Threaded Pipe Coupling Leakage Diversion Design
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Solution Overview
Problem
In internal combustion engines, threaded pipe couplings between high-pressure lines and injectors can leak, causing fuel to dilute the motor oil and potentially enter the combustion chambers, leading to engine damage.
Innovation Solution
A threaded pipe coupling design featuring a union nut with a graduated inner bore and indentations, along with sealing features like grooves for O-rings or coated sealing mediums, diverts leaks outside the engine, preventing them from reaching the motor oil by incorporating a connection stub with a male thread and a pipe with a nipple having a sealing face and bearing face with corresponding indentations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a threaded pipe coupling is used between high-pressure line and injector, then connection is established, but leakage occurs that dilutes motor oil and may enter combustion chambers
Solution Approach 1:
The inner bore of the union nut is divided into two portions with different diameters, creating a shoulder that segments the flow path. This segmentation allows the system to handle both the high-pressure fuel connection and the diversion of leakage separately, preventing fuel from contaminating the motor oil while maintaining the threaded connection functionality.
Solution Approach 2:
The shoulder with indentation acts as an intermediary structure between the first and second portions of the inner bore. It provides a controlled path for leakage to escape through the indentation onto the exterior surface, serving as a mediator that prevents direct contamination of motor oil while maintaining the sealing function of the threaded connection.
2Object-affected harmful factors
If union nut is made long enough to protrude through cylinder head cap, then leakage is diverted outside, but device complexity increases
Solution Approach 1:
The union nut's inner bore is segmented into two portions with different diameters, creating a functional shoulder. This segmentation allows the leakage diversion function to be integrated into the nut's structure without requiring additional external components, thereby reducing overall device complexity while achieving effective leakage diversion.
Solution Approach 2:
The leakage diversion function is merged with the union nut structure itself through the graduated inner bore and shoulder design. Instead of requiring a separate diversion mechanism, the nut's own geometry provides the leakage escape path, combining multiple functions into a single component and simplifying the overall device.
3Object-affected harmful factors
If indentation is added to shoulder for leakage diversion, then leakage can escape, but manufacturing precision requirements increase
Solution Approach 1:
The indentation is created as a localized feature on the shoulder rather than requiring precision throughout the entire union nut. This local quality approach allows the majority of the nut to be manufactured with standard tolerances, while only the specific indentation area requires enhanced precision, thereby reducing overall manufacturing complexity while ensuring effective leakage diversion.
Data Source
AI summary
A threaded pipe coupling is disclosed which comprises a connection stub, a pipe, and a union nut, and in which any leakage quantities that occur can be carried away through the union nut.