Test Bench Characterization for Consistent Sound Level Measurement

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Solution Overview

Problem

Test benches used for evaluating sound levels in motor vehicle components often produce inconsistent results due to technical variances, leading to components being classified differently based on the same measurements, causing issues in determining whether a component is sufficiently quiet or excessively loud.

Innovation Solution

A method is developed to characterize test benches by calculating a general limiting value based on sound level measurements, using a distribution function normalization and standard deviation, allowing for comparable assessments across different test benches.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple test benches are used to test components simultaneously, then productivity is improved, but measurement precision deteriorates due to technical variances between test benches

Engineering Contradiction:

Improvetesting capacityVSAvoidsound level measurement consistency

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent applies parameter changes by introducing a correction factor that adjusts the measured sound levels based on the specific test bench characteristics. Each test bench is characterized by parameters such as mean value and standard deviation of sound level measurements, and correction factors are calculated to compensate for variances between test benches, thereby enabling consistent comparisons across multiple test benches while maintaining high productivity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses an intermediary approach by introducing a correction factor as a mediator between the raw measurement and the final assessment. This correction factor, derived from the test bench's statistical characteristics (mean and standard deviation of sound level measurements), serves as a bridge that harmonizes measurements from different test benches, allowing simultaneous testing across multiple benches while ensuring measurement precision

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If the same limiting value is used for all test benches, then ease of operation is improved, but measurement precision deteriorates due to test bench variances

Engineering Contradiction:

Improvelimiting value applicationVSAvoidsound level classification accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent modifies the limiting value parameter by introducing test bench-specific correction factors. Instead of using a single universal limiting value, the patent calculates adjusted limiting values for each test bench based on its statistical characteristics (mean and standard deviation of sound level measurements). This allows the ease of operation to be maintained through systematic application while achieving measurement precision through personalized limiting values for each test bench

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS20240176849A1Method for Characterizing a Test Bench and Associated Method for Testing and Producing a Component

Publication Date: 2024.05.30 BAYERISCHE MOTOREN WERKE AG

AI summary

A method for characterizing a test bench designed for measuring sound levels of components includes determining measured values which characterize respective sound levels emitted by the components at a same operating point and which are measured by the test bench, calculating a distribution function from the measured values, normalizing the distribution function, calculating a mean value of the normalized distribution function, and calculating a standard deviation of the normalized distribution function.