Integrated Air Cut-Off Valve Module for Fuel Cell Stack
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Solution Overview
Problem
In fuel cell vehicles, existing air cut-off valves increase component size and complexity, leading to unnecessary reactions when stopped and hydrogen concentration exceeding regulation standards during startup, due to air leakage and hydrogen discharge.
Innovation Solution
A compact air cut-off valve module with a sub housing, main housing, and valve plates, driven by a motor with a gear set, that obstructs air paths when stopped and partially opens for bypassing air during startup to reduce hydrogen concentration in exhaust gas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If air cut-off valves are disposed on air supply pipe and air discharge pipe separately with own drivers, then air leakage is blocked, but component size and structural complexity increase
Solution Approach 1:
The patent combines two separate air cut-off valves into a single integrated valve assembly that controls both the air supply pipe and air discharge pipe. This unified structure reduces component count and simplifies the overall system while maintaining the ability to block air leakage in both pipes simultaneously, thereby resolving the contradiction between reliability and structural complexity.
Solution Approach 2:
The integrated valve assembly performs multiple functions: it controls air flow in both the supply and discharge pipes, provides sealed closure for both paths, and enables coordinated operation through a single actuation mechanism. This multi-functionality achieves effective air leakage prevention without requiring separate complex valve systems for each pipe.
2Ease of manufacture
If air cut-off valves are separated from the stack, then maintenance is easier, but air between valves and stack causes unnecessary reactions
Solution Approach 1:
The valve assembly is designed to be pre-installed directly on the stack with integrated sealing structures that eliminate gaps before operation begins. This preliminary positioning ensures that no air can infiltrate between the valves and stack during operation, preventing unnecessary reactions while maintaining a configuration that remains accessible for maintenance.
Solution Approach 2:
The patent introduces sealing elements as intermediary components between the valve assembly and the stack. These seals act as mediators that prevent air infiltration through the interface, eliminating the harmful effect of air leakage while preserving the structural design that allows for ease of installation and maintenance.
3Productivity
If air cut-off valves are opened during startup, then air supply is enabled, but hydrogen-containing air is discharged exceeding regulation standards
Solution Approach 1:
The patent implements a staged valve opening sequence during startup: first the air supply valve opens to enable air supply to the stack, then after a delay period allowing the stack to stabilize, the air discharge valve opens to begin hydrogen discharge. This periodic, sequential action enables air supply while controlling hydrogen discharge timing to meet regulatory standards.
Solution Approach 2:
The air supply valve opens in advance before the discharge valve during startup. This preliminary action establishes proper air flow through the stack first, creating conditions that allow controlled hydrogen discharge afterward without exceeding concentration limits, thereby enabling productivity while managing harmful emissions.
Data Source
AI summary
An air cut-off valve module and a control method thereof is provided. The air cut-off valve module has a structure in which valve plates and driving mechanisms thereof are formed as one module, and is mounted in a stack. Thus, components related to the air cut-off valve are constructed as a compact module. Furthermore, a bypass flow path is formed to dilute exhaust gas of the stack, thereby reducing the concentration of hydrogen.