Patent ID: 6220090
Filing Date: 2001-04-24
Classification: G01F

Abstract:
An air flow meter assembly comprising:a main air flow passage;a bypass member disposed in said main air flow passage, said bypass member defining a bypass passage for bypassing a portion of air flowing through said main air flow passage; anda sensor unit disposed in said bypass passage for detecting an air flow amount in said bypass passage, wherein said bypass passage includes:an inflow port;an upstream passage in flow communication in said inflow port and the sensor unit is disposed in said upstream passage;a downstream passage in flow communication with said upstream passage and disposed downstream thereof with respect to a direction of air flow in said bypass passage, said downstream passage being defined by a partition wall on an upstream side thereof with respect to an air flow direction in said main air flow passage, a downstream wall on a downstream side thereof with respect to said main passage air flow direction, and opposing side walls facing each other in a direction perpendicular to said main passage air flow direction; andan outflow port in flow communication with said downstream passage and disposed at a downstream side thereof with respect to said bypass passage air flow direction, said outflow port being defined on three sides by said partition wall and said opposing side walls, said downstream wall extending in a direction of air flow in said downstream passage a distance less than a distance that each of said partition wall and said opposing side walls extend in said downstream passage air flow direction, wherein said outflow port is open in said downstream passage air flow direction and open in said main passage air flow direction so that air flows in the outflow port both in parallel with and perpendicular to the main passage air flow direction and in parallel with and perpendicular to the downstream passage air flow direction, wherein the bypass portion of the air that is flowing in the bypass passage gradually merges with the air flowing in the main air flow passage.