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RE: Where can you use the Volt?
By corduroygt on 12/1/2009 10:55:49 AM , Rating: 1
Perhaps next time you learn to read properly before you post useless facts like an electric motor being more efficient than a gas engine which everyone knows.

My post says a mechanical TRANSMISSION (a.k.a. a bunch of gears) is more efficient than a generator+motor combo. BOTH are connected to a gas engine in the case of Prius vs. Volt. I never compared an ICE to an electric motor, which we all know is more efficient.

RE: Where can you use the Volt?
By eddieroolz on 12/1/2009 3:48:54 PM , Rating: 3
First, I'd like to correct your assertion that I went offtopic.

The best GM cars are LSx powered, period.

That was your statement. Pretty irrelevant, but it was mentioned. So I'm not entirely at fault for going off-topic here.

In my defence: My reason in bringing up the comparison of Internal Combustion vs. Electric motor was not just to screw around with others. It had everything to do with the comparison of the overall efficiencies of two said vehicle types.

Consider this: Say an electric motor is 70% efficient, and internal combustion is 25% (real value for internal combustion is <20% as you know). If you were to compare the overall efficiency of the vehicle, the "bottleneck" here is the internal combustion engine - it is ~45% less efficient than the motor. Hence, even if a motor/generator combo was 10, even 15% less efficient than a simple transmission, the <25% efficiency of the engine should ultimately prove to be the biggest source of inefficiency, outclassing every other component.

In fact, I'm sure you'll agree that most cars out there - even the LSx powered ones - have an efficiency of <25% simply because it's limited by the inherently inefficient nature of the ICE. On the other hand, electric cars like the Volt can achieve perhaps double the efficiency of a traditional vehicle thanks to its motor-assisted drivetrain.


At low or mixed speeds this could result in ~50% increase in overall efficiency (19% vs 29%).

Now I do realize that a mechanical transmission is ~98% efficient according to the source, and the motor/engine combination. So in that aspect, you do have a point.

