Spark plug
AssigneeCaterpillar Energy Solutions GmbH
InventorsOlaf Berger, Friedrich Schaefer
Life of this patent
Estimating the term…
Abstract
A spark plug may include a shell surrounding a lower part of an insulator. The shell may be provided with a tool engaging portion, a seal face configured to contact a corresponding seal of a cylinder head of an internal combustion engine, a cylinder engaging threaded portion having a thread diameter (D) configured to screw the spark plug in a threaded bore of the cylinder head, and an intermediate portion extending between the shoulder and the cylinder engaging threaded portion. The intermediate portion may have a length (L1), wherein: 0.20<=L1/D<=0.80 and L1 is the length and D is the thread diameter.
Claims20
A spark plug, comprising:
- a connector;
- a center electrode connected to the connector;
- an insulator surrounding the center electrode;
- a shell surrounding a lower part of the insulator, the shell being provided with a tool engaging portion, a seal face configured to contact a corresponding seal of a cylinder head of an internal combustion engine, a cylinder engaging threaded portion having a thread diameter (D) configured to screw the spark plug in a threaded bore of the cylinder head, and an intermediate portion extending between the seal face and the cylinder engaging threaded portion, wherein the intermediate portion has a length (L1), wherein:
- 0.20<=L1/D<=0.80 and L1 is the length and D is the thread diameter;
- and
- at least one ground electrode disposed at an end of the cylinder engaging threaded portion.
A cylinder head of an internal combustion engine, comprising:
- at least one bore configured to receive an associated spark plug;
- wherein each bore has a first bore part provided with an inner wall and a first inner diameter (d1) and a first length (L1), and a second bore part provided with an internal thread having a thread diameter (D), wherein:
- 0.20<=L1/D<=0.80 and L1 is the first length and D is the thread diameter.
A spark plug bushing configured to be inserted in a cylinder head of an internal combustion engine, the spark plug bushing comprising:
- a bushing body having an external thread configured to screw the spark plug bushing in a receiving bore of the cylinder head, and a stepped bore having a large diameter portion and a small diameter portion, wherein a seat shoulder for contacting a corresponding seal face of a spark plug is formed between the large diameter portion and the small diameter portion;
- the small diameter portion having a first bore part with a first diameter (d1) and a first length (L1) and a second bore part provided with an internal thread having a thread diameter (D) and a second length (L2), wherein:
- 0.20<=L1/D<=0.80 and L1 is the first length and D is the thread diameter.
Dependencies are inferred from the claim text.