What are the five driving modes of cars?

Pre-drive: This drive mode is the most common one at present. Its advantages are: because the engine is close to the transmission shaft, the transmission efficiency of the front drive is higher, and there is no transmission shaft of the rear drive, so the front drive generally has no middle protrusion (because of the exhaust system), and the rear seat floor is smoother; In addition, the cost of the front drive is lower and the maintenance is easier than that of the rear drive, so most of the front drives are low-priced models such as mini-cars, compact cars and mid-size cars. Disadvantages: because the engine and transmission system are basically concentrated in the front of the car, there is a feeling of "top-heavy", and there will be understeer under fierce control; When accelerating rapidly, the adhesion of the front drive wheel is reduced due to the backward shift of the center of gravity, which is more likely to cause idling and slipping than the rear drive wheel; \ x0d \ x0d \ front and rear drive: Its advantages are: uniform axle load distribution, that is, the front and rear weight of the whole vehicle is relatively balanced, and the handling stability is good. The front and rear wheels perform their respective functions, and the steering and driving are separated, thus reducing the burden on the front axle and the rear axle. Similarly, when accelerating sharply, the center of gravity moves backward and the adhesion of the rear wheel is strengthened, which is more conducive to the perfect start acceleration (unless the accelerator is stepped on too hard); There will be a situation of oversteering when driving violently, but it is more fun for most people to drive. Disadvantages: the structure is complicated, and the addition of the transmission shaft also increases the power loss. Similarly, due to the influence of the transmission shaft, there is a protrusion in the middle of the car body, which affects the leg space inside the car; The maintenance cost is higher, so now the rear-wheel drive is generally mid-to high-end cars, or cars that emphasize driving. \x0d\\x0d\ rear drive: This drive mode is the most unbalanced among the five, and only Porsche 9 1 1 is using this drive mode now. Because of the rear engine, most of the weight is concentrated in the rear of the car body, resulting in a serious imbalance in the weight distribution of the front and rear axles of the car body. Now the front-to-rear weight ratio of 9 1 1 is about 38: 62. RR has the advantages of reducing indoor noise, facilitating the internal layout of the car body, compact structure, no bulky transmission shaft and no complicated front wheel steering and driving structure. Disadvantages are: the load on the rear axle is large, which will lead to an excessive steering tendency opposite to FF, and the tail is too active, which requires higher driving skills for drivers. \x0d\\x0d\ central rear drive: At present, there are two types of central rear drive. One is that the engine is placed between the front axle and the rear axle, and the rear wheel drive is adopted at the same time, which is similar to the arrangement of F 1 racing car; There is also a "front center engine", that is, the engine is located in the front of the car body, but behind the front axle and in front of the passenger compartment, which is similar to FR, but can achieve the same ideal axle load distribution as MR, thus improving maneuverability. MR has the advantages of uniform axial load distribution and neutral handling characteristics. The disadvantage is that the engine occupies the cockpit space, which reduces the space utilization and practicality, so MR is mostly a sports car that pursues handling performance. \ x0d \ x0d \ Four-wheel drive: Four-wheel drive is the most perfect drive form among all drives at present, which can be divided into four types: part-time 4wd, full-time four-wheel drive, permanent four-wheel drive and all-wheel drive (AWD). The other four-wheel drive is divided into front four-wheel drive, middle four-wheel drive and rear four-wheel drive according to the engine layout. Mid-mounted four-wheel drive: This drive mode is the most perfect of all drive modes. Because the engine is centered, the front-to-rear weight ratio of the vehicle is the most balanced. In addition, the four-wheel drive layout has less power transmission loss, which is very beneficial to the development of vehicle power. Therefore, the middle four-wheel drive layout is generally used for super sports cars. Front four-wheel drive: this drive mode is mainly used for off-road vehicles, SUVs and four-wheel drive cars/wagons to improve the passing performance and stability of vehicles; Rear four-wheel drive: This method is currently only used on Porsche 9 1 1Turbo. On the whole, the advantages of four-wheel drive are: improving the passability and stability of the vehicle, the steering process is relatively stable, and generally there will be no understeer or oversteer. Disadvantages are: the structure of the four-wheel drive system is more complicated, and it will increase the weight of the car body, resulting in increased fuel consumption and higher maintenance costs.