OEM&Lieferant Ausgabe 1/2020

90 New Products and Markets High Level Efficiency: Integrated GenVI AWD-Actuators BorgWarner supplies automakers with efficient AWD (All-Wheel-Drive) Technologies By Christian Månsson, Development Engineer, Mechatronics, BorgWarner PowerDrive Systems, Måns Ranåker, Director Driveline Engineering, BorgWarner PowerDrive Systems and Per Söderberg, Development Engineer, Motor Design, BorgWarner PowerDrive Systems When talking about the development of newAWD technologies, fuel-efficiency is the buzzword. Therefore, design- ing its sixth generation of actuators for AWD systems BorgWarner has focused on improving efficiency, durability, weight and packaging. OEMs benefit from high volume production and the minimum of new development required. For 20 years, the company has been supplying the automotive industry with AWD solutions. Today it produces more than 1.5 million GenV couplings for global manufacturers and has started serial production of GenVI. As with the generation before, development is based on thorough in-house testing and specific cus- tomer requirements. The centrepiece of this latest generation of actuators is the patented centrifugally controlled piston pump, which is capable of creating and controlling the pressure in the system. The six-piston axial pump manages to produce high pressure levels with an elevated standard of efficiency. With its centrifugal control valves, the pump creates a connection between the rotating speed of the motor and the pressure within the system. As speed is the set-point for this kind of motor, the system, therefore, is verywell suited to being driven by a Brushless DC motor (BLDC). The advantages of this design are high pressure accuracy and a very good response time for any setpoint changes requested. Design of the AWD actuator The sixth generation actu- ator consists of the follow- ing, optimized components: a BLCD-motor (designed and manufactured in-house) that offers improved durability, reduced size and better ther- mal capability; an integrated Electronic Control Unit (ECU) for reduced costs, improved packaging and robust electro- magnetic compatibility. Aligned ECU and stator diametres allow for a robust assembly process and minimized product cost. A dry stator and the ECU prevent any oil compatibility issues be- tween oil, electronics hardware and interconnects. A wet rotor eliminates the dynamic radial seal between the pump hous- ing and the motor shaft. Sensor-less controls are utilized but the design allows for a sensor to be integrated if required. Optimized weight and packaging size The GenVI is able to further reduce the weight of the system by more than 15 per cent for a part time AWD coupling. The integration of an ECU in combination with a smaller e-ma- chine reduced the actuator size significantly. Together with a flexible hydraulic actuator, this results in optimized packaging giving OEMs the opportunity to optimize their packaging as well. Improved accuracy and response time Using a BLCD motor with speed control im- proves the pressure accuracy of the system. At normal operating temperatures the motor controller increases flow control of the pump and improves the time the entire systemneeds to reach altered setpoints. System durability and eco mode While a brush system DC motor has a shorter operational life due to the wear of the brushes Image/Graphics: © BorgWarner Cross section of piston drum Cross section of the BorgWarner GenVI hydraulic actuator with integrated ECU