Thermal resistor type air flow measuring apparatus

摘要

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.