Connecting Rod Length Adjustment with Integrated Oil Scraper
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Solution Overview
Problem
Internal combustion engines face inefficiencies due to splashing losses when adjusting connecting rod lengths, as existing solutions do not effectively integrate oil scraper arrangements with shift guide plates for optimal oil stripping and length adjustment.
Innovation Solution
A pre-assembled unit combining shift guide plates and a stationary oil scraper arrangement, where shift guide plates are fixed to a carrier frame that can be displaced, allowing for efficient oil stripping and connecting rod length adjustment, with features like a cast oil scraper arrangement, a torsionally stiff carrier frame, and a spring-prestressed actuating mechanism for failsafe operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If shift guide plates are used to adjust connecting rod length, then variable compression ratio is achieved, but splashing losses increase due to inadequate oil stripping
Solution Approach 1:
The patent combines the shift guide plate arrangement for connecting rod length adjustment with a stationary oil scraper arrangement into a single integrated unit. The shift guide plates are fixed to a carrier frame that is mounted in the stationary oil scraper arrangement, allowing both functions (length adjustment and oil stripping) to be performed simultaneously without requiring separate mechanisms, thereby reducing splashing losses while maintaining variable compression ratio capability
2Ease of manufacture
If oil scraper arrangement is designed as a cast part, then manufacturing cost is reduced, but integration with shift guide plates becomes more complex
Solution Approach 1:
The stationary oil scraper arrangement is designed as a single cast part that integrates multiple functions: it provides the structural housing for the oil scrapers, the mounting structure for the carrier frame with shift guide plates, and the oil return pathways. This unified cast design simplifies manufacturing compared to assembling multiple separate parts, while the internal geometry of the cast part accommodates the integrated shift guide plate mechanism
3Manufacturing precision
If carrier frame is made torsionally stiff, then positioning precision is improved, but material usage increases
Solution Approach 1:
The carrier frame is designed with varying structural properties in different regions: sections requiring high torsional stiffness (such as areas supporting the shift guide plates and connecting to the oil scraper arrangement) are reinforced with increased material or optimized cross-sections, while other sections use minimal material sufficient for their specific functions. This localized reinforcement achieves the required positioning precision without unnecessarily increasing overall material usage
Data Source
AI summary
An apparatus for adjusting the length of connecting rods in an internal combustion engine, having a shift guide plate arrangement which has shift guide plates which can be adjusted in one spatial direction for actuating connecting rod actuating devices which are integrated into the connecting rods for the purpose of changing the length of the respective connecting rod. The shift guide plates are connected fixedly to a carrier frame. The carrier frame is mounted in a stationary oil scraper arrangement such that it can be displaced in the spatial direction. The oil scraper arrangement has oil scrapers for stripping oil from the connecting rods.