Method and device for introducing microwave energy into a combustion chamber of an internal combustion engine

Abstract

A method for introducing microwave energy into a combustion chamber of an internal combustion engine in which the microwaves reach a combustion chamber through a microwave window, wherein the microwaves are run about a circumference of the combustion chamber and radially coupled into the combustion chamber after passing through the microwave window. Accordingly a device for introducing microwave energy into the combustion chamber of a reciprocating piston internal combustion engine with at least one cylinder with a cylinder head and a combustion chamber in the cylinder includes at least one circumferential annular hollow conductor cavity extending about the combustion chamber and including at least one feed for the microwave and at least one outlet opening for the microwave arranged between the annular hollow conductor cavity and the combustion chamber. An internal combustion engine includes the features of the device.

Claims

1. A method for injecting microwave energy into a combustion chamber of a reciprocating piston internal combustion engine including at least one cylinder including a cylinder head, the method comprising the steps: passing the microwaves through a microwave window of the internal combustion engine, wherein the microwave window seals the combustion chamber relative to an external microwave feed outside the cylinder head, and wherein the microwave window is made from a solid microwave permeable material; running the microwaves about a circumference of a combustion chamber through an annular hollow conductor cavity which is configured as a channel that is arranged in the cylinder head and that extends about the combustion chamber after passing the microwaves through the microwave window; and radially injecting the microwaves into the combustion chamber after running the microwaves about the circumference of the combustion chamber.

2. The method according to claim 1, wherein the microwaves are injected into the combustion chamber through at least one annular hollow conductor cavity including a bar that envelops the combustion chamber and forms a wall of the at least one annular hollow conductor cavity towards the combustion chamber and including at least one outlet opening oriented towards the combustion chamber.

3. The method according to claim 2, wherein the microwaves are injected into the combustion chamber at an angle at an end of the at least one annular hollow conductor cavity.

4. The method according to claim 2, wherein the microwaves are injected from the at least one annular hollow conductor cavity through a gap circumferentially extending between the at least one annular hollow conductor cavity and the combustion chamber wall, or through a gap circumferentially extending between the at least one annular hollow conductor cavity and the combustion chamber wall and increasing in size with a length of a path of the microwave in the at least one annular hollow conductor cavity, or through a plurality of gaps arranged between the at least one annular hollow conductor cavity and the combustion chamber wall perpendicular to a propagation direction of the microwave and increasing in size with a length of a path of the microwave in the at least one annular hollow conductor cavity, or through a combination thereof.

5. The method according to claim 1, wherein the microwaves are injected with a frequency of 25 GHz to 90 GHz.

6. The method according to claim 1, wherein the microwaves are injected in impulse packets, and wherein the impulse packets are maintained after an ignition of a fuel air mix has already been provided.

7. The method according to claim 1, wherein the microwaves are injected as a function of an angle of a crank shaft.

8. A device for injecting microwave energy into a combustion chamber of an internal combustion engine, comprising: at least one cylinder with a cylinder head and a combustion chamber, wherein microwaves are injected through a microwave window into the combustion chamber, wherein the cylinder head includes at least one circumferential annular hollow conductor cavity circumferentially extending about the combustion chamber and including at least one feed for the microwaves and at least one outlet opening for the microwaves arranged between the at least one circumferential annular hollow conductor cavity and the combustion chamber.

9. The device according to claim 8, wherein a wall oriented at an angle relative to the at least one circumferential annular hollow conductor cavity and an outlet opening oriented in a direction towards the combustion chamber are arranged at an end of the at least one circumferential annular hollow conductor cavity.

10. The device according to claim 8, wherein a gap is provided circumferentially extending between the at least one circumferential annular hollow conductor cavity and the combustion chamber wall, or a gap is provided circumferentially extending between the at least one circumferential annular hollow conductor cavity and the combustion chamber wall and increasing in size with a length of a path of the microwaves in the at least one circumferential annular hollow conductor cavity, or a plurality of gaps is provided between the at least one circumferential annular hollow conductor cavity and the combustion chamber wall perpendicular to a propagation direction of the microwaves and advantageously increasing in size with a length of a path of the microwaves in the at least one circumferential annular hollow conductor cavity, or a combination thereof is provided.

11. The device according to claim 8, wherein the at least one circumferential annular hollow conductor cavity is configured as a channel extending about the combustion chamber, wherein the channel includes a ring that is insertable onto the channel and includes points protruding into the combustion chamber.

12. The device according to claim 8, wherein an additional annular hollow conductor cavity is provided adjacent to the at least one circumferential annular hollow conductor cavity, and wherein the additional annular hollow conductor cavity includes outlet openings that are offset relative to outlet openings of the at least one circumferential annular hollow conductor cavity.

13. The device according to claim 12, wherein the additional annular hollow conductor cavity is arranged in an annular component which is arranged adjacent to the at least one circumferential annular hollow conductor cavity with the additional annular hollow conductor cavity of the annular component arranged in an opposite direction relative to the at least one circumferential annular hollow conductor cavity wherein an annular flat ring is arranged between the annular component and the at least one circumferential annular hollow conductor cavity, wherein the annular flat ring is provided with points protruding into the combustion chamber, and wherein the annular flat ring forms a divider wall between the additional annular hollow conductor cavity and the at least one circumferential annular hollow conductor cavity, and wherein the annular flat ring simultaneously forms a wall for the additional annular hollow conductor cavity and for the at least one circumferential annular hollow conductor cavity.

14. An internal combustion engine, comprising the device for injecting microwave energy according to claim 8.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention is subsequently can be described in more detail with reference to schematic drawing figures. Additional features of the invention can be derived from the subsequent description in combination with the patent claims and the appended drawing figures, wherein:

(2) FIG. 1A illustrates a cylinder head with ring injection with a constant slot in a perspective view;

(3) FIG. 1B illustrates the cylinder head of FIG. 1A in a in a top view;

(4) FIG. 1C illustrates the cylinder head of FIG. 1A in a sectional view:

(5) FIG. 2A illustrates a cylinder head with ring injection with an annular gap into the combustion chamber which gap increases in size over a path in a perspective view;

(6) FIG. 2B illustrates the cylinder head of FIG. 2A in a top view;

(7) FIG. 2C illustrates the cylinder head of FIG. 2A in a sectional view;

(8) FIG. 3A illustrates a cylinder head with ring injection with a plurality of openings into the combustion chamber in a perspective view;

(9) FIG. 3B illustrates the cylinder head of FIG. 3A in a top view;

(10) FIG. 3C illustrates the cylinder head of FIG. 3A in a first sectional view;

(11) FIG. 3D illustrates the cylinder head of FIG. 3A in a second sectional view offset by 90 relative to the first sectional view, wherein the sectional views also illustrate a detail of the internal combustion engine;

(12) FIG. 4A illustrates a counter piece for a ring injection according to FIG. 3 in a perspective view;

(13) FIG. 4B illustrates the counterpiece according to FIG. 4A in a top view;

(14) FIG. 4C illustrates the counter piece according to FIG. 4A in a sectional view along the line A-A:

(15) FIG. 4D illustrates the counter piece according to FIG. 4A in a sectional view along the line B-B;

(16) FIG. 5A illustrates a cylinder head according FIG. 2 in which an annular hollow conductor cavity with an enlarging opening is formed by an inserted cover ring in a perspective view,

(17) FIG. 5B illustrates a cylinder head according FIG. 2 in which an annular hollow conductor cavity with an enlarging opening is formed by an inserted cover ring in top view;

(18) FIG. 5C illustrates a cylinder head according FIG. 2 in which an annular hollow conductor cavity with an enlarging opening is formed by an inserted cover ring in a sectional view;

(19) FIG. 6A illustrates a cover ring for forming an annular hollow conductor cavity with additional points in a perspective view;

(20) FIG. 6B illustrates the cover ring of FIG. 6A in a top view;

(21) FIG. 7A illustrates cylinder head according to FIGS. 3 and 4 in assembled condition in a perspective view;

(22) FIG. 7B illustrates the cylinder head according to FIGS. 3 and 4 in assembled condition in a top view;

(23) FIG. 7C illustrates the cylinder head according to FIGS. 3 and 4 in assembled condition in a sectional view along the line A-A;

(24) FIG. 7D illustrates the cylinder head according to FIGS. 3 and 4 in assembled condition in a sectional view along the line B-B;

(25) FIG. 8 illustrates a cross section through a detail of an internal combustion engine with a cylinder with a ring injection in the embodiment according to FIG. 3.

DETAILED DESCRIPTION OF THE INVENTION

(26) In the subsequently described figures the invention is illustrated in an exemplary manner based on various embodiments. Identical or like elements in the individual figures are provided with identical reference numerals.

(27) FIG. 1A illustrates a perspective view of a cylinder head 1 made from metal that includes a cambered combustion chamber 2. In this embodiment a plurality of bore holes 3 leads into the combustion chamber 2, wherein the bore holes are arranged in a center of the combustion chamber 2 and a fuel air mixture can be introduced through the bore holes. The exhaust gases are let out in a manner that is typical for engines of this type. It is appreciated that an inlet valve or an outlet valve can be arranged in the cylinder head 1 in a customary manner. This embodiment includes an additional bore hole 4 into which an additional spark plug can be inserted if necessary. When sufficient microwave energy is introduced and a space ignition is accordingly achieved in the combustion chamber 2, this bore hole can also be omitted. The cylinder head 1 includes an opening 5 at its circumference in which or in front of which a microwave window 6 is arranged that is illustrated in an exemplary manner in FIG. 7 in order to separate the combustion chamber 2 from the space arranged outside of the cylinder so that no gases can move through this path back into a microwave feed illustrated in FIG. 7. The opening 5 is an end of a cavity 8 which leads into an annular cavity 9 which extends about the combustion chamber 2. As apparent from the figures the annular cavity 9 is configured as a channel in the cylinder head 1 wherein the channel becomes an annular hollow conductor cavity by using a ring 17, 17 which will be illustrated infra with reference to FIGS. 5 and 6. Therefore this cavity is designated in the open illustration as an annular cavity 9 and in the closed illustration as annular hollow conductor cavity 9. A bar 10 enveloping the combustion chamber 2 forms the wall of the annular conductor 9 towards the combustion chamber 2. The bar 10 includes an opening 11 at an end of the hollow conductor cavity 9 wherein the opening connects the annual cavity 9 with the combustion chamber 2. Additionally the face wall 12 arranged at an end of the annular cavity 9 is configured at a slant angle so that the microwaves extending in the annular cavity 9 impact the face wall 12 at an angle so that they are not reflected back by the annular cavity 9 or only reflected back to a small extent. Instead the microwave running through the annular cavity 9 can exit through the opening 11 into the combustion chamber. In the embodiment illustrated in FIG. 1 the wall forming bar 10 has a continuously constant height which is lower than the circumferential outer wall 13 about the channel shaped annular cavity 9. As evident in particular from FIG. 1C the annular cavity 9 is arranged in a larger recess 14 in the cylinder head 1 so that it forms a circumferential shoulder 15 which also extends into a portion 15 which extends between the face wall 12 and a deflection wall 16 that deflects the microwaves after an entry into the annular cavity 9. In order to form an annular hollow conductor cavity the annular cavity 9 is covered by a flat ring 17 (FIG. 5). This flat ring and an upper edge of the wall forming circumferential bar 10 creates a gap through which the microwaves can propagate into the combustion chamber 2 during its circumferential run through the annular hollow conductor cavity 9. This portion is designated in FIG. 1C with reference numeral 18.

(28) FIG. 2 corresponds to FIG. 1 with the difference that the wall forming bar 10 is continuous, this means at its end proximal to the face wall 12 there is no separate opening. Thus, the bar decreases in height from a beginning of the annular cavity 9 at the deflection wall 16 to and end at the face wall 12 continuously. Also here the annular hollow conductor cavity 9 is formed by a flat ring 17, 17 as illustrated in FIG. 5 or in FIG. 6.

(29) In the embodiment according to FIG. 3 a plurality of individual bars 19 with outlet openings 20 arranged there between is provided instead of a singular wall forming bar. In the embodiment the individual bars 19 have constant height and constant distance. The distance, however, can vary over the length of the annular cavity 9. In this embodiment no bore hole for an additional spark plug is illustrated. FIG. 1B illustrates the cavity 8 which leads into the annular cavity 9. Also here the annular hollow conductor cavity is formed by applying the ring 17 according to FIG. 5 or the ring 17 according to FIG. 6. In FIGS. 3C and 3D the elements illustrated in FIGS. 3A and 3B as far as they are visible are illustrated in cross section.

(30) FIG. 4 illustrates a cylinder head counter piece 1 which is essentially configured according to the cylinder head 1 in FIG. 3 with the difference that the opposite piece is configured as a ring with a pass through opening 21 for enlarging the combustion chamber 2 and the pass through of a piston of a reciprocating piston internal combustion engine that is not illustrated in this figure. The annular cavity is designated here in as 9. This cylinder head counter piece 1 can be attached at the cylinder head 1 according to FIG. 3 in opposite direction, this means so that the opposite bars 19 are oriented towards each other wherein in the recess 14 according to FIGS. 3C and 3D the ring 17 or 17 according to FIGS. 5 and 6 can be inserted as a divider. The respective ring 17 or 17 forms en annular follow conductor cavity in the cylinder head 1 and also in the cylinder head counter piece. The respective ring 17 or 17 contacts the shoulder 15 in the recess 14. This recess is missing in the cylinder head counter piece 1.

(31) FIG. 5 illustrates a cylinder head 1 according to FIG. 2 with a wall forming bar 10 whose height decreases over the length of the annular cavity 9 with an inserted flat ring 17 which forms an annular hollow conductor cavity 9.

(32) FIG. 6 illustrates a configuration of the ring 17 with ignition points 22 which are oriented in a direction towards a center point of the ring and which generate local field augmentations.

(33) FIG. 7 illustrates an assembly of a cylinder head 1 with a cylinder head counter piece 1 according to FIGS. 3 and 4 with individual bars 19 and a ring according to FIG. 5 for dividing the respective annular hollow conductor cavities 9, 9 in the cylinder head 1 or the cylinder head counter piece 1. At the cylinder head 1 and the cylinder head piece 1 respective microwave feeds 7 are illustrated which include a microwave window 6 in front of an entry into the opening 5 for the hollow cavity 8. In the embodiment the cylinder head 1 and the cylinder head counter piece 1 are arranged at one another so that the microwave feeds 7 are arranged exactly opposite to each other. It is certainly feasible to select another arrangement through rotation as a function of requirements for a respective application.

(34) FIG. 8 schematically illustrates a detail of a reciprocating piston, internal combustion engine 25 with a cylinder 23 in which a piston 24 is moveable with a cylinder head in which an annular cavity 9 with individual bars 19 according to FIG. 3 is arranged for microwave ring injection. This figure also illustrates the microwave feed 7 with microwave windows 6 illustrated in FIG. 7.

(35) As recited supra individual features in respective embodiments can be combined with other features of another embodiment when this is useful. As apparent from the FIGs the cylinder head 1 is a component that can be produced in a simple manner wherein the annular hollow conductor cavity 9 is formed by inserting a respective ring 17 or 17. The respective ring 17 or 17 is used as a divider wall for a cylinder head counter piece 1.

(36) The cylinder heads 1 are made from a typical material, typically metal, wherein the material can be selected according to the application. The boundary for the microwaves in the illustrated hollow conductor cavities is certainly made from metal, wherein additional measures can be taken in order to optimize conductivity, for example by surface coating with a highly electrically conductive material.