Hot wire type of air flow meter and internal combustion engine using the same

Claim 1

A hot wire type air flow meter including a main flow passage forming an air intake flow passage of an internal combustion engine, a hot wire element for measuring intake air, and a bypass having said hot wire element therein and disposed fully in said main flow passage, and said bypass consisting of a first passage formed in the axial direction of said main flow passage and a second presage formed in the radial direction of said main flow passage, the radially facing outlet rim of the bypass outlet port at the end of the radial passage having a wind shield wall (204; 224; 234) radially extending from the upper stream side of said outlet rim into said main flow and a further wind shield wall (206; 236) radially extending from the downstream side of said bypass outlet rim into said main stream, characterised in that the width of said wind shield wall (236) provided at the downstream side of said bypass outlet port (232d) is smaller than the width of said upstream wind shield wall (234) said widths being measured perpendicularly to said axial and radial directions.