PTC Heater Housing and Shielding for High-Voltage EMI Control

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Solution Overview

Problem

Existing electrical heating devices for motor vehicles face challenges in high-voltage operations, particularly in ensuring safe and effective heat dissipation and reducing electromagnetic interference, especially when used in modern diesel engines with reduced heat output and in high-power applications.

Innovation Solution

The electrical heating device features a plastic housing with a conductor element made from a metal strip, forming a comb-like structure with claws that connect and shield heat-emitting elements, ensuring electrical insulation and grounding, which reduces electromagnetic interference and enhances safety by preventing short circuits and detecting leakage currents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a metal housing is used for electrical heating devices, then mechanical strength and structural stability are improved, but electromagnetic interference increases and electrical insulation becomes more complex

Engineering Contradiction:
Improvemechanical strengthVSAvoidelectromagnetic interference
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The patent introduces a plastic housing as an intermediary material between the electrical heating elements and the external environment. This plastic housing provides both mechanical structural support and electrical insulation, while also acting as an electromagnetic shield to reduce electromagnetic interference. The housing completely surrounds the heating block and conductor tracks, creating an isolated environment that prevents electromagnetic radiation while maintaining structural integrity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If insulation layers are added on conductor tracks for high-voltage operation, then electrical safety is improved, but device complexity and manufacturing difficulty increase

Engineering Contradiction:
Improveelectrical safetyVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges multiple functions into the housing structure: mechanical support, electrical insulation, and electromagnetic shielding. The housing is designed as an integrated component that completely surrounds the heating block and conductor tracks, eliminating the need for separate insulation layers on the conductor tracks. The heating block itself serves as the primary insulation barrier, with the housing providing additional protection and shielding in a unified structure.

Inventive Principle:
Principle #5Merging (Combining)

3Productivity

If heat-emitting elements are arranged in parallel layers against heat-generating elements, then heat dissipation efficiency is improved, but electrical insulation requirements become more stringent

Engineering Contradiction:
Improveheat dissipation efficiencyVSAvoidelectrical insulation
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The heating block serves as an intermediary structure between the heat-generating conductor tracks and the heat-emitting elements. This heating block provides both thermal contact for efficient heat transfer and electrical insulation to prevent short circuits. The block completely surrounds the conductor tracks, allowing heat-emitting elements to be arranged in parallel layers against it, achieving high heat dissipation efficiency while maintaining adequate electrical insulation through the intermediate heating block structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 shields both the heating block and control components, reducing electromagnetic interference and ensuring safe operation under high-voltage conditions, while allowing for efficient heat dissipation and detection of potential faults, thus improving the reliability and safety of the electrical heating device.

Implementation Method 1

at least one PTC element, on the opposite side surfaces of which lie electrical conductor tracks through which the PTC element is energized

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

heat-emitting elements arranged in parallel layers... held applied to opposite sides of the heat-generating element in order to dissipate the heat generated

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

dissipate the heat generated by the heat-generating element to the medium to be heated

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 4

the housing is made of plastic... electrical insulation provided between the heat-generating and the heat-emitting element

Methodology Applied
Scientific EffectElectrical insulation: Dielectric

Implementation Method 5

The heat-emitting elements, which are electrically connected to one another and decoupled from the current-carrying paths, act as a shield

Methodology Applied
Scientific EffectElectromagnetic shielding: Faraday Cage

Data Source

PatentEP2299201B1Electric heating device
Publication Date: 2012.08.29 EBERSPACHER CATEM GMBH & CO KG
  • EP2299201B1 patent drawingFigure 1
  • EP2299201B1 patent drawingFigure 2
  • EP2299201B1 patent drawingFigure 3

AI summary

The present invention relates to an electrical heating device, in particular for a motor vehicle, having a housing (1) in which at least one heat-generating element (4) with at least one PTC element (10) and electrical Conductor tracks (11, 12) and a plurality of heat-emitting elements (3) arranged in parallel layers are accommodated, which are held applied to opposite sides of the heat-generating element (4) with the interposition of electrical insulation (23). An electrical heating device according to the present invention that meets the practical requirements in an improved manner, particularly in the case of high-voltage operation, has at least one conductor element (10) which electrically connects a number of heat-emitting elements (3) to one another.