System for controlling the ignition timing of an internal combustion engine

Claim 1

A system for controlling the ignition timing of an internal combustion engine having an ignition timing control device, the system having a knock sensor for sensing engine knock and for producing a knock signal, sensing means for sensing operating conditions of the engine and for producing an engine operating condition signal, a table storing initial ignition timings, rough correcting means responsive to the knock signal and the engine operating condition signal for correcting an initial ignition timing derived from the table with a rough correcting quantity including a coefficient, thereby producing a basic ignition timing, fine correcting means responsive to the knock signal for correcting the basic ignition timing with a fine correcting quantity to produce a real ignition timing when the rough correcting quantity becomes a predetermined value, the system comprising: first detector means for detecting elapsed time from the start of the rough correcting operation and for producing a first change signal when a predetermined time elapsed during the rough correcting operation; first means responsive to the first change signal for ending the rough correcting operation and starting the fine correcting operation.

Claim 2

A system for controlling the ignition timing of an internal combustion engine having an ignition timing control device, the system having a knock sensor for sensing engine knock and for producing a knock signal, sensing means for sensing operating conditions of the engine and for producing an engine operating condition signal, a table storing initial ignition timings, rough correcting means responsive to the knock signal and the engine operating condition signal for correcting an initial ignition timing derived from the table with a rough correcting quantity including a coefficient, thereby producing a basic ignition timing, fine correcting means responsive to the knock signal for correcting the basic ignition timing with a fine correcting quantity to produce a real ignition timing when the rough correcting quantity becomes a predetermined value, the system comprising: first detector means for detecting elapsed time from the start of the rough correcting operation and for producing a first change signal when a predetermined time elapsed during the rough correcting operation; first means responsive to the first change signal for ending the rough correcting operation and starting the fine correcting operation.