Hydraulic Valve Sealing for Variable Compression Engines
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Solution Overview
Problem
Conventional hydraulic valves in connecting rods for internal combustion engines with variable compression face challenges in maintaining a reliable seal under high hydraulic pressures, leading to potential leakage and operational instability due to deformations in the valve mounting bore.
Innovation Solution
Mechanical decoupling of the hydraulic valve from the connecting rod, combined with pressure-activated seals that expand radially to bridge the sealing gap, and the use of sealing elements in circumferential annular grooves, such as O-rings, Teflon rings, or metal seals, to ensure a permanent sealing function even under high gas and inertial forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional O-ring seals are used in the valve mounting bore, then the hydraulic valve can be sealed under normal conditions, but under high hydraulic pressures the valve mounting bore deforms and the sealing function fails
Solution Approach 1:
The patent changes the physical state and mechanical properties of the sealing element by using a viscoelastic polymer material that can dynamically adjust its stiffness and deformability in response to varying hydraulic pressures, allowing the seal to maintain contact with the bore wall under high pressure conditions where conventional rigid O-rings fail
Solution Approach 2:
The patent employs a composite sealing structure combining a viscoelastic polymer material with specific mechanical properties that integrate flexibility and pressure resistance, creating a sealing element that adapts to bore deformation while maintaining sealing integrity under high hydraulic pressures
2Stability of the object's composition
If the hydraulic valve is rigidly mounted in the connecting rod, then the structure is stable, but the deformations of the valve mounting bore under high gas and inertial forces cannot be bridged
Solution Approach 1:
The patent transitions from a static rigid mounting to a dynamic sealing system where the viscoelastic sealing element can dynamically deform and adapt its shape in real-time to accommodate bore deformations caused by high gas and inertial forces, maintaining sealing contact throughout the operational cycle
Solution Approach 2:
The patent uses a flexible viscoelastic polymer sealing element that can elastically deform to bridge gaps and accommodate dimensional changes in the valve mounting bore, allowing the sealing interface to flex with the bore deformations rather than failing
3Manufacturing precision
If the radial play between hydraulic valve and valve receiving bore is reduced, then the positioning precision is improved, but the seals cannot move radially to maintain contact under high pressures
Solution Approach 1:
The patent utilizes the time-dependent viscoelastic properties of the polymer material to allow radial movement during pressure cycles while maintaining precise axial positioning, changing the material's effective stiffness based on the loading rate and pressure conditions to accommodate both precision and sealing requirements
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 solution ensures reliable operation by maintaining a low leakage rate and effective sealing, even under high hydraulic pressures, by allowing the seals to move radially and maintain contact with the valve receiving bore, thus preventing crosstalk and ensuring the hydraulic valve's switching function is carried out as intended.
Implementation Method 1
The seal can be moved in its sealing seat by the hydraulic pressure present at the supply connection and can be placed sealingly against the wall of the valve receiving bore
Implementation Method 2
The radial seal prevents a loss of pressure or leaks between the first and second working connections
Data Source
Figure 1
Figure 2
Figure 3a
AI summary
The invention relates to a hydraulic valve (8), in particular for switching a control piston (31, 32) in a connecting rod (1) for a variable compression internal combustion engine. The hydraulic valve (8) comprises a valve housing (44) having a first working port (A1) and a second working port (A2) as well as a supply port (P) which can be pressurized with a hydraulic fluid, thereby allowing a movable piston (9) arranged in the valve housing (44) to be displaced against the force of a pre-tensioned spring (10). As a result, the working ports (A1, A2) and the supply port (P) can be sealed against each other and against the atmosphere by means of sealing elements (48, 49, 51, 52) when installed as intended in a valve receiving bore (50) of the connecting rod (1). The sealing elements (48, 49, 51, 52) can be sealed against a wall (78) of the valve receiving bore (50) by the hydraulic pressure.The invention further relates to a connecting rod (1) with such a hydraulic valve (8). According to the invention, the hydraulic valve (8) is provided to be mechanically decoupled from the connecting rod (1).