Dana investigated electromagnetic torque converters for off-highway drivetrains
Increased environmental awareness and stricter legislation enforce vehicle manufacturers and their suppliers to adopt new technologies and develop more efficient drivetrain solutions, characterized by both a reduced fuel consumption and a lower total cost of ownership. The market segment of off-highway drivetrains is under pressure by hydrostatic transmissions and by electric solutions.
In the ConceptDesign ICON-project, Dana and Flanders Make investigated 3 different Electro Magnetic Torque Converter (EMTC) concepts: Induction Motor (IM) based, Permanent Magnet (PM) based, and Magnetic Gear (MG) based. Detailed electromagnetic simulations revealed that a PM-based EMTC exhibits the best characteristics. It turned out that the EMTC efficiency reaches up to 95% for a large operating region. Moreover, the starting power requirements on the engine are strongly reduced due to the low electrical losses compared to the hydraulic losses in a conventional torque converter (HTC).
Next, a model-based drivetrain optimization framework was set up to determine the best drivetrain properties (e.g. engine power, transmission ratios, power electronics sizes, etc.) and its controls. This was achieved by developing and implementing computational design synthesis methods and tools.
The analysis revealed that the expected EMTC installation cost will be 7 times higher compared to the its HTC equivalent, increasing the entire driveline cost by 50%. However, as shown in Figure 1, due to the better use of the engine and the more efficient torque converter, the operating cost of the hybrid transmission is reduced by 18% w.r.t. HTC over the entire vehicle lifetime (5 years). Since the energy cost is dominant in such applications, the total cost of ownership is estimated to be 9% better compared to the traditional HTC driveline.
The project identified that the best concept for the EMTC is PM based, as well as the best sizing for the device. Next, the concept will be further elaborated in a pre-development with the intent to bring the product to market after further development. The early selection of the best concept from a TCO standpoint allows Dana to shorten the pre-development and development time and to bring a better product more quickly to the market.
Evaluation of off-highway drivetrain concepts including an Electro-Magnetic Torque Converter (EMTC), Hydraulic Torque Converter (HTC), Hydraulic Torque Converter with lock-up clutch (HTC-LUC): Installation cost (left), Energy cost (middle), and Total Cost of Ownership (right) – values w.r.t HTC-installation cost