Variable Nozzle Turbocharger Soot Scraping Mechanism
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Solution Overview
Problem
Foreign substances like soot accumulate between the unison ring and the main plate in variable nozzle turbochargers, disrupting the operation of the variable nozzles due to their exposure to exhaust gas.
Innovation Solution
A configuration with a gap between the facing surfaces of the unison ring and the main plate, featuring projections and recessed portions that alternately arranged along the circumferential direction, allowing foreign substances to be scraped out during the circumferential displacement of the unison ring, preventing accumulation and maintaining nozzle operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the unison ring and main plate are exposed to exhaust gas to enable variable nozzle operation, then the nozzle can adjust flow speed, but foreign substances like soot accumulate between the unison ring and main plate, disturbing circumferential displacement
Solution Approach 1:
The patent extracts the harmful function of soot accumulation by introducing projections that actively remove soot from the gap between the unison ring and main plate during circumferential displacement. The projections scrape out accumulated foreign substances, preventing them from interfering with the circumferential motion while maintaining the exposed configuration needed for flow control.
Solution Approach 2:
The variable nozzle mechanism serves itself by using its own circumferential displacement motion to scrape out accumulated soot through the projections. The normal operational movement of the unison ring automatically performs the cleaning function, eliminating the need for separate maintenance operations and ensuring continuous reliable operation.
2Speed
If the unison ring is rotated to change nozzle opening degrees, then flow speed is adjusted, but accumulated foreign substances disturb the circumferential displacement of the unison ring
Solution Approach 1:
The projections extend into the gap between the unison ring and main plate to actively scrape out and remove accumulated soot. This extraction of foreign substances prevents them from interfering with the smooth circumferential displacement of the unison ring, ensuring easy operation while maintaining flow speed control capability.
3Reliability
If the gap between unison ring and main plate is reduced to prevent soot accumulation, then foreign substance accumulation is minimized, but the mechanism for scraping out soot through projections cannot function
Solution Approach 1:
The patent segments the facing surfaces of the unison ring and main plate by introducing multiple projections and corresponding recesses. This segmentation creates channels and scraping surfaces that actively remove soot during circumferential displacement, preventing accumulation without requiring an excessively large gap. The segmented structure balances gap size with soot removal capability.
Data Source
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AI summary
In a variable nozzle turbocharger, variable nozzles operate through circumferential displacement of a unison ring (12) aligned with a main plate (10) in a thickness direction thereof. A gap is formed between facing surfaces (F1, F2) of the unison ring and the main plate, and projections (41) that project from one surface (F1) out of the facing surfaces (F1, F2) toward the other surface (F2) are provided in the gap. When the unison ring is displaced in its circumferential direction, foreign substances attached to the gap between the facing surfaces (F1, F2) are scraped out from the gap by the projections.