Variable Compression Connecting Rod Eccentric Lever Design
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Solution Overview
Problem
Existing connecting rods for variable compression internal combustion engines are not cost-effective and lightweight, leading to inefficiencies in fuel burn and vibration, and require complex fabrication processes.
Innovation Solution
A connecting rod design featuring an eccentric element adjustment arrangement with an eccentric element lever that envelopes the eccentric element exclusively in a first portion, eliminating the need for a beveled section, allowing for flat connection sections and simplified laser welding, reducing weight and installation space, and facilitating a more reliable and economical production process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the eccentrical element lever is designed to envelope the eccentrical element in a first portion only with flat connection sections, then the weight and manufacturing cost are reduced, but the connection reliability may be compromised
Solution Approach 1:
The eccentrical element lever is divided into multiple segments (first portion and second portion) with distinct functions. The first portion provides flat connection sections for torque-proof connection, while the second portion provides the beveled contour for structural integrity. This segmentation allows each part to be optimized for its specific function without compromising overall reliability.
Solution Approach 2:
Different portions of the eccentrical element lever have different geometric qualities: the first portion has flat connection sections for reliable torque transmission, while the second portion has beveled contours for structural strength and proper engagement. This local differentiation of properties allows the lever to simultaneously achieve lightweight design and connection reliability.
2Strength
If the eccentrical element lever includes beveled contours, then the structural strength is improved, but the manufacturing complexity and cost increase
Solution Approach 1:
The lever is segmented into a first portion with flat contours (easier to manufacture) and a second portion with beveled contours (provides strength). This allows the complex beveled sections to be limited to only where structurally necessary, reducing overall manufacturing complexity while maintaining strength.
Solution Approach 2:
Instead of providing beveled contours throughout the entire lever, the beveled portions are applied only partially - specifically in the second portion where structural strength is needed. This partial application of the beveled feature reduces manufacturing complexity and cost while still achieving the necessary structural integrity.
3Ease of manufacture
If the eccentrical element lever is designed without a beveled portion, then the manufacturing process is simplified and cost is reduced, but the structural integrity may be compromised
Solution Approach 1:
The lever is divided into functional segments where the first portion uses simple flat contours for ease of manufacture, and the second portion incorporates beveled contours specifically where structural integrity is required. This segmentation ensures that manufacturing simplicity is maintained in non-critical areas while strength is preserved in critical areas.
4Use of energy by moving object
If the eccentrical element lever envelopes the eccentrical element exclusively in the first portion, then the oscillating mass is reduced improving fuel efficiency, but the torque transmission capability may be affected
Solution Approach 1:
The lever is segmented into a first portion that envelopes the eccentrical element for torque transmission, and a second portion that extends beyond it. This segmentation allows the lever to maintain adequate torque transmission capability through the first portion's flat connection sections while reducing overall mass by limiting the enveloping portion.
Solution Approach 2:
Instead of having the lever envelope the entire eccentrical element, the enveloping action is limited to only the first portion. This partial enveloping is sufficient for torque transmission while significantly reducing the oscillating mass of the lever, thereby improving fuel efficiency.
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
The design results in a lighter, more cost-effective connecting rod with reduced oscillating mass, improved vibration characteristics, and enhanced fuel efficiency by optimizing the eccentric element lever configuration and welding process, thereby reducing fuel burn and production costs.
Implementation Method 1
The eccentrical element lever or its eccentrical lever segments are welded together with the eccentrical element. A laser welding method is advantageously used as a welding method.
Data Source
AI summary
A connecting rod for a variable compression internal combustion engine, the connecting rod including a crank bearing eye for connecting the connecting rod with a crankshaft of the internal combustion engine; a connecting rod bearing eye for connecting the connecting rod with a cylinder piston of the internal combustion engine; an eccentrical element adjustment arrangement for adjusting an effective connecting rod length, wherein the eccentrical element adjustment arrangement includes an eccentrical element that cooperates with an eccentrical element lever and that is connected torque proof with the eccentrical element lever, wherein a wrist pin of the cylinder piston is receivable in the eccentrical element, wherein the eccentrical element adjustment arrangement includes two cylinders with a respective piston that is supported in a cylinder bore and connected with a respective support rod, wherein the eccentrical element lever includes one or plural eccentrical element lever segments.