Variable Compression Ratio via Oil-Actuated Rods
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Solution Overview
Problem
Conventional internal combustion engines have a fixed compression ratio, leading to fluctuating cylinder pressure due to varying intake manifold pressure, resulting in inefficient engine performance and potential for overcompression or undercompression, which necessitates compensatory measures in other engine systems.
Innovation Solution
The compression ratio is manipulated inversely proportional to changes in intake manifold pressure by controlling the volume of the combustion chamber using slender cylindrical compression rods, adjusted by engine oil pressure, to maintain constant optimum total compression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a fixed compression ratio is used in conventional engines, then the engine structure is simple and manufacturing is easy, but the cylinder pressure fluctuates wildly with intake manifold pressure changes, leading to inefficient engine performance
Solution Approach 1:
The patent applies the dynamics principle by making the compression ratio variable rather than fixed. Compression rods are introduced that can move within the combustion chamber to dynamically adjust the compression ratio in real-time based on intake manifold pressure changes, thereby maintaining optimal cylinder pressure and engine performance across varying operating conditions.
Solution Approach 2:
The patent implements parameter changes by actively varying the compression ratio parameter in response to changing engine conditions. The compression rods adjust the combustion chamber volume to change the compression ratio, allowing the engine to adapt to different intake pressures and maintain optimal performance rather than relying on a fixed design.
2Power
If the compression ratio is increased to improve engine power, then more power is generated, but the risk of overcompression and engine damage increases
Solution Approach 1:
The patent employs feedback control where the engine control system monitors intake manifold pressure and adjusts the compression rod positions accordingly. This feedback mechanism allows the system to increase compression ratio when needed for power while automatically reducing it to prevent overcompression and engine damage, thereby maintaining both power output and reliability.
Solution Approach 2:
By making the compression ratio dynamically adjustable through moving compression rods, the system can optimize power output when conditions permit while preventing excessive compression that would harm engine durability. The dynamic adjustment capability allows the engine to operate safely across a wide range of conditions.
3Reliability
If the compression ratio is decreased to prevent overcompression, then engine durability is improved, but power output and efficiency are reduced
Solution Approach 1:
The dynamic compression ratio adjustment system allows the engine to decrease compression ratio when necessary to prevent overcompression and protect durability, while simultaneously increasing it when conditions allow to maximize power output. This dynamic capability resolves the trade-off between durability and power by allowing both extremes when appropriate.
Solution Approach 2:
The system actively changes the compression ratio parameter based on real-time engine conditions. When intake pressure is low or engine load is light, the compression ratio is reduced to prevent overcompression and maintain durability. When intake pressure is high or power is needed, the compression ratio is increased to maximize power output, thus resolving the contradiction between durability and power.
4Productivity
If compensatory systems are added to handle compression variations, then engine performance is maintained, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent merges the compression adjustment function with the existing piston and valve assembly by introducing compression rods that integrate into the combustion chamber structure. This merging approach allows compression ratio adjustment without adding separate, complex compensatory systems, thereby maintaining performance consistency while minimizing increased device complexity.
Solution Approach 2:
The dynamic compression rod system provides a straightforward mechanical means to adjust compression ratio without requiring complex electronic or hydraulic compensatory systems. The rods can be actuated by existing engine components like the crankshaft or camshaft, integrating the adjustment capability into the fundamental engine mechanics rather than adding separate complex control systems.
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 approach allows for real-time optimization of engine performance, reducing the need for compensatory systems, enabling lighter, more efficient, and durable engines with improved turbocharger response and reduced emissions.
Implementation Method 1
The compression ratio is manipulated inversely proportional to changes in intake manifold pressure by controlling the volume of the combustion chamber using slender cylindrical compression rods, adjusted by engine oil pressure
Data Source
AI summary
In conventional engines, the compression ratio is a constant. Therefore, cylinder pressure increases proportionately with intake manifold pressure. As manifold pressure changes dramatically according to load, a conventional engine cannot maintain anywhere near constant (let alone optimum) cylinder pressure. Below optimum cylinder pressure, the engine is inefficient—above optimum, it suffers undue stress and (depending on fuel) may emit excess nitrous oxides. My invention makes it possible to manipulate the combustion chamber volume, and therefore the compression ratio, while the engine is running. By changing the compression ratio in a manner inversely proportional to changes in manifold pressure, we can maintain a constantly optimized cylinder pressure.