Airflow Measurement Pulsation Amplitude Correction

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Solution Overview

Problem

Existing measurement control devices face accuracy issues in correcting airflow due to backward flow outside the measurement device, leading to increased pulsation error and decreased correction accuracy.

Innovation Solution

A measurement control device that calculates pulsation amplitude by considering the difference between pulsation maximum and minimum values, rather than using average airflow as a denominator, and acquires correction parameters using a correction characteristic to enhance accuracy even during backward flow occurrences.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If correction parameter is acquired based on pulsation amplitude calculated using average airflow as denominator, then calculation is simplified, but measurement precision deteriorates during backward flow conditions

Engineering Contradiction:

Improvecalculation complexityVSAvoidairflow correction accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent changes the calculation parameter from using average airflow as denominator to using the difference between pulsation maximum and minimum values. This parameter change ensures that the pulsation amplitude calculation remains accurate even when backward flow occurs, thereby maintaining measurement precision without significantly increasing calculation complexity.

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If conventional pulsation amplitude calculation method is used, then calculation process is simple, but correction accuracy decreases during backward flow

Engineering Contradiction:

Improvecalculation process simplicityVSAvoidcorrection accuracy

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The invention modifies the calculation parameter from average airflow to the difference between pulsation maximum and minimum values. This change maintains calculation simplicity while significantly improving reliability during backward flow conditions, as the new parameter is not affected by the direction of airflow.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If average airflow is used as denominator for pulsation amplitude, then calculation is straightforward, but measurement precision worsens when backward flow occurs outside measurement device

Engineering Contradiction:

Improvecalculation methodVSAvoidpulsation amplitude accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent implements a parameter change from using average airflow as denominator to using the difference between pulsation maximum and minimum values. This change eliminates the sensitivity to backward flow conditions while keeping the calculation method straightforward and not significantly increasing device complexity.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS11365996B2Measurement control device and flow measurement device

Publication Date: 2022.06.21 DENSO CORP

AI summary

In a measurement control device that measures an airflow, an amplitude calculator calculates, by use of an output value of a sensor, a pulsation amplitude that is a difference between a pulsation maximum and an average airflow or a difference between the pulsation maximum and a pulsation minimum. The pulsation maximum is a maximum value of pulsation generated in the airflow, the average airflow is an average value of the pulsation, and the pulsation minimum is a minimum value of the pulsation. A correction parameter acquirer acquires a correction parameter corresponding to the calculated pulsation amplitude by use of a correction characteristic. An airflow corrector corrects the airflow by use of the acquired correction parameter.