| 摘要 |
<p>PURPOSE: To provide an engine intake air flow measuring device simplified in structure in which the air flow rate of a pulsating flow including counterflow can be precisely measured with one air temperature probe. CONSTITUTION: A switching means formed of a multiplexer 11, a timer 12, and a buffer amplifier 16 switch-controls one flow measuring circuit formed of a hot wire probe 1, an air temperature probe 3, resistors 5, 4, a differential amplifier 7, and a transistor 9 and the other circuit formed of a hot wire probe 2, the air temperature probe 3, resistors 5, 6, a differential amplifier 8, and a transistor 10. Further, flow rate signals A, B which show voltages in points A, B are switched by a NOT element 13 or transistors 14, 15, inputted to respective sample holds 19, 20 having adding circuits 1 and analog switches 17, 18, and passed through respective smoothing circuits 22 to output a normal flow rate signal and a direction signal of flow judged by a comparator 23.</p> |
