US 4,732,130 A · Apparatus for controlling air-fuel ratio for internal combustion engine

Abstract

An apparatus for controlling an air-fuel ratio for an internal combustion engine in which the air-fuel ratio is controlled to the leaner side of a stoichiometric air-fuel ratio in a normal operating condition. As the speed reduction ratio decreases, the air-fuel ratio is controlled so as to become increasingly leaner than the stoichiometric air-fuel ratio. Thus, when the speed reduction ratio is relatively large, the air-fuel ratio is controlled so as to be richer than a critical air-fuel ratio concerning misfire, thereby preventing occurrence of a surge in the engine output which would otherwise be caused by a change in combustion state. When the speed reduction ratio is relatively small, the air-fuel ratio is made to approach said critical air-fuel ratio in order to decrease the rate of fuel consumption.

Claims12

Dependent claims

An apparatus for controlling an air-fuel ratio for an internal combustion engine, comprising:

calculating means for calculating a basic fuel injection quantity on the basis of an engine load and a rotational speed of said engine;
operating condition detecting means for detecting an operating condition of said engine;
speed reduction ratio detecting means for detecting a speed reduction ratio set in a transmission;
and
control means which controls, when a predetermined operating condition is detected, the air-fuel ratio so as to be leaner than a stoichiometric air-fuel ratio on the basis of said basic fuel unjection quantity in such a manner that the air-fuel ratio is made progressively leaner than the stoichiometric air-fuel as the speed reduction ratio becomes smaller.

2 more elements

An apparatus for controlling an air-fuel ratio for an internal combustion engine, comprising:

load detecting means for detecting an engine load;
engine speed detecting means for detecting a rotational speed of said engine;
throttle position detecting means for detecting whether or not a throttle valve is in a region between a full-closing position and a full-open position, said region excluding these two positions;
cooling water temperature detecting means for detecting the temperature of water for cooling said engine:
vehicle speed detecting means for detecting a vehicle speed;
memory means for storing a lean correction coefficient which decreases as the rotational speed of said engine increases;
speed reduction ratio detecting means for detecting a speed reduction ratio set in a transmission on the basis of the vehicle speed and the rotational speed of said engine;
calculating means for calculating a basic fuel injection quantity on the basis of the engine load and the rotational speed of said engine;
and
control means which is activated when the following set of conditions is met, that is, said throttle valve is detected being in said region, the cooling water temperature is detected being higher than a predetermined value, and a speed reduction ratio is detected which is exclusive of a speed reduction ratio corresponding to a 1st speed gear position, so as to calculate a lean correction coefficient corresponding to a present engine speed on the basis of the contents stored in said memory means and control the air-fuel ratio so as to be leaner than a stoichiometric air-fuel ratio on the basis of said basic fuel injection quantity and the calculated lean correction coefficient.

7 more elements

Dependencies are inferred from the claim text.

Apparatus for controlling air-fuel ratio for internal combustion engine

Life of this patent

Apparatus for controlling air-fuel ratio for internal combustion engine

Life of this patent

Abstract

Claims12