Air flow measuring device
AssigneeDenso Corporation
InventorsTeruaki KAIFU, Noboru KITAHARA, Kengo ITO
Life of this patent
Estimating the term…
Abstract
An air flow rate measuring device measures an air flow rate based on an output value of a sensing unit placed in an environment that allows air to flow therethrough. The air flow rate measuring device includes: an acquisition unit configured to acquire the output value; a storage unit configured to store uneven flow information that indicates an uneven flow state of the air in the environment; a pulsation error correction unit configured to correct the air flow rate by using at least one of the uneven flow information and the output value such that the pulsation error Err in the air flow rate caused by the uneven flow becomes smaller.
Claims8
An air flow measuring device configured to measure an air flow based on an output value of a sensing unit installed in an environment that allows air to flow therethrough, the air flow measuring device comprising:
- an acquisition unit configured to acquire the output value;
- a storage unit configured to store uneven flow information that indicates an uneven flow state of air in the environment;
- a pulsation error correction unit configured to correct an air flow rate by using at least one item of the uneven flow information and the output value so that a pulsation error of the air flow rate caused by the uneven flow becomes smaller;
- and
- a state acquisition unit configured to acquire pulsation state information that indicates a state of pulsation in the air flow rate, wherein
- the state acquisition unit is configured
- to calculate an average flow rate, which is an average value of the air flow rate in a predetermined period, from the output value
- to determine a pulsation maximum value, which is a maximum value of the air flow rate
- to calculate a difference between the pulsation maximum value and the average flow rate to calculate a pulsation amplitude of the air flow rate
- to divide the pulsation amplitude by the average flow rate to calculate a pulsation rate of the pulsation waveform of the air in the output value and
- to acquire the pulsation rate as the pulsation state information, and
- the pulsation error correction unit is configured to correct the air flow rate by using the pulsation state information in addition to the uneven flow information and the output value so that the pulsation error of the air flow rate caused by the uneven flow becomes smaller.
An air flow measuring device comprising:
- a storage device configured to store uneven flow information that indicates an uneven flow state of air in an environment in which a sensing unit is installed;
- and
- a processor coupled to the storage device and configured to perform following steps:
- to acquire an output value of the sensing unit;
- to measure an air flow based on the output value;
- to calculate an average flow rate, which is an average value of the air flow rate in a predetermined period, from the output value;
- to determine a pulsation maximum value, which is a maximum value of the air flow rate;
- to calculate a difference between the pulsation maximum value and the average flow rate to calculate a pulsation amplitude of the air flow rate;
- to divide the pulsation amplitude by the average flow rate to calculate a pulsation rate of the pulsation waveform of the air in the output value;
- and
- to correct the air flow rate by using the uneven flow information, the output value, and the a pulsation rate to reduce a pulsation error of the air flow rate caused by the uneven flow.
Dependencies are inferred from the claim text.