Variable Valve Mechanism Pin Adjustment
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Solution Overview
Problem
Variable valve mechanisms in internal combustion engines face deviations in valve opening and closing amounts due to component dimension deviations, leading to deteriorated engine performance.
Innovation Solution
A variable valve mechanism with a control shaft, control cam, and control arm featuring eccentric circular sections and multiple pin holes allows for adjustable pin insertion, enabling precise adjustment of valve opening and closing amounts without reassembling the power transmission mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the valve opening and closing amount is determined by fixed component dimensions, then the structure is simple, but the valve timing cannot be adjusted when component dimensions deviate, leading to deteriorated engine performance
Solution Approach 1:
The control arm is segmented with multiple pin holes at different positions, allowing the connecting pin to be selectively inserted into different holes to adjust the valve opening and closing amount. This segmentation enables discrete adjustment positions without requiring a completely different mechanism for each adjustment level.
Solution Approach 2:
The mechanism transitions from a fixed configuration to a dynamically adjustable one by allowing the connecting pin to be removed and reinserted at different pin holes on the control arm, enabling the valve timing to be adjusted according to actual engine performance requirements.
2Ease of operation
If the connecting pin is permanently fixed to the power transmission mechanism, then the structure is simple, but adjustment of valve timing requires complete disassembly and reassembly of the power transmission mechanism
Solution Approach 1:
The connecting pin changes from a permanently fixed state to a detachable and reattachable component, enabling easy adjustment of valve timing by simply removing the pin, changing its position in the pin holes, and reattaching it, without requiring disassembly of the entire power transmission mechanism.
Solution Approach 2:
The detachable connecting pin acts as an intermediary element that can be easily removed and repositioned, serving as a simple adjustment mechanism that connects the control arm to the power transmission mechanism without requiring complex fastening or reassembly procedures.
3Manufacturing precision
If high precision manufacturing is used for all components, then the valve timing accuracy is high, but the manufacturing cost increases
Solution Approach 1:
The adjustment function is segmented into discrete pin hole positions on the control arm, allowing the system to achieve accurate valve timing through selective positioning rather than requiring all components to be manufactured with high precision. This reduces manufacturing costs while maintaining timing accuracy.
Solution Approach 2:
The valve timing is adjusted by changing the positional parameter of the connecting pin among multiple discrete pin holes, rather than requiring precise manufacturing of all components. This allows for accurate valve timing through parameter selection rather than through high-precision manufacturing of every component.
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 solution allows for easy and accurate adjustment of valve opening and closing amounts, reducing component accuracy requirements and improving engine performance by synchronizing valve timing across cylinders.
Implementation Method 1
a control cam provided on the control shaft and having a circular sectional shape whose center is eccentric with respect to an axial center of the control shaft
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
The present invention provides a variable valve mechanism includes a drive shaft, a drive cam, a power transmission mechanism that transmits power from the drive cam to a valve, and an opening and closing amount variable mechanism that displaces an intermediate portion of the power transmission mechanism to change an opening and closing amount of the valve. The opening and closing amount variable mechanism includes a control shaft, a control cam, and a control arm that has a rear end portion rotatably externally attached to the control cam and a distal end portion provided with a plurality of pin holes to which the distance from the center of the control cam varies from each other, and swingably supports the intermediate portion of the power transmission mechanism in a circumferential direction of the control cam by selectively inserting one connecting pin provided to the intermediate portion of the power transmission mechanism into one of the plurality of pin holes. The opening and closing amount of the valve is adjusted by changing a pin hole into which the connecting pin is inserted.