Connecting Rod Stem Recesses for Mass Optimization
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Solution Overview
Problem
Conventional connecting rods for internal combustion engines have a high mass and an unfavorable center of gravity distribution, which can affect engine performance and efficiency.
Innovation Solution
The connecting rod features a stem portion with an I-beam cross-section and oppositely facing surfaces that include grooved or recessed portions, reducing the web thickness and redistributing the mass to optimize the center of gravity and reduce weight, thereby controlling rotating and reciprocating mass distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the connecting rod uses a conventional solid stem design, then the structural strength is sufficient, but the mass is high and the center of gravity distribution is unfavorable
Solution Approach 1:
The stem web is segmented by introducing recesses that divide the continuous web into multiple sections. This segmentation reduces material usage and mass while maintaining structural integrity through the distributed reinforcement bars that span across the recesses, resolving the contradiction between reducing weight and maintaining strength.
Solution Approach 2:
The recesses are strategically positioned in specific regions of the stem web where material can be removed without compromising overall strength. The web thickness is varied locally - thinner in regions with recesses and thicker near the ends where strength is critical - allowing mass reduction while preserving necessary structural properties.
2Shape
If recesses are introduced in the stem web to reduce mass, then the center of gravity is optimized, but the web thickness is reduced which may affect strength
Solution Approach 1:
The recesses are designed with asymmetric positioning and varying dimensions to precisely control the center of gravity location. By strategically placing recesses at specific depths and positions within the web, the design optimizes mass distribution and shifts the center of gravity to desired locations while maintaining adequate web thickness for strength.
Solution Approach 2:
The depth, width, and positioning parameters of the recesses are carefully controlled to achieve the desired center of gravity distribution. By adjusting these geometric parameters, the design optimizes mass distribution without reducing web thickness below acceptable strength thresholds, resolving the contradiction between shape optimization and strength maintenance.
Data Source
AI summary
A connecting rod for connecting between a crankshaft and a piston, includes a small end with a cylindrical hole adapted to for receiving a piston pin, a big end having a crank pin bore adapted for receiving a crank pin of a crankshaft and a stem portion extends between the small end and big end. The stem portion can have an I-beam cross-section with a pair of legs and a web extending between the pair of legs. The web includes oppositely facing surfaces defining a thickness that is less than a thickness of the pair of legs. The web includes at least one grooved/recessed portion that is recessed relative to the oppositely facing surfaces of the web.