Two-Flow Hydraulic Support Element for Valve Train Actuation
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Solution Overview
Problem
Existing hydraulic support elements for internal combustion engine valve trains suffer from non-optimal response behavior and imprecise control times due to large dead volumes in the hydraulic medium, leading to delayed actuation of the coupling means in the finger lever.
Innovation Solution
A two-flow hydraulic support element with a pot-shaped housing and a piston that includes a sleeve with different diameter sections, creating separate and isolated hydraulic paths for play compensation and coupling, significantly reducing the volume of the control space to achieve rapid and precise actuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cap-shaped element is inserted into the hollow pressure piston to separate two flow paths, then hydraulic play compensation and coupling means supply can be realized separately, but a relatively large dead volume is formed above the cap-shaped element leading to non-optimal response behavior
Solution Approach 1:
The patent extracts the problematic cap-shaped element that created large dead volume and replaces it with a sleeve closed at one end inserted into the pressure piston. This sleeve design eliminates the dead volume above a cap while maintaining the separation of the first flow path (for play compensation) and second flow path (for coupling means), thereby improving response time without sacrificing control precision.
Solution Approach 2:
The patent segments the hydraulic support element into distinct functional zones using the sleeve structure. The sleeve closed at one end creates clear separation between the storage space for play compensation and the control space for coupling means, allowing independent optimization of each function's hydraulic characteristics.
2Reliability
If a deflection sleeve with a long axial area is used to provide ventilation and calming section, then air bubbles can be discharged and hydraulic medium can be calmed, but the volume of the storage space increases leading to delayed actuation
Solution Approach 1:
The patent applies local quality by providing ventilation and calming functionality only where needed - in the first flow path for play compensation - while keeping the second flow path for coupling means free of such volume-consuming features. The sleeve structure allows localized air discharge and medium calming without creating large dead volumes that would delay actuation.
3Manufacturing precision
If separate flow paths are implemented for play compensation and coupling means, then precise control can be achieved, but the device complexity increases
Solution Approach 1:
The sleeve closed at one end serves multiple functions simultaneously: it separates the two flow paths, defines the storage space for play compensation, provides structural support, and enables the necessary hydraulic connections. This multi-functionality achieves precise control through separate flow paths without proportionally increasing device complexity.
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 design enables very short and precise control times at low rotational speeds by minimizing the volume of the control space, ensuring efficient hydraulic supply to both the play compensation device and the coupling means, thereby reducing delay times and enhancing the responsiveness of the valve train.
Implementation Method 1
a first flow path for supplying a hydraulic medium to a play compensation device
Implementation Method 2
a second flow path for supplying a hydraulic medium to coupling means in a contacting, switchable finger lever
Implementation Method 3
A retaining valve within the hydraulic play compensation device is formed with a ball that closes a hole in a bottom of a work piston
Implementation Method 4
wherein the valve spring presses the ball axially with a defined mechanical pretensioning force against the open end of the hole in the piston bottom
Implementation Method 5
wherein a compression spring is supported between the flange of the cap and a bottom surface of a cylindrical space of the housing of the support element for generating the necessary contact force
Data Source
AI summary
A double-flow hydraulic support element for a switchable finger lever of a valve train of an internal combustion engine is provided. A piston is arranged in an axial bore of the housing of the support element in an axially movable manner, and the piston includes a hollow cylindrical pressure part and a cup-shaped working part. A head of the pressure part is used as a support for the finger lever and projects beyond the housing edge, and an opening for the flow of a hydraulic medium is formed in the end face of the head. The housing has a first passage and a second passage axially spaced from the first passage for the hydraulic medium. The support element has a hydraulic play compensation device with a ball non-return valve for the finger lever. In order to achieve an optimal actuation of the coupling element, a sleeve which is closed on one side is inserted into the pressing part; the closed end of the sleeve reaches the region of an outer annular groove in a sealing manner below the dome-shaped head of the pressing part; a storage space for supplying the play compensation device with the hydraulic medium is formed radially within and axially outside of the sleeve, in the pressure part, and in the working part of the piston; the storage space is connected to the first passage in the housing via a passage opening in the working part; an actuation space formed between the sleeve and the pressure part of the piston for hydraulically supplying the coupling device is connected to the second passage in the housing via a radial passage opening in the pressure part; and the volume of the storage space is substantially greater than the volume of the actuation space.