Patent GB-801241-A (GB)
Title: Ignition system
IPC: F02P9/00
Filed: 1956-08-17
Abstract: 801,241. Igniting burners. BENDIX AVIATION CORPORATION. Aug. 17, 1956 [Aug. 23, 1955], No. 25240/56. Classes 75(1) and 75(3) [Also in Group XXVII] Either, in an electrical apparatus for controlling the flow and effecting the ignition of fuel in an engine comprising a magneto generator 5 having a winding 7 in which electrical energy is generated to energize an ignition circuit connected across a first portion 8, 9 of the winding and a control circuit including a solenoid 35 connected across a second portion 9, 10 of the winding, means are provided for short circuiting a third portion 9 of the winding to render the ignition and control circuits ineffective, or, in an electrical apparatus for an engine having a fuel supply line 44 in which the flow is controlled by a valve 43 operated by electromagnetic means, e.g. the solenoid 35, and a source of electrical energy, e.g. the magneto generator 5, energizing a circuit including an igniter gap for igniting the fuel and a circuit including the solenoid 35, means are provided operable in response to the speed of the engine exceeding a predetermined value to sufficiently limit without interrupting the supply of energy from the magneto-generator to the circuits to render the igniter gap and the solenoid 35 inoperative. The apparatus controls the supply and ignition of fuel to a supplemental combustion chamber adapted to ignite the main combustion chamber of a gas turbine engine. The ignition circuit comprises two similar circuits for energizing two spark plugs 14, 15 having semicondutors 16 bridging their sparking electrodes. The circuit for spark plug 14 includes two rectifiers 17 which charge a storage condenser 18. The discharge is controlled by a three-electrode spark gap device 20 having a first gap 21, 22 shunted by a semi-conductor or resistor 23 and a main gap 21, 24. A sealed control gap 25 is connected in series with is small condenser 26 between electrode 22 and earth G. In operation the condenser 18 charges and eventually the control gap 25 conducts, the flow of current across gap 21, 22 ionizing the main gap 21, 24. The condenser then discharges across the sparking plug. The discharge voltage may be stepped up by a transformer. The corresponding rectifiers 17<SP>1</SP> for the other spark plug 15 pass current of opposite polarity to that passed by the rectifiers 17 and are connected to the winding 7 through a resistance 28. The control circuit for energizing the solenoid 35 to open the fuel valve 43 includes two half wave rectifiers 36, 37 connected to conduct alternately and having starting electrodes connected to the supply line through resistors 40. The third portion 9 of the magneto winding 7 is short circuited by a centrifugal or pressure switch 29 responsive to the engine speed. The switch 29 can be rendered ineffective by a manually operated series switch 30. A further switch 45 is arranged in parallel with the switches 29, 30 and is connected to the throttle 46 which controls the fuel supply to the main combustion chamber of the engine to open therewith. The voltage of the discharge from the ignition condenser 18 may be stepped up by a transformer. U.S.A. Specification 2,684,665 is referred to.