Pure electric has been the majority but experts insist on mixing

The Ministry of Science and Technology promulgated the "National Twelfth Five-Year Plan for Science and Technology Development", which puts emphasis on the full implementation of the "pure electric drive" technology transformation strategy and the implementation of the new energy automotive technology industrialization project. However, at the product level, there are still experts and powertrain manufacturers insisting on the "mixed" technology route, or that these experts (manufacturers) insist that the "hybrid" technology route has its advantages and cannot be lost. What's the reason?

I. Distribution of New Energy Automobile Products in 2017

In 2017, the number of automobile sales in China was 28.887 million, of which 777,000 were new energy vehicles. The breakdown was as follows:

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The development of new energy vehicles in China has been developed to the present day, and the technical route has not yet been completely transformed into a pure electric drive. The plug-in hybrid power is given at the policy level. After all, it is hybrid power. The number of plug-in hybrids was 16% in 2017, 60% for pure electric passenger cars, and 14% for plug-in hybrid passenger cars; 24% for pure electric commercial vehicles, plug-in hybrid commercial vehicles It is 2%. The above shows that hybrid vehicles still have relatively strong vitality, especially plug-in hybrid passenger cars.

Second, the plug-in hybrid scheme is more, but basically has converged to the coaxial hybrid

(1) The plug-in coaxial coaxial hybrid scheme is shown in Figure (1). In principle, there are engines, axles or traditional axles. They have taken away traditional transmissions and traditional axles and used power electronic components to make

Figure 1 Plug-in coaxial hybrid scheme

Plug-in meaning is reflected in the matching power battery (super capacitor) can accept the charge outside the car. Its technical difficulties are:

1 The difficulty on the hardware is: the integration of the IGS motor, electronically controlled automatic clutch, and main drive motor;

2 The difficulty on the software is: There are 2 motor controllers. If they work together?

(2) Explain the relevant ideas

1IGS motor: It is a car starter and generator integrated directly on the engine's main shaft. The ISG incorporates technologies such as motors, modern power electronics, digital signal processing, and modern control. It combines the start-up and power generation functions of a conventional car, with outstanding start/stop control, good energy regeneration, and strong power assistance. It is an internationally recognized direction for the development of traditional automotive, hybrid and future electric vehicle engine components.

2 electronically controlled automatic clutch: abbreviation ACS (Automatic Clutch System) is the clutch through mechanical, electronic, hydraulic and other ways to achieve automatic control.

3 Main drive motor: A motor that is connected to the rear axle to produce the driving force of the car.

Third, plug-in coaxial hybrid program advantage analysis

The principle of plug-in coaxial coupling and actual product correspondence is shown in Figure (2). The advantages of the plug-in coaxial hybrid scheme are as follows:

Figure 2 The principle of plug-in coaxial coupling and the actual product

1 is a pure electric drive, the power source is divided into two parts, one part is the engine to provide mechanical power, after the power supply for the main drive motor; the second is the power battery power supply machine;

2 The basic functions of traditional bridges are basically preserved, and vehicle stability and smoothness are guaranteed;

3 The engine is reserved, but the engine power span is less demanded, and the engine is basically maintained in the high-efficiency zone. See (3). The effect of energy saving and emission reduction is visible.

Fig. 4 Curve of different modes

4 dependence on the charging pile, significantly reduced, that is, charging the pile safely, no charging pile can be no hurry.

Third, summary

1 plug-in coaxial hybrid program, a relatively high degree of integration, product stability. This point is very important to the user.

2 plug-in coaxial hybrid program development direction, there are two directions, one is more advanced passenger cars, such as the B-class or more models, the second is more large-scale freight vehicles;

3 The city bus and taxi pure electric technology are basically mature, although there is still more room for improvement;

4 The basic trend of motorization of urban freight vehicles is the axle direct drive scheme.

5 The large-scale diesel freight vehicles with serious automobile pollution, and the use of gasoline engine plug-in coaxial hybrid solutions, are comprehensively improved.