Supermileage Vehicle

[rcman50166]

Anyone here know of any small engine computers?

I do! After a bit of research, and I do mean quite a bit, it seems my team has found a small engine EFI system. I have to call but it seems like it may fit our needs. Your thoughts?

[rcman50166]

Hello gentlemen, I thought I might give you all an update.





This is the bottom half of the new carbon fiber unibody 8) . It was manufactured and donated by Vespoli. The construction and labor costs will ultimately add up to $35,000 for the shell.



Our driver... I'll just leave it there...



This is me in the shell. It is part of a "load test". The bottom half (which is shown) can support at least 200 lbs by itself. It weighs 9.5 lbs. It'll be able to hold even more when the top is added.



This is the progress on the drive train. There is no chain or intermediate shaft yet but you can trace how torque will transfer.



Some "reconnaissance"



Currently designing steering system. More updates later this week.

[D_Hall]

Serious question: Why the battery? Or at least, why such a large battery?

Another question: How are you handling air flow around the engine? It's air cooled, if it doesn't have air flow....

(Other than that, looks great!)

[Technician1002]

@ D_Hall.. I'll pretend to know some of this. If you bun less fuel you generate less heat. That is the answer to the cooling. The battery is to drive all the required electronics. For aerodynamics, there are no projecting rear view mirrors etc. The battery powers the LCD display and rear viewing and possibly front viewing cameras as well as brake lights etc.

It's my best guess from working with some of this before. My Prius when used as an electrical generator (running all weekend) will fill the muffler up with water. It dumps out lots of condensed water when it is moved for the first time. It generates so little heat when it is off for 1/2 hour and runs for 5 minutes to top the battery and the cycle repeats all weekend.

The engine in the super milage vehicle may get a 12 volt muffin fan. No need to burn gas for the engine driven cooling fan to run all the time.

I am going to study the engine module before sharing an opinion. At first glance it looks like it is designed for larger engines. 10 HP and larger.

[rcman50166]

Hey guys I thought I'd do an update. Our car is coming along nicely. We are less that 2 weeks from scheduled completion. Since my last post we have finished the steering, finished the engine and drive train and mounted the entire thing together.

To answer a few questions: The battery size did not originally have to be that large, however we need the weight now. The tilt test requires that we tilt the car 20 degrees to the "driver" side. We had to shift the centroid so much that we had to place the battery on the "passenger" side of the engine. All of our electronics and even engine have been shifted to that side. Now our car sits flat on the ground ready to tip to the "passenger" side. And for out maximum angle that we can tilt before tipping: 20.5 degrees. We are cutting everything very close.

Engine cooling = none. In fact we are insulating it to keep it hot. The car will only be one for 10-20 seconds at a time. We then will coast up to a minute or so. During that period the engine needs to stay at operating temperature so that when we start the engine back up, it's warm and ready to run.

Now for some pictures:





We should get the top half of the body today. We are currently tuning the engine and wiring up the electronic throttling system. We are still waiting for wheel fairings to cover the wheels aerodynamically. We are in the process of making the windshield. We have a presentation of the vehicle on the 4th. We are cutting it close. Wish us luck!

[Big-E]

Honestly, it doesn't look much bigger than the two stroke motors I put on bicycles, probably gets similar mileage too (I get about 150 MPG, without spending an arm and a leg, and it's running a carburetor) I get better mileage when I pedal the bike too.

Which brings me to my next point: When I posted on in the Non Spudgun Related Discussion area about my bike, I got about a page worth of comments; attach some academia to essentially the same thing, and you get a 5 page discussion. Hypocrisy at it's finest... lol.

Just giving you a hard time, man; It seriously looks like a neat little vehicle. In all honestly, it looks like a fun project; good luck to you and your team!

BTW, for those who care, I just tuned up the bike and have taken it out for a few rides for the first time since last fall; still runs and rides great.

My old thread, if you want to look at it...
http://www.spudfiles.com/forums/why-i-h ... 18867.html

[Technician1002]

May I recommend an engine shroud to hold the heat with a thermostatic fan? Underestimating cooling requirements may lead to overheating. It is looking good. Keep up the good work.

[Big-E]

Actually, I'd be more concerned with the duty cycle than overheating; it'll beat the hell out of the cylinder wall with all the starting and stopping and short run times... If you need to cool it, I'd run copper heat pipes from the fins on the cylinder head to just outside the skin of the vehicle; that would probably cool it enough for how they're using it.

What carb are you guys running, and how is it jetted? What fuel are you using? run rich if you want to run cool, lean engines are more efficient, but run way hotter. It's all fun and games until you burn a hole in a piston or crack a cylinder.

(EDIT) ah, It seems as though you went the EFI route instead. or is it TBI, hard to tell. Looks like you have a reed on the intake side too: My bad...

[rcman50166]

What carb are you guys running, and how is it jetted? What fuel are you using? run rich if you want to run cool, lean engines are more efficient, but run way hotter. It's all fun and games until you burn a hole in a piston or crack a cylinder.

We are using a Mikuni VM-16 carburetor. It is currently jetted for gasoline, however we are getting new jets. We calculated the AFR of Iso-octane to be 15.175 to 1. I thought that would be nice to post here because it doesn't appear to be anywhere else on the internet.

[boyntonstu]

If you watch the clip, you will see several rather amazing claims:
- The car has a very small engine – a 1.3 liter, 112 HP diesel
- The car only weighs 1,455 pounds
- But the top speed is 155 MPH
- Most amazingly: in the 24 hour endurance race, its average speed was 140 MPH and the fuel economy was 113 MPG.

[youtube][/youtube]

[Big-E]

We are using a Mikuni VM-16 carburetor. It is currently jetted for gasoline, however we are getting new jets. We calculated the AFR of Iso-octane to be 15.175 to 1. I thought that would be nice to post here because it doesn't appear to be anywhere else on the internet.

Wow, that sure is running lean! I guess if you're shooting for economy, you're going the correct route, but you're riding the razor's edge in terms of reliability. In the world of performance tuning, we try to keep it around 12:1 to keep detonation at bay.

From my searching over the years, I've heard ratios around 14:1 are optimal for fuel economy, so I'd say your numbers are pretty much on target. Seeing that you're running a briggs (I know them well) you can put them through a lot of punishment. In my opinion, I think you're design will hold up just fine. I read the link you posted, looks like a nice carb, and mikuni carbs are very nice to tune with in general. Just remember, in the manual, it even says that if temperature isn't controlled properly, you should richen the mixture a little to prevent the engine from seizing. I realize this probably isn't an option, but you may want to have a engine temp gauge to monitor it, just to be sure.

Definitely let everyone know how you did at the event. If there are any mechanical issues, be sure to let us know what went wrong. I'm definitely going to be watching this thread

[deathbyDWV]

Looks like it's going good. Good luck.

I saw this and thought you might be interested...
http://www.gizmag.com/student-built-car-2487-mpg/14707/

[rcman50166]

Looks like it's going good. Good luck.

I saw this and thought you might be interested...
http://www.gizmag.com/student-built-car-2487-mpg/14707/

Laval...Grrr.. They :sign10: all over the competition every year. They have seen over 3000 mpg before. They are essentially the team to beat. However rumors through the grape vine say that a team will be there with a car with an economy of 4200 mpg. Our school will get there... some day :thumbleft:

[jackssmirkingrevenge]

They :sign10: all over the competition every year.

Thank you for the visual aid

[Labtecpower]

Belts have a higher efficiency compared to chains. Chains have an efficiency
up to 94%, while belts are as efficient as 99%. Definately something to
keep in mind in my opinion.