Who will be the future of the power drive system?
Which way does the future drive system work? This is a question that many people care about. The answers of people in the automotive industry are divided into two camps. Some people say that the hub motor represents the future direction of development. This breakthrough technology has been around for a long time. However, there has been no production model for the production. Some people say that the dual-motor dual transmission is the mainstream power drive system in the next decade. This technology is to re-understand and improve the existing traditional technology, and many vehicle manufacturers have adopted this power drive system.
Who can handle the wheel hub motor and the dual-motor dual-transmission in the future power drive system competition?
■The advantages of the hub motor and the short board are outstanding
The shorter the power transmission path and the higher the efficiency of use, this is the consensus of automotive experts. The advantage of the hub motor is precisely reflected in this aspect. Xu Dong, head of Asia Pacific at Protean in the UK, said: "The hub motor integrates the drive, transmission and braking devices in a small space and is very compact. The power acts directly on the wheels, omitting the clutch, transmission, drive shaft, and poor Transmission components such as speeders and transfer cases greatly improve power efficiency."
At present, the traditional car can not achieve zero-radius steering and lateral driving, but the hub motor can do it, making the parking operation easier and saving urban parking space. An insider said: "After the large-scale use of the hub motor, the side-by-side parking in the driver's license test may be cancelled."
The advantages of the hub motor are obvious, and the short board is also outstanding. Cai Wei, a refined electric CTO, said: "The hub of the traditional car is separated from the suspension by a spring. The hub motor is integrated with the wheel to increase the unsprung mass and affect the handling performance of the vehicle, especially the stability of the curve."
The hub motor is close to the road surface and is in high speed operation with very high sealing requirements. Xu Xiangyang, a professor at Beijing University of Aeronautics and Astronautics, said: “There are many rains in the south. Even if walking on urban roads, the hub motor often wades. The static sealing is less difficult, and it is difficult to achieve sealing under high-speed operation.”
Traditional cars enhance the comfort of the vehicle through two sets of shock absorbers, such as tires and springs. The wheel hub motor relies only on tire damping, which brings reliability problems. Cai Wei said: "The tire's shock absorption capacity is limited. When encountering uneven roads, the hub motor and the wheel wall are prone to hard collisions and reduce the reliability of the hub motor."
High-speed parts are inseparable from lubricating oil to reduce frictional resistance. The hub motor is very compact, and the addition of lubricating oil and lubrication between parts are difficult. Xu Xiangyang said: "High-speed parts will consume more lubricant. The gap between the hub motors is very small, and it is difficult to store the lubricating oil."
The motor is characterized by high speed and low torque. The hub motor eliminates the need for a transmission and other devices. The motor controller adjusts the speed. This makes the hub motor use narrower and is difficult to use on commercial vehicles and special vehicles. Even if used on a passenger car, the climbing performance is not good.
At this year's Beijing Auto Show, the reporter asked the relevant personnel of the Asia-Pacific shares on these issues. They only told reporters that the Asia-Pacific shares of the hub motor used a water-cooling system to solve the heat dissipation problem. Other questions did not answer the reporter.
The Asia Pacific shares have set up the hub motor business unit, and are ready to vigorously promote research and development and mass production. The reporter also learned that Protean in the UK cooperated with a domestic company to build a hub motor factory in Tianjin. The reporter saw that the construction site had set up a fence in Tianjin.