Control device of an internal combustion engine

A control device for an internal combustion engine having a transmission, an intake passage, an acceleration pedal, and a spark plug arranged in a combustion chamber;

• said device comprising:
• fuel supply means disposed in said intake passage, adapted for feeding fuel into said intake passage;
• discriminating means for discriminating whether said acceleration pedal is released and then depressed and whether a speed of said engine decreases by a predetermined amount within a predetermined time period after said acceleration pedal is depressed after said release, and for producing an output signal indicating that said acceleration pedal is released and then depressed and that the speed of said engine decreases by said predetermined amount within said predetermined time period after said acceleration pedal is depressed after said release;
• fuel supply control means, connected to said fuel supply means and controlled in response to the output signal of said discriminating means, for normally forming a lean air-fuel mixture in said intake passage and for temporarily forming a rich air-fuel mixture in said intake passage when said acceleration pedal is released and then the engine speed is decreased by said predetermined speed within said predetermined time period after said acceleration pedal is depressed after said release;
• and,
• ignition timing means, connected to said spark plug and controlled in response to the output signal of said discriminating means, for normally causing ignition at a predetermined basic ignition timing and for temporarily retarding the ignition timing relative to said basic ignition timing when said acceleration pedal is released and then the engine speed is decreased by said predetermined speed within said predetermined time period after said acceleration pedal is depressed after said release.