Temperature Effects

[Diesel_Dave]

I was number crunching on my daily log data and thought folks might find this interesting. I plotted 80 days (160 commutes) worth of mileage and ambient temperature data:


Mileage goes to the left axis, temperature to the right.

Like everyone else, I can't wait for it to warm back up!

[JRMichler]

Try cross plotting temperature against gas mileage. Temperature on the horizontal axis and gas mileage on the vertical axis.

[Diesel_Dave]

Originally Posted by JRMichler

Try cross plotting temperature against gas mileage. Temperature on the horizontal axis and gas mileage on the vertical axis.

Okay, here you go:


40 deg F change results in about a 20% change in mileage. So mileage changes 1% for every 2 deg change. That's pretty significant.

[CigaR007]

Awesome !

[oil pan 4]

Nice this very good to see.

[slowmover]

Nicely done. What were the dates of the 80-day period, and what is the date of the first and last frost for your locale? Any other relevant climate data by which to make comparisons? (or, do dawn/dusk considerations play a part?)

(For us the potential frost period is Nov 23 - Mar 9; with some as years [as this one] no frost at all; January thru first week of February constitute winter"; maybe only 10-days). A/C use is the bugabear for FE.

You "commuters" can certainly have good data to work with in re set conditions of place and time over the year.

.

[gone-ot]

Now, *that's* the kind of number-crunching I like to 'see' -- show me the graphics (ha,ha)!

You've just documented & published the "Diesel Dave's TEMP Rule-of-Thumb":

"... -1% FE change per each -2ºF temp change...and...+1% FE change per each +2ºF temp change."

[mcrews]

Dave,
how long is the comute?
Does the vehicle start uotside (so the temp has settled in overnite)
or is it in the garage?

[Diesel_Dave]

Originally Posted by slowmover

Nicely done. What were the dates of the 80-day period, and what is the date of the first and last frost for your locale? Any other relevant climate data by which to make comparisons? (or, do dawn/dusk considerations play a part?)

(For us the potential frost period is Nov 23 - Mar 9; with some as years [as this one] no frost at all; January thru first week of February constitute winter"; maybe only 10-days). A/C use is the bugabear for FE.

You "commuters" can certainly have good data to work with in re set conditions of place and time over the year.

.

It's from Oct-10 unil Feb-15. It's 80 commuting days--not 80 days. Dates of potential first/last frost are before and after this time. I've had a couple mornings down below 15 deg F and those have been hard on the mileage. The "3-day average Temp" is the average of 3 mornings and 3 evenings, so mornings and evenings are grouped together. Dawn/dusk shouldn't play much of a role because pretty much all of it during that time period would have been when I driving it's still dark enough to have the lights on. Only now, in mid-Feb, is it getting light enough that I can have my lights off much.

[Diesel_Dave]

Originally Posted by Old Tele man

You've just documented & published the "Diesel Dave's TEMP Rule-of-Thumb":

"... -1% FE change per each -2ºF temp change...and...+1% FE change per each +2ºF temp change."

I just realized that if you do it in Celsius it would be neater--basically 1 deg = 1% change.