＂Judging＂ the trend of electric power, Great Wall has researched the value geometry of the first longitudinal 9AT gearbox in China.

Judging from the current situation, independent brands have made many breakthroughs in engines, and the better gearbox configuration is still "all-in-one" Aisin 8AT/ Aisin 6AT. The technical difficulty of independently developing high-quality and high-end gearboxes can be seen.

The difficulty doesn’t mean that no one has tried. In December last year, the 3.0T+9AT powertrain independently developed by Great Wall Motor officially rolled off the assembly line. As the first domestic vertical 9AT gearbox, many friends are full of curiosity about it. In this article, we will focus on this and see how strong this domestic 9AT is in all aspects.

First, the introduction background of Great Wall 9AT gearbox

Under the general trend of electrification becoming the mainstream, some people may question why Great Wall should spend great efforts to develop 9AT transmission.

In my opinion, there are three main reasons:

First,Meet the needs of its products. Great Wall Motor has always adhered to a diversified powertrain technology route. In addition to SUVs and cars, off-road and pickup trucks such as Tank 300 and Great Wall Gun under Great Wall have also brought good sales support, and it is also doomed that Great Wall will not be across the board on internal combustion engines.

In order to enhance the competitiveness of products and the subsequent development of off-road and pickup trucks, Great Wall really urgently needs a powertrain suitable for itself. A high-powered 3.0T engine is undoubtedly the optimal solution, and only the hydraulic automatic transmission (AT) is matched with it.

Second,No longer restricted by suppliers. Previously, Haval H9, Tank 300 and other models were all equipped with ZF 8AT imported from abroad, but their own brands were "stuck in the neck" by foreign companies not once or twice. When the ZF8AT of Tank 300 was adjusted, ZF engineers were needed to cooperate, and people were unwilling or charged sky-high prices, so the Great Wall could only admit that it was unlucky. In order to get rid of the situation of being controlled by people, self-developed technology is the real breakthrough point to seek change.

Third,Raise the brand image. Undoubtedly, the surge of independent brands is definitely the future trend. It is not difficult to see from the current situation that the price of tanks 300 and 500 approaches 300,000-400,000 yuan. Great Wall Motor has a determination to move forward and impact the high-end passenger car market. Great Wall, a vertical 9AT gearbox, can be said to make up for the gap in the field of high-end gearboxes in China, and the high-end product strength can naturally support the high-end brand image.

Simply relying on foreign mining technology can’t get more recognition. In order to support the ambition and ambition of the brand, the three major technologies of independent research and development and high quality are the optimal solutions, and the launch of the 3.0T+9AT powertrain is also a trend. This power system will be installed on more high-end models in the future, helping Great Wall Motor to launch brand challenges and impacts.

2. Which engines does 9AT gearbox mainly cooperate with? On which models?

Because it is a new technology developed by Great Wall Motor, the time for mass production off the assembly line is not long, so at present, there is only a power form of 3.0T V6 turbocharged engine+longitudinal 9AT gearbox, which will be put on a tank 500 for the first time. Naturally, Great Wall Motor also wants to put this power system on more high-end models as soon as possible, but what comes with it is the capacity problem.

Yongchuan Parts Base was just completed and put into operation in December 2021. The annual output of 9AT automatic gearbox project is only 180,000 sets, while the order quantity of tank 500 reached 40,000 only after one week of pre-sale. The capacity supply of a single model can be maintained, let alone applied to tank 300 with a monthly sales of nearly 10,000. According to the official, after the production capacity is improved, this efficient power system will be applied to more vehicles in the future, including off-road, pickup trucks and light passengers.

Iii. Structural Analysis of 9AT in the Vertical Position of the Great Wall

Mercedes-Benz 9AT, as the world’s first mass-produced longitudinal 9AT transmission, can be described as the "originator", and the Great Wall 9AT transmission is also inextricably linked with him. Gerhard Henning, a research and development engineer hired by Great Wall at a high salary, is the main designer of Mercedes-Benz 9AT.

Like Mercedes-Benz 9AT, the vertical structure makes the Great Wall 9AT transmission have ample internal deployment space, so it can meet the needs of four sets of planetary gear sets. Each set of planetary gear sets includes planetary gears, sun gear and planetary row racks, and the three components are embedded with each other. The transmission ratio can be adjusted by changing the setting and combination of multiple sets of planetary gears.

The whole system consists of four sets of planetary gear sets, four clutches and two brakes, and nine forward gears, one neutral gear and one reverse gear are realized through the state combination of each clutch. Aisin’s vertical 8AT also adopts the structure of "4+4+2", but it has one less forward gear than the Great Wall 9AT.

In addition, all gears of Great Wall 9AT are coaxial. Compared with the traditional double-shaft structure, it reduces the meshing friction between gears without bearing radial force, reduces the risk of micro-deformation and saves the internal space of the transmission.

Fourth, the technical characteristics of the Great Wall longitudinal 9AT

As we all know, the rugged terrain in the mountains makes off-road vehicles have very high requirements for engine torque transmission. Therefore, the Great Wall 9AT gearbox is specially tailored based on the off-road working conditions of tank models, which can meet various complex terrain such as mountains, urban areas, steep slopes, mud and deserts, and realize full working condition load spectrum coverage.

And locking can be realized in the first gear, and the torque at the wheel end of the low gear is sufficient, thus achieving better torque output. However, it is very difficult with the current technology, which requires the durability of the torque converter and friction plate to be high enough to ensure the long-term stability of the gearbox. Therefore, the Great Wall 9AT is equipped with a hydraulic torque converter with flexible output, which improves fuel economy and gives consideration to better comfort.

At the same time, in order to improve the maximum torque, the Great Wall 9AT transmission adopts compact and efficient clutch design, intelligent integrated electro-hydraulic module and other technologies, achieving a breakthrough in transmission performance, and achieving a transmission bearing capacity of up to 600N·m while ensuring the controllable transmission size, which is more advantageous than the general 9AT with a maximum bearing torque of 400 N m..

While having high performance, Great Wall has not forgotten to reduce noise. The structural design of the internally integrated Damper shock absorber makes Great Wall 9AT have better NVH performance.

In addition, in order to meet the needs of more vehicles, the overall structure of the Great Wall longitudinal 9AT is very compact, with an axial dimension of 624.8mm and a weight of only 95kg, and efforts have been made in miniaturization and lightweight. It can match the torque requirements of different engines such as 2.0L and 3.0L gasoline engines or diesel engines, and is suitable for different models such as medium and large SUVs, pickups and cars.

In order to improve the matching and control performance, the control module TCU of Great Wall gearbox adopts integrated design and is directly connected with the solenoid valve. Compared with the traditional external TCU, it has stronger protection performance and shorter response time. Moreover, in order to protect the TCU, which is called the core brain of the gearbox, the Great Wall 9AT gearbox puts the TCU control unit and the slide valve box together and arranges them at the bottom of the gearbox oil pan. The advantage of this is that even if the chassis is flooded, it will not affect the internal structure and has more reliable stability.

V. Cross-evaluation of commercially available 9AT gearbox

At present, 9AT transmissions on the market include many brands, including ZF 9AT and GM 9AT horizontally, KATE9AT vertically, Gateke 9AT transmissions and Mercedes 9AT vertically. As the "first" of its own brand, what is the difference between the longitudinal 9AT transmission developed and designed by Great Wall and other 9AT transmissions on the market?

As we all know, measuring the quality of a gearbox is nothing more than the transmission ratio range, which represents the allowable speed range of a gearbox. The larger the ratio, the better the acceleration performance at low speed, and the lower the speed as much as possible at high speed cruise to achieve better fuel economy. We compare all kinds of 9AT transmissions mentioned above, and visually present the data analysis in the form of table: (GATE can lack 9AT data)

From the above table, it is not difficult to find that, as the world’s first transverse 9AT gearbox, ZF 9AT has the largest transmission ratio range, and its fuel economy should be the highest in theory. However, in fact, due to the design of four overdrive gears, ZF 9AT still can’t get up to the 9th gear at 120KM/h in actual use, which is also a point criticized by people, and it is not practical for domestic speed-limited roads.

(ZF 9AT)

Mercedes-Benz 9AT, which followed closely, learned this lesson. The transmission ratio range of this first mass-produced vertical 9AT gearbox is 9.15:1, which is smaller than that of ZF. In both economy and comfort modes, it starts in second gear by default. Both fuel economy and power can be taken into account in the use process, but the market response is not very good, and quality-related complaints are often received.

(Mercedes-Benz 9AT)

The transmission ratio range of the universal 9AT is only 7.56:1. Theoretically speaking, the ride comfort is better, and the acceleration at low and medium speed is better. However, the fuel economy is not dominant in the high-speed cruising state, and it only improves the fuel economy by 3% compared with the previous generation of universal 6AT, mainly because most American cars are matched with high-power engines. In order to keep up with the violent power performance, it is naturally not economical.

(Universal 9AT)

However, the first gear ratio of Great Wall 9AT is 5.288, and the torque output is more adequate in the low gear. The speed ratio range of the transmission is 8.843, and the gear ratios are relatively dense, and the shift smoothness is better. It is not difficult to see that a balance has been achieved between power performance and fuel economy. According to the official introduction, Great Wall 9AT can be put into the highest gear at 90KM/h, and the 7th, 8th and 9th gears of the high gear are all overdrive gears.

(Great Wall 9AT)

Generally speaking, the above-mentioned transmissions are common types at present, each with its own advantages and disadvantages. GM 9AT has a consistent American style, paying more attention to power performance, while the fuel economy is low. ZF 9AT, on the other hand, pays more attention to fuel economy, but the German road regulations are different from those in China, so the ninth gear is useless. Mercedes-Benz 9AT has achieved a balance between power and fuel economy, but the quality reliability needs to be improved. The Great Wall 9AT also gives consideration to power and economy, and its quality performance needs further testing in the market.

6. What is the current market evaluation?

The most intuitive performance of the transmission is the consumer’s experience and market reputation. However, 9AT is a new technology, and only one model of Tank 500 is equipped with this power system at present. Due to the epidemic and other reasons, the delivery time has been delayed, and the consumer’s experience is not yet known.

However, we can take the test drive experience of relevant media as a reference: we can feel the lightness of power during driving, the movement of shifting gears is relatively small, and there is room for improvement in response sensitivity when following the car at low speed. This is also a common problem of 9AT, which feels smooth when driving at high speed, but on complex urban roads, the power and economic advantages brought by 9A wide speed ratio will be discounted.

In addition, the speed will be maintained at about 1500rpm during normal driving, and it will reach 2000rpm when the speed reaches 120KM/h, so the overall training tends to fuel economy. Because the first gear ratio is 5.288, and the speed ratio range of the transmission reaches 8.843, there will be no phenomenon of high gear in name only.

However, from the past experience, transmissions often have advantages and disadvantages, such as Mercedes-Benz 9AT and ZF 9AT. Although the data performance is bright, the market performance is criticized. Whether the Great Wall 9AT transmission is really feasible still needs a lot of time and market tests.

Seven, 9HAT helps hybrid layout

At present, it is undoubtedly in the process of electrification transformation. Perhaps many people will wonder why Great Wall Motor has to spend so much effort to study a 9AT gearbox that is the icing on the cake.

Great Wall naturally thinks about whether it is necessary to study the transmission of fuel vehicles in the electrification era. Therefore, when the 9AT gearbox came out, Great Wall Motor also brought a 9HAT transmission, which is also the first P2 hybrid vertical 9-speed hydraulic automatic transmission in China.

The 9AT has 3 clutches +2 brakes in total, and the 9HAT is equipped with 6 clutches +2 brakes. On the basis of the 9AT transmission of Great Wall Motor, a 150kW high-power P2 hybrid motor and a C0 clutch structure for disconnecting or combining the transmission with the engine power are added, with a length of 720.8mm and a torque carrying capacity of 750N·m, which can achieve full load spectrum coverage.

All along, hybrid vehicles are a very important part of Great Wall Motor’s overall strategic layout. At the product level, Wei Pai, a high-end brand, has built a full-range hybrid architecture, and launched Mocha DHT-PHEV, Latte DHT and Macchiato HEV, achieving a comprehensive layout from A-level to D-level.

On the technical level, a series of power system products, such as lemon hybrid DHT, 4N20 2.0T+9DCT/9HDCT, P4 three-in-one pure bridge and so on, have emerged one after another, forming a perfect layout with system power ranging from 35kW to 320kW and system orientation ranging from energy saving to performance. The addition of the 3.0T+9AT/9HAT super powertrain will undoubtedly help Great Wall Motor to take a new step in the hybrid field and launch an impact on the high-end brand.

Write at the end:

With the development of electrification, perhaps few car companies are willing to invest a lot of energy in the research and development of transmission technology. Therefore, the appearance of the Great Wall 9AT technology is really rare, which makes the domestic gearbox reach a new height.

Whether domestic 9AT can replace foreign technology is still an unsolved problem at present, because the products have not been delivered in large quantities, and there is a lack of market evaluation. The specific experience, defects and quality need to be further verified. In addition, if Great Wall chooses closed technology only for its models, independent brands will probably continue to adopt 8AT for a long time to come.