Rotary Engine Vane Actuation for Variable Compression
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Solution Overview
Problem
Traditional rotary engines have a fixed compression and expansion ratio, limiting their thermodynamic efficiency and flexibility in operation, as they rely on continuous sealing contact between vanes and the rotor, which restricts the ability to alter the thermodynamic cycle dynamically.
Innovation Solution
The rotary device features radially retractable vanes controlled by an actuator and biasing device, allowing for selective variation of the compression and expansion ratios during each rotor revolution, enabling operation in different thermodynamic cycles such as the Otto or Ideal cycle, and decoupling the compression and expansion stages for improved efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vanes continuously seal against the rotor, then reliable sealing is achieved, but the compression ratio and expansion ratio remain fixed
Solution Approach 1:
The vanes are designed to be radially movable rather than fixed, allowing them to dynamically adjust their radial position. This enables the compression ratio and expansion ratio to vary continuously during rotor rotation while maintaining sealing contact through the biasing device that keeps vanes engaged with the rotor surface.
Solution Approach 2:
The system changes the physical parameter of vane radial position to achieve variable compression and expansion ratios. By controlling the radial movement of vanes through actuators, the thermodynamic cycle parameters can be adjusted in real-time without compromising the sealing function.
2Device complexity
If fixed compression and expansion ratios are used, then simple structure is maintained, but thermodynamic efficiency is limited
Solution Approach 1:
The vane control system introduces dynamic adjustment capability allowing the compression and expansion ratios to be optimized for different operating conditions. This dynamic control enables the engine to achieve higher thermodynamic efficiency by adapting the thermodynamic cycle to match actual performance requirements.
3Adaptability or versatility
If vanes are radially retractable, then thermodynamic cycle flexibility is improved, but device complexity increases
Solution Approach 1:
The radially retractable vane design incorporates actuators and biasing devices that enable dynamic adjustment of vane position. This allows the system to select between different thermodynamic cycles (Otto, Ideal, etc.) and continuously vary compression/expansion ratios, achieving high adaptability despite the increased mechanical complexity.
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 enhances thermodynamic performance by allowing continuous alteration of the compression and expansion ratios, potentially exceeding that of Brayton cycle engines, and enables on-the-fly adaptation to varying fuel characteristics and performance requirements.
Implementation Method 1
a biasing device for radially moving the vanes to maintain sealing contact between the vanes and the associated peripheral wall during the rotor rotation
Implementation Method 2
an actuator responsive to a control signal for moving each of the vanes radially against the biasing device to a retracted position
Implementation Method 3
the trailing side of the vanes draws an air-fuel mixture into one of the working chambers through the intake port as the leading side of the vane compresses the air-fuel mixture
Implementation Method 4
a spark charge, from the spark plug, ignites the compress air-fuel mixture to expand the air-fuel mixture inside of the working chamber
Data Source
AI summary
A rotary device for an engine includes a stator and a rotor concentric with and rotatable about an axis with respect to the stator. The rotor and the stator cooperate to provide a working chamber. A plurality of vanes are supported for radial movement on one of the stator and the rotor. Fluid is taken into the working chamber through an intake port and exhausted from the working chamber through an exhaust port. A biasing device biases each of the vanes to seal against one of the stator and the rotor. An actuator moves each of the vanes radially against the biasing device to a retracted position to vary a thermodynamic cycle of the rotary device as the rotor rotates with respect to the stator.