Letting flow exoergic resistor type mass air flow

摘要

PROBLEM TO BE SOLVED: To secure measuring precision for a heating resistor type air flow measuring instrument, to reduce a characteristic variation caused by deposition of dust, in particular, to restrain the characteristic variation to the minimum even in case of a nano-particle size of soot (carbon).;SOLUTION: The measuring precision for a flowmeter and the reduction of the dust deposition are compatible by differing an air striking angle to a heating resistor from a colliding angle of dust. For example, the heating resistor is arranged inclinedly in a downstream of a curved apex of a curved passage, the dust flies in along a direction separated toward an outside of a curve by centrifugal force, even in the light-weight of soot in a midway of the curved passage, and an air-flowing angle is differed from a collision angle with the dust flying in to collide with a heat radiation face of the heating resistor. The dust is thereby difficult to be deposited because of an air flow, by making steep a collision angle of the dust onto the heat radiation face of the heating resistor while keeping the measuring precision of the flowmeter.;COPYRIGHT: (C)2007,JPO&INPIT