Stepwise Variable Compression Ratio Engine Mechanism
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Solution Overview
Problem
Internal combustion engines face inefficiencies due to fixed compression ratios, leading to suboptimal performance under varying operating conditions, with gasoline engines being under-compressed under throttled conditions and diesel engines being over-compressed, which affects efficiency and engine stability.
Innovation Solution
A stepwise variable compression ratio engine mechanism using eccentric connecting rod bearings with a projection that pivots to adjust compression ratio by admitting and removing lubricating oil from chamber sections, allowing for incremental changes in compression ratio to match operating conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a fixed compression ratio is used in internal combustion engines, then the engine structure remains simple and reliable, but the engine efficiency deteriorates under varying operating conditions
Solution Approach 1:
The patent applies the dynamics principle by making the compression ratio adjustable rather than fixed. The eccentric connecting rod bearing assembly can pivot between multiple discrete positions (e.g., 0°, 45°, 90°, 135°) to dynamically change the compression ratio based on operating conditions. This allows the engine to adapt its compression ratio in real-time, improving efficiency under varying loads while maintaining a relatively simple mechanical structure through stepwise adjustment.
Solution Approach 2:
The patent implements parameter changes by varying the compression ratio through pivoting the eccentric connecting rod bearing assembly to different angular positions. Each position corresponds to a specific compression ratio value, allowing the system to change the compression parameter according to operating requirements. This enables optimization of engine performance across different operating conditions without fundamentally altering the engine architecture.
2Productivity
If gasoline engines operate under throttled conditions with fixed compression ratio, then the engine structure remains simple, but the engine efficiency deteriorates due to under-compression
Solution Approach 1:
The variable compression ratio mechanism dynamically adjusts the compression ratio based on operating conditions. Under throttled conditions, the system can pivot the eccentric connecting rod bearing to achieve a lower compression ratio, preventing under-compression and improving efficiency. This dynamic adaptation allows the engine to maintain optimal performance across the entire operating range without requiring complex continuous adjustment mechanisms.
3Productivity
If diesel engines use high compression ratio for cold starting, then the cold-start characteristics improve, but the engine efficiency deteriorates when warmed up due to over-compression
Solution Approach 1:
The system dynamically adjusts the compression ratio based on engine temperature and operating conditions. During cold starting, the eccentric connecting rod bearing can be positioned to provide high compression ratio for reliable ignition. Once the engine is warmed up, the mechanism pivots to reduce the compression ratio to appropriate levels, preventing over-compression and improving efficiency. This dynamic adaptation eliminates the need to compromise between cold-start and warm-operating efficiency.
4Productivity
If the compression ratio is continuously variable, then the engine efficiency is maximized under all conditions, but the device complexity and mechanical simplicity are compromised
Solution Approach 1:
The patent segments the continuous compression ratio adjustment into discrete steps by dividing the eccentric connecting rod bearing assembly into multiple angular positions (e.g., 0°, 45°, 90°, 135°). Each position corresponds to a specific compression ratio value. This segmentation allows the system to achieve variable compression ratio functionality while maintaining mechanical simplicity through discrete, well-defined positions rather than requiring complex continuous adjustment mechanisms.
Solution Approach 2:
The system implements dynamic compression ratio adjustment through a relatively simple mechanical mechanism that pivots the eccentric connecting rod bearing assembly between discrete angular positions. This dynamic capability allows the engine to adapt its compression ratio in real-time based on operating conditions while maintaining mechanical simplicity and avoiding the complexity of continuous variable mechanisms.
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 solution enables engines to operate more efficiently by adjusting compression ratio in steps, harmonizing diesel and gasoline engine performance, reducing knocking in gasoline engines and improving cold-start characteristics in diesel engines, thereby enhancing overall engine efficiency and stability.
Implementation Method 1
Liquid is admitted to a first chamber section and removed from a second chamber section to pivot the projection and thereby the eccentric coupler in a first direction
Data Source
AI summary
The compression ratio of an internal combustion engine is adjustable in a stepwise fashion, such as by pivoting an extension of an eccentric connecting rod bearing. The projection extends into a chamber defined by a portion of a connecting rod coupling portion of a connecting rod assembly. Liquid is delivered to one side of the projection and removed from the opposite side of the projection to move the projection and thereby the eccentric connecting rod bearing from one position corresponding to one compression ratio to another position corresponding to another compression ratio.