Many people may have learned about electric vehicles and hybrid cars in recent years. In fact, the two technologies have been developed for a long time. Electric vehicles have gradually entered the market and been accepted for almost 10 years due to the three power and cost issues. And hybrid cars have been around for more than 20 years.
The reason why the acceptance in the Chinese market is far lower than that in foreign markets, the root cause is that the popularity of cars in China has only begun in the past 10 years, and users need to be able to afford and understand the car. This has led most users to consider the “big and full” feature when selecting a vehicle to cover all possible usage scenarios.
When consumers began to return to rationality, the purchase of cars in addition to brand influence, practical and easy to use has almost become the only standard, so electric cars and hybrid cars gradually entered the field of Chinese consumers.
The advantage of electric vehicles lies in the characteristics of the motor power system itself, quiet, smooth running, fast speed increase, low charging and maintenance costs, large space inside the car, etc.; and the shortcomings are also very obvious. At present, infrastructure construction cannot keep up. No matter how fast the charging speed is, the shortage of the charging station will still cause inconvenience in use.
So you want to save energy and money, and don’t worry about long-distance travel without a charge. Hybrid models have become the best choice.
How to mix and mix
Although hybrid cars are called hybrids, in fact, there are many types of hybrids to achieve different effects. According to the structure, according to the motor position, it can be divided into P0~4 kinds of structures, and different structures have different characteristics.
Modern cars are basically equipped with a small motor(inverter), connected to the front end of the engine through a belt, the engine drives the motor to generate electricity, charge the battery and provide power to the vehicle electrical appliances. The P0 structure is to transfer a small motor to a larger motor with a slightly larger battery.
The advantage is that when the engine is temporarily shut down, (slow parking, etc.), using the battery power to drive the mechanical compressor of the air conditioner, provide Cold air function. The disadvantage is that because of the belt connection, the transmission efficiency is very low, so it is almost impossible to provide the engine with increased power, and the kinetic energy recovery effect is also very general. This structure is mostly used in low voltage (12~25V micro-mix, 48V light mix), which is an automatic start-stop service, which has little energy saving effect. .
(SQ7 TDI uses P0 structure)
P1 hybrid is improved on the structure of P0, and the motor and engine are transformed into one. The conventional flywheel is transformed into a motor, and the crankshaft that the engine rotates is used as the rotor of the motor, that is, as long as the engine is running, the motor is running.
The advantage is that since the flexible connection is changed to a rigid connection, the transmission efficiency is much higher. In addition to supporting the engine start-stop and energy recovery functions, the engine output can be replenished according to the driver’s needs, and the kinetic energy is When recycling, it is even possible to apply electric energy through the motor to help increase the braking force and improve safety. However, the disadvantage is that since the motor and the engine are integrated, it is impossible to use the motor alone, that is, it cannot be driven purely, and when the kinetic energy recovery and the neutral gliding, the crankshaft must follow the rotation, wasting the kinetic energy and causing the vibration. And noise is generated. This structure can be applied not only to low voltage due to variations in motor size and transmission efficiency.(12~25V micro-mixing, 48V light mixing) , can also be applied to the 100~200V medium-mixing system, which is slightly more fuel-efficient than the P0 structure.
(Honda Insight, P1 structure used)
Therefore the P2 structure appeared. Similar to the P1 structure, the P2 motor is also between the engine and the gearbox, but it is not integrated into the engine. Instead, the two engines are responsible for the engine and the motor, the motor and the shifting. The combination of the boxes, so the P2 can disconnect from the engine and use only the battery for pure electric driving.
The advantage is that the kinetic energy can be consumed by the engine, the electric vehicle effect is achieved in the pure electric mode, and the efficiency is greatly increased when the kinetic energy is recovered. In addition, since the gearbox is adjusted to the torque behind the motor, the motor can be used not to be too large and reduced. Volume and cost. The disadvantage is that because the motor is connected to the gearbox, it needs to be switched to neutral, and the motor will disconnect the output connection, which means that if automatic start and stop is required, the gearbox needs to constantly switch to neutral, which is very troublesome, so the P2 structure will be attached. A P0 or P1 structure is used as the starter motor, so it is often referred to as the “P0P2 system.”
Since this structure incorporates a structure of a clutch, a motor, and a second clutch between the engine and the transmission, the axial dimension is greatly increased, resulting in trouble in the layout of the car. So Schaeffler of Germany introduced the Schaeffler P2 structure, which integrates the first-stage clutch into the motor structure, which not only reduces the layout difficulty, but also realizes precise control of power transmission by electronic control. The most important thing is that this structure is modular, and the OEM can modify the power system and apply it. The P2 structure is much more fuel-efficient than the P1. At present, most hybrid models use this structure, and the battery can travel tens of kilometers for pure electric power (According to battery size), it can meet the subsidy requirements.
(Mercedes-Benz S400 Hybrid, P2 structure used)
The motor of the P3 structure moves further backwards. After the motor is placed in the gearbox, it is connected to the axle. The output is more direct and more efficient. Therefore, it can naturally drive purely and provide greater power. Added, such as Ferrari’s LaFerrari. The advantage is that the structure is easier to change the original power system, which is easier for the design, and since the structure motor is directly connected to the drive shaft behind the gearbox, the motor power requirement is high, which means The increased volume of the motor takes up space, so the structure is mostly used for the rear drive. This structure has no advantage in fuel economy compared to P2, but the transmission efficiency is higher and the power response is faster.
In addition, there is a P3 structure that is a modification of the P3 structure. The motor is integrated into the gearbox. The motor is integrated into one of the shafts through the dual-axis characteristics of the dual-clutch gearbox to realize the P3 structure.
(Ferrari LaFerrari, using P3 structure)
The last one is the P4 structure. The motor and engine are responsible for two different drive shafts, such as the engine front and the motor on the rear axle, and vice versa. The advantage is that the four-wheel drive can be realized without complicated mechanical structure. The disadvantage is that if you switch to pure electric driving, it meansThe switch between the front and the rear drive is not conducive to the overall handling and comfort of the vehicle.
(918 Spyder, using P4 structure)
So the P4 is either plug-in, only the engine is required to start the engine drive, or it is not the mix, the engine is the main, and the other motor is used as an auxiliary. It is also because of this structural mode that a small motor is usually added to the engine side for starting and charging, and even providing partial power. For example, the Porsche 918 Spyder adopts the “P2P4” structure, the front wheel motor is driven, and the rear wheel is the motor plus engine hybrid drive mode. Most of this model is not a major purpose, but provides a strong boost. Of course, compared to conventional fuel vehicles, the fuel consumption is still much lower when the same performance is provided.
“Japanese style”
The two oil crises that occurred in the 1970s caused the US market, which never worried about oil prices, to be eroded by Japanese “fuel-efficient” models. Then in the 1990s, in order to reduce the car’s environmental and public health hazards, California passed the “Zero Emissions Mandate (Zero Emissions Act) It stipulates that among the new cars sold in California in 1998, the zero-emission car should reach 2%, and in 2003, it needs to reach 10%. This is another bill to strengthen the car emission requirements after the mandatory application of the three-way catalyst.
For the Japanese, the lack of resources originally made them feel a sense of crisis at all times, so the market demand for energy conservation and emission reduction coincided with long-term development needs. Therefore, there will be later Toyota Hybrid THS technology, Honda hybrid iMMD technology, etc., so that Japanese hybrid models occupy half of the world.
But this, Nissan’s route is not the same as the other two. Around 2000, Nissan Altra pure electric vehicle (Nissan Leaf predecessor) was launched, and then the Leaf was officially launched in 2009, and in 2010 Listed in North America. At present, Leaf has sold more than 500,000 vehicles worldwide. It is the first electric vehicle that has been accepted by the market and purchased in large quantities. It also lays a solid foundation for Nissan’s technology in the field of electric vehicles.
(Nissan Altra Pure Electric Vehicle)
But at the same time, Nissan is lagging behind in hybrids, but things turned around in 2016, and Nissan launched a new hybrid technology e-Power Previously used single-motor dual-clutch P2 type hybrid, Renault Nissan Alliance and Mercedes-Benz jointly developed).
e-Power uses a hybrid type consisting of an engine, two motors, and a battery. The engine supplies power from the generator. The motor is responsible for driving the wheels. When starting and driving at low speed, the battery is powered separately. At the same time, the engine dynamics supplies power according to the required power while charging the battery. When high power is required, the engine and the battery simultaneously supply power to the motor.
(E-Power System Principles)
(e-Power System)
The characteristic of this system is that e-Power always provides the experience of pure electric vehicles. The advantages of electric vehicles are all there, but there is no endurance anxiety.
I believe many people will ask questions. What is the difference between Toyota THS and Honda iMMD? Then let’s take a brief look at the characteristics of Toyota and Honda hybrid technology.
Toyota THS(Toyota Hybrid System) uses an engine, two motors, a battery, an e-CVT to mix, the engine and The motor can act on the tire at the same time. At low speed, the battery-powered power supply drives the tire. In general, the engine can directly supply power through the planetary gear set and charge the battery through the generator. At high speed, the engine and the motor simultaneously provide power.
(Toyota THS System Principles)
Talking about Toyota, you will say that “hybrid is only mixed with Toyota, and other hybrids” for two reasons. One is the planetary gear (e-CVT, gear-connected motor, sun gear connected to the generator, engine connected to the star carrier) application, able to calculate the power required in real time, the engine power is distributed to the transmission system and generator. The second is that Toyota technology has experienced more than 20 years of development, and all aspects have been relatively mature and perfect. However, the disadvantage is that the engine and the planetary gear are always coupled, so some energy is wasted under various working conditions.
Honda iMMD(Intelligent Multi-Mode Drive) is also an engine, two motors, one battery, e-CVT (unlike Toyota, but also to achieve power distribution) Composition, there seems to be no difference, but it is different from Toyota’s structure. The basic logic is the same. At low speed, the battery is powered by the battery to drive the motor. In general, the engine provides power supply and charging through the generator. The high-speed cruise state, the engine directly takes over the power output, and directly accesses the 5th and 6th gears. Gear ratio, driving the wheels.
(Honda iMMD system principle, battery-powered mode)
The technical advantage of Honda is that when the engine is used as the power supply, it can always maintain the best working condition to save fuel and provide electric energy. At high speed, the electric drive efficiency is gradually reduced, and the engine is directly responsible for the power through the mechanical structure. Output, to take advantage of the energy saving of the engine during high-speed cruise.
Compared with the two, THS has always existed due to mechanical coupling, and iMMD is no different from pure electric vehicles at low speeds. Therefore, Honda is better at this time, but at high speed, iMMD needs to convert the power source once. There was a slight “switching sensation”. The fuel consumption of both is almost the same.
In fact, the above two kinds of hybrids are similar to P2 hybrids, but in fact there are many different things, so they are unique. It is also because the actual effect is very outstanding, so it is highly sought after in the market.
In retrospect, Nissan e-Power replaces e-CVT’s power “smart distribution” with an electronic control system compared to Toyota. Compared to Honda, it simplifies its mechanical structure, reduces weight and improves overall power. System transmission efficiency. The e-Power only uses the motor as the power source. Under the driving conditions, it is exactly the same as the electric car, but it is precisely because of this that e-Power chooses a larger motor as the driving source to ensure stability. Power output, while also ensuring the efficiency of kinetic energy recovery.
(e-Power battery-powered condition)
(e-Power battery and engine are powered simultaneously)
(e-Power engine powers and charges the battery)
The e-Power engine is a HR12DE three-cylinder engine that has been matured. It reduces the number of structural parts and optimizes the intake and exhaust structure through the engine, achieving a very fuel-efficient state, coupled with a simple structure and high efficiency. The electric “drive” makes the whole system achieve a better fuel economy.
In addition, because the engine is always kept at a relatively high speed to ensure the most energy-saving conditions, the engine is noisy after starting, so Nissan applied two new technologies to solve this problem. The first is that when the sensor detects uneven road surface and the driving noise itself is large, the engine is started to generate electricity. Secondly, the road condition of the navigation route is judged in advance through big data collection, the energy consumption is calculated intelligently, and the engine is started in the noise-prone section in advance. Generate electricity to reduce the effects of engine noise.
The most important point is that the e-Power system uses a very small lithium battery pack. Currently, the NOTE model with e-Power technology, the lithium-ion battery pack is only 1.5kWh, and Serena is only slightly larger. . There are two reasons for this. On the one hand, the cost of the battery is very high. On the other hand, the size and weight of the battery pack will affect the layout of the car and the overall weight, which will affect the ride experience and fuel efficiency. e-Power dares to use such a small battery pack, thanks to Nissan’s confidence in its motor development and inverter efficiency, as well as the optimization of the entire electronic control system to ensure that even small batteries can meet the vehicle operating conditions. Demand.
Nissan introduced the NOTE-equipped e-Power in 2016 and entered the Japanese market. In the statistics released by Japan JADA in the first half of 2019, Nissan’s NOTE sales were only 1,000 fewer than the Toyota Prius’s 70,000 units. 66% of them are e-Power versions.
Nissan Layout
e-Power is not without its shortcomings. Since its power is completely provided by the motor, according to Japanese consumer feedback, there will also be “sufficient stamina” at high speeds.
For the Japanese road environment, most of the time the vehicle is blocked, the city section is blocked, and the e-Power can not only achieve 3.8 liters of oil per 100 kilometers (JC08), but also provide Ample speed-up performance and ride comfort. In contrast, iMMD has a fuel consumption of 4 liters of oil per 100 km (JC08) under the same working conditions, and THS is 4.3 liters of oil per 100 km (JC08). However, if you often drive on a high-speed section, although it is still more fuel-efficient than a fuel truck, its fuel consumption will increase significantly.
In fact, some people should have found that the structure of e-Power is similar to the ideal ONE extension program, but the difference is that Nissan can obtain the market: positioning.
In the extended structure of the ideal ONE, because the full function is realized, the front and rear two motors are arranged to realize the four-wheel drive, thereby adding complicated mechanical and electronic structures, although the performance is good, But it lost fuel economy. Nissan’s e-Power is different. Its positioning is urban traffic vehicles. It conforms to the usage scenarios of most people. On the basis of not worrying about supplemental energy and battery life, it provides the advantages of electric vehicles, with simple structure and pure purpose.
Nissan announced this year that it will introduce e-Power technology to China in the next two years. Then I have to face a very interesting problem. Nissan e-Power does not have a large battery pack, which means that the pure electric mileage is unlikely to meet the electric vehicle subsidy requirements. In addition, the current policy is Said that its license is still a blue card for fuel vehicles. Therefore, whether e-Power can succeed in China depends entirely on the competitiveness of its products. Without the influence of policies, the standards chosen by people will be absolutely absolute.
Of course, Nissan did not put “eggs in a basket”. At the Tokyo Motor Show, Nissan launched a pure electric crossover concept car Ariya for China, and a pure electric concept car for Japan. IMk. Nissan will gradually develop both hybrid and electric, and gradually advance from the fuel vehicle to the new energy vehicle era. While meeting energy conservation and emission reduction, it will give consumers the most practical and easy driving experience.