One-Piece Eccentric Lever for Variable-Compression Connecting Rods
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Internal combustion engines with fixed compression ratios face inefficiencies during part-load operations due to limited adjustable compression ratios, leading to suboptimal performance and increased fuel consumption, as higher compression ratios can cause knocking.
Innovation Solution
A connecting rod with a one-piece eccentric lever designed through stamped and bent processes or cold solid forming, featuring a reduced material thickness and integrated joint mounts, allowing for adjustable compression ratios without additional components, thereby reducing manufacturing costs and weight while enhancing mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the compression ratio is increased to improve engine efficiency, then fuel consumption is reduced, but knocking occurs during full-load operation
Solution Approach 1:
The patent implements a variable compression ratio system that dynamically adjusts the compression ratio based on operating conditions. The connecting rod length is changed using an eccentric adjusting device with hydraulic actuators, allowing the engine to use higher compression ratios during part-load operation (reducing fuel consumption) and lower compression ratios during full-load operation (preventing knocking).
Solution Approach 2:
The invention changes the physical parameter of connecting rod length to achieve variable compression ratio. By mechanically adjusting the connecting rod length through the eccentric lever mechanism, the compression ratio can be varied continuously, enabling optimization of fuel efficiency without causing knocking under different load conditions.
2Adaptability or versatility
If a two-part eccentric lever structure is used to achieve variable compression, then adjustability is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent merges the eccentric lever into a one-piece stamped component that integrates multiple functions. The single-piece construction eliminates the need for separate eccentric lever segments and connecting bolts, reducing manufacturing steps while maintaining the variable compression capability through the integrated eccentric geometry.
Solution Approach 2:
The invention uses sheet metal forming processes with specific thickness parameters (e.g., 2-5mm) to create the eccentric lever from a single piece of material. This approach simplifies manufacturing compared to machining or assembling multiple parts, while the stamped geometry provides the necessary eccentric characteristics for compression ratio adjustment.
3Weight of moving object
If material thickness of the eccentric lever is reduced to decrease weight, then fuel efficiency is improved, but mechanical strength and resistance to cracking decrease
Solution Approach 1:
The patent applies different material thicknesses at different locations of the eccentric lever. Thinner sections (2-3mm) are used in non-critical areas to reduce weight, while thicker sections (4-5mm or more) are provided at critical stress points and weld zones to maintain strength and prevent cracking. This localized variation optimizes the weight-strength trade-off.
Solution Approach 2:
The invention uses high-strength steel materials with enhanced mechanical properties to compensate for reduced thickness. The combination of optimized material selection (high-strength tempered steel) with variable thickness design allows weight reduction while maintaining adequate strength and crack resistance in the eccentric lever.
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 solution enables cost-effective and reliable manufacturing of connecting rods for internal combustion engines with variable compression, improving engine efficiency and reducing fuel consumption by allowing adjustable compression ratios without the risk of cracking and maintaining mechanical strength.
Implementation Method 1
the eccentric lever is designed in one piece as a stamped and bent part or produced by means of a cold solid forming process
Implementation Method 2
The eccentric lever can then be welded to the eccentric
Data Source
Figure 1
Figure 2~4
Figure 5~6
AI summary
The invention relates to a connecting rod (1) for a variable-compression internal combustion engine, comprising an eccentric adjustment device (3) for adjusting the effective connecting rod length. The eccentric adjustment device (3) has an eccentric (4) cooperating with an eccentric lever (12) and support rods (7, 8) engaging the eccentric lever (12). According to the invention, the eccentric lever (12) is manufactured in one piece as a stamped and bent part or by means of a cold forming process. The invention further relates to an internal combustion engine with such a connecting rod (1).