Ignition device for an extraneously igniting combustion piston engine

Abstract

An ignition device for an extraneously igniting combustion piston engine with an ignition chamber located between a cylinder head and a piston, wherein the cylinder head has an end surface which defines the ignition chamber and which is at least partially formed as a cylinder head electrode, and wherein an ignition chamber electrode is disposed within the ignition chamber and forms an ignition gap with the cylinder head electrode.

Claims

1. Ignition device for an extraneously igniting combustion piston engine with an ignition chamber located between a cylinder head and a piston, wherein a cylinder head electrode is formed by at least a portion of the cylinder head, and wherein an ignition chamber electrode is disposed within the ignition chamber and forms an ignition gap with the cylinder head electrode; and wherein the ignition gap extends at least one quarter of the extent of the ignition chamber along a movement axis of the piston, wherein the ignition chamber electrode is connected to a high voltage source by a supply line disposed on the cylinder head and electrically isolated from the cylinder head and wherein the cylinder head electrode is in electrical communication with the cylinder head.

2. Ignition device as claimed in claim 1, wherein the end surface of the cylinder head, in the region of the cylinder head electrode, has a protrusion into the ignition chamber.

3. Ignition device as claimed in claim 1, wherein the ignition chamber electrode is immobile and disposed closer to the top dead center of the piston than it is to the cylinder head electrode.

4. Ignition device as claimed in claim 1, wherein the ignition chamber electrode is immobile and disposed at a bounding surface of the ignition chamber, which is defined by the top dead center of the piston.

5. Ignition device as claimed in claim 1, wherein the ignition chamber electrode is formed to match an upper piston end surface.

6. Ignition device for an extraneously igniting combustion piston engine with an ignition chamber located between a cylinder head and a piston, wherein a cylinder head electrode is formed by at least a portion of the cylinder head, and wherein an ignition chamber electrode is disposed within the ignition chamber and forms an ignition gap with the cylinder head electrode; and wherein the ignition gap extends at least one quarter of the extent of the ignition chamber along a movement axis of the piston, wherein the ignition chamber electrode is formed as a fluid-permeable and gas-permeable grid.

7. Ignition device as claimed in claim 6, wherein the ignition chamber electrode has at least one aperture for an inlet valve and/or an outlet valve of the internal combustion engine.

8. Ignition device as claimed in claim 1, wherein the ignition chamber electrode is formed to match the cylinder head electrode, wherein the ignition chamber electrode has a surface parallel and aligned with a surface of the cylinder head electrode, whereby each point on the surface of the ignition chamber electrode oriented toward the ignition gap is at substantially the same distance to a corresponding point of the cylinder head electrode.

9. Ignition device as claimed in claim 1, wherein the supply line of the ignition chamber electrode extends through the cylinder head electrode.

10. Ignition device for an extraneously igniting combustion piston engine with an ignition chamber located between a cylinder head and a piston, wherein a cylinder head electrode is formed by at least a portion of the cylinder head, and wherein an ignition chamber electrode is disposed within the ignition chamber and forms an ignition gap with the cylinder head electrode; and wherein the ignition gap extends at least one quarter of the extent of the ignition chamber along a movement axis of the piston, wherein a supply line of the ignition chamber electrode is disposed at a connecting point of the cylinder head and cylinder body.

11. A combustion piston engine having an ignition device as claimed in claim 1.

12. Ignition device as claimed in claim 1, wherein the movement axis is defined by a direction of mobility of the piston relative to the cylinder head.

13. Ignition device as claimed in claim 1, wherein the cylinder head electrode is integral with and stationary relative to the cylinder head.

14. Ignition device for an extraneously igniting combustion piston engine with an ignition chamber located between a cylinder head and a piston, wherein a cylinder head electrode is formed by at least a portion of the cylinder head, and wherein an ignition chamber electrode is disposed within the ignition chamber and forms an ignition gap with the cylinder head electrode; and wherein the ignition gap extends at least one quarter of the extent of the ignition chamber along a movement axis of the piston, wherein the ignition chamber electrode has a non-planar surface formed to match an upper piston end surface, which is non-planar.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Advantageous embodiments of the invention will become clear from the dependent claims, advantageous embodiments will become clear from the following descriptions in conjunction with the figures. The figures show in detail:

(2) FIG. 1 is a schematic cross-sectional view of an ignition device with an ignition chamber electrode, formed to match the upper piston end surface, in accordance with a first embodiment of the invention; and

(3) FIG. 2 is a schematic cross-sectional view of an ignition device with a supply line extending on the cylinder head electrode to the ignition chamber electrode, in accordance with a second embodiment of the invention.

DETAILED DESCRIPTION

(4) In FIGS. 1 and 2, different exemplified embodiments of an ignition device 1 for an extraneously igniting combustion piston engine 2 is illustrated. In both exemplified embodiments, the piston 4 is shown at the top dead-centre 6 of its reciprocating movement along a movement axis L of the piston 4. A dead space remaining beyond the movement range of the piston 4 (along the axis L to an end face 8 of a cylinder head 10) is here designated as ignition chamber 12. The bounding of the ignition chamber 12 is shown in both exemplified embodiments by a double dashed chain line. In both exemplified embodiments, the piston 4 is guided with its outer surface exclusively on a cylinder body 14, not on the cylinder head 10.

(5) FIG. 1 shows a first exemplified embodiment of the ignition device 1, in which the ignition chamber electrode 16 is formed to match an upper piston end surface 18 and is disposed in the proximity of a bounding surface 19 defined by the top dead-centre 6 of the piston 4.

(6) It is clear from the cross-sectional illustration A-A that the ignition chamber electrode 16 is formed as a grid 20 and is fixed in the ignition chamber at two opposing sides on a respective isolating arm 22 and 24 respectively. The isolating arms 22 and 24 are formed as projections of a surrounding isolating ring 26 which is inserted at a connecting point 27 of the cylinder head 10 and cylinder body 14. The electric supply line 28 extends through the isolating arm 22 and the corresponding side of the isolating ring 26 from a voltage source 30 to the ignition chamber electrode 16. In this exemplified embodiment, the ignition chamber electrode is provided as a cathode, which is illustrated by the + which has been drawn in on the voltage surface 30.

(7) The anode of the ignition device 1 is formed by a cylinder head electrode 32 which forms a part of the end surface 8 of the cylinder head 10. In the illustrated exemplified embodiment, the part formed as the cylinder head electrode 32 is formed to match both the corresponding part of the piston end surface 18 and also of the ignition chamber electrode 16. The cylinder head 10 formed from a conductive material is connected to the negative pole of the voltage source 30 by means of an electric supply line 34.

(8) FIG. 1 shows the arrow 36 as an example for the large number of possible ignition gaps (with substantially the same distance x) between the cylinder head electrode 32 and the ignition chamber electrode 16.

(9) An inlet valve 38 and an outlet valve 40 of the combustion piston engine 20 is electrically decoupled with respect to the cylinder head 10 by valve isolating rings 42 and 44.

(10) By applying sufficient ignition voltage by means of the voltage source 30, an ignition spark is formed along the ignition gap 36 between the part, which is formed as a cylinder head electrode 32, of the end surface 8 of the cylinder head 10 and the grid 20 of the ignition chamber electrode 16, which ignition spark corresponds in its length at least to the distance between the electrodes with respect to the axis L and which therefore permits simultaneous initiation of the ignition in a clearly larger part of the ignition chamber 12 than would be the case e.g. in the case of a conventional spark plug. Nevertheless, in the illustrated embodiment, electrical isolation is possibly merely with non-moved isolating components (22, 24, 26, 42 and 44). For the sake of simplicity, isolation of the supply lines 28 and 34 outside the cylinder is not shown.

(11) In the illustrated embodiment each point of the ignition chamber electrode 16 oriented towards the ignition gap 36 is at substantially the same distance x to a corresponding point of the cylinder head electrode 32. In this way the actual course of the ignition gap 36 (which is shown by way of example by arrow 36) can be determined by random factors such as e.g. a locally higher proportion of petrol in the petrol-air mixture and/or tolerances of a material formation on one or both electrodes.

(12) A dashed line in FIG. 1 shows an alternative arrangement of the ignition chamber electrode 16 B. The ignition chamber electrode 16 B differs from the ignition chamber electrode 16 substantially in that it is disposed closer to the cylinder head electrode 32, which can be necessary e.g. in modern motor vehicle engines in order to achieve an efficient construction space arrangement of the engine. In order also in such a case to avoid the stroke of the valves 42 and 44 colliding with the electrode 16 B formed analogously to the electrode 16, apertures 46.1 and 46.2 are formed as the corresponding points, wherein the illustration in cross-section B-B is to be understood as not being to scale.

(13) The embodiment of the ignition device 1 illustrated in FIG. 2 differs from that in FIG. 1 substantially in that the supply line 128 of the ignition chamber electrode 106 extends through the cylinder head electrode 132 and in that the ignition chamber electrode 106 is not formed to match either the piston end surface 118 or the end surface 108 of the cylinder head 10. A further difference is the design of the end surface 108 with a protrusion 150 which extends into the ignition chamber 12. Further features are provided analogously to the exemplified embodiment in accordance with FIG. 1 and are thus provided with the same reference numerals as in FIG. 1.

(14) An isolating arm 154 is guided in a flush manner through the aperture 152 in the cylinder head 10 and extends along the axis L into the ignition chamber 12, through about of the extent of the ignition chamber 12. At an ignition chamber-side end of the isolating arm 154, the ignition chamber electrode 106 protrudes out of this arm and, together with the protrusion 150 of the cylinder head electrode 132, forms a clearly defined ignition gap which is shown by the arrow 136. In contrast to the exemplified embodiment in accordance with FIG. 1, in this case the ignition gap 136 is formed by the minimal distance between the protrusion 150 and the tip of the ignition chamber electrode 106.

(15) By guiding both electric supply lines 128 and 34 on the upper side of the cylinder head 10, a relatively simple isolationrequiring little construction spaceof the supply lines 128 and 34 with respect to the surrounding area can be achieved. The cylinder body 14 is electrically decoupled from the cylinder head 10 by a simple isolating ring 26.

(16) A suitable ceramic material or another material which is known per se to the person skilled in the art can be used as the material for the electrically isolating elements 22, 24, 26, 42, 44 and 128 in the described exemplified embodiments.