There is nothing that keeps hybrids from scaling. As I noted, trains have been using them for a century or so. And Porsche's failed prototype for the German Tiger tank was similar. The hull was later repurposed for the Elefant tank destroyer, so it did make it to the battlefield. Now a big motivating factor in that usage is the high torque at zero rpm. Which greatly reduces the need or complexity for the transmission.
BMW's i3 had a range extender option, so I am not sure what the issue they had with other use cases. But the i3 was intended to be BEV and a technology demonstrator and not really aimed at BMW's core market.
My use of "optimal" was more in the sense of efficiency. IC engines are at their most efficient when running in a rather narrow rpm band. Which means they are best at running a generator. A constant velocity transmission can somewhat compensate for that or a large number of gears, but they introduces large losses due to friction. Not to mention, cost and complexity.
There are several ways to make a hybrid. You have a Prius, which incorporates the electric motors to the transmission. I admit, I am not a fan of this approach. But Toyota took the understandable route of minimizing the changes to their manufacturing flow. From a manufacturing point of view and glossing over lots, they just replaced the transmission with a bulkier unit.
The Corvette E-Ray just slaps a motor in the front for those wheels, making it an AWD and called it a day.
For Formula F1, they looked at what Toyota did, said "hold my beer" and dialed it to 11. Sucking in the engine into the transmission/electric motor mix and squeezing 1k horses out of a 1.6 liter ICE.
As you might have guessed, I favor the ICE and generator combination, making a power unit, preferably a module. So it is essentially a noisy fuel cell and gives a lot of flexibility with fewer parts. It lets the designers change the ratio of battery to power unit to meet various use cases. |
