Method of air/fuel ratio control for internal combustion engine

Patent · Tue Dec 06 04:00:00 EST 1988

OSTI ID:6232792

Nakajima, T; Okada, Y; Mieno, T; Oono, N

This patent describes a method for controlling an air/fuel ratio of a mixture supplied to an internal combustion engine equipped with an oxygen concentration sensor disposed in an exhaust system by producing an output varying substantially in proportion to an oxygen concentration in an exhaust gas of the engine. The method consists of: setting a basic value to control the air/fuel ration, in response to engine operating parameters relating to engine load; detecting the actual air/fuel ratio of the mixture based upon the oxygen concentration sensor output; compensating the basic value by an air/fuel ratio feedback compensation value which is derived in response to a deviation of the detected air/fuel ratio from a target air/fuel ratio and by a learning control compensation value which compensates for an error of the oxygen concentration sensor occurring due to infrequent changes in values of the sensor's characteristics, thereby determining an output value with respect to the target air/fuel ratio; controlling the air/fuel ratio of the mixture in response to the output value; and computing and updating the learning control compensation value when an absolute value of the deviation is lower than a predetermined value.

• Assignee: Honda Giken Kogyo Kabushiki Kaisha, Tokyo
• Patent Number(s): US 4788958
• OSTI ID: 6232792
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
330100* -- Internal Combustion Engines
99 GENERAL AND MISCELLANEOUS
990220 -- Computers
Computerized Models
& Computer Programs-- (1987-1989)
COMPUTERIZED CONTROL SYSTEMS
CONTROL SYSTEMS
DETECTION
ELEMENTS
ENGINES
ENRICHMENT
EXHAUST SYSTEMS
FUEL SYSTEMS
FUEL-AIR RATIO
HEAT ENGINES
INTERNAL COMBUSTION ENGINES
MEASURING INSTRUMENTS
METERING
METERS
NONMETALS
OXYGEN
OXYGEN ENRICHMENT