Title:
GAS DETECTOR AND AUTOMOBILE VENTILATION SYSTEM
Document Type and Number:
WIPO Patent Application WO/2001/092864
Kind Code:
A1
Abstract:
The invention provides a gas detector for detecting the change in concentration of specific gas while reducing environmental effects, such as temperature, humidity and wind velocity, and also provides an automobile ventilation system. A gas detector (10) and an automobile ventilation system (100) use a gas sensor element (11) whose sensor resistance Rs varies with the concentration of gas such as NOx. A sensor output value S(n) is obtained by A/D conversion of the output from a sensor resistance converter circuit (14). A base value B(n) is determined from B(n)=B(n-1)+k1{S(n)-B(n-1)}, and a difference D(n)=S(n)-B(n) is also determined. If a rise in concentration of gas makes the difference exceed a predetermined concentration threshold, a signal indicative of excessive concentration is generated to close a flap (34), and a base value B(n) is determined from B(n)=B(n-1)+k2{S(n)-B(n-1)} using a coefficient k2 smaller than k1.
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Inventors:
KIMOTO YUJI (JP)
MATSUOKA TOSHIYA (JP)
MATSUOKA TOSHIYA (JP)
Application Number:
PCT/JP2001/004457
Publication Date:
December 06, 2001
Filing Date:
May 28, 2001
Export Citation:
Assignee:
NGK SPARK PLUG CO (JP)
KIMOTO YUJI (JP)
MATSUOKA TOSHIYA (JP)
KIMOTO YUJI (JP)
MATSUOKA TOSHIYA (JP)
International Classes:
B60H3/00; G01N33/00; (IPC1-7): G01N27/12
Foreign References:
| JPH11259779A | 1999-09-24 | |||
| JPH0871357A | 1996-03-19 |
Other References:
See also references of EP 1286155A4
Attorney, Agent or Firm:
Oguri, Shohei (28th floor ARK Mori Building 12-32 Akasaka
1-chome Minato-ku, Tokyo, JP)
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