From the establishment of the research and development of a new hybrid platform in 2018 to the release of the "Great Wall Lemon Hybrid DHT System" in December 2020, Great Wall Motors' layout in new energy vehicles has gradually become clear, which also indicates that 2021 is destined to be an extraordinary year
The first production model, the WEY Macchiato DHT
In March 2021, we were first exposed to "WEY Macchiato DHT" equipped with the "Great Wall Lemon Hybrid DHT System", and then at the Guangzhou Motor Show, Great Wall Motors unveiled the "WEY Macchiato DHT-PHEV" and "WEY Latte DHT". At the end of the year, the models of its "Haval" brand also began to be equipped with this hybrid system.
WEY latte DHT is also coming, and the coffee series will be fully transformed
Obviously, the "Great Wall Lemon Hybrid DHT System" has become an important strategic technical reserve for the comprehensive transformation of Great Wall Motors in the next few years, and today we will take a good look at this hybrid system and talk about its technical characteristics.
What is the "Great Wall Lemon Hybrid DHT System"?
In a nutshell, the "Great Wall Lemon Hybrid DHT System" is:
The three components of the Great Wall Lemon Hybrid DHT system
1. A set of highly integrated oil-electric hybrid system;
2. Support two dynamic architectures;
3. Three powertrain combinations for different models.
Let's split it down bit by bit.
A highly integrated oil-electric hybrid system
Since it is a hybrid system, it must include "hybrid special engine", "hybrid special transmission" (hereinafter referred to as "DHT"), "motor" and "electronic control".
Great Wall lemon hybrid DHT system display
The Great Wall Lemon Hybrid DHT System consists mainly of a 1.5L/1.5T Hybrid Engine, a Hybrid Transmission (fixed shaft), a Motor (Generator + Drive Motor), a Motor Controller and an integrated DCDC System.
"Engine": 2 types of hybrid engines
Pictured: Great Wall Motors' hybrid special engine
As of press time, there are two "hybrid special engines" of the "Great Wall Lemon Hybrid DHT System":
"1.5L hybrid engine": maximum power 75 kW (102 PS), peak torque of 135 N·m, using "Atkinson cycle", "compression ratio" reached 13:1;
"1.5T Hybrid Engine": Maximum power 115 kW (156PS), peak torque 235 N·m, using the "Miller Cycle".
Obviously, the "self-priming engine" is more focused on fuel saving, while the "engine" version with "turbocharging" is more performance-oriented.
"Hybrid special transmission": fixed shaft type, parallel layout, two-speed transmission
The "DHT" of the "Great Wall Lemon Hybrid DHT System" is named after the maximum power of the "drive motor" (TM motor), which is as follows:
Schematic diagram of Great Wall Lemon Hybrid DHT100
"DHT100": "Drive motor" power of 100 kW, torque of 250 N·m;
"DHT130": The power of the drive motor is 130 kW and the torque is 300 N·m.
Whether it is "DHT100" or "DHT130", "Great Wall Lemon Hybrid DHT" has similar structural characteristics:
Schematic diagram of the structure of the Great Wall lemon hybrid DHT
1. The shafting part of the "DHT" is arranged in parallel, so the "drive motor" can be connected to the "differential" through the reduction gear to achieve direct power output;
2. The "engine" can be directly connected to the "generator" through the deceleration of the first stage gear (1st gear in the picture above), and the "clutch" is provided to control the intervention of the "engine", while the "clutch" is controlled by the "electronic pump";
3. The "engine" can also be transmitted to the "differential" through a 2-speed transmission mechanism, enabling the "engine" to drive directly.
This two-speed shifting mechanism relies on the "synchronizer" for synchronization, which is the same as Geely Automobile's "Thunder God Intelligence Engine Hi · X Hybrid System" is one of the biggest differences.
Multiple modes of the Great Wall Lemon Hybrid DHT system (GIF)
Like the "DHT" which is also a "fixed-axis structure", the "Great Wall Lemon Hybrid DHT" has the most basic four modes, as well as a special mode of two-speed direct drive:
1. Pure electric mode: under low-speed working conditions such as urban congestion sections, the "engine" is in the low-efficiency range at this time, so it does not work, but the "drive motor" TM directly drives the wheels;
2. Series mode: When the battery power is low at low speed, the "engine" drives the "generator" to provide power for the "drive motor", while the "motor controller" controls the power flow to ensure that the "engine" is in the efficient working range, similar to the "extended range mode" of the "Honda i-MMD hybrid system";
Features of the Great Wall Lemon Hybrid DHT system
3. Parallel mode: in response to the situation of rapid acceleration and high power demand, the "engine" remains efficient while intervening in the total power output, while the "drive motor" is used as an auxiliary power;
4. Kinetic energy recovery mode: Under the condition of automobile deceleration and braking, the "drive motor" acts as a "generator" to recover the energy of friction and charge the "battery".
Engine direct drive mode
5. Engine direct drive mode: Under medium and high-speed working conditions, the "engine" is theoretically in the high efficiency range, and if the "tandem mode" is used at this time, the overall transmission efficiency will be reduced (explained in detail in the previous chapter), and the 2-speed transmission mechanism using the "Great Wall Lemon Hybrid DHT" can intervene at a speed of about 40 km/ h to improve fuel economy. Great Wall Motor officially declares that "the wheel end torque is about 1000 N·m greater than that of the single-gear series parallel architecture".
Great Wall Lemon Hybrid DHT system working conditions and working mode correspondence table
Overall feature: Highly integrated
Schematic diagram of the main components of the Great Wall Lemon Hybrid DHT system
Of course, the "Great Wall Lemon Hybrid DHT System" also adopts a highly integrated structured design, integrating the "DCDC system" and "motor controller" in the entire power module to reduce the volume of the powertrain, reduce the weight, improve the transmission efficiency, improve the NVH control and other effects, in line with the basic characteristics of the new generation of "DHT" mentioned in the previous chapter.
Two power architectures
The official explanation is "support for HEV and PHEV two power architectures", of course, some people can also understand that support two-wheel drive and four-wheel drive, we will expand later.
Two power architectures of the Great Wall Lemon Hybrid DHT system
The "HEV architecture" focuses on the economy of use in urban scenarios, which is reflected in the ultra-low fuel consumption of urban roads and the instantaneous acceleration ability of medium and high-speed road conditions, the comprehensive efficiency of the power system can reach 43% to 50%, equipped with the "battery" of the "Cataline Era" (CATL), which is characterized by a "battery" with high power and low internal resistance, and the "battery" has a power of about 1.75kWh, using an air-cooled structure, and a discharge power of 70.9kW.
In April 2021, the low-speed (15km/h) 100km/h fuel consumption of the electric Bond measured by WEY Macchiato DHT was 5.1L
In the official test, the comprehensive fuel consumption of the A-class SUV using the "HEV architecture" is as low as 4.6L, while the B-class SUV using the "HEV architecture" has a fuel saving rate of 35 to 50% compared with the fuel product, and the fuel saving rate is about 7.5s from 0 to 100km/h.
WEY Macchiato DHT-PHEV comes with a 5-year/150,000 km warranty
The "PHEV architecture" is equipped with a "battery pack" with a power of 13 to 45kWh, and the longest pure electric theoretical mileage of the 45kWh "battery pack" can reach 200km, supporting 11kW AC slow charging and DC fast charging, and officially announcing that it can be charged from 25% to 80% in 26 minutes.
Three powertrain combinations
The two architectures of "HEV architecture" and "PHEV architecture" extend three sets of powertrain combinations:
1. "1.5L hybrid special engine" + "DHT100": power system power 140 ~ 170KW, mainly used in A-class models;
2. "1.5T hybrid engine" + "DHT130": power system power 180~ 240kW, mainly used in B-class models;
3. "1.5T Hybrid Engine" + "DHT130" + "P4 Motor": Powertrain power 320kW, only for "PHEV architecture", mainly used in C-class models.
Schematic diagram of the four-drive force assembly layout of the Great Wall Lemon Hybrid DHT system
The rear axle "P4 motor" of the four-wheel drive model has an output power of 135 kW (184PS) and a torque of 233 N·m, and the maximum efficiency of the "motor" can exceed 96%, and the assembly mass is 75 kg.
WEY MOCHA DHT-PHEV challenges a 60% gradient
By adjusting the torque distribution between the front and rear axles (0:100~100:0), you can first adjust the attitude of the vehicle entering the bend, improve the stability of the vehicle handling, and reduce the probability of "push head" and "tail fling". In addition, it is officially announced that through this four-drive assembly, the maximum climb of 60% to 65% can be achieved on dry asphalt pavement, and the slope climb of 15% to 18% of snow roads can be achieved.
Increasing ground adhesion and improving climbing ability is the goal
The "DHT powertrain" on the front axle and the "P4 motor" on the rear axle work together to achieve a variety of working modes such as full-time all-wheel drive, timely four-wheel drive, and direct engine drive. For example, when facing ice and snow pavement, it will enter a full-time four-wheel drive mode, and the front and rear "drive motors" will be fully turned on to maximize the use of ground adhesion and prevent slippage.
Working mode of the four-drive force assembly of the Great Wall Lemon Hybrid DHT system (GIF)
In the face of muddy road conditions, the system switches to the timely four-wheel drive mode, the front axle drive force assembly is connected in series, the front and rear axle power intelligent switching, according to official information, the maximum torque of the front wheel side can reach 3000 N·m, and the maximum torque of the rear wheel side can also reach 2800 N·m, in order to achieve a difficulty.
Great Wall Lemon Hybrid DHT system family barrel layout
In general, the current "Great Wall Lemon Hybrid DHT System" provides different power options from 140kW to 320kW, which can support the flexible combination of different levels of models, and as far as the current product layout is concerned, the "PHEV package" of "high-power powertrain + large battery" will be mainly used for "WEY brand" models, especially the four-wheel drive version.
Fill in the short board: more efficient hybrid special engine
The new hybrid engine was released in June 2021
At the beginning of the article, we also said that the "Great Wall Lemon Hybrid DHT System" was established in 2018, and it is not easy to develop an efficient hybrid system in just a few years and put it into mass production. Therefore, Great Wall Motors' "Honeycomb Power" is also developing a "hybrid special engine" with higher thermal efficiency. In June 2021, "Honeycomb Power" took the opportunity of "the 10 millionth engine off the production line" and released a number of "hybrid special engines" for the "Great Wall Lemon Hybrid DHT System".
According to official data, one of the 1.5L naturally aspirated "engines" code-named 4G15H integrates a number of advanced technologies such as "electronic water pump", "low-pressure EGR", "high efficiency ignition", 4.5 bar "multi-point fuel injection", 13:1 "compression ratio" and "Atkinson cycle". From the parameter point of view, compared with the above-mentioned data, the 4G15H "engine" has a certain improvement in both maximum power and maximum torque, and most importantly, its thermal efficiency is expected to exceed 43%. The 4B15H will be installed in models such as "WEY Macchiato", "Haval Red Rabbit", "Haval First Love", etc., while the "engine" codenamed 4B15C will be installed on "Haval F7" and "Haval Big Dog" models.
History: The past of the "Pi4 Hybrid System"
Known as the "Bigmouth VV7", the WEY P8
Anyone who has studied Great Wall Motors' hybrid system should know that the "Great Wall Lemon Hybrid DHT System" is not the first hybrid system of Great Wall Motors, and when we turn the time back to the Beijing Auto Show in April 2018, we will find a model based on the first generation of the Great Wall "Pi4 Hybrid System" - "WEY P8".
The development of the Pi4 hybrid system
"WEY P8" equipped with the "Pi4 hybrid system" can be described as a lot of history, the project was launched in 2013, after 5 years of research and development and testing, and finally unveiled in 2018, "P" in the "Pi4 hybrid system" means "Plug-in" (plug-in hybrid), "i" means "Intelligent" (intelligent), and "4" means "4WD" (four-wheel drive). Judging from the motor architecture attributes of "WEY P8", it is a "P0 motor" + "P4 motor" separate motor architecture.
There is no mechanical connection between the front and rear axles
According to official data, the "WEY P8" is equipped with a 2.0T "engine" with a "P0 motor" (maximum power 15kW) on the front axle, and the "drive motor" on the rear axle has a maximum power of 85kW and can output a maximum torque of 195N·m, and in four-wheel drive mode, the zero-hundred acceleration score is 6.5s. CATL provides a "battery pack" containing 96 square-shell "battery cells", with a capacity of 12.96kWh, a pure electric endurance of 50km, and a vehicle endurance of 660km.
Very much like the structure of the BMW i8 (2015).
Friends who may have seen the previous chapters will think of a model we have introduced, the "BMW i8" (2015), the difference is that the "BMW i8" puts the powertrain of the fuel on the rear axle. Therefore, when I look through the list of suppliers of "WEY P8", we will find many familiar names: "motor" and "motor controller" from Siemens, "reducer" from Germany Schaeffler, "clutch" from Getrag, "hybrid controller" from "old player" Continental Group, "hybrid system software" is from the German Bosch Group.
With the switching of power sources, it is bound to bring a poor experience
However, the previous chapter also mentioned the shortcomings of the "P0P4 motor architecture", in addition to the possible poor experience brought by the power source switching, it is not conducive to optimizing the efficiency of the electromechanical coupling between the "engine" and the "motor", which seems to avoid the problems of the design and manufacture of the electromechanical coupling system, but in fact, it loses the core of the hybrid technology.
Fortunately, Great Wall Motors adjusted its direction in time, and the "Great Wall Lemon Hybrid DHT System" that clarified the technical logic was obviously on the right track. Finally, I hope that everyone, like me, will give a thumbs up to every domestic car company that has seriously developed a hybrid system, and it is precisely because of their tireless efforts that they can exchange for a blue sky in the future of China's automotive industry.