Patent GB-594437-A (GB)
Title: Ignition system for internal combustion engines
IPC: H04B15/02
Filed: 1945-06-15
Abstract: 594,437. Ignition systems. BENDIX AVIATION CORPORATION. June 15, 1945. No. 15290. Convention date, May 6, 1944. [Classes 7 (ii) and 7 (iv)] A double-bank radial internal-combustion engine has an ignition circuit comprising a generator which energises alternately two coils, one supplying through a distributor to the plugs in the cylinders of one bank and the other supplying through a second distributor the plugs in the cylinders of the other bank. In one form the engine has two banks, 11, 10 each of 9 cylinders arranged in staggered relation, and each cylinder has dual ignition by plugs 12, 13 for the rear bank and plugs 14, 15 for the front bank. Each plug is supplied with high voltage derived from individual transformers arranged in nine groups each with four transformers, each group supplying one cylinder in each bank through short shielded leads 33, Fig. 2, connected to the transformer secondaries through multiple plug-and-socket connections. Each transformer group is arranged in a metallic shielding casing 25 supported by a strap 26 lined with resilient material and bolted at 28 to valve tappet covers 27. Low voltage current at about 300 volts is supplied to the transformers through leads 35 which pass through a circular shielding manifold 36 and through short flexible conduits 38, such leads being connected to the transformer primaries through multiple plug-and-socket connections 39. The 'leads 35 extend through flexible conduits 40 to two similar distributors 41, 41<1>. Each distributor unit comprises two sets of nine contacts such as 42, 43, Fig. 4, to which the leads 35 are connected, and rotatable contacts elements 44, 45 rotating at half engine speed. One unit controls the front plugs of all the cylinders and the other the rear plugs of all cylinders so that the engine can run with single ignition in the case of failure of one distributor unit. The corresponding rings of contacts 43 and 43<1> in the two units both supply the front bank of cylinders and corresponding rings 42, 42<1> both supply the rear bank. The front cylinders are fired alternately with the rear cylinders. Each distributor incorporates two pairs of contact breakers M operated by separate nine-lobed cams and associated with a condenser C. Two further pairs of contact breakers B are associated with booster circuits described below. Energy is supplied to the distributors from a magneto 47 which comprises two four-pole magnetic rotors on a common shaft driven at one and one-eighth crankshaft speed. Each magnetic rotor is associated with two two-pole stators, each stator carrying a primary induction coil. The four coils 48-51, Fig. 4, are arranged so that coils 48, 49, are periodically simultaneously energised for firing the rear bank of cylinders while the coils 50, 51 are simuI- taneously energised alternatively with the coils 48, 49 for firing the front bank of cylinders, one rotor being advanced 45 degrees with respect to the other so that a firing of the front cylinders alternates with the firing of the rear cylinders and nine dual sparks are obtained from each revolution of the crankshaft. The coils 48-51 are connected through a detachable multiple plug-and-socket connector 52 to the distributor units and through a similar connector 54 to multiple ignition switches 55 which include a switch for each coil and a booster switch 58. From the magneto generator a typical lead such as 59, Fig. 4, has a branch 60 leading to a distributor arm and a branch 61 to the contact breaker. When the 'contacts are broken a surge at about 300 volts passes through one of the distributor contacts to the primary of a coil 24 and a higher voltage from the secondary causes a spark at a plug. Either the front or rear spark plugs in either bank may be rendered ineffective by means of the switchs 57. For starting, two booster coils 65, 66, Fig. 4, are arranged to supply 'the front spark plugs only in the cylinders 10, 11 respectively. The coil 65 has a winding 69 connected at one end to switch 58 and at the other through a resistance to booster contactbreakers B. The coil is supplied from a battery 75 and is associated with buzzer contacts 73. When the engine picks up speed the switch, 74 may be manually or automatically opened to cut out the booster coils. In a modification the coils 65, 66 may be replaced: by transformer windings having secondaries connected through normally open magnetically operated relay switches to the booster contact breakers. The switch actuating solenoids are connected to battery 75 when switch 74 is closed. Specifications 546,982, 584,861 and 594,445, [Group XXXV], are referred to.