PURPOSE: To enable improvement of an output by a method wherein based on information on a feed fuel amount, and gasifying characteristics and an octane number preset classified by a component, the octane number of fuel in a combustion chamber is estimated, and an ignition timing is determined according to the estimated octane number.
CONSTITUTION: An octane number estimating means 22 of an ECU 15 has an estimating means 22A estimating a gasifying and suction amount and a calculating means 22B calculating an equivalent octane number of fuel in a combustion chamber 1, based on information on a feed fuel amount obtained by a measuring means 20, a component ratio, gasifying characteristics, and an octane number preset classified by a fuel component by means of a setting means 21. An ignition timing calculating means 23 selects either of a plurality of ignition timing maps 231 - 23n based on the estimated equivalent octane number, an ignition timing is determined through map retrieve of an ignition timing responding to signals from a load sensor 13 and a number of revolutions of engine sensor 14 to output it to an ignition signal generating means 24. This constitution enables reliable prevention of the occurrence of knock as acceleration performance is maintained.
KOJIMA KAZUHIRO
ANDO HIROMITSU
TAKEMURA JUN
KAMISHINA HIDEKAZU
| JPH0240057A | 1990-02-08 |