On May 28th, BYD officially launched two highly anticipated new models, the Qin L DM-i and the Seagull 06 DM-i. Alongside these vehicles, BYD unveiled its fifth-generation DM technology, which had been kept under wraps until now. Despite the secrecy, the company had previously hinted at some of the system's impressive capabilities, such as a combined driving range of 2,100 kilometers and a fuel consumption as low as 2.9 liters per 100 kilometers when the battery is depleted. This is a significant improvement over the DM4.0 technology, which offered a combined range of around 1,300 kilometers and a fuel consumption of 3.8 liters per 100 kilometers. So, how did BYD achieve this leap in performance?
To meet the goals of low fuel consumption and long driving range, BYD's fifth-generation DM technology focuses on three main areas: comprehensive upgrades to core components, optimization of software control strategies, and the application of all-weather vehicle thermal management. Let's delve into the details.
Comprehensive Upgrades to Four Core Components
BYD refers to the fifth-generation DM technology as the "electric-first power architecture." The three main components of the hybrid system—the dedicated hybrid engine, the EHS electric hybrid system, and the dedicated hybrid blade battery—have all been upgraded. Additionally, an innovative 12V lithium iron phosphate battery has replaced the traditional lead-acid battery.
1.Upgraded 1.5L Hybrid Dedicated Efficient Engine
- This new engine boasts a maximum power of 74kW and a peak torque of 126N·m, with a record-breaking thermal efficiency of 46.06%, certified by the China Automotive Technology and Research Center. This high thermal efficiency is achieved through seven core technologies, including a 16:1 compression ratio, high swirl intake port design, high-energy ignition system, intelligent fuel injection system, pre-catalyst exhaust gas, intelligent split cooling, and a variable displacement oil pump. These enhancements contribute to better combustion efficiency and lower energy consumption.
2.EHS Electric Hybrid System
- The overall efficiency of this system has increased from 87.6% to 92%, and its power density has improved from 65kW/L to 75kW/L. By optimizing internal structures and materials, such as using ball and column bearings, high-efficiency clutches, low-viscosity lubricants, and ultra-thin silicon steel sheets for the motor, energy loss along the flow path has been significantly reduced.
3.Dedicated Hybrid Power Blade Battery
- Designed to balance power and energy density, this battery offers a 15.9% increase in energy density over the previous generation. It features a discharge rate of up to 16C and a feedback power of 5C, enhancing both power and energy efficiency. The battery's weight has been reduced, further improving range and stability.
4.12V Lithium Iron Phosphate Starter Battery
- This small but innovative battery is more compact than traditional lead-acid batteries, requires minimal maintenance, and can last up to 15 years. It also saves approximately 0.1 liters of fuel.
Optimization of Software Control Strategies
The fifth-generation DM technology employs a seven-in-one power domain controller, integrating components such as the voltage control unit, dual motor control unit, DC boost module, onboard charger, DC converter, and power distribution unit. This integration reduces the size of the controller components, shortens communication paths, and enhances overall vehicle performance by doubling processing power.
All-Weather Vehicle Thermal Management
Thermal management is divided into battery thermal management, front cabin thermal management, and cabin thermal management.
1.Battery Thermal Management
- The blade battery uses a direct cooling technology that channels air conditioning refrigerant directly through the battery, offering high cooling efficiency with low energy consumption. The second-generation battery direct cooling system features a cross-flow channel design to improve temperature uniformity and active heat exchange control.
2.Front Cabin Thermal Management
- Engine and motor warm-up times are reduced through upgraded electronic control systems.
3.Cabin Thermal Management
- Enhanced compressor efficiency and reduced heat exchanger air resistance enable faster temperature adjustments in both summer and winter, improving comfort and reducing energy consumption. In extreme temperatures, these upgrades can save 0.07 liters of fuel for heating and 0.13 liters for cooling.
Conclusion
Through a series of hardware and software upgrades, along with a low drag and low rolling resistance vehicle design, and an increased fuel tank capacity of 65 liters, BYD's fifth-generation DM technology achieves remarkable energy consumption and range figures: an NEDC fuel consumption of 2.9 liters per 100 kilometers and a CLTC power consumption of 10.7 kWh, resulting in a combined range of 2,100 kilometers. This impressive performance sets a new standard, putting significant pressure on fuel vehicles from joint ventures.
