Abstract: A misfire determination period is set to a predetermined range of a crank angle. A CPU performs: a calculation process of calculating an average value of a torque of an output shaft of an internal combustion engine in the misfire determination period; a misfire determining process of determining that a misfire has occurred when the calculated average value is less than a prescribed threshold value; and a process of setting the whole misfire determination period to a period in a positive torque range which is a range of a crank angle at which the torque of the output shaft is equal to or greater than zero at the time of normal combustion in which a misfire does not occur.

Abstract: A controller for a hybrid vehicle controls an electric motor such that a motor torque is input to a crankshaft in order to compensate for a decrease in an engine torque when a cylinder deactivation control is executed, the decrease resulting from suspension of combustion in one or some of cylinders. The controller calculates an engine torque calculated value using an engine rotation speed, a motor rotation speed, and the motor torque. The controller diagnoses that the cylinder deactivation control is functioning normally when the engine torque calculated value is less than a torque determination value and diagnose that the cylinder deactivation control is not functioning normally when the engine torque calculated value is not less than the torque determination value during the execution of the cylinder deactivation control.

Abstract: A CPU determines that there is a misfire when a relative magnitude of a rotation fluctuation amount ?T30[0] related to a cylinder subject to the determination in relation to a rotation fluctuation amounts ?T30[4] of the previous combustion cycle is greater than or equal to the determination value ?th. However, during the execution of a catalyst warm-up process, the CPU uses, in the comparison, the relative magnitude of the rotation fluctuation amount ?T30[0] in relation to the average ?T30ave[0] of the smallest five of the rotation fluctuation amounts ?T30[4] to ?T30[40] from the past ten combustion cycles.

Abstract: A misfire detection device includes processing circuitry configured to execute a stopping process stopping combustion control of an air-fuel mixture in one or more cylinders and a determination process determining whether a misfire has occurred based on a value of a determination subject rotation fluctuation amount, that is, a rotation fluctuation amount of a determination subject cylinder for misfire. A comparison subject rotation fluctuation amount is a rotation fluctuation amount corresponding to a crank angle separated by a predetermined angular interval from a crank angle corresponding to the determination subject rotation fluctuation amount.

Abstract: A CPU determines that misfires are occurring in a cylinder subject to determination of whether misfires are occurring when a value obtained by subtracting a rotation fluctuation amount ?T30[n?2] from a rotation fluctuation amount ?T30[n] is greater than or equal to a determination threshold. The rotation fluctuation amount ?T30[n] is subject to the misfire determination. The rotation fluctuation amount ?T30[n?2] is 360° CA earlier than the rotation fluctuation amount ?T30[n]. When stopping fuel supply to a cylinder #1 and determining whether misfires are occurring in cylinder #4, the CPU determines whether misfires are occurring after executing a correcting process that corrects the determination threshold to a second determination threshold ?th2, which is less than a first determination threshold ?th1.

Abstract: A controller for an internal combustion engine, a control method for an internal combustion engine, and a memory medium are provided. The controller executes a deactivation process that deactivates combustion control in a specified one of cylinders. A compensation process operates a power generation device that produces driving torque applied to a driven wheel so as to compensate for insufficiency of the driving torque of a vehicle caused by the deactivation process. A prohibition process prohibits the deactivation process when it is determined that compensation by a predetermined amount or larger by the compensation process cannot be performed.

Abstract: A controller for an internal combustion engine, a control method for an internal combustion engine, and a memory medium are provided. The controller determines whether an execution request of a temperature-increasing process for an aftertreatment device for exhaust gas has been issued. When the execution request is determined as having been issued, supply of fuel by a fuel injection valve corresponding to a specified cylinder is deactivated. The specified cylinder is one of cylinders. An air-fuel ratio of air-fuel mixture in a cylinder of the cylinders that differs from the specified cylinder is set to be richer than a stoichiometric air-fuel ratio. When the temperature-increasing process is executed, an adjustment device is operated so as to reduce the fuel concentration in an intake port connected to the specified cylinder.

Abstract: A CPU substitutes a difference between a crank-side speed that is a rotation speed of a crankshaft and a downstream-side speed that is a speed of a portion, opposite from the crankshaft, in a damper into a differential speed. The CPU calculates a torsion speed component that is a speed component of the crankshaft due to torsion of the damper based on a physical model of which an input is the differential speed, and calculates a time that is a variable indicating a speed of the crankshaft, used to determine a misfire, based on the torsion speed component. The CPU delays acquisition time of the downstream-side speed used to calculate the differential speed, with respect to acquisition time of the crank-side speed according to the rotation speed of the crankshaft.

Abstract: A CPU substitutes a difference between a crank-side speed that is a rotation speed of a crankshaft and a downstream-side speed that is a speed of a portion, opposite from the crankshaft, in a damper into a differential speed. The CPU calculates a torsion angle through a process of integrating the differential speed. The CPU calculates a torsion speed component that is a speed component of the crankshaft due to torsion of the damper based on a process of integrating a value obtained by multiplying the torsion angle by an elastic modulus, and calculates a time that is a variable indicating a speed of the crankshaft, used to determine a misfire, based on the torsion speed component. The CPU subtracts a value obtained by subtracting an output value of the integrating process, applied to a finite response low-pass filter process, from the output value.

Abstract: A controller of an engine performs a failure diagnosis process for an injection valve. The failure diagnosis process increases a misfire count of the engine when a variation in rotation of the engine is equal to or greater than a predetermined variation in every predetermined cycle, and determines that the injection valve has a failure when the misfire count is equal to or greater than a first predetermined number of times over a predetermined time period. The controller determines that the multi-cylinder engine is in a predetermined load operation cycle if a volume efficiency of the multi-cylinder engine is less than a reference value, and the controller determines whether continuation of the injection mode is needed based on a comparison of the misfire count and a second predetermined number of times, wherein the second predetermined number of times is less than the first predetermined number of times.

Abstract: A controller is configured to perform a control process including steps of: setting a learning execution flag to be on when a learning process has not been completed in a present trip, an engine is in a fuel cut state, and a transmission gear position is a second or lower gear position; setting the learning execution flag to be off when the transmission gear position is in a third or higher gear position; controlling to bring the engine into the fuel cut state when the engine is not in the fuel cut state, an accelerator pedal is in an accelerator off state, and the transmission gear position is the second or lower gear position; and setting the learning execution flag to be on.

Abstract: A vehicle includes an engine and an electric power output device that is configured to output electric power generated by using the engine to the outside of the vehicle. The engine includes an EGR device for recirculating exhaust gas of the engine to an intake side. The vehicle further includes a controller for controlling a recirculation amount of the exhaust gas by the EGR device in accordance with a load of the engine. The controller restricts the recirculation amount of the exhaust gas under the same load in the case where the electric power output device outputs the electric power to the outside of the vehicle in comparison with a case where the electric power output device does not output the electric power to the outside of the vehicle.

Abstract: A thermostat is diagnosed as open failure when a specified time variation in radiator inflow water temperature from a temperature sensor mounted in a first flow path running through a radiator at a time of starting an electric water pump at a cold start of an engine is equal to or greater than a predetermined variation. In the case of open failure of the thermostat, starting the electric water pump causes cooling water from a cooling water flow path of the engine to be flowed to the first flow path, as well as to a second flow path. The radiator inflow water temperature detected by the temperature sensor mounted in the first flow path is raised by the cooling water from the cooling water flow path of the warmed engine.

Abstract: An electronic control unit sets a misfire determination threshold to a first value in the cylinder injection mode, and sets the misfire determination threshold to a second value smaller than the first value in the port injection mode, and determines that a misfire occurs in the engine when a rotation fluctuation of the engine is larger than the misfire determination threshold. In a case where the cylinder injection mode is changed to the port injection mode, when a predetermined period has elapsed from the change, the electronic control unit changes the misfire determination threshold from the first value to the second value.

Abstract: A grille shutter is a device configured to adjust a temperature of coolant water of an engine by adjusting an amount of outside air introduced into a radiator of the engine. An ECU performs a failure diagnosis for the engine based on a temperature of coolant water of the engine. When the grille shutter is immovable in an opened state of the grille shutter regardless of an operating command to the grille shutter, the ECU renders the failure diagnosis process for the thermostat valve not to be executed. As a result, an incorrect operation of various controls executed based on a temperature of coolant water of the engine can be suppressed.

Abstract: At every ignition cycle, when a duration change amount ?T30[i] is equal to or less than a reference value ?T30ref2, a misfire counter Cmf is kept unchanged. When the duration change amount ?T30[i] is greater than the reference value ?T30ref2, on the other hand, the misfire counter Cmf is incremented by value 1. A misfire ratio Rmf is set to provide a smaller value when an amount increasing determination flag F[i] is equal to value 1 than a value when the amount increasing determination flag F[i] is equal to value 0. In the case where an ignition counter Ci reaches or exceeds a reference value Ciref, it is determined whether a conversion catalyst is overheated by comparison between the misfire counter Cmf and an accumulated misfire ratio Rmfsum that is an accumulated value of the misfire ratio Rmf.

Abstract: An electronic control unit sets a misfire determination threshold to a first value in the cylinder injection mode, and sets the misfire determination threshold to a second value smaller than the first value in the port injection mode, and determines that a misfire occurs in the engine when a rotation fluctuation of the engine is larger than the misfire determination threshold. In a case where the cylinder injection mode is changed to the port injection mode, when a predetermined period has elapsed from the change, the electronic control unit changes the misfire determination threshold from the first value to the second value.

Abstract: An ECU sets a leakage flow rate flowing through a radiator circulation passage in a closed state of a thermostat valve, calculates an estimated temperature of coolant water in the radiator circulation passage based on a set leakage flow rate and a detected water temperature of an engine-side coolant water temperature sensor, and performs a failure diagnosis for the thermostat valve based on a difference between the calculated estimated temperature and the detected water temperature of the radiator-side coolant water temperature sensor. The leakage flow rate during operation of the electric pump is set to be a larger value as compared to the leakage flow rate during stopping of the pump. As a result, a diagnostic can be prevented by improving an accuracy of failure detection for the thermostat valve.

Abstract: A vehicle includes an engine and an electric power output device that is configured to output electric power generated by using the engine to the outside of the vehicle. The engine includes an EGR device for recirculating exhaust gas of the engine to an intake side. The vehicle further includes a controller for controlling a recirculation amount of the exhaust gas by the EGR device in accordance with a load of the engine. The controller restricts the recirculation amount of the exhaust gas under the same load in the case where the electric power output device outputs the electric power to the outside of the vehicle in comparison with a case where the electric power output device does not output the electric power to the outside of the vehicle.

Abstract: A vehicle is disclosed which includes: an engine; a catalyst purifying exhaust gas of the engine; a grille shutter adjusting an opening area of a radiator grille; and an electronic control unit configured to: (a) control an injection quantity of fuel to be supplied to the engine, (b) detect a malfunction of the grille shutter in a state where the grille shutter is closed, and (c) increase the injection quantity when the malfunction is detected in comparison to when the malfunction is not detected.