Exhaust Gas Sensor Carrier Bushing Anti-Twist Mount
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Solution Overview
Problem
Existing exhaust system designs face issues with the short service life of sensors and injection nozzles due to threaded connections, which can lead to costly replacements and leaks when attempting to achieve optimal positioning for measurement or injection, and lack of visibility for determining the rotational position of these components.
Innovation Solution
A carrier bushing with a detachable connection that ensures a defined rotational position, utilizing an anti-twist device and form-fitting means to securely hold the sensing or injecting means, allowing for easy replacement and protection against external damage, while minimizing axial overhang and ensuring optimal alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a threaded connection is used to mount sensors or injection nozzles, then the components can be securely fixed, but the entire housing or pipe must be replaced if the threaded connection is damaged, leading to high replacement costs
Solution Approach 1:
The mounting system is divided into separate components: a receiving bushing that remains permanently mounted in the housing, and a carrier bushing with the sensor or injection nozzle that can be independently removed and replaced. This segmentation allows replacement of only the sensor assembly rather than the entire housing or pipe, reducing replacement costs while maintaining secure fixation through the threaded connection between the receiving bushing and carrier bushing.
2Productivity
If the sensor or injection nozzle is positioned at an inclined angle for optimal measurement or injection, then operational efficiency is improved, but the rotational position cannot be determined from the outside, making alignment verification difficult
Solution Approach 1:
A mark is provided on the carrier bushing that indicates the rotational position of the sensor or injection nozzle. This visual mark allows technicians to verify the correct inclined alignment position from the outside during installation and maintenance, making it possible to confirm proper operational positioning without disassembly or complex measurement tools.
3Manufacturing precision
If the sensor housing is axially braced with a clamping ring, then axial positioning is improved, but the sensor housing may rotate during clamping ring attachment, resulting in undefined rotational position
Solution Approach 1:
The carrier bushing is designed with an asymmetric flat area on its outer circumference that corresponds to a matching asymmetric feature on the receiving bushing. This asymmetric geometry prevents rotation during the clamping process and ensures the sensor or injection nozzle achieves the correct inclined rotational position. The asymmetric features work together to define both axial and rotational positioning simultaneously, eliminating the rotation problem associated with symmetric clamping rings.
Data Source
Figure 1
Figure 2
AI summary
The exhaust gas guiding housing (1) or pipe has an internal chamber (12), nitrogen oxides sensor (22) or injecting unit like a injector nozzle, which extends partly, and a carrier bushing (6) or pipe connected with the housing in a detachable or non-detachable manner for the nitrogen oxides sensor or the injecting unit. A support bushing (20) supports the nitrogen oxides sensor or the injecting unit, inserted in a defined rotating position partly in the carrier bushing and is held axially and in torque proof manner by a detachable connection.