Air-fuel ratio control system for an internal combustion engine

Patent · Tue Jun 05 04:00:00 EDT 1984

OSTI ID:6465837

Ohara, Y; Yabuhara, H

An air-fuel ratio control system for a vehicle powered by an internal combustion engine having an emission control system with a three-way catalytic converter for controlling the air-fuel ratio in accordance with the operation of the engine. A vacuum sensor detects heavy load operation of the engine, and an engine speed detecting circuit and a predetermined voltage supply circuit are provided. The engine speed detecting circuit is so arranged as to produce an output when the engine speed is lower than a predetermined value. A feedback control circuit is provided for controlling the air-fuel ratio to the stoichiometric air-fuel ratio in normal operating conditions. A first switch device is actuated by the output of the vacuum sensor to connect the output of the predetermined voltage supply circuit with the input of the feedback control circuit when heavy load operation is detected and to render the feedback control circuit inoperative. A second switch is to be actuated by the output of the engine speed detecting circuit to stop the control of the air-fuel ratio for supplying a rich air-fuel mixture by the carburetor to the engine.

• Assignee: Fuji Jukogyo Kabushiki Kaisha (Japan); Nissan Motor Co., Ltd. (Japan)
• Patent Number(s): US 4452209
• OSTI ID: 6465837
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
330100* -- Internal Combustion Engines
CARBURETORS
CATALYTIC CONVERTERS
CONTROL SYSTEMS
DESIGN
ELECTRONIC CIRCUITS
ENGINES
EQUIPMENT
FEEDBACK
FUEL SYSTEMS
FUEL-AIR RATIO
HEAT ENGINES
INTERNAL COMBUSTION ENGINES
POLLUTION CONTROL EQUIPMENT