[NeilBlanchard]

EV WORLD CURRENTS: Tempest in a Teapot

As the paper describes it, the Volt has four driving modes: single motor EV, two motor EV, single motor extended-range, two motor extended range combined. The single e-motor (EM1) is used to launch the vehicle and operate at it lower speeds. It can develop 111kW of power, giving the car brisk acceleration. For high-speed EV-only travel, the electric generator that is attached to the IC engine, converts into an electric motor (EM2), providing additional torque to propel the vehicle using battery power only.

It is only when the battery is depleted below 45% state-of-charge (SOC), that the IC engine fires up and the second electric motor (EM2) reverts back into a generator, producing enough electric power to propel the car another 300+ miles. State's GM's technical brief:

Regardless of which drive mode is used, the Volt is always propelled with electric power delivered by the traction motor. The engine cannot propel the Volt unless the traction motor is also running. In order for a planetary gear-set to transmit torque, at least one of the three main elements (ring gear, sun gear, or planet carrier) must be able to be locked or held. Since there is no clutch to lock the sun gear, the traction motor must be used to provide the reaction torque needed for propulsion.

According to GM, "this unique propulsion architecture allows the Volt to achieve 10-15 percent better efficiency at highway speeds than would have been possible by using only the single traction motor."

(Emphasis is mine.)

Using a very complex system of planetary ring and sun gears, plus three clutches and two electric motors

(Emphasis is mine.)

So, the Volt could be a series hybrid without a battery at all. It is a series/parallel/split hybrid and it does not need a battery to be any of those.

Is it a car with a hybrid drivetrain, or isn't it? Does it need to be a plug-in to be a hybrid, or not?