| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a spark plug having a low fuel consumption at a low cost. <P>SOLUTION: In the spark plug where the screw diameter of a threaded portion is 14 mm, following relation is satisfied; 0.371X<SB POS="POST">1</SB><SP POS="POST">2</SP>+1.151X<SB POS="POST">2</SB><SP POS="POST">2</SP>-1.005X<SB POS="POST">1</SB>-9.019X<SB POS="POST">2</SB>+0.053X<SB POS="POST">3</SB>+17.782≤0 where 1.0≤X<SB POS="POST">1</SB>≤4.2, 3.1≤X<SB POS="POST">2</SB>≤4.0, 1.0≤X<SB POS="POST">3</SB>≤1.8, when the width is X<SB POS="POST">1</SB>(mm), the length of the inner side surface is X<SB POS="POST">2</SB>(mm), and the thickness is X<SB POS="POST">3</SB>(mm), of a portion from the horizontal surface along the tip of the center electrode out of a ground electrode to the vertical surface along the center electrode side surface on the ground electrode side. <P>COPYRIGHT: (C)2013,JPO&INPIT |
