Eccentric Connecting Rod Layout for Compact Compression Ratio Change
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Internal combustion engines with large stroke/bore ratios face space constraints and increased weight due to the need for large hydraulic cylinders to adjust compression ratios, which also require additional space for swiveling movements.
Innovation Solution
A connecting rod design with a ring-shaped eccentric and oil chambers that utilize oil pressure to adjust the eccentric setting, eliminating the need for traditional hydraulic cylinders, allowing for a space-saving and dual-action mechanism with multiple oil chambers and a lubricant supply system for efficient torque transmission and locking mechanisms to maintain the eccentric position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional hydraulic cylinders are used to adjust compression ratio, then the compression ratio can be changed, but the device requires large design space and increases overall weight
Solution Approach 1:
The patent merges the hydraulic cylinder function with the connecting rod structure itself. The oil chamber is integrated into the connecting rod head, and the eccentric is mounted directly on the connecting rod pin, eliminating the need for separate external hydraulic cylinders. This integration reduces the design space while maintaining the compression ratio adjustment capability.
Solution Approach 2:
The eccentric mechanism is nested within the connecting rod structure. The eccentric is mounted on the connecting rod pin, which is itself part of the connecting rod assembly. The oil chamber is nested within the connecting rod head, creating a compact nested arrangement that saves space compared to external hydraulic cylinders.
2Adaptability or versatility
If traditional hydraulic cylinders are used to adjust compression ratio, then the compression ratio can be changed, but the overall weight of the device increases
Solution Approach 1:
The patent combines multiple functions into the connecting rod assembly: the connecting rod itself, the eccentric mechanism, and the hydraulic actuation system are merged into a single integrated structure. This eliminates the weight of separate external hydraulic cylinders while maintaining the compression ratio adjustment capability.
Solution Approach 2:
The connecting rod assembly serves multiple functions: it transmits force from the piston to the crankshaft, provides the eccentric mechanism for compression ratio adjustment, and houses the hydraulic oil chamber for actuation. This multi-functionality reduces the need for additional separate components, thereby reducing overall weight.
3Productivity
If large stroke/bore ratio is used, then engine performance is improved, but space constraints increase due to tight clearance for connecting rod movement
Solution Approach 1:
The eccentric mechanism is nested within the connecting rod structure, utilizing the existing space within the connecting rod head and pin area. This nested arrangement allows the compression ratio adjustment mechanism to fit within the tight clearance available in engines with large stroke/bore ratios, without requiring additional external space.
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 reduces the overall weight and space requirements while maintaining efficient compression ratio adjustment, minimizing wear and fatigue, and ensuring reliable operation under pressure fluctuations.
Implementation Method 1
an oil pressure in the oil chamber exerts a force on the protrusion to change the eccentric setting of the eccentric
Data Source
AI summary
The connecting rod head includes at least one oil chamber and an eccentric comprises a protrusion reaching into the oil chamber, so that an oil pressure in the oil chamber exerts a force on the protrusion to change the eccentric setting of the eccentric.