Aug-06-2020 12:01 PM
Aug-07-2020 09:16 PM
JRscooby wrote:bjbear wrote:JRscooby wrote:
My '95 3406 drank.... The temp of fuel going in the tank had much more effect on MPG than percent of bio.....
Can you explain a little more about you comment about fuel temperature affecting MPG?
We buy fuel measured in gallons, with is volume. Most liquids, get more dense as they cool. Fill the tank up to brim on a hot day, leave it set, and pretty soon the tank is overflowing. If a station was to buy 10,000 gallons of fuel that was 60* when it was put in the delivery tanker, then let it warm up to 80*, sell 10,000 gallons, they would still have fuel in the tank. There is less energy in a given volume of fuel, if the fuel is 80* instead of 60*.
Very few RVs will burn enough fuel for it to be a issue, but this has been a issue for trucking industry for a long time. The large fleets, that buy most of their fuel by the tanker load, get to use the growth in tank. When I was working if the nozzle did not feel cold after I had pumped a few gallons, I would mark my truckstop book not to fuel there.
Aug-07-2020 01:56 PM
Aug-07-2020 01:52 PM
bjbear wrote:JRscooby wrote:bjbear wrote:JRscooby wrote:
My '95 3406 drank.... The temp of fuel going in the tank had much more effect on MPG than percent of bio.....
Can you explain a little more about you comment about fuel temperature affecting MPG?
We buy fuel measured in gallons, with is volume. Most liquids, get more dense as they cool. Fill the tank up to brim on a hot day, leave it set, and pretty soon the tank is overflowing. If a station was to buy 10,000 gallons of fuel that was 60* when it was put in the delivery tanker, then let it warm up to 80*, sell 10,000 gallons, they would still have fuel in the tank. There is less energy in a given volume of fuel, if the fuel is 80* instead of 60*.
Very few RVs will burn enough fuel for it to be a issue, but this has been a issue for trucking industry for a long time. The large fleets, that buy most of their fuel by the tanker load, get to use the growth in tank. When I was working if the nozzle did not feel cold after I had pumped a few gallons, I would mark my truckstop book not to fuel there.
Thanks for the info. I live in Canada, but travel to the US every winter. Up here in Canada, they calibrate the fuel pumps on a regular basis and certify the volumes delivered. They actually have minions that travel around and use each pump to fill an "official" measuring container and then adjust the pump as required.
I assumed they did the same in the US, but obviously not based on your experience. I'll have to pay more attention next time I am in the US (if this Covid-19 thing ever does away!!)
Aug-07-2020 01:43 PM
wolfe10 wrote:
No, the point is that an exact volume of fuel at 40 degrees F will show the same exact volume if pumped at 90 degrees F. Pump accuracy is not the issue.
BUT, there will be fewer molecules in that volume at the higher temperature.
So, if you put 10,000 gallons in a storage tank at 40 degrees F and pump it out at 90 degrees F, you will still have those "molecules" left in the storage tank.
https://www.onsitepoweradvisor.com/2012/12/03/thermal-expansion/
The coefficient of expansion for diesel fuel is 0.00046 per degree Fahrenheit, or roughly 1% per every 20°F increase in temperature.The coefficient of expansion for diesel fuel is 0.00046 per degree Fahrenheit, or roughly 1% per every 20°F increase in temperature.
Aug-07-2020 01:12 PM
Aug-07-2020 12:21 PM
JRscooby wrote:bjbear wrote:JRscooby wrote:
My '95 3406 drank.... The temp of fuel going in the tank had much more effect on MPG than percent of bio.....
Can you explain a little more about you comment about fuel temperature affecting MPG?
We buy fuel measured in gallons, with is volume. Most liquids, get more dense as they cool. Fill the tank up to brim on a hot day, leave it set, and pretty soon the tank is overflowing. If a station was to buy 10,000 gallons of fuel that was 60* when it was put in the delivery tanker, then let it warm up to 80*, sell 10,000 gallons, they would still have fuel in the tank. There is less energy in a given volume of fuel, if the fuel is 80* instead of 60*.
Very few RVs will burn enough fuel for it to be a issue, but this has been a issue for trucking industry for a long time. The large fleets, that buy most of their fuel by the tanker load, get to use the growth in tank. When I was working if the nozzle did not feel cold after I had pumped a few gallons, I would mark my truckstop book not to fuel there.
Aug-07-2020 11:59 AM
bjbear wrote:JRscooby wrote:
My '95 3406 drank.... The temp of fuel going in the tank had much more effect on MPG than percent of bio.....
Can you explain a little more about you comment about fuel temperature affecting MPG?
Aug-07-2020 07:05 AM
JRscooby wrote:
My '95 3406 drank.... The temp of fuel going in the tank had much more effect on MPG than percent of bio.....
Aug-07-2020 06:54 AM
Aug-06-2020 06:25 PM
Aug-06-2020 04:58 PM
Aug-06-2020 02:54 PM
Aug-06-2020 01:08 PM