jeremys73

I've been wondering about MPG vs. GPH (gallons per hour) and it's relation to mpg. I've always wished that vehicle mfg's would be required to install hour meters (like tractors and boats) along with the tripometer so you could have more information on how the car was driven and how many hours it has ran.


Also it's interesting that you may get better mpg's on the highway, but you get much less gph's driving on the highway compared to city driving... or more importantly trail driving. Thinking of it like it was a portable generator, a generator will run longer on a smaller load.
I did a quick calculation on excel but it's just a straight calculation of avg. mph. Maybe someone has some more information on how many hours they get out of a tank of gas on the trail and what their mpg was on that trip. It would be interesting to have one of these

.Hwy
Gallons.18
Avg mph.60
MPG.20
.
Miles Traveled.360
Hours.6

-City
Gallons-18
Avg mph-25
MPG-17
-
Miles Traveled-306
Hours-12.24

JHupp

some newer trucks have the hour meter, my 250 came with it, and most utility trucks carry one. I dont really find a need for it, on my runner, on the 250 though whenever I go camping, the truck idles for long times, and our utitlty trucks idle for a full day sometimes. We always change the oil by the hour meter, which is its main use. In larger utility vehicles an oil change may occur after as little as 1000 miles,because the truck has reach 3,000 hours(oil change depends on type of oil used)

Flamedx4

Yep, it's interesting. Boats and planes worry about GPH, but it's still GPH at various speeds. Without the speed integration, or at least distance traveled (as you noted in your comparison above) GPH by itself is essentially useless. For instance, at idle you'll burn 0.2 to 0.3 GPH, but get Zero MPG. Hardly a good use for fuel...

Note that trip computers use fuel flow meters to get GPH (or GPM) and then compare speed to calculate current MPG and Miles Remaining in tank at current speed. Its fun to see stuff like 80 mpg when coasting and 0 mpg at idle...