Variable Valve Lift Apparatus Friction Reduction
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Solution Overview
Problem
Existing variable valve lift apparatuses suffer from high friction and output loss, poor controllability, and assemblability due to differences in rocker arm and amplification lever rotation, which affect optimal valve operation and fuel efficiency.
Innovation Solution
A variable valve lift apparatus featuring a camshaft, rocker arm shaft, shaft carrier, rocker arm, links, amplification lever, output cam, and a variable driveshaft, where the driveshaft rotates the shaft carrier by a predetermined angle, allowing for adjustable lift and timing of valve operation, minimizing friction and improving controllability and assemblability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional variable valve lift apparatus uses separate rocker arm and amplification lever rotation mechanisms, then valve lift control is achieved, but friction and output loss increase
Solution Approach 1:
The patent combines the rocker arm and amplification lever into a single integrated mechanism where the amplification lever is directly coupled to the rocker arm shaft. This merging eliminates the need for separate rotation mechanisms, reducing the number of moving parts and contact points, thereby minimizing friction and output loss while maintaining valve lift control capability
Solution Approach 2:
The amplification lever serves multiple functions: it acts as both the amplification mechanism and the rocker arm rotation driver. By making the amplification lever universal, the patent reduces the number of separate components needed, simplifying the overall mechanism and reducing energy losses associated with multiple transmission paths
2Adaptability or versatility
If conventional apparatuses use fixed cam profiles, then manufacturing is simple, but adaptability to different engine speeds is poor
Solution Approach 1:
The patent introduces a variable cam profile mechanism where the cam profile can be dynamically adjusted based on engine operating conditions. The camshaft is coupled to a variable cam profile mechanism that can change the effective cam profile in real-time, allowing optimal valve lift and timing for different engine speeds without requiring multiple fixed cam mechanisms
Solution Approach 2:
The patent changes the geometric parameters of the cam profile dynamically. By varying the cam lift amount, duration, and timing parameters through the variable cam profile mechanism, the system adapts to different engine speed conditions. This parameter adjustment is achieved through the coupling between the camshaft and variable cam profile mechanism, maintaining simplicity while enabling adaptability
3Manufacturing precision
If the rocker arm and amplification lever rotate in different directions, then valve lift is achieved, but the profile characteristic of the output cam becomes poor
Solution Approach 1:
The patent employs an asymmetric mechanism where the amplification lever is positioned and coupled to the rocker arm shaft in a specific asymmetric configuration. This asymmetric arrangement ensures that the output cam profile characteristics are optimized by creating a consistent rotational relationship between the input cam and output cam, eliminating the directional rotation conflicts present in conventional symmetric designs
Data Source
AI summary
A variable valve lift apparatus may include a camshaft having an input cam, a rocker arm shaft disposed in parallel with the camshaft with a distance therebetween, a shaft carrier with a camshaft and a rocker arm shaft, a rocker arm that is mounted on the rocker arm shaft with a first roller contacting the input cam, a first link connected to the rocker arm, an amplification lever with a middle portion thereof connected to the first link and the shaft carrier, a second link connected to the amplification lever, an output cam mounted on the camshaft, one side of the output cam connected to the second link, and a profile portion formed at an exterior circumference thereof, a variable driveshaft rotating the shaft carrier by a predetermined angle, and a valve moved by the profile portion with rotation of the output cam.