Patents by Inventor Tatsuya GOZAWA

Tatsuya GOZAWA 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: 11005236
    Abstract: A spark plug wherein the occurrence of cracks at a joint portion between a cover portion and a metal shell in the spark plug is prevented. The spark plug includes a cylindrical metal shell that accommodates an insulator therein, and a cover portion that covers, from a front end side of the spark plug, a front end portion of a center electrode and a facing portion of a ground electrode to form a pre-chamber space. The cover portion is joined to a front end side of the metal shell and has injection holes that are through-holes. A first coefficient of thermal expansion A (10?5/K) of the material forming the cover portion at normal temperature and a second coefficient of thermal expansion B (10?5/K) of the metal shell at normal temperature satisfy a formula (1): A<B.
    Type: Grant
    Filed: March 31, 2020
    Date of Patent: May 11, 2021
    Assignee: NGK SPARK PLUG CO., LTD.
    Inventor: Tatsuya Gozawa
  • Patent number: 10944244
    Abstract: A spark plug includes a plug cap having a plurality of through holes. In a cross section including an axial line, the plug cap includes an enlarging portion in a portion of a region between a first imaginary straight line and a second imaginary straight line, the first imaginary straight line extending through a front end of the end portion of a ground electrode and being perpendicular to the axial line, the second imaginary straight line extending through a back end of one of inner open ends of the through holes that is closest to a front end of the spark plug and being perpendicular to the axial line. The enlarging portion being a portion in which a minimum distance from an outer surface to an inner surface of the plug cap increases with increasing distance in a direction from back to front.
    Type: Grant
    Filed: March 11, 2020
    Date of Patent: March 9, 2021
    Assignee: NGK SPARK PLUG CO., LTD.
    Inventors: Kenji Ban, Tatsuya Gozawa
  • Patent number: 10910796
    Abstract: A spark plug includes: a center electrode; a ground electrode that is provided such that a gap for spark discharge is formed between the center electrode and the ground electrode; and a plug cover covering the center electrode and the ground electrode from a front side to form an auxiliary chamber, the plug cover being provided with a through hole, wherein 60% or more of the auxiliary chamber is present in a sphere. The sphere t has a center at a midpoint of a line segment connecting the center electrode and the ground electrode at a shortest distance on an axial line of the center electrode and is in contact with a point located closest from the center on an inner open end of the through hole is imagined.
    Type: Grant
    Filed: May 7, 2020
    Date of Patent: February 2, 2021
    Assignee: NGK SPARK PLUG CO., LTD.
    Inventor: Tatsuya Gozawa
  • Patent number: 10868408
    Abstract: A spark plug that can suppress pre-ignition of a combustible air-fuel mixture that has flowed into the sub-chamber. The spark plug includes a ground electrode that joins to a metal shell and forms a spark gap; and a cap member that covers a center electrode and the ground electrode and forms a sub-chamber. A first fused portion that joins the metal shell and the cap member is located on the front-end side relative to the spark gap. At least a part of a first facing portion at which the metal shell and the cap member face each other is located on the sub-chamber side relative to the first fused portion. The first fused portion is not formed in an inner peripheral surface of the metal shell and an inner peripheral surface of the cap member.
    Type: Grant
    Filed: February 26, 2020
    Date of Patent: December 15, 2020
    Assignee: NGK SPARK PLUG CO., LTD.
    Inventors: Tatsuya Gozawa, Kenji Ban
  • Patent number: 10847951
    Abstract: A spark plug includes: a center electrode; a ground electrode that is provided such that a gap for spark discharge is formed between the center electrode and the ground electrode; and a plug cover covering the center electrode and the ground electrode to form an auxiliary chamber. The plug cover is provided with plural through holes. A relationship of 80<A/B<5000 is satisfied, where a sphere has a center at a midpoint of a line connecting the center electrode and the ground electrode at a shortest distance on an axial line and contacts a point located closest from the center on each of inner open ends of the through holes. A mm3 is a volume of a region of the auxiliary chamber, which is present in the sphere, and B mm2 is an average area of the inner open ends of the through holes.
    Type: Grant
    Filed: May 7, 2020
    Date of Patent: November 24, 2020
    Assignee: NGK SPARK PLUG CO., LTD.
    Inventors: Tatsuya Gozawa, Daiki Goto
  • Publication number: 20200358260
    Abstract: A spark plug wherein the occurrence of cracks at a joint portion between a cover portion and a metal shell in the spark plug is prevented. The spark plug includes a cylindrical metal shell that accommodates an insulator therein, and a cover portion that covers, from a front end side of the spark plug, a front end portion of a center electrode and a facing portion of a ground electrode to form a pre-chamber space. The cover portion is joined to a front end side of the metal shell and has injection holes that are through-holes. A first coefficient of thermal expansion A (10?5/K) of the material forming the cover portion at normal temperature and a second coefficient of thermal expansion B (10?5/K) of the metal shell at normal temperature satisfy a formula (1): A<B.
    Type: Application
    Filed: March 31, 2020
    Publication date: November 12, 2020
    Applicant: NGK SPARK PLUG CO., LTD.
    Inventor: Tatsuya GOZAWA
  • Publication number: 20200358261
    Abstract: A spark plug includes: a center electrode; a ground electrode that is provided such that a gap for spark discharge is formed between the center electrode and the ground electrode; and a plug cover covering the center electrode and the ground electrode from a front side to form an auxiliary chamber, the plug cover being provided with a through hole, wherein 60% or more of the auxiliary chamber is present in a sphere. The sphere t has a center at a midpoint of a line segment connecting the center electrode and the ground electrode at a shortest distance on an axial line of the center electrode and is in contact with a point located closest from the center on an inner open end of the through hole is imagined.
    Type: Application
    Filed: May 7, 2020
    Publication date: November 12, 2020
    Applicant: NGK SPARK PLUG CO., LTD.
    Inventor: Tatsuya Gozawa
  • Publication number: 20200358259
    Abstract: A spark plug includes: a center electrode; a ground electrode that is provided such that a gap for spark discharge is formed between the center electrode and the ground electrode; and a plug cover covering the center electrode and the ground electrode to form an auxiliary chamber. The plug cover is provided with plural through holes. A relationship of 80<A/B<5000 is satisfied, where a sphere has a center at a midpoint of a line connecting the center electrode and the ground electrode at a shortest distance on an axial line and contacts a point located closest from the center on each of inner open ends of the through holes. A mm3 is a volume of a region of the auxiliary chamber, which is present in the sphere, and B mm2 is an average area of the inner open ends of the through holes.
    Type: Application
    Filed: May 7, 2020
    Publication date: November 12, 2020
    Applicant: NGK SPARK PLUG CO., LTD.
    Inventors: Tatsuya Gozawa, Daiki Goto
  • Patent number: 10833486
    Abstract: A spark plug having excellent ignitability including a rod-shaped center electrode; a ground electrode that includes a facing portion facing a front end portion of the center electrode and forms a discharge gap between the facing portion and the front end portion of the center electrode; an insulator; a metal shell; and a cover portion that covers, from a front end side of the spark plug, the front end portion of the center electrode and the facing portion of the ground electrode to form a pre-chamber and includes injection holes that are through holes.
    Type: Grant
    Filed: March 10, 2020
    Date of Patent: November 10, 2020
    Assignee: NGK SPARK PLUG CO., LTD.
    Inventors: Tatsuya Gozawa, Kenji Ban, Daiki Goto
  • Publication number: 20200335949
    Abstract: A spark plug having excellent ignitability including a rod-shaped center electrode; a ground electrode that includes a facing portion facing a front end portion of the center electrode and forms a discharge gap between the facing portion and the front end portion of the center electrode; an insulator; a metal shell; and a cover portion that covers, from a front end side of the spark plug, the front end portion of the center electrode and the facing portion of the ground electrode to form a pre-chamber and includes injection holes that are through holes.
    Type: Application
    Filed: March 10, 2020
    Publication date: October 22, 2020
    Applicant: NGK SPARK PLUG CO., LTD.
    Inventors: Tatsuya GOZAWA, Kenji BAN, Daiki GOTO
  • Patent number: 10811851
    Abstract: A spark plug includes: a center electrode; a ground electrode that is provided such that a gap for spark discharge is formed between the center electrode and the ground electrode; and a plug cover covering the center electrode and the ground electrode from a front side. The plug cover has a through hole, wherein the plug cover includes a diameter reduction portion formed in a range of 0.1 mm or less from an outer open end of the through hole in a direction along a central axis of the through hole and having a diameter gradually decreasing from the outer open end toward an inner open end of the through hole. A relationship of 0 mm<x?y<0.2 mm is satisfied, where x is a diameter at the outer open end, and y is a diameter at an inner end of the diameter reduction portion.
    Type: Grant
    Filed: May 19, 2020
    Date of Patent: October 20, 2020
    Assignee: NGK SPARK PLUG CO., LTD.
    Inventors: Tatsuya Gozawa, Kenji Ban
  • Publication number: 20200295540
    Abstract: A spark plug includes a plug cap having a plurality of through holes. In a cross section including an axial line, the plug cap includes an enlarging portion in a portion of a region between a first imaginary straight line and a second imaginary straight line, the first imaginary straight line extending through a front end of the end portion of a ground electrode and being perpendicular to the axial line, the second imaginary straight line extending through a back end of one of inner open ends of the through holes that is closest to a front end of the spark plug and being perpendicular to the axial line. The enlarging portion being a portion in which a minimum distance from an outer surface to an inner surface of the plug cap increases with increasing distance in a direction from back to front.
    Type: Application
    Filed: March 11, 2020
    Publication date: September 17, 2020
    Applicant: NGK SPARK PLUG CO., LTD.
    Inventors: Kenji BAN, Tatsuya GOZAWA
  • Patent number: 10777976
    Abstract: A spark plug wherein the occurrence of pre-ignition and misfires is suppressed. The spark plug includes a cover portion that covers a front end portion of a center electrode and a facing portion of a ground electrode from a front end side of the spark plug to form a pre-chamber space. The cover portion has injection holes that are through-holes. A total area A (mm2) of inner peripheral surfaces of the injection holes and a thermal conductivity B (W/mK) of a material of the cover portion satisfy a formula (1): 10<A×B<4000.
    Type: Grant
    Filed: April 14, 2020
    Date of Patent: September 15, 2020
    Assignee: NGK SPARK PLUG CO., LTD.
    Inventors: Tatsuya Gozawa, Kenji Ban, Daiki Goto
  • Publication number: 20200287358
    Abstract: A spark plug that can suppress pre-ignition of a combustible air-fuel mixture that has flowed into the sub-chamber. The spark plug includes a ground electrode that joins to a metal shell and forms a spark gap; and a cap member that covers a center electrode and the ground electrode and forms a sub-chamber. A first fused portion that joins the metal shell and the cap member is located on the front-end side relative to the spark gap. At least a part of a first facing portion at which the metal shell and the cap member face each other is located on the sub-chamber side relative to the first fused portion. The first fused portion is not formed in an inner peripheral surface of the metal shell and an inner peripheral surface of the cap member.
    Type: Application
    Filed: February 26, 2020
    Publication date: September 10, 2020
    Applicant: NGK SPARK PLUG CO., LTD.
    Inventors: Tatsuya GOZAWA, Kenji BAN
  • Patent number: 10770868
    Abstract: A spark plug wherein both pre-ignition and misfires are suppressed. The spark plug includes a center electrode; a ground electrode; a cylindrical insulator; a metal shell that accommodates the insulator therein; and a cover portion that covers a front end portion of the center electrode and a facing portion of the ground electrode to form a pre-chamber. The insulator includes an outer peripheral surface exposed to the pre-chamber, the cover portion includes a portion exposed to the pre-chamber, and the metal shell includes a portion exposed to the pre-chamber. When a surface area of the outer peripheral surface is a first surface area A (mm2), and a total surface area of the portion of the cover portion and the portion of the metal shell is a second surface area B (mm2), the spark plug satisfies a relational expression 1:0.10<A/B<0.70.
    Type: Grant
    Filed: April 7, 2020
    Date of Patent: September 8, 2020
    Assignee: NGK SPARK PLUG CO., LTD.
    Inventor: Tatsuya Gozawa
  • Patent number: 10742002
    Abstract: A spark plug wherein the occurrence of pre-ignition and misfires in the spark plug are suppressed. The spark plug includes a cover portion, that covers a front end portion of a center electrode and a facing portion of a ground electrode from a front end side of the spark plug to form a pre-chamber space. The cover portion has injection holes that are through-holes. A metal shell volume A (mm3) of a portion of the metal shell on the front side with respect to a rear end of the pre-chamber space and a thermal conductivity B (W/mK) of the metal shell at the normal temperature satisfy a formula (1): 3.6<A/B<98.0. The metal shell volume A (mm3) and a space volume C of the pre-chamber space satisfy a formula (2): 0.18<C/A<1.20.
    Type: Grant
    Filed: April 1, 2020
    Date of Patent: August 11, 2020
    Assignee: NGK SPARK PLUG CO., LTD.
    Inventors: Tatsuya Gozawa, Daiki Goto
  • Patent number: 10714908
    Abstract: A spark plug includes a center electrode; a metal shell that retains the center electrode at an outer periphery of the center electrode in an insulating manner; a ground electrode disposed such that a spark gap is formed between the center electrode and an end portion of the ground electrode; and a plug cap connected to the metal shell, the plug cap covering the center electrode and the end portion of the ground electrode from front and having a through hole in a region in front of the ground electrode. An inner surface of the plug cap has at least one ridge in a first region that is in front of an inner open end of the through hole.
    Type: Grant
    Filed: April 9, 2020
    Date of Patent: July 14, 2020
    Assignee: NGK Spark Plug Co., Ltd.
    Inventors: Tatsuya Gozawa, Kenji Ban
  • Patent number: 10714904
    Abstract: A spark plug includes: an insulator with an axial hole; a center electrode held in a front end side of the axial hole; a cylindrical metal shell disposed around the insulator and having a seal part brought into contact with an outer circumferential surface of the insulator; a ground electrode arranged to form a gap with the center electrode; and a cap connected to a front end part of the metal shell to define therein an auxiliary combustion space in which the gap is formed, the cap having at least one through hole formed to provide communication between the auxiliary combustion space and the outside, wherein the condition (B/A)?0.25 is satisfied where A represents a volume of an imaginary space defined at a position frontward of the seal part; and B represents a volume of parts of the ground and center electrodes located in the imaginary space.
    Type: Grant
    Filed: August 23, 2019
    Date of Patent: July 14, 2020
    Assignee: NGK SPARK PLUG CO., LTD.
    Inventor: Tatsuya Gozawa
  • Patent number: 10666023
    Abstract: A spark plug includes: a center electrode; an insulating member; a metal shell; a ground electrode; and a cap covers an opening of the metal shell on the front end side to define an auxiliary combustion space in which the gap is disposed, a first angle being formed by a second line and a first tangent line, a second angle being formed by the second line and a second tangent line, the second angle being greater than the first angle, and at least a portion of the opening of the specific through hole on the auxiliary combustion space side being positioned on a range of the second angle.
    Type: Grant
    Filed: June 28, 2019
    Date of Patent: May 26, 2020
    Assignee: NGK SPARK PLUG CO., LTD.
    Inventor: Tatsuya Gozawa
  • Publication number: 20200106246
    Abstract: A spark plug includes: an insulator with an axial hole; a center electrode held in a front end side of the axial hole; a cylindrical metal shell disposed around the insulator and having a seal part brought into contact with an outer circumferential surface of the insulator; a ground electrode arranged to form a gap with the center electrode; and a cap connected to a front end part of the metal shell to define therein an auxiliary combustion space in which the gap is formed, the cap having at least one through hole formed to provide communication between the auxiliary combustion space and the outside, wherein the condition (B/A)?0.25 is satisfied where A represents a volume of an imaginary space defined at a position frontward of the seal part; and B represents a volume of parts of the ground and center electrodes located in the imaginary space.
    Type: Application
    Filed: August 23, 2019
    Publication date: April 2, 2020
    Applicant: NGK SPARK PLUG CO., LTD.
    Inventor: Tatsuya GOZAWA