Method for determining a mass airflow
AssigneeSiemens Aktiengesellschaft
InventorsWerner Frie, Christoph Haberer, Harald Liederer
Life of this patent
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Abstract
In a method for determining a mass airflow in an air duct using a mass airflow sensor, sensor signals at successive times, indicating the magnitude of the mass airflow, are captured and, using a characteristic curve for the mass airflow sensor, corresponding values are determined for the mass airflow. In doing so, a time series of signals is subjected to a vibration analysis, which determines a fundamental vibration and at least one prescribed harmonic vibration of the fundamental vibration, and the existence of a backflow is established if the ratio of the strength of the harmonic vibration to the strength of the fundamental vibration exceeds a prescribed threshold value.
Claims15
A method for determining a mass airflow in an air duct, comprising:
- providing a mass airflow sensor to capture signals, each of which corresponds to an amount of a value of the mass airflow, such that sensor signals are captured and values are determined for the mass airflow using a characteristic curve;
- subjecting a time series of signals, which comprises several signals which have been captured, to a vibration analysis, which determines a fundamental vibration and at least one prescribed harmonic vibration of the fundamental vibration and compares parameters of the fundamental vibration and the prescribed harmonic vibration;
- and
- establishing a backflow against the average mass airflow, due to pulsations, when the ratio of the parameters of the harmonic vibration to the fundamental vibration exceeds a prescribed threshold value.
A mass airflow sensor unit, comprising:
- a mass airflow sensor, with which a signal is formed corresponding to a magnitude for a mass airflow in an air duct;
- and
- an analysis device, linked to the mass airflow sensor, converts the signals from the mass airflow sensor into values for the mass airflow.
Dependencies are inferred from the claim text.