a hot - wire air flow meter for detecting air flow intake has a main passage and a generally parallel sub - passage for bypassing said main passage , and located in the sub - passage is a hot - wire element for detecting air flow intake . a dished member is located upstream from an inlet of the sub - passage , the dished member having a base portion adjacent the sub - passage inlet and an upstream projecting edge extending from said base portion . the upstream extending edge at least partially surrounds the inlet and is located between the sub - passage inlet and the main passage , the effect of the dished member tending to stabilize air flow entering the sub - passage so that the air flow is less affected by bends in pipework upstream from the air flow meter .