Hydraulic Support Element Filter Cartridge Design
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Solution Overview
Problem
Existing hydraulic support elements for switchable finger followers in internal combustion engines face contamination issues due to inadequate filtering, leading to impaired lubrication and potential jamming, as contaminants like soot and abraded metal particles enter the oil circuit, compromising the switching function.
Innovation Solution
A double-flow hydraulic support element design with a tubular filter cartridge located in the second pressurized oil chamber, separated from the first by a partition element, allows for a high-performance filtration system without increasing the piston's outside diameter, ensuring contaminants are filtered out before reaching the contact surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a filter is installed in the pressurized oil supply to remove contaminants, then the lubrication quality improves, but the filter area is extremely small and filtering capacity is very low
Solution Approach 1:
The filter cartridge is designed as a hollow body that extends axially within the piston interior space, transforming the filtering surface from a two-dimensional annular area to a three-dimensional cylindrical surface. This dimensional change allows the filter area to be determined by the lateral surface area of the hollow body (π×diameter×length), providing substantially larger filtering capacity within the same compact piston volume.
Solution Approach 2:
The hollow body filter cartridge is nested within the piston interior space, with its hollow interior volume fluidly connected to the pressurized oil supply. This nesting arrangement allows the filter structure to occupy the existing internal volume of the piston without increasing the outside diameter, maximizing filter area while maintaining compact dimensions.
2Reliability
If the piston outside diameter is increased to accommodate a larger filter, then the filtering capacity increases, but the support element dimensions increase
Solution Approach 1:
Instead of increasing the radial dimension (outside diameter) to accommodate more filter area, the solution extends the filter area axially by using a hollow body that spans a significant portion of the piston interior length. This transforms the filtering capacity enhancement from a radial expansion to an axial utilization, maintaining compact outer dimensions while providing substantial filter surface area.
Solution Approach 2:
The hollow body filter is nested within the existing piston interior space, utilizing the available volume without requiring external expansion. The hollow body's outer surface becomes the filtering surface, while its hollow interior serves as the oil passage, achieving dual functionality within the same spatial envelope.
3Adaptability or versatility
If a double-flow design with two pressurized oil chambers is used, then the switching function is enabled, but the oil circuit becomes vulnerable to contamination from soot and abraded metal
Solution Approach 1:
The hollow body filter cartridge is positioned in the second pressurized oil chamber to pre-filter the oil before it reaches the contact head and lubricates the contact surfaces. This preliminary filtering action prevents contaminants from entering the critical lubrication pathway, protecting the switching mechanism from contamination while maintaining the double-flow design's switching capability.
Solution Approach 2:
The filtering function is extracted as a separate, dedicated component (hollow body filter cartridge) within the second pressurized oil chamber, distinct from the main piston structure. This extracted filtering element specifically addresses the contamination issue in the lubrication pathway without interfering with the dual-chamber switching mechanism's 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
This design effectively filters contaminants, maintaining lubrication and switching functionality by providing a large filter area within the existing dimensions, preventing damage and jamming, and ensuring reliable operation of the switchable finger follower.
Implementation Method 1
The piston has a filter cartridge in the form of a hollow body, which can be charged from the outside with pressurized oil and the interior space of which is fluidly connected to the outlet opening of the contact head
Data Source
AI summary
This disclosure relates to a hydraulic support element for a switchable rocker arm of a valve train of an internal combustion engine. The hydraulic support element includes a cup-shaped cylinder, within which a hollow piston is arranged in an axially displaceable manner. The piston includes a filter cartridge which is in the form of a hollow body and can be charged from the outside with pressurized oil and an interior space of which is connected to an outlet opening of the contact head. An interior space of the piston has two pressurized oil chambers, including a first pressurized oil chamber above the piston head and connected to a first pressurized oil feed, and a second pressurized oil chamber formed under the contact head and connected to a second pressurized oil feed. The filter cartridge is tubular and located in the second pressurized oil chamber.