Ngk Spark Plug Company, Limited

Tadashi Watanabe

Shunsuke Maeda

Masayoshi Matsui

Yoshihiro Nakamura

Yoshihiro Yamamoto

Akimitsu Sassa

Kenjiro Nishiyuki

Toshiki Hirokawa

Masahiro Kawakatsu

A glow plug including a substantially cylindrical housing extending in an axial direction; a rod-shaped heater unit having a front end protruding from the front end of the housing and movable in the axial direction; a connecting member connecting the heater unit to the housing within the housing and allowing the heater unit to move in the axial direction; and a pressure sensor that detects pressure received by the heater unit. The heater unit has a large-diameter portion at the rear end thereof and a small-diameter portion frontward of the large-diameter portion and having a diameter smaller than the diameter of the large-diameter portion. The connecting member connects the small-diameter portion of the heater unit to the housing within the housing.

Glow plug with combustion pressure sensor

A glow plug includes a cylindrical housing, a rod-shaped heater, a membrane portion, and a pressure sensor. The cylindrical housing extends along an axial direction. The rod-shaped heater extending along the axial direction is displaced along the axial direction and has one end portion disposed within the housing, and an other end portion which is exposed from the housing. The membrane portion connects together the heater and the housing and has a multi-layer construction which has a first layer and a second layer of which at least part is positioned nearer to the other end portion in the axial direction of the heater than the first layer. The pressure sensor measures a pressure within a combustion chamber in which the other end portion is disposed by making use of a displacement of the heater. A thickness of the second layer is larger than a thickness of the first layer.

Glow plug

A glow plug wherein a combustion gas prevention wall () extends radially outward on the outer circumferential surface of heater () such that when the heater () is viewed rearward from its forward end () along the axial direction, the combustion gas prevention wall () closes an annular gap Kat a position forward of annular membrane portion () of seal member (). The combustion gas prevention wall () has an outer diameter Dgreater than the inner diameter Dof forward end () of the housing.

A glow plug in which a convex portion () is formed in an outer peripheral surface () of a heater () in a part facing an inner peripheral surface () of a leading end part () of a housing () and interposed in a leading end side annular gap K, so as to maintain a gap with the inner peripheral surface (). A decline in detection accuracy can be prevented to the extent that combustion gas can be received by the leading end () of the convex portion () even if soot clogging should occur.

Growing community of inventors

Komaki, Japan

Tadashi Watanabe