GB574775A - Improvements in high frequency electrical ignition systems - Google Patents

Abstract

574,775. Ignition systems. BRITISH THOMSON-HOUSTON CO., Ltd., WELCH, D. F., and GRIEVE, A. Sept. 7, 1942, No. 12612. [Class 7 (iv)] A high-frequency system comprises a hightension intermittent-voltage generator 1 such as a magneto or coil, a spark gap 6 in series with a distributer 5 and a condenser C<1> in shunt with the circuit to cause, on breakdown of the spark gap, high-frequency oscillations to be supplied through the distributer to a spark plug 8, and an inductance 9 connected in series with and situated in or near to the plug in order to limit the peak H.F. current supplied thereto. In one form, Fig. 1, the secondary winding 3 of the generator 1 is connected through the spark gap 6 and an inductance 10 to the distributer 5, from which shielded conductors 7 each lead through the series inductance 9 to a spark plug 8. A resistance 11 is connected in shunt with the distributer as in Specification 560,459, [Group XIX]. The capacitance to earth of the lead 7 and plug 8 is indicated by condensers C<2>, C<3>. The spark gap 6 is preferably of the sealed type as described in Specification 574,452, [Group XL]. In modifications : (a) a high-frequency transformer 12, Fig. 2, is interposed between the gap 6 and the distributer 5 ; (b) a highfrequency inductance replaces the transformer 12 ; (c) an auxiliary spark gap 14 and inductance 15, Fig. 4, connected in series, are provided in shunt with the distributer for byepassing part of the high-frequency discharge and so increasing the maximum open-circuit voltage available at the plug. The gap 14 and inductance 15 may be connected on the plug side of the distributer, a separate gap and inductance then being necessary for each plug circuit. Specification 530,601 also is referred to.