Planning to make a regression model... anyone else? - Fuelly Forums

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

Reply
 
Thread Tools Display Modes
 
Old 03-19-2009, 04:21 AM   #1
Site Team
 
Join Date: Dec 2006
Posts: 656
Country: United States
Planning to make a regression model... anyone else?

Over the past few days I've been contemplating how much average speed affects gas mileage. So I've decided to conduct an experiment.

Turns out that my GPS has a feature that allows me to calculate moving average MPH over a given period. So from now on, every time I fill my tank I will record the miles, MPG, and the average speed for that tank. After I have enough data (probably 30 - 40 tanks), I'll make a linear regression model to see what the effect of average speed is on MPG.

(I know that MPG is not exactly linearly related to speed, but I'm just gonna force the data)

Anyone else want to do something like this? I'd be especially interested in getting a cross-section of different types of vehicles, including an SUV/pickup (F250, Suburban, that kind of thing) if there is anyone here who has one. I'll do the calculations, I just need you to do the record keeping.

(Of course the data would be messed up if you make any vehicle modifications, etc., so don't plan on making any changes. And obviously I'd need some way for you to calculate a moving average speed.)

-Bob C.
__________________

__________________
Think you are saving gas? Prove it by starting a Gas Log, then conduct a proper experiment.
bobc455 is offline   Reply With Quote
Old 03-19-2009, 05:25 AM   #2
Registered Member
 
Join Date: Mar 2009
Posts: 1,139
Country: United States
Wouldn't a ScanGauge or similar system allow you to examine speed vs mpg more directly? Or are you thinking this would be more accurate?
__________________

__________________


Main Entry: co de pen dence - see codependency
co de pen den cy
Pronunciation: \kō-di-ˈpen-dən(t)-sē\
Function: noun
Date: 1979

: a psychological condition or a relationship in which a person is controlled or manipulated by another who is affected with a pathological condition (as an addiction to alcohol or heroin) ; broadly : dependence on the needs of or control by another
GasSavers_maximilian is offline   Reply With Quote
Old 03-19-2009, 09:15 AM   #3
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
That sounds like a whole lot of work.

You'll have to alternate tanks at low and high average speed to avoid interference from seasonal temperature/weather changes.
__________________
This sig may return, some day.
theholycow is offline   Reply With Quote
Old 03-19-2009, 12:16 PM   #4
Site Team
 
Join Date: Dec 2006
Posts: 656
Country: United States
I don't have a scangauge so I can't comment about what it can (or can't) do. If it can do fancy calculations like average speed per tank and whatnot, that would be cool. I'm not keen on instantaneous readings, I don't think they are accurate enough.

HC, I have a few different routes I can take to work (typical commute is 1 hour each direction) with varying speeds and distance, and when you mix in other types of driving there should be enough variability to cover a decent range of average speeds. The regression calculation itself is fairly simple (for me).

-BC
__________________
Think you are saving gas? Prove it by starting a Gas Log, then conduct a proper experiment.
bobc455 is offline   Reply With Quote
Old 03-19-2009, 12:32 PM   #5
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
ScanGauge does indeed provide average [speed, MPG, and some others I don't remember] per tank, per day, and per trip.

I've seen one person put average speed in their gaslog but I don't remember who.
__________________
This sig may return, some day.
theholycow is offline   Reply With Quote
Old 03-19-2009, 12:41 PM   #6
Registered Member
 
Join Date: Mar 2009
Posts: 1,139
Country: United States
When I had a Scangauge II I used the trip cost feature (enter the price/gallon) to figure out what was the fastest way to the grocery store (two ways, about a 45 minute trip). One was a mile shorter, but the terrain varied a lot making it less than obvious which would be best. Of course I had to consider both ways, so it was four separate measurements. The shorter route won for both directions and was cheaper by about 25 cents/trip (at the nearly $4/gallon gas price at the time).
__________________


Main Entry: co de pen dence - see codependency
co de pen den cy
Pronunciation: \kō-di-ˈpen-dən(t)-sē\
Function: noun
Date: 1979

: a psychological condition or a relationship in which a person is controlled or manipulated by another who is affected with a pathological condition (as an addiction to alcohol or heroin) ; broadly : dependence on the needs of or control by another
GasSavers_maximilian is offline   Reply With Quote
Old 03-20-2009, 01:32 PM   #7
Registered Member
 
bowtieguy's Avatar
 
Join Date: Oct 2008
Posts: 1,873
Country: United States
Location: orlando, florida
Quote:
Originally Posted by theholycow View Post
I've seen one person put average speed in their gaslog but I don't remember who.
i may not be the only one, but i do log avg mph when i remember. just my dd however...

http://www.gassavers.org/garage/viewgaslog/1239
bowtieguy is offline   Reply With Quote
Old 03-20-2009, 02:44 PM   #8
Registered Member
 
Join Date: Apr 2008
Posts: 1,259
Country: United States
Location: wiliamsburg virigina
Mine works out to;

80MPG at 40 MPH
70MPG at 50 MPH
62MPG at 60 MPH
54MPG at 70 MPH

regards
gary
__________________
R.I.D.E. is offline   Reply With Quote
Old 03-22-2009, 07:31 AM   #9
Registered Member
 
Jetta90GL's Avatar
 
Join Date: Mar 2008
Posts: 75
Country: United States
I log avg speed on my F250. I have an hour meter installed that turns on with the ignition 12 volt source. This way I am also averaging the time I sit at stop signs idling. It isn't all that easy to figure out what average is best. It mainly shows me how much city driving I've been doing. If I had to make a guess, about 46 mph would be my best average speed, since that is when my overdrive finally kicks in.
__________________

Jetta90GL is offline   Reply With Quote
Old 04-04-2009, 03:58 PM   #10
Registered Member
 
Join Date: Aug 2006
Posts: 34
Country: United States
Why just do linear regression fitting? There are a lot of other stastical models that should be able to give you a better model. You are going to need at least "something quadratic" or possibly cubic to model any remaining third-order effects.
__________________

parasonic 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
First post, first project Detroit getting it done Aerodynamics 1 07-22-2008 06:58 AM
Video: Saab 9000 gassaving GasSavers_elg General Fuel Topics 2 02-18-2008 11:56 AM
Got a funny message from crxMPG today SVOboy General Fuel Topics 11 10-13-2007 06:37 PM
Doh! Crystal General Fuel Topics 2 06-29-2007 01:34 PM
Mph Caps billynjoanna General Fuel Topics 2 06-10-2007 12:38 PM

Powered by vBadvanced CMPS v3.2.3


All times are GMT -8. The time now is 01:07 PM.


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