Abstract: Planning and Implementation of Electric Drive System for SAIC Passenger Vehicle

I.  Sales Status of SAIC Passenger Cars
II. The Present Situation of the Industrial Chain of the Third Electricity Industry
III. PHEV/BEV Technical Route and Specific Scheme

Over the past eight years, China’s new energy vehicles have witnessed leapfrogging development. From January to November, the sales of new energy vehicles reached 1.03 million vehicles, accounting for 60% of the global sales during the same period. It is expected that the sales of new energy vehicles in China will reach 1.6 million in 2019. China has become the most important new energy vehicle market in the world.

Nowadays, new energy vehicles have been chosen and loved by more and more consumers. Automobile products will be transformed from a single vehicle to intelligent mobile space. Automobile enterprises will upgrade from traditional manufacturers to integrated suppliers of travel services and products. In 2018, SAIC achieved sales of more than 140,000 new energy vehicles, including nearly 100,000 self-owned brand passenger cars, doubling sales for five consecutive years. The first generation EDU technology of electric drive gearbox independently developed by SAIC won the second prize of national scientific and technological progress in early 2018 because of its originality, efficiency and reliability. In 2018, SAIC achieved sales of more than 140,000 new energy vehicles, including nearly 100,000 self-owned brand passenger cars, doubling sales for five consecutive years. The first generation EDU technology of electric drive gearbox independently developed by SAIC won the second prize of national scientific and technological progress in early 2018 because of its originality, efficiency and reliability.

1. Construction of Three Electricity Industry Chain
While building competitive products, SAIC has also established a complete system of software and hardware development for the three-Electric power plants, and built a key component industry chain as the center. SAIC has jointly established UABS and CATL Ningde New Energy, jointly manufactured IGBT modules with Infineon in China, and cooperated with Huayu Automobile and Magna in the field of electric axles. Committed to providing high-quality services in the whole industry, to provide technical support for the technological progress and rapid development of China’s new energy automotive industry.

2. Two New Energy Routes and Planning
Looking to the future, it is more important to base on the present situation. SAIC should take the advantage of the current situation in the new energy drive system and develop the system and product layout of PHEV and BEV. Accelerate the speed of product upgrading and enhance the competitiveness of products. On PHEV, we have been devoting ourselves to the research of electromechanical coupling control technology since 2009. By 2011, we will complete the development of EDU G1 and further reduce energy consumption and improve performance in the process of continuous optimization and improvement. It has been applied to e550, eRX5 and other types of vehicles. At the same time, the development of EDU G2 was started in 2015, and the electromechanical coupling configuration of single motor, single clutch and multi-gear interactive power shift was put into operation in April 2019. The configuration can realize pure engine driving, pure electric driving, dual-source mixing, idle charging, driving charging and other working conditions, and has dual power sources to compensate each other. Interactive switching of multiple gears can meet the requirements of speed and torque under different working conditions. When braking, energy recovery is carried out to maximize the economy of the hybrid system. On the basis of EDU G2, EDU G2 plus is further upgraded and developed. It not only extends to engine platforms above 1.5T, but also integrates motor controllers to reduce Z-direction height, optimize envelope volume, and reduce cost, so as to make technical reserve for the next generation of products in multi-platform applications. On EV, aiming at architecture application, the platform development of 80kw, 120kw and 150KW E1 series electric axles is carried out. On the basis of E0 electric drive system, the performance of E1 series electric axles is further improved, the efficiency range is optimized, and the deep integrated inverters are designed. At the same time, the cost is reduced, and the friendly boundary conditions are provided for the whole vehicle application. The E1 series will be successively SOP in 2020, serving the next generation of products.
Influenced by the policy and market in 2019, the car market has generally declined. With the deterioration of policy support, new energy vehicles can only win the trust of consumers by improving their product competitiveness. SAIC is fully prepared for the arrival of the era of no subsidy in terms of product quality and censurability.

PHEV next generation:EDU G2 technical highlights

High performance
1. Innovative P2.5 configuration, single motor lateral arrangement, compact structure, no power interruption in mixed mode shift.
2. Six gears of engine and four gears of motor are set to realize the operation of motor and engine in high efficiency range under various working conditions.
3. Integrated Hair-Pin active oil-cooled motor to achieve high performance output of 90 kw/230 Nm motor.
4. Dry single clutch and its shock absorption system can realize 250 Nm high efficiency and high torque transmission.
5. Efficient electrically selected shifting system, backing and shifting can be completed in the same location, the limit shifting time is less than 200 ms.
6. The ultimate response speed of clutch system is 175 ms, and the traditional DCT structure is generally larger than 250 ms.

High Efficiency and Low Consumption
1. Compared with DCT electro-hydraulic energy conversion, the efficiency of electrically selected gear shifting mechanism is higher.
2. After shifting, the locking pin locks the gears mechanically, and no other power locking mechanism is needed to consume electricity.
3. The maximum efficiency of mechanical transmission in electromechanical coupling system is more than 94%.
4. Dry clutch works without towing loss.
5. There is no friction loss in clutch switching during single clutch shifting, and the energy consumption per unit mileage of driving DCT is less than 50%.

System streamlining
1. Through gear multiplexing technology, only 18 gears + 4 synchronizers can realize multi-gear combination of engine 6, motor 4 and mechanical R.
2. The cost of single clutch is reduced by about 40% compared with DCT, and the design life of single clutch is 240,000 km.
3. Clutch sliding can start the engine without BSG motor.
4. Shift actuator only needs two motors to control four synchronizers, without complicated valve body structure. Design life is 240,000 kilometers, maintenance-free.

High safety
1. When shifting gears, the single clutch is opened to avoid the risk of dynamic interference caused by the interaction of two clutches such as DCT.
2. The clutch can open itself and cut off the power of the engine under special conditions.
3. The shift actuator ensures that no misalignment is made by mechanical locking of the pointing and positioning shafts.
4. The shift system learns from the synchronization point and the maximum shift distance when the vehicle is running normally and updates it in real time.

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