Fuel Cell Excess Hydrogen Flow Control via Sensor Feedback

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Solution Overview

Problem

Current fuel cell systems lack a method to directly measure and manage excess hydrogen flow, leading to inefficiencies and premature aging of fuel cell membranes, resulting in reduced performance and increased costs due to high parasitic loads and pressure losses.

Innovation Solution

A system comprising a controller that mixes two flow streams to form a third stream, which flows through the anode inlet of a fuel cell stack, using sensors and models to compare the excess fuel ratio to a target ratio, and adjusts components like blowers, ejectors, and by-pass valves to maintain optimal conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high fuel flow rates are maintained at the anode to achieve higher excess fuel level, then the excess fuel level is improved, but pressure loss increases and parasitic load increases

Engineering Contradiction:

Improveexcess fuel levelVSAvoidparasitic load

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The system directly measures the excess fuel level using sensors and feeds this information back to the fuel management system. The controller uses this feedback to adjust the fuel flow rate, maintaining the minimum required excess fuel level without unnecessarily high flow rates, thereby reducing parasitic load while ensuring adequate excess fuel is present

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent replaces indirect mechanical estimation methods with direct measurement using sensors (such as pressure sensors or mass flow meters). This substitution enables precise monitoring of excess fuel level, allowing the system to optimize fuel flow rates based on actual measurements rather than relying on mechanical assumptions or conservative high-flow-rate operation

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If high fuel flow rates are maintained at the anode to achieve higher excess fuel level, then the excess fuel level is improved, but pressure loss increases

Engineering Contradiction:

Improveexcess fuel levelVSAvoidpressure loss

Core Design Contradiction:

ReliabilityVSStress or pressure

Solution Approach 1:

The system directly measures the excess fuel level and feeds this information back to the controller. The controller adjusts the fuel flow rate based on this feedback to maintain the minimum required excess fuel level, avoiding unnecessarily high flow rates that would increase pressure loss while ensuring adequate excess fuel is present

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts the fuel flow rate parameter based on the measured excess fuel level. By changing the flow rate parameter to match the actual needs of the fuel cell stack, the system maintains adequate excess fuel while minimizing pressure loss associated with excessively high flow rates

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If minimum excess fuel level is not achieved, then the system operation is simplified, but fuel cell performance decreases and aging increases

Engineering Contradiction:

Improvefuel management complexityVSAvoidfuel cell performance

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The system directly measures the excess fuel level and uses this feedback to automatically adjust fuel flow rates. This feedback mechanism simplifies fuel management by eliminating the need for complex control algorithms or conservative operating margins, while ensuring the fuel cell always operates with adequate excess fuel to maintain performance and minimize aging

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The fuel management system uses direct measurement feedback to self-regulate fuel flow rates. The system automatically maintains the appropriate excess fuel level without requiring complex external control or intervention, thereby simplifying operation while ensuring fuel cell performance and longevity

Inventive Principle:

Principle #25Self-service

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 enables precise control of excess hydrogen flow, reducing parasitic loads, extending fuel cell life, and maintaining optimal performance by accurately managing pressure and flow rates within the fuel cell system.

Implementation Method 1

a first flow stream and a second flow stream mixing to form a third flow stream

Methodology Applied

Scientific EffectFluid mixing:

Implementation Method 2

the physical or virtual sensor may measure pressure across the fuel cell stack

Methodology Applied

Scientific EffectPressure measurement:

Implementation Method 3

The controller may further measure mass flow rate in the first flow stream or the measured mass flow rate in the second flow stream

Methodology Applied

Scientific EffectMass flow rate measurement:

Data Source

PatentUS20230085312A1Systems and methods to measure or control fuel cell stack excess hydrogen flow

Publication Date: 2023.03.16 CUMMINS INC

AI summary

The present disclosure generally relates to systems and methods for determining, managing, and/or controlling excess hydrogen flow in a system comprising a fuel cell or fuel cell stack.