshafts themselves provide a nested arrangement, allowing the VCT devices to be compactly arranged along the axial direction
2Ease of operation
If two independent VCT devices are used to control the angular position of concentric camshafts, then the angular position control is achieved, but the complexity of the VCT assembly increases
Solution Approach 1:
The patent merges two VCT devices into a single integrated assembly with shared housing, mounting features, and synchronized control mechanisms. This reduces the number of separate components and simplifies the overall assembly structure while maintaining the capability to independently control both camshafts' angular positions
Solution Approach 2:
The integrated VCT assembly performs multiple functions within a single structure: it controls the angular position of the first camshaft relative to the crankshaft, controls the angular position of the second camshaft relative to the first camshaft, and provides synchronized operation of both devices through shared housing and mounting features
3Ease of operation
If two independent VCT devices are used to control the angular position of concentric camshafts, then the angular position control is achieved, but the cost of the VCT assembly increases
Solution Approach 1:
The patent combines two VCT devices into a single manufactured assembly with shared housing and common components. This integration reduces the total number of parts that need to be manufactured, inventory managed, and assembled, thereby reducing overall manufacturing cost while maintaining dual camshaft control capability
Data Source
AI summary
A variable camshaft timing (VCT) assembly for controlling the angular position of concentric camshafts includes an independent VCT device that is configured to couple with a first concentric camshaft and change an angular position of the first concentric camshaft relative to an angular position of a crankshaft; and one or more dependent VCT devices mechanically linking an output of the independent VCT device with a second concentric camshaft, wherein the dependent VCT device(s) change(s) an angular position of the second concentric camshaft relative to the angular position of the first concentric camshaft based on angular movement of the output of the independent VCT device.