Building a 100mpg consumer vehicle

[drmiller100]

the only diesel option I considered is an old vw diesel rabbit, non turbo. 60 horsepower or so, FWD, really light.
I might build one of those, or stuff the engine in my car if I can't get to the 75/75 mark with gasoline.

I own a couple of VW pans. I built several cars off fo those. for a variety of reasons I want FWD.

[Diesel_Dave]

So what about the "consumer vehicle" definition? Are you planning on selling this vehicle commercially?

[drmiller100]

A dream would be to sell a few vehicles a year to feed my children.

Realistic? I don't know.

I am building it in case it works - 3 wheelers are motorcycles and don't require crash safety stuff. I am using automotive motors so I can get past the EPA regs.

And I want to make it as "consumer friendly" as reasonable.

My landlord came by yesterday - he said he would want one with an automatic transmission even if he only got 60 or 70 mpg. He spends too much time on the phone to shift gears and survive in traffic.

[Diesel_Dave]

I'm more familiar with large diesel EPA regs, but here's my take:

I don't think using an automotive engine will get you past the EPA regs. I think the regs are based on the year of the vehicle--not the year of the engine. In addition, I believe all passenger vehicles need to be chassis certified (not engine certified)--so the vehicle needs to be certified, not the engine.

That being said, here's 2 ideas for how you might get around the EPA regs if you decide to go commercial:
1) Look into what regs apply to "choppers". I mean, guys make custom motorcyles and trikes and I assume the EPA is okay with that.
2) If you're just selling it in Idaho, for use in Idaho, you might not have to deal with the EPA. This is because, it wouldn't be "interstate commerce", and therefore not under federal jurisdiction. I think I recall hearing about Montana or one of those western states that was using this argument with respect to federal gun laws. They claim is the guns are made in the sate, sold in the state, and marked to not leave the state, then the feds didn't have jurisdiction.

Just be glad you don't live in California!
http://abclocal.go.com/kabc/story?se...ent&id=4977150

[Ryland]

What route are you taking to license and title this vehicle?
My favorite route that works well in my state is hobbyist plates, those are the plates that are used for home built vehicles, but also for hot rods, kit cars or any vehicle that is no longer stock and is over 20 years old, because of that loose and broad definition you can pretty much take any 20+ year old vehicles vin number that you also have a title for and put it on your home built vehicle, if you are building a kit car or home built vehicle then they want records that show that parts you used were not from stolen vehicles and it is supposed to be inspected.

[drmiller100]

I have the titling and licensing figured out. Don't really want any help on that, don't really want any unfounded opinions which start big problems, rumors, and issues.

Suffice it to say I can build my vehicle for my use legally. Someday if I choose to sell one or two I will do it completely legally.

[Ken Fry]

Originally Posted by drmiller100

The Zing is a different approach. I am actually ahead of that project in terms of build and layout. he will have a few surprises, but and I invite the owner/designer of that company to jump onto this thread, and I would be willing to discuss in order to both build a better car.

Hi Doug,

The Zing! is driveable. It has been getting 100 mpg on gas and 10 miles per kilowatt-hour on electricity (which the EPA calls 337 MPGe). I hope others do not think that the Zing! is just an idea. (The Volt, for comparison, gets 37 mpg on gasoline, and less than 3 miles per kilowatt-hour (93 MPGe))

The term "proof-of-concept" prototype may have tripped you up. The concept has been proved -- the car performs as predicted. The Zing! POC is not like a Detroit "concept" car where they are showing off styling and future ideas on a chassis that may not even have an engine.

Your project sounds like it should be fun.

Regards,
Ken

[Ken Fry]

Originally Posted by drmiller100

the only diesel option I considered is an old vw diesel rabbit, non turbo. 60 horsepower or so, FWD, really light.
I might build one of those, or stuff the engine in my car if I can't get to the 75/75 mark with gasoline.

I own a couple of VW pans. I built several cars off fo those. for a variety of reasons I want FWD.

For perspective on engines, chassis, and aero:

Steve Fambro built a gasoline-only Aptera (as one of their numerous prototypes). It had a 660 cc kei car engine. Like all the Apteras, it has excellent aerodynamics and a composite structure. He got 55-60 mpg. The same car with a Civic engine would get about 45-50 mpg.

If you hunt around for the BSFC maps for these engines, you will see that when producing 15-20 hp the 660 is substantially more efficient than the Civic engine at that hp, because it is more heavily loaded.

As a general rule, unless you are planning to create a hybrid, around town mileage will be lower than cruise speed mileage. The Prius is the only car in which both figures are essentially the same.

A good place to start, unless you have unlimited funds, is with the math. You will find that for 100 mpg, your car must need very little HP to go 60 (on the order of 6-8). That means very light weight and excellent aero. Once you have that, then you cannot use a large engine because you also need very low brake specific fuel consumption, which means a highly loaded engine.

Do you have a Cd value for your body, and its frontal area?
Have you calculated the HP requirement at 60?
If you have the data I can run a spreadsheet for you.

Regards,
Ken

[drmiller100]

60 inches wide front fenders, 2 feet tall.

cockpit is 42 inches tall by 35 inches wide.

The windshield is behind the fenders. Does that mean my frontal area is 10 square feet, or 10 plus 5?

No idea on Cd. .30 should be pretty easy. .20 possible????

Lets guess 1000 pounds.

I've got a few ideas to try to improve efficiency on the engine. lean burn is a no brainer. cam profiles are worth messing with. And i have a couple of other ideas from old school rednecks.

If I get close, but can't get it all the way, I've thought about using V-tec to hold two cylinder's exhaust valves open, and shut off two fuel injectors. Idea would be I would shut off two cylinders and lose the pumping losses at part throttle.

I've got another couple of ideas to minimize pumping losses and relieve the penalties of a large cc engine.

[drmiller100]

Ken, on your car, I tried mocking up seats with true tandem. We really did not like comfort in the back seat, and our criteria is a 45-60 year old lady MUST be comfortable in the back seat. We ended up making the cockpit a bit wider, and it REALLY added to comfort and usability.