Patent ID: 8585544
Filing Date: 2013-11-19
Classification: B60W,F16H,Y10T

Abstract:
1. A drive force control system, which is applied to a vehicle having an internal combustion engine functioning as a prime mover and a continuously variable transmission arranged in an output side of the internal combustion engine to which power of the internal combustion engine is transmitted, and which is configured to carry out a control for changing a speed change ratio of the continuously variable transmission stepwise, comprising: a torque reversing mechanism having a forward clutch and a reverse brake, which is configured to transmit the power outputted from the internal combustion engine to the continuously variable transmission without changing a direction of torque by engaging the forward clutch and disengaging the reverse brake, and to transmit the power outputted from the internal combustion engine to the continuously variable transmission while reversing the direction of torque by engaging the reverse brake and disengaging the forward clutch; a shifting demand judging means, which is adapted to judge whether or not a torque capacity of the forward clutch is relatively high, and a condition for changing the speed change ratio of the continuously variable transmission stepwise is satisfied; a first shifting means, which is adapted to reduce the torque capacity of the forward clutch before changing the speed change ratio of the continuously variable transmission, to synchronize a rotational speed of the internal combustion engine with an input speed of the continuously variable transmission to be attained after changing the speed change ratio thereof while changing the speed change ratio of the continuously variable transmission, and to increase the torque capacity of the forward clutch after changing the speed change ratio of the continuously variable transmission, in case the shifting demand judging means judges that the torque capacity of the forward clutch is relatively high, and a condition for changing the speed change ratio of the continuously variable transmission stepwise is satisfied while the vehicle is running; and a condition judging means, which is adapted to judge whether or not the torque capacity of the forward clutch is allowed to be reduced, wherein: the first shifting means includes a means adapted to reduce the torque capacity of the forward clutch, to synchronize the rotational speed of the internal combustion engine with a rotational speed to be attained after changing the speed change ratio of the continuously variable transmission, and to increase the torque capacity of the forward clutch, in case the shifting demand judging means judges that the condition for changing the speed change ratio of the continuously variable transmission stepwise is satisfied, and the condition judging means judges that the torque capacity of the forward clutch is allowed to be reduced, and the condition judging means includes a means adapted to judge a fact that the torque capacity of the forward clutch is allowed to be reduced on the basis of a fact that a driver of the vehicle is not carrying out an accelerating operation.