AIR-FUEL RATIO CONTROL DEVICE FOR INTERNAL COMBUSTION ENGINE

Title:

AIR-FUEL RATIO CONTROL DEVICE FOR INTERNAL COMBUSTION ENGINE

Document Type and Number:

WIPO Patent Application WO/1993/002281

Kind Code:

A1

Abstract:

An air-fuel ratio control device capable of preventing torque shocks liable to be produced in an engine when an air-fuel ratio is changed in order to carry out switching between rich combustion and lean combustion wherein an electronic control unit (ECU) of the device carries out, while the engine (E) is in an operating state other than a particular operating state, on-off duty control of a valve (30) disposed in a first by-pass passage (31) for by-passing a throttle valve (7) in accordance with the difference between a target air-intake volume needed to control the engine to a lean air-fuel ratio that is calculated in accordance with the opening of the throttle valve detected by means of a throttle sensor (14) and an air-intake volume detected by means of an air-flow sensor (11), while biassing a by-pass valve (42) for opening a negative pressure responsive valve (41) disposed in a second by-pass passage (43), whereby a predetermined volume of air can be supplied to the engine via the throttle valve, and the first and second by-pass passages. While the engine is in a particular operating state, an air supply through the throttle valve is permitted which is sufficient to control the engine to a rich air-fuel ratio status with an air-supply through the by-pass passages being prevented.

Inventors:

TOGAI KAZUHIDE (JP)
UEDA KATSUNORI (JP)

Application Number:

PCT/JP1992/000918

Publication Date:

February 04, 1993

Filing Date:

July 17, 1992

Export Citation:

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Assignee:

MITSUBISHI MOTORS CORP (JP)

International Classes:

F02D41/10; F02D35/00; F02D41/04; F02D41/12; F02D41/14; F02M69/32; F02B1/04; F02D9/10; (IPC1-7): F02D41/14

Foreign References:

JPS60187724A	1985-09-25
JPS6350641A	1988-03-03
JPS62218632A	1987-09-26

Other References: