GB1479967A - Engine starting control system - Google Patents

Abstract

1479967 Starting prime movers AUTOMATIC SWITCH CO 18 Sept 1974 [12 Nov 1973] 40621/74 Heading H2H In an engine starting system, a solid state counter 67 is arranged to provide a plurality of pulses for closing and opening a starter solenoid a plurality of times so as to periodically crank the engine and means responsive to a predetermined number of said pulses for terminating the output of pulses from the counter and hence terminating engine cranking. Fig. 1 (not shown) depicts a block diagram including a manual starting button and fault detecting devices. When the manual starting button is operated, power is supplied via transistor 56 to a silicon controlled switch 62 or programmable unijunction transistor PUT which presets the counter 67 for a count of four. A further PUT 80 is arranged to supply pulses along line 79 to counter 67. After a predetermined number of such pulses, a pulse is fed on line 66 to energize a crank drive circuit (Fig. 2, not shown) comprising a relay operated by a pair of transistors and arranged to control the starter solenoid. After four attempts to start the engine, the signal on the counter output line 76, 77, 78 will be such as to turn on transistor 90 the output of which is fed via a fault circuit 25 so as to turn off transistor, 109 and 56 and so inhibit further cranking. When the engine starts, a signal from speed switch 100 charges capacitor 103 which turns on transistor 106 so as to turn off transistors 109 and 56 so as to inhibit further cranking. When the engine is stopped, the signal from the speed switch disappears and capacitor 103 discharges over a predetermined period via constant current diode 104 so as to maintain transistor 106 conductive for the predetermined period and thus inhibit further cranking for that period. Fig. 6 (not shown) depicts a block diagram of a counter 67 which comprises four flip-flops in cascade. Figs. 1 and 5 (not shown) relate to circuits using controlled rectifiers which turn off the fuel control valve in the event of low oil pressure, high water temperature or excessive speed.