Go Back   EcoModder Forum > EcoModding > General Efficiency Discussion
Register Now
 Register Now
 

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 09-08-2018, 10:55 AM   #1 (permalink)
Not Doug
 
Xist's Avatar
 
Join Date: Jun 2012
Location: Show Low, AZ
Posts: 12,225

Chorizo - '00 Honda Civic HX, baby! :D
90 day: 35.35 mpg (US)

Mid-Life Crisis Fighter - '99 Honda Accord LX
90 day: 34.2 mpg (US)

Gramps - '04 Toyota Camry LE
90 day: 35.39 mpg (US)

Don't hit me bro - '05 Toyota Camry LE
90 day: 30.49 mpg (US)
Thanks: 7,253
Thanked 2,229 Times in 1,719 Posts
Engineering Explained: How much fuel does idling consume?

Second question: How much fuel does starting the engine consume and at what point would you save gas by turning off the air conditioning (and engine)?

I had read it was eight seconds' worth. He cited a study from 2004 that said about 6.7 seconds, so my information was 19% off. However, they surveyed 1,300 viewers who guessed, on average, 3.6 minutes.

3,100% longer.

I had an Ultragauge in my Forester and it said she consumed .25 gallons per minute hour [Thanks Frank Lee!] in neutral and .26 in park. My dead girlfriend broke my Ultragauge and I have not replaced it, so I do not have data on my Hondas, but it must be less, right?



Last edited by Xist; 09-08-2018 at 11:42 AM..
  Reply With Quote
The Following 4 Users Say Thank You to Xist For This Useful Post:
Daschicken (09-11-2018), Gasoline Fumes (09-12-2018), Joggernot (09-11-2018), OrisDentalCentre (09-20-2018)
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 09-08-2018, 11:11 AM   #2 (permalink)
(:
 
Frank Lee's Avatar
 
Join Date: Jan 2008
Location: up north
Posts: 12,762

Blue - '93 Ford Tempo
Last 3: 27.29 mpg (US)

F150 - '94 Ford F150 XLT 4x4
90 day: 18.5 mpg (US)

Sport Coupe - '92 Ford Tempo GL
Last 3: 69.62 mpg (US)

ShWing! - '82 honda gold wing Interstate
90 day: 33.65 mpg (US)

Moon Unit - '98 Mercury Sable LX Wagon
90 day: 21.24 mpg (US)
Thanks: 1,585
Thanked 3,555 Times in 2,218 Posts
Hopefully that's per hour.

I saw that vid before I came here! It was one of his better ones; I especially like the gentle jabs at the shadetree mechanics who form solid opinions without any basis, as Duhmericans are prone to do.
__________________


  Reply With Quote
The Following User Says Thank You to Frank Lee For This Useful Post:
OrisDentalCentre (09-20-2018)
Old 09-08-2018, 11:45 AM   #3 (permalink)
Administrator
 
Daox's Avatar
 
Join Date: Dec 2007
Location: Germantown, WI
Posts: 11,203

CM400E - '81 Honda CM400E
90 day: 51.49 mpg (US)

Daox's Grey Prius - '04 Toyota Prius
Team Toyota
90 day: 49.53 mpg (US)

Daox's Insight - '00 Honda Insight
90 day: 64.33 mpg (US)

Swarthy - '14 Mitsubishi Mirage DE
Mitsubishi
90 day: 56.69 mpg (US)

Daox's Volt - '13 Chevrolet Volt
Thanks: 2,501
Thanked 2,587 Times in 1,554 Posts
Well explained, and definitely nice to see his humor come through a bit more.
__________________
Current project: A better alternator delete
  Reply With Quote
Old 09-10-2018, 11:37 AM   #4 (permalink)
Cyborg ECU
 
California98Civic's Avatar
 
Join Date: Mar 2011
Location: Coastal Southern California
Posts: 6,299

Black and Green - '98 Honda Civic DX Coupe
Team Honda
90 day: 66.42 mpg (US)

Black and Red - '00 Nashbar Custom built eBike
90 day: 3671.43 mpg (US)
Thanks: 2,373
Thanked 2,172 Times in 1,469 Posts
How much fuel used at idle?

So, a 1.5L gasoline engine burns at idle as much fuel in 6.4 or 7 seconds to match the amount of gasoline typically spent to charge the battery enough to restart the engine. Years ago seven seconds was asserted in an EM thread, and it has been my rule of thumb ever since.
__________________
See my car's mod & maintenance thread and my electric bicycle's thread for ongoing projects. I will rebuild Black and Green over decades as parts die, until it becomes a different car of roughly the same shape and color. My minimum fuel economy goal is 55 mpg while averaging posted speed limits. I generally top 60 mpg. See also my Honda manual transmission specs thread.




Last edited by California98Civic; 09-10-2018 at 03:04 PM..
  Reply With Quote
Old 09-10-2018, 12:00 PM   #5 (permalink)
Somewhat crazed
 
Piotrsko's Avatar
 
Join Date: Sep 2013
Location: 1826 miles WSW of Normal
Posts: 4,303
Thanks: 516
Thanked 1,171 Times in 1,033 Posts
Wonder what the calcs are on the f250? It uses 1/3 qt an hour idling
__________________
casual notes from the underground:There are some "experts" out there that in reality don't have a clue as to what they are doing.
  Reply With Quote
Old 09-11-2018, 09:03 AM   #6 (permalink)
Banned
 
Join Date: Oct 2009
Location: Fort Worth, Texas
Posts: 2,442

2004 CTD - '04 DODGE RAM 2500 SLT
Team Cummins
90 day: 19.36 mpg (US)
Thanks: 1,422
Thanked 737 Times in 557 Posts
Engine idle has to take into account prolonged periods. Above five minutes. After which engine rpm needs to be raised to raise oil pressure to near-normal. That’s where one measures fuel consumption at idle.

The diesel Ford will be closer to 1.0/gl-hr. Which should be the conservative number for planning.

.
  Reply With Quote
Old 09-11-2018, 07:49 PM   #7 (permalink)
Master EcoModder
 
oldtamiyaphile's Avatar
 
Join Date: May 2009
Location: Australia
Posts: 1,510

UFI - '12 Fiat 500 Twinair
Team Turbocharged!
90 day: 40.3 mpg (US)

Jeep - '05 Jeep Wrangler Renegade
90 day: 18.09 mpg (US)

R32 - '89 Nissan Skyline

STiG - '16 Renault Trafic 140dCi Energy
90 day: 30.12 mpg (US)

Prius - '05 Toyota Prius
Team Toyota
90 day: 50.25 mpg (US)

Premodded - '49 Ford Freighter
90 day: 13.48 mpg (US)

F-117 - '10 Proton Arena GLSi
Pickups
Mitsubishi
90 day: 37.82 mpg (US)

Ralica - '85 Toyota Celica ST
90 day: 25.23 mpg (US)

Sx4 - '07 Suzuki Sx4
90 day: 32.21 mpg (US)

F-117 (2) - '03 Citroen Xsara VTS
90 day: 30.06 mpg (US)
Thanks: 325
Thanked 452 Times in 319 Posts
Quote:
Originally Posted by Xist View Post
Second question: How much fuel does starting the engine consume and at what point would you save gas by turning off the air conditioning (and engine)?
Ford and BMW are on record at 3 and 5 seconds for their (12v) stop start equipped cars.

Non S/S equipped cars will sometimes go open loop for around 10 seconds after every restart, so you'd have to factor in 10 seconds of open loop acceleration.
__________________






  Reply With Quote
Old 09-11-2018, 08:14 PM   #8 (permalink)
EcoModding Apprentice
 
Join Date: Jun 2012
Location: Florida
Posts: 222
Thanks: 0
Thanked 22 Times in 18 Posts
According to my OBD scanner, my Fiesta ST with 1,6 liter turbo, idles around 0.4l/h (0.1gal/h), or 0.6l/h with the ac on (0.16gal/hr).

I'm surprised you get almost 9 times more fuel consumption at idle!
Then again, the forester has a 2 to 2.5 liter engine. The larger the engine, the higher the consumption.

Personally I wouldn't bother with start stop technology.
The engine wears out most during startup procedure, according to Shouty Kilmer:



Also, a lot of the 3.6 minutes start stop, is from the entire trip.
Many times, cars stop their engines to start them well within 1 minute. Sometimes stopping the engine, only to start it again within seconds, because that's how traffic goes.

I have never ever waited somewhere for 3.6 minutes (save for a railroad crossing with a long train passing at slow speeds, where I do turn off the engine).

The engine wear, starter wear, battery wear...
Not only the items breaking, but just one time charging labor, nullifies the savings you get on fuel.

Last edited by ProDigit; 09-11-2018 at 08:23 PM..
  Reply With Quote
Old 09-11-2018, 11:45 PM   #9 (permalink)
EcoModding flying lizard
 
Daschicken's Avatar
 
Join Date: May 2012
Location: Georgia
Posts: 743

Cibbie - '88 Honda CBR 250R
Motorcycle
90 day: 48.49 mpg (US)

Rarity - '06 Honda Accord EX V6
Team Honda
90 day: 29.88 mpg (US)

Baby viff - '86 Honda VFR 400R
Motorcycle
90 day: 42.15 mpg (US)

Latios - '08 Suzuki SV650SF
Motorcycle
90 day: 64.56 mpg (US)

Mazda 3 - '14 Mazda 3 i Sport
90 day: 43.25 mpg (US)
Thanks: 618
Thanked 261 Times in 174 Posts
Thanks for posting this, I probably wouldn't have seen it otherwise!

I also answered a butt-load of comments regarding fuel economy on that video...
__________________
-Kaze o tatakaimasen-

Best trip in V6: 52.0
Best tank in V6: 46.0
Best tank in Mazda: 49.9
Best tank in CBR: 61.3
Best tank in SV: 83.9

Quote:
Originally Posted by MetroMPG View Post
You can lead a fashion-conscious horse to unusual-looking water...

  Reply With Quote
Old 09-12-2018, 08:32 AM   #10 (permalink)
Cyborg ECU
 
California98Civic's Avatar
 
Join Date: Mar 2011
Location: Coastal Southern California
Posts: 6,299

Black and Green - '98 Honda Civic DX Coupe
Team Honda
90 day: 66.42 mpg (US)

Black and Red - '00 Nashbar Custom built eBike
90 day: 3671.43 mpg (US)
Thanks: 2,373
Thanked 2,172 Times in 1,469 Posts
Quote:
Originally Posted by ProDigit View Post
The engine wear, starter wear, battery wear...
Not only the items breaking, but just one time charging labor, nullifies the savings you get on fuel.
I wouldn't call what Shouty's fuel economy discussion in this video "calculations"... it's more like he decided to knock stop/start technology and then just made the numbers fit. I don't like Shouty's videos when he gets into questions like this. He seems mostly to fire from the hip when it comes to anything fuel economy or engineering related. Where I like him is on questions of repair and maintanence.

The Engineering Explained vid is considerably more persuasive as far as calculations.

Also, I am driving a 1998 Civic that I bought in June 2001. It has 260,000 miles and still has the same rods and bearings and piston rings... same 1998 starter. But for the last 90,000 miles I have been stop/starting it maybe 10 times a day.

Just one person's experience... but I think the hardware is a lot more durable that he is claiming.

__________________
See my car's mod & maintenance thread and my electric bicycle's thread for ongoing projects. I will rebuild Black and Green over decades as parts die, until it becomes a different car of roughly the same shape and color. My minimum fuel economy goal is 55 mpg while averaging posted speed limits. I generally top 60 mpg. See also my Honda manual transmission specs thread.



  Reply With Quote
The Following 3 Users Say Thank You to California98Civic For This Useful Post:
Daox (09-12-2018), Gasoline Fumes (09-12-2018), Xist (09-12-2018)
Reply  Post New Thread


Thread Tools




Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com