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I agree with niccolo. It’s very important to distinguish between the Gen 1 and the Gen 2 Volts. I say this in part because your opening paragraph on How It Works is simply wrong. In a Gen 2 Volt, the gasoline engine CAN power the car’s drivetrain directly by itself. That’s a significant difference between the generations - when the battery is depleted, the Gen 1 continues to be propelled by its electric motor, using battery power for acceleration and generator output for cruising, and the Gen 2 becomes a gas hybrid car using an automobile engine for propulsion.
 

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Well, gen1 has both serial and parallel modes once battery is depleted. Parallel (power split) is Prius-like in operation and does result in some engine torque going to the wheels (just less than gen2 can do).
I agree the Gen 1 Volt has serial and parallel modes when the car is in Charge Sustaining Mode (in Hold or Mountain Mode or fully depleted battery) but my understanding is the parallel mode is engaged to improve efficiency (i.e., better "gas mileage"). Power split configuration provides no performance improvement. If you could flip a switch to prevent the system from using 2-motor configuration, you could drive a Gen 1 Volt hundreds of non-stop "electric" miles before the generator ran out of fuel. When you are extending the range at highway speeds in a Gen 2 Volt, you are using an automobile engine as the primary, if not sole, source of propulsion.

My point is that there is a significant difference between the Gen 1 and Gen 2 Volts. The Gen 1 Volt can obtain full performance using only the larger electric motor MGB, which makes it possible to "extend the range" using electric propulsion only (with fuel provided by the battery and the generator output). The Gen 2 Volt is engineered to blend the operation of the 2 electric motors in Electric Mode, and thus when the range is being extended, the system uses the ICE to fill the role of the second motor, adding an automobile engine component to the propulsion configuration. The Gen 1 Volt uses the battery as the source of the fuel that enables the motor to accelerate the car when the range is being extended. The Gen 2 Volt uses the gas tank as the source of the fuel that enables the ICE to accelerate the car when the range is being extended.
 
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