CLUTCH CONTROL DEVICE FOR 4-WHEEL DRIVE VEHICLE

摘要

A clutch control device is provided for a four-wheel drive vehicle for transmitting drive force to the rear wheels. The clutch control device includes a dog clutch and a friction clutch, and a controller that controls the dog clutch and the friction clutch. The controller starts the engagement of the dog clutch, after placing the dog clutch in a rotationally synchronized state by engaging the friction clutch and increasing an output rotation thereof, when there is a request to engage the dog clutch. In this clutch control device, the controller sets the engagement start timing of the friction clutch when a transition is made to the connected, four-wheel drive mode to an earlier timing compared to when a transition is made to the standby two-wheel drive mode, when there is a request to engage the dog clutch while in a state in which the disconnected, two-wheel drive mode is selected.

主权项

1. A clutch control device for a four-wheel drive vehicle having a pair of main drive wheels and a pair of auxiliary drive wheels which are selectively connected to the drive source, the clutch control device comprising:
a dog clutch operatively disposed in a transmission path between the main drive wheels and the auxiliary drive wheels to separate a system for transmitting drive force to the auxiliary drive wheels from a system for transmitting drive force to the main drive wheels by releasing the dog clutch; a friction clutch operatively disposed in a transmission path between the main drive wheels and the auxiliary drive wheels to allocate a portion of the drive force from the drive source to the auxiliary drive wheels in accordance with a clutch engagement capacity of the friction clutch; and a clutch controller operatively coupled to the dog clutch and the friction clutch to selectively carry out a control of starting an engagement of the dog clutch, which is in a disengaged state, after putting the dog clutch into a rotationally synchronized state by engaging the friction clutch, in response to a request to engage the dog clutch, the clutch controller being programmed to selectively establish a disconnected, two-wheel drive mode in which the dog clutch and the friction clutch are disengaged, a standby two-wheel drive mode in which the dog clutch is engaged and the friction clutch is disengaged, and a connected, four-wheel drive mode in which the dog clutch and the friction clutch are engaged, and the clutch controller being programmed to set an engagement start timing of the friction clutch when a transition is made to the connected, four-wheel drive mode to an earlier timing as compared to when a transition is made to the standby two-wheel drive mode, in response to a request to engage the dog clutch while in a state in which the disconnected, two-wheel drive mode is selected.