Spark plug including a ground electrode, a center electrode, and a resistor

摘要

In a spark plug for a gas engine including a ground electrode (4) whose front end is to be placed in a combustion chamber of a gas engine which is driven by gaseous fuel, a metallic shell (3) enclosing a center electrode (5) which has a noble metal tip (18) superior in spark-erosion resistance at a firing portion in which a spark discharge occurs against the ground electrode (4). A resistor (10) is provided within the spark plug or a spark plug cap so as to be included in a spark plug voltage circuit which applies a high voltage to the center electrode. It is preferable that the noble metal tip (18) has a diameter in a range of 0.5 DIFFERENCE 1.5 mm, and that the resistor has an electrical resistance greater than or equal to 50 k OMEGA .