Fuel Cell Release Pipe Heating via Waste Heat
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Solution Overview
Problem
Conventional safety valve systems in fuel cell and fuel gas vehicles fail to function under low temperature conditions due to blockages from frozen snow or water, as the release outlets are not designed to operate effectively in such environments.
Innovation Solution
The release pipe and outlet are strategically placed between the fuel cell stack and hydrogen tank, under the vehicle's floor, where they can be heated by waste heat from the fuel cell stack or engine, ensuring the release outlet remains unblocked and functional even in low temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the release outlet is placed in conventional positions, then the safety valve can release hydrogen, but the release outlet may be blocked by frozen snow or water under low temperature conditions
Solution Approach 1:
The patent utilizes the waste heat generated by the fuel cell stack, which would otherwise be discarded, to heat the release outlet and prevent freezing. This converts a harmful waste product (heat) into a beneficial function (preventing blockage), resolving the contradiction between maintaining safety valve reliability and avoiding blockage from frozen snow or water.
Solution Approach 2:
The patent introduces a heat transfer medium (air or fluid) that circulates between the fuel cell stack and the release outlet. This intermediary transfers thermal energy from the heat source to the release outlet, preventing snow and water from freezing and blocking the outlet, thus ensuring reliable safety valve operation in cold conditions.
2Reliability
If the release outlet is positioned to avoid blockages, then the safety valve can function reliably, but the hydrogen release may affect electric wires or other containers
Solution Approach 1:
The patent positions the release outlet in a specific location (between the fuel cell stack and hydrogen tank, under the floor) where it benefits from localized waste heat while directing hydrogen release away from sensitive components. This localized positioning resolves the contradiction by ensuring reliable valve function through heat exposure while preventing hydrogen from affecting electric wires or containers.
3Object-affected harmful factors
If a shielding member is provided to disperse hydrogen, then outside influence is reduced, but the release outlet remains vulnerable to blockage under low temperature conditions
Solution Approach 1:
The patent combines the shielding member function with the thermal protection function by positioning the release outlet within the heated zone of the fuel cell stack. This merging ensures that the outlet is both protected from blockage by freezing and equipped with shielding to disperse hydrogen, resolving the contradiction between reducing outside influence and maintaining reliability under low temperature conditions.
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
This configuration ensures the safety valve can operate reliably by preventing blockages from ice or snow, maintaining the functionality of the release system under various conditions, including low temperatures.
Implementation Method 1
this area is an area to which heat generated in the fuel cell stack is easily transferred so that the waste heat of the fuel cell stack can heat the release outlet
Implementation Method 2
the ventilation may send ventilation air to rearward of the fuel cell box toward the release outlet
Implementation Method 3
a safety valve is employed to release hydrogen to reduce pressure of hydrogen when temperature rises in a hydrogen tank
Implementation Method 4
The safety valve is provided in the vicinity of the hydrogen tank and sealed by metal having low melting point. However, when the metal is melted as the temperature rises in the hydrogen tank, high-pressure gas pushes a plug of the safety valve so as to open the safety valve
Data Source
AI summary
A release outlet (52) of a release pipe (51) of a relief valve (50) is provided in the vicinity of an exhaust outlet (170) of a fuel cell box (39) in a space between a sub-frame (22) and the fuel cell box (39). A ventilating inlet (130) is formed on a front wall (120) of the fuel cell box (39). A fan (180) can send outside air into the fuel cell box (39). A ventilation flow of the outside air which is sent into the fuel cell box (39) passes through and ventilates the fuel cell box (39) so as to cool a fuel cell stack (38). Exhaust air is exhausted rearward from the exhaust outlet (170) of an exhaust duct (160). The release pipe (51) and the release outlet (52) are heated by the exhaust air. Therefore, heating the release pipe (51) and the release outlet (52) can prevent the release outlet (52) from being blocked by snow or ice.