All-wheel drive system

An all-wheel drive system comprising:

• a center differential configured to distribute torque input thereto between front wheels and rear wheels of a vehicle;
• a limited-slip differential clutch configured to limit a differential operation of the center differential in accordance with an engaging pressure and change a front-rear torque distribution ratio between the front wheels and the rear wheels;
• a front-wheel torque transmission system configured to transmit torque between the center differential and the front wheels;
• a rear-wheel torque transmission system configured to transmit torque between the center differential and the rear wheels;
• and
• a controller configured to adjust the engaging pressure of the limited-slip differential clutch based on a driving state of the vehicle,
• wherein a reduction ratio of the front-wheel torque transmission system and a reduction ratio of the rear-wheel torque transmission system are set to be different from each other, and
• wherein the center differential is configured such that the front-rear torque distribution ratio is initially unequal and is changeable,
• wherein the controller adjusts the engaging pressure of the limited-slip differential clutch in a case where the driving state of the vehicle is accelerated cornering or accelerated climbing, and disengages the limited-slip differential clutch in a case where the driving state of the vehicle is other than the accelerated cornering or the accelerated climbing,
• wherein the controller disengages the limited-slip differential clutch in a case where an oil temperature of the limited-slip differential clutch is higher than or equal to a predetermined temperature.

A program for an all-wheel drive system stored in a non-transitory computer readable medium, the all-wheel drive system, comprising

• a center differential configured to distribute torque input thereto between front wheels and rear wheels of a vehicle,
• a limited-slip differential clutch configured to limit a differential operation of the center differential in accordance with an engaging pressure and change a front-rear torque distribution ratio between the front wheels and the rear wheels,
• a front-wheel torque transmission system configured to transmit torque between the center differential and the front wheels, and
• a rear-wheel torque transmission system configured to transmit torque between the center differential and the rear wheels,
• the program executable by processor and configured to:
• adjust the engaging pressure of the limited-slip differential clutch based on a driving state of the vehicle;
• and
• setting a reduction ratio of the front-wheel torque transmission system and a reduction ratio of the rear-wheel torque transmission system to be different from each other, and
• wherein the center differential is configured such that the front-rear torque distribution ratio is initially unequal and is changeable.