Fuel Cell Liquid Water Estimation via Multi-Parameter Analysis

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing fuel cell systems struggle to accurately estimate the amount of liquid water discharged, as they only account for total water vapor and liquid water based on generated current, lacking precision in liquid water estimation.

Innovation Solution

A fuel cell system that includes a liquid water amount estimation section, which calculates the discharged liquid water amount using generated current, air supply, air temperature, relative humidity, exhaust temperature, and exhaust pressure, along with a valve control system to manage liquid water storage and heat exchanger jetting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the amount of discharged water is estimated only on the basis of the integrated value of the generated current, then the estimation method is simple, but only the total amount of water vapor and liquid water can be estimated, not the liquid water amount specifically

Engineering Contradiction:
Improveliquid water amount estimation accuracyVSAvoidestimation system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the total water discharge estimation into two distinct components: water vapor amount and liquid water amount. By separately calculating each component based on different parameters (current integration for total water, temperature and humidity for vapor condensation), the system achieves precise liquid water estimation without requiring complex additional hardware.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The estimation section performs multiple functions using the same input parameters: it calculates total water amount from current integration, estimates water vapor condensation from temperature and humidity data, and derives liquid water amount by subtracting vapor from total. This multi-functional approach improves precision without proportionally increasing device complexity.

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

2Productivity

If the valve opening degree is controlled based on estimated liquid water amount, then liquid water storage efficiency is improved, but the system requires accurate liquid water estimation capability

Engineering Contradiction:
Improveliquid water storage efficiencyVSAvoidliquid water amount estimation accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The system implements feedback control by continuously monitoring estimated liquid water amount and adjusting the valve opening degree accordingly. The estimation section provides real-time liquid water amount data, which feeds back to the valve control mechanism, enabling dynamic optimization of storage efficiency based on actual discharge conditions.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system changes the control parameter from simple current integration to a comprehensive estimation based on multiple parameters including temperature, humidity, and current. This parameter transformation enables accurate liquid water estimation, which then serves as the basis for optimal valve control and improved storage efficiency.

Inventive Principle:
Principle #35Parameter changes

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

Accurately estimates and manages the discharged liquid water amount, improving storage efficiency and heat exchanger performance by controlling valve opening based on estimated liquid water levels and promoting heat exchange by jetting water to the heat exchanger.

Implementation Method 1

a fuel cell stack at which generation of electricity is carried out by chemical reaction of hydrogen and oxygen

Methodology Applied
Scientific EffectChemical reaction: Fuel Cell

Implementation Method 2

the liquid water that is discharged at the time of generating electricity is stored in a catch tank

Methodology Applied
Scientific EffectWater vapor condensation: Condensation

Data Source

PatentEP3599657B1Fuel cell system with liquid water amount estimating section
Publication Date: 2021.11.10 TOYOTA JIDOSHA KK
  • EP3599657B1 patent drawingFigure 1
  • EP3599657B1 patent drawingFigure 2
  • EP3599657B1 patent drawingFigure 3

AI summary

A fuel cell system includes: a fuel cell stack at which generation of electricity is carried out by chemical reaction of hydrogen and oxygen, and from which water and exhaust are discharged; and a liquid water amount estimation section that estimates an amount of liquid water among the discharged water, based on an amount of current that is generated by the fuel cell stack, an amount of air that is supplied to the fuel cell stack, a temperature of the air, a relative humidity of the air, a temperature of exhaust that is discharged from the fuel cell stack, and a pressure of the exhaust.