Many people think that four-wheel-drive cars can run on any surface and go wherever they want. In fact, this is an exaggeration of the ability of four-wheel drive vehicles. Friends who have driven four-wheel drive off-road vehicles may know that on bad roads, the differential of the car allows only one wheel of each axle to be driven, and it is constantly driving. skidding. So four-wheel drive is not a universal vehicle, you must know what the four-wheel drive system is all about.
Timely four-wheel drive
Only when appropriate will it switch to four-wheel drive, while otherwise it will remain a two-wheel-drive drive system. This four-wheel drive system will automatically switch to two-wheel drive or four-wheel drive mode according to the driving conditions of the vehicle, without human operation.
Advantages: The structure of the timely four-wheel drive should be simple, which is beneficial to reduce the cost and the weight of the whole vehicle. With the four-wheel drive system, comfort and economy are also taken into account.
Disadvantages: Due to its own structural problems, more than 50% of the power cannot be transmitted to the rear axle. The front and rear axles of the timely four-wheel drive system basically use open differentials. When two wheels on one side slip, they cannot get out of trouble of. Therefore, this four-wheel drive system cannot cope with strong off-road sections.
full-time four-wheel drive
Full-time four-wheel drive is any time, and the vehicle is a four-wheel drive system with four wheels independently propelled. The full-time four-wheel drive distributes the driving force to the four tires through a flexible central differential, and then through independent differentials on the front and rear axles. Different from the purely mechanical differential lock, the differential of the full-time four-wheel drive can be a bonded coupling type or a multi-clutch type, but the same is that it can allow a gap between the front and rear wheels and the left and right wheels. Poor speed.
Advantages: Greater traction especially in slippery and winter conditions, stability when driving in mud and trampled snow; balanced axle load distribution; reduced torque steer effect; even tires wear and tear.
Disadvantages: complex structure, troublesome maintenance, high vehicle cost; compared with front-wheel drive vehicles, the trunk is relatively small, and one side of the wheel cannot be dragged separately when towing the vehicle.
part-time four-wheel drive
Part- time Time-sharing four-wheel drive usually only uses four-wheel drive of the front wheels or rear wheels to drive, and can be switched to four-wheel drive on snow or gravel roads, which is also called four-wheel drive selection. This is also the most common drive mode for off-road vehicles.
Advantages: simple structure, high stability, solid and durable, economical, and strong off-road capability.
Disadvantages: Four-wheel drive switching is cumbersome to operate and must be operated manually. At the same time, parking operation is required; because part-time four-wheel drive does not have a central differential, the four-wheel drive system cannot be used on paved roads, especially on curves. turn.
Source of pictures and texts: Original article by SUV Master, author Liu Xingyu.
