At the beginning of 2021, BYD officially launched its super hybrid system - DM-i, stemming from the success of DM-i, quickly pushed the domestic PHEV hybrid structure to a climax, so that the BYD brand, completely rooted in the field of new energy; in April 2022, BYD officially announced that it would stop the production of fuel vehicles, so far, the BYD brand is a new energy brand focusing on the new energy field.
In the second half of 2021, after the BYD DM-i system has attracted the attention and recognition of consumers, many domestic brands will also carry out a scramble for hybrid technology wars, among them, the Great Wall DHT and Geely Raytheon and other structures, much attention from users, in the DM-i system and DHT multi-stop structure system, consumers are more and more vague, each one is boasting of its own hybrid structure, but for users how to choose, a variety of hybrid systems, what are the characteristics?
Commonalities between hybrid systems
Since Honda launched its iMMD hybrid system, the hybrid system from Toyota to open the transformation, in the iMMD structure, Honda has created a research and development ideas innovation, between the motor and the engine, a lot of associations, in the internal structure, the reference to the series and parallel dual structure, according to the motor and engine work efficiency and their respective characteristics, in different road conditions, by different power output sources to do work, so as to maximize the power and efficiency as much as possible.
As we all know, the initial torque of the motor is very large, the torque of the engine is a linear growth, which is why the fuel vehicle needs a gearbox to match the gear, that is, in the initial stage, the use of the gearbox gear ratio conversion, amplification of torque, in order to let the fuel car have better starting characteristics; the motor can reach the maximum torque at the beginning, in the initial stage, the use of the motor can ensure maximum efficiency, in the high-speed stage, the engine can better drive the wheels at low speed, which is why the fuel car urban fee, The principle of high-speed fuel saving; through the hybrid structure, the hybrid model can not only ensure energy saving and economy, but also take into account the very good power.
After the Honda system was recognized and successful, more brands will take the Honda hybrid system as the basis and begin to look for the advantages and disadvantages of the iMMD system for development; Honda in the iMMD system, using e-cvt structure, although the engine can enter the direct drive mode, but there is only one gear, so when driving, there will be restrictions on the conditions of direct drive, when the speed is lower than 60k/h, the engine can not have a good gear ratio, so it can not be direct drive, and honda iMMD system, The battery level is also relatively small, so in the battery loss state, the Honda iMMD system will have the possibility of weakening power.
On the basis of Honda's iMMD system, various domestic companies have opened the "eight immortals across the sea, each showing its magic".
Differences between hybrid systems
As mentioned above, Honda iMMD system has created a precedent for the new hybrid system structure, the current domestic hybrid system, are using such a structure, in the structure, are supported in series and parallel mode, in the series state, the engine drives the generator to generate electricity, the kinetic energy into electrical energy, the output of electrical energy charged into the battery and output to the motor; in parallel mode, the engine and generator can do work at the same time, jointly drive the wheel; this is the common point of many current hybrid systems.
As mentioned earlier, because honda iMMD hybrid system, there is only one gear gear gear ratio, limiting the engine into the direct drive state, must reach a certain speed, can enter the direct drive mode, so in the state of power loss, there is no way to ensure the maximum power, and domestic companies are optimized according to their own capabilities.
At present, the domestic hybrid system is divided into two factions, one is the BYD DM-i system, which continues to use the e-CVT structure to strengthen the electrical energy, and the other is to match the multi-gear transmission for the engine, that is, the hybrid special DHT, in order to provide greater convenience to the engine.
There are definitely users here who are struggling with their purchases, which is better? Which is more reassuring? Let's dissect it step by step.
At present, whether it is the Great Wall, Geely or Chery, they all use a multi-gear DHT structure, and in multiple gears, and BYD's 1-stop e-CVT has a very large deviation in logic, and can even be said to have taken a completely different route. In a hybrid system, the motor and the engine are all powered together, and the importance of the engine and the motor, that is, which is dominant, depends on the engineer's strategy in the development.
Under the multi-gear DHT structure, the Great Wall currently uses 2 gears on the Mocha DHT PHEV model, Geely uses 3 gears in the Thor system, the more gears, the more time the engine will have to participate in the driving wheel work mode, because the more gears, can give the engine torque amplification more, suitable for more working conditions, especially in the battery loss state, the engine can enter the parallel direct drive mode at a lower speed, even in the state of power loss, it can also avoid power weakening as much as possible The more gear DHT can achieve more complex power matching, but in the system internal control logic is more complex, there is a higher test of reliability; previously, many people felt that the range extender is "take off the pants" fart, compared to the complex PHEV hybrid structure, the extender is simpler, in the reliability, in theory, it will be higher, so the extender electric vehicle is gradually more and more recognized by consumers.
In the multi-gear DHT hybrid structure, the more gears, the importance of the engine gradually increases, and it can face more complex power matching, but the reliability will also be reduced, which is inevitable. The advantage of DHT is that it can cope with more complex power conditions, and the disadvantage is that it tests the reliability of the system.
BYD still continues the strategy of Honda iMMD, using e-CVT structure, only 1 gear, as mentioned above, if there is only 1 gear, the demand for the power system is greater; but as soon as it hears the need for a more powerful power system, BYD instantly "spirit", electrification is BYD's housekeeping skills, but also the first domestic enterprise to open electrification research and development.
BYD knows that if it continues to use e-CVT, it will have a higher demand for the power system, so in other brands of DHT hybrid structure in China, the motor generally uses a motor of about 300-400V, while BYD directly uses a 750V motor, so that the sense of engine participation can be reduced to a greater extent, which is also BYD said at the time of the release of the DM-i system: This is a set of electric-based hybrid structure, but 750V has entered the high-voltage system. More need power module can have enough bearing capacity, in the past, BYD has developed Sic silicon carbide power module, in the BYD Han high power version of the use, compared to the previous IGBT module, more able to cope with high voltage capabilities, and BYD's own IGBT module, but also has the industry's forefront of reliable capabilities, this is BYD's own advantages in the field of batteries, electric drives, electronic control; so, BYD's strategy is to increase its own electric drive system capabilities.
As mentioned earlier, Honda iMMD system is very afraid of power loss, BYD increases the battery power of the hybrid system, using a blade battery dedicated to the hybrid system, because it increases the battery power, but also increases the pure electric endurance, so the DM-i system is directly promoted to plug-in hybrid, because the hybrid system, the engine also uses a more efficient engine, in order to be able to in more cases, in the tandem structure, to ensure better power generation capacity, but also to reduce energy consumption as much as possible.
DM-i system, because of the higher power of the motor blessing, even if there is only a single gear, can also provide a very good power response, increase the battery power, provide longer power protection, the engine is also as far as possible to protect the electric drive, longer in the series structure, because the structure is simple, the theoretical reliability is also higher, the research and development cost is also lower, can quickly adapt to different models, which is also the main reason why the DM-i system can grow rapidly.
Write at the end
From the current point of view, in the two system structures, there are advantages and disadvantages, but in the market performance, because the DM-i system structure is simple, so it can better reduce the price, get more consumer recognition and acceptance; and the DHT system, is also a newly developed new idea, if the DHT structure is continuously optimized in the future, the cost can be infinitely close to the e-CVT structure, at that time, in order to better compare.
At present, the development of domestic hybrid systems is showing explosive growth, in the market, BYD has a first-mover advantage and the previous technology accumulation, so it is also too early to seize the market advantage, but with the enrichment and accumulation of hybrid technology, the technology has become more outstanding and mature, so the future market, not only the test is the hybrid system, in the context of all systems are mature and reliable, model design and product capabilities are also more important, the future, the war of the hybrid system, the need for more dimensions of the consumer perspective to think, In order to truly seize the leading power of the future new energy market.