Exhaust Gas Sensor Glass Insulator Molding
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Solution Overview
Problem
Graphite residue from mold elements can impair the electrical insulating properties of glass insulators in sensors used in internal combustion engines, leading to potential corrosion and reduced durability.
Innovation Solution
Using insulating elements with high electrical resistance, such as ceramic materials, in contact with the glass solder during the molding process to form glass insulators, which remain inside the sensor, providing corrosion protection and maintaining the insulating properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If graphite mold elements are used for shaping glass insulators during finish molding, then the glass insulators can be formed at predetermined temperature and time, but graphite can come loose from the mold elements and become deposited on the glass insulator, negatively impairing the electrical insulating properties
Solution Approach 1:
A coating layer is applied to the graphite mold element that acts as an intermediary between the graphite and the glass insulator. This coating prevents graphite particles from transferring to the glass insulator while still allowing the glass to be properly formed. The coating serves as a barrier that mediates the interaction between the mold and the insulator, eliminating the harmful graphite deposition.
Solution Approach 2:
The patent employs a coating on the graphite mold that can be replaced or regenerated. Instead of trying to create a perfectly permanent non-graphite-releasing mold, the solution accepts that the mold surface needs periodic maintenance. The coating is designed to be replaceable, allowing the system to maintain high insulator quality through periodic renewal rather than attempting permanent prevention.
2Reliability
If glass insulators are used to electrically insulate electrodes in the exhaust gas stream, then electrical insulation is provided, but the glass insulators are susceptible to corrosion from the harsh exhaust gas environment, reducing durability
Solution Approach 1:
The patent applies a protective coating layer on the glass insulator surface, creating a composite structure. The core glass insulator provides the essential electrical insulation properties, while the outer coating layer provides enhanced resistance to chemical corrosion from the exhaust gas. This composite approach combines the advantages of both materials: the electrical insulation of glass and the chemical resistance of the coating material.
Solution Approach 2:
The protective coating creates an inert barrier environment between the reactive exhaust gas and the glass insulator surface. This coating layer is selected to be chemically inert or highly resistant to the corrosive components in exhaust gas, effectively creating a protected micro-environment that prevents direct interaction between the harsh gas and the glass insulator, thereby extending its service life.
Data Source
AI summary
Various embodiments include a method for the production of a sensor for an exhaust gas stream of an internal combustion engine, wherein the sensor comprises a first electrode and a second electrode. The method comprises: arranging a glass solder in a mold substantially between and substantially insulating the first electrode and the second electrode; arranging an insulating element in the mold in contact with a free surface of the glass solder; and finish molding the glass solder into a glass insulator together with the insulating element in a predetermined position relative to the first electrode and the second electrode. The insulating element shapes the glass insulator during the finish molding and at least partially isolates the glass insulator from the exhaust gas of the internal combustion engine during a measuring operation of the sensor.