Snow is always an interesting thing in the south, but the snowflakes in the sky also cause headaches for those who own cars. They are embarrassed on the road and may even have safety accidents.
A car that can walk leisurely in the snow relies on its magic weapon—the four-wheel drive system. Everyone is familiar with the four-wheel drive system, such as Audi’s quattro, Mercedes-Benz’s 4matic and BMW’s x-Drive, etc., are all four-wheel drive systems that everyone is familiar with.
However, no matter which company’s four-wheel drive system can’t escape the three big diamond covers of “timely four-wheel drive, part-time four-wheel drive, and full-time four-wheel drive”, then what is the difference between them?
Timely four-wheel drive
Simply understood literally, it refers to a four-wheel drive system that is only available when appropriate, and is still a two-wheel drive drive system in other cases. Due to the structural characteristics of timely four-wheel drive, it is more suitable for models equipped with front-mounted engine and front-drive platform, which makes many SUVs or four-wheel drive cars based on this platform have the ability to assemble four-wheel drive systems.
Of course, don’t drive it to muddy land, swamps and other harsh environments just because there are 4WD or 4*4 signs on the rear of the car. Urban SUVs with timely four-wheel drive are mostly front two-wheel drive. Grip is the same as a front-wheel drive car.
Thanks to the structural characteristics of timely four-wheel drive, it can be easily mounted on many models; at the same time, because of its structural characteristics, it cannot transmit more than 50% of the power to the rear axle. When dealing with bad roads, timely The physical structure limit of four-wheel drive is low.
Generally speaking, the timely four-wheel drive structure is relatively simple, the cost is relatively low, and the fuel burden on the car is not large, but it can play a general role and is suitable for auxiliary driving needs in daily use. Therefore, like X-Trail, RAV4, Urban SUVs such as CRV and Koleos are all equipped with timely four-wheel drive systems.
part-time four-wheel drive
It is a four-wheel drive system that can be manually selected between two-wheel drive and four-wheel drive. According to the road conditions, the two-wheel drive or four-wheel drive mode can be adjusted by turning on or off the transfer case. Driving an SUV is a more common driving mode.
The feature of the time-sharing four-wheel drive is that it can actively control the state of the four-wheel drive and two-wheel drive of the car. When passing through muddy land, swamps and other harsh roads, the car that is switched from the transfer case to the four-wheel drive mode has enough power for each wheel. , high passability.
At the same time, since the mode must be switched manually, the technical requirements for the driver are relatively high, and the timing of switching needs to be judged. Moreover, some part-time four-wheel drive vehicles are not equipped with a central differential, which makes them unable to drive on paved roads. Using the four-wheel drive system, especially on curves, cannot turn smoothly, and can only be applied for short periods of time in extreme situations.
Generally speaking, part-time four-wheel drive is a necessary equipment for hard-core off-road vehicles. It has a simple structure, high stability, and durability, but it is used in extreme conditions, so it is only equipped on hard-core off-road vehicles.
full-time four-wheel drive
A drive system in which all wheels move independently at any time the car is in motion. Compared with timely four-wheel drive and part-time four-wheel drive, full-time four-wheel drive is more thorough. It is independent four-wheel drive at any time and anywhere. Because of its full-time four-wheel independent movement, full-time four-wheel drive vehicles are driving In the process, it has very good road adaptability.
And many systems can freely distribute the driving force of the front and rear axles. Whether it is a normal road or a muddy and slippery road, it is in a four-wheel drive state, which can provide better driving performance.
Nissan GT-R, Golf R, and Subaru Impreza are all equipped with a full-time four-wheel drive system. In addition to being equipped with a full-time four-wheel drive system, they also have a feature, that is, people who buy this car are not bad …In addition to the high cost of the full-time four-wheel drive system, it also consumes more fuel. After all, the four wheels work at the same time and consume more power.
In general, the full-time four-wheel drive can bring the best driving stability. It will be more neutral than the two-wheel drive model, and can better avoid the understeer of the front-wheel drive and the oversteer of the rear drive. However, The high cost and the high fuel economy in the later period are all pain points for the wallet.
When buying a car, I always encounter the trouble of whether to spend tens of thousands more to buy a four-wheel drive version. The choice of part-time four-wheel drive and full-time four-wheel drive models is obvious. Either you don’t buy it, or you buy it because of it. Therefore, the timely four-wheel drive caught in the middle has become the most tangled object.
In fact, it is very simple. For the north where snow is inevitable in winter, or the road conditions that often cross harsh environments, timely four-wheel drive is still very practical. Although the passing ability is not strong, compared with two-wheel drive, timely four-wheel drive is enough for daily life. used. However, in the south where there has been no snow for many years or only on paved roads, the role of timely four-wheel drive is not obvious. After all, two-wheel drive can meet the use, and timely four-wheel drive is more tasteless, and the purchase is not meaningful.
Source of pictures and texts: Xiaoxin Shuoche’s original article.
