Driving control device and driving control method in hybrid electric vehicle

A driving control method of a hybrid electric vehicle, the vehicle comprising an internal combustion engine, an electric motor/generator, and a clutch connecting the internal combustion engine and the electric motor/generator, the driving control method comprising:

• detecting whether or not the clutch is engaged;
• detecting whether or not the internal combustion engine is in operation;
• detecting whether or not a request for stopping operation of the internal combustion engine has been input;
• determining, when the request for stopping operation of the combustion engine has been input in a state where the internal combustion engine is in operation and the clutch is engaged in a vehicle stationary state, whether or not the clutch can be disengaged within a predetermined time period;
• if the clutch can be disengaged within the predetermined time period, disengaging the clutch and control an operation stop of the internal combustion engine by cutting off a fuel to cause a rotation speed of the internal combustion engine to decrease below a predetermined resonance frequency band while the clutch is disengaged, and
• if the clutch cannot be disengaged within the predetermined time period, decreasing an output torque of the internal combustion engine to a predetermined torque in a state where the clutch is engaged and thereafter stopping the operation of the internal combustion engine.

A driving control device of a hybrid electric vehicle, the vehicle comprising an internal combustion engine, an electric motor/generator, and a clutch that connects the internal combustion engine and the electric motor/generator, the driving control device comprising:

• means for detecting whether or not the clutch is engaged;
• means for detecting whether or not the internal combustion engine is in operation;
• means for detecting whether or not a request for stopping operation of the internal combustion engine has been input;
• means for determining, when the request for stopping operation of the combustion engine has been input in a state where the internal combustion engine is in operation and the clutch is engaged in a vehicle stationary state, whether or not the clutch can be disengaged within a predetermined time period;
• means for disengaging the clutch and controlling an operation stop of the internal combustion engine by cutting off a fuel to cause a rotation speed of the internal combustion engine to decrease below a predetermined resonance frequency band while the clutch is disengaged, if the clutch can be disengaged within the predetermined time period, and
• means for decreasing an output torque of the internal combustion engine to a predetermined torque in a state where the clutch is engaged and thereafter stopping the operation of the internal combustion engine, if the clutch cannot be disengaged within the predetermined time period.