Originally Posted by
Doug Garson
Can anyone explain the physics behind the 75 mph Opel hybrid? You are still using a gasoline engine as the only source of power. Is there that much efficiency gain from running the gas engine at fixed (assume most efficient ) rpm plus regenerative braking? Or do they not include gas burned to charge the batteries when the car isn't moving?
Is that mph or mpg? Seems like 75mph wouldn't be hard.
[I went and looked at the original post. It's mpg. I doubt if they honestly get 75mpg out of that. They have a 100 amp 12 volt generator. That's 1200VA (or Watts). A perfect HP is about 750 watts so that system can produce about 1.6 HP if there were no losses. A more honest HP is about 1,000 watts so that system would produce just a bit more than 1HP. Once you depleted the batteries you aren't going to be traveling very fast.]
It's probably even worse because there are losses in the electric motor. The mechanical power out will be lucky to get 1HP.
It looks like the batteries are connected in series so maybe the generator is 48 volts. That would give them 4800VA, which would give them 6.4 perfect HP or more likely about 5HP. But the gasoline motor is only 5HP so with losses, the output from the generator is probably more like 4HP. After going through the cables and the losses in the motor, you'd be lucky to get 3HP to the wheels.
When they publish something like that article on the Opel, you wonder if anyone (writer or editor) can do just a bit of mathematics when evaluating the claims before publishing it.
Mike
Last edited by Mike Henderson; 11-05-2020 at 1:18 PM.
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