Go Back   EcoModder Forum > EcoModding > Hypermiling / EcoDriver's Ed
Register Now
 Register Now
 

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 01-03-2009, 04:16 AM   #1 (permalink)
PaleMelanesian's Disciple
 
hummingbird's Avatar
 
Join Date: Dec 2008
Location: Noida, UP, India
Posts: 197

City - '04 Honda City iDSI EXi
90 day: 47.47 mpg (US)
Thanks: 3
Thanked 3 Times in 2 Posts
Effect of ambient temperature on fuel tank volume

Hi folks,

I am about to log in my first results of a well-driven tank - I have got around 6 L/100 km, on a 1.5L 5 speed manual tranny Honda City. But when I get into the method of getting to my exact FE data, there is problem - as I think -

The SOP for finding FE is Tank up till clip off - reset trip meter - drive around till empty (of course almost empty) go back to the same pump, same orientation - tank up again till clip off - note amount of fuel pumped - note trip meter - divide fuel x 100 by trip meter reading to get L/100 km reading

But here, if there is significant temperature difference between when you tanked up earlier, and now, you will get less gas in the tank when filling up now (relatively colder ambient - shrinkage in the tank volume - less fuel to clip-off). The change in ambient temperature is because I filled my tank in Nov, and now it is almost Jan (quite a stretch in my refilling routine, because of hypermiling techniques, I should admit! )

Would that result in erroneously higher tank mileage? ( i think it will...) Should the SOP be modified? Any ways to calibrate out this error?

Wish you all a happy and fulfilling new year 2009!

PS: How can we prevent the spell check to highlight 'hypermiling' as a spelling mistake when posting? It is so embarrassing...

__________________
  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 01-03-2009, 08:32 PM   #2 (permalink)
Batman Junior
 
MetroMPG's Avatar
 
Join Date: Nov 2007
Location: 1000 Islands, Ontario, Canada
Posts: 22,244

Blackfly - '98 Geo Metro
Team Metro
Last 3: 70.09 mpg (US)

MPGiata - '90 Mazda Miata
90 day: 52.07 mpg (US)

Winter beater Metro - '00 Chevrolet Metro
90 day: 61.98 mpg (US)

Fancy Metro - '14 Mitsubishi Mirage top spec
90 day: 58.72 mpg (US)

Even Fancier Metro - '14 Mitsubishi Mirage top spec
90 day: 70.75 mpg (US)
Thanks: 3,796
Thanked 6,667 Times in 3,453 Posts
We have spell check?

As to your fuel volume question, you could calculate the difference using this information, your tank volume, and the temperatures you experience:

Quote:
Gasoline volume changes approximately 0.125% for every 1C change in temperature (0.058%/F) .
Source: Why have 9/10 cent gasoline pricing? - Arizona motorists deserve Automatic Temperature Compensation of gasoline at the pump!

Note that your specific results will be affected by whether or not your fuel is sold by volume (e.g. as in most of the USA) or by volume-corrected constant energy density (as in Canada).
__________________
Honda mods: Ecomodding my $800 Honda Fit 5-speed beater
Mitsu mods: Oops, I did it again! Bought another cheap, 3-cylinder Mirage. Mods in progress...
Ecodriving test: Manual vs. automatic transmission MPG showdown



EcoModder
has launched a forum for the efficient new Mitsubishi Mirage
www.MetroMPG.com - fuel efficiency info for Geo Metro owners
www.ForkenSwift.com - electric car conversion on a beer budget
  Reply With Quote
Old 01-03-2009, 09:39 PM   #3 (permalink)
NightKnight
 
NachtRitter's Avatar
 
Join Date: Dec 2008
Location: Placerville, CA
Posts: 1,594

RippinRoo - '05 Subaru Legacy Wagon 2.5 GT
Subaru
90 day: 21.16 mpg (US)

Helga - '00 Volkswagen Jetta TDI
TEAM VW AUDI Group
Diesel
90 day: 53.91 mpg (US)

Olga - '03 Volkswagen Jetta Wagon
90 day: 46.24 mpg (US)
Thanks: 303
Thanked 311 Times in 186 Posts
Quote:
Originally Posted by hummingbird View Post
PS: How can we prevent the spell check to highlight 'hypermiling' as a spelling mistake when posting? It is so embarrassing...
The spell check is very likely part of your browser... all you need to do is right click the misspelled word (e.g. "hypermiler") and "Add to Dictionary"
  Reply With Quote
Old 01-04-2009, 04:32 PM   #4 (permalink)
EcoModding Apprentice
 
CobraBall's Avatar
 
Join Date: May 2008
Location: North Texas
Posts: 112
Thanks: 0
Thanked 2 Times in 2 Posts
Volume Correction Factors For Gasoline
Attached Thumbnails
Click image for larger version

Name:	Volume Correction Factors For Gasoline.jpg
Views:	716
Size:	109.5 KB
ID:	2506  
  Reply With Quote
Old 01-04-2009, 08:11 PM   #5 (permalink)
PaleMelanesian's Disciple
 
hummingbird's Avatar
 
Join Date: Dec 2008
Location: Noida, UP, India
Posts: 197

City - '04 Honda City iDSI EXi
90 day: 47.47 mpg (US)
Thanks: 3
Thanked 3 Times in 2 Posts
Great! So now I know that there is a way to correct for the density of the fuel.

But what about the tank volume changes going through that temperature difference?

Also does anybody on EM take these factors into account while fuel logging? Or it is "recognize the facts about density and tank volume changes - bemoan winter for low FE - put in figures from the pump and topup - carry on" business that is the norm?
__________________
  Reply With Quote
Old 01-04-2009, 10:28 PM   #6 (permalink)
Master EcoModder
 
Join Date: Aug 2008
Location: South Dakota
Posts: 460

WonderWagon - '94 Ford Escort LX
Last 3: 51.52 mpg (US)

DaBluOne - '99 Ford Escort SE
90 day: 48.97 mpg (US)

DaRedOne - '99 Ford Escort ZX2 Hot
Thanks: 0
Thanked 15 Times in 4 Posts
If the fuel in your tank is the same temperature as the fuel you're pumping into the tank (a huge - almost certainly unwarranted assumption) - and you know that temperature (it probably isn't air temperature, then you can use the chart CobraBall provided to make a calculation.

I certainly can't speak for everyone here, but I have better things to do with my time than attempt to correct for this factor.

__________________
  Reply With Quote
Reply  Post New Thread


Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Fuel Economy related papers tasdrouille General Efficiency Discussion 41 03-19-2021 06:31 PM
Hydrogen Generator Experiment willy57 DIY / How-to 601 08-23-2016 05:53 AM
mileage computer for a carbureted engine diesel_john Instrumentation 221 05-01-2014 10:38 PM
ElmScan + Customized Scantool Software = data logging! cfg83 Instrumentation 19 08-08-2010 09:24 PM
Smaller Fuel Tank steensn EcoModding Central 5 07-11-2008 01:09 PM



Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com