Configuration of air intake parts applied to thermal type air flow measuring instrument

摘要

It is an object of the present invention to expand an air flow measuring range of a thermal type air flow measuring instrument. A squeeze 157 is provided upstream of a thermal type air flow measuring instrument 100 of a main air passage 155 to expand an air flow measuring range on the low flow rate side. Furthermore, a slit 158 is provided to introduce air from the outside of the main air passage 155 to a position downstream of the squeeze 157 where flow exfoliation occurs without passing through a main air passage inlet 156 to prevent a pressure drop from increasing at a high flow rate and expand the air flow measuring range on the high flow rate side.