GB664151A - Improvements relating to spark ignition apparatus for internal-combustion power plant - Google Patents

Abstract

664,151. Ignition system. LUCAS, Ltd., J. Jan. 2, 1950 [Jan. 12, 1949 ; Feb. 14, 1949 ; Aug. 9, 1949], Nos. 830/49, 3949/49 and 20670/49. Class 7(iv) [Also in Group XXXV] In an electric spark ignition apparatus comprising a pair of systems each including a condenser b, Fig. 1, a rectifier d through which the condenser can be charged and a control spark gap f, the two systems are adapted by their inter-action to ensure simultaneous spark discharges therein. The secondary winding a, of a transformer is connected to the pair of high-tension systems each of which has in parallel therewith the condenser b whilst between one end of the winding and each condensed is arranged the rectifier d so that the condensers receive alternate charges; in series with each condenser b and the ignition gap e is the control gap f. The two circuits are coupled by coils h, forming a mutual inductance; in order to effect simultaneous discharges of the ignition gaps; a condenser g connected across both gaps e may be used instead of, or in addition to, the coils h. The primary winding i, is in two parts each of which has a centre tapping j, both parts being connected through an interrupter to a source of cur- .rent. The interrupter comprises a pair of movable contacts m and two pairs of fixed contacts p so that current is alternatively supplied to the halves of each winding. Each condenser b, is progressively charged until the breakdown voltage of the control gaps f is reached, the discharge across these gaps causing simultaneous sparks at the ignition gaps e. A high resistance may be connected across each ignition gap and two identical interrupters may be used, the total current being shared between them. In a modification, the coils of the mutual inductance are dispensed with and replaced by inductances for prolonging the duration of the discharges; an inductance is also connected in the line from the other side of the secondary winding. The controls gaps are arranged adjacent each other so that a discharge across one will ionize and cause breakdown of the other. The primary winding comprises one coil with a centre tapping, and the interrupter is as shown in Fig. 1. the two. pairs of contacts sharing the total current whilst resistances are placed in series with the contacts. In another modification, two interconnected transformers are employed, and a mechanical or electromagnetic interrupter m, Fig. 4, is associated with each primary winding i; each condenser b, is connected to one end of secondary winding a through a rectifier d and each of the outer lines in the two secondary circuits embodies a choke u and the common line includes a choke c.