| 摘要 |
Provided is a glow plug in which long-term disconnection due to a decrease in the resistance value caused by a lowered Al concentration in a heat-generating coil can be prevented, and short-term disconnection of the heat-generating coil due to an excessive temperature increase during a rapid temperature increase can be prevented, thus lengthening the burn-out life. This glow plug has a coil accommodated in a tube, wherein the coil has a heat-generating coil formed from an Ni-Cr alloy and disposed at the tip end of the tube, and a control coil connected to the rear end of the tube. The normal temperature resistance value is 300 mOmega to 500 mOmega. The cumulative amount of heat generated by the heat-generating coil for two seconds after the start of current conduction is 400 W or less. The ratio between the incoming current value at the start of current conduction and the current value two seconds after the start of current conduction is 1.2 or greater. The temperature resistance coefficient of the control coil is 5 or greater. If L indicates the axial length of the control coil, the resistance value in the region from the tip end of the control coil up to L/2 is 25 mOmega or greater. |
