Technology competition at the Shanghai Auto Show: Hybrid VS pure electric

At present, new energy vehicles are mainly divided into three categories: hybrid vehicles, pure electric vehicles and nuclear fuel cell vehicles. The Shanghai Auto Show, which opened on April 19, 2011, focused on the concept of "innovative future", so this auto show also became a collective appearance of new energy vehicles. Both electric and hybrid vehicles had new cars released.

What is a hybrid car

As the name implies, a hybrid vehicle is a vehicle whose power system consists of two parts: fuel power and electric power. Fuel power refers to a power system that uses a traditional internal combustion engine to burn gasoline or diesel to release chemical energy to drive the vehicle forward. Electric power refers to an electric system that uses an on-board battery to provide electricity to assist the fuel power system.

The Fit Hybrid is a mid-size hybrid

Hybrid vehicles are divided into four types: mild hybrid, medium hybrid, heavy hybrid, and plug-in hybrid. Strictly speaking, mild hybrid is not considered hybrid because it is still powered by fuel. Compared with traditional cars, mild hybrid has an automatic start-stop system, which reduces emissions and fuel consumption, so many car manufacturers promote it as hybrid.

The power system of a mid-size hybrid vehicle involves an electric motor, but the motor is only an auxiliary to the gasoline engine and cannot work independently.

Lexus CT200h Hybrid

In this way, heavy-duty hybrid is the mainstay of the hybrid family. The Lexus CT200h, which debuted in Asia at the auto show, is a representative of heavy-duty hybrid. Its electric motor can work independently, and the maximum power of the electric motor of such a heavy-duty hybrid vehicle is generally higher than one-third of the maximum power of the fuel engine.

However, heavy-duty hybrid vehicles also have a disadvantage, that is, the fuel engine has to use part of its power to charge the battery. Therefore, Toyota and many other companies have developed plug-in hybrid vehicles on this basis. The new generation Prius and Volvo C30 plug-in hybrid concept car, which were first launched in China at this auto show, are both representatives of hybrid vehicles. In addition, don't forget the domestic brands. Although BYD F3DM is a frequent visitor to previous auto shows, its unique iron battery technology can still be used for a long time.

Electric vehicles are a dazzling sight at the auto show

As for what electric cars are, I don't think I need to elaborate too much here. At this auto show, electric cars from various manufacturers were on display one after another. BMW Active E, Nissan Leaf, Ford Focus Electric, and Golf Green-E-Line were all the focus of attention at this auto show.

Fence-sitter - Extended-range electric vehicles

At the auto show, Shanghai GM also showed the Chevrolet VOLT extended-range electric vehicle. In fact, this car is a fence-sitter between hybrid vehicles and pure electric vehicles. The reason why Chevrolet calls the VOLT an electric vehicle is that the car is indeed driven only by electricity, but Chevrolet also installed an engine on this car. This traditional internal combustion engine is specifically used to charge the battery. It is not started at ordinary times, and only works when the battery power of the VOLT is insufficient.

Technical structure analysis

BMW Active E structure diagram

From the perspective of technical structure, electric vehicles have the simplest structure, and only three assemblies are needed to solve the problem. Hybrid vehicles are the most complicated, and they not only have a traditional engine and gearbox, but also an electric motor. Of course, this is not the most troublesome thing. The most fatal problem of hybrid vehicles is how to handle the switching between the electric motor and the gasoline engine.

The usual solution in the industry is to install two clutches in the car, one to control the power output of the motor and the other to control the power output of the gasoline engine. Currently, the most advanced form of hybrid power, plug-in hybrid power, also requires an additional charging device.

Chevrolet Volt structure diagram

Obviously, the more complex the structure, the more likely it is to fail. The Americans came up with a solution in this regard, which is to only let the gasoline engine generate electricity. Therefore, the Chevrolet Volt, which was supposed to be a hybrid car, has turned into an electric car.

Performance Analysis

BMW Active E

At this auto show, BMW Active E made its Asia Pacific debut. This electric car based on the BMW 1 Series Coupe is equipped with an electric motor with a maximum power of 125KW and a maximum torque of 250n·m; the vehicle has a curb weight of 1.8 tons, and can accelerate from 0 to 100KM/h in just 9 seconds, with a maximum speed electronically limited to 145KM/h. If BMW's data is not exaggerated, then the acceleration capability of BMW Active E is already amazing. The reason why BMW Active E can achieve such an impressive result is inseparable from the characteristic that the electric motor can instantly output the maximum torque when starting.

To be honest, power comparison is not very meaningful, because hybrid cars are designed for energy saving, and power is largely ignored. Except for the abnormal Ferrari 599 hybrid concept car, the power performance of most hybrid cars is not very good. However, with the help of gasoline engines, the top speed of hybrid cars is often higher than that of electric cars.

Practicality Analysis

Nissan Leaf electric cars have two power connectors

At present, electric vehicles are absolutely zero-emission, but battery capacity and reliability are still technical bottlenecks for electric vehicles, which has led to the fact that the driving range of electric vehicles we see now does not exceed 100 kilometers. In addition, how to charge pure electric vehicles and how to settle electricity bills will also be a big problem.

Chevrolet Volt gasoline engine

In addition, we have to talk about extended-range electric vehicles. Chevrolet's official information says that Volt can add an additional 450 kilometers of driving range. In fact, Chevrolet used the strategy of "avoiding the real and attacking the virtual" in the Thirty-Six Stratagems. Chevrolet's official information does not tell us where the extra 450 kilometers of driving range comes from?

According to official information, the Chevrolet VOLT extended-range electric vehicle has a 45-liter reserve fuel tank. If the 450-kilometer driving range is achieved by the engine burning 45 liters of gasoline, then the fuel consumption of the vehicle in the extended-range state will be as high as 10 liters per 100 kilometers. In this way, the Chevrolet VOLT's engine is only for emergency use, and the owner must not fail to charge the battery just because it has an engine.

Summarize

Comprehensive technical structure, performance analysis, and practicality analysis show that among the many types of new energy vehicles, hybrid vehicles are more complex in design, but have more advantages in performance and practicality. In the recent period, hybrid vehicles are the most suitable for the public among new energy vehicles.