Eccentric Sleeve VCR Engine for Precise Compression Ratio Adjustment
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Solution Overview
Problem
Existing internal combustion engines face difficulties in easily adjusting and changing compression ratios, leading to inefficiencies and increased emissions due to the challenges of using hydraulic and mechanical devices for eccentric sleeve control, which cause noise, vibration, and weight issues.
Innovation Solution
A mechanism that adjusts the effective length of the connecting rod by manipulating the posture of an eccentric sleeve installed on the crankpin, using a planetary gear system to rotate the eccentric sleeve together with the main journal, allowing independent and simple changes in compression ratio without rotating the eccentric sleeve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a hydraulic device is used to rotate the eccentric sleeve, then the compression ratio can be changed, but accurate control of angles of pipes and the eccentric sleeve becomes difficult
Solution Approach 1:
The patent replaces the hydraulic device with a mechanical device consisting of a rod, rack, and gear system. This mechanical substitution enables precise angular control of the eccentric sleeve through gear engagement, while maintaining the ability to adjust compression ratio. The gear mechanism provides inherent mechanical advantage and precise positioning capability that hydraulic systems lack.
2Ease of operation
If a mechanical device including rod, rack, and gear is used to rotate the eccentric sleeve, then the compression ratio can be changed, but strong impact, vibration, and noise occur during fast reciprocating motion and explosion stroke
Solution Approach 1:
The patent makes the connecting rod length variable by allowing the eccentric sleeve to rotate to different positions, thereby dynamically adjusting the effective length of the connecting rod. This dynamic adjustment capability enables the system to adapt to different operating conditions (fast reciprocating motion vs. explosion stroke) by optimizing the connecting rod length, reducing impact and vibration during different phases of engine operation.
3Ease of operation
If a mechanical device including rod, rack, and gear is used to rotate the eccentric sleeve, then the compression ratio can be changed, but weight and space increase
Solution Approach 1:
The patent merges the compression ratio adjustment function with the existing engine components. The eccentric sleeve is integrated into the connecting rod assembly, and the rod-rack-gear mechanism is incorporated into the existing crankshaft and connecting rod structure. This merging approach avoids adding separate, heavy adjustment mechanisms while still achieving variable compression ratio capability.
4Device complexity
If the compression ratio is set at design time, then the engine structure is simple, but the compression ratio cannot be easily changed
Solution Approach 1:
The patent transforms the fixed compression ratio design into a dynamic, adjustable system. By enabling rotation of the eccentric sleeve to different angular positions, the effective length of the connecting rod becomes variable, allowing the compression ratio to be changed based on operating conditions while maintaining a relatively simple overall engine structure.
Data Source
AI summary
In a variable compression ratio engine according to the present invention, an eccentric sleeve is installed on a crankpin, and an effective length of a connecting rod is changed by adjusting a posture of an eccentric sleeve relative to the connecting rod, or an effective length of a crank arm is changed by adjusting a posture of an eccentric sleeve relative to the crank arm. An eccentric sleeve control shaft installed on a main journal or one shaft of a planetary gear system is connected to an eccentric sleeve by means of an eccentric sleeve auxiliary shaft. Automatic adjustment of the compression ratio based on crankshaft rotation speed may be achieved using a rotor, a stator, or a rack.