Maintaining traction
Haldex develops efficient all-wheel drive system for electric vehicles
James Scoltock in News.
- Published in News.
Haldex tested its first generation electric all-wheel drive system in a Saab 9-3
Haldex is developing an electric all-wheel drive system which includes torque vectoring, for hybrid, plug-in hybrid and pure electric vehicles. Haldex says the system is 20% more efficient than mechanical all-wheel drive technology.
Haldex's system comprises a balance shaft that is connected to a differential. A motor is then connected to the balance shaft creating a torque vectoring function.
Daniel Herven, Haldex vehicle dynamic and control software manager, said: “The main benefit with this concept is that the rotational speed of the balance shaft can be kept low and is not connected to the speed of the vehicle. This means a small electrical torque vectoring motor can operate independently of vehicle speed.”
Haldex has supplied hydraulic all-wheel drive systems for combustion engine vehicles as varied as high performance sports cars and C-segment SUVs.
But as OEMs become more focused on vehicle efficiency the company has had to develop systems which work with a variety of powertrains.
Haldex originally tested the design last year in a Saab 9-3 electric concept vehicle, but the supplier will now use a more powerful version of the technology in a plug-in hybrid due to be tested at the end of this year.
The original design used a 4.3kW torque vectoring motor which allowed up to 500Nm of torque to be used for vectoring, but this wasn’t seen as sufficient, and the new system will allow up to 1,000Nm of torque to be used. Traction torque has also been increased from 950Nm to 2,500Nm.
