Control device and control method for vehicle, and non-transitory computer readable medium

A control method for a vehicle, the control method being for controlling engagement/disengagement of a lock-up clutch of a torque converter interposed between an engine and a stepped transmission mechanism, and selecting any one of a first driving mode and a second driving mode, the control method comprising:

• disengaging, in a case where the first driving mode is selected, the lock-up clutch when a vehicle speed decreases and reaches a first vehicle speed while the vehicle is travelling in a state where the lock-up clutch is engaged;
• disengaging, in a case where the second driving mode is selected, the lock-up clutch when the vehicle speed decreases and reaches a second vehicle speed in a brake operation OFF state while the vehicle is travelling in the state where the lock-up clutch is engaged;
• disengaging, in the case where the second driving mode is selected, the lock-up clutch when the vehicle speed decreases and reaches a third vehicle speed in a brake operation ON state while the vehicle is travelling in the state where the lock-up clutch is engaged;
• and
• setting the third vehicle speed to a vehicle speed lower than the first vehicle speed, and setting the second vehicle speed to a vehicle speed higher than the first vehicle speed.

A non-transitory computer-readable medium storing a program executable by a computer of a vehicle having a lock-up clutch of a torque converter interposed between an engine and a stepped transmission mechanism and a driving mode selector configured to select any one of a first driving mode and a second driving mode, the program causing the computer to execute:

• in a case where the first driving mode is selected, disengaging the lock-up clutch when a vehicle speed decreases and reaches a first vehicle speed while the vehicle is travelling in a state where the lock-up clutch is engaged,
• in a case where the second driving mode is selected, disengaging the lock-up clutch when the vehicle speed decreases and reaches a second vehicle speed in a brake operation OFF state while the vehicle is travelling in the state where the lock-up clutch is engaged,
• in the case where the second driving mode is selected, disengaging the lock-up clutch when the vehicle speed decreases and reaches a third vehicle speed in a brake operation ON state while the vehicle is travelling in the state where the lock-up clutch is engaged, and
• setting the third vehicle speed to a vehicle speed lower than the first vehicle speed, and setting the second vehicle speed to a vehicle speed higher than the first vehicle speed.