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

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 04-18-2012, 05:56 AM   #81 (permalink)
Master EcoModder
 
IamIan's Avatar
 
Join Date: Dec 2010
Location: RI
Posts: 667
Thanks: 366
Thanked 214 Times in 131 Posts
Quote:
Originally Posted by jtbo View Post
at steady speed 26% efficiency put into calculator is giving correct results.
Well at least that is a starting comparison point.

I suspect that is not the peak efficiency point ... on a BSFC chart ~26% works out to around ~300 g / kwh ... There are many ICE's including Gasoline ICEs that do significantly better than that ... so While that might be a fair estimation of one point on the BSFC ... I do suspect it is not the peak efficiency point.

  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 04-18-2012, 04:51 PM   #82 (permalink)
Master EcoModder
 
Join Date: Jan 2012
Location: United States
Posts: 1,438

spyder2 - '00 Toyota MR2 Spyder
Thanks: 89
Thanked 267 Times in 204 Posts
Quote:
Originally Posted by IamIan View Post
Well at least that is a starting comparison point.

I suspect that is not the peak efficiency point ... on a BSFC chart ~26% works out to around ~300 g / kwh ... There are many ICE's including Gasoline ICEs that do significantly better than that ... so While that might be a fair estimation of one point on the BSFC ... I do suspect it is not the peak efficiency point.
300g/kwh is middle of the pack at "low speed" (below 70mph, because people love going 80) cruising I believe. Cars with strong acceleration and/or bad gearing will cruise in the 400s, weak cars can manage maybe a bit better than 300 at 60. Peak efficiencies on a lot of engines is getting to the high 30s(%), or around 230g/kwh, but that occurs at unreasonably high load levels for highway cruising.

As a quick example, on the upcoming FRS/BRZ/86 the automatic uses the exact same ratios as the IS250 with slightly shorter final drive, and it puts 60mph at just under 2000rpm. This leaves not much power for hills, and at 80mph you'd probably having the engine at ideal load levels for efficiency already. At 60mph the load is still something like only 30%, which may or may not land you below 300g/kwh. That car is very low and has a reasonably good coefficient of drag so that reduces the power requirement and efficiency by a bit though. I think this is realistically the longest top gear that an OEM would try to use, in terms of available excess acceleration.

Last edited by serialk11r; 04-18-2012 at 04:59 PM..
  Reply With Quote
Old 04-18-2012, 06:31 PM   #83 (permalink)
Master EcoModder
 
IamIan's Avatar
 
Join Date: Dec 2010
Location: RI
Posts: 667
Thanks: 366
Thanked 214 Times in 131 Posts
Quote:
Originally Posted by serialk11r View Post
Peak efficiencies on a lot of engines is getting to the high 30s(%), or around 230g/kwh, but that occurs at unreasonably high load levels for highway cruising.
I guess I've been spoiled ... although as you suggest the peak efficiency point is at higher loads and RPMs ... my ICE has a fairly wide ~35% efficiency point that fits well for highway cruising in a window a bit under 30% load to a bit over 80% load.
  Reply With Quote
Old 04-19-2012, 06:46 AM   #84 (permalink)
Master EcoModder
 
Join Date: Jan 2012
Location: United States
Posts: 1,438

spyder2 - '00 Toyota MR2 Spyder
Thanks: 89
Thanked 267 Times in 204 Posts
35% at 30% load is certainly superb. What can I say, you have a nice car
  Reply With Quote
Old 04-19-2012, 07:32 AM   #85 (permalink)
Master EcoModder
 
Join Date: Apr 2011
Location: Europe
Posts: 364

ZX - '97 Citroen ZX Monaco
OldContinents
90 day: 61.05 mpg (US)
Thanks: 8
Thanked 31 Times in 25 Posts
I'm driving 50mph or under, at 50mph there is 1800rpm and at hills can go as low as 1200rpm if I keep top gear, but I guess my car has shorter gearing than many US vehicles?
__________________

  Reply With Quote
Old 04-19-2012, 07:39 PM   #86 (permalink)
Master EcoModder
 
IamIan's Avatar
 
Join Date: Dec 2010
Location: RI
Posts: 667
Thanks: 366
Thanked 214 Times in 131 Posts
Quote:
Originally Posted by serialk11r View Post
35% at 30% load is certainly superb. What can I say, you have a nice car
Thanks ...I think so too.
It has spoiled me ... the ICE in it won engineering awards for every single year of the 6 years Honda built it.

Although I like it ... there was technological room for improvement back 13+ years ago when it was designed ... and there is even more technological room for improvement now ... either OEMs get to it ... or eventually if they take too many years ... eventually I'll make improvements myself.
  Reply With Quote
Old 04-21-2012, 11:50 PM   #87 (permalink)
EcoModding Newb
 
redpoint5's Avatar
 
Join Date: Aug 2010
Location: Oregon
Posts: 7,901

Acura TSX - '06 Acura TSX
90 day: 25.55 mpg (US)

Lafawnda - '01 Honda CBR600 F4i
90 day: 47.32 mpg (US)

Big Yeller - '98 Dodge Ram 2500 base
90 day: 21.82 mpg (US)

Prius Plug-in - '12 Toyota Prius Plug-in
90 day: 57.64 mpg (US)

Mazda CX-5 - '17 Mazda CX-5 Touring
90 day: 28.73 mpg (US)
Thanks: 2,606
Thanked 3,110 Times in 2,314 Posts
Quote:
Originally Posted by jtbo View Post
I'm driving 50mph or under, at 50mph there is 1800rpm and at hills can go as low as 1200rpm if I keep top gear, but I guess my car has shorter gearing than many US vehicles?
You are getting 36 rpm/mph, which is about average for most petrol cars. Don't you have a diesel? It's a bit high if so.

My TSX is 42 rpm/mph

The motorcycle, maybe 85 rpm/mph

My diesel truck with oversize tires, about 27 rpm/mph

Just bought a Jeep Liberty that does 33 rpm/mph, but it only gets 18mpg

__________________
Gas and Electric Vehicle Cost of Ownership Calculator







Give me absolute safety, or give me death!

Last edited by redpoint5; 04-22-2012 at 06:08 AM..
  Reply With Quote
Reply  Post New Thread


Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Pulse and Glide with hills Tango Charlie Hypermiling / EcoDriver's Ed 19 07-08-2013 03:53 PM
Hills vs. gently rolling hills. Tygen1 Hypermiling / EcoDriver's Ed 14 09-02-2009 12:54 PM
Swooping - technique for hills NeilBlanchard Hypermiling / EcoDriver's Ed 10 05-29-2009 01:05 PM
Big hills in a automatic lancer EcoModding Central 8 03-27-2008 05:58 PM
Rolling hills... whats the best way to drive them? hondaworkshop Hypermiling / EcoDriver's Ed 7 02-19-2008 02:49 PM



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