Fluid transmission device

摘要

A fluid transmission device includes a fluid transmission section capable of transmitting power transmitted to an input member to an output member via a working fluid, a lock-up clutch section capable of transmitting power transmitted to the input member to the output member via a friction engagement section, and a control unit configured to execute a torque ratio variable control that makes a torque ratio which is a ratio between torque output from the output member and torque input to the input member variable by adjusting a friction engagement state of the friction engagement section, when the fluid transmission section is in an operation state that the fluid transmission section amplifies torque input to the input member and outputs torque from the output member.

主权项

1. A fluid transmission device comprising:
a torque converter configured to include an input member connected to an internal combustion engine which is supercharged by a supercharger, a fluid transmission section capable of transmitting power transmitted to the input member to an output member via a working fluid, and a lock-up clutch section capable of transmitting power transmitted to the input member to the output member via a friction engagement section; and a control unit configured to execute a torque ratio variable control that makes a torque ratio in the overall torque converter which is a ratio between torque output from the output member and torque input to the input member variable by adjusting a friction engagement state of the friction engagement section, at the timing a vehicle on which the torque converter is mounted starts; and a target torque ratio setting unit configured to calculate a target value of the torque ratio in the overall torque converter in a range which is equal to or less than a torque ratio of the fluid transmission section as well as equal to or more than 1 in accordance with a deviation between target engine torque that is assumed to be generated by the internal combustion engine when a supercharging is executed without a supercharging delay and actual engine torque actually generated by the internal combustion engine, wherein the target torque ratio setting unit corrects the target value so that the target value becomes equal to or less than an allowable torque in a power transmission system to which the torque output from the output member is transmitted, the control unit adjusts the friction engagement state of the friction engagement section based on the target value at a timing the torque ratio of the fluid transmission section is more than 1.