Fuel Cell Coolant Pump Speed Control to Prevent Cavitation
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Solution Overview
Problem
Fuel cell systems face challenges in maintaining cooling efficiency and preventing cavitation in the coolant circulation pump, leading to potential malfunctions and reduced durability due to inadequate coolant pressure regulation and excessive stress on separators.
Innovation Solution
A fuel cell system incorporating a pressure regulating mechanism that independently regulates coolant pressure, in conjunction with a pump controller to control the coolant circulation pump's rotation speed based on heat release amounts, sets an upper limit for the pump's speed to prevent cavitation and equalize coolant and reactant gas pressures, thereby reducing stress on separators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the rotation speed of the coolant circulation pump is increased to enhance cooling capacity, then cooling efficiency is improved, but cavitation occurs in the pump and pressure differences cause stress on separators
Solution Approach 1:
The patent applies dynamics by making the pump rotation speed adjustable and controllable based on operating conditions. The pump controller dynamically adjusts the rotation speed to match the heat release amount, preventing both insufficient cooling and excessive speed that causes cavitation. This dynamic control resolves the contradiction between cooling efficiency and pump reliability.
Solution Approach 2:
The patent changes the operational parameters by setting the pump rotation speed within a specific range (0-3000 rpm) based on heat release amount and coolant temperature. By controlling the rotation speed parameter rather than operating at fixed high speed, the system achieves adequate cooling while preventing cavitation and reducing stress on separators.
2Productivity
If the rotation speed of the coolant circulation pump is increased to match heat release amount, then cooling capacity is improved, but cavitation occurs at the pump inlet
Solution Approach 1:
The patent implements feedback control where the pump controller continuously monitors coolant temperature and heat release amount, then adjusts the pump rotation speed accordingly. This feedback mechanism ensures the pump operates at optimal speed to provide sufficient cooling capacity while preventing conditions that lead to cavitation.
Solution Approach 2:
The system uses dynamic speed adjustment rather than fixed high-speed operation. The pump controller dynamically sets the rotation speed based on actual cooling requirements, enabling the system to achieve necessary cooling capacity without excessive speed that would cause cavitation at the pump inlet.
3Strength
If the pressure of coolant is increased to match reactant gas pressure, then stress on separators is reduced, but pump rotation speed must be increased which causes cavitation
Solution Approach 1:
The patent changes the approach by controlling pressure through rotation speed management rather than simply increasing speed. By limiting the rotation speed to a maximum of 3000 rpm and adjusting it based on heat release amount, the system achieves adequate coolant pressure to reduce separator stress while preventing cavitation that would occur at higher speeds.
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 solution effectively suppresses cavitation and maintains cooling efficiency while extending the lifespan of the fuel cell by reducing pressure differences and stress on separators, ensuring reliable operation and improved durability.
Implementation Method 1
a coolant circuit provided with a coolant circulation pump (45) and a cooler (47) and configured to circulate a coolant to be supplied to the coolant channel (78)
Implementation Method 2
a cooler (47) and is configured to circulate a coolant to be supplied to the coolant channel (78)
Implementation Method 3
A fuel cell generates electricity in accordance with an electrochemical reaction between anode gas, such as hydrogen gas, and cathode gas, such as oxygen (air)
Implementation Method 4
The supercharger is configured to apply pressure to cathode gas and supply the cathode gas to the fuel cell
Data Source
AI summary
A fuel cell system includes a fuel cell, a supercharger, a coolant circuit, a pump controller, and a pressure regulating mechanism. The supercharger applies pressure to cathode gas and supplies the cathode gas to the fuel cell. The coolant circuit has a coolant circulation pump and a cooler and circulates a coolant to be supplied to a coolant channel in the fuel cell. The pressure regulating mechanism regulates coolant pressure in the fuel cell. The pump controller controls a rotation speed of the pump in accordance with a heat release amount required by the fuel cell and controls the pump in a range lower than or equal to an upper limit for the rotation speed set based on one or both of inlet coolant pressure of the pump or a correlation value thereof and an inlet coolant temperature of the pump or a correlation value thereof.