Spark plug having a creepage spark gap

Details Spark plug having a creepage spark gap Spark plug having a creepage spark gap

1996-01-19

1998-03-24

Patel, Ashok

Electric lamp and discharge devices

Spark plugs

Non-conducting material in or adjacent gap

313131R, 313141, 313123, 445 7, H01T 1352, H01T 1346

Patent

active

057316546

DESCRIPTION:

BRIEF SUMMARY
BACKGROUND OF THE INVENTION

The invention relates to a spark plug, particularly for an internal combustion engine of the generic type having at least one center electrode (high-voltage electrode) and at least one earth or ground electrode, and having an insulating spark plug insulator and a creepage spark cap between the center electrode and the earth electrode; as disclosed in, for example, in WO 87/07094.
Spark plugs having a creepage spark gap have significantly lower ignition voltages than spark plugs having the same electrode spacing but exclusively gas spark gaps. A disadvantage, however, is high breakdown discharges which lead to high temperatures in the region of the creepage path of the ceramic of the spark plug. The materials which can be used to produce a spark plug are therefore limited to materials which are resistant to high temperatures, for example Al.sub.2 O.sub.3 and high-melting-point metals and alloys.
To initiate ignition, it is necessary to facilitate sparking and increase the contact of the spark with the gas to be ignited. The efficiency of a spark plug corresponds to the quotient E.sub.ab /E.sub.zu of the energy released to the mixture to be ignited to the energy supplied to the spark plug. A spark plug has a high efficiency when little thermal energy from the energy of the ignition is dissipated by way of the solid, cold and thermally well-conducting electrodes. Solutions in the prior art have a relatively large contact surface of the flame core of the spark with the thermally well-conducting electrodes, because the small spacing between the electrodes decreases the contact surface of the spark with the ignition mixture.
It is the object of the invention to increase the efficiency of a spark plug, embody a maximum electrode spacing of the spark plug with an upwardly limited high voltage, or minimize the ignition voltage with a known electrode spacing.


SUMMARY OF THE INVENTION

The above object generally is accomplished by a spark plug, particularly for an internal combustion engine, having at least one center electrode (high-voltage electrode) and at least one earth electrode, an insulating spark plug insulator disposed between the center electrode and the earth electrode, and a creepage spark gap between the center electrode and the earth electrode at a combustion chamber end of the spark plug and wherein island-shaped patterns comprising electrically-conductive materials which are insulated with respect to one another are disposed on the outer surface of the insulator within the creepage spark gap having the characterizing features of the main claim. An extension of the creepage spark gap and thus of the electrode spacing with the same available ignition voltage is accomplished by the pattern of conductive islands which are insulated from one another and spaces between them, which are located on the surface zone of the spark plug insulator. The heat dissipation at the low ends of the spark or the flame core is reduced, and the contact surface of the flame core with the unburned mixture increases by means of transferring sparking from the intermediate spaces of the conductive islands to the envelope of the creepage spark gap.
Advantageous modifications of and improvements in the spark plug are possible with subsequently disclosed and described measures.
The creepage spark gap can be formed by the configuration of the conductive islands on an insulator, for example an insulating ceramic wafer applied to the spark plug insulator. Different ceramics can be used for the spark plug insulator and the ceramic wafer. Moreover, production of the conductive islands can take place separately, and the adherence of the islands to the insulator can be increased if need be by an intermediate layer. Dimensions of the islands having a diameter of 20 to 500 micrometers can be produced without costly production technology, and take into consideration the fact that, in order to prevent melting, the islands must have a defined minimum thermal capacity. The geometry of the islands is dimensioned su

REFERENCES:
patent: 1106703 (1914-08-01), Freiberg
patent: 1270437 (1918-06-01), Reppin
patent: 1415668 (1922-05-01), Marotta
patent: 1461405 (1923-07-01), Solomon
patent: 1505373 (1924-08-01), Carpenter
patent: 1991369 (1935-02-01), Berger
patent: 2129576 (1938-09-01), Gorney
patent: 5187404 (1993-02-01), Straub

Affiliated with

Also associated with

Rating

Spark plug having a creepage spark gap does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Spark plug having a creepage spark gap, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Spark plug having a creepage spark gap will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2291347