Device for controlling 4wd vehicle central differential restriction device according to vehicle road speed and engine load, and method of operation thereof

摘要

In a four wheel drive vehicle, a central differential device receives rotational power from an engine and provides it to the combination of the front wheels of the vehicle and also to the combination of the rear wheels of the vehicle. This central differential device includes a device for selectively restricting its operation. A control device is provided for this central differential device operation restriction device, and includes: (a) a means for detecting a condition representative of the road speed of the vehicle and of the load on the engine; and (b) a means for controlling the device for selectively restricting the operation of the central differential device, so that the operation of the central differential device is less restricted than otherwise, when the vehicle speed is relatively high and also the engine output is not relatively high. Various specializations of this control device, and also the method of operation thereof, are also disclosed.