GB1431773A - Control systems for internal combustion engines - Google Patents

Abstract

1431773 Engine control systems LUCAS ELECTRICAL CO Ltd 2 July 1973 [15 July 1972] 33236/72 Heading G3N [Also in Division F 1] An engine control system for controlling an operating parameter such as fuel injection quantity or the timing of sparks, comprises at least two transducers 11, 12 producing outputs dependent upon the values of engine parameters, e.g. selected from throttle angle, manifold depression, and engine speed, a memory unit 13 to which the outputs are fed, the memory unit producing a binary output dependent on the signals received from the transducers, control means 15 operable in accordance with the value of the binary output for controlling the operating parameter, and a binary converter 14 coupling the binary output to the. control means, the binary converter changing the number of bits in the binary output so as to reduce the minimum attainable change in the operating parameter. The memory unit is shown in Fig. 2. The transducer 12 energizes one of lines 12a - 12d in dependence upon its analogue output. The lines 12a - 12d serve when energized to operate respectively four switches 16a - 16d and each switch serves, when it is operated, to couple one of four sets of four lines 17a - 17d to the output lines 13a - 13d. The transducer 11 also energizes one of four lines 11a - 11d in dependence upon its analogue output, each of the lines 11 crossing each of the lines 17 with selected connections being made between the two sets of lines by diodes. Thus depending upon which of lines 11a - lid and which of lines 12a - 12d are energized, an appropriate four-bit binary output is supplied on lines 13a - 13d. The converter (14), Fig. 3 (not shown), then converts the four-bit binary output to a five-bit binary output. The control means may be a fuel injection pump.