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

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 04-24-2013, 05:47 PM   #1 (permalink)
EcoModding Lurker
 
Join Date: Mar 2013
Location: vacouver, Canada
Posts: 29
Thanks: 0
Thanked 1 Time in 1 Post
10 degree C change and no MPG change?

Can anyone with experience tell me how much does temperature affect MPG?

My car has drove through winter with virtually no change in fuel comsumption. Though the winter is mild here, so how much % will 10 degree C affect fuel comsumption?

  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 04-24-2013, 07:13 PM   #2 (permalink)
Efficiency Aficionado
 
CigaR007's Avatar
 
Join Date: Jul 2010
Location: Province of Québec
Posts: 605

GreenTurtle - '01 Toyota Echo Sedan
90 day: 44.85 mpg (US)

Zulu - '14 Honda CR-Z
90 day: 39.58 mpg (US)
Thanks: 135
Thanked 135 Times in 94 Posts
Here's an interesting discussion on the matter.

http://ecomodder.com/forum/showthrea...cts-20561.html
__________________
Mauricio
  Reply With Quote
Old 04-25-2013, 10:33 AM   #3 (permalink)
Master EcoModder
 
Join Date: Jul 2008
Location: NY state
Posts: 485

XJ Cherokee - '00 Jeep Cherokee Sport
90 day: 12.96 mpg (US)

FoFO - '11 Ford Focus SE
90 day: 36.78 mpg (US)
Thanks: 1
Thanked 48 Times in 36 Posts
This week commuting to and from work, I'm averaging 37MPG ... which is pretty on par with what I usually get out of the Focus during summer commuting.

In the winter with winter blend fuel, colder temperatures and snow tires I struggle to get above 31MPG.
  Reply With Quote
Old 04-25-2013, 04:53 PM   #4 (permalink)
Batman Junior
 
MetroMPG's Avatar
 
Join Date: Nov 2007
Location: 1000 Islands, Ontario, Canada
Posts: 21,536

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

MPGiata - '90 Mazda Miata
90 day: 52.8 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)
Thanks: 3,303
Thanked 6,114 Times in 3,172 Posts
Keep in mind jayliu's location: Vancouver, BC has a temperate climate: mild summers, and doesn't see very many days below freezing in the winter.

So the seasonal fuel economy variation due to ambient temperature won't be as extreme as most other places.
__________________
Latest mods: 3-cylinder Mitsubishi Mirage. EcoMods now 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 04-29-2013, 04:23 PM   #5 (permalink)
Master EcoModder
 
Diesel_Dave's Avatar
 
Join Date: May 2011
Location: Indiana
Posts: 1,194

White Whale - '07 Dodge Ram 2500 ST Quad Cab 2wd, short bed
Team Cummins
90 day: 37.68 mpg (US)
Thanks: 112
Thanked 502 Times in 211 Posts
We've had several threads on the topic. My data, as well as several others, has yeilded a rough rule of thumb: 1% FE change per 2 deg F temperature change (roughly 1% per 1 deg C).
__________________
Diesel Dave

My version of energy storage is called "momentum".
My version of regenerative braking is called "bump starting".

1 Year Avg (Every Mile Traveled) = 47.8 mpg

BEST TANK: 2,009.6 mi on 35 gal (57.42 mpg): http://ecomodder.com/forum/showthrea...5-a-26259.html


  Reply With Quote
Old 05-08-2013, 11:42 AM   #6 (permalink)
EcoModding Lurker
 
Join Date: May 2013
Location: Maryland
Posts: 22

Cam - '94 Toyota Camry LE
Thanks: 17
Thanked 1 Time in 1 Post
Hm, so according to ecomodder's averages, you should be seeing a 10% change in MPG.

However, the general FE rule may still apply for you. In my area, traffic goes up when the weather is nice (when its warm out), so the higher MPG in warmer weather may be counter-acted by increased traffic.

Anyone know why FE goes up when its warm? I assume cold weather most affects the car while its warming up. A colder car takes longer to warm up and a car is least efficient when its cold (not to mention bad for the engine). Regular tires also perform worse when cold. That part makes sense to me.

However, isn't air denser when its cold? Isn't this the same effect as forced induction, jut without turbo or supercharger drag? Therefore wouldn't FE increase in cold weather, assuming the car is fully warmed-up? (By this logic, cold weather should increase FE for longer drives?)
  Reply With Quote
Old 05-08-2013, 12:23 PM   #7 (permalink)
Master EcoModder
 
Diesel_Dave's Avatar
 
Join Date: May 2011
Location: Indiana
Posts: 1,194

White Whale - '07 Dodge Ram 2500 ST Quad Cab 2wd, short bed
Team Cummins
90 day: 37.68 mpg (US)
Thanks: 112
Thanked 502 Times in 211 Posts
There are several effects of the cold:

1) Increased rolling resistance. Tires absorb more energy when cold, so it takes more energy to roll. Also, cold lubricants in differentials, transmissions, etc. are also more viscous which hurts FE.

2) Increased drag. Increased air density means more aero drag. A 10 deg C decrease in temp means ~4% denser air, which means 4% more drag.

3) Slower warm-up. The engine looses more heat to the ambient when cold. Also, the cold engine & transmission oil make it more viscous and cause more friction

4) Cooler, more dense intake air. This typically hurts a typical gasoline engine. The reasons are the same as why a warm air intake helps a gasser. Colder air means the throttle closes down more and pumping losses go up. Also fuel doesn't evaporate asnd mix as well, and flame speed goes down. On a diesel, cooler air typically has a slight benefit, at least to a point. Very cold air can delay the combustion and hurt FE.

__________________
Diesel Dave

My version of energy storage is called "momentum".
My version of regenerative braking is called "bump starting".

1 Year Avg (Every Mile Traveled) = 47.8 mpg

BEST TANK: 2,009.6 mi on 35 gal (57.42 mpg): http://ecomodder.com/forum/showthrea...5-a-26259.html


  Reply With Quote
The Following User Says Thank You to Diesel_Dave For This Useful Post:
riva2model64 (05-08-2013)
Reply  Post New Thread


Thread Tools




Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2020, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com