Thermal resistor type air flow measuring apparatus
AssigneesHitachi, Ltd., Hitachi Car Engineering Co., Ltd.
InventorsChihiro Kobayashi, Shinya Igarashi, Masayuki Kozawa, Atsushi Kanke
Life of this patent
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Abstract
To correct properly the error of the thermal resistor type air flow measuring apparatus caused by the pulsation in the intake pipe in detecting the air flow of the internal combustion engine, a thermal resistor is placed in a passage inside the auxiliary air passage into which the reverse flow hardly flows directly and the error caused by the reverse flow is prevented. The existence of the reverse flow is judged by the ratio of the amplitude to the mean value using the maximum value, the minimum value and the mean value of the forward air flow waveform, and the error caused by the increase of the forward air flow is corrected.
Claims21
A thermal resistor type air flow measuring apparatus, comprising
- an auxiliary air passage arrangeable in an intake air passage of an internal combustion engine and having at least one bend;
- a thermal resistor arrangeable in said auxiliary air passage;
- and
- a judging means for judging the existence of a reverse flow in said intake air passage based on a maximum value and a minimum value of an air flow signal value obtained by said thermal resistor.
A thermal resistor type air flow measuring apparatus, comprising
- an auxiliary air passage arrangeable in an intake air passage of an internal combustion engine and having at least one bend;
- a thermal resistor placed in said auxiliary air passage;
- and
- a correcting means for correcting a measurement error due to a reverse flow generated in said intake air passage based on a maximum value and a minimum value of an air flow signal value obtained by said thermal resistor.
A control apparatus for an internal combustion engines, comprising
- a judging means for judging the existence of a reverse flow in an air passage to be measured in a thermal resistor type air flow measuring apparatus based on a maximum value and a minimum value of an air flow signal value supplied from said thermal resistor type air flow measuring apparatus.
A control apparatus for an internal combustion engine, comprising
- a correcting means for correcting a measurement error due to a reverse flow in a air passage to be measured in a thermal resistor type air flow measuring apparatus based on a maximum value and a minimum value of an air flow signal value supplied from said thermal resistor type air flow measuring apparatus.
A reverse flow judging method of a thermal resistor type air flow measuring apparatus having
- an auxiliary air passage in an intake air passage of an internal combustion engine and having at least one bend;
- and
- a thermal resistor in said auxiliary air passage, comprising the steps of
- detecting a maximum value and a minimum value of an air flow signal value from said thermal resistor;
- and
- judging the existence of a reverse flow in said intake air passage based on said detected maximum value and said detected minimum value.
An error correcting method of a thermal resistor type air flow measuring apparatus having
- an auxiliary air passage in an intake air passage of an internal combustion engine and having at least one bend;
- and
- a thermal resistor in said auxiliary air passage, comprising the steps of
- detecting a maximum value and a minimum value of an air flow signal value from said thermal resistor;
- and
- determining a measurement error due to a reverse flow of a fluid to be measured by the thermal resistor type air flow measuring apparatus based on said detected maximum value and said detected minimum value.
Dependencies are inferred from the claim text.