JJE’s New Solution for High-Efficiency, High-Capability eAWD
Dr. Yang Cao, Transmission Manager, JJE Technologies
JJE Technologies proudly presents the DL Combo™, the industry’s first fully integrated disconnect and locker differential system. By combining eDisconnect and eLocker functionalities into a single, compact unit, this innovation provides electrified all-wheel-drive (eAWD) vehicles uncompromised off-road capability and low energy consumption.
Introducing the DL Combo™ Differential
JJE launched its DirectFlux™ eLocker in 2021, now in use by several OEMs including in the newly introduced Beijing Automotive BJ60e and BJ40e extended-range off-road SUVs. This eLocker utilizes JJE’s unique electromagnetic clutch technology to lock up 6000 Nm of half-shaft torque within just 70 milliseconds.
JJE’s Disconnect & Locker Combo Differential, or DL ComboTM Differential
In 2022, JJE introduced the DirectFlux™ eDisconnect, offering both mono-stable and bi-stable configurations. This system enables real-time AWD/2WD switching at any vehicle speed, improving energy efficiency and electric range by 7–10 %.
Now, with an innovative, highly integrated mechanical design, JJE’s new DL Combo™ Differential merges these two systems into a compact differential with the same envelope as a conventional differential − making it fully interchangeable for OEM applications.
Compact. Capable. Integrated.
The DL Combo™ features a deeply integrated, nested mechanical structure that leverages JJE’s DirectFlux™ electromagnetic clutch configuration. As a result, the DL Combo™ differential maintains the same envelope as a conventional unit while offering dual functionality − eDisconnect and eLocker − within a single package.
Compared to standalone solutions, this design allows standard layout, significantly reducing the complexity and weight of the eDrive system with such dual functions. It allows vehicle OEMs to offer different drivetrain functions − conventional, disconnect only, locker only, or combined disconnect and locker − with standard mechanical interfaces.
JJE’s eDifferential Family & Roadmap
For OEMs, balancing efficiency against off-road and dynamic capabilities has long been a challenge. JJE’s DL Combo™, built upon its proven DirectFlux™ clutch technology, eliminates that offering below features:
- eDisconnect for 4×2 mode and drag loss reduction
- eLocker for 4×4 mode with 100 % torque transfer and maximum traction
Already validated in production vehicles, the DL Combo™ marks a major leap in electrified drivetrain systems.
Ideal for Secondary Axles
The DL Combo™ is especially suited for secondary drive axles − for instance, enabling a 4×4 off-road SUV to seamlessly switch to 4×2 for efficiency, while maintaining full locking capability when additional taction is needed.
Technical Breakthroughs
The DL Combo™ integrates two subsystems:
- eDisconnect: Electronically decouples the secondary axle in <70 milliseconds, reducing drag losses by up to 95 % and increasing electric range by 7 − 10 %
- eLocker: Delivers rigid locking between left and right half shafts for full torque transfer − even in extreme off-road scenarios
Both functions can be configured as bi-stable or mono-stable, depending on application needs. Two typical configurations meet different functional safety targets:
- Front axle: Bi-stable eDisconnect + Mono-stable eLocker. The bi-stable eDisconnect is fail-safe. It keeps the system in the state that the vehicle needs at the moment of failure, e.g., loss of 12V power supply. The mono-stable eLocker lets the front secondary axle default to open in case of a failure − the vehicle will be easier to steer when unlocked, but the vehicle will lose front axle’s power.
- Rear axle: Bi-stable eDisconnect + Bi-stable eLocker. eLocker’s bistable function allows the differential to stay locked for torque safety, which is especially important under critical conditions such as climbing rocky steep grade and pulling up heavy trailer on low-traction surface. This configuration is ideal for rear axle, which bears more driving force, and does not affect steering when locked up.
One additional benefit of bi-stable device is energy efficiency − the bi-stable electromagnetic clutch does not require any current to hold its state, enhancing system’s efficiency.
The DL Combo™ can be applied to provide several practical driving modes based on the vehicle’s need:
- 4×2 Mode (Economy): the eDisconnect disengages the secondary axle, eliminating the drag and maximizing efficiency. A mechanical interlock ensures the eLocker will not engage accidentally.
- 4×4 Mode (Sport): the eDisconnect in the secondary axle is engaged, but the eLocker stays open. This is the normal 4×4 mode.
- 4×4 Locked Mode: With the eDisconnect engaged, the eLocker is further engaged to secure the axle’s traction.
Vehicle Test
The DL Combo™ has been successfully demonstrated in the Beijing Automotive BJ40e, China’s iconic off-road SUV. The vehicle demonstrated 7 − 10 % EV range improvement by seamlessly switching between 4×2 and 4×4 at any speed. The offroad capability remains uncompromised as the eLockers function when needed.
BJ40e Test Vehicle with JJE’s DL ComboTM Differential & Drag Loss Chart
Setting a New Benchmark for eAWD
By addressing both efficiency and capability, the DL Combo™ Differential enables automakers to offer the next generation of electrified AWD with best-in-class efficiency and uncompromised traction security.
