Electric cars, unclean at any speed

[redpoint5]

Originally Posted by UFO

.....^
----l

Now THERE is an example of an "unclean" electric vehicle.

Just to play Devil's Advocate; perhaps the vehicle was not equipped with AC, and the owner happened to have a generator and wall AC already.

How much would one have to run the generator (and suffer aero inefficiencies) until they expend more resources than it would take to build and equip the vehicle with an AC?

Obviously this is an extreme engineering oddity, but I run 2 small AC window units in my 2100 sq/ft home. For my comfort level, they are barely adequate. But then again, I only feel the need to run them 20 days out of the year. Since they were given to me, it's much more efficient than building a whole house cooling system that wouldn't get a lot of use.

Again, not really arguing the practicality of using a generator and wall unit in a vehicle.

[NeilBlanchard]

From the X-Prize Knockout Round:

The average of the 12 vehicles using electric drive MPGe (I'm including the FVT in this [which is a serial hybrid]) was 134.7MPGe
The average of the 6 hybrids (not including the FVT) was 61.26MPGe (Please note, these are all parallel hybrids?)
The average of the 5 internal combustion drive cars was 82.92MPGe

The internal combustion cars included a diesel, E10, and E85, so MPGe is required to compare them. Here's the spreadsheet used in the X-Prize:

http://www.progressiveautoxprize.org...Calculator.xls

A parallel hybrid has to be switched between electric and ICE power - how and when is this done? If you use up the charge in the battery at the beginning of a long trip (or during during the slower portions), then how do you recharge the battery to drive slowly again at the end of the trip? If you cannot charge the battery (given it is a PARALLEL hybrid!) how do you drive the car slowly, or up hills or into a headwind - or any other time that conditions are less than ideal?

Would you be forced to have a multigear transmission and a larger more powerful engine? If so, then what does that do to the efficiency?

[UFO]

Originally Posted by redpoint5

Just to play Devil's Advocate; perhaps the vehicle was not equipped with AC, and the owner happened to have a generator and wall AC already.

How much would one have to run the generator (and suffer aero inefficiencies) until they expend more resources than it would take to build and equip the vehicle with an AC?

Obviously this is an extreme engineering oddity, but I run 2 small AC window units in my 2100 sq/ft home. For my comfort level, they are barely adequate. But then again, I only feel the need to run them 20 days out of the year. Since they were given to me, it's much more efficient than building a whole house cooling system that wouldn't get a lot of use.

Again, not really arguing the practicality of using a generator and wall unit in a vehicle.

Actually, I'm sure that's the case, but I bet the factory AC just failed, and that generator on the trunk and AC in the window was the repair. It's just so ridiculous-looking I had to poke fun.

[P-hack]

Originally Posted by NeilBlanchard

so MPGe is required to compare them.

No, it is still arbitrary to munge electric and fuel use together for a competition, but their individual contributions are not ambiguous, so it makes sense to track it at that level of detail. Just good form.

Originally Posted by NeilBlanchard

Would you be forced to have a multigear transmission

If your range extended trip is all hiway then there is a notable chance that you won't. But you are only dollars away from an optimal low loss transmission.

Originally Posted by NeilBlanchard

and a larger more powerful engine?

It doesn't need a more powerful engine, it need a less powerful one.
1. the conversion losses in series (mostly heat).
2. pusher is redundant. Depending on your range extending needs it doesn't have to push much at all and can be any size, though smaller is towards higher bsfc.

Originally Posted by NeilBlanchard

If so, then what does that do to the efficiency?

How did you turn a higher known peak efficiency across a wide portion of the rpm band into needing a larger engine?

[NeilBlanchard]

If the battery is depleted, and the electric motor cannot be used on slow speeds or up hills to assist, then the ICE that is designed for optimal higher speed cruising at a peak efficiency - would not have enough torque to accelerate from a stop, and/or go up a hill and/or into a headwind without a multigear transmission.

What this means is, a parallel hybrid by definition, would need to be able to move the vehicle with either the ICE or the electric motor - which changes the requirements for the ICE; making it bigger than ideal - which adds to the weight and the complexity of the design. More cooling is required, and the mechanical drivetrain becomes larger.

It also means that the control systems or the driver has to do the mix-and-match of what propulsion is used.

All this is for a "pure" parallel hybrid. Most hybrids today are multi-mode in that they can be serial or parallel or both at the same time.

A "pure" serial hybrid on the other hand, has no need to have a larger than ideal ICE. A serial hybrid is essentially an EV with a genset, so the electric motor is the only one that has to be sized to move the vehicle, and the load on the ICE is known and fixed at all times. The ICE only runs periodically, so the cooling system can be closed off when not in use, and the ICE will warm up more quickly because it is a smaller displacement.

A serial hybrid will not run out of battery charge, so the "rhythm" of the drive and load profile is not dictated by the drivetrain. It is much more flexible, and the design parameters are much more tightly defined.

The FVT eVaro is a serial hybrid and Ken Fry's 'Zing' is a serial hybrid. There are no pure parallel hybrids, as far as I know. The "closest" is the XL1. Most hybrids are mixed mode (Prius, Volt, etc.) and some are so-called mild hybrids, with the electric motor limited to boosting the peak torque.

The XL1 demonstrates the only way I think a parallel hybrid can be done. It can only put energy into the battery with the plug, or with regenerative braking (which is only on the brake pedal, incidentally) and it can do charging only when the driver holds their foot lightly on the accelerator pedal.

[jamesqf]

Discussions of efficiency aside, you all are ignoring the real issues. First, that a pusher or generator on a trailer is not always going to be there when you want it; second, that a pusher trailer is going to terminally screw up handling and lead to many jackknifing accidents. An on-board generator, a la Volt, solves both of these problems.

[P-hack]

trailer is simply an abstraction at this point, so that we don't get into interior space arguments. The generator can be on board as well as the pusher can be on board and coupled to a wheel or two, efficiently. And there are plenty of sway control options and main vehicle affixing options too if it is a trailer of sorts.

[litesong]

Originally Posted by ConnClark

When you consider there are no more rivers that can be dammed.........the fact that wind and solar aren't consistent and cost a lot.......

Since you're a fossil fuel advocate, ya still got to tell the same falsehoods, based on static technological development that fossil fuel boardroom PR denial of 20 years ago, has been pumping ever since.

Ninety five percent of the dams in the country have no hydro-electric generating capability. Studies are being run to see which dams are suitable for electrical generating facilities & thousands of potential mini-hydro electrical facilities are in the works.

Wind turbines are dramatically more efficient than your sick assessments. One technological advancement alone, allowed turbines an increase in 15-20% efficiency. Size by itself, that fossil fuel advocates demean, cause massive & multi-pointed increases in efficiency. Wind turbines & hydro-electric facilities integrate the best of any combined electrical generating facilities.

[mercedes308]

The amount of materials used to make environmentally friendly car, may be more than a conventional car. But lithium from batteries can be recycled, just the same as anything else.
The majority of environmental impact, with cars is when they are been built, not with use. So it's better to modify/clean up an old car than build new to the same standard.
Carbon footprint is also a red herring
in so much as they fail to consider the carbon taken up by the vegetation replaced by the fuel crop, that would not have been released into the atmosphere.
Electric vehicles powered by wind,hydro,solar are the future. And older vehicles modified to run on electric, even better.

[IamIan]

Originally Posted by mercedes308

The amount of materials used to make environmentally friendly car, may be more than a conventional car. But lithium from batteries can be recycled, just the same as anything else.
The majority of environmental impact, with cars is when they are been built, not with use. So it's better to modify/clean up an old car than build new to the same standard.
Carbon footprint is also a red herring
in so much as they fail to consider the carbon taken up by the vegetation replaced by the fuel crop, that would not have been released into the atmosphere.
Electric vehicles powered by wind,hydro,solar are the future. And older vehicles modified to run on electric, even better.

Green = Good

Red = Error

The rest is subjective to a more specific context. True in some cases , not true in others.