Air-fuel ratio control method for internal combustion engines

Patent · Tue Sep 22 04:00:00 EDT 1987

OSTI ID:6042234

Yatabe, F; Wazaki, Y

This patent describes 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, 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. The method comprising the steps of: (1) providing a low-load operating region of the engine lying outside the feedback control region and defined by at least one parameter representing load on the engine; (2) determining, when the engine enters the low-load operating region. A value of the correction coefficient is in response to the output from the means for detecting the exhaust gas ingredient concentration and also calculating an average value of values of the correction coefficient thus determined, for a predetermined period of time after the engine enters the low-load operating region; (3) calculating a target value of the correction coefficient on the basis of the average value obtained in the step (2), the target value yielding a predetermined air-fuel ratio leaner than a stoichiometric mixture ratio; (4) varying the value of the correction coefficient after the lapse of the predetermined period of time and until it becomes equal to the target value while the engine remains in the low-load operation region; and (5) correcting the basic fuel supply quantity by the use of the value of the correction coefficient thus varied.

• Assignee: Honda Giken Kogyo K.K., Tokyo
• Patent Number(s): US 4694805
• OSTI ID: 6042234
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
330100* -- Internal Combustion Engines
CHEMICAL COMPOSITION
COMBUSTION CONTROL
CONTROL
CONTROL SYSTEMS
CORRECTIONS
DISPERSIONS
DYNAMIC LOADS
ENGINES
EXHAUST GASES
FEEDBACK
FLUIDS
FUEL INJECTION SYSTEMS
FUEL SYSTEMS
FUEL-AIR RATIO
FUNCTIONS
GASEOUS WASTES
GASES
HEAT ENGINES
INTERNAL COMBUSTION ENGINES
METERING
MIXING
MIXTURES
MONITORING
OPERATION
RESPONSE FUNCTIONS
STOICHIOMETRY
TIME DEPENDENCE
WASTES