Abstract: An air-fuel ratio control device of an internal combustion engine is provided. The control device includes a learning section, a correction section, and an inhibiting section. When an execution condition is met, the learning section learns, as a deviation amount learned value, a constant deviation amount between a correction amount and its reference value in different manners between a case in which the lift amount of the intake valve is in a first lift amount region used only when the execution condition is not met and a case in which the lift amount is in a second lift amount region used only when the execution condition is met. The learning section computes and stores the relationship between the deviation amount and the lift amount based on the deviation amount learned value. A correction section computes the deviation amount correction value from the stored relationship based on the lift amount, and corrects the fuel injection amount command value using the deviation amount correction value.

Abstract: An air-fuel ratio control apparatus includes a learning unit learning amounts of divergence of a correction amount from a reference value thereof respectively as to a plurality of set lift amount regions as divergence amount learning values, a correction unit calculating a divergence amount correction value and correcting a fuel injection amount command value, and a reflection unit reflecting a learning result of the divergence amount learning value of a specific one of the plurality of the set lift amount regions on the divergence amount learning value of another one of the lift amount regions when there is a history indicating that the divergence amount learning value of the specific one of the lift amount regions has been learned and there is no history indicating that the divergence amount learning value of that another one of the lift amount regions has been learned.

Abstract: An air-fuel ratio control apparatus includes a learning unit learning amounts of divergence of a correction amount from a reference value thereof respectively as to a plurality of set lift amount regions as divergence amount learning values, a correction unit calculating a divergence amount correction value and correcting a fuel injection amount command value, and a reflection unit reflecting a learning result of the divergence amount learning value of a specific one of the plurality of the set lift amount regions on the divergence amount learning value of another one of the lift amount regions when there is a history indicating that the divergence amount learning value of the specific one of the lift amount regions has been learned and there is no history indicating that the divergence amount learning value of that another one of the lift amount regions has been learned.

Abstract: An air-fuel ratio control device of an internal combustion engine is provided. The control device includes a learning section, a correction section, and an inhibiting section. When an execution condition is met, the learning section learns, as a deviation amount learned value, a constant deviation amount between a correction amount and its reference value in different manners between a case in which the lift amount of the intake valve is in a first lift amount region used only when the execution condition is not met and a case in which the lift amount is in a second lift amount region used only when the execution condition is met. The learning section computes and stores the relationship between the deviation amount and the lift amount based on the deviation amount learned value. A correction section computes the deviation amount correction value from the stored relationship based on the lift amount, and corrects the fuel injection amount command value using the deviation amount correction value.

Abstract: An engine ECU executes a program including the step of detecting an engine coolant temperature (THW), the step of selecting a map for a warm state as the map for calculating a fuel injection ratio (or a DI ratio) (r) when the engine coolant temperature (THW) is equal to or higher than a temperature threshold value (THW(TH)), the step of selecting a map for a cold state as the map for calculating the fuel injection ratio (or the DI ratio) (r) when the engine coolant temperature (THW) is lower than the temperature threshold value (THW(TH)), and the step of calculating the fuel injection ratio between the in-cylinder injector and the-intake manifold injector (or the DI ratio) (r) based on the engine speed, load factor, and the selected map.

Abstract: An engine ECU executes a program including the step of detecting an engine coolant temperature (THW), the step of selecting a map for a warm state as the map for calculating a fuel injection ratio (or a DI ratio) (r) when the engine coolant temperature (THW) is equal to or higher than a temperature threshold value (THW(TH)), the step of selecting a map for a cold state as the map for calculating the fuel injection ratio (or the DI ratio) (r) when the engine coolant temperature (THW) is lower than the temperature threshold value (THW(TH)), and the step of calculating the fuel injection ratio between the in-cylinder injector and the-intake manifold injector (or the DI ratio) (r) based on the engine speed, load factor, and the selected map.

Abstract: In air-fuel ratio feedback control, a rich skip amount is made larger than a lean skip amount by an offset amount OS such that a feedback control center is offset to the rich side. As a result, the amount of error from an erroneous detection by an O2 sensor is absorbed and deterioration of gas emissions in a multiple-injection mode is minimized.

Abstract: It is highly likely that fuel is already adhered to the inside wall surface of the combustion chamber at the beginning of engine startup when it is estimated that the temperature at the beginning of engine stop of the most recent engine operation is low when the engine is restarted. Under these conditions, a fuel injection quantity is reduced or an intake air quantity is increased when the engine is restarted. Therefore, even if the adhered fuel vaporizes when the engine is restarted, the air-fuel ratio will not become excessively rich as a result.

Abstract: In air-fuel ratio feedback control, a rich skip amount is made larger than a lean skip amount by an offset amount OS such that a feedback control center is offset to the rich side. As a result, the amount of error from an erroneous detection by an O2 sensor is absorbed and deterioration of gas emissions in a multiple-injection mode is minimized.

Abstract: It is highly likely that fuel is already adhered to the inside wall surface of the combustion chamber at the beginning of engine startup when it is estimated that the temperature at the beginning of engine stop of the most recent engine operation is low when the engine is restarted. Under these conditions, a fuel injection quantity is reduced or an intake air quantity is increased when the engine is restarted. Therefore, even if the adhered fuel vaporizes when the engine is restarted, the air-fuel ratio will not become excessively rich as a result.

Abstract: A diesel engine has a fuel injection nozzle to which pressurized fuel is supplied from a pump. The nozzle has a pressure sensor detecting the fuel pressure and a lift sensor sensing a lift magnitude of a needle valve. An electronic control unit (ECU) computes a variation ratio of the fuel pressure value which is measured by the pressure sensor. The ECU computes a non-increasing point in an increasing part of variation ratio and judges the point to be a timing for starting the fuel injection of the nozzle. The EPU also computes the actual fuel injection amount in accordance with the fuel injection timing as well as the fuel pressure and the lift amount of the needle valve both at the various points. The EPU controls the actual injection amount to be identical to a target fuel injection amount.

Abstract: A diesel engine has a fuel injection nozzle to which pressurized fuel is supplied from a pump. The nozzle has a pressure sensor detecting the fuel pressure and a lift sensor sensing a lift magnitude of a needle valve. An electronic control unit (ECU) computes a variation ratio of the fuel pressure value which is measured by the pressure sensor. The ECU computes a non-increasing point in an increasing part of variation ratio and judges the point to be a timing for starting the fuel injection of the nozzle. The ECU also computes the actual fuel injection amount in accordance with the fuel injection timing as well as the fuel pressure and the lift amount of the needle valve both at the various points. The ECU controls the actual injection amount to be identical to a target fuel injection amount.

Abstract: A control device of an engine having cylinders which are divided into two cylinder groups. The first cylinder group is provided with a first throttle valve and a first recirculation valve. The second cylinder group is provided with a second throttle valve and a second recirculation valve. When shifting from full cylinder operation to partial cylinder operation where the second cylinder group is left idle, the sum of the load of both the cylinder groups is maintained as substantially the same load as the total load before shifting to the partial cylinder operation, the first throttle valve is gradually opened, and the second throttle valve is gradually closed.

Abstract: A diesel engine has a fuel injection nozzle to which pressurized fuel is supplied from a pump. The nozzle has a pressure sensor detecting the fuel pressure and a lift sensor sensing a lift magnitude of a needle valve. An electronic control unit (ECU) computes a variation ratio of the fuel pressure value which is measured by the pressure sensor. The ECU computes a non-increasing point in an increasing part of variation ratio and judge the point to be a timing for starting the fuel injection of the nozzle. The EPU also computes the actual fuel injection amount in accordance with the fuel injection timing as well as the fuel pressure and the lift amount of the needle valve both at the various points. The EPU control the actual injection amount to be identical to a target fuel injection amount.