How can Yaoguang C-DM bid farewell to the shortcomings of plug-in mixer?

In the "2023 Chery Technology Day", Chery showcased the latest technological achievements under the "Yao Guang 2025" strategy, covering multiple fields such as platform architecture, powertrain, three electric vehicles, and intelligent driving. Based on these technological innovations, Chery is full of confidence in the new energy field. In the fourth quarter of this year, there will be a dense release of five super hybrid 3.0 products, among which the "golden content" is undoubtedly the Xingtu Yaoguang C-DM.

As a high-end brand of Chery, Xingtu can be said to be the epitome of "Technical Chery", and Yaoguang is also a strategic model of Xingtu brand. The Yaoguang C-DM released this time can be described as "a collection of Chery's thousands of pet cars" in terms of technology. The first launch is equipped with a hybrid dedicated engine and dual electric three speed DHT, which not only provides consumers with more choices, but also will form a new impact on the hybrid SUV market.

Hybrid dedicated engine to further reduce fuel consumption

Dare to make such a conclusion, technology is naturally the key to Yaoguang C-DM. For example, it is equipped with a brand new hybrid dedicated engine.

There is a numerical value that sparked my strong curiosity: the engine's thermal efficiency is 44.5%.

If I remember correctly, this should be the highest thermal efficiency value in the era of internal combustion engines. As early as 2019, when the Mazda 2.0L self priming engine achieved a thermal efficiency of 43% through compression ignition technology, it was hailed as an industrial miracle. In 2020, when BYD, a car company focused on new energy, developed thermal efficiency to 43%, it was also astonishing.

But the thermal efficiency of the BYD DM-i super hybrid 1.5L hybrid engine, which is 43%, is somewhat "ineffective". It sacrifices performance, such as canceling direct injection and VVT technology in the cylinder and focusing on reducing thermal efficiency, achieving a value of 43%.

What shocked me about the Yaoguang C-DM is not only its 44.5% thermal efficiency value, but also the lack of compromise in performance of this hybrid engine, which is a turbocharged engine.

Compared to naturally aspirated engines, turbocharged engines with the same displacement have increased energy consumption in the intake and exhaust due to the addition of turbochargers. The absolute value of thermal efficiency is often lower than that of self aspirated engines. However, the Yao Guang C-DM hybrid special engine achieves higher thermal efficiency values than the DM-i super hybrid engine without performance degradation and with a turbine, indicating its leading technical strength in the engine field.

And all car companies are passionate about improving engine thermal efficiency, with only one goal - to reduce fuel consumption. In theory, for every 1% increase in engine thermal efficiency, the comprehensive fuel consumption per 100 kilometers can be reduced by about 0.1L, and it is directly proportional to the weight of the vehicle. The larger and heavier the vehicle, the higher the thermal efficiency and the more significant the fuel saving.

For hybrid mid size SUVs like the Yaoguang C-DM, the higher thermal efficiency of hybrid dedicated engines can undoubtedly further reduce the overall fuel consumption and bring lower vehicle costs. According to the official statement, the lowest comprehensive feed fuel consumption of Yaoguang C-DM is only 5.4L per 100 kilometers, which is lower than the Tang DM-i (with a minimum feed fuel consumption of 5.5L per 100 kilometers).

Moreover, according to the plan, the future Yaoguang C-DM will also be equipped with Chery DHE 6.0 hybrid dedicated engine, which is the sixth generation engine. With a compression ratio of up to 17:1 and active pre combustion jet technology, the thermal efficiency of the Yaoguang C-DM will exceed 45% or even 46% by accelerating combustion speed, improving isovolumetric capacity, reducing heat loss, and suppressing detonation, which may become a new technological milestone for internal combustion engines.

Double motor three speed DHT, bid farewell to plug-in hybrid short board

In addition to the hybrid dedicated engine, the DHT hybrid dedicated gearbox is another technical challenge for plug-in hybrid systems

Taking the DM-i super hybrid, which currently has the highest market share, as an example, it is a single gear direct drive with simple structure, low maintenance costs, and low daily commuting fuel consumption. However, when powered, accelerating rapidly, and driving at high speeds, the DM-i with only one gear transmission is difficult to ensure that the engine operates in the optimal efficiency range, resulting in an increase in fuel consumption; At the same time, the hybrid system using a single motor power source, although accelerating faster than gasoline cars of the same class, still has a significant performance gap compared to pure electric vehicles.

But Yaoguang C-DM has brought a new structure - dual motor drive+three speed DHT.

Let's start with dual motor drive.

It should be noted that dual motor ≠ dual motor drive. At present, most DHT structures in China have two motors, but only one of them is responsible for driving the vehicle. The other motor is dedicated to generating electricity and charging energy during extended range mode, or driving the engine during parallel acceleration, without directly driving the wheels.

The advantages of a single motor drive are compact structure, low cost, and relatively simple software control. However, the drawbacks are also obvious. Firstly, the acceleration performance is weak, and secondly, it is difficult to achieve the highest motor efficiency.

But Yaoguang C-DM dual motor drive can improve acceleration performance, especially the explosive power during the starting and early stages of acceleration; At the same time, the combination of two motors can make the entire hybrid system easier to operate in the high-efficiency range, which is similar to the increasingly popular multi-core processors on mobile phones.

There are three more DHT gears.

Currently, among the popular DHT technology routes, the Honda i-MMD and BYD DM-i super hybrid have only one gear, whether it is motor driven or engine directly connected. The principle of the Great Wall Lemon DHT is similar to the previous two, except for the addition of a two speed gearbox at the engine output end.

This structure, in actual driving, can only output power with a fixed gear ratio in one gear, making the engine a bit like a bicycle without a transmission. If the speed is faster, it will not work hard, and climbing and accelerating quickly will be very tiring. So when this type of hybrid is used in high-speed engine direct drive cruising, it is easy to exit the direct drive mode and switch to electric motor drive with slight acceleration and deceleration. This not only results in poor power experience, but also reduces efficiency. The final result is that the measured fuel consumption at high speeds is not ideal.

The Yaoguang C-DM, which has three gears, can not only work longer in the high-efficiency range during engine direct drive, reducing fuel consumption during high-speed cruising, but also cooperate with dual motors to cover more commuting environments for users through 9 efficient working modes and 11 combined gears, achieving early recognition of driving conditions and intelligent optimization of traffic; At the same time, it can further improve the efficiency of the motor, thereby optimizing the efficiency of this hybrid system. In fact, the driving system of Yaoguang C-DM has the highest transmission efficiency of over 97.6%.

It can be said that under the technical structure of "dual motor drive+3-speed DHT", the Yaoguang C-DM effectively avoids the shortcomings of the current mainstream plug-in hybrid, while taking into account the low fuel consumption in urban areas, it not only reduces high-speed commuting fuel consumption, but also brings stronger power performance.