A new standard for vehicle MPG ratings

[danbucks]

With the introduction of many new fuels and technologies, MPG - and even MPGe - is a weak and confusing standard (note current threads - e.g. Aptera, who really makes it confusing and pretty much unintelligible noise to the uninformed customer, intentionally in their favor as a PHEV).

surely we can do better.
Here is an over-beer stab at a simple rating system:

Measure vehicles simply by the energy (from any source) they consume - i.e. measured in joules or KWh or whatever, not in terms of MPG.
-measure this for the vehicle going 65-75 MPH, flat surface, stationary
-measure this for the vehicle going 25-35 MPH (or wherever wind resistance becomes negligible in terms of energy consumption), at 9-11% grade (or something close to that, a function of inclines used today for most roads)
-measure this for the vehicle going from 0-35 MPH and back down to 0 in K seconds, where K is within an *allowed range* centered around E(traffic stop/go across the entire US)

note: energy consumed in the measured above should be the COMPLETE energy lost *creating* fuel/energy source, and "burning"/using it, to achieve measurements above.

The vehicle gets three numbers that are standardized (units, and background can be stripped for the confused, non-scientific buyers):
1) "highway" (somewhat as normal) efficiency - really "aerodynamics", rolling resistance ignored.
2) "climb" (new) efficiency - really efficiency at high sustained load
3) "acceleration" or "stop/go" (replacement for "city") efficiency

TBD: emission rating standards - probably thousands of posts at flytheroad etc. go back and forth on this, since CO2 vs. other emissions vs pollution in creating the energy source in the first place, etc. all come into play.

All of the above can be converted to a MPGe guideline if the consumer is demanding what cost of travel might be.

back to the beer...

[RAN]

Jeez, *I* need a beer now! :Beer:

[Mark Tomlinson]

Good stab!

Your note about the energy consumed needs to be stressed. How much power it takes to push the car is irrelevant if we've got an inefficient generator.

The bottom line is that a consumer wants to know how this vehicle rates against his or her other choices. Today those other choices include hybrids and straight ICEs. In the future those other choices could be all over the map. So what we're looking for is a layman's view of how much it's going to cost said layman to run the vehicle.

Aptara's chart goes part of the way because I can superimpose my 22mpg Saturn over it and decide which makes more sense for my 50 mile daily commute. But it doesn't illustrate the hard cut-off between battery-only and hybrid mode. Your suggestion helps, but there's no way I can compare that to other vehicles unless the EPA changes all the ratings for all vehicles.

Personally, I'd like to see each "mode" of a vehicle rated seperatly with expected range. Battery-only would have city and highway kwh with expected range of each. The same for hybrid mode. And we already have it for ICE only. Fourty mpg for hybrid mode might not look so bad if I get 50 miles on an efficient battery-only mode. But if I was a traveling salesman, I might be more inclined to look at the hybrid figures more closely.

[Mark Tomlinson]

Regarding emissions standards; this is where I think the government needs to rip and replace the current standard. I'm sure we've all heard the "long tailpipe" argument that electric vehicles just move pollution to the power plant. Well, the counter-argument usually says something about how much pollution drilling for oil, refining it, and shipping it creates.

My suggestion is that the well-to-wheel measurement should be used. The EPA already has these figures. Regardless if the "well" is a coal mine for coal-fired power plants or an oil well, a consistent measurement for all vehicles can be found. The measurement would have to be updated annually to account for ancient coal-fired power plants being taken off-line. And it may have to be adjusted locally depending one your energy sources.