The Hybrid Electric Vehicle (HEV) is becoming a sustainable vehicle architecture with the US government pouring 14.4 billion[1]into stimulus projects that support drivetrains of new vehicles that are hybrid or Battery Powered (BEV). Both the series hybrid and BEV have 100% of propulsion energy coming from electricity. The series hybrid uses an Internal Combustion Engine (ICE) to power a generator that produces electricity. The parallel hybrid powers the vehicle by a mechanical combination of electric motors and ICE. In all cases, the drivetrain needs an electric motor, a traction battery and an auxiliary method of obtaining electricity. These Auxiliary Power Units (APU) are typically a downsized, highly efficient ICE or fuel cells for a zero emissions alternative. Horiba’s Virtual Engine (VE) and Virtual Battery (VB) are HIL[2]products that allow electric motor based drivetrain development without waiting for the new battery pack and ICE to become available. Relevant product features for HEV development are discussed in terms of form, function, and verification with data.