[EV Vision Technology Comparison] Nowadays, when vehicle electrification has become the mainstream of development, diesel locomotives seem to gradually withdraw from the rhythm of the historical stage. However, the reality proves that the models with internal combustion engines will not disappear for a long time to come, but will have certain advantages in some aspects. However, this species that does not suffer from "mileage anxiety" will make car owners suffer from another disease-"fuel consumption anxiety". Therefore, on the issue of how to treat it, plug-in hybrid models have become this good medicine.
Before, we made a comparison between BYD DM-i and Great Wall Lemon DHT (extended reading: BYD DM-i or Great Wall Lemon DHT, who represents the peak of domestic hybrid technology? ), which proves that domestic hybrid technology is gradually rising and has the strength to compete with foreign hybrid technology. Of course, this technical field in China is more than these two. Looking at the industry, basically most OEMs have started to develop their own latest hybrid technology, and among them, Chery’s Kunpeng DHT has become another new hot spot after the first two. If you look closely, you may find that compared with the hybrid technology of the Great Wall, the word DHT appears behind Chery’s technology. What is the difference between it and lemon DHT?
What does DHT mean?
If you answer what is the most obvious difference between Kun Peng DHT and lemon DHT, there is actually a difference in word meaning.
The DHT of great wall lemon is calledDedicated Hybrid Technology, the Chinese translation isSpecial technology for hybrid power, is a complete hybrid technical scheme, including engine, transmission, drive axle, battery and other components.
DHT of Great Wall Lemon
Chery Kunpeng’s DHT is calledDedicated Hybrid Transmission, that isSpecial gearbox for hybrid powerBased on the traditional fuel vehicle gearbox, some electrified components are added to realize hybrid power technology.
DHT of Chery Kunpeng
So it can be seen that there are some differences in the technical route between the two. Please look down.
Comparison of hybrid architectures
Dual-motor+engine combination may be the trend of hybrid technology development now. Take DHT of Great Wall Lemon as an example, it is a powerful three-engine/four-engine power system composed of a 1.5L/1.5T hybrid special engine, a highly integrated dual-motor hybrid gearbox and a 135kW three-in-one two-gear electric drive rear axle. Under this system, three different specifications of power (PHEV/HEV) assemblies suitable for Class A, Class B and Class C have been successively introduced. In addition, under the PHEV architecture, there is also a "1.5T +DHT130+P4" four-wheel drive powertrain, which corresponds to different levels of products to meet the diversified choices of users.
Specifically, the lemon hybrid DHT consists of a high-efficiency hybrid special engine, a highly integrated dual-motor hybrid gearbox and a 135kW three-in-one two-speed electric drive rear axle, forming a powerful three-engine/four-engine power system, which brings super power. The maximum power of HEV two-drive system is 180kW, and the total power of PHEV two-drive system can reach 240kW. The front and rear axle motors with PHEV+P4 structure can output power at the same time, and the maximum system total power can reach 320kW. The intelligent four-wheel drive system of this architecture has strong climbing ability, such as achieving 60%-65% maximum climbing degree when dry asphalt pavement and 15%-18% maximum climbing degree when snow.
High fuel efficiency hybrid special engine
In terms of transmission, Great Wall Lemon DHT is similar to Honda i-MMD, except that it has two gears when the engine is driven, while the latter has only one gear when the engine is driven. By selecting the gear, it can give full play to the performance advantages of the engine. The system also adopts dual-motor series-parallel topology, which can realize EV, series connection, parallel connection, energy recovery and other working modes, and achieve a perfect balance between power and fuel consumption in various driving scenarios. As for the battery, the Great Wall Lemon DHT architecture is equipped with the world’s largest capacity and high-efficiency hybrid battery, which has the highest performance in the industry with a pure battery life of 200km. With CTP(Cell to Pack) technology, the energy density of the battery pack reaches 160Wh/kg, and it supports 11kW AC slow charging and DC fast charging.
High integration hybrid DHT transmission
Although there is not much information about Chery Kunpeng DHT, we can still see the clue from the known information.
From this exploded view, we can roughly see the structure of the whole system. Chery Kunpeng DHT also uses the combination of engine and dual motors, but here I want to knock on a blackboard to draw a key point. Different from the mainstream development, Kunpeng DHT is the only hybrid architecture driven by dual motors in China brand at present. An output mode mainly driven by electricity can be provided. In this hybrid system, the motor bears the main driving responsibility, and the engine can supply energy for the power battery under low load conditions. Therefore, two relatively low-power drive motors are equipped with FIO fixed-point injection oil-cooled motor technology and TEM dual-motor power distribution technology developed by Chery, in order to replace the effect of a single high-power drive motor.
In terms of data, the maximum power output torque of Kunpeng DHT can reach 510N·m, and the whole box torque density is 35 N m/kg, which can match large and medium-sized cars and SUV models, and can realize nine high-efficiency working modes such as single/double motor drive, extended range, parallel connection, direct engine drive, single/double motor braking energy recovery and driving/parking charging. Kun Peng DHT adopts TEM ultra-efficient dual-motor power distribution technology, which can choose the best electric drive source and gear according to the load size to improve the driving efficiency, thus creating a smooth driving experience and more efficient power distribution. The maximum transmission efficiency is more than 97.6%, the average efficiency of electric drive in NEDC working condition is more than 90%, the peak efficiency of flat wire motor is more than 97%, the power is 6.0kW/kg, and the fuel saving rate in low power mode is more than 50%.
In addition, Kunpeng DHT has 11 combined gears (seemingly the largest in the world? ）。 However, it should be noted here that the gear position of Kunpeng DHT is not limited to these 11 combinations. Due to the existence of dual motors and the provision of a 3-speed transmission device in the engine direct drive mode. You know, most of the mainstream technologies now adopt a direct clutch structure, that is, the generator can directly drive the wheels. However, when they are all direct-drive output, they all have only one gear, which limits the highest efficiency working range (the difference between ordinary bicycles and variable-speed bicycles), so Kunpeng DHT is equipped with three gears on the engine to broaden the engine driving performance. First of all, the first speed ratio is relatively large, which is mainly used for starting and accelerating. The third speed ratio is very small, mainly to ensure low engine speed, low fuel consumption and noise reduction when driving at high speed. Among them, the second speed ratio mainly takes into account the shift of the first gear and the third gear to ensure the smoothness of the shift, and at the same time takes into account the fuel consumption at the middle and low speeds.
It is worth mentioning that these permutations and combinations can achieve dozens of gear combinations, but the manufacturer has chosen 11 most suitable gears. In different working scenarios, the built-in control system of Kunpeng DHT calculates the optimal working gear in real time, and cooperates with Chery’s FIO fixed-point injection oil-cooled motor technology, TEM ultra-efficient dual-motor power distribution technology and ultra-smooth TSD dual-shaft drive design to achieve the balance of power, ride comfort and economy.
Comparison of working principles
There are four working modes of Great Wall Lemon DHT, including pure electric drive mode, series mode, first gear direct drive mode (low speed cruise), first gear direct drive mode (performance direct drive), second gear direct drive mode (high speed cruise) and energy recovery mode.
The important core of overall fuel saving is to make the engine work in an efficient working point area. When driving at low speed in general urban areas, lemon DHT will switch between EV mode and series mode, and maintain the engine in the most efficient area. When driving in suburbs and viaducts, the series mode will still be adopted at medium and low speed, but at medium and high speed, the engine will start to intervene, and when encountering heavy load demand, the engine+parallel drive mode will be adopted, which not only maintains high efficiency, but also provides sufficient response for power. Finally, at high speed, the engine direct-drive working point will directly fall in the high-efficiency area, or when the power is enough, EV battery life will be adopted to reduce fuel consumption.
As can be seen from the published data, the working mode of Chery Kunpeng DHT can be said to be another way.
First of all, the front part will be equipped with a small displacement (1.5T) inverted engine. Why did you choose this engine type? First of all, the intake manifold of the inverted engine is shorter, and the air intake is more direct and smooth. In addition, the air does not need to be heated above the engine to reduce the air density and oxygen content, so the engine burns more fully, the thermal efficiency is higher than that of the upright engine, and the fuel consumption is correspondingly reduced. In addition, this engine has a relatively compact volume to reduce the cabin space and lay the foundation for weight reduction because the intake manifold and exhaust manifold do not need to be wound up and down from the engine for half a turn.
The dual-motor part of the predecessor is composed of two low-power driving motors. Why choose two low-power drive motors but not one high-power motor directly? The reason for this is that if a high-power motor is used, the efficiency of the motor will be greatly reduced at first when it starts at low speed and runs at high speed, and when it enters the power loss state, the engine will start to intervene in power generation, and the fuel consumption will inevitably increase. Therefore, using two low-power motors can make the whole hybrid system work in a high-efficiency area with the same comprehensive performance. After that, it is combined with the previously mentioned Kunpeng DHT gearbox to achieve the purpose of fuel saving. In addition, after adopting the dual-motor scheme in manufacturing cost, the dependence on high-precision gears is relatively reduced. After all, this aspect can only rely on imports for the time being.
Who are the models under DHT technology?
WEY macchiato
On April 15th this year, Great Wall Motor conducted an online lemon hybrid DHT vehicle test, which was the first time to be tested with a real vehicle. The tested model was WEY Macchiato, which will be listed soon. This model is equipped with the latest lemon hybrid DHT technology of the Great Wall, and is also equipped with the combined configuration of 1.5L Atkinson cycle engine and motor. The maximum horsepower of the engine is 102kW, the maximum power of the motor is 154kW, and the combined maximum power is 190kW. It is worth mentioning that the fuel consumption per 100 kilometers is only 4.7L and the maximum cruising range can reach 1100km. The subsequent PHEV plug-in hybrid vehicle has a pure electric cruising range of 110km.
Tiggo 8 PLUS PHEV
Tiggo 8 PLUS PHEV is Chery’s first model equipped with DHT hybrid system, which adopts a three-motor four-wheel drive hybrid system with 1.5T turbocharged engine+front double motor+rear single motor. Among them, the maximum power of the engine is 125kW, the peak torque is 252N·m, the official 0-100km/h acceleration is only 4.9 seconds, and the comprehensive fuel consumption is only 1.3L/100km.
EV vision view:Although the published information is very limited, through the comparison of these two technologies, we can see that their innovation in hybrid technology is enough to compete with hybrid power enterprises, which not only opens the door to the development of domestic hybrid technology, but also makes China brand occupy a place in the world. At present, the latest "Roadmap 2.0 for Energy-saving and New Energy Vehicles" issued by China Automotive Engineering Society clearly puts forward that traditional vehicles should be fully "mixed" in the next 15 years. By 2035, among the non-new energy vehicles that still occupy half of the market, hybrid power will become the leading force. Therefore, the automobile industry has developed in parallel with many technical routes. In order to realize the low-carbon of energy-saving vehicles, the automobile factory must establish a new hybrid technical route. Therefore, both Kunpeng DHT and Lemon DHT will become the new trump cards representing the development of hybrid technology in China. In the future, EV Vision will dynamically evaluate two vehicles based on its own hybrid technology, so stay tuned!
