Saturday, June 9, 2007

Automotive Darwin Award Nominee

I don't think this guy died, but I do think we need an automotive version of the famous Darwin Awards--people who do the stupidest things, and wind up wrecking their cars.


New Jeep Isnt Trail Rated - Watch more free videos

Friday, June 8, 2007

The Fuel Economy Trade-Off Game








































































































Technology/Technique

Cost

Safety

Convenience

Durability

Fuel Save

Total

Comments

Reduce Mass: downsize

+1

-2

-2

0

+1

-2

Americans like big roomy cars.
Safety suffers due to interface with older cars.

Reduce Mass: materials

-1

-1

0

0

+1

-1

Al, Mg, carbon fiber cost more.

Reduce Engine Output

+1

0

-2

0

+1

0

Americans like powerful cars.

Mild Hybrid Powertrain

-1

0

0

-1

+1

-1

More complexity (batteries,
generator) hurts durability.

Full Hybrid Powertrain

-2

0

-1

-1

+2

-2

Even more complexity.

Gas Turbo Direct Injection

-1

0

0

-1

+1

-1

More complexity.

Flex Fuel (Ethanol)

0

0

-1

0

+1*

0 (-1)

Fuel availability problems; less
gas used, but nearly same carbon output.

Passenger Car Diesel

-1

0

0

-1

+2

0

More complexity due to emissions
regs.

Hydrogen Fuel Cells

-1

0

0

+1

+3

+3

Still a research project.



How do you compare the different ways to increase fuel economy? If you are an engineer, you might make a table which assigns weights to different characteristics and then levels for each one. Combine the numbers, and you have a handy way to compare different choices.

Here is a swag at the fuel economy trade off game, according to my near-expert opinion. The method is to equally weight Cost, Safety, Convenience, Durability, and Fuel Economy. -2 means big decline (more cost, less safety, less convenience, less durability), while a +2 means a big improvement (less cost, more safety, more convenience, etc.). Minus bad, plus good.

So, the way I see it, for a modest fuel savings, the best all around technique is to reduce power, followed by gas turbo direct injection. For large fuel savings, the light diesel seems best. The Holy Grail, as always, is the hydrogen fuel cell.

What is inevitable is that you can't have everything--this is a law of engineering, where physics and economics meet. Want lots of power? Lose weight (and safety). Want safety and fuel economy? Gain cost.

We Americans need to have a serious discussion about what it is we really want, and we need to tell our legislators. What are we willing to give up?

OK, Edmunds just posted a great article which assigns grades to the various fuel saving technologies. You may not believe me, but in fact I was working on the same type of post. I was trying to figure out how to make the table work right.

Sunday, June 3, 2007

Monster Camper Van

The other day, this monster van showed up in one of the parking lots not far from my house. I couldn't help but notice it, and quietly snapped a couple of pictures.



A quick trip to Google, and I learn all about it. The builder is an outfit called Sportsmobile, which starts the process with a Ford or Chevy van or Dodge (Mercedes) Sprinter. Various interior amenities are added, such as a head, beds, mini-kitchen, swiveling chairs, and cabinets. A pop-up camper roof can also be added.

The example in my neighborhood is a top of the line specimen, as it has been given a Quigley 4x4 conversion in addition to the camper treatment. This van would cost approximately $70,000!

A nice trailer or 5th wheel camper plus a 4x4 truck to tow it seems like a better deal, to me, since you can use the truck for many non-camping activities, and you would have a much larger living space as well. Even if it doesn't make the most sense to me, these monster vans are an impressive product.

Friday, June 1, 2007

Comparing Cars--SpD

Recently, MotorTrend tested a bunch of high performance cars, and presented the results as spiderwebs, with a combined performance number based on things like steering accuracy, brake feel, roadholding, etc. The result was neat, but not practically useful because it didn't factor in cost.

Then Winding Road got in the game, and proposed the Speed/Dollar index, which is HP/weight/price * fudge factor.

A problem with the SpD metric is that it only cares about power/weight ratio, which can favor cheap cars with big engines, such as the Mustang GT, or even a V8 Chevy family hauler. Nice in a straight line, but what if you are interested in autocross or rallying?

I think a better metric would be something like (HP/Weight + Slalom Speed/60)/Price * K, which would add a dynamic handling component--the speed through a slalom course, in this example. Or perhaps a lap time or average speed around a reference track would be better.

Both Winding Road and Motor Trend put the MazdaSpeed 3 near the top of their list, in terms of bang-for-the buck. Now I want one.