The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 18, 2009
Filed:
Jul. 07, 2006
Takeo Sasanuma, Aichi, JP;
Yoshikuni Sato, Nagoya, JP;
Shunsuke Tamura, Komaki, JP;
Shinji Kumazawa, Nagoya, JP;
Hisashi Sasaki, Konan, JP;
Takeo Sasanuma, Aichi, JP;
Yoshikuni Sato, Nagoya, JP;
Shunsuke Tamura, Komaki, JP;
Shinji Kumazawa, Nagoya, JP;
Hisashi Sasaki, Konan, JP;
NGK Spark Plug Co., Ltd., Aichi, JP;
Abstract
A liquid state detection sensor in which temperature information of a urea aqueous solution is obtained on the basis of a voltage value acquired after the start of energization of a heating resistor corresponding to a resistance value of the heating resistor (S-S). Damage to the heating resistor is prevented by suspending the energization if the thus-obtained temperature is lower than or equal to the freezing point (S: yes and S). If the temperature is higher than the freezing point (S: no), a voltage value corresponding to a resistance of the heating resistor after a lapse of 700 ms (Sand S) and a urea concentration of the urea aqueous solution are determined from a difference ΔV from the previously acquired voltage value. A more accurate urea concentration can be detected by making a correction using the previously obtained temperature information of the urea aqueous solution (S-S).