Feedforward Pump Control for Fuel Cell Thermal Management
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Solution Overview
Problem
Current thermal sub-systems for fuel cell systems rely on unreliable and costly flow sensors to control cooling fluid flow, which are large and heavy, making them inefficient for maintaining optimal operating temperatures in fuel cell stacks.
Innovation Solution
A feed-forward control algorithm is employed to determine the desired pump speed for the cooling fluid flow in the thermal sub-system, calculating the Reynolds number, pressure loss number, and delivery head value based on system parameters, eliminating the need for flow sensors by using a by-pass valve and temperature sensors to maintain optimal temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If flow sensors are used to control cooling fluid flow, then flow measurement precision is improved, but device complexity, weight, and cost increase
Solution Approach 1:
The patent removes the flow sensor from the system entirely and replaces it with a feedforward control algorithm that calculates the required pump speed based on thermal model parameters, eliminating the source of complexity, weight, and cost associated with flow sensors
Solution Approach 2:
The patent replaces the mechanical flow sensor with a computational feedforward control algorithm that uses temperature measurements and thermal models to determine the appropriate cooling fluid flow rate, substituting physical measurement with mathematical calculation
2Measurement precision
If flow sensors are used to control cooling fluid flow, then flow measurement precision is improved, but system weight increases
Solution Approach 1:
The patent extracts and removes the flow sensor from the system, eliminating its weight contribution entirely while maintaining flow control capability through the feedforward algorithm based on thermal requirements
3Measurement precision
If flow sensors are used to control cooling fluid flow, then flow measurement precision is improved, but cost increases
Solution Approach 1:
The patent extracts the flow sensor from the system architecture, eliminating the need to purchase, install, and maintain expensive flow sensing equipment while achieving equivalent or superior control through the feedforward algorithm
Solution Approach 2:
The patent replaces expensive, complex flow sensors with inexpensive temperature sensors and computational algorithms, using cheaper components to achieve the desired control function
4Device complexity
If feedforward control algorithm is used to control pump speed, then device complexity is reduced, but temperature control precision may worsen
Solution Approach 1:
The patent combines feedforward control with feedback from temperature sensors, using the temperature measurements to adjust and refine the pump speed commands, ensuring precise temperature control while maintaining the simplicity of the overall system
Solution Approach 2:
The feedforward control algorithm performs preliminary action by calculating the required pump speed in advance based on the thermal model and current operating conditions, allowing the system to proactively maintain optimal temperature rather than merely reacting to temperature deviations
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 allows for precise control of cooling fluid flow without the need for flow sensors, reducing system size, weight, and cost while maintaining optimal fuel cell stack temperatures, enhancing system efficiency and durability.
Implementation Method 1
the cooling fluid collects the stack waste heat
Implementation Method 2
the cooling fluid collects the stack waste heat
Implementation Method 3
the cooling fluid is directed through a pipe or hose from the stack to the radiator where it is cooled by ambient air either forced through the radiator from movement of the vehicle or by operation of the fan
Implementation Method 4
the cooling fluid is directed through a pipe or hose from the stack to the radiator where it is cooled by ambient air
Data Source
AI summary
A thermal sub-system for a fuel cell system that employs an algorithm using feed-forward control. The algorithm calculates a Reynolds number based on the velocity of the cooling fluid, a diameter of a coolant loop pipe and a kinematic viscosity (temperature) of a cooling fluid. The algorithm also uses a pressure loss number based on the Reynolds number and a position of a by-pass valve. The algorithm also defines a pressure loss value based on the pressure loss number, the density of the cooling fluid and the velocity of the cooling fluid. The algorithm then calculates a delivery head value based on the pressure loss value, the fluid density and a gravitational acceleration. The algorithm then uses the delivery head value and a predetermined set-point value of the volume flow to determine a desired pump speed based on the current operating parameters of the system.