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

Patent · Tue Jan 19 04:00:00 EST 1988

OSTI ID:5280942

Kobayashi, N; Hattori, T; Ito, T

A method for controlling the air-fuel ratio in an internal combustion engine having a throttle valve therein, is described comprising the steps of: detecting an intake air pressure of the engine; detecting an opening of the throttle valve; controlling the air-fuel ratio of the engine so that the air-fuel ratio is close to a power fuel increment air-fuel ratio by which a torque output of the engine is at a maximum when the opening the throttle valve is larger than a first predetermined value; calculating a first target air-fuel ratio which changes continuously in accordance with the detected intake air pressure and which is leaner than the power fuel increment air-fuel ratio, when the opening of the throttle valve is between the first predetermined value and a second predetermined value smaller than first predetermined value; loading a second target air-fuel ratio independent of the detected intake air pressure, controlling a feedback of the air-fuel ratio of the engine so that the air-fuel ratio approaches a richer air-fuel ratio between the first and second target air-fuel ratios, when the opening of the throttle valve is between the first and second predetermined values; and controlling the feedback of the air-fuel ratio of the engine so that the air-fuel ratio approaches the first target air-fuel ratio, when the opening of the throttle valve is smaller than the second predetermined value.

• Assignee: Toyota Jidosha Kabushiki Kaisha, Tokyo
• Patent Number(s): US 4719888
• OSTI ID: 5280942
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
330100* -- Internal Combustion Engines
AIR FLOW
CONTROL EQUIPMENT
CONTROL SYSTEMS
DETECTION
ENGINES
EQUIPMENT
FEEDBACK
FLOW REGULATORS
FLUID FLOW
FUEL INJECTION SYSTEMS
FUEL SYSTEMS
FUEL-AIR RATIO
GAS FLOW
HEAT ENGINES
INTERNAL COMBUSTION ENGINES
OPERATION
VALVES