Variable Stroke Engine Crankshaft Eccentricity Control
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Solution Overview
Problem
Existing internal combustion engines face challenges in maintaining a constant compression ratio while varying piston stroke, which affects engine efficiency and fuel consumption.
Innovation Solution
A continuously variable displacement engine design featuring a crankshaft with dual angled journals, slider balls, and an actuation piston assembly that allows for controlled translation between high and low eccentricity positions, coupled with a balance mechanism to adjust counterbalance and axial location, enabling sinusoidal motion and optimized compression ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If piston stroke is varied in existing internal combustion engines, then engine displacement and power output can be adjusted, but the compression ratio cannot be kept constant, leading to reduced engine efficiency and increased fuel consumption
Solution Approach 1:
The patent employs dynamic adjustment mechanisms including variable stroke length control and variable compression ratio control that allow the engine to continuously adapt its geometric parameters during operation. The stroke length is varied by adjusting the crankshaft eccentricity position, while the compression ratio is independently controlled through adjustment of the piston position at top dead center, enabling the engine to maintain optimal compression ratio across different displacement settings.
Solution Approach 2:
The invention changes key geometric parameters of the engine mechanism - specifically the crankshaft eccentricity position and piston position - to simultaneously control both stroke length and compression ratio. By varying the eccentricity position of the crankshaft, the stroke length is adjusted, while independent control of piston position ensures compression ratio remains constant, thereby resolving the contradiction between displacement adaptability and energy efficiency.
2Use of energy by moving object
If piston stroke is shortened to reduce engine displacement, then fuel consumption decreases, but the compression ratio varies, reducing engine efficiency
Solution Approach 1:
The system dynamically adjusts the piston position at top dead center through a variable compression ratio control mechanism that operates independently of stroke length variation. This allows the compression ratio to be maintained at its optimal value even when the stroke is shortened for reduced displacement, ensuring engine efficiency and reliability are preserved during fuel-saving operating modes.
Solution Approach 2:
The patent introduces intermediate control mechanisms including a variable stroke length control system and a variable compression ratio control system that act as mediators between the engine's geometric parameters. These control systems coordinate the adjustment of crankshaft eccentricity and piston position to achieve the dual objective of reduced displacement while maintaining constant compression ratio, thereby preserving engine efficiency.
3Reliability
If dual angled journals and slider balls are added to enable stroke variation with constant compression ratio, then engine efficiency is optimized, but device complexity increases
Solution Approach 1:
The control system is segmented into functionally independent modules: a variable stroke length control mechanism that adjusts crankshaft eccentricity, and a variable compression ratio control mechanism that adjusts piston position. This segmentation allows each subsystem to be optimized and controlled independently, managing overall system complexity while achieving the dual control objective.
Solution Approach 2:
The crankshaft design with dual angled journals serves multiple functions: it provides the rotating motion drive, enables variable stroke length through eccentricity adjustment, and works in conjunction with the piston position control to achieve variable compression ratio. This multi-functionality reduces the need for additional separate mechanisms, thereby managing device complexity while achieving the desired performance.
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 allows for continuous variation of piston stroke while maintaining a constant compression ratio, optimizing engine efficiency and fuel usage by controlling the stroke and compression ratio based on engine load.
Implementation Method 1
A first slider ball is engaged on the upper journal and a second slider ball engaged on the lower journal
Implementation Method 2
The actuating piston is controllably translated between a first high eccentricity position and second low eccentricity position
Implementation Method 3
A balance mechanism is adapted to change the amount of counterbalance for the nutator and the axial location of the counterbalance consistent with eccentricity of the nutator
Implementation Method 4
internal combustion engines
Data Source
AI summary
A continuously variable displacement engine has a plurality of pistons received in a cylinder block and connected to a nutator. A crankshaft with an axis of rotation is carried in a crankcase and incorporates an upper journal with a first angle relative to the axis and a lower journal with a second angle with respect to the axis. A first slider ball is engaged on the upper journal and a second slider ball engaged on the lower journal. A carrier assembly captures the first and second slider balls and incorporates an actuating cylinder. An actuation piston assembly is translatably carried in the actuating cylinder and connected to the crankshaft intermediate the upper journal and lower journal. The actuating piston is controllably translated between a first high eccentricity position and second low eccentricity position. An anti-rotational assembly connects the nutator to a piston case. A balance mechanism is adapted to change the amount of counterbalance for the nutator and the axial location of the counterbalance consistent with eccentricity of the nutator.