Abstract: This apparatus measures and detects the air-flow taken into an intake pipe of an internal combustion engine, and includes an air-flow detecting sensor. The air-flow detecting sensor comprises a support frame made of heat-resistant insulation material, a heating line supported by the support frame on the upper side when viewed from the direction in which the air-flows, a heat-controlled heating current, and a resistance line also supported by the support frame on the lower side when viewed from the direction in which the air-flows which has a temperature characteristic. Air-flow detecting signals which represent the condition under which heat is transmitted to the resistance line through the air-flow are picked up from the sensor for every specified timing to set and calculate the transmitting coefficients of heat transmitted from the heating line to the resistance line, which is specified by the sensor and which is set corresponding to the amount of the signal detected by the sensor.

Abstract: A gas flow measuring apparatus is provided with an air flow sensor mounted in a suction duct upstream from a throttle valve and exposed to the air flow through the suction duct. The air flow sensor includes a ceramic flat plate mounted in the suction duct so that the main surfaces of the ceramic flat plate are parallel with the air flow. First and second temperature-dependent resistor coatings are formed on the main surfaces of the ceramic flat plate so that the first resistor coating and the second resistor coating are respectively formed on the downstream and upstream end portions of the ceramic flat plate by printing or evaporating a platinum. An electric heater coating is formed between the first and second resistor coatings but spaced therefrom to affect only the first resistor coating, and the heater coating is also formed by printing or evaporating a platinum.