Variable-length Connecting Rod Indexing Device
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Solution Overview
Problem
Existing variable-length connecting rods for internal combustion engines face challenges in efficiently adjusting length and maintaining precise angular orientation within limited engine space, while minimizing weight and size, and accurately determining rod length for optimal engine control.
Innovation Solution
A connecting rod design featuring a compact indexing device with a direction pin and a bore-cooperating element, along with a target for sensor detection, which allows for variable length adjustment and precise orientation without adding bulk, by positioning the indexing device on the connecting rod head and integrating length determination functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an indexing device is added to prevent longitudinal rotation of connecting rod parts, then the precision of angular orientation is improved, but the device complexity and weight increase
Solution Approach 1:
The indexing device is segmented into two separate elements: a first element integral with the first part and supported by the connecting rod head, and a second element attached to the second part. These elements cooperate to block rotational movement, allowing the indexing function to be distributed and integrated into existing structural components rather than adding a single complex device
Solution Approach 2:
The first element of the indexing device is made integral with the first part and supported by the connecting rod head, merging the indexing function with existing structural components. This integration eliminates the need for separate mounting structures and reduces overall device complexity while maintaining precise angular orientation control
2Adaptability or versatility
If additional components (indexing device, target, sensor) are added to the connecting rod, then the functionality is improved, but the weight and volume increase
Solution Approach 1:
The connecting rod head serves multiple functions: it supports the first element of the indexing device, provides mounting for the target, and acts as a structural connection point. This multi-functionality reduces the need for separate components and minimizes weight while maintaining all required functionalities
Solution Approach 2:
The target is positioned on the second element which is attached to the second part of the connecting rod. This intermediary positioning allows the sensor to detect the target's position for determining connecting rod length without requiring the target to be directly mounted on the connecting rod body, reducing interference with other components and minimizing weight
3Volume of moving object
If the space for moving parts is reduced to minimize engine size, then the compactness is improved, but the positioning precision and reliability of components deteriorate
Solution Approach 1:
The indexing device utilizes the radial dimension by positioning the first element on the connecting rod head at a distance from the longitudinal axis. This spatial arrangement in another dimension allows the indexing elements to cooperate effectively for blocking rotational movement while maintaining a compact overall engine design
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 design ensures reliable, accurate, and compact operation of the connecting rod, preventing rotational movement and vibratory modes, while allowing for precise length determination and reduced weight, thus optimizing engine performance and space utilization.
Implementation Method 1
This can be a Hall effect sensor, in which case the target consists of a magnetic element or a metallic mass.
Data Source
Figure 1a~1b
Figure 2a~2b
AI summary
The invention relates to a connecting rod (1) for an internal combustion engine. The connecting rod (1) consists of a first portion (5a) and a second portion (5b) respectively associated with the head (2) and the foot (3), said portions sliding relative to each other along the longitudinal axis of the connecting rod (1) so as to form a variable-length connecting rod. The connecting rod (1) comprises an indexing device (9) of the first and second portions (5a, 5b) to ensure both of said portions are given a specific relative orientation. According to the invention, the indexing device (9) comprises a first element (9a) which is rigidly connected to the first portion (5a) and supported by the head of the connecting rod (2).