Abstract
A spark plug, including a central electrode, a first ground electrode, which is situated in a curved shape having a horizontal area and an essentially vertical area, and at least one second ground electrode, which is situated adjacent to the central electrode in such a way that a distance between the first ground electrode and the central electrode is less than a distance between the second ground electrode and the central electrode.
Claims
1. A method for generating sparks in a spark plug, comprising: attaching a first ground electrode and a second ground electrode to the spark plug; positioning the first ground electrode and the second ground electrode at a first distance and a second distance, respectively, from a central electrode, wherein the second distance is greater than the first distance; generating a spark during operation only between the first ground electrode and the central electrode; removing the first ground electrode from the spark plug; repositioning the second ground electrode to the first distance from the central electrode; and generating a spark during operation only between the second ground electrode and the central electrode.
2. The method of claim 1, wherein the second distance between the second ground electrode and the central electrode is such that no sparks are generated.
3. The method of claim 1, wherein the first ground electrode is situated over the central electrode in the bent-over state, so as to form a top ground electrode, or the first ground electrode is situated adjacent to the central electrode in the bent-oyer state, so as to form a laterally placed ground electrode.
4. The method of claim 1, wherein a length of the second ground electrode is less than a length of the first ground electrode.
5. The method of claim 1, wherein a noble metal area is provided on the first ground electrode and a noble metal area is provided on the second ground electrode, starting from a fastening area of the ground electrodes on the spark plug, and wherein the noble metal area of the first ground electrode is situated at a different position in the longitudinal direction of the first ground electrode than the noble metal area of the second ground electrode.
6. The method of claim 1, wherein the spark plug includes a third ground electrode and a fourth ground electrode.
7. The method of claim 1, wherein the plurality of ground electrodes is situated at an equal peripheral distance from one another along a periphery of the spark plug.
8. A method for using a spark plug in an internal combustion engine, the method comprising: attaching a first ground electrode and a second ground electrode to the spark plug; positioning the first ground electrode and the second ground electrode at a first distance and a second distance, respectively, from a central electrode, wherein the second distance is greater than the first distance such that during operation sparks are generated only between the first ground electrode and the central electrode; removing the first ground electrode from the spark plug after operation; repositioning the second ground electrode to the first distance from the central electrode such that during operation sparks are generated only between the second ground electrode and the central electrode.
9. The method of claim 8, wherein the spark plug includes a third ground electrode and a fourth ground electrode.
10. A method for using a spark plug in a heavy-duty motor vehicle, the method comprising: attaching a first ground electrode and a second ground electrode to the spark plug; positioning the first ground electrode and the second ground electrode at a first distance and a second distance, respectively, from a central electrode, wherein the second distance is greater than the first distance such that during operation sparks are generated only between the first ground electrode and the central electrode; removing the first ground electrode from the spark plug after operation; repositioning the second ground electrode to the first distance from the central electrode such that during operation sparks are generated only between the second ground electrode and the central electrode.
11. The method of claim 10, wherein the heavy-duty motor vehicle includes one of a truck, a construction machine, a bus, and a ship.
12. The method of claim 10, wherein the spark plug includes a third ground electrode and a fourth ground electrode.
13. The method of claim 12, further comprising: after operation, removing the second ground electrode from the spark plug; positioning the third ground electrode to the first distance from the central electrode such that during operation sparks are generated only between the third ground electrode and the central electrode.
14. The method of claim 13, further comprising: after operation, removing the third ground electrode from the spark plug; and positioning the fourth ground electrode to the first distance from the central electrode such that during operation sparks are generated only between the fourth ground electrode and the central electrode.
15. The method of claim 10, wherein the first ground electrode is removed by pinch force.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) FIG. 1 shows a schematic sectional view of a spark plug according to a first exemplary embodiment of the present invention.
(2) FIG. 2 shows a schematic top view of the spark plug shown in FIG. 1.
(3) FIG. 3 shows a partially cutaway view of a spark plug according to a second exemplary embodiment of the present invention.
(4) FIG. 4 shows a top view of a spark plug according to a second exemplary embodiment of the present invention.
(5) FIG. 5 shows a side view of a spark plug according to a third exemplary embodiment of the present invention.
(6) FIG. 6 shows a top view of a spark plug according to a third exemplary embodiment of the present invention.
(7) FIG. 7 shows a side view of a spark plug according to a fourth exemplary embodiment of the present invention.
(8) FIG. 8 shows a top view of a spark plug according to a fourth exemplary embodiment of the present invention.
(9) FIG. 9 shows a partially cutaway view of a spark plug according to a fifth exemplary embodiment of the present invention.
(10) FIG. 10 shows a top view of a spark plug according to a fifth exemplary embodiment of the present invention.
DETAILED DESCRIPTION
(11) A spark plug 1 according to a first exemplary embodiment of the present invention is described in greater detail hereafter with reference to FIGS. 1 and 2, FIG. 1 being a section along line I-I of FIG. 2.
(12) As shown in FIG. 1, spark plug 1 includes a central electrode 2, which is situated centrally in the spark plug and protrudes from a housing 7. Furthermore, spark plug 1 of the first exemplary embodiment includes four ground electrodes, namely a first ground electrode 3, a second ground electrode 4, a third ground electrode 5, and a fourth ground electrode 6 (cf. FIG. 2). The four ground electrodes are each situated along the periphery of the spark plug at an angle of 90 to an adjacent ground electrode. As shown in FIGS. 1 and 2, only first ground electrode 3 is active during operation in the illustrated state of spark plug 1. First ground electrode 3 is bent over by 90 into a curved shape for this purpose, so that it has a horizontal area 3a and a vertical area 3b, which are connected to one another via a curved area. First ground electrode 3 is situated in such a way with respect to central electrode 2 that a gap S1 is provided between them, and first ground electrode 3 is situated above central electrode 2 (cf. FIG. 2). First ground electrode 3 is thus a so-called top ground electrode, so that the ignition spark arises between first ground electrode 3 and central electrode 2 in gap S1. Three other ground electrodes 4, 5, 6 are situated vertically on the spark plug parallel to central electrode 2 corresponding to a longitudinal direction X-X of the spark plug. A distance of three other ground electrodes 4, 5, 6 is greater than distance S1 between first ground electrode 3 and central electrode 2. A distance between second ground electrode 4 and central electrode 2 is schematically shown in FIG. 2 and identified by S2. Because the four ground electrodes are connected to one another in the interior of housing 7, the greater distance of currently inactive ground electrodes 4, 5, 6 ensures that no sparks are generated between these ground electrodes and central electrode 2.
(13) When first ground electrode 3 is worn after a specific operating time, the spark plug is removed from the engine and first ground electrode 3 is pinched off or separated in another way in vertical area 3b, for example. Subsequently, second ground electrode 4 is bent over by 90 at its free end, so that it forms a new top ground electrode for central electrode 2. Because wear may also occur on central electrode 2 during operation, second ground electrode 4 may be bent over somewhat further in the axial direction in the direction of housing 7, so that an optimum distance is established between central electrode 2 and second ground electrode 4. A gauge, inter alia, may also be used for the bending-over procedure. When second ground electrode 4 is worn during further operation, it is also removed and instead third ground electrode 5 is bent over, and when third ground electrode 5 is worn after further operating hours, it is removed and fourth ground electrode 6 is bent over. Spark plug 1 according to the present invention of the first exemplary embodiment therefore has a service life that is approximately four times as long as that of a typical spark plug used until now having only one ground electrode. Because ground electrodes 4, 5, 6 which are held in reserve are each bent over immediately before their use, optimum orientation of the newly bent-over ground electrode may also be ensured, so that the spark plug is able to provide optimum power density.
(14) Ground electrodes 3, 4, 5, 6 and central electrode 2 may be provided in the form of noble metal pins or a base pin having an attached noble metal pin. For example, platinum, iridium, rhodium, ruthenium, or palladium, or arbitrary combinations and/or alloys of these noble metals may be used as the noble metal. The wear behavior may be improved further by the use of the noble metal. For example, an alloy having nickel as the main component may be used as the electrode base material. Alternatively, ground electrodes 3, 4, 5, 6 and central electrode 2 may also be equipped with laminas made of noble metal, the noble metal laminas being situated on the free end of central electrode 2 or the area of the ground electrodes which points directly toward central electrode 2 in the bent-over state. The noble metal laminas on the central electrode and the ground electrode in use are thus directly diametrically opposite one another.
(15) A spark plug 1 according to a second exemplary embodiment of the present invention is described in greater detail hereafter with reference to FIGS. 3 and 4. Identical or functionally identical parts are identified by identical reference numerals as in the first exemplary embodiment.
(16) Spark plug 1 of the second exemplary embodiment essentially corresponds to that of the first exemplary embodiment, with the exception of ground electrodes 4, 5, 6 which are held in reserve being pre-bent by a predetermined angle . Angle is approximately 20. As shown in the sectional view of FIG. 3 along line III-III of FIG. 4, reserve ground electrodes 4, 5, 6 are pre-bent inward in the direction of central electrode 2. The bending procedure after wear of one of the ground electrodes and the then used ground electrode may thus be executed more easily. Otherwise, this exemplary embodiment corresponds to the preceding exemplary embodiment, so that reference may be made to the description given there.
(17) A spark plug 1 according to a third exemplary embodiment of the present invention is described in greater detail hereafter with reference to FIGS. 5 and 6. Identical or functionally identical parts are again identified by identical reference numerals as in the preceding exemplary embodiment.
(18) In contrast to the preceding exemplary embodiments, spark plug 1 of the third exemplary embodiment only has a total of three ground electrodes, namely a first ground electrode 3, a second ground electrode 4, and a third ground electrode 5 (cf. FIG. 6). Furthermore, as shown in FIG. 5 in particular, a length of the three ground electrodes varies starting from the free end of the ground electrodes up to a fastening area, at which they are fastened on housing 7 of the spark plug. More precisely, first ground electrode 3 has a length L1, which is greater than a length L2 of second ground electrode 4, and length L2 of second ground electrode 4 being greater than a length L3 of third ground electrode 5. Length L1 of first ground electrode 3 is thus greater than length L2 of second ground electrode 4, which is in turn greater than length L3 of third ground electrode 5. Through this measure, it is possible that, because wear also occurs on central electrode 2 during operation so that protruding length L of central electrode 2 becomes shorter, second ground electrode 4, which is used after wear of first ground electrode 3, may be bent precisely over central electrode 2 due to its shorter length L2. Length L2 is shortened in relation to length L1 of first ground electrode 3 in such a way that the wear of central electrode 2 was also incorporated precisely, so that second ground electrode 4 lies optimally above central electrode 2. Accordingly, when second ground electrode 4 is also worn, third ground electrode 5 is bent over, central electrode 2 being worn still further, so that the shorter third ground electrode also optimally fits over central electrode 2. Otherwise, this exemplary embodiment corresponds to the preceding exemplary embodiment, so that reference may be made to the description given there.
(19) A spark plug 1 according to a fourth exemplary embodiment of the present invention is described in greater detail hereafter with reference to FIGS. 7 and 8. Identical or functionally identical parts are again identified by identical reference numerals as in the preceding exemplary embodiments.
(20) As shown in FIG. 8 in particular, the spark plug of the fourth exemplary embodiment includes a so-called laterally placed electrode instead of a top electrode. In the fourth exemplary embodiment, first ground electrode 3 and third ground electrode 5 are laterally placed simultaneously, so that sparking is possible between the central electrode and first and third ground electrodes 3, 5. Furthermore, as shown in FIG. 8, second ground electrode 4 and fourth ground electrode 5 are kept in reserve and protrude vertically from spark plug 1, and they are situated parallel to central electrode 2. When first ground electrode 3 and third ground electrode 5 are worn, second ground electrode 4 and fourth ground electrode 6 are bent over and replace the worn ground electrodes, so that the total service life of the spark plug may be lengthened, as described in the preceding exemplary embodiment. The laterally placed ground electrodes have the advantage that in particular the bending-over procedure may be performed more easily, because the free end of the ground electrodes may be gripped readily using a tool and the reshaping procedure may be performed. It is to be noted in this case that spark plug 1 according to the fourth exemplary embodiment may also be designed in such a way that only one of the ground electrodes is bent over and is used during operation. The use of two active ground electrodes 3, 5 simultaneously, as shown in FIGS. 7 and 8, has the advantage that a spark may be generated both in the gap between central electrode 2 and first ground electrode 3 and in the gap between central electrode 2 and third ground electrode 5. Even more reliable ignition of a combustible mixture may thus be achieved in particular. Otherwise, this exemplary embodiment corresponds to the preceding exemplary embodiments, so that reference may be made to the description given therein.
(21) FIGS. 9 and 10 show a spark plug 1 according to a fifth exemplary embodiment of the present invention. Identical or functionally identical parts are again identified by identical reference numerals as in the preceding exemplary embodiments.
(22) As shown in particular in the sectional view of FIG. 9, which is a section along line IX-IX of FIG. 10, spark plug 1 of the fifth exemplary embodiment essentially corresponds to that of the first exemplary embodiment. In contrast thereto, noble metal laminas 13, 14, 15, 16 are additionally also provided on ground electrodes 3, 4, 5, 6. The noble metal laminas improve the wear resistance of the ground electrodes, the ground electrodes being able to have a base pin manufactured from a cost-effective material. The base pins all have the same fundamental length. As shown in FIG. 9 in particular, the noble metal laminas are situated at different positions on ground electrodes 3, 4, 5, and 6. More precisely, noble metal lamina 13 of first ground electrode 3 is situated directly on free end 3c of first ground electrode 3. Noble metal lamina 14 of second ground electrode 4 is situated in such a way that there is a distance A1 from free end 4c of second ground electrode 4. Noble metal lamina 15 of third ground electrode 5 is situated in such a way that there is a distance A2 from free end 5c of third ground electrode 5. Distance A2 is greater than distance A1. Fourth noble metal lamina 16 is also situated in such a way that there is a distance (not shown in FIGS. 9 and 10) from free end 6c of fourth ground electrode 6, the distance at the fourth ground electrode being greater than distance A2 at the third ground electrode. By situating the noble metal lamina at different positions on ground electrodes 3, 4, 5, 6, which are otherwise equally long, the same function is obtained as in the third exemplary embodiment, namely that wear on central electrode 2 which also occurs during operation may be compensated for better by the varying positioning of the noble metal laminas. Because the noble metal laminas are each situated at different positions, they are selected after the bending-over procedure as the top ground electrode corresponding to the wear of central electrode 2 so that they lie directly diametrically opposite front side 2a of central electrode 2 after the bending-over procedure. Otherwise, this exemplary embodiment corresponds to the preceding exemplary embodiments, so that reference may be made to the description given there.
