The first model of the Weilai Automobile EP9 finally appeared in London. As the fastest lap (7 minutes and 05 seconds) to brush out an electric car in the North Ring of Nürburgring, Germany, its appearance has attracted countless eyes. However, the current limit of 6 units, the price of 1.2 million US dollars each, is also discouraged by ordinary people. Whether it is an electric sports car or a high price, it is still far from us, but in reality there is such a "compromise" method - the hybrid model can let us experience it. Today, let's talk about the plug-in hybrid.
Hybrid vehicles allow a part of the electric motor to participate in the engine work, and convert the electric energy into mechanical energy to replace the effect of a part of the oil, thereby achieving the purpose of fuel saving. This is also a step in the transition from traditional cars to new energy vehicles. The plug-in hybrid car, the reason why there is a "plug-in" word, is mainly to introduce an external power supply, to provide continuous power through the external charging of the car battery, so that the electric energy plays a more important role in the car driving The role of energy saving and emission reduction.
A Plug-in Hybrid Vehicle (PHV) is simply a type of car between an electric vehicle and a fuel vehicle. Its hybrid drive principle and drive unit are the same as electric vehicles. There are batteries, motors and control circuits for electric vehicles, and the battery capacity is relatively large, and there is a charging interface. The only difference is that the car is equipped with an engine. It also has the engine, transmission, transmission system, oil circuit, fuel tank and other modules of traditional cars.
In the plug-in hybrid vehicle, two complete power systems of electric vehicles and fuel vehicles are integrated. Therefore, the cost of the plug-in hybrid vehicle is relatively high and the structure is relatively complicated. This is also the reason why the price of plug-in hybrid models on the market is generally higher. In addition, due to the fact that many accessories will cause their own weight, there are some disadvantages compared with other models. However, before the popularization of charging piles or breakthroughs in battery technology, plug-in hybrid vehicles will still exist for a long time.
There are a lot of plug-in hybrid vehicles on the market, and each manufacturer will manufacture plug-in hybrid vehicles based on their own capabilities and product patents. Generally speaking, plug-in hybrid vehicles are mainly divided into three types: parallel type, hybrid type and extended program. Products of different routes have their own advantages.
Parallel plug-in hybrid
There are two sets of drive systems in this type of plug-in hybrid car, most of which are based on the traditional fuel car, which is added with electric motor, battery and electric control. When the vehicle is driving, the motor and the engine jointly drive the wheel.
Therefore, the advantage of the parallel plug-in hybrid car is that the motor and the engine jointly drive the wheel, and there is no problem of power waste, such as motor power 50 kW, engine power 100 kW, as long as the transmission system can withstand, the vehicle power is 150 kW. In pure electric mode, the car is quiet like a pure electric car, but the electric motor cannot generate electricity and drive the wheels at the same time.
However, this mode has a weakness. In the parallel mode, the engine speed is directly related to the wheel, the speed is high, the engine speed is fast, the noise is very loud, and the comfort is poor. BYD once wanted to add a gearbox directly to the engine and shaft, but at the time BYD did not have gearbox technology and could not do it. F3DM can only be studied, try to avoid this problem with the series mode, so F3DM only has the characteristics of fuel-saving, and there is no advantage that the hybrid vehicle accelerates quickly.
Qin's motor is added to the output of the gearbox. As long as the reducer can withstand, all the power can be used. The gearbox does not need to be expensive, so the power of the whole car can be increased. However, this mode also has disadvantages. The motor does not pass through the gearbox, only fixed deceleration. At high speed, the efficiency of the motor at high speed will decrease, and the torque supplied to the wheel will drop sharply.
However, parallel plug-in hybrid models also have shortcomings. In the hybrid mode, the engine can not always guarantee to work at the optimal speed. The fuel consumption is relatively high during the driving process. Only when the traffic jam occurs, the self-contained engine starts and stops. The fuel consumption will be low when functioning. And it is precisely because the parallel plug-in hybrid vehicle has only one motor that cannot generate and drive the wheels at the same time, so the working condition of the engine and the motor driving the wheels together cannot last. When accelerating, the energy of the battery will quickly run out and turn into the engine's separate drive mode.
Plug-in hybrid: Analyze mixed and extended programs
Hybrid plug-in hybrid
As with parallel plug-in hybrids, this mode also has two drive systems, but the difference is that there are two motors in the hybrid mode. One motor is only used to drive the wheel directly, and another motor has a dual role: when extreme performance is required, the motor can act as a motor to directly drive the wheel. The vehicle power is the sum of the power of the engine and the two motors; when the power is insufficient When it acts as a generator, it charges the battery.
Therefore, the hybrid plug-in hybrid has the advantages of quiet electric vehicle and low use cost in the pure electric mode; the engine can be controlled at the optimal speed at all times, and has the characteristics of low fuel consumption, low noise and small vibration; Under the two motors and one engine can work at the same time, the three "harmonious", with good start performance and acceleration performance, is an ideal combination.
But relatively speaking, the main components such as two motors, engines, and gearboxes are indispensable, and the matching control circuit, battery, transmission system, and oil circuit are also the same. This combination makes the overall cost higher. For other types of plug-in hybrids, the total weight of the car will be larger. At the same time, because of the multi-control motor and an engine, and the mode according to the working conditions, the control system is relatively complicated and the investment will increase.
The hybrid plug-in hybrid also has a mode in which the "part-time" motor is placed together with the engine, and the other pure motor is placed separately. The representative of this model is the Porsche 918, the BMW i8.
Extended range plug-in hybrid
This type of plug-in hybrid, although nominally attributed to plug-in hybrids, is strictly an electric vehicle. Because there is only one set of electric drive system in the car, including motor, control circuit and battery. The electric motor of the extended-range plug-in hybrid vehicle directly drives the wheels, and the engine is no longer the driving wheel, but is used to drive the generator to charge the battery. Since the engine does not drive the wheels directly, there is no need for a gearbox. In other words, this is equivalent to loading a generator on an ordinary electric vehicle.
At the same time, because the engine does not directly drive the wheel, the engine speed is not directly related to the wheel speed and the vehicle speed. Through the optimization of the control system, the engine can always work at the optimal speed. Even when the charging is inconvenient, the fuel consumption in the traffic jam in the city is also compared. Low, engine noise can also be controlled very small.
However, also because the engine and the generator do not directly drive the wheel, there is a partial loss of power during the energy transfer. For example: an extended-station hybrid electric vehicle with an engine power of 50 kW, a generator power of 50 kW, and a motor power of 100 kW. The vehicle carries a total power of 200 kW engine and motor, but the power to drive the wheels is only 100 kW.
In high-speed road conditions, fuel consumption is rather high. This is because under high-speed road conditions, if the engine directly drives the wheels, it can always work in the best working mode, and the extended program plug-in hybrid has one more conversion process, and the conversion itself consumes energy, resulting in higher fuel consumption.
Summary: In the current situation of environmental issues, it is particularly important to study new energy sources that are more environmentally friendly. The recent big moves of many "electric cars" can glimpse its trend. However, because the technology is not mature enough, and the supporting facilities and the environment are not perfectly matched, the end point of the new energy vehicle is still very far away from us, and the hybrid car is a good role in the role of “intermediate rest station”. These types of plug-in hybrids have their own characteristics, and the most reasonable and cost-effective cost will be high; the low cost and some fuel-saving effects are not so prominent. If you choose, the benevolent sees the wise and sees wisdom.
