Fuel Cell Coolant Valve Seal Design for Leakage Prevention
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Solution Overview
Problem
Existing coolant control valves for fuel cell stacks in vehicles suffer from water leakage due to poor sealing, particularly caused by the vulnerability of polytetrafluoroethylene (PTFE) seals to heat and cold, low restoring ability, increased wear leading to pressure-induced leaks, and high manufacturing costs due to complex structures with multiple parts.
Innovation Solution
A coolant control valve with a seal made of fluororubber (FKM) that minimizes friction and enhances durability by using a metal insert and tension spring to maintain contact with the plunger shaft, reducing the need for peripheral parts like seal washers and snap rings, and incorporating a dust lip for foreign substance prevention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a PTFE seal is used to seal the plunger shaft, then the manufacturing cost is reduced and the structure is simplified, but the sealing reliability deteriorates under intense heat and cold conditions
Solution Approach 1:
The patent uses a composite sealing structure combining PTFE material with a reinforcement layer (such as fabric or mesh) embedded within the seal. This composite construction maintains the low friction and chemical resistance properties of PTFE while adding structural integrity to resist degradation under intense heat and cold conditions, thereby resolving the contradiction between manufacturing simplicity and sealing reliability.
Solution Approach 2:
The patent modifies the physical parameters of the PTFE seal by adjusting its density, thickness, and cross-sectional shape to optimize performance under extreme temperatures. By changing these parameters, the seal maintains its sealing effectiveness and structural stability without requiring complex multi-component designs, thus achieving both cost-effectiveness and reliability.
2Device complexity
If a simple seal structure is used, then the device complexity is reduced, but the sealing performance deteriorates due to increased wear and pressure-induced leaks
Solution Approach 1:
The patent designs the seal with a dynamic cross-sectional shape that can deform and adapt under operating conditions. The seal's geometry allows it to self-adjust and maintain optimal contact with the plunger shaft surface even under varying pressure and wear conditions, providing sustained sealing performance without requiring complex multi-part structures.
Solution Approach 2:
The patent incorporates a pre-compression design where the seal is installed with initial compression force to compensate for future wear. This beforehand cushioning ensures that the seal maintains adequate contact pressure throughout its service life, preventing pressure-induced leaks while keeping the structure simple and single-piece.
3Reliability
If multiple peripheral parts (seal washer, snap ring) are used to secure the seal, then the sealing reliability is improved, but the manufacturing cost and device complexity increase
Solution Approach 1:
The patent integrates the functions of the seal, seal washer, and snap ring into a single monolithic sealing component. This merged structure incorporates all necessary sealing and retention features within one piece, eliminating the need for multiple separate parts while maintaining or improving sealing reliability through optimized internal geometry and material distribution.
Solution Approach 2:
The patent designs the single-piece seal to perform multiple functions simultaneously: providing the primary sealing barrier, maintaining structural integrity under pressure, and securing itself to the plunger shaft without additional fasteners. This multi-functional design reduces part count while enhancing overall sealing reliability through integrated functionality.
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 effectively prevents water leakage under intense environmental conditions, improves durability, and reduces manufacturing costs by simplifying the structure and ensuring reliable sealing, allowing for mass production with minimal quality variations and reduced leakages.
Implementation Method 1
a tension spring (20) elastically supporting the shaft sealing portion (21) in close contact with the rear side of the shaft scaling portion (13)
Implementation Method 2
a space (22) with a side open is defined inside the seal (17) so that a shaft sealing portion (21) being in close contact with the plunger shaft (13) can be pressed to the plunger shaft (13) by pressure of a coolant flowing in the space (22)
Data Source
AI summary
A valve for controlling the temperature of a coolant to flow into a fuel cell stack to provide the optimum level of coolant at the appropriate temperature in order to keep the operation of the fuel cell stack stable is provided. In particular, new type of seal that can achieve maximum sealability with minimized friction force on a plunger shaft by changing the shape and structure of a seal for sealing the plunger shaft. As such, the valve provides a coolant control valve for a fuel cell stack in a fuel cell vehicle which can improve durability in addition to preventing water leakage and can contribute to reducing the manufacturing cost via reduction of the number or parts and simplification of the structure by removing peripheral parts all while sufficiently sealing the valve.