Air-fuel ratio control method for internal combustion engines

Patent · Tue Jun 21 04:00:00 EDT 1988

OSTI ID:7009402

Yatabe, F; Wazaki, Y

A method of effecting feedback control of the air-fuel ratio of an air-fuel mixture being supplied to an internal combustion engine having an exhaust passage and means arranged in the exhaust passage for detecting the concentration of an exhaust gas ingredient, to a first predetermined value, by correcting a basic fuel supply quantity by the use of a correction coefficient variable in value in response to an output from the means for detecting the exhaust gas ingredient concentration, when the engine is operating in a predetermined feedback control region. The method is described comprising the steps of: (1) providing a low-load operating region of the engine lying outside the predetermined feedback control region and defined by at least one parameter representing load on the engine; (2) gradually decreasing the correction coefficient until the air-fuel ratio of the air-fuel mixture is increased to a second predetermined value which is leaner than the first predetermined value, when the engine enters the predetermined low-load operating region; (3) when the engine enters the predetermined feedback control region from the predetermined low-load operating region, setting an initial value of the correction coefficient to the product of a value of the correction coefficient obtained immediately before the engine enters the predetermined feedback control region and a predetermined enriching coefficient; and (4) gradually increasing the initial value of the correction coefficient until the air-fuel ratio of the air-fuel mixture is decreased to the first predetermined value.

• Assignee: Honda Giken Kogyo K.K., Tokyo
• Patent Number(s): US 4751906
• OSTI ID: 7009402
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
330100* -- Internal Combustion Engines
CONTROL SYSTEMS
CORRECTIONS
ENGINES
EXHAUST GASES
EXHAUST SYSTEMS
FEEDBACK
FLUIDS
FUEL SYSTEMS
FUEL-AIR RATIO
GASEOUS WASTES
GASES
HEAT ENGINES
INTERNAL COMBUSTION ENGINES
OPERATION
WASTES