Variable Compression Ratio Engine Vertical Movement Mechanism
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Solution Overview
Problem
Current internal combustion engines with fixed compression ratios compromise between efficiency and reliability, leading to suboptimal fuel efficiency and increased risk of pre-ignition due to limitations in varying compression ratios, which prior variable compression ratio engine designs have failed to address effectively due to issues with weight, complexity, and stability.
Innovation Solution
A system that allows the cylinder head/block assembly to move vertically relative to the crankcase using interlocking frames and various mechanical, electrical, or hydraulic devices, while constraining movement in other directions to adjust compression ratio, utilizing mechanisms like rack and pinion, eccentric cam adjusters, or gearsets to enable high or low compression ratios without increasing engine weight or complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the compression ratio is increased to improve fuel efficiency and power output, then thermal efficiency increases, but pre-ignition and knocking occur causing engine damage
Solution Approach 1:
The patent implements a variable compression ratio mechanism that allows the compression ratio to be dynamically adjusted during engine operation. The cylinder head can be positioned at different heights relative to the crankcase, changing the combustion chamber volume and thus the compression ratio. This enables the engine to operate at high compression ratios for improved efficiency under light load conditions, and switch to lower compression ratios when heavy load or high temperatures increase the risk of knocking and pre-ignition.
2Productivity
If a variable compression ratio mechanism is implemented to improve fuel efficiency, then fuel consumption decreases, but device complexity and weight increase
Solution Approach 1:
The control bolts serve multiple functions: they act as both fasteners to secure the cylinder head to the crankcase and as guide pins that constrain the cylinder head's movement to the vertical axis. This eliminates the need for separate guiding mechanisms, reducing overall system complexity while enabling the variable compression ratio functionality.
Solution Approach 2:
The mechanism separates the cylinder head assembly from the crankcase, allowing independent movement of the cylinder head along the vertical axis. This segmentation enables the compression ratio to be varied without affecting the crankcase structure, simplifying the overall design compared to integrated solutions.
3Productivity
If the cylinder head is allowed to move vertically to adjust compression ratio, then fuel efficiency improves, but movement in other directions causes side loading and component failure
Solution Approach 1:
The control bolts are strategically positioned to provide localized constraint at critical points. The combination of control bolts at different locations creates a constraint system that specifically prevents lateral and rotational movement while allowing vertical movement, addressing the side loading problem at its source rather than requiring a comprehensive restraint system.
Data Source
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AI summary
A system and method for providing a variable compression ratio internal combustion engine is disclosed. The system can include a frame affixed to the engine crankcase and a complementary frame affixed to the block/cylinder head assembly. In other embodiments, the system can use a system of hollow head bolts and control bolts to maintain component alignment. The system can further comprise an actuating system to enable the block/head assembly to be moved up and down with respect to the crankcase, varying the compression ratio of the engine. A number of mechanisms can be used to achieve this movement, including a rack and pinion, a hydraulic or pneumatic actuator, and a gear drive. The compression ratio can be varied continuously during use. The frames and/or head bolt system can substantially limit movement of the engine components to the y-axis, thus reducing, or eliminating, unwanted movement and stresses in other directions.