An engine control device includes a processor configured to execute a fuel injection control including: a first fuel injection processing for injecting an amount of fuel according to a first intake air amount based on an intake air flow rate detected by an air flow sensor; and a second fuel injection processing for injecting an amount of fuel according to a second intake air amount based on a throttle opening degree detected by a throttle position sensor. The processor selects the first fuel injection processing when a pulsation rate of the intake air flow rate is equal to or lower than a pulsation rate threshold value, and selects the second fuel injection processing when the pulsation rate is higher than the pulsation rate threshold value. The pulsation rate threshold value is smaller when a temperature correlation value is low than when the temperature correlation value is high.

A method of determining an air volume in an active purge system may include checking whether an engine operates in an idle state; determining an air volume reaching a combustion chamber of the engine in response to a signal received from a sensor provided in an intake pipe; checking whether an evaporation gas collected in a canister is introduced into the intake pipe; estimating an amount of the evaporation gas introduced into the intake pipe and primarily correcting the air volume determined according to the estimated amount of the evaporation gas; checking whether an opening holding time of an intake valve in the engine is varied due to an operation of a continuously variable valve duration (CVVD) system electrically connected to the controller; and deriving a correction variable by substituting an operation duty of the CVVD system into a formula, a table, or a map provided in advance, and secondarily correcting the primarily corrected air volume according to the correction variable.

An engine includes a first injection valve, which is one of port and direct injection valves, and a second injection valve, which is the other. When operating only the first injection valve based on a base injection amount, which has been corrected using a feedback operation amount and a first learning value, an air-fuel ratio control apparatus updates the first learning value and determines that the first learning value has converged on condition that a correction ratio of the base injection amount is not more than a predetermined ratio. When the first and second injection valves are being operated, the apparatus updates a second learning value for the second injection valve on condition that the first learning value has converged and the ratio of the injection amount of the second injection valve is not less than a specified value.

An engine controller is provided. A second calculation process calculates an intake air amount without using an output of an air flow meter. A second determination process determines whether an intake air pulsation in an intake passage is great without using the output of the air flow meter. When the intake air pulsation is determined to be great by at least one of a first determination process and the second determination process, a calculation method switching process selects the calculated value of the intake air amount obtained by the second calculation process as a calculated value of the intake air amount used to determine an operation amount of an actuator.

The fuel injection control device and fuel injection control method according to the present invention allow a fuel injection device to perform fuel injection in the case where an open period of the intake valve and an open period of the exhaust valve overlap with each other, and sets the timing to start injection to the closing timing of the exhaust valve, and that sets the timing to end injection to the timing at which a deceleration rate of intake air speed becomes the local maximum. As such, the homogeneity of in-cylinder air-fuel mixture can be improved while preventing the adhesion of fuel to the inner wall of the intake port and the blow-through of fuel to the exhaust passage from occurring.

An engine control apparatus includes first and second fuel injection amount calculators, a fuel injection controller, an EGR valve controller, and an EGR valve diagnosis unit. The first and second fuel injection amount calculators are configured to calculate first and second fuel injection amounts on the basis of a detected intake air amount and detected pressure in an intake pipe, respectively. The fuel injection controller is configured to control a fuel injection apparatus for an engine on the basis of a correction fuel injection amount that is a result of addition of the first and second fuel injection amounts respectively multiplied by first and second weight coefficients. When the fuel injection is restarted after diagnosis of the EGR valve carried out by the EGR valve diagnosis unit, the fuel injection controller increases the second weight coefficient, and thereafter gradually increases and reduces the first and second weight coefficients, respectively.

A first intake air amount an engine is calculated based on a detected value of an intake air flow rate of an air flowmeter. A second intake air amount is calculated based on any one of a detected value of an intake pipe pressure and a throttle opening degree instead of the detected value of the intake air flow rate. When it is determined that the intake pulsation is not large, a difference amount of the second intake air amount from the first intake air amount is calculated. A corrected second intake air amount, which is a sum of the second intake air amount and the difference amount, is set as an intake air amount calculated value when it is determined that the intake pulsation is large.

An engine controller, an engine control method, and memory medium are provided. A second calculation process calculates an intake air amount without using a detection result of an air flow meter. The determination process determines that intake air pulsation is great if it is confirmed that a difference between an average flow rate and a minimum flow rate is great. The average flow rate is an average value of an intake air flow rate within a period of the intake air pulsation. The minimum flow rate is a minimum value of the intake air flow rate within the period. When it is determined that the intake air pulsation is great, a calculation method switching process selects a calculated value of the intake air amount that is obtained by the second calculation process.

An internal combustion engine control device includes a combustion degree of stoppage determination unit which determines whether stoppage of combustion of an internal combustion engine has reached a threshold degree, and an internal combustion engine control unit which performs a normal control in the case that the combustion of the engine is resumed in a state where stoppage of combustion has not reached the threshold degree, and performs a soot suppression control in the case that the engine combustion is resumed in a state where stoppage of combustion has reached the threshold degree. In the soot suppression control, the split injection or the single injection is carried out within the predetermined stroke, and the engine control unit causes a fuel injection timing in the single injection of the soot suppression control to be delayed with respect to the fuel injection timing in the single injection of the normal control.

A multi-injection process includes performing intake synchronized injection in which fuel is injected in synchronism with an open valve period of an intake valve, and an intake asynchronous injection in which fuel is injected at a more advanced timing than during intake synchronized injection. A single-injection process includes injecting a required injection amount of fuel by intake asynchronous injection. An operating process includes operating a port injection valve for injecting fuel into an intake passageway. A selection process includes selecting the single-injection process if the temperature of an intake system of an internal combustion engine is not lower than a prescribed temperature, and selecting the multi-injection process if the temperature of the intake system is less than the prescribed temperature.