AIR FLOWMETER FOR INTERNAL COMBUSTION ENGINE AND ITS MANUFACTURE

摘要

PURPOSE:To stabilize flow at a crossing part and to stabilize the output of a hot wire element by equalizing the diameter of the circular end part of a 2nd flow passage to that of the sectional circle of a 1st flow passage while aligning the center of the section of the circular end part with the center of the sectional circle of the 1st flow passage in the cross-section brought into contact with a groove bottom part. CONSTITUTION:An air suction flow passage branches into a main flow passage 3 and a subordinate flow passage 4 and 1st and 2nd flow passage 4A and 4B are formed. The flow passage 4A is sectioned circularly and has a hot wire element 6 and a temperature compensating element 7 internally. The flow passage 4B is formed of a groove formed in a bridge 9 and a plate 10 which covers it. Then the flow passage 4B has the circular end part 12 at the crossing part and this end part 12 has the circular center aligned with the center of the sectional circle of the flow passage 4A in the cross-section brought into contact with the groove bottom part 11 and is equal in radius. Therefore, no step is formed at the crossing part and dead volume is eliminated. Consequently, the flow at the crossing part becomes stable and the output of the hot wire element provided in the flow passage is stabilized.