Air-fuel ratio controller of IC engine

Abstract

Provided is an air / fuel ratio control device for an internal combustion engine. When the internal combustion engine is detected to be in a cooled condition, it is operated so that a plurality of predetermined cylinders of all cylinders have an air / fuel ratio to be a stoichiometric approach value while one or more predetermined cylinders other than the plurality of predetermined cylinders have an air / fuel ratio to be a preset rate closer to a lean air-fuel ratio than to the stoichiometric approach value (the stoichiometric approach value*a lean coefficient A in an optimum region).

Description

technical field [0001] The invention relates to an air-fuel ratio control device of an internal combustion engine, in detail, relates to an air-fuel ratio control technology when the internal combustion engine is in a cold state. Background technique [0002] When the internal combustion engine (engine) is in a cold state (cold state), since the catalytic converter and the air-fuel ratio sensor installed in the exhaust system are often not in an active state, there is the following problem: the exhaust gas cannot be fully purified by the catalytic converter. HC (hydrocarbon) and CO (carbon monoxide) in the exhaust gas from the engine, or the air-fuel ratio cannot be properly feedback controlled. [0003] Therefore, for the purpose of reducing HC and CO, it is effective to set the air-fuel ratio closer to the leaner air-fuel ratio than the stoichiometric air-fuel ratio when the engine is cold. In this way, by setting the air-fuel ratio close t...

AI Technical Summary

Problems solved by technology

[0002] When the internal combustion engine (engine) is in a cold state (cold state), since the catalytic converter and the air-fuel ratio sensor installed in the exhaust system are often not in an active state, there is the following problem: the exhaust gas cannot be fully purified by the catalytic converter. HC (hydrocarbons) and CO (carbon monoxide) in the exhaust from the engine, or failure to properly feedback control the air-fuel ratio

[0009] However, if the air-fuel ratio distribution among cylinders is poor, correction control must be performed for each cylinder to make the air-fuel ratio distribution uniform, or the manufacturing accuracy must be improved, which complicates control and increases man-hours for production management, which is not desirable.

[0010] In addition, for the change of fuel injection amount, it is only necessary to correct the air-fuel ratio for each cylinder, but this leads to complicated control, and such correction is difficult in reality

[0011] In addition, for changes in fuel properties, there is a problem that the detection of fuel properties requires high precision and reliability

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