Double air-fuel ratio sensor system having improved response characteristics

Patent · Tue Sep 15 04:00:00 EDT 1987

OSTI ID:5908220

Chujo, Y; Kayanuma, N; Bessho, H; Masui, T; Nagai, T; Katsuno, T; Tanahashi, T

This patent describes a method for controlling the air-fuel ratio in an internal combustion engine having a catalyst converter for removing pollutants in the exhaust gas and upstream-side and downstream-side air-fuel ratio sensors disposed upstream and downstream, respectively, of the catalyst converter for detecting the concentration of a specific component in the exhaust gas. It consist of: comparing the output of the upstream-side air-fuel ratio sensor with a first predetermined reference voltage; gradually changing an air-fuel ratio correction amount in accordance with the comparison result of the output of the upstream-side air-fuel ratio sensor; skipping up the air-fuel ratio correction amount by a rich skip amount when the comparison result of the air-fuel ratio sensor is switched from the lean side to the rich side; skipping down the air-fuel correction amount by a lean skip amount when the comparison result of the air-fuel ratio sensor is switched from the rich side to the lean side; adjusting an actual air-fuel ratio in accordance with the air-fuel ratio correction amount; comparing the output of the downstream-side air-fuel ratio sensor with a second predetermined reference voltage; and changing at least one of the rich and lean skip amounts in accordance with the comparison result of the downstream-side air-fuel ratio sensor.

• Assignee: Toyota Jidosha Kabushiki Kaisha, Aichi
• Patent Number(s): US 4693076
• OSTI ID: 5908220
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
330100* -- Internal Combustion Engines
330700 -- Advanced Propulsion Systems-- Emission Control
AIR POLLUTION CONTROL
CATALYTIC CONVERTERS
COMBUSTION CONTROL
CONTROL
CORRECTIONS
DESIGN
ELECTRIC POTENTIAL
EMISSION
ENGINES
EQUIPMENT
EXHAUST GASES
FLUIDS
FUEL INJECTION SYSTEMS
FUEL SYSTEMS
FUEL-AIR RATIO
GASEOUS WASTES
GASES
HEAT ENGINES
INTERNAL COMBUSTION ENGINES
MEASURING INSTRUMENTS
METERING
METERS
OPERATION
POLLUTANTS
POLLUTION CONTROL
POLLUTION CONTROL EQUIPMENT
REMOVAL
WASTES