Fuel efficiency

[SEMA]

Hello all,

I am a senior in mechanical engineering at the University of Houston and I am on a team that is designing and building a car for the Shell Eco-Marathon. The purpose of this competition is to build a car that gets the best fuel economy.

I am posting today to pick anyone's brain that is familiar with adding a CVT to a go kart. The car we are building is basically a fancy go kart. Off the shelf components are fine for us to use, but we do have to justify why we picked such components in our reports and presentations.

Here are some options we are considering:
-Off the shelf torque converters from Northern Tool
-Nuvinci CVP
-Hydrostatic CVT

The Nuvinci transmission is what I am really curious about. Their website has a lot of great marketing information, but not much in the way of making a selection. And I have not been successful in contacting them via phone or email.

Here is what I have to work with so far:
-600lb max load (car+driver)
-16"-22" wheel+tire diameter
-Yanmar L40AE 4.2HP diesel engine
(We are going to be running Gas-To-Liquid or GTL fuel in our engine. This is liquid fuel made using natural gas via the Fischer-Tropsch process.)

Neither myself nor my teammates have ever been involved in such a process, any suggestions or a direction to go in would be much appreciated.

Cheers!

 

[itsid]

I heard a lot of bad things about the Nuvinci Hub,
so for the eco marathon I'd say it's not going to be reliable enough.
I never tested it though, all I know about it is basically second hand, but what I've heard (all pre N360!) doesn't sound too good.
So be aware since that is an expensive hub.
And I doubt it will withstand the torque of any combustion engine.

Maybe a lestran IVT is a nice transmission for the task, it looks quite small and to some degree lightweight.
http://lestranivt.com
maybe you can talk them into a free prototype for the eco marathon


since this is about fuel efficiency, it'll be quite a task, right.
what's the current record? 3700km/l (8700mpg) or something,

Anyways, I'm very interested,
please keep us posted.

'sid

 

[SEMA]

Thanks sid,

I don't know a whole lot about the Nuvinci but thanks for the heads up about durability. I will also definitely check out the Lestran IVT.

There are 3 Eco-marathons. we will be competing in the Shelll Eco-Marathon Americas; this is where my SEMA name came from.

There are two main categories in this competition: prototype and urban concept. They further break down into gasoline, diesel, electric, hydrogen fuel cell, and solar. We are doing the Urban Concept alternative fuels (new addition for 2014 SEMA) category.
The prototypes are a lot lighter and get the better mileage while the urban concepts have stricter rules and requirements thus making the car weigh a lot more.

The current record holder for the Urban Concept diesel engine is about 120mpg (51km/L). The mileage is a lot higher in the Europe and Asia marathons than the Americas. One reason for this is that the Americas race is held on actual city streets in downtown Houston, TX while Asia and Europe are held on smooth race tracks.

We are aiming for about 120mpg. The GTL fuel is supposed to be just as good as regular diesel, but we will see how well it does. GTL is apparently already being used over in Europe. I see you're located in Germany, do you know much about it?

 

[itsid]

Thanks sid,

I don't know a whole lot about the Nuvinci but thanks for the heads up about durability. I will also definitely check out the Lestran IVT.

just make sure that you get to test it thoroughly (free of charge ),
It'd be a shame if it fails just on the track and you actually paid ~900 bucks

There are 3 Eco-marathons. we will be competing in the Shelll Eco-Marathon Americas; this is where my SEMA name came from.

There are two main categories in this competition: prototype and urban concept. They further break down into gasoline, diesel, electric, hydrogen fuel cell, and solar. We are doing the Urban Concept alternative fuels (new addition for 2014 SEMA) category.
The prototypes are a lot lighter and get the better mileage while the urban concepts have stricter rules and requirements thus making the car weigh a lot more.

The current record holder for the Urban Concept diesel engine is about 120mpg (51km/L). The mileage is a lot higher in the Europe and Asia marathons than the Americas. One reason for this is that the Americas race is held on actual city streets in downtown Houston, TX while Asia and Europe are held on smooth race tracks.

I know there are many different categories, and locations (well three america, europe, asia)
I try to follow that 'competition' on the shell website, since it's unfortunately not part of any TV news or report.
But the mileage makes me wonder...
that's a huuuge difference, the current german held record for urban concept diesel is 315,4 km/l (741mpg)
And a closed track is a closed track, if it's downtown houston or a race track, I see not much of a difference.

We are aiming for about 120mpg. The GTL fuel is supposed to be just as good as regular diesel, but we will see how well it does. GTL is apparently already being used over in Europe. I see you're located in Germany, do you know much about it?

I only heard about it's existence;
so no I have no idea other than a very raw idea what it is.
I know no gas station that actually sells it.

'sid

 

[SEMA]

Thank you sid.

There probably is a lot more to why the Americas competition mileage is so much lower. The GTL fuel is a pretty neat concept that is gaining in popularity as far as I can tell; Shell is actually developing a plant to produce it in Louisiana.

 

[itsid]

I read a few lines on the shell homepage about GTL;
and yes that sounds promising, especially the "drop in replacement" for any diesel currently available;
hopefully there is no hidden poison (hidden as in "yet no need to test for") that will only make things worse...
we'll hopefully see.

'sid