Internal combustion engine control apparatus

Claim 2

An internal combustion engine control apparatus having an O 2 sensor for detecting O 2 concentration in exhaust gas in an exhaust system of an engine in order to perform air-fuel ratio control and an exhaust gas recirculation valve for communicating the exhaust system with an intake system in order to perform exhaust gas recirculation control, the apparatus comprising: promoting means for promoting activation of the O 2 sensor; determining means for determining whether the O 2 sensor is activated; air-fuel ratio control means for performing air-fuel ratio control in a non-feedback control mode without using feedback of O 2 concentration information during a period from start of the engine until activation of the O 2 sensor, and in a feedback control mode with feedback of O 2 concentration information in accordance with a change in the air-fuel ratio after activation of the O 2 sensor, based on a determination made by the determining means; and exhaust gas recirculation control means for performing exhaust gas recirculation control preset in accordance with switching over of the control modes of the air-fuel ratio control means, based on the determination made by the determining means.

Claim 3

An internal combustion engine control apparatus according to claim 1, wherein after activation of the O 2 sensor, the air-fuel ratio control means performs the feedback air-fuel ratio control to achieve a stoichiometric air-fuel ratio in accordance with an output from the O 2 sensor.

Claim 4

An internal combustion engine control apparatus according to claim 1, wherein the exhaust gas recirculation control means includes means for performing exhaust gas recirculation control in accordance with a predetermined air-fuel ratio change pattern during the period from start of the engine until activation of the O 2 sensor, based on determination made by the determining means.

Claim 5

An internal combustion engine control apparatus according to claim 1, wherein the exhaust gas recirculation control means comprises: coolant temperature detecting means for detecting temperature of coolant of the engine; and correcting means for, in a first case where a coolant temperature detected by the coolant temperature detecting means is higher than a first predetermined temperature and in a second case where a coolant temperature detected by the coolant temperature detecting means is lower than a second predetermined temperature, correcting exhaust gas recirculation flow by reducing the flow to a level lower than a level that occurs in a case other than the first and second cases regarding coolant temperature, based on the coolant temperature detected.

Claim 6

An internal combustion engine control apparatus having a catalyzer provided in an exhaust system of an engine for reducing a harmful exhaust gas component, an O 2 sensor for detecting O 2 concentration in exhaust gas in the exhaust system in order to perform air-fuel ratio control, and an exhaust gas recirculation valve for communicating the exhaust system with an intake system in order to perform exhaust gas recirculation control, the apparatus comprising: promoting means for promoting activation of the O 2 sensor, the O 2 sensor being a linear O 2 sensor that substantially linearly detects O 2 concentration; sensor activation determining means for determining whether the O 2 sensor is activated; catalyzer activation determining means for determining whether the catalyzer is activated; air-fuel ratio control means for performing air-fuel ratio control in a non-feedback control mode without using feedback of O 2 concentration information during a period from start of the engine until activation of the O 2 sensor, in a feedback control mode with feedback of O 2 concentration information to maintain the air-fuel ratio to a fuel-lean side in accordance with a change in the air-fuel ratio during a period after activation of the O 2 sensor until activation of the catalyzer, and in another feedback control mode with feedback of O 2 concentration information to achieve a stoichiometric air-fuel ratio in accordance with a change in the air-fuel ratio after activation of the catalyzer, based on determination made by the sensor activation determining means and the catalyzer activation determining means; and exhaust gas recirculation control means for performing exhaust gas recirculation control in accordance with switching over of control modes of the air-fuel ratio control means, based on determination made by the sensor activation determining means and the catalyzer activation determining means.

Claim 7

An internal combustion engine control apparatus having a catalyzer provided in an exhaust system of an engine for reducing a harmful exhaust gas component, an O 2 sensor for detecting O 2 concentration in exhaust gas in the exhaust system in order to perform air-fuel ratio control, and an exhaust gas recirculation valve for communicating the exhaust system with an intake system in order to perform exhaust gas recirculation control, the apparatus comprising: promoting means for promoting activation of the O 2 sensor, the O 2 sensor being a linear O 2 sensor that substantially linearly detects O 2 concentration; sensor activation determining means for determining whether the O 2 sensor is activated; catalyzer activation determining means for determining whether the catalyzer is activated; air-fuel ratio control means for performing air-fuel ratio control in a non-feedback control mode without using feedback of O 2 concentration information during a period from start of the engine until activation of the O 2 sensor, in a feedback control mode with feedback of O 2 concentration information to maintain the air-fuel ratio to a fuel-lean side in accordance with a change in the air-fuel ratio during a period after activation of the O 2 sensor until activation of the catalyzer, and in another feedback control mode with feedback of O 2 concentration information to achieve a stoichiometric air-fuel ratio in accordance with a change in the air-fuel ratio after activation of the catalyzer, based on determination made by the sensor activation determining means and the catalyzer activation determining means; and exhaust gas recirculation control means for performing exhaust gas recirculation control in accordance with switching over of control modes of the air-fuel ratio control means, based on determination made by the sensor activation determining means and the catalyzer activation determining means.

Claim 8

An internal combustion engine control apparatus according to claim 5, wherein the exhaust gas recirculation control means includes means for performing exhaust gas recirculation control in accordance with a predetermined air-fuel ratio change pattern during the period from start of the engine until activation of the O 2 sensor, based on determination made by the determining means.

Claim 9

An internal combustion engine control apparatus according to claim 5, wherein the exhaust gas recirculation control means comprises: coolant temperature detecting means for detecting temperature of coolant of the engine; and correcting means for, in a first case where a coolant temperature detected by the coolant temperature detecting means is higher than a first predetermined temperature and in a second case where a coolant temperature detected by the coolant temperature detecting means is lower than a second predetermined temperature, correcting exhaust gas recirculation flow by reducing the flow to a level lower than a level that occurs in a case other than the first and second cases regarding coolant temperature, based on the coolant temperature detected.

Claim 10

An internal combustion engine control apparatus having an O 2 sensor for detecting O 2 concentration in exhaust gas in an exhaust system of an engine, the apparatus comprising: determining means for determining whether the O 2 sensor is activated; and exhaust gas recirculation control means for performing exhaust gas recirculation control in accordance with a predetermined air-fuel ratio change pattern during a period from start of the engine until activation of the O 2 sensor, based on determination made by the determining means.

Claim 11

An internal combustion engine control apparatus having an O 2 sensor for detecting O 2 concentration in exhaust gas in an exhaust system of an engine, the apparatus comprising: determining means for determining whether the O 2 sensor is activated; and exhaust gas recirculation control means for performing exhaust gas recirculation control in accordance with a predetermined air-fuel ratio change pattern during a period from start of the engine until activation of the O 2 sensor, based on determination made by the determining means.

Claim 12

An internal combustion engine control apparatus according to claim 8, wherein the exhaust gas recirculation control means comprises: coolant temperature detecting means for detecting temperature of coolant of the engine; and correcting means for, in a first case where a coolant temperature detected by the coolant temperature detecting means is higher than a first predetermined temperature and in a second case where a coolant temperature detected by the coolant temperature detecting means is lower than a second predetermined temperature, correcting exhaust gas recirculation flow by reducing the flow to a level lower than a level that occurs in a case other than the first and second cases regarding coolant temperature, based on the coolant temperature detected.