| 摘要 |
<p>PURPOSE:To measure air flow rates with high accuracy irrespectively of the operating condition, by shortening the distance between the air inlet and air outlet of the by-pass path for executing the hot-wire type air flow rate measurement, and, at the same time, by extending the length of the by-pass path, so that influence of the back flow is prevented. CONSTITUTION:At a flow straightening section arising from a Venturi 2 of an air conduit 1, a partition wall 22 which forms an air inlet 4, an air outlet 10, and an air path 5, a resistance body 6 for hot-wire type air flow speed measurement, a resistance body for temperature compensation, and a flow speed measuring tube 3 provided with a straightening lattice, etc., are installed at right angle to the air flow. Because of this constitution, the distance between the inlet 4 and the outlet is shortened and the pressure difference between the inlet 4 and the outlet 10 becomes smaller. Moreover, the length of the path 5 is extended and the inertia of the straightened air flow becomes larger. Therefore, the air flow of internal combustion engines is highly accurately measured without having any influence from back flows, even when back flows are generated by the operating condition of engines. Moreover, when a ring- shaped air inlet 4 is installed to the wall of the path 1, the distance between the inlet 4 and the outlet 10 is substantially shortened and, at the same time, the air flow is excellently straightened and therefore, the same result can be obtained.</p> |
