Air-to-fuel ratio control apparatus for an internal combustion engine

Claim 2

An air-to-fuel ratio control apparatus for an internal combustion engine provided with an air-to-fuel ratio sensor which detects an air-to-fuel ratio of an air-to-fuel mixture from a condition of an exhaust gas originating from the air-fuel mixture, the air-fuel ratio control apparatus comprising: air-to-fuel ratio controlling means for performing feedback control in response to an output signal of the air-to-fuel ratio sensor so that the detected air-to-fuel ratio will be substantially egual to a target air-to-fuel ratio; and gain setting means for setting a feedback gain of the feedback control performed by the air-to-fuel ratio controlling means in response to an atmospheric pressure, wherein the air-to-fuel ratio controlling means comprises: means for suspending the feedback control and performing prospective control in cases where given engine operating conditions continue for at least a given time interval.

Claim 3

An air-to-fuel ratio control apparatus as recited in claim 1, wherein the given engine operating conditions include conditions in which an integration value of a value calculated based on a degree of richness of the air-fuel mixture and a flow rate of the exhaust gas is equal to at least a given value.

Claim 4

An air-to-fuel ratio control apparatus for an internal combustion engine provided with an air-to-fuel ratio sensor which detects an air-to-fuel ratio of an air-to-fuel mixture from a condition of an exhaust gas originating from the air-fuel mixture, the air-fuel ratio control apparatus comprising: air-to-fuel ratio controlling means for performing feedback control in response to an output signal of the air-to-fuel ratio sensor so that the detected air-to-fuel ratio will be substantially egual to a target air-to-fuel ratio; and gain setting means for setting a feedback gain of the feedback control performed by the air-to-fuel ratio controlling means in response to an atmospheric pressure, wherein the air-to-fuel ratio controlling means comprises: means for, under engine operating conditions in which a temperature of a catalyst for cleaning the exhaust gas becomes high, varying the target air-to-fuel ratio during the feedback control by the air-to-fuel ratio controlling means in accordance with a time elapsed from a starting moment of the engine operating conditions.

Claim 5

An air-to-fuel ratio control apparatus for an internal combustion engine provided with an air-to-fuel ratio sensor which detects an air-to-fuel ratio of an air-to-fuel mixture from a condition of an exhaust gas originating from the air-fuel mixture, the air-fuel ratio control apparatus comprising: air-to-fuel ratio controlling means for performing feedback control in response to an output signal of the air-to-fuel ratio sensor so that the detected air-to-fuel ratio will be substantially egual to a target air-to-fuel ratio; and gain setting means for setting a feedback gain of the feedback control performed by the air-to-fuel ratio controlling means in response to an atmospheric pressure, wherein the air-to-fuel ratio controlling means comprises: means for, under engine operating conditions in which a temperature of a catalyst for cleaning the exhaust gas becomes high, varying the target air-to-fuel ratio during the feedback control by the air-to-fuel ratio controlling means in accordance with a time elapsed from a starting moment of the engine operating conditions.

Claim 6

An air-to-fuel ratio controlling apparatus for an internal combustion engine, comprising: an air-to-fuel ratio sensor for detecting an air-to-fuel ratio of an air-fuel mixture from a condition of an exhaust gas originating from the air-fuel mixture; air-to-fuel ratio feedback controlling means for performing feedback control in response to an output signal of the air-to-fuel ratio sensor so that the detected air-to-fuel ratio will be substantially equal to a target air-to-fuel ratio; prospective control means for predicting an air-to-fuel ratio of the air-fuel mixture and performing prospective control to control an actual air-to-fuel ratio in response to the predicted air-to-fuel ratio; and air-to-fuel ratio controlling means for deciding whether the output signal of the air-to-fuel ratio sensor is outside a predetermined range, and implementing a change from the feedback control to the prospective control when the air-to-fuel ratio controlling means decides that the output signal of the air-to-fuel ratio sensor is outside the predetermined range.

Claim 7

An air-to-fuel ratio controlling apparatus for an internal combustion engine, comprising: an air-to-fuel ratio sensor for detecting an air-to-fuel ratio of an air-fuel mixture from a condition of an exhaust gas originating from the air-fuel mixture; air-to-fuel ratio feedback controlling means for performing feedback control in response to an output signal of the air-to-fuel ratio sensor so that the detected air-to-fuel ratio will be substantially equal to a target air-to-fuel ratio; prospective control means for predicting an air-to-fuel ratio of the air-fuel mixture and performing prospective control to control an actual air-to-fuel ratio in response to the predicted air-to-fuel ratio; and air-to-fuel ratio controlling means for deciding whether the output signal of the air-to-fuel ratio sensor is outside a predetermined range, and implementing a change from the feedback control to the prospective control when the air-to-fuel ratio controlling means decides that the output signal of the air-to-fuel ratio sensor is outside the predetermined range.

Claim 8

An air-to-fuel ratio control apparatus for an internal combustion engine, comprising: an air-to-fuel ratio sensor for detecting an air-to-fuel ratio of an air-fuel mixture from a condition of an exhaust gas originating from the air-fuel mixture; air-to-fuel ratio feedback controlling means for performing feedback control in response to an output signal of the air-to-fuel ratio sensor so that the detected air-to-fuel ratio will be substantially egual to a target air-to-fuel ratio; prospective control means for predicting an air-to-fuel ratio of the air-fuel mixture and performing prospective control to control an actual air-to-fuel ratio in response to the predicted air-to-fuel ratio; and air-to-fuel ratio controlling means for implementing a change between the feedback control and the prospective control in response to operating conditions of the engine, wherein the air-to-fuel ratio controlling means is operative for selecting the prospective control during the operating conditions of the engine in which an integration value of a value calculated based on a degree of richness of the air-fuel mixture and a flow rate of the exhaust gas is equal to at least a given value.

Claim 9

An air-to-fuel ratio control apparatus for an internal combustion engine, comprising: an air-to-fuel ratio sensor for detecting an air-to-fuel ratio of an air-fuel mixture from a condition of an exhaust gas originating from the air-fuel mixture; air-to-fuel ratio feedback controlling means for performing feedback control in response to an output signal of the air-to-fuel ratio sensor so that the detected air-to-fuel ratio will be substantially egual to a target air-to-fuel ratio; prospective control means for predicting an air-to-fuel ratio of the air-fuel mixture and performing prospective control to control an actual air-to-fuel ratio in response to the predicted air-to-fuel ratio; and air-to-fuel ratio controlling means for implementing a change between the feedback control and the prospective control in response to operating conditions of the engine, wherein the air-to-fuel ratio controlling means is operative for selecting the prospective control during the operating conditions of the engine in which an integration value of a value calculated based on a degree of richness of the air-fuel mixture and a flow rate of the exhaust gas is equal to at least a given value.

Claim 10

An air-to-fuel ratio controlling apparatus for an internal combustion engine, comprising: an air-to-fuel ratio sensor for detecting an air-to-fuel ratio of an air-fuel mixture from a condition of an exhaust gas originating from the air-fuel mixture; air-to-fuel ratio feedback controlling means for performing feedback control in response to an output signal of the air-to-fuel ratio sensor so that the detected air-to-fuel ratio will be substantially egual to a target air-to-fuel ratio; prospective control means for predicting an air-to-fuel ratio of the air-fuel mixture and performing prospective control to control an actual air-to-fuel ratio in response to the predicted air-to-fuel ratio; and air-to-fuel ratio controlling means for implementing a change between the feedback control and the prospective control in response to operating conditions of the engine, wherein the air-to-fuel ratio feedback controlling means comprises means for, under engine operating conditions in which a temperature of a catalyst for cleaning the exhaust gas becomes high, varying the target air-to-fuel ratio during the feedback control by the air-to fuel ratio feedback controlling means in accordance with a time elapsed from a starting moment of the engine operating conditions.

Claim 11

An air-to-fuel ratio controlling apparatus for an internal combustion engine, comprising: an air-to-fuel ratio sensor for detecting an air-to-fuel ratio of an air-fuel mixture from a condition of an exhaust gas originating from the air-fuel mixture; air-to-fuel ratio feedback controlling means for performing feedback control in response to an output signal of the air-to-fuel ratio sensor so that the detected air-to-fuel ratio will be substantially egual to a target air-to-fuel ratio; prospective control means for predicting an air-to-fuel ratio of the air-fuel mixture and performing prospective control to control an actual air-to-fuel ratio in response to the predicted air-to-fuel ratio; and air-to-fuel ratio controlling means for implementing a change between the feedback control and the prospective control in response to operating conditions of the engine, wherein the air-to-fuel ratio feedback controlling means comprises means for, under engine operating conditions in which a temperature of a catalyst for cleaning the exhaust gas becomes high, varying the target air-to-fuel ratio during the feedback control by the air-to fuel ratio feedback controlling means in accordance with a time elapsed from a starting moment of the engine operating conditions.

Claim 12

An air-to-fuel ratio controlling apparatus for an internal combustion engine, comprising: an air-to-fuel ratio sensor for detecting an air-to-fuel ratio of an air-fuel mixture from a condition of an exhaust gas originating from the air-fuel mixture; air-to-fuel ratio feedback controlling means for performing feedback control in response to an output signal of the air-to-fuel ratio sensor so that the detected air-to-fuel ratio will be substantially equal to a target air-to-fuel ratio; prospective control means for predicting an air-to-fuel ratio of the air-fuel mixture and performing prospective control to control an actual air-to-fuel ratio in response to the predicted air-to-fuel ratio; and air-to-fuel ratio controlling means for deciding whether the output signal of the air-to-fuel ratio sensor remains outside a predetermined range during at least a given time interval, and for implementing a change from the feedback control to the prospective control when the air-to-fuel-ratio controlling means decides that the output signal of the air-to-fuel ratio sensor remains outside the predetermined range during the at least given time interval.

Claim 13

An air-to-fuel ratio controlling apparatus for an internal combustion engine, comprising: an air-to-fuel ratio sensor for detecting an air-to-fuel ratio of an air-fuel mixture from a condition of an exhaust gas originating from the air-fuel mixture; air-to-fuel ratio feedback controlling means for performing feedback control in response to an output signal of the air-to-fuel ratio sensor so that the detected air-to-fuel ratio will be substantially equal to a target air-to-fuel ratio; prospective control means for predicting an air-to-fuel ratio of the air-fuel mixture and performing prospective control to control an actual air-to-fuel ratio in response to the predicted air-to-fuel ratio; and air-to-fuel ratio controlling means for deciding whether the output signal of the air-to-fuel ratio sensor remains outside a predetermined range during at least a given time interval, and for implementing a change from the feedback control to the prospective control when the air-to-fuel-ratio controlling means decides that the output signal of the air-to-fuel ratio sensor remains outside the predetermined range during the at least given time interval.