Ngk Spark Plug Company, Limited

Fujitsu Corporation

Takashi Nakashima

Yuichi Yamada

Makoto Tanaka

Takaya Yoshikawa

Hiroaki Yamazaki

Satoshi Ishikawa

Masashi Ando

Takafumi Shichida

Atsushi Niwa

Shoji Fuwa

Fumiyasu Tanaka

A protector () of a gas sensor () includes an inner protector () and an outer protector (). The inner protector accommodates a gas sensor element () and has a tubular side wall () having inner gas introduction holes (), and a bottom wall (). The outer protector has a tubular side wall () having outer gas introduction holes (), a frustum-like taper wall () tapering frontward and an outer gas discharge hole () formed inside a front end edge () of the taper wall. When SL represents an area defined by the front end edge of the taper wall, the area S of the opening of the outer gas discharge hole satisfies the relational expression &#xbd;&#xd7;SL&#x2266;S&#x2266;SL. A cover portion () and a bottom wall () are partially away from each other along the axial direction, thereby forming side openings ().

Gas sensor

A gas sensor () including a protector () for protecting a detection portion () of a sensor element (). The protector () has an inner protector () and an outer protector (). A diameter r of an exhaust hole () formed in the inner protector () and an axial distance h between a front endof the sensor elementand the exhaust hole () satisfy a relation r&#x2266;2h/15+&#x2153;.

In a protector () for protecting a detecting portion () of a sensor element () of a gas sensor (), the opening area of individual inner introduction holes () and () formed in an inner protector () is 3.5 mmor less. In this manner, the amount and size of water droplets able to pass through the inner introduction holes () and () and to adhere to the sensor element () is restricted. In order to ensure good gas replaceability between the interior and the exterior of the inner protector () so as to attain quick gas response, the total opening area of the inner introduction holes () and () is 10 mmor more.

A gas sensor is constructed as follows. A protector () covering around a gas sensing element () has an inner hollow-cylindrical portion () and an outer hollow-cylindrical portion () that is provided coaxially with the inner hollow-cylindrical portion () with an air space () in between. Outer-wall gas inlet openings () are formed in the outer hollow-cylindrical portion (), and guiding bodies () extending inward are attached to the outer-wall gas inlet openings (). Inner-wall gas inlet openings () are formed in the inner hollow-cylindrical portion () at positions nearer to the gas sensing element () than the outer-wall gas inlet openings (). A side wall () face of the inner hollow-cylindrical portion () opposite the outer-wall gas inlet openings () is formed so as to be parallel to a side wall () of the outer-hollow cylindrical portion () or so as to have a slop-like shape with a diameter enlarging in the axial direction toward a bottom wall () of the protector (). A discharge opening () for a gas to be measured is formed in the bottom wall ().

A signaling virtual channel (SVC) is established only when it is necessary so that a bandwidth reserved for a signaling channel for transmitting signaling information is usable for transmitting communication information. The SVC is established between a subscriber terminal and an asynchronous transfer mode (ATM) exchange system by selecting the virtual path identifier (VPI) and the virtual channel identifier (VCI) for signaling only when a request for a call connection is made by the subscriber terminal or only when a notification of reception of a call is sent to the subscriber terminal. A communication path between the subscriber terminal and the ATM exchange system is established for transmitting communication information by transmitting communication call setting information through the SVC. The SVC is released after an establishing operation of the communication path is completed.

Growing community of inventors

Aichi, Japan

Takashi Nakashima