|The Optima Bus Opus diesel-electric series hybrid|
The Opus Hybrid is based on an ISE-Siemens series hybrid powertrain, and is projected to reduce fuel consumption (and associated emissions) between 20% to 40%, depending upon the route and driving patterns.
A 5.9-liter, six-cylinder Cummins ISB produces 260hp and drives the generator that powers the twin 85kW drive motors, which produce 220 Nm torque, 450 Nm peak.
The ISE drive uses twin ultracapacitor packs from Maxwell for energy storage, each with a nominal voltage of 360 VDC and peak voltage of 403 VDC. Total energy stored is 0.325 kWh, 0.407 kWh maximum. Regenerative braking recharges the ultracapacitors.