Variable Compression Ratio Device Using Eccentric Cam
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Solution Overview
Problem
Conventional variable compression ratio devices require a power source and complex link systems, increasing engine weight and complexity, making it difficult to efficiently change the compression ratio and improve fuel efficiency.
Innovation Solution
A variable compression ratio device using an eccentric cam on the connecting rod's big end portion, rotated by hydraulic pressure, to adjust the compression ratio of the fuel-air mixture, simplifying the structure and reducing weight and friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a variable compression ratio apparatus uses links and a motor to change the top dead center of the piston, then the compression ratio can be adjusted, but the engine weight increases and the design becomes complicated
Solution Approach 1:
The invention extracts and eliminates the complex link mechanism from the variable compression ratio system. Instead of using multiple links to change the top dead center, the patent uses a simplified design where the piston directly changes the compression ratio by adjusting its position within the cylinder, removing the unnecessary intermediate linkages and reducing overall system complexity.
Solution Approach 2:
The invention replaces the mechanical link and motor system with a more efficient mechanism. The patent uses a combination of a movable piston and a specially designed compression ratio adjustment mechanism that operates without requiring heavy motors or complex linkages, thereby reducing both weight and mechanical complexity.
2Adaptability or versatility
If a variable compression ratio apparatus uses links and a motor to change the top dead center of the piston, then the compression ratio can be adjusted, but the engine weight increases
Solution Approach 1:
The invention extracts and eliminates the heavy motor and link components from the variable compression ratio system. The patent achieves compression ratio adjustment through a lighter mechanism involving piston position control, removing the weight burden of motors and complex linkages while maintaining the essential functionality.
Solution Approach 2:
The invention replaces the heavy mechanical motor and link system with a lighter alternative mechanism. The patent uses a streamlined piston-driven system that achieves the same compression ratio adjustment capability without requiring heavy motors, thereby significantly reducing the moving weight of the engine.
3Productivity
If the volume of compressed air is not easy to change, then the compression ratio cannot be adjusted, but this makes it difficult to improve fuel efficiency
Solution Approach 1:
The invention applies dynamics by making the piston position adjustable during engine operation. The patent enables the piston to move to different positions within the cylinder, dynamically changing the compression ratio based on operating conditions. This dynamic adjustment capability allows the system to optimize fuel efficiency across different load conditions while maintaining ease of operation.
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 device effectively improves fuel consumption by varying the compression ratio based on engine conditions, reducing structural changes to the conventional engine and enhancing durability by minimizing weight and friction.
Implementation Method 1
a cam rotation unit provided inside the eccentric cam and rotating the eccentric cam in a clockwise or counterclockwise direction in a hole of the big end portion by a selectively supplied hydraulic pressure
Data Source
AI summary
A variable compression ratio device mounted to an engine, the engine rotating a crankshaft using a combustion force of a gas mixture and a piston, the variable compression ratio device changing a compression ratio of the mixture and including a connecting rod including a small end rotatably connected to the piston and a big end portion formed with a circular hole to be eccentrically rotatably connected to the crankshaft, a crank pin provided in the crankshaft, an eccentric cam provided to be concentrically rotatable in the hole of the big end portion and having a crank pin mounting hole eccentrically inserted with the crank pin to be rotatably connected, and a cam rotation unit provided inside the eccentric cam and rotating the eccentric cam in a clockwise or counterclockwise direction in a hole of the big end portion by a selectively supplied hydraulic pressure.