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: In an in-cylinder injection mode, a misfire count M is incremented by value 1 when a time variation ?T30[i] with regard to a cylinder [i] is not less than a reference value ?T30ref in each ignition cycle. When a number of operations N becomes equal to or greater than a reference value Nref, the misfire count M is compared with a reference value Mref1. When the misfire count M is equal to or greater than the reference value Mref1, it is determined that an in-cylinder injector has a failure. When the misfire count M is less than the reference value Mref1, on the other hand, a likelihood that the in-cylinder injection mode is likely to be continued is increased at a large value (L/N), compared with the likelihood at a small value (L/N).

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.

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: When a rotational fluctuation ?NEeng of an engine is equal to or larger than a first threshold NEref1, a rotational fluctuation ?NEmg1 of a motor MG1 that is calculated at a timing preceding the rotational fluctuation ?NEeng of the engine by 180 degrees in terms of a rotational angle of a crankshaft is compared with a second threshold NEref2. When the rotational fluctuation ?NEmg1 is equal to or larger than the second threshold NEref2, it is determined that the rotational fluctuation ?NEeng of the engine has reached a value equal to or larger than a threshold NEref due to a disturbance such as running on a bad road or the like, and a misfire counter is maintained. When the rotational fluctuation ?NEmg1 is smaller than the second threshold NEref2, it is determined that a misfire may be occurring in at least one of cylinders of the engine, and the misfire counter is incremented.

Abstract: A learning unit learns a difference between a detected value ECT and a detected value RCT when it is determined that the detected value ECT and detected value RCT are stable while an engine is at a stop. A diagnostic unit performs a fault diagnosis for the engine based on the difference between the detected value ECT and detected value RCT having been corrected through use of a learned value learned by the learning unit. Accordingly, a fault diagnostic system for an internal combustion engine and a fault diagnostic method for an internal combustion engine can be achieved in which accuracy in fault diagnosis for the internal combustion engine can be improved and an erroneous diagnosis can be restrained.

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: When a rotational fluctuation ?NEeng of an engine is equal to or larger than a first threshold NEref1, a rotational fluctuation ?NEmg1 of a motor MG1 that is calculated at a timing preceding the rotational fluctuation ?NEeng of the engine by 180 degrees in terms of a rotational angle of a crankshaft is compared with a second threshold NEref2. When the rotational fluctuation ?NEmg1 is equal to or larger than the second threshold NEref2, it is determined that the rotational fluctuation ?NEeng of the engine has reached a value equal to or larger than a threshold NEref due to a disturbance such as running on a bad road or the like, and a misfire counter is maintained. When the rotational fluctuation ?NEmg1 is smaller than the second threshold NEref2, it is determined that a misfire may be occurring in at least one of cylinders of the engine, and the misfire counter is incremented.

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.

Abstract: A vehicle control apparatus for a vehicle that includes an internal combustion engine and an electric motor, and that is capable of traveling by motive power from at least one of the internal combustion engine and the electric motor includes: a control portion that causes the vehicle to travel in a travel mode of a plurality of travel modes that differ in an engine start condition for the internal combustion engine; and a determination portion that determines whether exhaust from the internal combustion engine has deteriorated, wherein the determination portion changes the deterioration determination condition for determining that the exhaust has deteriorated, according to the travel mode.

Abstract: The hybrid vehicle executes a diagnosis of a component related to exhaust qualities during a fuel-cut operation of the internal combustion engine and generates a fuel-cut request to execute the diagnosis. When the internal combustion engine is operated in an idle state, the hybrid vehicle feedback-controls a throttle valve opening (control parameter) such that an engine rotation speed is maintained at a target idle rotation speed, and learns a value corresponding to the control parameter as a learned value for controlling the idle operation in a state where the vehicle speed is not more than a learning permission vehicle speed and the internal combustion engine is operated in the idle state. The hybrid vehicle continues generation of the fuel-cut request until the learning of the idle operation control learned value is completed.

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: An ECU performs a failure diagnosis for a thermostat valve after starting of an engine based on an output of an engine-side coolant water temperature sensor and an output of a radiator-side coolant water temperature sensor. When an electric pump operates in accordance with a heating request or the like of an air-conditioning device during stopping of the engine, the thermostat valve attains a closed state. When the electric pump operates during stopping of the engine before the current starting of the engine, starting of the failure diagnosis performed after starting of the engine is delayed as compared to the case where the electric pump does not operate during stopping of the engine. Consequently, erroneous determination can be suppressed in the failure diagnosis for the thermostat valve.

Abstract: A learning unit learns a difference between a detected value ECT and a detected value RCT when it is determined that the detected value ECT and detected value RCT are stable while an engine is at a stop. A diagnostic unit performs a fault diagnosis for the engine based on the difference between the detected value ECT and detected value RCT having been corrected through use of a learned value learned by the learning unit. Accordingly, a fault diagnostic system for an internal combustion engine and a fault diagnostic method for an internal combustion engine can be achieved in which accuracy in fault diagnosis for the internal combustion engine can be improved and an erroneous diagnosis can be restrained.

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: The hybrid vehicle executes a diagnosis of a component related to exhaust qualities during a fuel-cut operation of the internal combustion engine and generates a fuel-cut request to execute the diagnosis. When the internal combustion engine is operated in an idle state, the hybrid vehicle feedback-controls a throttle valve opening (control parameter) such that an engine rotation speed is maintained at a target idle rotation speed, and learns a value corresponding to the control parameter as a learned value for controlling the idle operation in a state where the vehicle speed is not more than a learning permission vehicle speed and the internal combustion engine is operated in the idle state. The hybrid vehicle continues generation of the fuel-cut request until the learning of the idle operation control learned value is completed.

Abstract: In a malfunction determination apparatus and a malfunction determination method for a cooling apparatus that cools an internal combustion engine by circulating a cooling medium that flows in a first passage that extends through an inside of the engine, using an electric pump, a first temperature of the cooling medium is detected at an inlet of the first passage, through which the cooling medium flows into the inside of the engine; a second temperature of the cooling medium is detected at an outlet of the first passage, through which the cooling medium flows out from the inside of the engine; and it is determined that the switching valve is able to normally select the second passage, if both of the first temperature and the second temperature reach a first threshold value when a temperature of the cooling medium increases due to start of the engine.

Abstract: In an engine having a variable valve timing mechanism to which an intermittent operation control is applied, appropriate execution of a foreign object removal process for the variable valve timing mechanism is enabled. An engine control device (16) which can execute intermittent operation control for an engine (12) having a variable valve timing mechanism (80) comprises a judging part which judges an abnormality in the variable valve timing mechanism (80) (step S10), a foreign object removal process executing part which causes a foreign object removal process to be executed for the variable valve timing mechanism (80) when the judging part judges that there is an abnormality in the variable valve timing mechanism (80) during an engine operation (step S12), and an intermittent operation control prohibiting part which prohibits the intermittent operation control of the engine (12) during execution of the foreign object removal process of the variable valve timing mechanism (80) (step S16).

Abstract: Upon satisfaction of the condition for making the malfunction diagnosis at least one of the EGR system, the air-fuel ratio sensor and the oxygen sensor during the fuel cut of the engine, a fuel cut of the engine and performing the mortaring of the engine by means of the motor MG1 are continued until the completion of the malfunction diagnoses of all objects, of which the each condition for making the malfunction diagnosis is satisfied among the EGR system, the air-fuel ratio sensor and the oxygen sensor. This arrangement ensures the occasions for making the malfunction diagnoses of the EGR system, the air-fuel ratio sensor and the oxygen sensor.

Abstract: A vehicle control apparatus for a vehicle that includes an internal combustion engine and an electric motor, and that is capable of traveling by motive power from at least one of the internal combustion engine and the electric motor includes: a control portion that causes the vehicle to travel in a travel mode of a plurality of travel modes that differ in an engine start condition for the internal combustion engine; and a determination portion that determines whether exhaust from the internal combustion engine has deteriorated, wherein the determination portion changes the deterioration determination condition for determining that the exhaust has deteriorated, according to the travel mode.