A spark plug including a ground electrode including a base material, a tip having a discharge surface, and a melt portion interposed over an entire area between the tip and the base material and joining the tip to the base material; and a center electrode with a spark gap formed between the center electrode and the discharge surface. The tip has, in an inner area surrounded by an outer peripheral portion of the tip, a thin portion in which a distance between the discharge surface and the melt portion is shorter than a distance between the discharge surface and the melt portion in the outer peripheral portion. The thin portion extends from a part of the outer peripheral portion to a part other than the part of the outer peripheral portion.

An apparatus for setting a gap between a first electrode and a second electrode of a spark plug, encompassing at least a counter-brace, a gap plate, and a plunger, which are disposed along a longitudinal axis; the counter-brace being configured to brace the spark plug; the gap plate being disposed between the counter-brace and the plunger in the direction of the longitudinal axis; the gap plate being configured to be disposed between the first electrode and the second electrode; and the plunger being configured to apply a deformation force in the direction of the longitudinal axis onto the second electrode.

An apparatus for setting a gap between a first electrode and a second electrode of a spark plug, encompassing at least a counter-brace, a gap plate, and a plunger, which are disposed along a longitudinal axis; the counter-brace being configured to brace the spark plug; the gap plate being disposed between the counter-brace and the plunger in the direction of the longitudinal axis; the gap plate being configured to be disposed between the first electrode and the second electrode; and the plunger being configured to apply a deformation force in the direction of the longitudinal axis onto the second electrode.

System and methods for operating a vehicle that includes a boosted engine are described. In one example, a spark plug may be adjusted between two operating states to reduce a possibility of pre-ignition and spark plug fouling. A first operating state may be conducive to operating the engine at light loads. The first operating state may be conducive to operating the engine at higher loads.

A first member and a second member are held by being sandwiched by first and second holders. By providing force, which brings N nails (N is an integer that is 2 or greater) of chucks closer to each other, to the N nails, each of L nails contacts the first member without contacting the second member and each of M nails contacts the second member without contacting the first member. By separating the second holder from the second member, the N nails get even closer to each other, and the second member is moved relative to the first member, then a relative position of the first and second members is adjusted. By making the second holder contact with the second member again, the first and second members are held. After removing the chucks from the first and second members, a contact portion of the first and second members is laser-welded.

A first member and a second member are held by being sandwiched by first and second holders. By providing force, which brings N nails (N is an integer that is 2 or greater) of chucks closer to each other, to the N nails, each of L nails contacts the first member without contacting the second member and each of M nails contacts the second member without contacting the first member. By separating the second holder from the second member, the N nails get even closer to each other, and the second member is moved relative to the first member, then a relative position of the first and second members is adjusted. By making the second holder contact with the second member again, the first and second members are held. After removing the chucks from the first and second members, a contact portion of the first and second members is laser-welded.

A first member and a second member are held by being sandwiched by first and second holders. By providing force, which brings N nails (N is an integer that is 2 or greater) of chucks closer to each other, to the N nails, each of L nails contacts the first member without contacting the second member and each of M nails contacts the second member without contacting the first member. By separating the second holder from the second member, the N nails get even closer to each other, and the second member is moved relative to the first member, then a relative position of the first and second members is adjusted. By making the second holder contact with the second member again, the first and second members are held. After removing the chucks from the first and second members, a contact portion of the first and second members is laser-welded.

A first member and a second member are held by being sandwiched by first and second holders. By providing force, which brings N nails (N is an integer that is 2 or greater) of chucks closer to each other, to the N nails, each of L nails contacts the first member without contacting the second member and each of M nails contacts the second member without contacting the first member. By separating the second holder from the second member, the N nails get even closer to each other, and the second member is moved relative to the first member, then a relative position of the first and second members is adjusted. By making the second holder contact with the second member again, the first and second members are held. After removing the chucks from the first and second members, a contact portion of the first and second members is laser-welded.

System and methods for operating a vehicle that includes a boosted engine are described. In one example, a spark plug may be adjusted between two operating states to reduce a possibility of pre-ignition and spark plug fouling. A first operating state may be conducive to operating the engine at light loads. The first operating state may be conducive to operating the engine at higher loads.

Standard image data representing standard image including image of slit of a standard device is produced by photographing the standard device including the slit which includes a standard slit segment having a predetermined width. A width of the standard slit segment in the standard image is determined by analyzing the standard image data. Gap image data representing a gap image which is an image including an image of a discharge gap of a spark plug is produced by photographing the spark plug. A distance of the discharge gap in the gap image is determined by analyzing the gap image data. By using the distance of the discharge gap in the gap image and the width of the standard slit segment in the standard image, it is determined whether an actual distance of the discharge gap is within a predetermined allowable range or not.