Glow Plug Contact Element Segmentation for Tip Breakage
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Solution Overview
Problem
Glow plugs experience breakage of the ceramic heater tip during operation, leading to significant damage due to the existing design limitations.
Innovation Solution
A glow plug design featuring a contact element manufactured with high precision, allowing for precise positioning and connection to the glow pencil, with options for pressing, shrink fitting, brazing, or soldering, minimizing the risk of breakage by using independent components optimized for specific functions and reducing surface area for brazing or soldering, thus preventing encapsulated cavities and crack nuclei.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the glow plug uses a conventional design where the sleeve contacts the glow pencil tip, then the structure is simple, but the ceramic heater tip can break off during operation causing heavy consequential damage
Solution Approach 1:
The glow plug is divided into functionally independent components: a contact element for electrical connection, a sleeve for mechanical protection, and a glow pencil for heating. The contact element is separated from the sleeve, allowing each component to be optimized for its specific function without compromising the other.
Solution Approach 2:
The contact function is extracted from the sleeve by introducing a separate contact element. This allows the sleeve to focus solely on mechanical protection while the contact element handles electrical connection, reducing the risk of breakage at the critical glow pencil tip.
2Strength
If the contact surface for brazing or soldering is large, then the connection is robust, but air and oxidation products can adhere to the surface causing harmful influences on the brazing or soldering process
Solution Approach 1:
The brazing or soldering process is performed in an inert atmosphere using argon gas. The contact element design allows complete immersion in the inert gas, preventing air and oxidation products from adhering to the contact surface during the joining process.
Solution Approach 2:
The contact element features a narrowing section that enables dynamic control of the brazing or soldering process. The reduced surface area at the narrowing section minimizes air adhesion while still providing sufficient area for strong mechanical and electrical connection.
3Manufacturing precision
If the contact element is manufactured with high precision lathe-cutting, then positioning and connection accuracy is improved, but manufacturing complexity increases
Solution Approach 1:
The contact element is pre-manufactured with high dimensional accuracy through lathe-cutting before assembly. This preliminary precision manufacturing ensures proper positioning and alignment during subsequent assembly operations, reducing the need for complex adjustment procedures.
Solution Approach 2:
The contact element incorporates a narrowing section with specific geometric contours that facilitate precise positioning. The curved and tapered surfaces enable accurate alignment with the glow pencil during assembly, achieving high positioning accuracy through geometric design rather than complex machining.
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 design reduces the risk of breakage by ensuring tight, clean connections free from encapsulated cavities and crack nuclei, enhancing the durability and reliability of the glow plug.
Implementation Method 1
The contact element is brazed or soldered to the glow pencil
Implementation Method 2
The contact element is brazed or soldered to the glow pencil
Implementation Method 3
Small brazing and soldering surfaces can be completely immersed by an inert shielding gas at low expenses, for example argon. For this reason, harmful influences of air and oxidation products of evaporating contaminants can be kept away from the brazing or soldering material during the brazing or soldering process
Implementation Method 4
If the contact element is connected to the glow pencil by press-fitting, preferably the aperture angle of the narrowing section of the contact element is smaller than the aperture angle of the tapering pencil section
Data Source
AI summary
The invention relates to a glow plug comprising a housing, a ceramic pencil-type glow element which projects from the housing with a first end and is arranged inside the housing with a second end, a feed line which is arranged in the housing and leads to the pencil-type glow element, and a sleeve-type element which surrounds a section of the pencil-type glow element projecting from the housing. The invention is characterized in that the pencil-type glow element has a section surrounded by the housing which section tapers towards the second end, the pencil-type glow element is encircled by a contact element in the housing, which contact element has a section that narrows towards the second end of the pencil-type glow element, said narrowing section encircling at least a subsection of the tapered section of the pencil-type glow element. The invention further relates to a method for producing said glow plug.