Quote:
Originally Posted by PeeBee
I went to test drive a Fisker Karma recently, and despite having the same "all time electrical drive" it has a 2.0T.
The reason behind it is, according to the sales guy, that sufficient electricity needs to be generated to let the car drive the same when the battery eventually goes flat during a long drive...
Kind of like a generator's fuel engine... make it smaller and you'll have less power, the more powerful the fuel engine, the more electricity you get...
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But the difference is, the Karma weighs about 50% more than the Volt and is about twice as powerful. So the demands to keep similar levels of performance are far higher.
Additionally, you don't need the engine to be more powerful than the electric motors with these cars. In fact, on both the Volt and the Karma the gas engine is less powerful than the electric motor(s). The reason is that when driving cruising around, they'll only be using 25-40 hp most of the time. Sure, accelerating will use more but you only need that power briefly. So with the gasoline generator, the idea is for it to produce just enough power to keep the battery charged a little bit (so there is some power on tap for when you want to climb a hill, for example). They size the engine so that it can provide those power levels in a very efficient manner (which is absolutely not wide open throttle at 6500 rpm). Consequently, the Volt could do away with a cylinder (thereby saving weight & cutting down on internal friction) and it would improve efficiency without really harming its overall drivability (since the tiny engine could still deliver twice the power required, if need be). Sure, it might not help things if you ever plan on cruising the Autobahn at over 100 mph ... but at the same time, that would be the Ampera's problem -wouldn't it?