Vehicular power transmission control apparatus

A vehicular power transmission control apparatus comprising:

• a multiple gear ratio transmission including an input shaft to which power is inputted from an output shaft of an internal combustion engine, and an output shaft from which the power is outputted to a drive wheel of a vehicle, and includes a plurality of gear positions, each of which has a different speed reducing ratio that is a ratio of a revolution speed of the input shaft to a revolution speed of the output shaft of the multiple gear ratio transmission;
• a clutch that is mounted directly between the output shaft of the internal combustion engine and the input shaft of the multiple gear ratio transmission, and that can adjust a clutch torque, which is a maximum torque that the clutch can transmit;
• and
• a control unit that controls the clutch torque of the clutch and a gear position of the multiple gear ratio transmission based upon a driving condition of the vehicle, wherein
• the control unit controls the clutch torque of the clutch such that a revolution speed of the input shaft of the multiple gear ratio transmission becomes smaller than a revolution speed of the output shaft of the internal combustion engine by a predetermined positive value in a semi-engagement state with a slip, when the vehicle drives with the gear position of the multiple gear ratio transmission set to a low speed range comprises at least a gear position having a greatest speed reducing ratio, while the control unit controls the clutch torque of the clutch such that the revolution speed of the input shaft of the multiple gear ratio transmission is equal to the revolution speed of the output shaft of the internal combustion engine in a total engagement state without the slip, when the vehicle drives with the gear position of the multiple gear ratio transmission set to a gear position other than the low speed range and which has a speed reducing ratio smaller than that of the gear positions in the low speed range,
• wherein when the transmission is set to the lowest speed range and the drive torque of the engine sharply decreases, to suppress torsional vibration the clutch torque is controlled in a semi-engagement state in which when a difference in revolution speed, which is a difference obtained by subtracting the revolution speed Ni of the input shaft of the transmission from the revolution speed Ne of the output shaft of the internal combustion engine, is greater than a predetermined value A, the clutch torque is increased, and when the difference in revolution speed is less than the predetermined value A, the clutch torque is decreased.