Apparatus for measuring gas flow rate in a bypass passage and having a passage restriction portion downstream of the detecting element

摘要

An apparatus for measuring gas flow rate is comprised of a pipe body whose inside space performs as a passage for flowing measured gas. A housing including a generally U-shaped bypass passage is integrally formed with the pipe body. A plate-type flow-rate detection element is disposed in a first passage of the bypass passage, and a passage restricting portion is disposed in a second passage of the bypass passage downstream of the first passage. The inlet portion of the bypass passage is disposed in the vicinity of an axial center of the pipe body, and the outlet port of the bypass passage is disposed in the vicinity of a pipe wall of the pipe body. Therefore, the influence of a pulsating flow to the flow-rate detection element is decreased, and the high- accuracy detecting of gas flow-rate is executed.