Variable Valve Transmission Arm Leverage Adjustment
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Solution Overview
Problem
Existing variable valve apparatuses for internal combustion engines face challenges in expanding the range of valve characteristics, particularly due to limitations in the supporting structure and movement range of the transmission arm, which restricts the variability of valve lift and timing.
Innovation Solution
The solution involves adjusting the layout of the transmission arm by varying the B/A value ratio, where B is the distance from the oscillating fulcrum to the point of action and A is the distance from the cam to the fulcrum, to achieve different lever ratios at high and low valve lift controls, allowing for a larger oscillation angle at high lift and a smaller angle at low lift without altering the cam or transmission arm movement range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a transmission arm is moved to change valve characteristics, then valve opening period and lift amount can be varied, but the variable range is limited by the supporting structure and surrounding components
Solution Approach 1:
The invention changes the lever ratio parameter (B/A value) of the transmission arm to achieve different valve lift characteristics. By adjusting the layout positions of the contact point, oscillating fulcrum, and point of action, the system achieves a variable range from high valve lift (θ1) to low valve lift (θ2) without modifying the supporting structure or movement range constraints.
2Length of moving object
If the movement range of the transmission arm is increased to expand variable range, then higher valve lift can be achieved, but the supporting structure and surrounding devices prevent further movement
Solution Approach 1:
The invention makes the lever ratio dynamic by allowing the transmission arm to operate at different positions along its fixed movement range. The system achieves variable valve characteristics (θ1 for high lift, θ2 for low lift) by changing the effective lever arms A and B, rather than requiring the transmission arm to move beyond its structurally constrained range.
3Length of moving object
If the lever ratio is optimized for high valve lift, then high lift amount is achieved, but the oscillation angle becomes too large for low lift control
Solution Approach 1:
The invention applies different lever ratios (B/A values) for different operating conditions. The layout is designed so that θ1 (B/A at high lift) and θ2 (B/A at low lift) are optimized for their respective control needs, allowing precise control at both high and low valve lift levels with appropriately sized oscillation angles for each condition.
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
This approach enables a broader variable range of valve characteristics without changing the cam or transmission arm movement, resulting in higher valve lift at high settings and lower lift at low settings, improving engine efficiency and reducing fuel consumption.
Implementation Method 1
a distance from a contact point between a cam and a transmission arm to an oscillating fulcrum of the transmission arm is defined as A, and a distance from the oscillating fulcrum of the transmission arm to a point of action of the transmission arm is defined as B to thereby determine a B/A value
Data Source
AI summary
A variable valve apparatus of an internal combustion engine adopts a structure in which, a transmission arm is laid out such that, when a distance from a contact point where a cam contacts a transmission arm to an oscillating fulcrum of the transmission arm is defined as A, and a distance from the oscillating fulcrum of the transmission arm to a point of action of the transmission arm is defined as B to thereby determine a B/A value, θ1 as a B/A value at the time of a high valve lift control for controlling valve lift characteristics, and θ2 as a B/A value at the time of a low valve lift control for controlling valve lift characteristics establish a relation of θ1>θ2.