JPS6478165A - Engine tachometer driving device - Google Patents

Abstract

PURPOSE:To obtain at a low cost a driving device which can adjust a transient response characteristic in accordance with the magnitude of an engine revolution variation rate by driving the device by a driving pulse signal synchronizing with an engine revolution signal, and also, corresponding to the magnitude of the revolution variation rate. CONSTITUTION:A pulse generator 1 generates six pieces of constant-angle pulses at every rotation of a crank shaft and supplies them to a waveform shaping circuit 2. As for this constant-angle pulse, its period is varied due to the variation of the revolution of an engine. A constant-angle pulse signal brought to waveform shaping by the circuit 2 is supplied to an acceleration/deceleration detecting circuit 3 and a trigger terminal of a ring counter 4. The constant-angle pulse signal is converted to a voltage signal being proportional to the revolution of the engine by an F/V converter 5 of the circuit 3, and thereafter, differentiated 6 and converted to an electric signal for showing the variation rate of the revolution of the engine, and supplied to non-inversion input terminals of comparators A1-A6 of a comparator 7. Six pieces of outputs from the circuit 7 and the ring counter 4 pass through AND circuits B1-B6 and an OR circuit 8 and supplied to a driving pulse generating circuit 10, and supplied as a driving pulse of prescribed width to an engine tachometer 9.