Looking for outstanding efficiency numbers
 

Hello, guys,

I have a favor to ask--

Today, I am embarking on a great task--beginning of a "white paper" on the potential for greater efficiency in cars. This is for the Sierra Club. I see the matter as logically divided into four or five parts--

1. Aerodynamics
2. Rolling resistance
3. Power plant efficiency
4. Other losses such as accessories, bearings, lubricants, etc.
5. Future prospects outside the paradigm such as pavement
types and modes of car use.

The Sierra Club folks currently are hoping to get CAFE, the "corporate average fuel economy" required for U.S. cars, up to 55 mpg by about 2030. I think they are setting their sights WAY too low. So I am putting together information showing what has already been done, and what we can expect in the near future.

Guys have already responded on the aero list with lots of samples of super-low drag coefficients. Now, I'm proceding down the list.

The tires on my car did about Cd = 0.0065 at 40 psi. (205/60R-16 Michelin Energy MXV4 S8) Well, we know 0.0060 is doable today. But, what are the solar and supermileage cars doing for rolling resistance? Anybody know of lower numbers?

Any other citations on efficiency of components besides tires are wanted too.

Ernie Rogers

Why the Cross post Ernie? Ask a moderator to move it here if appropriate, but please dont fracture the discussion.
http://ecomodder.com/forum/showthrea...help-8245.html

Hi Ernie,

I have written what I think is a comprehensive outline for just such a thing:

More ways for auto makers to build more efficient vehicles - Updated 3 April 09! - Vox

Also, I have made a list of cars to understand and mimic:

Cars to Emulate and Study - Vox

I don't know the specifics offhand, but do you have the time to go about contacting builders of solar cars and such individually? You could just find the shell eco-marathon competition list and call up some of the top contenders and ask them for details.

Help me get it right, DCB
 

Okay, help me get this right. Here is what I think I did--

I asked the Aerodynamics list for examples of very low Cd numbers, indicating that was part of a greater task I was working on. I thanked them for input, and said I would repeat the question under general efficiency for answers on the other items.

Then I posted here, asking for specific info on very low rolling resistance tires, and again showing how it fit into the overall task.

I guess I split my query into two places because it seemed to logically have two homes.

What shall we do? Should we move the aero discussion to here?

Ernie Rogers

Good writing, thanks
 

Thanks, Neil,

I read your two articles. Very good work and pretty thorough.

Ernie

Tires used in super mileage competition....

Michelin makes a special tire in France for the eco-marathon races (these aren't available to the public, not easily at least). It's clincher bike tire but, it's a radial ply. Crr is claimed to be .001 (1kg/ton) and if I recall inflation pressure is somewhere around 50psi (as opposed to a skinny road bike tire which is >100psi).

The tires are super light and super flexible, but VERY susceptible to puncture. I'm not 100%sure of the name, but I've always seen them referenced as eco-marathon radials. They're identifiable by their wide rolling surface and light blue sidewall (http://web.student.chalmers.se/group...Eco08/Eco6.jpg - random google picture with them)

Hi,

On the tires, what I listed in my blog was we should use metal wheels with solid treads for the lowest rolling resistance possible, and then tune the suspension accordingly. The hydraulic pressure developed by the suspension should be used to generate electricity (a la what MIT has done). So, we gain in efficiency and regain some of what would have been waste energy, as well.

Two things come to mind when reading your initial setup:

First: Greater fuel savings can be achieved when suggesting a minimum CAFE mileage for all vehicles. At 15,000 miles/yr going from 20 to 25 mpg saves as much fuel as going from 40 to 66.6 mpg. Imagine all pickups and SUVs on the road averaging 25+ mpg... Isn't it the reduction of oil dependency/consumption that we are striving for?

Second: I see no mention on driver education. We all know that one can quite easily improve mileage without any physical modifications by 20%-30%, all by just changing the way one drives.

All that being said, a big thumbs up ( :thumbup: ) for dedicating time to writing a white paper on these issues.

My bad, I'm slow.

A few comments (in no particular order) from the official site Grinch:

1.You are looking to improve the average MPG to a figure that is a third better than the fleet leaders in 20 years. A bridge too far?
2.To get to a fleet average of 55 MPG, you’ll have to be selling a lot of (slightly) powered street luges even if the new minivans and pickups get 30-35 MPG.
3.Neil has the aero angle covered. Aptera/VW 1L/Pillbug shapes will have to predominate. Tandem arrangements will have to become the “normal” vehicle to cut frontal area.
4.Federal crash standards will have to be relaxed in order to reduce vehicle weight and still be of reasonable cost. The way the regs are written today, the heavier vehicle is more likely to comply. Yes, you can make your car out of superunobtainium and pass the crash tests and still be light but what have you gained if nobody can afford it?
5.We have to get some cooperation from the government on aero issues like side mirrors and on engine requirements like Tier II on diesels. Heat engines are a fairly mature technology. Barring a materials breakthrough, I would not look for much in the way of improved engine efficiency.
6.A big item, nobody else has mentioned: The torque converter automatic has to go. Maybe the dual-clutch transmissions will supplant it. Maybe not – the jury is still out on that one. We all know the manual is king of MPG, but few people want them. I like a stick but am considered an oddball for that preference.
7.I concur with superchow in that driver education & motivation will probably be more important than you think. There is a yawning gap between the performance of a Wayne Gerdes and my texting-while-driving niece. The importance of the nut behind the wheel is an article of faith on this site.
8.The cars of this brave new world will have to be designed to be fairly comfortable and accessible. One thing that designers have found is that people strongly prefer to sit fairly upright rather than reclining. You do have to sell the things to people who are NOT Olympic gymnasts.
9.The history of the auto industry shows that (for some reason) people do not like aero vehicles. People tell me my (slightly) modified truck looks “gay.” The basjoos-mobile would probably trip all their breakers. It seems dumb to me, but automotive history is full of aero cars that people didn’t want.
10.A mandated jump in MPG this big, this fast carries a high risk of political backlash. Maybe a better way to reduce air emissions is to take some intermediate steps toward an electrified ground transportation system. That takes the propulsion of ground transportation away from inherently dirtier mobile power plants and toward inherently cleaner stationary power sources. You cannot get cleaner than nuclear power. The first step would be to subsidize/encourage electrification of America’s freight railroad mainlines. Railroads consume about a quarter million barrels a day of diesel fuel. If that is shifted to nuclear or even stationary coal power there would be big net reduction in air emissions. Once that is accomplished you then put electrified lanes on the Interstates for trucks and busses. This would bring an even larger reduction in air emissions.
11.Low rolling resistance tires carry a big downside. Generally “low rolling resistance” equals “poor traction.” One reason tire manufacturers don’t publish crr to the general public is that they are afraid that in a period of high fuel costs, people will mindlessly buy the low-crr tires and ignore the trade-offs made. They will have accidents and will litigate against the tire manufacturers for making “unsafe” tires. It won’t take but a couple of gullible juries and “lottery” awards and low-crr tires will disappear from the market. I would not bet on low rolling resistance tires being around very long in a highly litigious society.
12.Energy recovery from potholes is a seductive idea, but at what price in terms of cost and complexity?

Remember that whatever is done will still have to pass muster with the consumer.

My take, and even why I am here at eco mod, is the boxer engine. The net has only fulfilled a hunch already.

If to target powerplant,(I see it as a task in the list you made) scrap the inline, and even transverse. the babbles all the way to "type of pavement" will seem to come from a ninny who doesn't know what torque for fantastic consumption is, after using a boxer with 3 mains. That applies to aerodynamics as well. A balanced drivetrain (that means for real, no counterbalancers pretending pistons and rod weight, I mean a benz crank type balance) does away with a whoooole lot of crazy theroies (crazy to me, and any long term boxer driver).

In fact to add to mainstream frustration, I am going to put a welded home made whistling in the wind steel roof rack on the sube some day, and know 40mpg is not even going to be bothered whatsoever...with 1781cc carrying it ALL. 10 gears, 15 inch wheels buzzing like monster treads and cruising behind the v8 bimmer in the 80s mph on a typical chauvinist highway. :rolleyes:

Ernie FYI, I know it isn't for everybody, but Craig Vetter had some motorcycle efficiency contest back in the 80s, and one fella got his bike up to 470mpg, nothing mechanically fancy, mostly just fiberglass aero, gearing, and stroking, and technique. 62 miles on California hiways in real conditions.
1985 Fuel Economy Contest

So be kind to your two wheeled friends.

You're the man
 

You're the MAN. :)

Now, back to work.

Ernie

I like #6
 

Well, Big Dave,

I agree with #6.

And, I think your truck is awesome!

If I figure out how to post it, I have about an eight-page draft of a discussion on car energy efficiency--not good enough to call a "white paper."

My conclusion is that in a couple of decades, maybe less, we should have comfortable-size cars that get up to 150 miles per gallon (at 60 mph).

Ernie Rogers

Thanks, very good
 

Thanks,

I needed that information. /Ernie

I suppose that it you get enough (about 40%) of the cars being HyperRocket trikes you might get 55 MPG CAFE.

I wonder if there will be any auto companies left in 20 years.