An engine cam cover with integrated wiring provides quick-connect capability for electrical components in a manner that simultaneously establishes electrical interconnection and mechanical fastening. The cover comprises a shell with inner and outer layers defining a plurality of sockets with respective passages for receiving respective electrical components. A wire bundle has a plurality of wires extending from a connector end at a periphery of the shell to a terminal end disposed within a space between the layers. A plurality of retainers are disposed in respective passages, each having at least one helical track for rotationally receiving a connector pin extending radially from a respective electrical component. A plurality of metal cups installed at an end of each helical track are connected to respective wires at a respective terminal end. Each socket is configured to provide a latch to hold each respective connector pin at the respective track end.

A spark plug for an internal combustion engine is provided which includes a housing, a porcelain insulator, a center electrode, and an annular ground electrode. The housing has a small-diameter portion which has a smaller inner diameter and defines a front end thereof. The ground electrode is secured to a front end surface of the small-diameter portion and forms a spark gap between itself and an outer periphery of the center electrode. A pocket is formed between the inner periphery of the housing and a portion of the porcelain insulator which is located closer to a front end of the porcelain insulator than the mounting shoulder is. An air vent extends from outside the ground electrode in a radial direction of the spark plug to the pocket to establish communication between the pocket and the combustion chamber of the internal combustion engine.

A spark plug 5 for an internal combustion engine includes a center electrode 1, an insulator 2, and a housing 3. The insulator 2 includes a distal end side exposed part and an insulator enlarged diameter part 21. The housing 3 includes a lateral electrode 32, an engaging part 33, and a crimping portion 35. A buffer member 4 that restrains the distal end side exposed part 20 by pressing a part of the distal end side exposed part 20 toward the center and a part of the inner peripheral surface of the lateral electrode 32 in a radial direction at a distal end side of the engaging part 33 is disposed at a base end side of the gas pocket 230.

A spark plug 5 for an internal combustion engine includes a center electrode 1, an insulator 2, and a housing 3. The insulator 2 includes a distal end side exposed part and an insulator enlarged diameter part 21. The housing 3 includes a lateral electrode 32, an engaging part 33, and a crimping portion 35. A buffer member 4 that restrains the distal end side exposed part 20 by pressing a part of the distal end side exposed part 20 toward the center and a part of the inner peripheral surface of the lateral electrode 32 in a radial direction at a distal end side of the engaging part 33 is disposed at a base end side of the gas pocket 230.

To provide a spark plug that can reduce power loss and prevent erosion of a tip end part of a central electrode, even in a configuration such that a discharge current and an electromagnetic wave are emitted from a terminal fitting part of the spark plug, and a plasma generation device using the spark plug. The spark plug is provided with a central electrode 2 including a terminal fitting part 2A and an electrode main body 2B electrically connected to the terminal fitting part 2A, an insulator 3 formed with an axial hole 30, which the central electrode 2 is fitted into, a main fitting 4 that surrounds the insulator 3, and a ground electrode 5 that extends from an end surface of the main fitting 4 and is adapted to form a discharge gap that causes a spark discharge between the central electrode 2 and the electrode main body 2B. The electrode main body 2B is constituted of a front electrode 25 including an electrode tip part 25a for causing the spark discharge with the ground electrode 5, a front dielectric cylinder 24 in a tube-like shape that covers the electrode tip part 25a, and a coupling conductive cylinder 23 in a tube-like shape that joins the front dielectric cylinder 24 and the terminal fitting part 2A.

A spark plug for an internal combustion engine is provided which includes a housing, a porcelain insulator, a center electrode, and an annular ground electrode. The housing has a small-diameter portion which has a smaller inner diameter and defines a front end thereof. The ground electrode is secured to a front end surface of the small-diameter portion and forms a spark gap between itself and an outer periphery of the center electrode. A pocket is formed between the inner periphery of the housing and a portion of the porcelain insulator which is located closer to a front end of the porcelain insulator than the mounting shoulder is. An air vent extends from outside the ground electrode in a radial direction of the spark plug to the pocket to establish communication between the pocket and the combustion chamber of the internal combustion engine.

A spark plug that satisfies the relation 2.8(A+B)/M, where A is the sum of a length A1 of contact between a sheet packing and a metallic shell of a spark plug in one half section and a length A2 of contact between the sheet packing and the insulator in the one half section, and B is the sum of a length B1 of contact between the sheet packing and the metallic shell in the other half section and a length B2 of contact between the sheet packing and the insulator in the other half section. M is the difference obtained by subtracting the inner diameter D of a ledge from the inner diameter C of a middle hole portion.

In an internal combustion engine ignition coil apparatus, a high-voltage supplying portion has: a protector that is bonded to an ignition coil main body, an electrical conductor, and a resistor that is connected in series between the ignition coil main body and the electrical conductor, and that reduces conductive noise. An electromagnetic wave absorber that shields radiated noise that is generated in the high-voltage supplying portion is mounted to an engine block so as to surround the protector and the resistor. An end surface of the resistor near the ignition coil main body is disposed so as to be aligned with an end surface of the electromagnetic wave absorber near the ignition coil main body.