| 摘要 |
PROBLEM TO BE SOLVED: To improve the energization durability and the rapid temperature rise performance of a glow plug.SOLUTION: A glow plug (10) has a heater element (800) which comprises a cylindrical sheath tube (810), energization coils (820, 830) which have spirally-wound strands, are accommodated in the sheath tube, and generate power by being energized, and insulation powder (840) which is filled to the surroundings of the energization coils in the sheath tube. Each energization coil has a heterogeneous part selected from a first heterogeneous part which is a region in which a shape of a cross section including an axial line of the strand is changed in a winding direction, and the shape of the cross section is changed to a substantially-circular shape, a substantially-ellipse shape and the substantially-circular shape during one winding of the coil, and a second heterogeneous part in which the shape of the cross section is changed to the substantially-ellipse shape, the substantially-circular shape and the substantially-ellipse shape during one winding of the coil. In the substantially-circular shape, a ratio of a length of a major axis with respect to a minor axis is 1.0 to 1.2, and in the ellipse shape, a ratio of a length of a major axis with respect to a minor axis is not smaller than 1.4. |
