Anti-Dirt Property of Hot-Wire Air Flow Meter

Hitachi has recently developed a hot-wire air flow meter which uses a temperature-sensitive resistor of an extremely thin platinum wire wound around a ceramic bobbin and coated with glass. This temperature-sensitive resistor, or a hot wire, is located in a bypass of the intake air passage of an engine and responds exactly for the effective control of engine operation. The flow meter of this construction is sturdy enough to withstand impacts of backfires and vibration and reduces variation in engine output characteristic likely to be caused by dust and dirt present in the intake air. Furthermore, this device requires no cleaning or other maintenance.