GB809989A - Improvements in or relating to ignition systems for internal combustion engines - Google Patents

Abstract

809,989. Ignition systems. GENERAL MOTORS CORPORATION. April 10, 1957 [April 19, 1956], No. 11716/57. Class 7(4) A p-n-p or n-p-n junction transistor 28 controls the current flow in the primary 32 of the ignition coil. The transistor conducts when an interrupter 38 connects its base b to a tap 40 on a resistance 42. When the current ceases the stored energy in the ignition coil will be released for energization of the spark plugs. The characteristics of the transistor are such that a current of about 8 to 10 amperes will flow whenever the base b is sufficiently negative with respect to the emitter e and the emitter e is sufficiently positive with respect to the collector. Thus the inductance of the primary circuit can be reduced to a lower value than is used in present day systems. The transistor will not pass current from the emitter e to a collector c when the voltage in either direction approaches 1000 volts if the base b is not supplied with current. The variable resistance 42 may be replaced by a fixed tapped resistance. Alternatively two fixed resistances may be used instead of a tapped restistance. A condenser 46 minimizes voltage surges.