Fuel Cell Cathode Pressure Control Without Injector Noise
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Solution Overview
Problem
Fuel cell systems using an oxygen tank face noise issues due to frequent operation of injectors, which are necessary for regulating internal pressure in the fuel cell stack, leading to hitting noise from the needle's movement.
Innovation Solution
A fuel cell system that replaces the injector with a stop valve and regulator, utilizing an oxygen tank and including an oxygen leakage check technology, allowing for quiet operation by regulating cathode internal pressure without the need for a needle-based injector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If an injector is used to regulate cathode internal pressure, then pressure control is achieved, but hitting noise is generated due to frequent needle movement
Solution Approach 1:
The patent removes the injector component entirely from the oxygen supply system. Instead of using an injector with a moving needle to regulate oxygen flow to the cathode, the system uses a combination of an oxygen tank with pressure regulator and a check valve. This extraction of the noisy injector component eliminates the hitting noise while maintaining pressure control functionality through alternative means.
Solution Approach 2:
The patent replaces the mechanical injector system (with solenoid and moving needle) with a passive pressure regulation system using a pressure regulator and check valve. The pressure regulator uses a diaphragm and spring mechanism to maintain constant pressure without rapid mechanical movement, while the check valve provides one-way flow control. This substitution eliminates the solenoid-actuated needle movement that causes hitting noise.
2Ease of operation
If an injector is used for oxygen supply, then oxygen flow regulation is achieved, but system complexity increases due to solenoid and needle components
Solution Approach 1:
The patent extracts and removes the complex injector assembly (solenoid, needle, spring, housing) from the oxygen supply system. The functionality of oxygen flow regulation is achieved through simpler components: a pressure regulator with diaphragm and adjusting screw, and a check valve with simple disc or ball mechanism. This reduction in component complexity while maintaining operational capability.
3Stability of the object's composition
If frequent injector operation is used to maintain pressure, then pressure stability is achieved, but noise generation increases
Solution Approach 1:
The patent implements continuous pressure regulation through the pressure regulator's diaphragm mechanism, which continuously adjusts oxygen flow to maintain constant cathode pressure without intermittent cycling. The check valve provides continuous one-way flow control. This continuous action maintains pressure stability without the repeated start-stop operation of an injector that generates noise.
Solution Approach 2:
The patent replaces the solenoid-actuated mechanical injector with a pressure-regulated flow control system using elastic diaphragm and spring mechanisms. These components respond continuously to pressure changes without rapid mechanical movement or impact, eliminating noise while maintaining pressure stability through passive regulation.
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 system achieves quietness and effective oxygen leakage detection, maintaining internal pressures within predetermined ranges and ensuring efficient operation by using valves and regulators instead of injectors, thereby reducing noise and enhancing system reliability.
Implementation Method 1
an oxygen regulator disposed in the oxygen pipe and configured to regulate a flow rate of oxygen to be supplied from the oxygen tank to a cathode of the FC stack
Implementation Method 2
a fuel cell stack (FC stack)
Data Source
AI summary
A fuel cell system includes: a fuel cell stack; an oxygen tank; an oxygen pipe connecting the fuel cell stack and the oxygen tank; an oxygen regulator disposed in the oxygen pipe and configured to regulate a flow rate of oxygen to be supplied from the oxygen tank to a cathode of the fuel cell stack; an oxygen stop valve disposed in the oxygen pipe; and a controller configured to execute, when activating or stopping the fuel cell stack: a first process of opening the oxygen stop valve and the oxygen regulator; a second process of closing the oxygen stop valve and the oxygen regulator when a cathode internal pressure reaches a predetermined first cathode pressure; and a third process of outputting a signal indicating occurrence of oxygen leakage when the cathode internal pressure after a predetermined period is lower than a predetermined second cathode pressure.