GB1399687A - Internal combustion engine having a monitoring device for limiting speed - Google Patents

Abstract

1399687 Regulating I C engines; ignition systems ROBERT BOSCH GmbH 16 Aug 1973 [17 Aug 1972] 38712/73 Heading G1N [Also in Division F1] A capacitor-discharge ignition-circuit includes a speed limiting section responsive to the rate of ignition pulses to temporarily disable the capacitor charging circuit. TIMING PULSE. The pulse from contactbreaker 36 is differentiated at 41, 47 and amplified by transistor pair 44, 57 having an output point 61 This pulse at point 61 is applied via line 7 to the rate circuit; diode 94 to the charging circuit; and firing control circuit 62, 72. The time constant of the differentiating circuit supresses pulses due to contact bounce. IGNITION CIRCUIT. The pulse from the firing control circuit 62., 72 is applied to the gate of thyristor 68 to discharge the ignition capacitor 70 through the coil 77. CHARGING CIRCUIT, comprises a transistor 26 with a feedback transformer 86, and an output pulse-transformer 81. When stimulated by a timing pulse through diode 94 transistor 26 conducts until the feedback voltage across transformer 86 causes thyristor 28 to break down, cutting off transistor 26 so that inductive pulse is produced in transformer 81 to charge the ignition capacitor 20 through diode 23. An overspeed signal from the rate circuit will appear on line 101 to bias thyristor to a conducting state so that charging pulses are not generated. SPEED/RATE CIRCUIT. The timing pulses on line 7 are applied to an integrator capacitor (3) with pre-set leak resistors (13, 14) Fig. 1 (not shown). The voltage across the capacitor is applied to an amplitude sensitive switch comprising a transistor 110, Fig. 4, which controls the firing of thyristor 107 to apply a disabling signal on line 101 to the charging circuit.