Why "Gallons Per Mile" (or L/100 km) makes more sense

[MetroMPG]

Originally Posted by .Cd

I found this the other day in a magazine ad :
Hmmmm....

Haha - "45-55 gallons of gas per mile"

In a smart car! I think he needs a tune up.

[MetroMPG]

Originally Posted by tasdrouille

You just proved the article is right.

And dremd got it first try. Thanks for showing your work, tasdrouille.

I sometimes actually use that type of info, so it's not just a "brain teaser" concern.

Wanting to get a certain round trip mpg, if conditions on the two legs are going to be different, at the end of the first leg I need to know what my return leg fuel consumption should be to attain my round trip target. It's easier to figure out using gal/mi or L/100 km than using MPG. Unfortunately, the ScanGauge doesn't help me there.

[RH77]

Originally Posted by MetroMPG

And dremd got it first try. Thanks for showing your work, tasdrouille.

I thought it was a trick question -- like perhaps the vehicle didn't have a full SOC on return, so the tank mileage would have to reflect future trips of charging the batts.

Also, it was around 11 pm and it looked like one of those word problems...

A train leaves New York, averaging 55 mph for Chicago. The Chicago train leaves with an average of 70 mph...


RH77

[ebacherville]

Originally Posted by jamesqf

Maybe that should be an additional function on your trip meters. You plug in the cost of gas, it displays the cost of your trip...

the scan gauge does this FYI

[jamesqf]

Originally Posted by tasdrouille

You just proved the article is right. Suppose 50 miles. At 50 mpg you use 1 gal and at 100 mpg you use 0.5 gal. Total fuel for the 100 miles trip is 1.5 gal which turns out to be 66.6667 mpg.

Nope, just proved that the poster didn't pay attention in math class :-)

And of course the problem is not realistic: If I get 50 mpg on an uphill in the Insight, I'll get close to infinite mpg on the reverse trip :-)

[jamesqf]

Originally Posted by ebacherville

the scan gauge does this FYI

Maybe with the latest upgrades, but mine doesn't.

It's also not exactly accurate on anything to do with fuel. Or at least it can show very different numbers from the Insight's built-in gauge and from hand computations.

[Volones]

34.7mpg = 2.88 gal/100mi
Am I correct there?

I like it, and might just write it on my window.

Although I am aiming at topping 40mpg (2.5 gal/100mi) with this tank.

[Blue07CivicEX]

If anybody is bored we could create a dynamic blog for Ecomodder.com that will take the current national average for fuel (I'm guessing US cause I think that's where most people are from?) and make a list of the top 20 most efficient vehicles and the worst 20 vehicles and show the daily miles/$ calculation. So as the price of gas goes up we would see how many miles they're dollar was getting them. (this might also draw in more people googling efficient vehicles)

[jivany]

As a Canuck, I find L/100km is the easiest way to compare fuel economy between countries. Around here we see vehicle advertised with MPG, MPIG, L/100km and km/G. (That last one really irritates me as it's intended to confuse people.) I guess L/100km is also easy for me to convert into $/day as my weekday commute is 110km.

110km @ 7.4L/100km @ $1.30/L ~= $10.50.

$/km (or mile) is the best comparison but it fluctuates too much based on the day (or hour) and location. Not something that can be published easily.

On the topic of fuel consumption ratings, in addition to "city" and "highway" I'd really like to see ratings like:

• 7.0L/100km @ 100km/h
• 10.0L/100km @ 120km/h

Actually, get rid of "highway" ratings and just list what the consumption is at various "typical" highway speeds.

[Gregte]

Originally Posted by Arminius

75 mpg. The wind and the hill info are not necessary for the computation.

The wind and hill info are not necessary but they do explain the mileage difference.

But, the answer is 66 and 2/3 MPG. You can find this by plugging in some assumed miles for the trip. For instance, if the trip is 100 miles up and then of course 100 miles back you would travel a total of 200 miles and burn 3 gallons of gasoline.