Abstract: A vehicle drive system includes an internal combustion engine, a clutch, an engine rotation speed detector, an output shaft rotation speed detector, and a processor. The internal combustion engine includes cylinders and a crankshaft. The clutch is connected to the crankshaft via a torsion element and includes an output shaft. The engine rotation speed detector detects a crankshaft rotation speed. The output shaft rotation speed detector detects an output shaft rotation speed. The processor is configured to calculate a torque generated in each of the cylinders based on the crankshaft rotation speed. The processor is configured to decrease transmission torque of the clutch so that a difference between the crankshaft rotation speed and the output shaft rotation speed to be a target value when misfiring occurs. The processor is configured to identify a misfiring cylinder among the cylinders based on the torque calculated while the transmission torque is decreased.

Abstract: A vehicle drive system includes an internal combustion engine, a clutch, an engine rotation speed detector, an output shaft rotation speed detector, and a processor. The internal combustion engine includes cylinders and a crankshaft. The clutch is connected to the crankshaft via a torsion element and includes an output shaft. The engine rotation speed detector detects a crankshaft rotation speed. The output shaft rotation speed detector detects an output shaft rotation speed. The processor is configured to calculate a torque generated in each of the cylinders based on the crankshaft rotation speed. The processor is configured to decrease transmission torque of the clutch so that a difference between the crankshaft rotation speed and the output shaft rotation speed to be a target value when misfiring occurs. The processor is configured to identify a misfiring cylinder among the cylinders based on the torque calculated while the transmission torque is decreased.

Abstract: The present invention provides a diagnostic apparatus for an evaporative emission control system which can accurately execute leak diagnosis under a stable condition. An ECU clocks a time td2 until the internal pressure value Pte of the evaporative emission control system sealed at the negative pressure reaches the target internal pressure value Pd, sets the pressure change measuring time te2 based on the clocking time td2, and measures the pressure change amount P1 which varies after the internal pressure value Pte of the evaporative emission control system reaches the target internal pressure value Pd for a pressure change measuring time te2. Then, the ECU sets the determination value Pth0 based at least on the spatial capacity of the evaporative emission control system, and determines whether the evaporative emission control system is normal or abnormal based on the pressure change amount P1.

Abstract: An inside of an evaporated fuel processing system including a fuel tank is closed after changing an internal pressure of the evaporated fuel processing system to a target pressure value. After the closing, a diagnostic section variably sets a start timing for calculating a pressure change within the evaporated fuel processing system based on a timing when the internal pressure of the evaporated fuel processing system changes from the target pressure value to a peak pressure value. Then, a change amount between the respective internal pressure values detected by a detector at the set start timing and at a termination timing, which comes after the start timing, is calculated. The diagnostic section diagnose a leak within the evaporated fuel processing system based on the calculated change amount. Thus, the variably set start timing allows the diagnosis time to be shortened.

Abstract: In a diagnostic apparatus for an evaporative emission control system having a fuel tank is hermetically sealed under negative pressure on the basis of target inner pressure, and leak of the evaporative emission control system is judged when a diagnosis value based on a pressure variation amount after the hermetical sealing under at least negative pressure is larger than a judgment value, ECU estimates an evaporated fuel generated amount on the basis of a tank inner pressure value at the start time of a diagnosis. When the evaporated fuel generated amount thus estimated is large, target inner pressure Pteb is set to a high value, and when the evaporated fuel generated amount thus estimated is small, the target inner pressure Pteb is set to a low value.

Abstract: A valve control section of a diagnostic device for an evaporated fuel processing system closes an evaporated fuel processing system at closing timing at which a value of the internal pressure detected by an internal pressure detection section reaches a preset target pressure value after a negative pressure is introduced from an inlet system to the evaporated fuel processing system. A diagnostic section of the device compares the internal pressure value at diagnostic timing which is set so as to come after the closing timing with a preset criterion threshold value so as to execute a leak diagnosis of the evaporated fuel processing system. A calculation section of the device variably sets the diagnostic timing based on the intake negative pressure value detected by the intake pressure detection section. Thus, a time period required for an early diagnosis of the leak can be optimized.

Abstract: In a diagnostic apparatus for an evaporative emission control system having a fuel tank is hermetically sealed under negative pressure on the basis of target inner pressure, and leak of the evaporative emission control system is judged when a diagnosis value based on a pressure variation amount after the hermetical sealing under at least negative pressure is larger than a judgment value, ECU estimates an evaporated fuel generated amount on the basis of a tank inner pressure value at the start time of a diagnosis. When the evaporated fuel generated amount thus estimated is large, target inner pressure Pteb is set to a high value, and when the evaporated fuel generated amount thus estimated is small, the target inner pressure Pteb is set to a low value.

Abstract: A state of an energization of a normal open type drain valve interposed between a fresh air introducing port of a canister and a drain filter is checked. And if the valve is not the energized state (open state), the tank internal pressure is checked. If the tank internal pressure is lower than a predetermined value and the state is maintained for a predetermined time, it is determined that the drain valve is close-stuck. If the drain valve is close-stuck, the pressure in the canister becomes negative, and the negative pressure is introduced in a fuel tank via a passage to an atmosphere and a pressure control valve. Closed sticking of the drain valve can be detected by checking the tank internal pressure.

Abstract: The present invention provides a diagnostic apparatus for an evaporative emission control system which can accurately execute leak diagnosis under a stable condition. An ECU clocks a time td2 until the internal pressure value Pte of the evaporative emission control system sealed at the negative pressure reaches the target internal pressure value Pd, sets the pressure change measuring time te2 based on the clocking time td2, and measures the pressure change amount P1 which varies after the internal pressure value Pte of the evaporative emission control system reaches the target internal pressure value Pd for a pressure change measuring time te2. Then, the ECU sets the determination value Pth0 based at least on the spatial capacity of the evaporative emission control system, and determines whether the evaporative emission control system is normal or abnormal based on the pressure change amount P1.

Abstract: A valve control section of a diagnostic device for an evaporated fuel processing system closes an evaporated fuel processing system at closing timing at which a value of the internal pressure detected by an internal pressure detection section reaches a preset target pressure value after a negative pressure is introduced from an inlet system to the evaporated fuel processing system. A diagnostic section of the device compares the internal pressure value at diagnostic timing which is set so as to come after the closing timing with a preset criterion threshold value so as to execute a leak diagnosis of the evaporated fuel processing system. A calculation section of the device variably sets the diagnostic timing based on the intake negative pressure value detected by the intake pressure detection section. Thus, a time period required for an early diagnosis of the leak can be optimized.

Abstract: An inside of an evaporated fuel processing system including a fuel tank is closed after changing an internal pressure of the evaporated fuel processing system to a target pressure value. After the closing, a diagnostic section variably sets a start timing for calculating a pressure change within the evaporated fuel processing system based on a timing when the internal pressure of the evaporated fuel processing system changes from the target pressure value to a peak pressure value. Then, a change amount between the respective internal pressure values detected by a detector at the set start timing and at a termination timing, which comes after the start timing, is calculated. The diagnostic section diagnose a leak within the evaporated fuel processing system based on the calculated change amount. Thus, the variably set start timing allows the diagnosis time to be shortened.

Abstract: A state of an energization of a normal open type drain valve interposed between a fresh air introducing port of a canister and a drain filter is checked. And if the valve is not the energized state (open state), the tank internal pressure is checked. If the tank internal pressure is lower than a predetermined value and the state is maintained for a predetermined time, it is determined that the drain valve is close-stuck. If the drain valve is close-stuck, the pressure in the canister becomes negative, and the negative pressure is introduced in a fuel tank via a passage to an atmosphere and a pressure control valve. Closed sticking of the drain valve can be detected by checking the tank internal pressure.