Turbocharger Mating Ring Land Groove Ratio for Seal Lift-off
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Solution Overview
Problem
Typical turbochargers face issues with the carbon ring not 'lifting off' at optimal rotational speeds due to suboptimal geometry of grooved portions and land area to grooved area ratios, leading to inadequate sealing performance, excessive friction, and potential damage.
Innovation Solution
A mating ring with a land area to grooved area ratio between 1.3 and 2.9, featuring a land portion and a plurality of grooved portions, ensures the carbon ring lifts off at the optimal rotational speed, reducing mechanical losses and improving durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the grooved portions geometry and land area to grooved area ratio are not optimized, then the carbon ring may not lift off at the correct rotational speed, but optimizing these parameters is complex and requires precise geometric design
Solution Approach 1:
The patent applies parameter changes by optimizing the land area to grooved area ratio to a specific range (1.3 to 2.9) and adjusting the geometry parameters of the grooved portions (depth, width, spacing) to achieve optimal lift-off characteristics at specific rotational speeds. This resolves the contradiction by finding the optimal parameter values that ensure reliable sealing performance without requiring overly complex geometric designs.
2Reliability
If the carbon ring remains engaged with the mating ring at high rotational speeds, then sealing performance is maintained, but excessive friction occurs causing decreased turbocharger performance and potential damage
Solution Approach 1:
The patent applies dynamics by designing the grooved portions to enable the carbon ring to dynamically transition from an engaged state at low speeds to a lifted-off state at optimal rotational speeds. The grooved portions generate hydrodynamic pressure that lifts the carbon ring, reducing friction and energy losses while maintaining sealing performance through controlled dynamic behavior.
3Loss of energy
If the carbon ring lifts off at low rotational speeds, then mechanical losses are reduced, but sealing performance becomes insufficient
Solution Approach 1:
The patent applies parameter changes by carefully selecting the land area to grooved area ratio within the range of 1.3 to 2.9 and optimizing the grooved portions geometry to control the lift-off speed. This ensures the carbon ring maintains engagement at low speeds for adequate sealing while lifting off at the optimal rotational speed to reduce mechanical losses, resolving the contradiction between sealing performance and energy efficiency.
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 optimized ratio ensures the carbon ring disengages at the correct speed, reducing mechanical losses, improving turbocharger performance, and minimizing damage to both the carbon and mating rings.
Implementation Method 1
the carbon ring lifts off from the mating ring at the optimal rotational speed... reducing mechanical losses of the turbocharger
Data Source
AI summary
A turbocharger includes a shaft, a compressor wheel, and a seal assembly. The seal assembly includes a carbon ring having a carbon surface having a carbon ring inner diameter and a carbon ring outer diameter. The seal assembly also includes a mating ring having a mating surface facing the carbon surface of the carbon ring. The mating surface has a land portion configured to contact the carbon surface between a first mating diameter radially aligned with the carbon ring inner diameter and a second mating diameter radially aligned with the carbon ring outer diameter. The land portion has a land area between the first and second mating diameters. The mating surface defines a plurality of grooved portions. The plurality of grooved portions have a grooved area between the first and second mating diameters. A ratio of the land area to the grooved area is between 1.3 and 2.9.