Mass-Optimized Control Slide for Adjustable Connecting Rods
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Solution Overview
Problem
Existing longitudinally adjustable connecting rods for internal combustion engines require complex oil supply paths and massive control slides, which are not structurally simple and efficient, especially under high acceleration forces and limited installation space.
Innovation Solution
The control contours are arranged together in a high-pressure section of the control slide, separated by a sealing section, with closure regions having a smaller cross-section than opening regions, reducing mass and inertial forces, and optimizing the control slide's axis inclination to minimize acceleration influence, allowing for reduced sealing needs and mass optimization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If control contours are arranged separately with traditional sealing, then reliability is maintained, but device complexity and installation space increase
Solution Approach 1:
The patent merges two separate control contours into a single integrated control slide structure with unified sealing. The control slide combines first and second control contours that act on different outlet valves, with a single sealing section providing sealing for both high-pressure regions. This integration reduces the number of separate sealing elements and simplifies the overall structure while maintaining reliable sealing performance.
Solution Approach 2:
The control slide is designed as a multi-functional component that simultaneously performs multiple functions: it acts as a sealing element, a control element for both outlet valves, and a structural support. The single control slide structure replaces what would traditionally require multiple separate components, reducing device complexity while maintaining all necessary functions.
2Weight of moving object
If control slide mass is reduced for better acceleration performance, then inertial forces decrease, but structural strength may be compromised
Solution Approach 1:
The control slide employs local quality optimization by varying the cross-sectional area at different locations. The closure regions have smaller cross-sections than the opening regions, allowing mass reduction in areas where full strength is not required. The sealing section and high-pressure regions maintain sufficient thickness for strength, while other areas are optimized for weight reduction.
Solution Approach 2:
The control slide features asymmetric cross-sectional geometry where closure regions have smaller cross-sections compared to opening regions. This asymmetric design allows the structure to maintain strength where needed (in opening regions that experience higher stresses) while reducing mass in closure regions, optimizing the strength-to-weight ratio.
3Volume of moving object
If control contours are arranged closer together, then installation space is reduced, but separation of high-pressure regions becomes more difficult
Solution Approach 1:
The patent combines multiple control contours and their associated sealing functions into a single integrated control slide structure. The first and second control contours are arranged in the same control slide with a unified sealing section, eliminating the need for separate sealing arrangements for each control contour and reducing overall volume.
Solution Approach 2:
The control slide is segmented into distinct functional regions (low-pressure section, sealing section, high-pressure section with first and second control contours) that are clearly defined but integrated. This segmentation allows for compact arrangement of high-pressure regions while maintaining proper separation and sealing between different functional zones.
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 configuration results in a structurally optimized, lightweight control slide that maintains operational efficiency even under high acceleration forces, reducing installation space requirements and enhancing stability while minimizing mass and inertial forces.
Implementation Method 1
the control slide comprises a low-pressure section with a low-pressure piston for hydraulically actuating the control slide
Implementation Method 2
a hydraulically actuatable control slide that is preloaded by way of a control slide spring
Implementation Method 3
separated therefrom by way of an sealing section disposed therebetween
Data Source
AI summary
A longitudinally adjustable connecting rod with a hydraulic control device for effecting a change in the effective length of the connecting rod is provided. The hydraulic control device comprises a hydraulic control valve which comprises a hydraulically actuatable control slide that is preloaded by way of a control slide spring, and two outlet valves which can be actuated by the control slide by way of two control contours arranged at a distance from one another. The control slide comprises a low-pressure section with a low-pressure piston for hydraulically actuating the control slide. For optimizing the control slide for such a longitudinally adjustable connecting rod, the two control contours are arranged together in a high-pressure section of the control slide which is arranged on one side of the low-pressure section and separated therefrom by way of a sealing section disposed therebetween. The control contours each comprise a closure region with control cams and an opening region adjoining the control cams. The closure region has a smaller cross-section than the opening region. The mass of the section of the control slide disposed between the two closure regions corresponds at most to 0.95 times the envelope volume of this section multiplied by the density of steel (7.85 g/mm3) due to the selection of material and/or the contouring narrowing in comparison with the opening regions. A respective control slide and a reciprocating piston engine are also provided.