| 摘要 |
PROBLEM TO BE SOLVED: To provide a gas-detecting apparatus that uses a simple processing, can reliably and readily detect increase in gas concentration, and causes less erroneous judgments, and to provide an auto ventilation system for vehicles using the apparatus. SOLUTION: A gas-detecting apparatus 10 using a gas sensor element 11 and an auto ventilation system 100 for vehicles acquire a sensor output value S(n), calculate a base value B(n) by an expression (1): B(n)=B(n-1)+ k1[S(n)-B(n-1)]-k2[S(n)-S(n-5)] and an expression (3): B(n)=S(n) in the case of S(n)≥B(n-1) and S(n)<B(n-1), respectively, and further calculate a differential value D(n)=S(n)-B(n). When the differential value becomes larger than a concentration high threshold value, a concentration high signal is generated, a flap 34 is closed, and then the base value B(n) is calculated by an expression (4): B(n)=B(n-1)+k3[S(n)-B(n-1)]-k4[S(n)-S(n-5)]. When the differential value becomes smaller than a specific concentration low threshold, a concentration low signal is generated and the flap 34 is opened. COPYRIGHT: (C)2003,JPO
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