It can be said that with the rapid development of new energy technology, Chinese automakers are showing significant competitiveness and market confidence through their unique hybrid technology. As a member of the domestic independent brands, SAIC Roewe officially launched its innovative DMH technology brand at the symbolic moment of the 8th China Brand Day. It can be said that this move is not only a self-demonstration of SAIC Roewe's technical strength, but also a sign of its active layout and competitive posture in the global hybrid vehicle market.
What is DMH? Let's start with the common plug-in hybrid system.
Put simply, plug-in hybrid (PHEV) systems are designed to combine the long-lasting power of a traditional internal combustion engine with the clean and efficient power of an electric motor. This system uses an ingenious coupling mechanism to enable the two power sources to work together. The core components of a PHEV include an engine, gearbox, drive motor, coupling system, and an integrated electronic control unit designed for hybrid power, which precisely manages the synergy between the combustion engine and the electric motor.
At present, there are three main PHEV technology solutions that are popular in the market: P1+P3, P2 and E-CVT. The P1+P3 and P2 schemes have some structural similarities, and they both rely on an independent motor to handle the power coupling task. The key to distinguishing between P1+P3 and P2 is the layout of the motor. The gearbox in the PHEV system has a completely different design concept compared to the conventional gearbox. The design of this gearbox is simple and efficient, consisting of three main shafts: the first shaft is responsible for receiving the power input from the engine, the third shaft is responsible for delivering power to the drivetrain, and the second shaft acts as an intermediary between the two.
It is worth mentioning here that in the nomenclature of PHEVs, the "P" stands for the electric motor (Power), and the number after it indicates which axis the motor is mounted on in the gearbox. For example, in the P1+P3 scheme, two motors are mounted on the first and third axes respectively; In the P2 solution, the motor is mounted on a second axis.
Therefore, the P1+P3 solution is favored because it effectively solves the vibration problem that may occur during power coupling through the design of two independent motors, and at the same time can enhance the torque output of the engine and support pure electric mode driving. In addition, the design is easier to adjust and maintain. Therefore, in the current field of automobile manufacturing, the P1+P3 scheme is widely adopted by many manufacturers because of its comprehensive performance advantages.
However, in the current plug-in hybrid (PHEV) system, although the P1+P3 motor configuration is common, there are some obvious shortcomings, especially in the design of the P1 motor. The P1 motor is responsible for not only the unstable torque of the oil filter (internal combustion engine), but also to increase its torsion, and to assist in driving the vehicle under certain operating conditions. As a result, the P1 motor is bulky, usually connected to the gearbox by a short shaft and transmission gear, in an external form known as an off-axle P1 motor.
However, the design of off-axis P1 motors introduces efficiency degradation and vibration problems. The additional propeller shafts and gears not only reduce the efficiency of the mechanical transmission, but also cause a coupling time difference between the torque output of the diesel engine and the P1 motor, which in turn causes vibration. This vibration is not only perceived by the occupants as discomfort when the engine is intervened, but also affects the long-term stability of the plug-in hybrid system.
SAIC's DMH super hybrid system cleverly solves these problems by adopting a coaxial P1 motor design. This design abandons the traditional cylindrical motor in favor of a direct-drive motor structure similar to a drum washing machine, mounted directly at the end of the P1 gear. The power output from the crankshaft of the P1 engine is directly transmitted to the coaxial motor through the clutch, and after preliminary filtering, the torque is directly applied to the motor rotor, and then the motor filters and increases torque, and finally transmits to the input shaft gear.
The design of the coaxial P1 motor significantly improves NVH (noise, vibration, and harshness) performance, eliminates perceptible vibrations for the occupants, enhances the long-term operational stability of the P1 axis, and also solves the problem of traditional P1 motors in the layout of the engine compartment. In terms of actual driving experience, the Roewe D7 DMH model provides a virtually non-perceptible power intervention experience when the engine intervenes at low speeds, thanks to the structural advantages of the coaxial P1 motor in eliminating the torque coupling time difference.
In terms of engine, the system is equipped with a 1.5-liter hybrid-specific engine, which incorporates a number of advanced technologies to improve its performance and efficiency. First of all, in terms of combustion efficiency, the turbulent kinetic energy and combustion rate of the engine have been significantly improved through the high tumbling ratio air duct and compact combustion chamber design. Specifically, the high-tumble airway technology increased the tumble ratio by 64 percent, while the matching optimization of the combustion system (compression ratio of 16:1) increased turbulent kinetic energy by 23 percent. These improvements help to improve combustion efficiency and reduce energy losses, which in turn enhances the engine's power output and fuel economy. In terms of thermal management, the engine adopts advanced technologies such as electronic water pump, double thermostat, and double-layer water jacket for cylinder head to ensure that the engine can be maintained at the best working temperature under different working conditions. In addition, the integrated design of the mechatronic twin oil pumps enables precise control of the cooling and oil output throughout the day, further improving fuel economy and performance. For example, when driving at low speeds, the electronic oil pump intelligently supplies fuel to enhance the acceleration ability; At high speeds, the electronic oil pump is intelligently turned off, and only the mechanical oil pump is used for oil supply, saving more than 40% of the energy consumption of the gearbox hydraulic system.
Finally, in order to further improve engine efficiency, reducing system friction is also key. The engine features up to 18 friction-reducing technologies in the piston/cylinder bore, crankshaft system, valvetrain, chain system, lubrication system and accessory system, and the cumulative effect of these technologies results in a thermal efficiency of 43 percent, which is quite remarkable in the industry. Through the application of these innovative technologies, the DMH super hybrid system not only improves the power performance, but also achieves excellent fuel economy and environmental performance.
Finally, at the core of the hybrid system, the DMH super hybrid system uses a highly integrated five-in-one PICU controller, which is equivalent to the "brain" of the hybrid system. The controller integrates five functions: motor control, engine control, hybrid transmission control, air conditioning thermal management and battery thermal management, to achieve comprehensive and refined control of the hybrid system.
By adopting a higher level of integration design, the 5-in-1 PICU controller not only achieves a significant reduction in physical volume, according to official data, compared with the previous generation of redundant components by 70%, making the whole structure more compact. In the comparison of the parts shown at the scene, the reduction in volume is obvious.
In addition, the integrated design also brings a significant reduction in the in-vehicle network load and data transmission latency. This optimization is significant for improving the computing speed of the system, which is said to be a 50% increase compared to the previous one. In the actual vehicle application, this improvement is directly reflected in the acceleration of the power response. Taking the Roewe D7 DMH as an example, its power response time has been shortened to just 0.26 seconds, providing users with a faster and smoother driving experience. This attention to detail not only enhances the overall performance of the hybrid system, but also further enhances driving comfort and responsiveness.
It can be said that with the grand launch of the DMH technology brand, SAIC Roewe has taken a firm and important step in the field of hybrid technology. The launch of this technology brand is not only the crystallization of SAIC's more than ten years of technology accumulation, but also an innovative breakthrough in the integration of traditional fuel vehicles and electric vehicle technologies.
Of course, China's hybrid market has huge potential and unlimited possibilities. Compared with mature markets such as the United States, Japan, and Europe, the demand for plug-in hybrid technology in the Chinese market is more urgent. The unique market environment and user needs provide unique opportunities for automotive companies to develop in the field of plug-in hybrid technology. With its advanced plug-in hybrid technology, SAIC Roewe provides a practical mobility solution for Chinese consumers.
Looking back at the development history of SAIC Roewe, its focus and persistence in hybrid technology are obvious. As early as 2010, SAIC Motor invested in the research and development of plug-in hybrid technology in a forward-looking manner, positioning it as a long-term development technology direction. After years of technical precipitation and market practice, SAIC Roewe has formed obvious technical advantages and distinctive brand characteristics. The launch of the DMH technology brand has undoubtedly pushed SAIC Roewe's hybrid technology to a new peak.
The advent of DMH super hybrid technology not only demonstrates SAIC Roewe's latest achievements in the field of hybrid technology, but also reflects its strength and self-confidence as a Chinese automobile company. In the context of the era of new energy vehicles, SAIC Roewe is leading Chinese auto brands to the global stage with its unique hybrid technology.
It is worth mentioning that at this brand conference, the official also announced that the Roewe D5X DMH will be launched on May 20, and the iMAX8 DMH will be launched in the fourth quarter.
Among them, the Roewe D5X DMH opened pre-sales at the Beijing Auto Show, with a pre-sale range of 119,800-146,800 yuan. The new model will be equipped with the Roewe DMH super hybrid system, a 1.5-liter turbocharged hybrid engine, and a CLTC pure electric range of 135 km and a CLTC comprehensive range of 1,300 km.
Therefore, looking forward to the future, with the continuous progress and wide application of hybrid technology, we have every reason to believe that SAIC Roewe will continue to make an important contribution to the vigorous development of China's automobile industry with its excellent technical strength and innovative spirit. At the same time, we also hope that more Chinese auto companies can devote themselves to the research and application of hybrid technology, and jointly promote the prosperity and progress of China's auto industry.