Patents by Inventor Iwao Kunitomo

Iwao Kunitomo has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 9000658
    Abstract: A spark plug in which a front end portion of a ground electrode is positioned outside of a virtual outer circumferential face that is formed by extending a front and outer circumferential face of a center electrode in the axis direction, and positioned on a front end side in the axis direction with respect to a virtual face including a front end face of the center electrode. Further, the equation 1.1?b/a?1.6 is satisfied, where “a” (mm) represents a first minimal distance between the front end portion of the center electrode and the front end portion of the ground electrode and, where “b” (mm) represents a second minimal distance between the front end portion of a ceramic insulator and the front end portion of the ground electrode.
    Type: Grant
    Filed: April 3, 2009
    Date of Patent: April 7, 2015
    Assignee: NGK Spark Plug Co., Ltd.
    Inventors: Iwao Kunitomo, Kenji Ban
  • Patent number: 8047172
    Abstract: A plasma jet ignition plug capable of inhibiting occurrence of channeling while reducing removal of energy of plasma through a ground electrode at the time of emission of plasma. A ground electrode of a plasma jet ignition plug projects inward from a front end face of a metallic shell toward an opening end of a cavity which is open at a front end face of an insulator. A projecting distal end which forms a spark discharge gap between the same and a center electrode within a cavity is located inward, with respect to a diametral direction P orthogonal to an axis O, of a position which is located 0.5 mm radially outward from the opening end of the cavity.
    Type: Grant
    Filed: February 5, 2009
    Date of Patent: November 1, 2011
    Assignee: NGK Spark Plug Co., Ltd.
    Inventors: Toru Nakamura, Yuichi Yamada, Iwao Kunitomo, Yoshikuni Sato, Daisuke Nakano
  • Publication number: 20110025186
    Abstract: A spark plug in which a front end portion of a ground electrode is positioned outside of a virtual outer circumferential face that is formed by extending a front and outer circumferential face of a center electrode in the axis direction, and positioned on a front end side in the axis direction with respect to a virtual face including a front end face of the center electrode. Further, the equation 1.1?b/a?1.6 is satisfied, where “a” (mm) represents a first minimal distance between the front end portion of the center electrode and the front end portion of the ground electrode and, where “b” (mm) represents a second minimal distance between the front end portion of a ceramic insulator and the front end portion of the ground electrode.
    Type: Application
    Filed: April 3, 2009
    Publication date: February 3, 2011
    Applicant: NGK SPARK PLUG CO., LTD.
    Inventors: Iwao Kunitomo, Kenji Ban
  • Patent number: 7663296
    Abstract: A spark plug including: a cylindrical insulator having an axial hole extending through the insulator in an axial direction; a center electrode inserted in the axial hole; a metal shell provided around an outer periphery of the insulator and having a leading end surface, from which a leading end surface of the insulator protrudes; a ground electrode having a base end bonded to the leading end surface of the metal shell; and a noble metal tip disposed on a distal end of the ground electrode, an end of the noble metal tip protruding toward the center electrode in a radial direction, wherein: the spark plug forming a spark discharge path upon application of a discharging voltage between the protruding end of the noble metal tip and an end of the center electrode, the spark discharge path including an aerial discharge gap between a part of the protruding end of the noble metal tip and a part of the end of the insulator and a surface-creeping discharge path beginning at a part of the end of the insulator and a part
    Type: Grant
    Filed: March 29, 2007
    Date of Patent: February 16, 2010
    Assignee: NGK Spark Plug Co., Ltd.
    Inventors: Iwao Kunitomo, Yoshihiro Matsubara, Hironobu Mizutani
  • Publication number: 20090194053
    Abstract: A plasma jet ignition plug capable of inhibiting occurrence of channeling while reducing removal of energy of plasma through a ground electrode at the time of emission of plasma. A ground electrode of a plasma jet ignition plug projects inward from a front end face of a metallic shell toward an opening end of a cavity which is open at a front end face of an insulator. A projecting distal end which forms a spark discharge gap between the same and a center electrode within a cavity is located inward, with respect to a diametral direction P orthogonal to an axis O, of a position which is located 0.5 mm radially outward from the opening end of the cavity.
    Type: Application
    Filed: February 5, 2009
    Publication date: August 6, 2009
    Inventors: Toru Nakamura, Yuichi Yamada, Iwao Kunitomo, Yoshikuni Sato, Daisuke Nakano
  • Publication number: 20070228916
    Abstract: A spark plug including: a cylindrical insulator having an axial hole extending through the insulator in an axial direction; a center electrode inserted in the axial hole; a metal shell provided around an outer periphery of the insulator and having a leading end surface, from which a leading end surface of the insulator protrudes; a ground electrode having a base end bonded to the leading end surface of the metal shell; and a noble metal tip disposed on a distal end of the ground electrode, an end of the noble metal tip protruding toward the center electrode in a radial direction, wherein: the spark plug forming a spark discharge path upon application of a discharging voltage between the protruding end of the noble metal tip and an end of the center electrode, the spark discharge path including an aerial discharge gap between a part of the protruding end of the noble metal tip and a part of the end of the insulator and a surface-creeping discharge path beginning at a part of the end of the insulator and a part
    Type: Application
    Filed: March 29, 2007
    Publication date: October 4, 2007
    Applicant: NGK SPARK PLUG CO., LTD.
    Inventors: Iwao Kunitomo, Yoshihiro Matsubara, Hironobu Mizutani
  • Patent number: 5831377
    Abstract: In a spark plug including a cylindrical metal shell whose inner wall has a ledge portion, an insulator having a seat portion which engages with a rear slope surface of the ledge portion to be supported within the metal shell, a center electrode supported with an axial bore of the insulator, and a ground electrode extended from the metal shell to form a spark gap with the center electrode. A dimensional relationship among (A), (B) and (g) is defined as follows: {(B-A)/2}.gtoreq.0.8.times.(g) or {(B-A)/2}.gtoreq.0.9.times.(g). Where B (mm) is an inner diameter of a metal shell portion which surrounds an insulator nose, A (mm) is a base diameter of the insulator nose, and g (mm) is a width dimension of the spark gap.
    Type: Grant
    Filed: February 13, 1997
    Date of Patent: November 3, 1998
    Assignee: NGK Spark Plug Co, Ltd.
    Inventors: Yoshihiro Matsubara, Iwao Kunitomo, Wataru Matsutani
  • Patent number: 5680002
    Abstract: In a multi-polarity type spark plug for an internal combustion engine, a tubular insulator is supported within a cylindrical metallic shell through which a spark plug is to be attached to an internal combustion engine. A center electrode is placed within the insulator, a front end of the center electrode being directed toward a combustion chamber of the internal combustion engine from a front end of the metallic shell so as to extend beyond a front end of the insulator. First and second ground electrodes are each connected to the front end of the metallic shell, the first ground electrode forming a first vertical spark gap with a front end surface of the center electrode which directly opposes an elevational side of the center electrode, and the second ground electrode forming a second horizontal spark gap with an elevational side of the center electrode. An angle .theta.a is limited as 60.degree..ltoreq..theta.a .ltoreq.150.degree. in which the angle .theta.
    Type: Grant
    Filed: January 26, 1996
    Date of Patent: October 21, 1997
    Assignee: NGK Spark Plug Co., Ltd.
    Inventors: Iwao Kunitomo, Yoshihiro Matsubara, Kozo Amano