Sealed Metal-Foil Electric Heater for Chemically Aggressive Vehicle Fluids
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Solution Overview
Problem
Existing electric heaters for motor vehicles face challenges in adequate insulation and material compatibility when heating liquids like water and urea or water and ethylene glycol solutions, leading to material degradation and high costs.
Innovation Solution
The design features metal layers sealed to prevent contact with polymeric layers, with external coatings for chemical resistance, and includes PTC layers for temperature regulation, allowing efficient heating of frozen substances without degrading materials, and utilizing laser welding for assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polymeric layers are used to insulate the heating element from the liquid, then insulation is provided, but the polymeric materials degrade when they come into contact with solutions of water and urea or water and ethylene glycol
Solution Approach 1:
The insulation system is divided into two separate segments: polymeric layers for thermal insulation and metal layers for chemical protection. The metal layers are hermetically sealed to prevent contact between the liquid and polymeric layers, while the polymeric layers provide thermal insulation without being exposed to degrading chemicals.
Solution Approach 2:
Metal layers act as intermediary barriers between the liquid and polymeric layers. These metal layers are chemically resistant to solutions of water and urea or water and ethylene glycol, and they hermetically seal the polymeric layers, preventing direct contact between the liquid and polymeric materials.
2Reliability
If suitable materials are selected to prevent degradation, then material compatibility is achieved, but the cost increases
Solution Approach 1:
The heater employs a composite structure combining polymeric layers and metal layers, each material selected for its specific properties. The polymeric layers provide thermal insulation, while the metal layers provide chemical resistance and hermetic sealing. This composite approach allows the use of cost-effective materials optimized for their specific functions rather than requiring expensive materials that simultaneously provide both insulation and chemical resistance.
3Reliability
If the heating element is well-insulated from the liquid, then material protection is achieved, but heat transmission efficiency may be reduced
Solution Approach 1:
The heater structure applies different properties to different parts: the polymeric layers provide thermal insulation where needed, while the metal layers provide thermal conduction at the surfaces in contact with the liquid. This local differentiation of material properties allows simultaneous achievement of material protection and efficient heat transmission.
Solution Approach 2:
The composite structure of polymeric layers combined with metal layers creates a system where thermal insulation and thermal conduction coexist. The polymeric layers insulate the heating element from the liquid, while the metal layers efficiently transmit heat to the liquid, optimizing both material protection and heat transmission efficiency.
4Reliability
If metal layers are hermetically sealed to prevent contact, then chemical resistance is improved, but device complexity increases
Solution Approach 1:
The metal layers are implemented as thin, flexible foils that can be hermetically sealed around the polymeric layers. This approach achieves chemical resistance and hermetic sealing without requiring complex rigid structures, maintaining relative simplicity in the heater design while providing effective protection.
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 provides effective insulation and compatibility, optimizing heat transmission while preventing material degradation, allowing for efficient and cost-effective heating of liquids and frozen substances, including solutions like water and urea or ethylene glycol.
Implementation Method 1
heaters may be used, provided with a heating element which generates heat by means of the Joule effect
Implementation Method 2
the heating metal sheet, or heating track, may be optionally provided with at least one PTC layer (PTC, Positive Temperature Coefficient), i.e., the resistivity of which increases with the increase of the temperature
Implementation Method 3
it is preferable to weld the metal layers to each other by means of laser welding
Data Source
Figure 1~2a
Figure 3~4
Figure 5~6
AI summary
An electric heater (1, 1') for heating a liquid or frozen substance in a motor vehicle, in particular for heating electric car batteries or an HVAC system or for a system for reducing the environmental pollution of the motor vehicle; the electric heater (1, 1') comprising: - a metal sheet (2) adapted to generate heat when it is crossed by an electric current; - two polymeric layers (3, 4) between which the metal sheet (2) is arranged; - two metal layers (5, 6), between which the two polymeric layers (3, 4) are arranged; wherein the two metal layers (5, 6) are hermetically sealed to each other, defining a casing which prevents the substance to be heated from coming into contact with the two polymeric layers (3, 4) and with the metal sheet (2); wherein there is provided a plurality of metal flaps (7) extending transversely from an external face (61 ) of at least one metal layer (6) of said two metal layers (5, 6).