摘要:
A spark plug is composed of a main metal fitting having a cylindrical structure, an insulator disposed inside the cylindrical main metal fitting, a center electrode fitted in the insulator in a manner that a front end portion of the center electrode projects outward over one end of the insulator, and a grounding electrode mounted to the main metal fitting and having one end portion opposing to the front end portion of the center electrode through a discharge gap therebetween. The front end portion of the center electrode includes a conical portion having a tapered surface having a taper angle of less than 80°, and a columnar portion formed to a top end portion of the conical portion so as to have a diameter in a range of 0.4 mm to 0.8 mm.
摘要:
A small-sized spark plug is provided which ensures the stability in the location of production of sparks between center and ground electrodes. The center and ground electrodes have joined thereon cylindrical members such as noble metal chips which are opposed to each other through a spark gap. The cylindrical members are so oriented to have longitudinal center lines extend parallel in misalignment with each other. This orientation results in shorter and longer intervals between end surfaces of the cylindrical members. The sparks are concentrated between portions of edges of cylindrical members located apart the shorter interval, thereby resulting in the stability in the location of production of the sparks.
摘要:
A small-sized spark plug is provided which ensures the stability in the location of production of sparks between center and ground electrodes. The center and ground electrodes have joined thereon cylindrical members such as noble metal chips which are opposed to each other through a spark gap. The cylindrical members are so oriented to have longitudinal center lines extend parallel in misalignment with each other. This orientation results in shorter and longer intervals between end surfaces of the cylindrical members. The sparks are concentrated between portions of edges of cylindrical members located apart the shorter interval, thereby resulting in the stability in the location of production of the sparks.
摘要:
Carbon fouling adhered on an insulator tip of a spark plug of the present invention is burnt down by a leak current during an inductive discharge period, due to a promoted ionization before beginning a capacitive discharge, in such an arrangement of a central electrode that a border portion of a body and narrowed portion is positioned in an insulator. The carbon burning-down effect is further improved by a narrow projection provided with an earth electrode, due to increased inductive energy and extended inductive discharge time period. This is because an electric field in a discharge gap is raised, thereby decreasing a discharge voltage and suppressing an energy emitted from a coil during the capacitive discharge.
摘要:
A spark plug according to the present invention includes a metal shell, an insulator, a cylindrical center electrode, a first ground electrode, and a second ground electrode. The first ground electrode is aligned with the center electrode in the axial direction of the center electrode to form a first spark gap, across which normal sparks are discharged when the insulator is not fouled with carbon. The second ground electrode is aligned with the center electrode in the radial direction of the center electrode to form a second spark gap, across which side sparks are discharged when the insulator is fouled with carbon. The spark plug has an improved structure where dimensional parameters A, T, B, C, L, D, and E are specified to be in suitable ranges that are determined through experimental investigation. The improved structure ensures a high ignition capability and a long service life of the spark plug.
摘要:
A spark plug according to the invention includes a metal shell, a hollow insulator, a center electrode, and a ground electrode. The insulator has a first end protruding into a combustion chamber of an engine and a second end opposite to the first end in the lengthwise direction of the insulator. The insulator increases in outer diameter from the edge of the inner surface thereof at the first end to a reference plane that is defined to extend perpendicular to the lengthwise direction of the insulator and away 0.1 mm from the edge of the inner surface of the insulator toward the second end of the same in the lengthwise direction. Further, a first volume V1, which is the volume of a portion of the insulator between the edge of the inner surface of the insulator and the reference plane, is in the range of 0.15 to 0.38 mm3.
摘要:
A spark plug according to the present invention includes a metal shell, an insulator, a cylindrical center electrode, a first ground electrode, and a second ground electrode. The first ground electrode is aligned with the center electrode in the axial direction of the center electrode to form a first spark gap, across which normal sparks are discharged when the insulator is not fouled with carbon. The second ground electrode is aligned with the center electrode in the radial direction of the center electrode to form a second spark gap, across which side sparks are discharged when the insulator is fouled with carbon. The spark plug has an improved structure where dimensional parameters A, T, B, C, L, D, and E are specified to be in suitable ranges that are determined through experimental investigation. The improved structure ensures a high ignition capability and a long service life of the spark plug.
摘要:
A spark plug according to the invention includes a metal shell, a hollow insulator, a center electrode, and a ground electrode. The insulator has a first end protruding into a combustion chamber of an engine and a second end opposite to the first end in the lengthwise direction of the insulator. The insulator increases in outer diameter from the edge of the inner surface thereof at the first end to a reference plane that is defined to extend perpendicular to the lengthwise direction of the insulator and away 0.1 mm from the edge of the inner surface of the insulator toward the second end of the same in the lengthwise direction. Further, a first volume V1, which is the volume of a portion of the insulator between the edge of the inner surface of the insulator and the reference plane, is in the range of 0.15 to 0.38 mm3.
摘要:
A spark plug for an internal combustion engine is disclosed having a metal shell having an outer periphery formed with a mounting thread, a porcelain insulator fixedly secured to the metal shell on a central axis thereof, a center electrode retained within the porcelain insulator along a central axis thereof with a distal end located outside the porcelain insulator, and a ground electrode joined to the metal shell and having an end associated with the distal end of the center electrode to define therebetween a spark discharge gap. The ground electrode includes a facing surface intersecting the central axis of the center electrode and having a width equal to or less than 1.6 mm.
摘要:
A storage reduction NOx catalyst is disposed in an exhaust passage for an internal combustion engine. A NOx sensor is disposed upstream of the NOx catalyst. An inflow NOx amount, which is the amount of NOx that has flown into the NOx catalyst, is calculated by accumulating the output of the NOx sensor. A total storage amount, which is the sum of the amounts of oxygen and NOx stored in the NOx catalyst, is calculated based on an output generated by an exhaust gas sensor disposed downstream of the NOx catalyst when rich spike is being executed. The deterioration of the NOx catalyst is determined based on the inflow NOx amount and the total storage amount.