Re: The Electric Car

On Tue, 31 Jul 2007 08:14:21 -0700, John Larkin
<jjlarkin@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:

On Tue, 31 Jul 2007 14:37:31 +0000, Guy Macon
<http://www.guymacon.com/> wrote:




Jim Thompson wrote:

I don't ever recall saying "more-efficient-at-higher-speed".

But I guess it WOULD depend on your definition. The engine is
optimized right around 3000RPM (85MPH), but external drag is higher.

Assuming that "optimized" means maximum efficiency as opposed
to maximum power or torque, wouldn't it be more efficient at
3000 RPM in first gear?

Part of me thinks about the far lower drag and says that it
would. Part of me thinks about those pistons moving up and
down more times per mile and sucking in about the same amount
of fuel per cycle and says that it wouldn't. Maybe it needs
an engine sized for 3000 RPM in first gear to make it work?

Also, I can't prove it, but I suspect that hard accelerating
to some speed (don't know how fast) and then shutting down
the engine and coasting down, then repeating, gives the
maximum fuel economy.


Interesting curve:

http://www.fueleconomy.gov/feg/driveHabits.shtml

And it is reasonable to also factor in the value of your time.


John


"Remove excess weight"... don't give a leftist weenie a ride ;-)

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

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Relevant Pages

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