Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
  • H01T13/00—Sparking plugs
  • H01T13/02—Details
  • H01T13/04—Means providing electrical connection to sparking plugs

Definitions

• the invention is based on a spark plug connector according to the preamble of the main claim.
• a spark plug connector known from DE-OS 29 08 051
• the one-piece insulating body is provided as a dielectric, in and on which a metallic cylinder is fastened.
• the cylinders serve as capacitor electrodes of a capacitor integrated in the spark plug connector, which is arranged parallel to the connection between the spark plug and the ignition cable and is discharged at the time of ignition. The discharge should be combined with the ignition current of the spark plug in order to obtain a strong ignition spark.
• the known insulating body as a dielectric, only a capacitance of the spark plug connector of up to 20 pF can be achieved, which is only able to store an insufficient amount of energy.
• the spark plug connector according to the invention with the characterizing features of the main claim has the advantage that it is economically feasible in that With a relatively small dielectric, the spark plug connector can be given a significantly higher capacity than in the known designs. As a result, the spark energy of the spark plug is amplified to such an extent that it can ignite even lean fuel-vapor-air mixtures safely and over a required service life in all operating states of an internal combustion engine.
• ring-like electrical insulating elements are arranged between the separating surfaces of the individual longitudinal sections, which run transversely through the insulating body, which lie firmly against the separating surfaces and consist of a material which is not rigid at all temperatures occurring in this area of the spark plug connector, but is elastic.
• the elements can consist, for example, of silicone rubber, of an appropriately adjusted epoxy resin or of polymerized plastics.
• the electrical insulating elements reliably prevent voltage breakdowns on the separating surfaces of the longitudinal section of the insulating body which forms the dielectric of the capacitor, although the separating surfaces extend in the direction of the electrical field lines at points of high electrical field strength.
• the parting surfaces of the longitudinal sections of the insulating body have a roughness depth R Z of less than 30 ⁇ m. This can be achieved with a glaze, for example. According to the German standard (DIN U768), the roughness depth is to be understood as the mean value from the individual roughnesses Z 1 to Z 5 of five successive individual measuring sections.
• a longitudinal section of the insulating body can advantageously also be designed as a sealing cap, which seals the insulator of the spark plug can be postponed. It is also advantageous to provide the metallic sheath, which at least partially surrounds the insulating body and is closed and attached to ground on the spark plug, as a suppressor jacket.
• the drawing shows a longitudinal section through a spark plug connector on an enlarged scale.
• a spark plug connector has an insulating body which is formed from three longitudinal sections 1, 2 and 3 and has a continuous longitudinal bore 4.
• a connecting part 5 made of electrically conductive metal is arranged in the longitudinal bore 4.
• one end 6 of the connecting part 5 protrudes from the longitudinal section 1 of the insulating body in order to be connected to an ignition cable (not shown) in a manner known per se and not shown in detail.
• the end 6 is provided with a thread onto which a threaded sleeve 7 is screwed until its flange 8 lies firmly against the outer end face 9 of the insulating body.
• the other end 10 of the connecting part 5 is firmly drawn with its flange 11 to an inner ring shoulder 12 of the longitudinal section 3 of the insulating body.
• the end 10 of the connection part 5 is provided with a blind hole as a receiving bore 13, into which a threaded end of a connecting bolt 14 of a spark plug 15 projects.
• the thread of the connecting bolt 14 snaps onto a spring ring 16 which is arranged on the outside on the end 10 of the connecting part 5 in an annular groove 17 and projects with a latching section 18 through a slot 19 into the receiving bore 13.
• the insulating body has at its ignition cable end the sleeve-shaped longitudinal section 1 made of ceramic insulating material, for example aluminum oxide or of a thermosetting plastic or thermoplastic with sufficient heat resistance.
• the end of the longitudinal section 1 facing away from the end face 9 is widened as a flange 20 and has an end face referred to as separating surface 21. It runs transversely to the longitudinal axis of the insulating body and thus of the spark plug connector.
• the separating surface 21 of the longitudinal section 1 has a surface whose roughness depth R Z should be as small as 30 ⁇ m as possible, preferably smaller than 5 ⁇ m. This low roughness can best be achieved by applying a glaze (not shown) to the separating surface 21, which has a layer thickness of less than 40 ⁇ m and can be produced, for example, from a commercially available glass paste No. 9137 from Dupont.
• a first electrical insulating element 22 which has the shape of an annular disk, lies tightly against the separating surface 21 of the longitudinal section 1 with one end face.
• an end face of the longitudinal section 2 referred to as the separating surface 23, lies tightly.
• the longitudinal section 2 is designed in the form of a cylinder sleeve as a dielectric component. Its other end face likewise forms a separating surface 24, which extends transversely to the longitudinal axis of the insulating body and against which a second electrical insulating element 25 lies tightly. It also has the shape of an annular disc.
• the second electrical insulating element 25 lies with its end face facing away from the dielectric component 2 against the end face 26 of the longitudinal section 3 of the insulating body.
• the two electrical insulating elements 22 and 25 consist of a material which is elastic at all temperatures occurring in this area of the spark plug connector.
• Such an electrical insulating element 22 or 25 can consist, for example, of an annular disk made of silicone rubber, which for example has a thickness of 1 mm and a Shore hardness of 50.
• the thickness of such electrical insulation elements 22, 25 can also be between 0.1 and 0.2 mm.
• Silicone rubbers can be used as a material that is applied liquid, soft or viscous on two separating surfaces (for example positions 21 and 26; 21 and 24; 23 and 24 or 23 and 26) and, if necessary, one after the longitudinal sections 1 to 3 of the insulating body have been joined Post-treatment (for example polymerization) is subjected.
• Post-treatment for example polymerization
• an epoxy resin or the like is suitable, which is set according to the required elasticity and to which fillers such as aluminum oxide, talc, silicate may have been added in a known manner to compensate for the different thermal expansion behavior of the longitudinal sections 1 to 3 of the insulating body.
• the electrical insulating elements 22, 25 can be designed as ring disks made of polymerized plastic, for example polyimide, polycarbonate, polyester, polytretrafluoroethylene, polyvinyl chloride.
• the dielectric component 2 which belongs to a capacitor of the spark plug connector, has the shape of a hollow cylinder and, with its portion of the longitudinal bore 4, concentrically surrounds a portion of the connecting part 5 near its end on the candle side.
• the separating surfaces 23 and 24 of the dielectric component 2 likewise have a low roughness depth R Z as that of the above-described separating surface 21 of the first longitudinal section 1. They can also be coated with a corresponding glaze known per se and not shown in detail.
• the peripheral surface 27 of the dielectric construction partly preferably has a diameter which is slightly smaller than the diameter of the flange 20 of the longitudinal section 1 of the insulating body.
• Both the circumferential surface 27 and the surface of the section of the longitudinal bore 4 belonging to the dielectric component 2 are provided with a surface coating, not shown, which supports the electrical contact and can, for example, consist of a silver-palladium alloy and is 10 ⁇ m thick.
• the dielectric component 2 consists of a material with a dielectric constant ⁇ r of 100 to 500.
• the dielectric component 2 can consist, for example, of a mixture of calcium titanate, barium titanate, strontium titanate, bismuth oxide and lead titanate or only of calcium titanate and strontium titanate.
• a commercially available suitable substance is supplied, for example, by the Japanese company Murata under type QQ or UF.
• the dielectric component 2 is dimensioned such that the spark plug connector has a capacitance of 50 to 500 pF, but preferably has a capacitance of 120 to 400 pF.
• the longitudinal section 3 of the insulating body which is in contact with the electrical insulating element 25 consists of a sufficiently elastic insulating material so that its tubular end section 28 can also be pushed onto the insulator 29 of the spark plug 15 in a sealing manner as a sealing cap.
• the end section 28 is relatively thin-walled. Its inner wall 30 delimits the connection space 31 in the circumferential direction between the spark plug connection pin 14 and the connection part 5. It starts from the inner ring shoulder 12, on which the flange 11 of the connection part 5 is kept tight.
• the outer jacket of the longitudinal section 3 has its outer diameter at its end abutting the electrical insulating element 25, merges into a tapering conical section in a central section 32 and continues in the smaller diameter cylindrical section of the end section 28.
• a plug housing 33 as an outer metallic sheath is essentially tubular. It is pushed so far over the insulating body that the flange 20 of the longitudinal section 1, the dielectric component 2 is completely accommodated in its inner bore 34, and the end section of the longitudinal section 3 provided with the outer diameter of the electrical insulating element 25.
• An expanding end section 35 of the inner bore 34 with a constant outer diameter of the plug housing 33 forms a plug-on section 36 of the spark plug plug onto the hexagon 37 of the spark plug 15.
• the plug-on section 36 is provided with narrow parallel longitudinal slots 38.
• the plug-on section 36 of the plug housing 33 is closed to ground by the hexagon 37 of the spark plug 15.
• the push-on section 36 can also be widened in a manner known per se at the free end and carry a tension spring in order to achieve good contact with the hexagon 37 serving as a ground connection.
• the free end of the plug-on section 36 also knew to be screwed onto the metallic transition from the hexagon 37 to the insulator 29 of the spark plug 15 in order to obtain a connection which was as uniform and tight as possible on the entire circumference of the plug-on section 36.
• the plug housing 33 is held on the insulating body 1 to 3 by an edge 39 placed around the outside of the flange 20 of the first longitudinal section 1 of the insulating body (for example by flanging).
• One end of a sealing spout 40 is also held by the edge 39. It is drawn onto the section of the first longitudinal section 1 protruding from the plug housing 33. Its other end sealingly surrounds the end section of the ignition cable, also not shown, in a manner known per se and not shown.
• the capacitor of the spark plug connector consists of the dielectric component 2, which forms only a relatively short longitudinal section of the insulating body, and also consists of the portion of the connecting part 5 enclosed by the dielectric component 2 and the portion of the plug housing 33 surrounding the dielectric component 2 as capacitor electrodes.
• the capacitor 2, 5, 33 is connected in parallel to the spark gap of the spark plug 15.
• a contact sleeve 41 and 42 is arranged between the respective opposite surfaces of parts 5 and 2 and 2 and 33 for the secure electrical connection of the roller-shaped section of the connection part 5 to the dielectric component 2 and of the dielectric component 2 to the plug housing 33 comprising the component 2 .
• the contact sleeves 41 and 42 can each consist, for example, of a steel mesh with a small mesh size (for example 200 to 300 ⁇ m) that is 0.1 to 0.5 mm thick.
• a small mesh size for example 200 to 300 ⁇ m
• other means supporting the electrical contact between the capacitor parts 5, 2, 33 with different thermal expansion behavior can also be used, for example an electrically conductive casting compound, graphite packing or the like.
• the annular space receiving the contact sleeve 41 and / or the contact sleeve 42 contains only gas instead of the contact sleeves 41 and 42.
• the annular spaces contain air and are .through the elastic ring-shaped electrical insulating elements 22; 25 sealed at the end faces.
• the annular spaces can each form a 0.01 mm to 0.50 mm wide annular gap.
• Each annular gap is preferably 0.05 mm to 0.30 mm wide.
• this condenser design is first of all the simpler design, since fewer parts are required and, for example, air is used as the means which supports the contact between the condenser parts 2, 5, 33 with different thermal expansion behavior.
• this capacitor form, arranged in the spark plug connector, for the spark plug, onto which the spark plug connector is plugged, has the effect that the conversion of energy during the glow and arc phase is relieved and thus the spark plug wear is reduced accordingly.
• the described embodiment of the spark plug connector can be regarded as a partially shielded spark plug connector. It can also serve as an intermediate connector, on the end 6 of which a spark plug connector can be inserted.
• a suppression resistor is arranged between the connection end of the connector part 5 for the spark plug and the connection end 6 for the ignition cable.
• the connection part 5 is divided such that the candle-side end projects through the dielectric component 2 into the first longitudinal section 1 of the insulating body and is electrically conductively and mechanically connected in the borehole section 4 of the longitudinal section 1 to one end of the interference-suppressing resistor accommodated there.
• the other end of the suppression resistor is then connected in a manner known per se to a connecting part of the ignition cable.
• the plug housing 33 forms both a capacitor electrode and an interference suppression jacket of the spark plug connector.
• the plug housing 33 as a suppressor jacket is still to be extended over the first longitudinal section 1 of the insulating body which comprises the suppressor resistor and its connection area to the ignition cable.

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• Spark Plugs (AREA)
• Connector Housings Or Holding Contact Members (AREA)

Priority Applications (1)

Applications Claiming Priority (4)

Publications (1)

Family

ID=25832716

Family Applications (1)

Country Status (4)

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Citations (2)

• 1986
  • 1986-01-10 DE DE19863600509 patent/DE3600509A1/de not_active Withdrawn
  • 1986-04-10 EP EP86902324A patent/EP0227693B1/de not_active Expired
  • 1986-04-10 WO PCT/DE1986/000155 patent/WO1986007206A1/de active IP Right Grant
  • 1986-04-10 DE DE8686902324T patent/DE3665517D1/de not_active Expired
  • 1986-05-30 ES ES555554A patent/ES8707825A1/es not_active Expired

Patent Citations (2)

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