How would you build a car to compete for the X Prize? 4

[EdDanzer]

The rules for the Automotive X Prize (

http://auto.xprize.org/)

will be posted soon.

They think it will take less than 18 month to finance, design, provide a detailed production cost analysis, build and test a 100 mpg 4 passenger car that meets all the safety and emission standards world wide.

How do you think this can be done?

 

[reidh]

I imagine that most competitors will attempt to attain this goal through reduction in weight by using exotic or non-traditional body materials. I don't think the engine technology will be anything radical or groundbreaking. We will just have to wait and see.

Reidh

 

[GregLocock]

Frankly, I wouldn't touch it, unless I had an engine/transmission design that was ready to go, and a body that was nearly there.

In order to meet crash regs you'll need at least three, and up to 50, prototypes.

Tooling for many parts is >6 months.

100 mpg is a nice round number, that's 2.5 litres per 100km, roughly. So if I were to take the best technology around, that gets ~ 70 mpg for a 4 seater... and doesn't meet US crash. If you were lucky you could add 150 kg to meet US crash (which will hit fc) , and then hybridise it, for a 50% improvement in fuel consumption.

Having said that if anybody wants a cynical mechanical engineer to work on concepts, timelines, and analysis, you know where to find me.



Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[MikeHalloran]

"The Automotive X PRIZE will invite teams from around the world to focus on a single goal: design viable, clean and super-efficient cars that people want to buy.

This will be a race for the ages, with major publicity and a big sack of cash waiting for the champion, and perhaps our future hanging in the balance."

Funny.. I thought the market was doing that already.



Mike Halloran
Pembroke Pines, FL, USA

 

[patprimmer]

First of I don't think it can be done in the time frame.

They ask for production costs. Do they have a maximum cost target, as obviously complex design and exotic materials can help.

Are there any performance criteria like acceleration, parking ease, external vision in all directions, cabin temperature, top speed, hill climbing, road holding, ride comfort, cabin space, luggage capacity etc etc etc.

I would think the best design concept would be a long narrow car with the passengers sitting in line slightly skewed so the foot wells extend to beside the seat in front. Head room would be very tight. Large passengers would not fit, the roof would probably be a solar cell.

Regards

eng-tips, by professional engineers for professional engineers
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[EdDanzer]

Here is a link to the first presentation

http://xprize.acrobat.com/p92151066/

Have to go skiing so I will check in later.

 

[tbuelna]

The automakers probably spend a billion dollars and take 3 to 4 years to get a new chassis/engine/transmission to market.

This sounds like typical liberal academic fantasy.

 

[cibachrome]

I suppose its time to introduce the di-lithium crystals (only naturally made), tranparent aluminum, and of course ion drive. We've lost Engineer Scott, but there's probably somebody from Berkley waiting in the wings. Last time this contest had entries at our place, most didn't survive the car wash. Oops...

My guess its a hydrogen fuel-celled electric golf cart sized entry with solid tires, little suspension, and 0 to 60 mph time in the 2 dozen range.

 

[GregLocock]

Draft regs are up at

http://auto.xprize.org/downloads/AXP_Draft_Competition_Guidelines_20070402.pdf

Cheers

Greg Locock

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[WolfHR]

I guess it will be thought of as an abominable idea, but how about 250cc two-stroke engine, with a good rotaty valve (say, variable timing) and CVT? Could that get near the fuel consumption on a light car, with reasonable power output?

 

[GregLocock]

Has to meet emissions. read the rules.

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[WolfHR]

Greg, I think 250cc will meet the emissions even without variable valve timing (but I proposed it to get better fuel consumption/emissions across the whole range of revs)- at least, I think they're still sold in bikes in EU.

 

[EdDanzer]

I doubt any 2 stroke gas engine can meet the required pollution requirements.

The one lacking requirement in the rules is the required production cost.

My interest is the mainstream class vehicle. It seems you need to improve existing car fuel mileage by 3 times, yet maintain the acceleration performance and have a high top speed. The acceleration and top speed will make for design difficulties.
1. Can enough weight and aerodynamic resistance savings make this possible at the required sale price?
2. How many man hours should it take to design the body, frame and suspension?

 

[GregLocock]

1) well, that's just engineering. I can see it happening so long as all the things that are poorly defined in the rules get left out. No crash, no airbags, no durability etc etc.

2) To what standard? Why not just buy an Audi A2 and fit your powertrain to it?



Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[EdDanzer]

The problem I see with using an existing car is getting past the production cost requirement. What car manufacture would quote selling a partially built car for drive train and control retrofit?
Page 10 of the draft rules is about safety and it does specify UNECE or US FMVSS compliance.
I have ask APX for clarification of the target manufacture cost, if there will be extensions if no one qualifies in 2008 and have signed up for the Letter of Intent to find out more and see if there really is people to invest in doing this type of project.
1. In 10,000 per year manufacturing quantities what are some of the more cost effective methods to build the frame and body?
2. Would it be faster and or less expensive to subcontract out the crash analysis, and body CFD?
Estimating what it is going to cost and how long it will take to get to race day seems very difficult.

 

[MikeHalloran]

Ten thousand units a year is a horrible production rate to design for. It's too high for hand- building, and too low to justify serious automation.






Mike Halloran
Pembroke Pines, FL, USA

 

[thundair]

Mike
Production seems impossible to do without body in white technology, from what little I know it would take stampings and robotic welds to accomplish 38 cars a day or is my calculation way off...

Cheers

I don't know anything but the people that do.

 

[MikeHalloran]

I get 50 cars a day for 200 working days, which used to be the standard automotive year, allowing for weekends and shutdowns.

I worked in Ford's axle plant in the sixties. Our normal production rate was 10,000 carsets a day, or 2 million a year. That was for all car and light truck lines combined, so figure 1/10 of that, or 1000 cars a day, or 200,000 cars a year, for a successful line.

Further corroboration: GM killed the fourth generation Camaro/Firebird for low sales, and they sold an average of almost 80,000 cars a year for model years 1996..2001.

By way of illumination, Corvette sales for the same period averaged 27,427 cars/year. We know the Corvette survives partly as a flagship and partly because of a lot of internal and external zealots.

Let's look at a lower production car; the Porsche Boxster, of which just over 200,000 have been built in 14 years, for an average of 14,285/year.

Are there enough green zealots who will _say_ they'll buy 10,000 tiny, slow cars a year? Probably. Will they pay somewhere upward of $50,000 for it? Probably not. Could anyone build it to sell for less than that? Not if they have to buy any tooling.







Mike Halloran
Pembroke Pines, FL, USA

 

[MikeHalloran]

"Not if they have to buy any tooling."

Which of course is what Greg said, in far fewer words.



Mike Halloran
Pembroke Pines, FL, USA

 

[EdDanzer]

The Automotive X Prize Mainstream car entries can’t be tiny or slow. It must go 0-60 in 12 seconds, have a minimum 100 mph top speed and fit 4 people in the 95 percentile in size. Not that I know how big that is.