Question about hills - Page 3 - Fuelly Forums

Android Users - Coming Soon! - Migrating from aCar 4.8 to 5.0

Reply
 
Thread Tools Display Modes
 
Old 07-12-2008, 07:50 PM   #21
Registered Member
 
thornburg's Avatar
 
Join Date: Jun 2008
Posts: 162
Country: United States
Quote:
Originally Posted by Ford Man View Post
After installing a vacuum gauge in my '88 Escort I have found that it is much better to let completely off the gas going down hill than to maintain the same or less acceleration.
Are you accounting for the greater fuel required to go up the other side because you were going slower? Or are we only talking about lone hills (which are always up first then down, without another up after the down)?

I'd be curious to see some multi-run testing done by someone with one of those computer data-logging setups, testing various methods of going up & down the same hills over and over again. Of course, it would be ever better to get several sets of data (for example, DFCO behavior plays a big role in what the "best" method is).
__________________

__________________
thornburg is offline   Reply With Quote
Old 07-12-2008, 08:16 PM   #22
Registered Member
 
Join Date: May 2008
Posts: 85
Country: United States
I aim for speed limit + 9 at the bottom of the hill and hold the LOD on the ScanGauge as high as I can. Last night I saw it hold at 99 before it finally downshifted. When it downshifts, instantaneous mileage is cut almost in half. Everything about driving the Escape around town is getting it into the highest gear possible.

The hard part is starting off uphill. There's nothing to to do but punch it to get enough speed to let it upshift. Otherwise I'm spinning uphill with mileage in single digits.
__________________

lowbridescape is offline   Reply With Quote
Old 07-13-2008, 05:14 AM   #23
Registered Member
 
theholycow's Avatar
 
Join Date: Apr 2008
Posts: 6,624
Country: United States
Send a message via ICQ to theholycow Send a message via AIM to theholycow Send a message via MSN to theholycow Send a message via Yahoo to theholycow
Quote:
Originally Posted by thornburg View Post
I'd be curious to see some multi-run testing done by someone with one of those computer data-logging setups, testing various methods of going up & down the same hills over and over again. Of course, it would be ever better to get several sets of data (for example, DFCO behavior plays a big role in what the "best" method is).
It would probably also suffice to use average mileage over a whole tank of fuel, one tank with one strategy, one tank with the other...
__________________
This sig may return, some day.
theholycow is offline   Reply With Quote
Old 07-13-2008, 05:33 AM   #24
Senior Member
 
Join Date: Mar 2011
Posts: 446
Country: United States
Location: Charlotte nc
OK I'll step up on this one ....
We are dealing with a turbocharged car here. (boost=lots of fuel) the idea here is to keep out of the boost I think you have been doing things right if you can accelerate down the hill staying out of boost (good) and if this keeps you out of the boost going up the other side then this works. Again BOOST= bad FE
Philip1 is offline   Reply With Quote
Old 07-13-2008, 06:50 PM   #25
Registered Member
 
Join Date: Apr 2008
Posts: 174
Country: United States
He needs a electronic boost controller, then he can turn the boost off when he wants and drive with out it. On any grade i try to put it in neutral or eoc and get as far up as i can then kick it in to the top if i slow to much. Lately thought the traffic has been so sparse i can at times slow to 40mph while p&g on the freeways. My how my thinking has changed, i look for trucks now to draft. In the past they just annoyed me to now end. This works well for overpasses and bridges. Eoc with a truck in front is the best.
1cheap1 is offline   Reply With Quote
Old 07-14-2008, 07:25 AM   #26
Registered Member
 
Join Date: Nov 2007
Posts: 1,460
Country: United States
Location: north east PA
Quote:
Originally Posted by 67 Satellite View Post
I usually just keep my right foot steady and let the car pick up speed down the hill then let it slow slightly on the up hill side.The speeds are kept within reason though and there aren't that many big hills around here anyway.I try to keep it less than 10 m.p.h over the limit and 5 m.p.h. under.
This is refered to as driving with load (DWL). Keeping the engine at a set load or throttle position is more efficient than varying it, outside of pulse and glide that is.
trollbait is offline   Reply With Quote
Old 07-14-2008, 12:52 PM   #27
Registered Member
 
Join Date: May 2008
Posts: 9
Country: United States
What about cruise control

Talking about hills, what about cruise control? Should I disengage the cruise control? We don't really have "hills" in coastal Texas, unless you call the overpass "hills".
WhitePolarBear is offline   Reply With Quote
Old 07-14-2008, 03:14 PM   #28
Registered Member
 
KARR's Avatar
 
Join Date: Sep 2008
Posts: 73
Country: Portugal
Location: Algarve
Quote:
Originally Posted by R.I.D.E. View Post
Your total energy use, will be lowest if you avoid speeds above your desired average. This is becasue of the exponentially greater aerodynamic drag at higher speeds.

Of course if your speed increases as you coast down the hill that additional speed costs you no additional fuel. The question is the risk of a traffic violation as well as your personal safety.

Note (coasting by my definition is always in neutral)

Most of the hills here are very small grades, so there is no possibility of dangerous speeds.

In a perfect scenario, your hill would be the perfect grade and you could maintain the same speed regardless of whether you were going uphill or downhill.

Remember aero drag is by far the greatest source of energy losses at high speeds, close to 2/3 at 65 MPH.

That is why my strategy is to try to maintain the same speed.

regards
gary
I've done a search trying to find the exponential dependence of drag with speed but I didn't find it. The only formula I know is



Can you tell the formula of the exponential dependence please?
KARR is offline   Reply With Quote
Old 07-14-2008, 05:37 PM   #29
Registered Member
 
Join Date: May 2008
Posts: 85
Country: United States
It's the V squared part. Drag is proportional to velocity squared.
lowbridescape is offline   Reply With Quote
Old 07-15-2008, 07:35 AM   #30
Registered Member
 
Join Date: Nov 2007
Posts: 1,460
Country: United States
Location: north east PA
Quote:
Originally Posted by WhitePolarBear View Post
Talking about hills, what about cruise control? Should I disengage the cruise control? We don't really have "hills" in coastal Texas, unless you call the overpass "hills".
On flat roads, using cruise control is DWL. My parents live in such an area of NC, and using cruise will usually net above EPA. It won't be the numbers using extreme hypermiling methods, but it's easy and reliable. On hilly terrain the cruise control can hurt milage. It tends to be more aggressive trying to maintain speed, and won't take advantage of downhill coasts.
__________________

trollbait is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Hyundai Active Eco System DurhamRich General Fuel Topics 4 05-25-2012 01:46 PM
energy saving light bulbs Project84 General Discussion (Off-Topic) 15 01-18-2008 08:12 AM
Assembled EFIE GasSavers_andyj For Sale 0 11-24-2007 05:49 PM
Low Flow Shower head kickflipjr General Discussion (Off-Topic) 28 07-14-2007 08:26 AM
Arggg.... Hooray For Proprietary Fluids! trebuchet03 General Discussion (Off-Topic) 2 05-08-2007 11:03 AM

Powered by vBadvanced CMPS v3.2.3


All times are GMT -8. The time now is 09:54 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.