Fuel Cell Exhaust Mixing With Heated Air to Reduce Water Mist

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Solution Overview

Problem

Fuel cell systems emit water in the form of a mist, or white smoke, which can impair visibility, lead to icing, and be mistaken for malfunction or fire, requiring a cost-effective and passive solution to mitigate these issues.

Innovation Solution

A fuel cell system that mixes exhaust water with heated air from a cooling assembly, using a radiator and airflow generator to dilute and heat the water mist, avoiding or reducing its expulsion through the system exhaust.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If water is expelled directly from the fuel cell exhaust, then the fuel cell system operates simply without additional components, but water mist is emitted which impairs visibility and causes icing

Engineering Contradiction:
Improvesystem complexityVSAvoidwater mist emission
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces heated air as an intermediary substance that mixes with the water-containing exhaust from the fuel cell. This heated air acts as a mediator to raise the temperature of the water droplets, preventing them from condensing into visible mist and reducing the risk of icing, while maintaining system simplicity

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the temperature parameter of the exhaust gas by mixing it with heated air from the cooling assembly. This parameter change (temperature increase) transforms the exhaust from a cold, mist-forming flow into a warm flow that does not produce visible water mist, thereby eliminating the harmful effects without adding complex control systems

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If heated air from the cooling assembly is mixed with the cell exhaust, then water mist is reduced or avoided, but the system requires integration of cooling and exhaust systems

Engineering Contradiction:
Improvewater mist emissionVSAvoidsystem integration
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent merges the cooling assembly and exhaust system into a single integrated configuration where the heated air from the radiator is combined with the cell exhaust. This merging allows the cooling system to serve a dual purpose: both cooling the fuel cell and treating the exhaust to prevent water mist formation, thereby reducing overall system complexity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The cooling assembly is designed to perform multiple functions: it cools the fuel cell through the radiator and simultaneously provides heated air for exhaust treatment. This multi-functionality eliminates the need for separate exhaust heating components, reducing system complexity while effectively reducing water mist emission

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 solution effectively reduces water mist emission, enhances visibility, minimizes icing, and prevents mist from being mistaken for smoke or fire, without requiring active control mechanisms.

Implementation Method 1

the cooling assembly comprises a radiator... which is an example of a heat exchanger, may provide efficient cooling. Typically, the radiator comprises a liquid coolant and is adapted to transfer heat from the coolant to ambient air

Methodology Applied
Scientific EffectHeat exchanger: Heat Exchanger

Implementation Method 2

the cooling assembly comprises an airflow generator for flowing the ambient air through the radiator

Methodology Applied
Scientific EffectForced convection: Forced Convection

Implementation Method 3

the fuel cell system is configured to mix the exhaust mixture of the cell exhaust with heated air of the cooling assembly

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP4629355A1A fuel cell system configured to reduce exhaust water mist and a method of operating a fuel cell system
Publication Date: 2025.10.08 VOLVO CONSTRUCTION EQUIPMENT AB
  • EP4629355A1 patent drawingFigure 1~2
  • EP4629355A1 patent drawingFigure 3~7
  • EP4629355A1 patent drawing

AI summary

A fuel cell system (1) comprising - a cell exhaust (10e) for an exhaust mixture comprising water fluid (15) generated in a fuel cell (10) of the fuel cell system (1), - a cooling assembly (20) for cooling the fuel cell (10) using ambient air (25), and - a system exhaust (1e), wherein the fuel cell system (1) is configured to mix the exhaust mixture of the cell exhaust (10e) with heated air (25h) of the cooling assembly (20) to avoid or reduce water mist (5) being expelled from the system exhaust (1e). A method (100) of operating a fuel cell system.