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EPA Proposes Grading System For Car Fuel Economy
suraj.sun writes with this snippet from CNET:
"The EPA and Department of Transportation on Monday proposed a fuel economy label overhaul to reflect how electric and alternative fuel vehicles stack up against gasoline passenger vehicles. ... The changed label, mandated by the 2007 energy law, includes the same information on city and highway miles per gallon and estimated driving costs based on 15,000 miles a year now available. But the new labels add more comparative information, rating cars on mileage, greenhouse gas contribution, and other air pollutants from tailpipe emissions. That means that consumers can look at a label to see how one vehicle compares to all available vehicles, rather than only cars in a specific class. One label proposes grades, ranging from an A-plus to a D. There are no failing grades, since vehicles need to comply with the Clean Air Act."
Just how stupid do you have to be to need a giant letter grade on a car? I hope that version doesn't fly.
a,e,i,o,u and sometimes w and y (at be if of up cwm by)
They already have a 1 to 10 scale on the stickers, how is that any more difficult than an A+ through D system?
'Greenhouse gas emmisions'?
Does this include the source power generation? Of course not, because some regions use wind/solar/nuclear, which have a vastly different greenhouse gas emmsiions then others.
Why not use SIMPLE standard units. It's up to the buyers to know the source of the fuel.
N/m@0-10km/h, 11-50km/h, 51-80km/h, 81-100km/h
All cars can compete on this scale. If a 3000kg SUV takes 40kN/m to go from 0-10km/h, and an all electric 1000kg Prius takes 5kN to achieve the same task, we can figure out what is better.
They should also mandate the energy density be displayed at all fuel pumps/charging stations.
e.g.
diesel: 1000N/L
gasoline: 300N/L
natural gas: 200N/L
(my mind is fuzzy on how to apply this to all-electric, but plenty of the folks on here are smarter then I am), but my point still stands.
Label everything based on the one common denominator: energy.
"The price good men pay for indifference to public affairs is to be ruled by evil men." ~Plato (427-347 BC)
A van that carries 15 people at 15 mpg is not worse for the environment than someone driving a 50mpg vehicle by themselves, but I'm guessing the same ratings will apply. Have they given up on the concept of multi-passenger vehicles and just assume everyone drives alone?
The CO2 emission numbers would be misleading for battery electric and plug-in hybrids because it only states the tailpipe emissions.
Example... A battery-electric vehicle may use 34 KW/h of electricity per 100 miles. According to official data, in the USA, about 0.6 Kg of CO2 is emitted for every KW/h of electricity consumed. So for every 100 miles, about 20 Kg of CO2 is released into the atmosphere. So the data should state that 200g of CO2 is emitted per mile, not the 0g it currently states.
Ignoring other sources of CO2 emission and only looking at tailpipe emissions are misleading for technology which does not have a tailpipe. For example, a battery electric vehicle which uses 40 KW/h of electricity per 100 miles would release more CO2 into the atmosphere than many small gasoline vehicles.
No sig. Move along - nothing to see here.
Honest question here. Why is gallons/100 miles preferable? It's always seemed backwards and clumsy to me.
With gal/100mi, it's more complicated to figure out how much gas you need to go X miles (with miles/gallon, it's simply X/mileage), and it also provides a more useful number when comparing cars. Sure, Car A might need 2.5 gallons/100mi and Car B needs 3 gallons/100mi, but that tells you less about the actual mileage (40 vs. 33.33).
If you can't convince them, convict them.
battery-electric vehicle may use 34 KW/h of electricity
That IS bad. After only 3 years of engine-time, you'll need a full Nuke plant to power just *one* of those.
per 100 miles
Criminey! Assuming it averages about 50mph, that means it'll only take 23 hours to require a 1GW dedicated power plant, and it only gets worse from there!
Can you be Even More Awesome?!
I submitted a comment to the EPA suggesting that the "Gallons / 100 Miles" number be more prominent relative to MPG. (Converting to metric is a lost cause, unfortunately.)
I also suggested that they add "Gallons SAVED per 100 miles" relative to an average car in its class. This statistic can be surprising: switching from a 33mpg Corolla to a 50mpg Prius saves one gallon per 100 miles, but switching from a 10mpg Hummer to a 14mpg Land Rover saves three gallons per 100 miles driven.
Weeks of coding saves hours of planning.
A might need 2.5 gallons/100mi and Car B needs 3 gallons/100mi, but that tells you less about the actual mileage (40 vs. 33.33).
Only because you are used to thinking in terms of distance / fuel volume.
http://michaelsmith.id.au
Most people argue GPM is better for exactly those reasons - it's easier to compare. For example, you have two cars - one that gets 10 mpg and one that gets 33 mpg. You can replace the 10 mpg with one that gets 11 mpg, or replace the 33 mpg car with one that gets 45 mpg. Quick, which saves more gas?:
A) replace the 10 mpg with 11 mpg
B) replace the 33 mpg with 45 mpg
The answer is A. The first changes from 10 gallons per 100 miles to 9 gallons per 100 miles - 1 gallon saved every hundred miles. Option B changes from 3 gallons per 100 miles to 2.2 gallons per 100 miles - less than a gallon saved (per 100 miles). It's completely non-intuitive if you use the backwards "mpg" measurement.
If we just used consumption instead of MPG, we wouldn't have this problem.
Only because you are used to thinking in terms of distance / fuel volume.
Fair enough, but it doesn't answer the fact that the math with GPM is easier.
Do you mean this bit?
With gal/100mi, it's more complicated to figure out how much gas you need to go X miles
If I want to go 200 km and my car uses 10 litre/100km then I need 20 litre. Seems simple to me.
http://michaelsmith.id.au
No, once a car has been graded, the grade shouldn't need to change unless something is done to the car that makes it more fuel efficient somehow.
I have to call BS on that. Yes, there is a bigger increase with A, but the only time this matters at all is if I have 2 vehicles in need of replacement at the same time, money for only one of them, and no pressing preference for utility between them; and then you would have to figure out which you drive more often to get a reasonable determination of which to get.
In reality, it works like this: you have a 20 mpg car in need of replacement. You can replace it with a 25 mpg car, or a 32 mpg car. Quick, which saves more gas?:
A) Replace the 20 mpg with 25 mpg
B) Replace the 20 mpg with 32 mpg.
For direct comparison of savings coming from two completely different situations, yes, gal/100 miles is better. But the combination of events and requirements needed for such a comparison to be at all useful is completely absurd. For nearly all situations the "which number is bigger" method of determining mileage superiority is perfectly adequate.
With gallons/mile, fuel efficiency is linear instead of inverse-linear.
If a car performs really well, it might get an A...
But then a few years down the road, improved technology could make that A rating in 2010 look like a C- or D in 2015, and other "A" rated cars come out that perform far better. Yet the 2010 car still has the "A" rating... so it isn't fairly compared to newer cars.
File under 'M' for 'Manic ranting'
so do the L/KM -> KM/L conversion once, stick it on a sticky note, and use it when you need it. But L/KM makes comparing trip costs(what most usually do, think: "to work", "to inlaws", "to bar") not require any gymnastics.
All of the above was encrypted with a Quad ROT-13 method. Unauthorized decryption is in violation of the DMCA.
However, the mere fact that a coffee machine or a breadmaker is safe doesn't actually make it any use for making coffee or baking bread - in fact, in the UK, makers of nonfunctioning "water treatment" products market them as WRAS approved - which is purely safety testing.
Any commercially sponsored test is flawed. Did you ever see a car magazine give a BMW a bad review? Usually they give critical reviews of second tier manufacturers or small cars, which have near-zero "marketing" budgets, and criticise very expensive cars (that their readers can't afford and whose makers don't advertise with them). I'm happy to pay taxes to an organisation that won't go out of business by telling the truth.
From scarped cliff or quarried stone she cries "A thousand types are gone, I care for nothing, no not one."