Diesel Fuel Heater PTC Element Assembly Guide

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Solution Overview

Problem

Existing heating devices for diesel fuel, particularly those using PTC heating elements, face difficulties in assembly due to the complex arrangement of PTC heating elements between heat-conducting bodies, which complicates the fixing process within a tubular plastic housing.

Innovation Solution

A plastic tubular housing with an internal guide device allows PTC heating elements to be axially inserted and fixed using a spring device that prestresses the heat transfer device, simplifying assembly and ensuring precise positioning, while also providing a clamping effect to secure the elements against temperature fluctuations and unwanted displacement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If PTC heating elements are clamped between two heat-conducting bodies and fixed in a tubular plastic housing, then reliable thermal contact is achieved, but assembly becomes difficult and complex

Engineering Contradiction:
Improvethermal contact reliabilityVSAvoidassembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the PTC heating element and heat transfer device into a single integrated assembly unit. The heating element is embedded within the heat transfer device structure, allowing them to be installed together as one component rather than separately clamping the heating element between two bodies. This merging reduces assembly steps and complexity while maintaining reliable thermal contact.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The heating element is pre-positioned and secured within the heat transfer device before the entire assembly is installed into the housing. This preliminary arrangement ensures proper alignment and thermal contact are established during manufacturing, simplifying the final installation process and reducing assembly complexity.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If PTC heating elements are clamped between heat-conducting bodies, then secure positioning is achieved, but manufacturing cost increases

Engineering Contradiction:
Improveelement positioning stabilityVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The integration of the heating element within the heat transfer device structure eliminates the need for separate clamping mechanisms and multiple fixing components. This reduces the total part count and assembly operations required, directly lowering manufacturing costs while maintaining secure positioning through the integrated design.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The heat transfer device appears to utilize thin-walled or flexible structural elements that can adapt to secure the heating element in place without requiring rigid, complex fixing mechanisms. This approach reduces material costs and manufacturing complexity while maintaining adequate positioning stability.

Inventive Principle:
Principle #30Flexible shells and thin films

3Adaptability or versatility

If multiple components are assembled in a tubular housing, then functional requirements are met, but assembly time increases

Engineering Contradiction:
Improvefunctional capabilityVSAvoidassembly time
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

By combining the PTC heating element and heat transfer device into a single pre-assembled unit, the number of separate components that need to be individually installed into the tubular housing is reduced. This merging of components directly decreases assembly time while the integrated design maintains all necessary functional capabilities for heating and heat transfer.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The heating element and heat transfer device are pre-assembled and pre-positioned correctly during manufacturing, so that during final installation, the entire assembly is installed as one unit. This preliminary preparation eliminates time-consuming alignment and positioning steps that would otherwise be required during assembly.

Inventive Principle:
Principle #10Preliminary action

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 design simplifies the assembly process, reduces manufacturing costs, and ensures reliable heat transfer and uniform fuel temperature, as the spring device also acts as a turbulator to enhance fuel mixing and maintain element positioning.

Implementation Method 1

PTC heating elements which have posistor thermistors which have a positive temperature coefficient

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

a heat transfer device in thermal contact therewith

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP2072795B1Heating device for fuel
Publication Date: 2012.09.19 MAHLE INT GMBH
  • EP2072795B1 patent drawingFigure 1~2
  • EP2072795B1 patent drawingFigure 3a~3c
  • EP2072795B1 patent drawingFigure 4~6

AI summary

A diesel fuel heater (1) has a PTC heating element (5) coupled to a heat transfer interface (6) with two elements (7, 7') located in a tubular plastic (2) housing. During operation, diesel fuel flows through the housing and around the heat transfer interface. One inner face of the tubular housing has an axial assembling guide for the PTC heater and interface. sind. The interface unit (6) is retained in the guide by a discrete spring assembly.