e-Powertrain Design

An electric motor can meet its rated torque, efficiency and power targets and still create a vehicle-level NVH problem. One common cause is torque ripple, the periodic variation in motor torque produced during rotation. At certain operating speeds, these torque fluctuations can excite the rotor, shafts, gears, bearings or motor…

Packaging an electric powertrain is often treated as a dimensional exercise. The motor, inverter, reduction gearbox, cooling system and supporting components need to fit within a defined vehicle envelope. But a package that fits on CAD can still create engineering problems once the powertrain is operating. Changing component positions or…

Higher motor speeds help electric powertrains achieve greater power density, but they also place greater demands on the bearings supporting the rotor. Speed, load, temperature and lubrication conditions can interact in ways that are easy to underestimate during early design. A bearing that meets its calculated static or basic fatigue…

Electric vehicle drivetrains are placing new demands on reduction gearboxes. Higher motor speeds, rapid torque changes, tighter packaging and strict NVH requirements are pushing gearbox design beyond the conditions traditionally seen in many conventional powertrains. The reduction gearbox may look mechanically simple compared with a complete transmission, but it has…