THERMAL TYPE FLOW RATE MEASURING APPARATUS

PURPOSE:To integrate the apparatus compact as a whole, by arranging a bypass air intake port on a suction pipe wall on the side where a throttle valve is opened downstream side where the valve is opened downstream with one lengthwise end thereof tilted CONSTITUTION:In the inflow of a bypass air sucked into an engine detouring a throttle valve 2, an intake port 41 for the bypass air is provided as formed in proximity to the valve 2 and a rectangular flat thermal type flow sensor 1 as formed slightly on the upstream side from the intake port 41. The intake port 41 is formed on a suction pipe wall on the side where the value 2 is opened downstream while a flow sensor 1 is so arranged that a plate surface thereof is positioned almost on the center line of a suction path 3 and on a plane almost vertical to the direction of supporting the shift of the valve 2. Moreover, one lengthwise end of the sensor 1 is set to the downstream on the side where the valve 2 is opened downstream. For example, this enables the setting of the sensor 1 within 35mm-75mm on the upstream of the valve 2 in a 50mm dia. suction pipe, thereby permitting compactization of the apparatus.