Bosch has developed a rigid e-axle that integrates the electric motor and transmission for commercial vehicles weighing 18 to 49 metric tons. That range runs from rigid distribution trucks up to tractor-trailer combinations.
A rigid e-axle carries the drive unit at the axle itself, so torque reaches the wheels without a propshaft running back from a centrally mounted motor and gearbox. Bosch says the arrangement cuts vehicle weight and runs more efficiently than a conventional electric center drive. The two layouts compete in heavy trucks, and each brings trade-offs in packaging, driveline losses and how much of an existing chassis a manufacturer can carry over.
Paired with silicon carbide inverters, which Bosch rates at up to 99% efficiency, the axle lowers operating costs in freight transport, according to the company. Silicon carbide MOSFETs switch with lower losses than the silicon IGBTs they replace, so less of the battery’s energy is dissipated as heat on the way to the motor.
A high-voltage blower module for 800 V architectures was developed specifically for electric commercial vehicles and off-highway machines. Higher bus voltages move a given amount of power at lower current, which keeps cable and connector sizes down in the high-voltage auxiliary circuits. Cooling fans in an electric truck draw from the same pack that moves the vehicle, so fan power is a parasitic load on range in a way it never was on a diesel. The module cools key vehicle components on demand rather than running continuously, which Bosch says reduces energy consumption and increases range.
Source: Bosch
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