Corona ignition device having a hollow coil body

Abstract

This disclosure relates to a corona ignition device having a coil, which has an elongate coil body and a coil winding wound onto the coil body, an ignition electrode connected to the coil, and an insulator, inside which the ignition electrode is situated. According to the present disclosure, the coil body has a hollow section.

Claims

1. A corona ignition device, comprising: a coil comprising an elongate coil body and a coil winding wound onto the coil body; an ignition electrode connected to the coil; and an insulator, inside which the ignition electrode is situated; wherein the coil body has a hollow section.

2. The corona ignition device according to claim 1, wherein the hollow section of the coil body is formed by a tube or sleeve.

3. The corona ignition device according to claim 1, wherein the coil body includes two or more parts.

4. The corona ignition device according to claim 1, wherein the coil body is thinner at an end facing the ignition electrode than at an end facing away from the ignition electrode, so that the coil winding has a smaller diameter at the end facing the ignition electrode than at the end facing away from the ignition electrode.

5. The corona ignition device according to claim 1, wherein the coil body is closed at both ends.

6. The corona ignition device according to claim 1, wherein the coil body has at an end facing the ignition electrode a solid section, which is covered by the coil winding.

7. The corona ignition device according to claim 6, wherein the solid section has one or more grooves extending in the longitudinal direction of the coil body.

8. The corona ignition device according to claim 7, wherein the groove or the grooves are gas-filled.

9. The corona ignition device according to claim 1, wherein the coil winding is a single-layered coil winding.

10. The corona ignition device according to claim 1, wherein the coil is surrounded by a tubular housing.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The above-mentioned aspects of exemplary embodiments will become more apparent and will be better understood by reference to the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

(2) FIG. 1 shows a partially cut-away view of a corona ignition device;

(3) FIG. 2 shows an exemplary embodiment of the coil body of the corona ignition device;

(4) FIG. 3 shows a further exemplary embodiment of the coil body of the corona ignition device; and

(5) FIG. 4 shows a further exemplary embodiment of the coil body of the corona ignition device.

DESCRIPTION

(6) The embodiments described below are not intended to be exhaustive or to limit the invention to the precise forms disclosed in the following detailed description. Rather, the embodiments are chosen and described so that others skilled in the art may appreciate and understand the principles and practices of this disclosure.

(7) The corona ignition device shown schematically in FIG. 1 has a coil having a preferably single-layered coil winding 1 and a coil body 2, which is series-connected to an ignition electrode 3, which can have a plurality of ignition tips. The ignition electrode 3 is situated inside an insulator 4, which is held in a housing 5 and can project out of said housing. In the embodiment shown, a rear part 6 of the housing 5 surrounds the coil, while a front part of the housing 5 surrounds a section of the insulator 4. The corona ignition device has at its rear end an electrical connection in the form of a plug 7. The housing 5 is filled with an electrically insulating gas, which may be under pressure, e.g., of 300 kPa or more.

(8) The coil body 2 is thinner at its end facing the ignition electrode 3 than at its end facing away from the ignition electrode 3, so that the coil winding 1 has a smaller diameter at its end facing the ignition electrode 4 than at its end facing away from the ignition electrode 4.

(9) The elongate coil body 2 on which the coil winding 1 is wound has a hollow section that contains dry air or any other electrically insulating gas, e.g., nitrogen. The empty cavity 8 of said section is indicated in FIG. 1. The hollow section is surrounded at least by a part of the coil winding. The fact that at least part of the coil body 2 is hollow means that the weight of said coil body can be reduced to the extent that the resonant frequencies of the coil body 2 lie outside the excitation range of internal combustion engines customary in vehicles and/or that the occurring radial deflections of the coil body 2 are low. Vibrations of the coil body 2, which exert considerable stress on connection points of the coil, can thus be avoided and the service life of the corona ignition device can be prolonged.

(10) In the embodiment shown in FIG. 2, only a thicker section 2a of the coil body 2 is hollow. A thinner, cylindrical section 2b, which is solid, adjoins the thicker section 2a, which is tubular or sleeve-shaped. The thicker section 2a tapers towards the thinner section 2b. The hollow, thicker section 2a bears only some of the turns of the coil winding 1, for example between one quarter and one half of the total turns of the coil winding 1. The thicker, hollow section 2a is closed with a cover 9 at its end facing away from the ignition electrode 3. The cover 9 has a cylindrical continuation, which engages in the coil body 2, and a flange, which bears against the end of the coil body 2.

(11) FIG. 3 shows a further exemplary embodiment of a coil body 2, which differs from the exemplary embodiment of FIG. 2 only in that the thinner, solid section 2b of the coil body 2 has on its outside one or more grooves 10 running in the longitudinal direction. At least one of said grooves 10 can be empty, that is, filled with gas. The grooves 10 thus additionally reduce the mass of the coil body 2 and, like the thicker, hollow section 2a, help to ensure that the resonant frequency of the coil body 2 lies outside the excitation range of common internal combustion engines. In addition, the grooves 10 make it possible to save on materials during the injection-moulding process.

(12) A further embodiment of a coil body 2 is shown in FIG. 4. In this embodiment, both the thicker section 2a and the thinner section 2b are hollow.

(13) The coil body 2 can be composed of part-bodies. For example, the sections 2a and 2b can be produced separately and connected in a materially cohesive or form-fitting manner.

(14) While exemplary embodiments have been disclosed hereinabove, the present invention is not limited to the disclosed embodiments. Instead, this application is intended to cover any variations, uses, or adaptations of this disclosure using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.

LIST OF REFERENCE SYMBOLS

(15) 1 Coil winding 2 Coil body 2a Section of the coil body 2b Section of the coil body 3 Ignition electrode 4 Insulator 5 Housing 6 Housing section 7 Plug 8 Cavity 9 Cover 10 Groove