PTC Honeycomb Heater Element for Vehicle Interior

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Solution Overview

Problem

Conventional heaters for vehicle interiors, such as steam compression heat pumps and Joule heat-based systems, face challenges in low outside temperatures and rapid heating requirements, with honeycomb heaters experiencing excessive heat generation and moisture-induced short circuits when used with steam compression heat pumps.

Innovation Solution

A pillar-shaped honeycomb heater element with PTC characteristics and a dense insulating film is developed, utilizing a material with a Curie point above 100°C and additives like barium titanate to prevent short circuits from dew condensation water, while maintaining compactness and efficient heat transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a honeycomb heater is used for heating, then heating efficiency is improved, but excessive heat generation occurs causing safety issues

Engineering Contradiction:

Improveheating efficiencyVSAvoidexcessive heat generation

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent applies parameter changes by utilizing the PTC material's inherent property where electrical resistance increases with temperature. This automatic parameter change prevents excessive heat generation - as the heater reaches optimal temperature, resistance increases and current decreases, naturally limiting further temperature rise without external control mechanisms.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The PTC material provides self-regulating temperature control through its intrinsic resistance-temperature characteristics. The heater element automatically adjusts its electrical resistance based on its own temperature, eliminating the need for external thermostats or control systems to prevent overheating.

Inventive Principle:

Principle #25Self-service

2Ease of operation

If a honeycomb heater is used in humid conditions, then heating function is provided, but moisture causes short circuits reducing reliability

Engineering Contradiction:

Improveheating functionVSAvoidshort circuit prevention

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent employs composite materials by combining PTC ceramic material with organic insulation coatings or sealants. This composite structure provides both the heating function through PTC characteristics and moisture resistance through the insulating coating layer, preventing dew condensation from causing short circuits.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent applies thin film insulation coatings on the honeycomb heater surface to prevent moisture contact. These flexible insulating films create a protective barrier against dew condensation while maintaining the heater's compact structure and heating efficiency.

Inventive Principle:

Principle #30Flexible shells and thin films

3Speed

If rapid heating is required at vehicle start, then heating speed is improved, but energy consumption increases

Engineering Contradiction:

Improveheating speedVSAvoidenergy consumption

Core Design Contradiction:

SpeedVSUse of energy by moving object

Solution Approach 1:

The PTC heater operates in periodic cycles where high power is applied initially for rapid heating, then automatically reduces power as temperature increases and resistance rises. This periodic action pattern enables fast initial heating while minimizing overall energy consumption through automatic power reduction.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The heater utilizes parameter changes in electrical resistance with temperature to automatically adjust power consumption. During rapid heating phase, lower resistance allows high current and power for fast heating; as temperature rises, resistance increases and power automatically decreases, optimizing energy usage.

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

The solution effectively suppresses excessive heat generation and short circuits, enabling rapid and efficient heating of vehicle interiors, even in low temperatures, while maintaining a compact size and safety standards.

Implementation Method 1

a heater using Joule heat generated by electric resistance during conduction of current

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Implementation Method 2

the outer peripheral wall and the partition walls comprise a material having PTC characteristics

Methodology Applied

Scientific EffectPTC characteristics: Thermistor

Data Source

PatentUS20220371405A1Heater element for heating vehicle interior, and heater for heating vehicle interior

Publication Date: 2022.11.24 NGK INSULATORS LTD

AI summary

A heater element for heating a vehicle interior includes a pillar shaped honeycomb structure portion having: an outer peripheral wall; and partition walls arranged on an inner side of the outer peripheral wall, the partition walls defining a plurality of cells, each of the cells forming a flow path from a first end face to a second end face. The outer peripheral wall and the partition walls are made of a material having PTC characteristics. The heater element further includes a dense insulating film that covers at least a part of the pillar shaped honeycomb structure portion.