Ngk Spark Plug Company, Limited

Toshiyuki Matsuoka

Takio Kojima

Yuzo Higuchi

Yoshinori Tsujimura

Shunsuke Maeda

Masanori Suda

Shinsuke Itoh

Takashi Mori

Takuya Mizuno

Yuichiro Hanawa

A glow plug including a pressure sensor () and a heater (). The glow plug includes a position-defining member which defines the positional relationship between the pressure sensor () and the heater () and has a coefficient of thermal expansion greater than that of the heater. The pressure sensor () is fixed at a predetermined sensor reference position relative to the position-defining member. The heater () is held by a heater-holding member () in such manner that an attachment position A of the heater-holding member to the heater can be displaced, with a change in external pressure, relative to a predetermined heater reference position defined by the position-defining member. A displacement transmission member () is arranged between the heater () and the pressure sensor () so as to transmit displacement of the heater () to the pressure sensor (). The coefficient of thermal expansion of the displacement transmission member () is rendered greater than that of the position-defining member.

Glow plug

A pressure detection apparatus has a pressure-sensitive resistor whose first resistance varies according to pressure and a change of its own temperature, a temperature-sensitive resistor which has a same resistance-temperature coefficient as the pressure-sensitive resistor and whose second resistance varies according to the change of the temperature, a current source supplying first and second constant-currents to the pressure-sensitive and temperature-sensitive resistors respectively, and a pressure signal generation output section. The current source adjusts the first and second constant-currents so that when the pressure is an initial pressure, a reference first voltage appearing across the pressure-sensitive resistor and a reference second voltage appearing across the temperature-sensitive resistor become equal to each other. The pressure signal generation output section outputs a first voltage signal corresponding to the pressure on the basis of a difference voltage between a first voltage of the pressure-sensitive resistor and a second voltage of the temperature-sensitive resistor.

Pressure detection apparatus

A pressure sensor has a Si device having a first main surface that has a bonded area, a second main surface parallel to the first main surface, a pressure-sensitive resistor formed on the first main surface, and a joining assist pattern formed on the first main surface, and a pressing member bonded to the bonded area on the first main surface and compressing the Si device in a thickness direction. The pressure-sensitive resistor has a first bonded section which is placed within the bonded area of the first main surface and is bonded to the pressing member. The joining assist pattern has a second bonded section which is made of the same material as the first bonded section of the pressure-sensitive resistor and is placed within the bonded area of the first main surface and is bonded to the pressing member.

Pressure sensor

Growing community of inventors

Nagoya, Japan

Toshiyuki Matsuoka