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Heating resistor type air flow rate measuring device and method of correcting measurement error

A technology of air flow and measuring device, which is applied in the direction of measuring device, volume flow ratio measurement, electrical control, etc., can solve the problems of insufficient air flow correction, change of measurement error, inconsistent relationship between opening and inspiratory pulsation rate, etc.

Inactive Publication Date: 2006-09-06
HITACHI LTD
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  • Description
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Problems solved by technology

[0010] Moreover, in the running state of the engine, if the air pressure and temperature change, the resonance frequency of the pulsation changes, the relationship between the engine speed, the accelerator opening degree and the intake pulsation rate is inconsistent, and the measurement error changes.
resulting in insufficient air flow correction

Method used

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  • Heating resistor type air flow rate measuring device and method of correcting measurement error
  • Heating resistor type air flow rate measuring device and method of correcting measurement error
  • Heating resistor type air flow rate measuring device and method of correcting measurement error

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Embodiment Construction

[0038] Preferred embodiments of the present invention will be described based on Examples shown in the drawings.

[0039] Embodiments of the present invention will be described in detail with reference to the following drawings.

[0040] FIG. 1 is a schematic diagram of a heating resistor type air flow measuring device according to an embodiment of the present invention. As an example, a device for measuring the flow rate of air flowing in an intake pipe of an automobile is shown.

[0041] First, the operating principle of the heating resistor type air flow measuring device will be described.

[0042] The sensor circuit (drive circuit) 100 of the heating resistor type air flow measuring device is basically composed of a bridge circuit and a feedback circuit.

[0043]The bridge circuit has a heating resistor 101 for measuring the intake air flow, a resistor 102 for compensating the intake air temperature, and fixed resistors 103, 104. The heating resistor 101 and the temperat...

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Abstract

This invention relates to a measurement error attributable to intake air pulsation of a heating resistor type air flow rate measuring device is corrected. A measurement error correction method not dependent on an intake system of a vehicle is provided. An output from a sensing circuit (100) is sampled at prescribed time intervals. Output values thus sampled are successively converted to flow rate values. A first flow rate value is determined by averaging the flow rate values thus obtained in a prescribed amount of time. Separately, the output from the sensing circuit (100) is averaged for a prescribed amount of time. The average output value thus obtained is converted to a second flow rate value. A correction value for correcting a measurement error is determined based on a difference between the first and second flow rate values.

Description

technical field [0001] The present invention relates to a device for measuring air flow rate using a heating resistor, for example, a heating resistor type air flow measuring device suitable for measuring the flow rate of air sucked into an automobile internal combustion engine. In particular, it relates to correction of measurement errors caused by inspiratory pulsations. Background technique [0002] As an air flow measurement technique for an internal combustion engine, a heating resistor type air flow measurement device is known. It utilizes the relationship that the heat absorbed by the heating resistor increases monotonically with respect to the air flow rate, and since it can directly measure the mass flow rate, it is widely used as a flow meter for automobile fuel control. [0003] In the heating resistor type air flow measuring device, the relationship between the output voltage of the sensor circuit (measurement circuit) and the air flow is a nonlinear output. In...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01F1/68G01F1/696G01F1/69F02D41/18
CPCG01F5/00G01F1/69G01F1/698G01F1/72G01F1/6965
Inventor 小林千寻
Owner HITACHI LTD
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