Post your car! (Part Deux)

[Teranfirbt]

There's also the fact that gasoline tech can only go so far.. In the end, there has to be enough fuel going into the cylinders to not ruin everything...

[adciv]

Hey, if a bunch of students can get over 1,000 MPGs...

[Deacon]

In what? Show us.

[Dreamer]

If someone does not explain soon, my head will explode from the sheer economy of it all.

I understand that these are not practical vehicles. they're purpose driven, made strictly for a mpg challenge. But they don't run on anything not already used.

So I understand this isn't the car that I'm going to pack the kids into for a trip to Maine. But still... if some children can make a car that gets over 10,000mpg... Can't we at least have a minivan that gets 50?

What am I missing...

L-i-n-k

[BigGunn]

are-there-enough-hyphens-in-that-url-or-what

[Dreamer]

fixxored

[Infin8Cyn]

Since there are no tech mentions on that page I can only assume some of the methods are things like regenerative electric engines w/gas starts, one wheel drive (with a steep gear ratio on starting), Aerodynamics, etc.etc.

None of those vehicles are suitable for less than ideal circumstances. None would do well in mud, or the hills of San Fran. and so on.

[Deacon]

I understand that these are not practical vehicles. they're purpose driven, made strictly for a mpg challenge. But they don't run on anything not already used.

It's NOT getting over 10,000 miles per gallon of gas. And it doesn't talk about how expensive it was to make and the kind of exotic materials from which it's made, etc. Those are incredibly light-weight, single-person vehicles in which comfort, practicality, and feasibility on public roads are not considerations.

Can't we at least have a minivan that gets 50?

The science of fuel efficiency is pretty simple: reduce the amount of energy it takes to get you from point A to point B. It will always take some energy to do so and more energy to do it in less time. If you've got a few hours, you can make it half a mile down the road with very little energy expended. If possible, you should also increase the efficiency with which that conversion of energy takes place. The former is the primary source of the high mileage you see in those experimental, purpose-built vehicles. The latter is very tricky.

How do you reduce the amount of energy it takes to get you from one place to the other?

The first culprit is weight. Due to inertia, you use the most energy when accelerating (as compared to maintaining a steady pace). Reduce the weight, and increase the efficiency tremendously. Notice how those vehicles were generally made with exotic, ultra-light materials?

The second culprit is wind resistance. It takes energy to push the air out of the way so you can be where it just was. The lower the frontal area, the less amount of air you have to push out of the way. And once you've pushed it out of the way, it's still got to go over and around the rest of the car. The lower the drag coefficient, the easier the air slips around the car, the less energy it takes.

The third culprit is rolling resistance. Honestly, it's the runt of the group, falling much farther behind the others. The more contact area the tires have with the pavement, the more energy it takes to overcome that friction. That's why racing bicycles have those tiny/skinny tires and why you see the same thing being done on those special vehicles in the article. It would be best to eliminate contact with the ground altogether, but the only way to do that currently seems to be increasing speed so that wings take you into flight, and that's got its own set of efficiency and practicality issues (including the fact that the amount of energy it takes to go faster at the same altitude increases exponentially).

You want a minivan that gets 50 mpg on existing production automobile technology? You're going to have to start with a diesel, the weaker the better. Then you're going to have to shave down the shape to reduce frontal area and drag. Then you're going to have to drive it like there was a fragile egg under the accelerator. On the highway, it's certainly possible.

[adciv]

There is, essentially, a list of reasons why vehicles do not get as good of a mileage as they could:
Environmental Regulation
Safety
People want to have other stuff in the car
Top Speed of at least 65mph
Cost

What else am I missing?

One thing I picked up from a Chevy article is that it takes about 200 watt-hours to go 1 mile with an aerodynamic sedan.
Volt gets 40 miles off of 8kwh, 1 mile=200 watt-hours. Aerodynamics is a key part of this.

[fakeblue]

There is, essentially, a list of reasons why vehicles do not get as good of a mileage as they could:
Environmental Regulation
Safety
People want to have other stuff in the car
Top Speed of at least 65mph
Cost

What else am I missing?

One thing I picked up from a Chevy article is that it takes about 200 watt-hours to go 1 mile with an aerodynamic sedan.
Volt gets 40 miles off of 8kwh, 1 mile=200 watt-hours. Aerodynamics is a key part of this.

talking about environmental, I just heard they made an electric engine car reach 100 miles/hour. I wonder if it is hard to start though

[adciv]

That's slow. The record is a specially made car that could reach a few hundred. Wish I could find the link. The tesla roadster can reach 130.

[Lord_Vadus]

Well, as for the nature of this thread, I just wanted to share the pictures of my finished car, now that I'm done with everything that I was doing/fixing with the exception of a performance upgrade to be completed sometime this winter. It's actually my second of these things and if I lose my hair or it turns gray before its time, then this'll be the cause.

My Car

[JeppZer]

And surprise, I could hear Greg go DING! and start drooling infront of his computer, all the way over here.

[Deacon]

Very nice, sir, though I must admit I prefer the black interior to the gray.

[Davinicus]

This is my 1968 Mustang Fastback
You can also see it on youtube
http://www.youtube.com/watch?v=aOGl9ZsmeeI