Crankshaft Eccentric Coupler for Dynamic Compression Ratio Control
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Solution Overview
Problem
Current internal combustion engines lack a practical and cost-effective solution for dynamically varying the compression ratio, which limits their performance and efficiency across different operating conditions and fuel types, particularly in multifuel engines.
Innovation Solution
A device combining an eccentric actuator and rotation coupler mechanisms, controlled by an electronic unit, adjusts the crankshaft position relative to the pistons, using internal and external gears to vary the compression ratio without increasing the number of moving parts, allowing for dynamic adaptation to fuel types and engine conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a dynamic variable compression ratio solution is implemented, then engine performance and efficiency are improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent combines the eccentric actuator mechanism and rotation coupler into a single integrated device that varies compression ratio dynamically. The eccentrics are mounted directly on the crankshaft, and the rotation coupler uses gear interactions (internal gear on crankshaft, external gear on crown) to couple rotational movements, merging multiple functions into one compact assembly rather than separate systems.
Solution Approach 2:
The variable compression ratio device serves multiple functions: it adjusts compression ratio dynamically, maintains crankshaft rotational coupling, and adapts to different fuel types and operating conditions. The electronic control unit integrates with the engine's existing control system, allowing the same device to handle various fuel combinations (ethanol, gasoline, natural gas) and optimize performance across different operating scenarios.
2Productivity
If a dynamic variable compression ratio solution is implemented, then engine performance is improved, but manufacturing cost increases
Solution Approach 1:
By integrating the eccentric actuators directly onto the crankshaft and using the rotation coupler's gear system to maintain rotational coupling, the patent reduces the number of separate components and assembly steps. This merged design simplifies manufacturing compared to alternative solutions that would require separate actuation systems and coupling mechanisms.
Solution Approach 2:
The rotation coupler mechanism uses the inherent rotational movement of the crankshaft itself to drive the compression ratio variation. The eccentrics on the crankshaft automatically convert rotational motion into the vertical displacement needed for compression ratio adjustment, eliminating the need for external motors or complex actuation systems that would increase manufacturing cost.
3Device complexity
If the compression ratio is kept fixed, then device complexity is reduced, but engine performance and fuel efficiency are compromised
Solution Approach 1:
The patent transforms the static, fixed compression ratio into a dynamic variable compression ratio that can be adjusted in real-time based on operating conditions. The eccentrics on the crankshaft enable continuous variation of the compression ratio throughout the engine cycle, allowing the system to adapt dynamically to different fuel types, loads, and speeds rather than being locked into a single fixed ratio.
Solution Approach 2:
The compression ratio parameter is changed dynamically through the eccentric actuator mechanism. By varying the position of the eccentrics on the crankshaft, the compression ratio can be adjusted across a range of values, allowing optimization for different operating conditions such as high-speed/high-load versus low-speed/low-load scenarios, and for different fuel types with different combustion characteristics.
4Adaptability or versatility
If multifuel capability is provided with fixed compression ratio, then adaptability to different fuels is achieved, but engine performance is compromised
Solution Approach 1:
The variable compression ratio device enables dynamic adaptation to different fuel types by adjusting the compression ratio in real-time. When switching between ethanol, gasoline, or natural gas, the electronic control unit modifies the eccentric positions to optimize compression ratio for each fuel's combustion characteristics, rather than being constrained by a fixed ratio that must compromise performance for any single fuel type.
Solution Approach 2:
The compression ratio parameter is varied according to the detected fuel type and operating conditions. The system can increase compression ratio for high-octane fuels like ethanol to maximize thermal efficiency, use appropriate ratios for gasoline, and optimize for natural gas properties, thereby achieving full multifuel adaptability without performance compromise for any specific fuel.
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
Enables improved engine performance, fuel efficiency, reduced emissions, and lower production costs by allowing the compression ratio to be optimized for various operating scenarios, applicable to existing engines through adaptive kits.
Implementation Method 1
an elaborate mechanism, called eccentric actuator, which allows, by means of the movement of these eccentrics, to change, under the command of an electronic control unit, the relative position of the crankshaft in relation to the top dead of the pistons
Implementation Method 2
The second mechanism is the rotation coupler, formed by a gear of internal teeth, the crown and an axis with external teeth gear, the sprocket
Data Source
AI summary
A variable compression ratio device is configured to be incorporated into an internal combustion engine. The internal combustion engine includes one or more cylinders housing pistons that are coupled to a crankshaft. The variable compression ratio device includes a rotation coupler assembly formed by gears that have internal and external teeth, the rotation coupler assembly being disposed at a distal end of the crankshaft to cause the crankshaft to rotate. Translation variations of the crankshaft are to be converted into rotation and transmitted to at least one of a toothed gear or a flange of a flywheel.