"There are only two hybrids in the world, one called Toyota and the other!" This sentence was broken with the launch of the Honda i-MMD in 2013, and under the Japanese fuel consumption test standard, the Hybrid Accord achieved a fuel consumption of 3.3L/100km, which is significantly lower than the Camry's 3.93L/100km. However, with the launch of the 2-speed EDU hybrid launched by SAIC in 2014, the title of "the world's strongest hybrid" was directly taken away by the Chinese brand, because the system surpassed the top hybrid benchmark model at that time, both in terms of design concept and fuel consumption, the Toyota Prius...
Roewe e550 with EDU transmission
But when SAIC Motor is full of expectations for the future of EDU hybrid, unexpected things happened, because the design of this hybrid system is too avant-garde, but SAIC's manufacturing process can not keep up, so when this hybrid system is officially mass-produced and listed, it will burst out of quality problems... At the same time, because the cost of this hybrid is too high, it is impossible to balance R&D and production expenses through the consumer market, so in the end, the ceiling of this hybrid technology - 2-stop EDU hybrid gradually withdrew from the market...
Gilly Thor Power
What is exciting is that Geely, which has always seemed to have no sense of existence in the field of hybridization, actually released a hybrid system similar to saic motor EDU at the end of 2021, a "Thor power" hybrid system based on the 3-speed DHT Pro transmission. And with the mass production of this hybrid system, domestic hybrid has officially entered an era of comprehensive confrontation with the Japanese system! Below, in order to facilitate everyone to understand this "domestic ceiling-level" hybrid system, while ensuring that some friends who do not know much about the type of hybrid and the working principle can keep up with the rhythm, so let's first introduce how Toyota and Honda's E-CVT gearboxes reduce fuel consumption, and what are the differences between the 1-gear E-CVT transmission and the 3-gear DHT Pro gearbox!
(ps: This article is slightly longer, it takes about 20 minutes to read, but if you can follow my train of thought sentence by sentence, I can guarantee that everyone can understand it, and after reading it, you will have a comprehensive understanding of the hybrid system!) I look forward to those students who want to improve their knowledge reserves, after reading it, they can leave your feelings in the comment area Oh ~)
Honda CR-V hybrid E-CVT transmission
Toyota and Honda hybrid models have transmissions called "E-CVTs", which has led many people to mistakenly think that their hybrid models are equipped with transmissions. But in fact, toyota and honda hybrid systems do not have a traditional gearbox, and the E-CVT has no gear, and it cannot rise or lower gear. So the question is, how can toyota and Honda's 1 fixed-gear E-CVT achieve far lower fuel consumption than those pure fuel vehicles with 6-8 forward gears cannot achieve? At this time, we have to mention the structural advantages of the hybrid system.
In-line mode
At present, the hybrid on the market can be roughly divided into three types: series, parallel and series parallel. Among them, the tandem hybrid is what we call "extender", as shown in the figure above, the tandem hybrid structure consists of an engine, a generator, a drive motor, plus a battery. When working, the generator generates electricity through the operation of the engine, and the driving motor then realizes pure electric driving through the electricity generated by the engine. So the question is, why does this scheme of converting mechanical energy into electrical energy and then driving the vehicle save fuel? After all, the transformation of energy will be accompanied by the loss rate! To figure this out, we only need to understand the characteristics of the engine!
Top: Syringe / Bottom: Engine suction resistance
Everyone should be able to understand that if an engine wants to save fuel, it must be efficient, and if it wants to be efficient, it must have little resistance. In fact, the engine is like a syringe, and the suction phase of the piston moving downwards is like we pulling the pusher of the syringe outward. The vehicle is in the idle and low-speed driving stage, because the driver only needs to step on a little bit of the accelerator pedal to achieve the speed demand, so at this time the engine's throttle will be in the small throttle opening corresponding to the small opening of the throttle.
It's like when we block the injection port of a syringe with our fingers and pull the pusher outward with only a tiny gap, the resistance is very large. Therefore, at this time, a large part of the work done by the engine to ignite gasoline will be wasted on the suction resistance, which will eventually cause the fuel consumption to soar when blocking the traffic. It can be seen that if we want to make the engine fuel efficient, we need to keep the engine output power that determines the throttle opening in the maximum efficiency working range!
Nissan e-POWER series hybrid system
However, for the current congested road conditions, it is impossible for the engine to be constant in the most efficient working area. So the engineers designed a hybrid system in series, so that the engine, whether it is stuck in traffic or not, can always maintain a large throttle opening to drive the generator, and then leave the work of driving the wheels to the drive motor. Under this operating logic, the engine is no longer bound by driving speed and road conditions. These are the reasons why the tandem hybrid mode, which focuses on generating electricity from the engine, can make ultra-low fuel consumption in congested road conditions.
轩逸e-POWER
At present, the more representative models of tandem hybrid are the ideal ONE and nissan Xuanyi's e-POWER. Among them, the ideal ONE is equipped with a large-capacity battery and can also be charged externally, so the engine will not start to generate electricity under the premise of sufficient power. The Nissan Xuanyi e-POWER has a small battery capacity, so the engine will often start to generate electricity at low speeds, and after reaching the medium and high speed, the engine will continue to generate electricity. However, because the engine is in the most efficient range during the entire working time of tandem hybridization, the fuel consumption of Xuanyi e-POWER's NEDC per 100 km has made a staggering 3.9L, which is 25% lower than the fuel-only version of Xuanyi's 4.9L/100km NEDC fuel consumption!
But that doesn't mean that tandem hybridization is perfect, because it's born with these two unsolvable problems. The first problem is the cost, because the series hybrid power generation process and the drive process are carried out at the same time, so it needs to have a generator and a drive motor at the same time, which will lead to its cost is higher than the use of only one motor, each time the motor is only in the power generation, drive conditions of the two to choose one of the parallel hybrid higher.
Series hybridization
The second problem of tandem hybridization is energy loss, and the problem that the drive motor is not as efficient as the engine in the medium and high speed range. Among them, in terms of energy loss, because the tandem hybrid first needs to convert the mechanical energy of the engine into electrical energy through the generator, and then the drive motor converts the electrical energy into the mechanical energy of the driving wheel, so this time it will lose about 30% of the energy conversion loss.
When the vehicle is in the low-speed range, due to the low efficiency of the engine, and also to experience the stop-and-go idle time, even if the 30% energy conversion loss is deducted, the efficiency of the tandem hybrid can also complete the explosion of pure fuel vehicles. However, if the speed is increased to 60-80km/h and above, the pure fuel vehicle that enters the high-efficiency and fuel-saving working conditions through a larger throttle opening will explode and need to consume an additional 30% gasoline to make up for the 30% energy loss of the tandem hybrid. Therefore, in Europe, where the roads are relatively smooth and the average speed is high, the local car manufacturers have basically chosen the parallel hybrid route to be discussed below.
Parallel hybridization
Functionally, parallel hybrids allow the engine to drive the wheels alone, the motor to drive the wheels alone, and even the engine to drive the wheels together with the motor. Therefore, compared with the tandem hybrid that can only drive the wheels with an electric motor, the acceleration performance of the parallel hybrid system will be better.
Among them, BYD is the parallel power advantage to the extreme of the manufacturer, such as qin pro plug-in hybrid through the equipped with a high-power drive motor, the use of the drive motor and the engine together to drive, torque superposition advantages, easily 0-100km / h acceleration time shortened to 5.9 seconds. You know, the 100-kilometer acceleration time of the QinPro pure fuel version equipped with the same 1.5T engine is 9.16 seconds, which is equivalent to a high-power motor making the 100-kilometer acceleration time of the QinPro plug-in hybrid more than 3 seconds faster! This shows how much advantage parallel hybrid has in terms of power.
BMW 5 Series 530Le drive mode
In addition to accelerating faster than tandem and pure fuel vehicles, because it can switch to the mode of engine driving alone when driving at high speed, and the engine will reach a high-efficiency working range at this time, the high-speed fuel consumption of the parallel hybrid system will be comparable to that of fuel vehicles, which is far more fuel efficient than tandem fuel savings. This is also the reason why the European hybrid models of BMW X1 New Energy, Mercedes-Benz E-Class New Energy, and Audi A6L New Energy have adopted parallel hybrid models in Europe, as mentioned above, in Europe, where parallel hybrids are used.
In summary, parallel hybrid has the advantages of fast acceleration and high-speed fuel saving, but because it has only one motor, it does not have one for power generation in traffic jams like tandem hybrid, and one for driving a total of two motors, so parallel hybrid in the urban area to save fuel depends on the battery power. If the power is enough, then the engine can be completely turned off in congested road conditions to drive with the motor; but if the battery is insufficient, the vehicle can only be driven by the engine alone, and the fuel consumption when the traffic jam is bound to be much higher than that of the tandem type. It is not difficult to see from the comparison of the two structures of series and parallel, their respective advantages and disadvantages are obvious, so in order to achieve low-speed urban driving and high-speed driving are fuel-efficient, it is necessary to combine the two, and their combination is called "series parallel connection".
Honda i-MMD two modes switch
Since the series parallel hybrid can be switched to series mode in congested road conditions, the power generation motor is driven by the engine, and the drive motor is powered to drive the wheels, so the series parallel system also needs to be equipped with two motors to complete the work. When the vehicle is driving to high-speed road conditions, the series parallel system can switch to parallel mode, that is, drive the wheels directly through the engine. Looking at Toyota's THS and Honda i-MMD hybrid, although the two work differently, in fact, both are series parallel hybrids. The pioneer of the domestic string parallel hybrid system is the SAIC EDU we mentioned at the beginning, and then BYD and great wall have also joined the hybrid route of string parallel.
So why would I say that Geely's "Thor Power" hybrid system is a "domestic hybrid ceiling"? Is it just because Geely's 3-speed DHT Pro transmission has one more gear than the Great Wall DHT's two-speed transmission? Non also! This is because Geely's "Thor Power" hybrid system uses a completely different hybrid structure from other domestic brands, a structure that Toyota is only willing to use on million-class Lexus luxury cars!
Great Wall DHT hybrid system structure diagram
From the above figure, we can see that the two gears of the Great Wall DHT hybrid system can only be used by the engine (ICE) and the generator (GM), while the drive motor (TM) directly bypasses the 2-speed gearbox and the wheel connection, that is, the drive motor in the Great Wall DHT hybrid cannot enjoy the benefits of two gears.
Geely Raytheon power hybrid system
The difference between Geely's "Thor Power" hybrid system is that, as shown in the figure above, its engine, generator and drive motor can all use 3 gears. Because compared with other hybrid systems, Geely hybrid drive motor has more ability to use a 3-speed gearbox, so in this set of hybrid pure electric driving conditions, the drive motor responsible for driving the vehicle can select the gear according to the speed, so as to achieve the purpose of reducing the power consumption of the drive motor. Not only that, during the deceleration process of the vehicle, the drive motor can also use the lowest gear of the three gears to meet the current speed to amplify the motor torque, so as to achieve stronger kinetic energy recovery efficiency.
Geely 3-speed DHT Pro transmission
If you look at it from another angle, due to the existence of three gears, under the premise of reaching the same target value of torque, Geely's hybrid system can use a motor with less power and a smaller volume, and then achieve it through the amplification of the gear, which is equivalent to reducing the size of the motor. This is the difference between Geely multi-gear hybrid and other brands of multi-gear hybrid.
In fact, the operation of adding gear to the hybrid motor was used by the Toyota Group as the grandfather of hybrid motor as early as 2006 on the high-end brand model Lexus GS450h. But unlike Geely, the 2-gear transmission on the GS450h at that time was dedicated to the drive motor, and the engine could not be shared. The working logic of this 2-speed gearbox is very simple, when the vehicle is in the stage of static start acceleration or low-speed driving, the vehicle's drive motor is hung on 1st gear to amplify the torque to improve the acceleration performance; and when the vehicle is driving at high speed, the drive motor will be hung up on the 2nd gear, which improves efficiency by reducing the speed, and can also increase the maximum driving speed of the vehicle.
It is precisely because the drive motor of the GS450h is equipped with a 2-speed gearbox, so the 0-100km/h acceleration time of this car is 1.3 seconds faster than the GS300, reaching 5.9 seconds, and the NEDC fuel consumption is also controlled at the level of 8.1L/100km. However, the price of this car has also risen from 696,000 for the GS300 to 898,000!
In 2017, Lexus launched the LC500h sports car, which added 4 gears to the original THS-II, and these 4 gears can also be used by the drive motor and the engine. Under the torque amplification of this 4AT, although the LC500h's 3.5L self-priming engine and motor power are not large, it still makes an excellent acceleration performance of breaking 100 in 5 seconds. It is a full 0.9 seconds faster than the GS450h, which has similar engine and motor dynamic parameters, and this is achieved under the premise that the LC500h car weighs more than 100 kilograms more than the GS450h.
In addition to the LC500h, Lexus flagship sedan LS500h also uses this hybrid system, as a D-class luxury sedan, LS500h's NEDC 100 km fuel consumption is only 6.8L, and the 100 km/h acceleration takes only 5.4 seconds. This shows how beneficial it is to add a multi-gear transmission to a hybrid system, including drive motors.
Toyota multi-stage hybrid system structure
With so much padding on it, you can finally get into today's topic! If matching a gearbox to a hybrid system, including a drive motor, is a matter of benefit, why hasn't any hybrid system in a family car equipped with this technology so far? In addition to technical difficulties and high costs, there is a very important reason that ordinary family cars are mostly transverse engines, and there is basically no space to insert a gearbox that can provide a gearbox for the drive motor in the cabin under the condition of arranging a hybrid motor.
Left: SAIC EDU / Right: Geely DHT Pro
At this time, looking at the solutions on the market, only the compact and lightweight form of the planetary gearset can achieve up to 3 gears in the limited lateral space of the transverse engine compartment, and it will not cause power interruptions when shifting gears like SAIC EDU's AMT gearbox in the past.
3-speed DHT Pro transmission
However, due to the extreme difficulty of the processing process of the planetary gear set, only global manufacturers such as ZF, Aisin, and General Motors and Ford have the strength and money to build, so saic motor EDU, which was the earliest in China to create a gear shifting gearbox for the drive motor and engine, only adopts a simple structure AMT structure. It can be seen that in order to produce this set of 3AT through the planetary gear set, Geely must have spent a lot of money behind it and suffered a lot.
From the above figure, we can see that Geely's 3-gear DHT Pro gearbox is located between the drive motor and the engine + ISG motor, so whether it is the drive motor driving the wheels alone, the engine driving the wheels alone, or the two driving the wheels together, it is possible to change the speed ratio with the help of this 3AT gearbox. However, the point to be stated in advance is that geely officials did not give the specific working logic of the engine + ISG motor, drive motor and 3-speed transmission in this hybrid system under different working conditions.
But according to the general logic of the hybrid system, we can also estimate the approximate: when the vehicle is in the low-speed or low-speed range, the clutch named "first clutch" on the right side of the above figure will be disconnected, which in turn will disconnect the engine + ISG motor from the 3AT gearbox, and the vehicle will be driven by the drive motor combination 3AT gearbox. At this time, the engine will decide whether to turn off the engine or start the ISG motor to generate electricity according to the battery level. And this state is like Honda's i-MMD, in series mode at medium and low speeds. However, it should be noted that Honda's i-MMD can not have a gear, and it cannot be like Geely's "Thor Power", which can make the motor in a power-saving state through 3 gears.
Once the first clutch is combined, the power of the engine will be transmitted to the wheel through the 3AT gearbox, and if the drive motor continues to run at this time, then the power of the engine and the motor will be transmitted to the wheel together. If the drive motor stops working, it becomes a direct engine drive, which is in parallel mode.
Hoshigoku L Thunder Divine Intelligence Hi · X oil-electric hybrid version
Since the model of this test drive is the Hoshigoku L Raytheon hybrid version of the trial car, the appearance and interior are not the final version, so let's mainly talk about the real performance of this car in terms of fuel consumption, power and NVH. In terms of power, the Hoshigoshi L Hybrid Edition is equipped with a new three-cylinder 1.5T engine, with a maximum thermal efficiency of 43.3%, but due to the use of fuel-efficient Miller cycle, the power performance has decreased compared to the Otto cycle, the maximum power is 150 horsepower, the peak torque is 225N·m, and the engine matches the 3-speed DHT Pro transmission that we highlighted above.
Like rav4 and CR-V hybrids, the Hoshikoshi L hybrid has no external charging port, so fuel consumption is almost unaffected by battery capacity and power. Let's first talk about the fuel consumption performance of this car, our one-way test drive distance is 50.4 kilometers, covering the city ring road, the city trunk road, the national highway, the mountain road, the whole journey takes 1 hour and 15 minutes, the average speed is 40km/h, and finally in the car 3 adults, and without turning on the air conditioning, the apparent fuel consumption I drove was 4.1L/100km. Considering that the curb weight of Hoshigoshi L is heavier than that of RAV4 and CR-V, if its apparent fuel consumption is similar to the actual fuel consumption, then this performance is quite excellent.
In terms of operating logic, as I said above, the official did not give the specific working logic of the engine + ISG motor, the drive motor and the 3-speed transmission under different operating conditions. But based on my fumbling in the test drive, I found that it was the same as the Toyota and Honda hybrids, and the engine did not start at a low speed start. At this point, the battery will power the drive motor to drive the vehicle in pure electric mode. As the speed of the vehicle increases, the engine starts and generates electricity separately with an ISG motor and is not connected to a 3AT gearbox. This means that if you drive a hybrid star over the city, then the car is completely a tram feeling.
When the speed of the hybrid Star-Etsu L exceeds 80km/h, or when the vehicle is driving on a section with a large load in the uphill road, the hybrid system will automatically switch to parallel mode, and the engine will be connected to the 3AT transmission and directly output power to drive the wheels. In addition, if the driver accelerates sharply at the starting or low-speed stages, the engine will also be paralleled with the drive motor, bringing the most powerful power output to the vehicle through the 3AT transmission, which is also a situation that the Honda i-MMD without a gearbox cannot achieve.
Since the hybrid system of RAV4 and CR-V has only 1 fixed gear, no matter how the driving speed and throttle opening change, there will be no setback, but the Hoshigoe L oil-electric hybrid version has 3 gears, and the power output of the motor and engine will pass through 3AT and then pass to the wheel, so this will test its shift smoothness. In this test drive, I also focused on this point of experience, after trying a variety of driving styles and methods, I found that this 3AT whether it is slow acceleration, sharp acceleration, deceleration, taxiing will not appear to have setbacks, and the engine and motor intervention is fast and smooth, it can be said that this hybrid system is quite perfect.
The noise of the hybrid system is a dimension that people often overlook, of which the source of noise usually has two parts, one is to create a more thermally efficient engine, manufacturers will try to advance the ignition angle of the engine as much as possible, which will lead to the combustion noise of the engine become larger; the second is to drive the motor to a high speed, and it is easy to make the electric drive gearbox gear produce a high-frequency whistle. These problems have appeared in the hybrids of Toyota and Honda.
In the process of test driving the Hoshigoku L Hybrid Version, I mostly drove with the window open, and it is reasonable to say that the sound of the engine and motor should be clearly heard in the car, but when I drive in the city in a relatively gentle style, I am basically unaware of the movement of the engine when it intervenes, as well as the sound and vibration of the operation. So I think that if you don't inform the test driver in advance that this is a hybrid model, I believe that many people will mistakenly think that this is a pure electric vehicle for the first time to open the Star Yue L oil-electric hybrid version! However, this car is quiet as a pure electric vehicle-like hybrid, the noisiest working conditions are not floor oil acceleration, but the sound of the engine temporarily starting to generate electricity when idling, the poor hearing of the three-cylinder engine itself, the superimposed engine power generation required for some speed, the final sound is far more obvious and rougher than the general pure fuel vehicle. Fortunately, hybrids rarely generate electricity when idle.
In just a few years, Chinese car brands have not only evolved from no decent hybrids to excellent hybrids blooming everywhere, but also directly spelled to the level of "inner volume"... The BYD DM-i hybrid that can break the wrist with Honda has only 1 gear, but it has achieved the ultimate cost performance, selling at least 105,800. The Great Wall DHT arrived one step late, but it "rolled" the hybrid to 2nd gear. Although Geely did not release the hybrid for a long time in the face of "infamy", this release made a big move, got the extremely difficult process, and directly "rolled" to the international leading level! This is definitely a good thing for us as consumers, to know that the price of the Lexus GS450h with 2 gears in 2016 is as high as 745,000, while the pre-price of the Xingyue L oil-electric hybrid version with 3 gears today is only 173,700 yuan, which once again confirms the truth: if a technology is mastered by China, it will soon become a cabbage price!