Switching Valve Conical Seat Centering High-Pressure Leakage
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Solution Overview
Problem
Existing fuel injector switching valves face issues with leakage due to skewed armature positions and limited centering effects, sensitivity to particles, and inadequate seat design, leading to leaks and reduced high-pressure resistance.
Innovation Solution
A compact, pressure-balanced switching valve design featuring a guide bore with axial symmetry, a throttled channel, conical valve seat surfaces, and a sealing edge with a small seat diameter, along with a leakage gap and bevel, ensures robust operation and high-pressure resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a flat seat is formed with limited support effect, then the valve structure is simple, but leakage occurs due to skewed armature position and particle sensitivity
Solution Approach 1:
The patent applies a conical seat geometry instead of a flat seat, creating a curved sealing surface that provides self-centering effect for the armature. The conical shape with specific opening angles (30-60 degrees) ensures that the sealing edge maintains proper alignment with the seat, preventing leakage caused by skewed positions while still being manufacturable through standard machining processes.
Solution Approach 2:
The patent introduces asymmetric features including the conical seat angle and the offset positioning of the guide section relative to the seat. The guide section has a larger diameter than the seat diameter, creating an asymmetric structure that provides mechanical guidance and prevents particle accumulation, thereby improving sealing reliability without overly complicating manufacturing.
2Strength
If the seat diameter is large, then the valve structure is robust, but leakage occurs at high pressures due to insufficient centering effect
Solution Approach 1:
The conical seat geometry provides a self-centering effect that maintains sealing edge alignment even at high pressures. The curved surface distributes contact forces evenly, preventing localized stress concentrations that could cause leakage, while the seat diameter is optimized to be as small as possible (minimum 0.5mm) to enhance the centering effect without compromising structural robustness.
Solution Approach 2:
The patent optimizes the seat diameter parameter to a minimum value (0.5mm or less) to maximize the centering effect. The conical seat opening angle is also optimized within the range of 30-60 degrees to balance between providing sufficient centering force and maintaining structural strength. These parameter changes ensure reliable sealing at high pressures while keeping the valve compact.
3Manufacturing precision
If the guide section is tightly fitted in the guide bore, then guidance is precise, but tensile loads increase between the guide section and valve piece
Solution Approach 1:
The guide section is designed with a larger diameter than the seat diameter, creating an asymmetric structure where the guide section extends beyond the seat perimeter. This asymmetric configuration provides mechanical guidance through the guide bore while the beveled outer surface redirects tensile loads away from the guide section-seat interface, preventing load concentration and improving overall structural strength.
Solution Approach 2:
The beveled outer surface of the guide section creates a curved transition that redirects tensile loads at an angle away from the critical guide section-seat interface. This curved geometry distributes stresses more evenly and prevents direct tensile loading of the seating area, thereby maintaining guidance precision while improving load resistance.
4Volume of moving object
If the seat length is very short with two functional edges, then the valve is compact, but coating and particle impact resistance is reduced
Solution Approach 1:
The guide section is designed with asymmetric dimensions where its diameter is larger than the seat diameter, and it extends axially beyond the seat perimeter. This asymmetric configuration creates a protective overhang that shields the short seat from direct particle impact and provides a larger surface area for coating application, thereby improving resistance to particle erosion and coating durability while maintaining compact overall dimensions.
Solution Approach 2:
The extended guide section with beveled outer surface acts as a protective shield that intercepts particles before they can directly impact the short seat. This beforehand protection reduces wear and damage to the critical sealing area, allowing the valve to maintain compact dimensions while still providing adequate resistance to particle impact and coating degradation.
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 prevents leakage, enhances centering, and maintains reliable tightness even at high pressures, reducing tensile loads and improving the valve's robustness and dynamics.
Implementation Method 1
the valve seat surface is designed as a conical valve seat surface and that an opening angle of the conical valve seat surface is selected from a range of approximately 80° to approximately 120°. It is also advantageous here that the sealing edge is designed on a conical end face of the valve closing body and that an opening angle of the conical end face is larger than the opening angle of the conical valve seat surface. This enables an advantageous centering effect of the valve closing body in relation to the valve seat surface of the valve piece.
Implementation Method 2
The channel that opens into the space between the guide section and the sealing seat is advantageously designed as a throttled channel. In this case, the channel, in particular an outlet throttle, can be implemented.
Data Source
Figure 1
AI summary
A switching valve (2), which serves in particular as a magnet valve for injection valves of air-compressing, self-igniting combustion engines, has a valve piece (3), on which a valve seat (4) is formed, and a valve closing body (5), which interacts with the valve seat (4) to form a sealing seat. Thereby, the valve piece (3) comprises a guiding section (26), on which the valve closing body (5) is guided with a guiding opening (27). Further, the valve piece (3) has ducts (32, 33), extending into a space (29) between the guiding section (26) and the sealing seat. Hereby, a sealing seat having a diameter (34) of, e.g., 1.8 mm can be realized.