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

Patent · Tue Mar 10 04:00:00 EST 1987

OSTI ID:6651541

Kobayashi, N; Hattori, T

A method is described for controlling an air-fuel ratio in an internal combustion engine having a throttle valve therein, comprising the steps of: detecting a concentration of a specific composition in an exhaust gas of the engine; calculating a predetermined target air-fuel ratio with respect to a stoichiometric air-fuel ratio in accordance with first predetermined parameters of the engine; controlling a feedback of the air-fuel ratio of the engine in accordance with the detected concentration of the specific composition so that the air-fuel ratio of the engine is brought close to the predetermined target air-fuel ratio; performing a fuel cut-off operation upon the engine in accordance with second predetermined parameters of the engine; calculating a fuel cut-off ratio as a total time cut-off operation of the engine during a definite time period; determining whether the fuel cut-off ratio is larger than a predetermined value; and stopping the feedback control of the air-fuel ratio of the engine when the fuel cut-off is larger than the predetermined value.

• Assignee: Toyota Jidosha Kabushiki Kaisha, Toyota
• Patent Number(s): US 4648370
• OSTI ID: 6651541
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
330100* -- Internal Combustion Engines
COMPUTERIZED CONTROL SYSTEMS
CONTROL EQUIPMENT
CONTROL SYSTEMS
ENGINES
EQUIPMENT
EXHAUST GASES
FEEDBACK
FLOW REGULATORS
FLUIDS
FUEL-AIR RATIO
GASEOUS WASTES
GASES
HEAT ENGINES
INTERNAL COMBUSTION ENGINES
STOICHIOMETRY
TIME DEPENDENCE
VALVES
WASTES