PURPOSE: To improve the fuel consumption of multi-cylinder internal combustion engine and to reduce the production of detrimental components in exhaust gas in the fuel supply device for the engine by shutting off fuel supply to part of the cylinders at engine low speed time.
CONSTITUTION: There are provided an air amount regulator 6 and a throttle valve 8 at the suction manifold 2 of a multi-cylinder internal combustion engine 1, and a catalytic unit 4 at the exhaust manifold 3 thereof. Then, signals from the regulator 6 and valve 8 are applied to a fuel injection control circuit 5 and a timer circuit 11, respectively. That is, when the throttle valve is fully closed such as when the engine is rotated at low speed, the signals are applied through the timer circuit 11 and an AND gate 10 to the control circuit 5 as a pulse signal only for predetermined time. Thus, the control circuit 5 shuts off fuel supplt to part of the cylinders.
IIZUKA HARUHIKO
SUGASAWA FUKASHI
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