Adjustable Driven Cam for Variable Valve Lift
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Solution Overview
Problem
Conventional continuously variable valve actuation (CVVA) systems are complex and costly due to the need for multiple components to transmit force from the driving cam to the valve, making it difficult to simultaneously vary the lift time and distance of the valve effectively.
Innovation Solution
A simplified CVVA system using a driven cam with an adjustable rotational axis and cam face sections (high lift and low lift) that directly transmits force to the valve, allowing for variable lift time and distance without a separate rocker arm or variable cam, utilizing an actuator to limit the cam face to specific sections and a slide stub for precise adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple components (swing arm, variable arm, driving arm, rocker arm) are used to transmit force from driving cam to valve, then the lift time and distance can be regulated, but the configuration becomes complicated and manufacturing costs increase
Solution Approach 1:
The patent merges multiple separate components (swing arm, variable arm, driving arm, rocker arm) into a single integrated driven cam structure. The driven cam incorporates the cam face, the force transmission path, and the valve actuation function all in one component, eliminating the need for separate arms and rocker mechanisms while maintaining the ability to regulate valve lift time and distance.
Solution Approach 2:
The driven cam serves multiple functions simultaneously: it transmits force from the driving cam, regulates valve lift time through its rotational movement, controls valve lift distance through the cam face geometry, and directly actuates the valve. This multi-functional design replaces several specialized components with a single universal element.
2Adaptability or versatility
If multiple components are used to transmit force, then valve actuation can be controlled, but manufacturing costs increase
Solution Approach 1:
The patent merges multiple separate components (swing arm, variable arm, driving arm, rocker arm) into a single integrated driven cam structure. The driven cam incorporates the cam face, the force transmission path, and the valve actuation function all in one component, eliminating the need for separate arms and rocker mechanisms while maintaining the ability to regulate valve lift time and distance.
Solution Approach 2:
The patent extracts and eliminates unnecessary intermediate components (swing arm, variable arm, driving arm, rocker arm) from the force transmission path, keeping only the essential driven cam that directly transmits force from the driving cam to the valve. This reduction in component count simplifies manufacturing and reduces costs.
3Adaptability or versatility
If the driven cam rotational axis position is adjustable, then lift time and distance can be simultaneously varied, but the structure becomes more complex
Solution Approach 1:
The patent makes the driven cam rotational axis position dynamic and adjustable rather than fixed. The actuator enables the rotational axis to move along a predetermined path, allowing the cam mechanism to adapt its geometry in real-time to simultaneously vary both lift time and lift distance according to engine operating conditions.
Solution Approach 2:
The actuator serves as an intermediary element that enables controlled adjustment of the driven cam rotational axis position. This mediator component provides the necessary adaptability without requiring a completely complex reconfigurable mechanism, as it simply moves the rotational axis along a predetermined path.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system achieves simultaneous variation of lift time and distance with a simpler structure, reducing manufacturing costs and enhancing stability in valve actuation, while maintaining effective force transmission and reducing the likelihood of malfunctions.
Implementation Method 1
a driven cam pressed by the driving cam to be rotated around a first end thereof serving as a rotational axle of the driven cam
Data Source
AI summary
A continuously variable valve actuation (CVVA) system may include a driving cam rotated by a driving force transmitted from a crankshaft, and a driven cam pressed by the driving cam to be rotated around a first end thereof serving as a rotational axle of the driven cam, wherein the driven cam has a cam face at a second end thereof so as to press and open a valve when rotated, and wherein a vertical distance between the rotational axis of the first end of the driven cam and a rotational axis of the driving cam is configured to be adjusted by moving a position of the rotational axis of the first end of the driven cam.