GAS DETECTING DEVICE, AUTOMATIC FLAP CONTROL SYSTEM FOR AUTOMOBILE, AND GAS DETECTING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a gas detecting device capable of appropriately detecting a change in the concentration of gas components of a gas to be measured, an automatic flap control system, using the device, for automobile, and a gas detecting method.;SOLUTION: The gas detecting device 1 using a gas sensor element 2 wherein a sensor resistance value Rs is changed according to the change in the concentration of the gas components is provided with a sensor-resistance-value converting circuit 4 wherein a sensor output potential Vs falls in the case of a rise in the concentration of the gas components. Furthermore, the device 1 is provided with a decreasing peak hold circuit 5, wherein the output potential Vs is taken as a decreasing peak potential V5 when the output potential Vs is greater than the peak potential V5 and the peak potential V5 is gradually decreased with time when the output potential Vs is smaller than the peak potential V5, and a differential amplification circuit 7, a comparator 8, a switching circuit 9, which make a gas-component concentration rise signal Sg turned on when a differential between the peak potential V5 and the output potential Vs is greater than the first threshold voltage Vth1.;COPYRIGHT: (C)2001,JPO