Method and apparatus for controlling air-fuel ratio in internal combustion engine

Patent · Tue Dec 02 04:00:00 EST 1986

OSTI ID:6956304

Kobayashi, N; Hattori, T

A method is described for controlling the air-fuel ratio in an internal combustion engine comprising the steps of: calculating a base fuel amount in accordance with predetermined parameters of the engine; detecting an air-fuel ratio of the engine; calculating an air-fuel ratio correction amount in accordance with the detected air-fuel ratio so that the air-fuel ratio of the engine is brought close to a predetermined air-fuel ratio; calculating a mean value of the air-fuel ratio correction amount; calculating a learning correction amount so that the mean value of the air-fuel correction amount is brought close to a predetermined value; setting a lower limit upon the learning correction among; determining whether or not the engine is in an idling state; determining whether or not the mean value of the air-fuel ratio correction amount is larger than the predetermined value, when the engine is in an idling state; determining whether or not the learning correction amount is larger than a lower limit reference value for the lower limit, when the engine is in an idling state; renewing the lower limit reference value in accordance with the learning correction amount, when the mean value of the air-fuel ratio correction amount is larger than the predetermined value and the learning correction amount is larger than the lower limit reference value; and adjusting the actual air-fuel ratio in accordance with the base fuel amount, the air-fuel ratio correction amount, and the learning correction amount.

• Assignee: Toyota Jidosha Kabushiki Kaisha, Toyota
• Patent Number(s): US 4625699
• OSTI ID: 6956304
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
330100* -- Internal Combustion Engines
COMPUTER CALCULATIONS
COMPUTERIZED CONTROL SYSTEMS
CONTROL SYSTEMS
CORRECTIONS
ENGINES
FUEL-AIR RATIO
HEAT ENGINES
INTERNAL COMBUSTION ENGINES
LEARNING