What is four-wheel drive 4WD?


1-wheel drive 4WD


4WD (four-wheel drive, which in English is 4 wheel drive) via a transmission means to help a low rate car overcome the muddy and slippery snow, just as in the general driving off-road (off-road), rocky terrain and rolling hills. The cars must be a shift in the low ratio gear or low speed, when stopped, and the shift is performed by a shift lever or button.

all-wheel drive (4WD system) is the driving force of the engine from the transmission 2wd two transmission system becomes four. 4wd system and are included in active safety systems, mainly 4wd system is more excellent than 2wd engine driving force application efficiency, achieve better tire traction and steering effective force. On security for, 4wd tire traction and steering system for better application of force, resulting in good driving stability and tracking of. In addition to more 2wd 4wd system does not have off-road.

4WD is classified as follows

four-wheel drive (Part-time 4WD):

this is a four-wheel drive system for a driver to manually select between two drive and four-wheel drive, according to road conditions, be varied by the driver by turning on or off the splitter two-wheel drive or four-wheel drive model, the most common of which is the general four-wheel drive sport utility vehicle or SUV driving mode. The most significant advantage is that the driving mode can be selected according to the actual situation, more economical. 2.8 breeze displacement of the four-wheel drive SUV is a typical example, which has three drive mode selection: 2H use with high-speed two-wheel drive on the road profile; when encountered snow road, 4H select high-speed driving, enhanced the adhesion and handling of the vehicle: the faceWhen the challenge poor road conditions, may be employed 4L breeze and low four-wheel drive, so that force acting on all four wheels, thereby reducing the requirements for each tire adhesion, minimizes the possibility of wheel slip during turning. Engine braking ability can be enhanced, greatly improves the controllability of the throttle in the case of the sudden closure of the vehicle is traveling over rough or smooth surfaces. In 2003, on the 2004 national cross-country venue, Landwind 2.8 diesel four-wheel displacement, regardless encounter bumpy stone road, or very steep angle of the V-shaped grooves, deep muddy after heavy rains abnormal, even half a man deep the large pond, can easily deal with, Yiqijuechen, won countless races and the finals of the national championships, four-wheel drive can be said to describe the most heroic performance.

AWD (Full-time 4WD):

The drive system is not required to select the driver operation, the front and rear wheels will always maintain four wheel drive mode, the engine output torque during traveling 50:50 on the front and rear wheels to set the front and rear wheels to maintain the same amount of torque. Full-time drive system has a good driving handling and tracking of travel, with full-time four-wheel drive system, you can successfully driving on paved roads covered. But its disadvantages are also obvious, and that is a comparison of oil, the economy is not good enough. Moreover, there is no device to control the vehicle tire speed difference, once a tire off the ground, tend to make you stuck in there, we can not move forward.

timely drive (Real-time 4WD):

using timely drive system of the vehicle may be controlled by a computer select the drive mode is suitable for the current situation. In normal road, rear-wheel drive vehicles generally the way. Once the wheel slip or poor road surface conditions encountered, the computer automatically detects the engine output torque is immediately assigned to the two front wheels, the natural state so as to switch to four-wheel drive in addition to the driver’s judgment and manual operation, the application easier. However, compared with the computer brain, slow reaction after all, and in so doing, also they lack the sense of conquest that everything is under control and driving pleasure.

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