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-   -   The ultimate efficiency 4-passenger car (https://ecomodder.com/forum/showthread.php/ultimate-efficiency-4-passenger-car-8353.html)

Ernie Rogers 05-13-2009 02:42 PM

The ultimate efficiency 4-passenger car
 
Hello, folks,

I wrote a nine-page analysis for the Sierra Club on what they should expect for the likely efficiency of a personal automobile at some time in future, say 10 or 20 years from now. (Or, maybe sooner.) I think you can access it here:

http://ecomodder.com/AutomobileEfficiency.doc

This is a Word file. If you have trouble, let me know, and it will get fixed.

The final conclusion is that this future car will get 150+ miles per gallon at 60 mph on the highway. The EV folks of course will want to know how much electricity it would take as an EV, and I didn't include that in the paper. But I can convert to an EV, given the plug-to-wheels efficiency.

For EV efficiency of 70% (plug to wheels), the future car would use 123 watt-hours per mile at 60 miles an hour.

Ernie Rogers

SVOboy 05-13-2009 02:50 PM

:thumbup: Good work, Ernie.

What exactly is your relationship to the sierra club?

RobertSmalls 05-13-2009 07:30 PM

What do we lack now that we will have in 2030? Why can't you build this 150mpg cruiser in 2009?

I hope lightweight alloys and composites will become more affordable. I'm sure rolling resistance will continue to improve, and I look forward to rolling on future LRR tires. Just be aware that current solar car LRR tires may be too low traction for anything besides solar cars.

Aerodynamics is a mature field. The existence of concept cars from the 1950s with Cd as low as .14 indicates we have been capable of excellent aerodynamics since at least then. The development of computational fluid dynamics may have been the final advancement in aerodynamics research. If automotive Cds continue to decrease, it will not be due to emerging technologies, but to making aero a higher priority during the design process.

A four seat, probably four wheeled, "stretch-Aptera" concept would come close to the pinnacle of fuel efficiency achievable with current technology. Punching the numbers for an Aptera that put on 300lbs into the simulator at Aerodynamic & rolling resistance, power & MPG calculator - EcoModder.com , we get an amazing 158mpg at 60mph steady-state cruise. EPA fuel economy would be much less, maybe 100mpg? If there were enough demand for it, it could sell for $30-40k.

MetroMPG 05-13-2009 09:15 PM

Quote:

Originally Posted by RobertSmalls (Post 104080)
What do we lack now that we will have in 2030?

Perhaps the constraints of "consumer acceptability"?

That's the limiting factor the automakers routinely march out as a reason to shoot down ideas that stray from where they really want us to be.

jamesqf 05-14-2009 01:02 AM

One big question: why on earth should a PERSONAL automobile carry four passengers? Get past that mental block, and you have room to cut weight & improve efficiency even further.

Of course there's also a market for family cars, that can carry four or more, but there's a large percentage of the population that doesn't need cars this size.

Ernie Rogers 05-14-2009 01:32 AM

Quote:

Originally Posted by SVOboy (Post 103987)
:thumbup: Good work, Ernie.

What exactly is your relationship to the sierra club?

Member, transportation expert /chair in Provo, Utah

Ernie Rogers 05-14-2009 01:42 AM

I agree, Robert,

Mostly we are waiting for industry inertia. Uhh, the Aptera is an EV?

If you are talking about mpg equivalent, I wasn't for the new car. You can check my calculations--punch my design parameters into the program. Present engines can't deliver 150 mpg until you get about 40% efficiency, which isn't available yet.

Quote:

Originally Posted by RobertSmalls (Post 104080)
What do we lack now that we will have in 2030? Why can't you build this 150mpg cruiser in 2009?

I hope lightweight alloys and composites will become more affordable. I'm sure rolling resistance will continue to improve, and I look forward to rolling on future LRR tires. Just be aware that current solar car LRR tires may be too low traction for anything besides solar cars.

Aerodynamics is a mature field. The existence of concept cars from the 1950s with Cd as low as .14 indicates we have been capable of excellent aerodynamics since at least then. The development of computational fluid dynamics may have been the final advancement in aerodynamics research. If automotive Cds continue to decrease, it will not be due to emerging technologies, but to making aero a higher priority during the design process.

A four seat, probably four wheeled, "stretch-Aptera" concept would come close to the pinnacle of fuel efficiency achievable with current technology. Punching the numbers for an Aptera that put on 300lbs into the simulator at Aerodynamic & rolling resistance, power & MPG calculator - EcoModder.com , we get an amazing 158mpg at 60mph steady-state cruise. EPA fuel economy would be much less, maybe 100mpg? If there were enough demand for it, it could sell for $30-40k.


Ernie Rogers 05-14-2009 01:45 AM

Quote:

Originally Posted by jamesqf (Post 104162)
One big question: why on earth should a PERSONAL automobile carry four passengers? Get past that mental block, and you have room to cut weight & improve efficiency even further.

Of course there's also a market for family cars, that can carry four or more, but there's a large percentage of the population that doesn't need cars this size.

James, your problem is simple-- you are smarter than the average U.S. car buyer, who thinks he needs to cover all possible uses in just one car size and shape.

Ernie

Bicycle Bob 05-14-2009 01:57 AM

So, the Sierra Club thinks that climate change and current trends allow economic predictions more than a decade distant? I wish I found this reassuring.

CapriRacer 05-14-2009 09:42 AM

Quote:

Originally Posted by RobertSmalls (Post 104080)
What do we lack now that we will have in 2030? Why can't you build this 150mpg cruiser in 2009?

........



Quote:

Originally Posted by MetroMPG (Post 104104)
Perhaps the constraints of "consumer acceptability"?

That's the limiting factor the automakers routinely march out as a reason to shoot down ideas that stray from where they really want us to be.

Consider for the moment that this same question was asked during the 1973 oil embargo, when, interestingly, the price of gasoline quadrupled (Sound familiar?) Cars back then didn't have as standard equipment: Air conditioning, electric windows, cruise control, automatic transmissions, etc.

If vehicles had stayed the same during this entire time, the technological improvments would have resulted in improvements in fuel economy as suggested. However, vehicles that sell today have higher acceleration rates, better crash survivability, less harmful emmissions, more luxurious features, better sound insulation - but they are also heavier. As Ernie pointed out in his article, weight = fuel consumption.

Nope, The problem is you and me and what we are willing to accept.


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