Variable Compression Rod With Hydraulic Phase Change
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing connecting rods for variable compression ratio engines are sensitive to engine temperature and load, leading to inefficient energy use and mechanical stress, with previous solutions either requiring complex active control systems or redesigning engine architecture.
Innovation Solution
A connecting rod with variable length, featuring a cylinder, piston, high-pressure, and low-pressure hydraulic chambers connected by calibrated conduits, and mechanical return means, ensuring behavior independence from hydraulic fluid temperature and allowing adjustment of volumetric ratio based on average combustion forces without active control systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a hydraulic chamber is used to adjust connecting rod length, then compression ratio can be varied, but the system becomes sensitive to hydraulic fluid temperature changes
Solution Approach 1:
The patent changes the physical state of the hydraulic fluid from liquid to gas (vapor) by heating it above its saturation temperature. This phase change creates a compressible fluid cushion that is insensitive to temperature variations, as the gas phase can accommodate volume changes without significant pressure variations, thereby resolving the temperature sensitivity issue while maintaining compression ratio adjustability
Solution Approach 2:
The patent utilizes the phase transition of the hydraulic fluid from liquid to vapor phase. By heating the fluid to exceed its saturation temperature, it transforms into a gas that forms a compressible cushion. This phase transition enables the hydraulic chamber to become temperature-insensitive, as the gas phase naturally accommodates thermal expansion and contraction without causing the sensitivity problems associated with liquid hydraulic systems
2Measurement precision
If active control systems are used to adjust connecting rod length, then precision control is achieved, but device complexity increases
Solution Approach 1:
The patent implements a self-regulating system where the heated hydraulic fluid automatically responds to combustion forces without external control. The gas cushion forms naturally when the fluid exceeds its saturation temperature, and the connecting rod length adjusts automatically based on the combustion pressure, eliminating the need for sensors, actuators, or control algorithms while maintaining precision
Solution Approach 2:
The patent uses a pneumatic-hydraulic hybrid approach where a heated liquid transforms into a gas cushion to provide the force transmission medium. This allows precision control of connecting rod length through pressure-driven automatic adjustment, leveraging the incompressibility of liquid for stable pressure generation and the compressibility of gas for smooth length variation, all without active control systems
3Use of energy by moving object
If connecting rod length is varied to adjust compression ratio, then energy efficiency improves, but mechanical stress on components increases
Solution Approach 1:
The patent pre-heats the hydraulic fluid above its saturation temperature before the engine operates, so that when combustion forces are applied, the fluid is already in a state ready to form a compressible gas cushion. This beforehand preparation ensures that the transition to gas phase absorbs the combustion forces smoothly, preventing mechanical shocks and reducing stress on the connecting rod and other components while enabling compression ratio adjustment for improved energy efficiency
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
The solution provides a stable and efficient adjustment of the compression ratio independent of engine temperature and load, reducing mechanical stress and energy losses, while maintaining traditional engine architecture.
Implementation Method 1
a first hydraulic chamber called 'high pressure' capable of transmitting compression forces
Implementation Method 2
a second hydraulic chamber called 'low pressure' capable of transmitting tensile forces
Implementation Method 3
at least one calibrated conduit allowing the flow of hydraulic fluid between the low-pressure chamber and the high-pressure chamber
Data Source
Figure 1A~2
Figure 3~4
Figure 5
AI summary
The invention relates to a rod (1), the length of which is variable, for adjusting the compression ratio of an engine, comprising a cylinder (2) rigidly connected to a first end (E1) of the rod (1); a piston (3) which is movable within the cylinder (2), is rigidly connected to the second end (E2) of the rod, and defines, in the cylinder, a first hydraulic chamber (4) referred to as the "high pressure" hydraulic chamber and capable of transmitting compression forces and a second hydraulic chamber (5) referred to as the "low pressure" hydraulic chamber and capable of transmitting tensile forces; at least one pipe (6) calibrated to enable fluid to flow between the low-pressure chamber (5) and the high-pressure chamber (4); and return means (7) to bring the rod back to its nominal length. The rod (1) is characterized in that cross-sections of the low-pressure hydraulic chamber (5) and the high-pressure hydraulic chamber (4) are equal.