Patent GB-732888-A (GB)
Title: High frequency ignition systems
Inventor: HARMON KENNETH ALLEN
IPC: F02P1/08
Filed: 1953-11-30
Abstract: 732,888. Ignition systems. WICO ELECTRIC CO. Nov. 30, 1953, No. 33224/53. Class 7(4). [Also in Group XXXV] Circuit arrangement. In an H.F. ignition system comprising an A.C. generator 10, 11, a vibrator 24 for generating in one winding, such as the armature winding 14, an E.M.F. independently of the relative speed between the stationary armature 20 and rotating field 11, the vibrator 24 having a stationary contact 26, and a magnetic resilient support 23 provided with a movable contact 25, an electromagnet 45 to attract the support 23 and disengage contacts 25, 26 which are adapted to be connected in series with the field winding 15 and a battery 34, there is an energising circuit for the electromagnet winding 46 which is adapted to be connected to the battery in parallel with the field winding 15 and which includes in series the electromagnet winding 46, the contacts 25, 26 and a control switch 48, whereby when the latter is closed the contacts 25, 26 operate at a H.F. determine by the resiliency of the support 23 to energise the sparking plugs 9. The armature 10 and field magnet 11 have the same number of radial cores 12 and 13, respectively, as there are engine cylinders or a multiple thereof; the coils 14 and the cores 12 are serially connected as are the coils 15 on the cores 13. The two ends of the field winding are connected to slip rings 18, 19, the associated brushes 20, 21 being wired, respectively, to the battery 34 through the ignition switch 32, and the vibrator 24, the contacts 25, 26 of which are closed when the vibrator is not in use. The ends of the armature winding are connected to a full-wave rectifier 3 across the output terminals 39, 40 of which is placed a condenser 2, one terminal 39 being earthed and the other connected to the rotor arm 4 of a distributer having each of its fixed contacts joined to a sparking plug 9 through a transformer 7, 8 ; the rotor 11, slip rings 18, 19 and distributer rotor are on a common shaft 5. The switch 48 is operated by an electromagnet 54 the coil of which is energised from the battery 34 upon actuation of a push-button switch 56, the switch 48 or one operated therewith controlling the circuit to a starter motor 52. A half-wave rectifier may replace the full-wave rectifier shown. Starting. Upon operating the switch 56 the motor 52 is energised and the contacts 25, 26 operate to produce a pulsating current in the field winding 15 and thereby charge the condenser 2, the generator windings acting as a transformer ; charging current may be applied several times to the condenser during the interval in which the rotor 11 moves an angular distance equal to that between two successive poles so that the normal rotating field is rapidly interrupted and becomes ineffective. Normal operation. When the switch 56 is released the vibrator 24 ceases to operate and the field winding 15 is energised directly from the battery 34 to establish a rotating field. Each alternation of the generator producing a spark, the condenser 2 receiving as many charges per revolution of the rotor 11 as there are cores 13. As the rotor arm 4 approaches a fixed contact the gap between them is ionized and the condenser will discharge across the gap ; when the contacts touch, further charging of the condenser is prevented. The distributer also functions as the spark timing means.