Compressor Trim Adjuster for Chugging Noise Reduction
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Solution Overview
Problem
Internal combustion engines with compressors experience chattering noise during gear switching due to temporary operation near the surge limit, leading to inefficient compressor performance and vibration excitations.
Innovation Solution
Implementing a trim control system that adjusts the inlet cross-section of the compressor impeller to prevent backflow and minimize vibration excitations by moving the trim control into a covering position during gear switching, and returning to the release position when the risk of chattering is low.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the compressor operates at high mass flow and high pressure ratio during gear switching, then the compressor pressure ratio is maintained, but the compressor operates near the surge limit causing backflow and chattering noise
Solution Approach 1:
The control system detects the gear switching event in advance and proactively adjusts the trim adjuster to the covering position before the compressor reaches the surge limit. This preliminary action prevents the backflow bubble from forming by modifying the inflow cross-section ahead of time, thereby avoiding chattering noise while maintaining pressure ratio.
Solution Approach 2:
The trim adjuster is dynamically adjusted during gear switching operations. By changing the opening degree of the trim adjuster based on the detected gear switching state, the system adapts the compressor's inflow characteristics in real-time to prevent surge conditions while maintaining optimal pressure ratio performance.
2Object-affected harmful factors
If the trim adjuster is positioned in the covering position to prevent backflow, then chattering noise is reduced, but the inflow cross-section of the compressor impeller is reduced
Solution Approach 1:
The trim adjuster is dynamically positioned based on the gear switching state. During gear switching, it adopts the covering position to prevent backflow and reduce noise. Outside of gear switching operations, it returns to the release position to maximize inflow cross-section and maintain optimal compressor efficiency. This dynamic adjustment reconciles the conflicting requirements of noise reduction and flow area.
Solution Approach 2:
The trim adjuster is temporarily positioned in the covering position only during the periodic gear switching events rather than continuously. This periodic adjustment minimizes the impact on overall compressor performance while effectively suppressing chattering noise during the specific moments when surge conditions are likely to occur.
3Productivity
If the trim adjuster is positioned in the release position to maximize inflow cross-section, then compressor efficiency is improved, but the compressor is more susceptible to surge during gear switching
Solution Approach 1:
The system dynamically adjusts the trim adjuster position based on operating conditions. During normal operation, the trim adjuster remains in the release position to maximize inflow cross-section and maintain high compressor efficiency. During gear switching events, it transitions to the covering position to prevent surge. This dynamic behavior allows the system to optimize efficiency during steady-state operation while ensuring reliability during transient conditions.
Solution Approach 2:
The control system continuously monitors the gear switching state and provides feedback to adjust the trim adjuster position accordingly. When gear switching is detected, the feedback signal triggers the trim adjuster to move to the covering position, preventing surge conditions. This feedback mechanism ensures that the compressor maintains high efficiency during normal operation while being protected from surge during gear transitions.
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
This approach reduces chattering noise and maintains compressor efficiency by stabilizing the gas flow and preventing backflow into the fresh gas line, thereby improving the acoustic behavior and operational stability of the engine during switching processes.
Implementation Method 1
Due to the nozzle effect of the trim adjuster achieved in this way, the gas flow can be focused more strongly on the inlet cross-section of the compressor impeller near the hub with increasing control intervention (reduction of the inflow cross-section)
Implementation Method 2
The increase in the pressure of the fresh gas depends on the speed of the compressor impeller and the mass flow of the fresh gas passed over the compressor impeller
Data Source
Figure 1~2
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Figure 5~6
AI summary
A method for operating a motor vehicle with an internal combustion engine is provided, wherein the internal combustion engine comprises at least one combustion engine, which is connected to the driven wheels of the motor vehicle via a gearbox and optionally a clutch, and furthermore a fresh gas line, and wherein a compressor is integrated into the fresh gas line, to which a trim control is assigned, by which a peripheral section of the inlet cross-section of a compressor impeller of the compressor can be covered to a variable extent. In an open position of the trim control, the peripheral section of the inlet cross-section is covered relatively little, preferably as little as possible, and in a closed position of the trim control, it is covered relatively extensively, preferably as much as possible.According to the invention, the trim adjuster is moved to the cover position ST2 for the transition from a first operating state of the internal combustion engine, in which the transmission is in a first gear ratio position i1 and the trim adjuster is in the release position ST1, to a second operating state of the internal combustion engine, in which the transmission is in a second gear ratio position i2. This prevents or minimizes the noise generation known as chugging.