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
  • H01T13/20—Sparking plugs characterised by features of the electrodes or insulation
  • H01T13/39—Selection of materials for electrodes
• • 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
  • H01T13/40—Sparking plugs structurally combined with other devices

Definitions

• the invention relates to a spark plug for internal combustion engines as is already known from DE-OS 44 31 143.
• a spark plug is proposed that has little wear.
• Spark plug is inserted in a cylindrical metal tube, which forms the housing, a rod-shaped inner conductor, which is surrounded by an insulator and has a current-limiting resistor in the circuit of the spark plug, the current-limiting resistor being arranged in such a way that it is in
• the electrode head of the inner conductor is also coated with a noble metal layer and a good heat-conducting material is provided as the electrode head, which also serves as a heat buffer.
• the spark plug with the features of the main claim has the advantage over the known that by Forming the electrode in the form of a "nail head" more wear volume is available. Furthermore, by reducing the diameter of the contact pin and shortening the length, as well as by the advanced burn-off resistance, lower mechanical stresses are achieved by different
• Coefficient of thermal expansion can occur. By reducing the electrode erosion, ceramic notches are ultimately largely avoided. Another advantage is the coating of the contact pin, which provides high corrosion resistance. Ultimately, the single or double bend of the ground electrode and the protrusion of the ground electrode beyond the end face of the insulator also have the advantage that ceramic breakdowns can be prevented by this design of the electrical field.
• the measures listed in the subclaims enable advantageous developments and improvements of the spark plug specified in the main claim. It is particularly advantageous to dope the platinum electrode. This doping prevents corrosion of the contact pin, since the platinum electrode is sintered gas-tight into the ceramic. A gas-tight connection of the platinum electrode, the ceramic and the contact pin by means of an active solder also prevents contact pin corrosion and prevents the contact pin from being withdrawn. Ultimately, the contact pin can be replaced by an electrically conductive ceramic-metal mixture, likewise a
• Figure 1 shows a spark plug according to the invention in a schematic representation
• Figure 2 shows the combustion chamber end of the spark plug according to the invention with different electrodes electrodes.
• FIG. 1 shows schematically the inner part of a spark plug in a partially sectioned representation.
• An insulator 11 is arranged in a metallic, tubular housing 10, the rotationally symmetrical axes of the housing 10 and insulator 11 being congruent.
• Embedded in the insulator 11 is the central electrode 12, as well as the individual components to be explained below for transmitting the voltage from the connecting bolt 13 to the central electrode 12.
• the connecting bolt 13 is connected to the burn-up resistor 14 in the interior of the insulator 11.
• the erosion resistor 14 is connected to the contact pin 15, so that the voltage is transmitted to the center electrode 12 via the contact pin 15.
• the center electrode 12 is made of platinum and has essentially the shape of a nail. This means that the rear part of the platinum center electrode 12 has a much smaller diameter than the combustion chamber-side part of the platinum center electrode, which looks out of the insulator 11.
• the contact pin 15 itself is coated with a corrosion protection layer, for example with nickel or with a nickel-silver alloy.
• the Contact pin 15 compared to conventional spark plugs significantly shortened in length and reduced in diameter. By shortening the contact pin 15, the erosion resistance is extended and further advanced in the direction of the spark gap, which has the advantages as already described in DE-OS 44 31 143.
• the ground electrodes 16 are attached to the housing 10 and bent toward the center electrode.
• the ground electrodes are bent twice.
• the ground electrode attached to the housing is first bent in the direction of the center electrode and then bent again in the axial direction a second time, so that the end face of the ground electrode points in the axial direction of the spark plug.
• the end face of the ground electrode 16 projects beyond the end face of the insulator by a predeterminable amount.
• the size of the protrusion corresponds approximately to the thickness of a ground electrode.
• FIG. 2 shows the spark plug with the essentially same design as that shown in FIG. 1.
• the only difference to Figure 1 is the position of the ground electrodes.
• the ground electrodes are bent only once, whereby the end face of the ground electrode points in the radial direction of the spark plug.
• ground electrodes project about their thickness beyond the front of the insulator. This results in a favorable formation of the electric field, which avoids ceramic breakdowns.
• the platinum center electrode can also be coated, whereby this coating can be carried out by means of boriding, alitriding, nitriding or siliconizing. This coating allows the platinum electrode to be sintered into the ceramic gas-tight.
• the connection of platinum The center electrode, insulator and contact pin with a solder also contribute to a gas-tight connection, thereby preventing contact pin corrosion and preventing the contact pin from being pulled back.
• the contact pin can ultimately also be replaced by an electrically conductive ceramic metal layer.

Applications Claiming Priority (3)

Publications (2)

Family

ID=7797078

Family Applications (1)

Country Status (7)

Families Citing this family (21)

Family Cites Families (16)

• 1996
  • 1996-06-15 DE DE19623989A patent/DE19623989C2/de not_active Expired - Fee Related
• 1997
  • 1997-05-22 US US09/011,843 patent/US5952770A/en not_active Expired - Fee Related
  • 1997-05-22 CN CN97190628A patent/CN1064483C/zh not_active Expired - Fee Related
  • 1997-05-22 DE DE59709144T patent/DE59709144D1/de not_active Expired - Fee Related
  • 1997-05-22 EP EP97930294A patent/EP0845167B1/de not_active Expired - Lifetime
  • 1997-05-22 WO PCT/DE1997/001025 patent/WO1997049153A1/de active IP Right Grant
  • 1997-05-22 BR BR9706533A patent/BR9706533A/pt not_active Application Discontinuation
  • 1997-05-22 JP JP10502051A patent/JPH11510958A/ja not_active Ceased

Non-Patent Citations (1)

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