Fuel Cell Coolant Flow Path Switching Valve Control

Solution Overview

Problem

The existing fuel cell system struggles with rapid cooling after power generation stops, leading to potential deterioration due to incomplete heat release and inefficient coolant temperature control, especially when the coolant temperature drops below the thermostat valve's switching point.

Innovation Solution

A fuel cell system with a radiator, coolant pump, temperature detection, and a flow path switching valve that directs coolant through a radiator circulation path until a lower temperature threshold is reached, utilizing a thermostat valve with a heater to enhance cooling efficiency and simplify control, while also detecting malfunctions and optimizing coolant circulation based on temperature and time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the thermostat valve is used to control coolant flow based on a fixed switching temperature, then coolant temperature control is simplified, but rapid cooling after power generation stops cannot be achieved when coolant temperature drops below the switching point

Engineering Contradiction:

Improvecoolant temperature controlVSAvoidcooling speed

Core Design Contradiction:

Ease of operationVSSpeed

Solution Approach 1:

The patent applies dynamics by making the flow path switching valve controllable through both temperature signals and timing signals. The valve dynamically adjusts coolant flow based on real-time temperature conditions and elapsed time since power generation stop, enabling rapid cooling when needed while maintaining simple thermostat-based control during normal operation.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent implements feedback by using temperature sensors to continuously monitor coolant temperature and feed this information back to the control unit. The control unit then adjusts the flow path switching valve accordingly, creating a closed-loop control system that achieves rapid cooling when temperature drops below the switching point while maintaining simplicity through automated feedback-based decisions.

Inventive Principle:

Principle #23Feedback

2Productivity

If the coolant circulation path is extended to enable rapid cooling, then cooling efficiency improves, but system complexity and cost increase

Engineering Contradiction:

Improvecooling efficiencyVSAvoidcoolant circulation path

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent applies universality by designing the flow path switching valve to serve multiple functions: it directs coolant flow during normal temperature-based thermostat control, enables rapid cooling mode when temperature drops below the switching point, and can be controlled by both temperature signals and timing signals. This multi-functionality allows rapid cooling capability without adding separate dedicated cooling paths.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the rapid cooling function with the existing thermostat-based coolant circulation system. Instead of creating a separate rapid cooling path, the invention combines both functions through a single controllable flow path switching valve that integrates temperature-based control and time-based control into one unified system.

Inventive Principle:

Principle #5Merging (Combining)

3Device complexity

If the flow path switching valve is controlled solely by temperature, then control simplicity is maintained, but rapid cooling cannot be triggered when temperature drops below thermostat switching point

Engineering Contradiction:

Improvecontrol mechanismVSAvoidfuel cell protection

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent implements feedback by using temperature sensors to continuously monitor coolant temperature and feed this information back to the control unit. The control unit then adjusts the flow path switching valve accordingly, creating a closed-loop control system that achieves rapid cooling when temperature drops below the switching point while maintaining simplicity through automated feedback-based decisions.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent applies preliminary action by having the control unit monitor both temperature and elapsed time since power generation stop. When the temperature drops below the switching point and the predetermined time has elapsed, the control unit proactively triggers rapid cooling mode by controlling the flow path switching valve, preventing potential fuel cell deterioration before it occurs.

Inventive Principle:

Principle #10Preliminary action

4Reliability

If rapid cooling is always enabled, then fuel cell deterioration is prevented, but energy consumption and noise increase during normal operation

Engineering Contradiction:

Improvefuel cell protectionVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies dynamics by making the flow path switching valve controllable through both temperature signals and timing signals. The valve dynamically adjusts coolant flow based on real-time temperature conditions and elapsed time since power generation stop, enabling rapid cooling when needed while maintaining simple thermostat-based control during normal operation.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent implements feedback by using temperature sensors to continuously monitor coolant temperature and feed this information back to the control unit. The control unit then adjusts the flow path switching valve accordingly, creating a closed-loop control system that achieves rapid cooling when temperature drops below the switching point while maintaining simplicity through automated feedback-based decisions.

Inventive Principle:

Principle #23Feedback

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 rapid cooling of the fuel cell to a lower temperature, preventing deterioration and improving cooling efficiency, while reducing costs and noise, and allows for early detection of malfunctions, thus enhancing the system's reliability and user experience.

Implementation Method 1

a radiator that releases heat of coolant that cools the fuel cell

Methodology Applied

Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

utilizing a thermostat valve with a heater to enhance cooling efficiency

Methodology Applied

Scientific EffectHeating: Heating

Implementation Method 3

coolant that cools the fuel cell

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS9786935B2Fuel cell system and fuel cell system control method

Publication Date: 2017.10.10 HONDA MOTOR CO LTD

AI summary

A controller (control portion) of a fuel cell system is provided with a flow path switching control device that switches a thermostat valve (flow path switching valve) so that, after a fuel cell has stopped generating electric power, coolant is supplied to a radiator circulation path until the coolant temperature becomes a second temperature threshold value that is lower than a first temperature threshold value.