Inductive Glow Plug for Fuel Cell Heat Leak Reduction

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Solution Overview

Problem

Conventional resistive heating glow plugs in fuel cell systems face issues with heat leaks, temperature variations, and oxidation, leading to reduced reliability and longevity due to thermal stress and potential open circuit conditions.

Innovation Solution

The implementation of electromagnetic induction glow plugs, which use an alternating current (AC) generator to induce eddy currents in a ferromagnetic heating element, providing efficient and oxidation-resistant heating for fuel cell systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional resistive heating glow plugs are used, then heating function is provided, but heat leaks and thermal stress occur leading to reduced reliability

Engineering Contradiction:

ImprovereliabilityVSAvoidheat leaks

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent replaces the conventional resistive heating mechanism with electromagnetic induction heating. The electromagnetic induction glow plug uses an alternating current (AC) generator to induce eddy currents in a ferromagnetic heating element, which generates heat through electromagnetic induction rather than resistive heating. This substitution eliminates the need for direct electrical connections and resistive elements that cause heat leaks and thermal stress, thereby improving reliability while reducing energy loss.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the heating mechanism from resistive heating to electromagnetic induction heating by altering the physical parameters of the heating system. The AC generator produces alternating current at specific frequencies that induce eddy currents in the ferromagnetic material, changing the fundamental heating parameter from resistive heat generation to electromagnetic-induced heat generation. This parameter change reduces thermal stress and heat leaks.

Inventive Principle:

Principle #35Parameter changes

2Duration of action of stationary object

If conventional resistive heating glow plugs are used, then heating function is provided, but oxidation occurs leading to reduced longevity

Engineering Contradiction:

ImprovelongevityVSAvoidoxidation

Core Design Contradiction:

Duration of action of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the conventional resistive heating element with an electromagnetic induction heating system. The heating element in the induction system is not directly connected to electrical leads, eliminating the oxidation-prone electrical connections. The ferromagnetic heating element is heated indirectly through induced eddy currents, protecting it from oxidation and extending its service life.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If conventional resistive heating glow plugs are used, then heating function is provided, but thermal stress occurs leading to potential open circuit conditions

Engineering Contradiction:

ImprovereliabilityVSAvoidthermal stress

Core Design Contradiction:

ReliabilityVSStress or pressure

Solution Approach 1:

The patent substitutes the resistive heating system with an electromagnetic induction heating system. The induction heating element does not require direct electrical connections that are susceptible to thermal stress and open circuit conditions. The alternating current generator induces currents in the heating element without direct contact, eliminating the thermal stress pathways that lead to open circuits in conventional systems.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 enhances the reliability and longevity of fuel cell systems by minimizing heat leaks and thermal stress, while maintaining efficient heating and preventing oxidation of the heating elements, thus improving operational efficiency.

Implementation Method 1

electromagnetic induction glow plugs, which use an alternating current (AC) generator to induce eddy currents in a ferromagnetic heating element

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

induce eddy currents in a ferromagnetic heating element, providing efficient and oxidation-resistant heating

Methodology Applied

Scientific EffectEddy currents: Eddy Currents

Implementation Method 3

heating the fuel/air mixture in a reaction zone of the fuel cell system using heat generated by the heating element

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 4

heating the fuel/air mixture in a reaction zone of the fuel cell system using heat generated by the heating element

Methodology Applied

Scientific EffectThermal radiation: Thermal Radiation

Data Source

PatentUS10930943B2Fuel cell system including inductive heating element and method of using same

Publication Date: 2021.02.23 BLOOM ENERGY CORP

AI summary

A fuel cell system and method of operating the same, the system including: a fuel cell stack and a reaction zone configured to receive a fuel/air mixture; an electromagnetic induction glow plug configured to heat the fuel/air mixture; and an alternating current (AC) generator configured to provide an AC voltage to the glow plug. The glow plug includes a housing extending outside of the hotbox, a heating element disposed in the housing, and a coil coiled around the housing, electrically connected to the AC generator, and configured to inductively heat the heating element.