IGNITION COIL FOR INTERNAL COMBUSTION ENGINE

• US 20170321648A1
• Filed: 11/06/2015
• Published: 11/09/2017
• Est. Priority Date: 11/11/2014
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: SANO, Masafuyu, WADA, Junichi
• Granted Patent: US 10,012,203 B2
• Time in Patent Office: Days
• CPC Class Codes: F02P 13/00 Sparking plugs structurally combined with other parts of internal-combustion engines connection of ignition coil to spark plug connector F02P3/02; with fuel injectors F02M57/06 ; spark plug connector per se H01T13/04 – H01T13/06; predominant aspects of sparking plug, see H01T13/40 – H01T13/44
• CPC Class Codes: F02P 15/12 having means for strengthening spark during starting
• CPC Class Codes: F02P 3/02 having inductive energy storage, e.g. arrangements of induction coils ignition coils structurally combined with sparking plugs F02P13/00; constructional details of ignition coils H01F38/12
• CPC Class Codes: F02P 3/0556 Protecting the coil when the engine is stopped
• CPC Class Codes: F02P 9/007 by supplementary electrical discharge in the pre-ionised electrode interspace of the sparking plug, e.g. plasma jet ignition
• CPC Class Codes: H01F 27/306 Fastening or mounting coils or windings on core, casing or other support
• CPC Class Codes: H01F 27/425 for voltage transformers
• CPC Class Codes: H01F 38/12 Ignition, e.g. for IC engines

Abstract

In an ignition coil for an internal combustion engine, a resistor is disposed in a tower insertion hole of a high-voltage tower section. A coil spring is inserted in the tower insertion hole. An inner diameter of a proximal end side portion of the tower insertion hole is larger than an outer diameter of a maximum outer diameter portion of the resistor. An inner diameter of the distal end side portion of the tower insertion hole is larger than an outer diameter of a proximal end side portion of the coil spring, and is smaller than the outer diameter of the maximum outer diameter portion. In a state where the coil spring is pulled out from the tower insertion hole, the maximum outer diameter portion is restrained by the distal end side portion of the tower insertion hole, and a gap is formed between the resistor and a high-voltage cap.

Claims

1. An ignition coil for an internal combustion engine, the ignition coil comprising:

a primary coil and a secondary coil;

a coil case that includes a housing section and a high-voltage tower section, the housing section housing the primary coil and the secondary coil, the housing section being arranged outside a plug hole of a cylinder for an internal combustion engine in which an ignition plug is arranged, the high-voltage tower section being disposed in the housing section such that at least a section of the high-voltage tower section is located within the plug hole;

a rubber seal that is attached to an outer periphery of the high-voltage tower section;

a pole joint that is arranged within the plug hole and attached to the high-voltage tower section via the rubber seal;

a resistor that is disposed in a tower insertion hole formed in a central portion of the high-voltage tower section;

a coil spring that is continuously inserted in a joint insertion hole formed in the pole joint and a distal end side portion of the tower insertion hole to be in contact with the resistor; and

a high-voltage cap that is attached to a proximal end side of the high-voltage tower section, and allows the resistor and a high-voltage winding end portion of the secondary coil to be electrically connected to each other, wherein;

an inner diameter of a proximal end side portion of the tower insertion hole is larger than an outer diameter of a maximum outer diameter portion of the resistor;

an inner diameter of the distal end side portion of the tower insertion hole is larger than an outer diameter of a proximal end side portion of the coil spring and is equal to or smaller than the outer diameter of the maximum outer diameter portion of the resistor; and

the ignition coil is configured such that in a state where the coil spring is pulled out from the tower insertion hole, the maximum outer diameter portion of the resistor is restrained by the distal end side portion of the tower insertion hole, and a gap is formed between the resistor and the high-voltage tower section.

2. The ignition coil for an internal combustion engine according to claim 1, wherein:

the insertion hole includes a tapered hole section having a diameter that is reduced from an proximal end side toward an distal end side;

the proximal end side portion of the tower insertion hole is formed by including a proximal end side portion of the tapered hole section; and

the distal end side portion of the tower insertion hole is formed by a distal end side portion of the tapered hole section.

3. The ignition coil for an internal combustion engine according to claim 2, wherein:

a tapered outer peripheral section is formed in an outer peripheral side of a position at which at least the tapered hole section is formed in an outer peripheral surface of the high-voltage tower section, the tapered outer peripheral section having a diameter that is reduced from an proximal end side toward an distal end side.

4. The ignition coil for an internal combustion engine according to claim 2, wherein:

a straight hole section is formed in a distal end side of the tapered hole section, the straight hole section having an inner diameter that is equal to an inner diameter of a distal end position of the tapered hole section.

5. The ignition coil for an internal combustion engine according to claim 3, wherein:

a straight hole section is formed in a distal end side of the tapered hole section, the straight hole section having an inner diameter that is equal to an inner diameter of a distal end position of the tapered hole section.