Four wheel drive strategy, four wheel drive characteristics

Four-wheel drive cars will have a stronger grip on the ground.

Many people may think that four-wheel drive cars will have stronger ground performance, in fact, they confuse the concept of ground performance, the biggest difference between four-wheel drive cars and two-wheel drive cars is: FF models will understeer because of the idle wheels and deviate from the corner, while FR models will flick their tails, and four-wheel drive will not have the above problems because the power distribution of each wheel is automatic, which is related to the tracking performance of the car, not the ground performance.

Four-wheel drive and two-wheeled versions.

On the contrary, the four-wheel drive and two-wheeled versions of the same car tend to have stronger acceleration and ground-hugging performance than the four-wheel version, the best example is the Audi A4, because the four-wheel drive car is more weight and friction than the two-wheel drive one.

Passive all-wheel drive systems use mechanical transfer units, such as the geared torque-sensing differential Audi quattro or the hydraulic transfer case Porsche's 911 turbo, which only intervenes after the wheels have idled. The active all-wheel drive system, on the other hand, intervenes through a computer-controlled multi-disc clutch, such as Shanghai Volkswagen's 4 Motion, which continuously collects data such as tire speed and throttle size, and distributes torque before the tire idles.

Wheel slippage. When a two-wheeled car (front or rear) has an idling tire spin, there is only one remedy, which is to reduce the driving force of the engine, and the driver can only achieve this goal by draining the fuel, or the driving computer controls the reduction of the throttle. Four-wheel drive cars are different, you can refuel as you like, and the power will be automatically distributed to each wheel through the electronic system, which can more effectively prevent wheel slippage.

Four-wheel drive system (4WD-4 wheel drive system), 4WD system is to change the driving force of the engine from the two-wheel drive of the 2WD system to the four-wheel drive, and the reason why the 4WD system is included in the active safety system is mainly that the 4WD system has a better application efficiency of the engine drive force than the 2WD, and achieves better tire traction and steering force. Therefore, in terms of safety, the 4WD system has a better application of tire traction and steering force, resulting in good driving stability and traction, in addition to the 4WD system, which has more off-road performance that 2WD does not have. 4WD can be roughly divided into short time (part time 4WD) and full time (full time 4WD) four-wheel transmission system, short-term four-wheel transmission system can be selected according to the needs of the driver, two-wheel transmission or four-wheel transmission, this transmission system is a more traditional 4WD system, from the point of view of off-road, this transmission system when the four-wheel drive mode is selected when the front and rear wheel train is directly connected, can ensure the driving force output of the front and rear wheels.

Therefore, this system is a 4WD system suitable for off-roading. The other is the full-time 4WD system, this system does not need to be operated by the driver, the vehicle is always in the four-wheel drive system, this system can be distributed through the front and rear drive force, can achieve a more perfect tire drive force and steering force optimization configuration, is a high-performance transmission system, in addition to the configuration of the general off-road jeep, is also often used in some high-performance coupes.