| 摘要 |
Provided is a glow plug such that the development of a long-term disconnection due to a decrease in resistance value caused by a decrease in the Al concentration in a heating coil can be prevented, and a short-term disconnection of the heating coil due to an excessive increase in temperature at the time of a rapid increase in temperature can be prevented, whereby an increase in burn-out life can be achieved. The glow plug includes a coil housed in a tube. The coil includes a heating coil of an Ni-Cr alloy disposed on a front end side in the heating coil, and a control coil connected to a rear end side of the heating coil. The coil has a normal temperature resistance value of 300 m© to 500 m©. The accumulated amount of heat generated by the heating coil for two seconds from the start of energization is 400 W or less. The ratio of an inrush current value at the start of energization to a current value two seconds after the start of energization is 1.2 or higher. The control coil has a temperature resistance coefficient of five or higher. The control coil has a resistance value of 25 m© or higher at a portion between a front end of the control coil and L/2, where L is the length of the control coil in an axis direction. |
