A vehicle control device applicable to a vehicle including an engine includes an electric motor coupled to the engine, a hydraulic clutch, a solenoid control valve, a first travel control unit, a second travel control unit, and a fail-safe control unit. The hydraulic clutch is engaged when hydraulic oil is supplied and disengaged when the hydraulic oil is discharged. The solenoid control valve includes a solenoid. The solenoid control valve supplies the hydraulic oil to the hydraulic clutch when the solenoid is in a non-energized state, and discharges the hydraulic oil when the solenoid is in the energized state. The first travel control unit executes an engine traveling mode, and the second travel control unit executes an inertial traveling mode. The fail-safe control unit drives the electric motor when the solenoid is switched from the energized state to the non-energized state while the inertial traveling mode is executed.

Disclosed is a method for controlling engagement of an engine clutch in a hybrid electric vehicle in which an engagement control method of the engine clutch is accurately determined so as to minimize a determination error and a sense of discontinuity caused by conversion of the engagement control method resulting therefrom.

A controller executes a method to manage an engine connect/disconnect decision in a powertrain having an engine, transmission, electric machine, and a battery pack and power inverter module (“TPIM”). In response to vehicle ground speed being less than a calibrated maximum electric vehicle accelerator pedal signal (“EV.sub.APS”) level, the controller calculates a delta APS (“ΔAPS”) value by subtracting a scaled APS value from the actual APS level. The scaled APS value is a scaled variant of a maximum EV.sub.APS value selected from a maximum EVS.sub.APS table, the latter populated based on inverter temperature, state of charge of the battery pack, and ground speed. When the ΔAPS value exceeds a threshold, the controller connects the engine to the transmission via an engine disconnect clutch. The engine is disconnected based on acceleration of the vehicle and the above-noted factors.

Disclosed is a method for controlling engagement of an engine clutch in a hybrid electric vehicle in which an engagement control method of the engine clutch is accurately determined so as to minimize a determination error and a sense of discontinuity caused by conversion of the engagement control method resulting therefrom.

A vehicle control device applicable to a vehicle including an engine includes an electric motor coupled to the engine, a hydraulic clutch, a solenoid control valve, a first travel control unit, a second travel control unit, and a fail-safe control unit. The hydraulic clutch is engaged when hydraulic oil is supplied and disengaged when the hydraulic oil is discharged. The solenoid control valve includes a solenoid. The solenoid control valve supplies the hydraulic oil to the hydraulic clutch when the solenoid is in a non-energized state, and discharges the hydraulic oil when the solenoid is in the energized state. The first travel control unit executes an engine traveling mode, and the second travel control unit executes an inertial traveling mode. The fail-safe control unit drives the electric motor when the solenoid is switched from the energized state to the non-energized state while the inertial traveling mode is executed.

A controller executes a method to manage an engine connect/disconnect decision in a powertrain having an engine, transmission, electric machine, and a battery pack and power inverter module (TPIM). In response to vehicle ground speed being less than a calibrated maximum electric vehicle accelerator pedal signal (EV.sub.APS) level, the controller calculates a delta APS (PS) value by subtracting a scaled APS value from the actual APS level. The scaled APS value is a scaled variant of a maximum EV.sub.APS value selected from a maximum EVS.sub.APS table, the latter populated based on inverter temperature, state of charge of the battery pack, and ground speed. When the APS value exceeds a threshold, the controller connects the engine to the transmission via an engine disconnect clutch. The engine is disconnected based on acceleration of the vehicle and the above-noted factors.

A basic clutch capacity calculating unit calculates a clutch capacity of the DCT applying an engine speed, a degree of throttle opening, and a front wheel vehicle speed to a map. The basic clutch capacity calculating unit further calculates the DCT basic clutch capacity by amending the basic clutch capacity based on an oil temperature and a water temperature. An NE converted value calculating unit calculates an NE converted value obtained by converting a vehicle speed into an engine speed with the front wheel vehicle speed and a DCT speed change stage as input parameters. A hunting detecting unit detects hunting by comparing the engine speed with the NE converted value when a throttle operation is detected. A DCT clutch capacity correcting unit makes decreasing correction of a DCT clutch capacity when hunting is detected for suppressing the hunting.

An object of the invention is to provide a hybrid vehicle control device capable of shortening the time from an engine start request to the engine start. The hybrid vehicle control device is provided with an integrated controller configured to execute processing for starting an engine by bringing a first clutch into engagement, while slipping a second clutch, and by increasing a torque of a motor generator, when it has been determined that an engine start request is present, and a first clutch engagement control section, which is included in the integrated controller and configured to command a start of engagement of the first clutch once the difference between the torque of the motor generator and a second clutch transmitted torque capacity command value becomes greater than or equal to a preset slip prediction determination threshold value after having been determined that the engine start request is present.

A basic clutch capacity calculating unit calculates a clutch capacity of the DCT applying an engine speed, a degree of throttle opening, and a front wheel vehicle speed to a map. The basic clutch capacity calculating unit further calculates the DCT basic clutch capacity by amending the basic clutch capacity based on an oil temperature and a water temperature. An NE converted value calculating unit calculates an NE converted value obtained by converting a vehicle speed into an engine speed with the front wheel vehicle speed and a DCT speed change stage as input parameters. A hunting detecting unit detects hunting by comparing the engine speed with the NE converted value when a throttle operation is detected. A DCT clutch capacity correcting unit makes decreasing correction of a DCT clutch capacity when hunting is detected for suppressing the hunting.

In a control system and a control method, an electronic control unit is configured to crank an engine by setting a clutch to a half engaged state in a state where operation of the engine is stopped during traveling. The half engaged state is a state where the clutch is engaged with a slip. The electronic control unit is configured to, after a rotation speed of the engine has reached an ignition permission rotation speed or higher, increase a transmitted torque capacity of the clutch to a transmitted torque capacity that satisfies the following conditions i) and ii): i) the transmitted torque capacity is larger than a transmitted torque capacity before the rotation speed of the engine has reached the ignition permission rotation speed; and ii) the transmitted torque capacity allows the clutch to be kept in the half engaged state.