File:Electrical ignition (1916) (14579520548).jpg

Identifier: electricaligniti00kawa (find matches)
Title: Electrical ignition
Year: 1916 (1910s)
Authors: Kawamoto, Tane
Subjects: Internal combustion engines Spark ignition engines Spark plugs Theses
Publisher:
Contributing Library: University of Illinois Urbana-Champaign
Digitizing Sponsor: University of Illinois Urbana-Champaign

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Text Appearing Before Image:
the decay-ing of secondary current follows exactly as equations (23)or (2?). Fig. 14 shows the shape of induced current in sec-ondary circuit with constant resistance of 7500 ohms acrossthe gap - Splitdorf. Thus the apparent resistance of the spark gap is afunction of the current density. We have the relation be- Pi<J 1-4- Firs/; Secondary Cvrt-<2ni~. $e<zondi C on ci<zr7 S - y tween the e.m.f. e across the plug points and spark currenti, which may he expressed in an equation: e ° * yrzk ----- w where e0 is voltage drop across the gap independent of thestrength of current flowing through the medium (gaseous mixt-ure in our case) K being a function of the spark gap lengthand is constant for any set of plugs which have definiteshape and length of the gap. The approximate values of eo and X. for a few knownsubstances may give more definite explanation of the equation(A): eQ = 13 volts for mercury vapor = 16 volts for zinc and cadium arc= 30 volts for magnetite arc
Text Appearing After Image:
U. OF S. ». FOBM 3 19 e0 - 36 volts for carbon arc, etc. K s 48.5 (t ♦ .125) for magnetite arc- 51 it - *Q) for carbon arc, etc.the complete equation of the magnetite and carbon arcs there-fore, a 7r and e = 3b + SI. ^f=^ similar constants exist for the spark plug points as theterminals of arc and gas as medium. The apparent resistance of the spark gap may also beexpressed in a function of lz, Irom the equation (A), the re-sistance across the plug points is rs = ( e. + jfej (8) Graph 2 shows the roughly approximated values of e and >5 forvarious values of the current in which eo is taken as 500volts and K equal to 11.25. The gap length being 1 mm. Prom graph 2 and the oscillograph it is evident thatthe increase of apparent spark gap resistance is so great, theflow of secondary current ceases abruptly. And this suddenchange of the spark current induces in the primary coil afurther disturbance producing an oscillatory current which isdamped out very quickly. The magnified view of

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