Ignition coil unit and ignition system, capable of suppressing deformation of the seal section, used in internal combustion engine

Patent metadata

Field	Value
Publication number	US-10815957-B2
Application number	US-201916448428-A
Country	US
Kind code	B2
Filing date	Jun 21, 2019
Priority date	Jun 26, 2018
Publication date	Oct 27, 2020
Grant date	Oct 27, 2020

Abstract

An ignition coil unit is attached to an engine body. The engine body includes a cylinder head having a plug hole and a head cover that covers the cylinder head by including an opening hole facing the plug hole. The ignition coil unit includes a coil unit that generates a high voltage and a cylindrical coupling unit that connects the coil unit with a spark plug. The coupling unit includes a flexible sealing section fitting to an outer peripheral surface of the high tension tower and a harder joint fitting to a tip of the sealing section. The sealing section includes an adhesion portion to tightly contact the head cover and a neck portion at least between the adhesion portion and the joint in a Z-axis direction. The neck portion is formed by partially constricting an outer peripheral surface of the sealing section radially inside.

First claim

What is claimed is:

1. An ignition coil unit used in an internal combustion engine as an attachment to an engine body that includes a cylinder head having a plug hole and a head cover that covers the cylinder head by including an opening hole facing the plug hole, the ignition coil unit comprising:
a coil unit to generate a high voltage, the coil unit including;
a main housing to accommodate components used in the coil unit, and
an auxiliary housing to accommodate a cylindrical high tension tower protruding from the main housing to a tip side in an axial direction; and

a cylindrical coupling unit to couple the coil unit to a spark plug,
the cylindrical coupling unit including;
a flexible sealing section extending in an axial direction of the cylindrical coupling unit while fitting to an outer peripheral surface of the high tension tower,
the flexible sealing section including:
a first fitting section at a tip of the flexible sealing section, and
an adhesion portion to tightly contact the head cover, and

a joint aligning with the flexible sealing section in the axial direction,
the joint having a second fitting section fitting to the first fitting section of the flexible sealing section, the joint being harder than the sealing section,

wherein the flexible sealing section further includes a neck portion at least in a region between the adhesion portion and the joint in the axial direction,
wherein the neck portion is formed by partially narrowing the sealing section radially inwardly.

2. The ignition coil unit as claimed in claim 1 , wherein the high tension tower includes a retainer located on a base end side in the axial direction relative to the joint to prevent removal of the sealing section, the retainer projecting radially outward,
wherein the sealing section includes a recess to accommodate the retainer, wherein the neck portion is located at a position to overlap with the recess in the radial direction.

3. The ignition coil unit as claimed in claim 1 , wherein the sealing section includes a convex portion at a position adjacent to a tip of the neck portion in the axial direction, the convex portion extending radially outside from an outer peripheral surface of the sealing section.

4. The ignition coil unit as claimed in claim 1 , wherein the neck portion includes a prescribed length in the axial direction.

5. The ignition coil unit as claimed in claim 1 , wherein the sealing section has a minimum diameter at the neck portion.

6. The ignition coil unit as claimed in claim 1 , wherein the joint fitting section is cylindrical and includes:
an inner peripheral step inclining radially outward as an inner peripheral surface approaches a base end of the sealing section in the axial direction, and
a base end inner peripheral surface extending from an end of the inner peripheral step to the base end,
wherein a cavity is formed in a radial direction at least between either the inner peripheral step or the base end inner peripheral surface and the sealing section.

7. An ignition system comprising:
a cylinder head having a plug hole;
a head cover to cover the cylinder head, the head cover having an opening hole facing the plug hole; and
an ignition coil unit inserted into both of the plug hole and the opening hole,
the ignition coil unit including,
a coil unit to generate a high voltage, the coil unit including,
a main housing to accommodate components used in the coil unit, and
an auxiliary housing to accommodate a cylindrical high tension tower protruding from the main housing to a tip side in an axial direction, and

a cylindrical coupling unit extending in its axial direction to couple the coil unit to a spark plug while fitting to an outer peripheral surface of the cylindrical high tension tower,
the cylindrical coupling unit including,
an adhesion portion to tightly contact the head cover, and
a neck portion on a tip side relative to the adhesion portion,

wherein the neck portion is at least partially placed inside an opening end of the plug hole located on a base end side in the axial direction,
wherein the neck portion is formed by partially narrowing the sealing section radially inside.

8. The ignition system as claimed in claim 7 , wherein the coupling unit includes:
a flexible sealing section fitting to the outer peripheral surface of the high tension tower, the sealing section including a first fitting section at a tip of the sealing section; and
a joint harder than the sealing section, the joint having a second fitting section fitting to the first fitting section,
wherein the neck portion is formed in the sealing section at least between the adhesion portion and the joint in the axial direction.

9. The ignition system as claimed in claim 8 , wherein the joint fitting section is cylindrical and includes:
an inner peripheral step inclining radially outside as an inner periphery goes on to a base end side in the axial direction; and
a base end inner peripheral surface extending from an end of the inner peripheral step to a base end side in the axial direction,
wherein a cavity is formed at least between either the inner peripheral step or the base end inner peripheral surface and the sealing section.

10. The ignition system as claimed in claim 7 , wherein the high tension tower includes a retainer to prevent removal of the coupling unit, the retainer projecting radially outside;
wherein the coupling unit includes a recess to accommodate the retainer,
wherein the neck portion is located at a position overlapping with the recess in the radial direction.

11. The ignition system as claimed in claim 7 , wherein the coupling section includes a convex portion on its outer peripheral surface, the convex portion extending radially outside at a position adjacent to a tip side relative to the neck portion in the axial direction.

12. The ignition system as claimed in claim 7 , wherein the neck portion has a prescribed length in the axial direction.

13. The ignition system as claimed in claim 7 , wherein the coupling unit includes the minimum diameter at the neck portion.

Assignees

• Denso Corp

Inventors

• Akimoto Katsunori

Classifications

• H01F27/04

  Leading of conductors or axles through casings, e.g. for tap-changing arrangements · CPC title

• F02P2017/121

  by measuring spark voltage · CPC title

• H01F38/12 Primary

  Ignition, e.g. for IC engines · CPC title

• F02P3/0442

  using digital techniques (F02P3/0456, F02P3/053, F02P3/0554, F02P3/0558 take precedence) · CPC title

• F02P7/067

  Electromagnetic pick-up devices {, e.g. providing induced current in a coil} · CPC title