Just for kicks today, I cut and pasted (wonder if there's a way to export the data) my mileage record into an Excel spreadsheet and ran a correlation between number of minutes/ride and mpg. The correlation was +.65, a fairly strong correlation.

Of course, I'm not controlling for any other variables, so I'm sure that A/C, road grade, and many other variables are equally if not more important, but I am curious if anyone has done more rigorous statistical analyses on the variables they've measured that may relate to fuel economy for their Civic Hybrid.

Aneil

 

Another spreadsheet geek!

There are SO many factors that effect FE that we can't factor that I don't know how you could put together a meaningful analysis though. Take my ride home tonight for instance--it seemed like I hit EVERY stop light on red. Although, I did get the best milage I've had on the round trip which is probably due to the warming temperatures. Or maybe I'm learning my new commute and can hypermile it better. Too many factors that are too difficult to quantify...

I would like to use a GPS to measure altitude gain/loss sometime to figure out the effect it has, but we don't have any flat roads to use as a control.

 

I've found that by far, temperature plays the biggest role in my FE, followed by weather and the driver. It's actually rather curious... if the temperature was above my lifetime average, the tank was better than average, and likewise, below tank average temps resulted in a below average tank. So far on this one, with temps generally in the 60F range, the first 250mi of this tank has gone at 56mpg. I haven't had a tank this high since last September, when the average temp was 70F. So there's definitely something to be said for temps.

Next up, weather. In short, rain sucks. I figure it might be as much as a 5mpg penalty just pushing through all that water. Keeping your tires inflated can only do so much here. The rest is a function of how deep your tire tread is, how good it is about moving water out, and how much water there is to begin with.

Can't forget about break-in, both the car *AND* the driver. It's not uncommon to hear people reporting sudden jumps in the 3k-5k mile range as the car settles in, but driving these things isn't like driving a normal car. In a regular car, you don't have the iMPG gauge telling you whether you're being a hippie or a gulper, nor do you have the boost/regen meter to get an idea of whether you're stomping the gas or coasting along. What non-hybrid car can shut the valves off entirely and just roll along on electric when you get good at reading the two of them combined and feathering foot pressue?

 

Yep - both temp and trip time are significant positive factors on mpg.

I did do some cut/pasting of several of the 50+ tank vehicles in the database into Minitab and virtually all had positive effect of temperature, but many had little effect from trip time. Since I am a newbie I dont know yet how to post images to these or I would share...

 

I'm starting to see about a 10% improvement (50mpg vs. 45mpg on one of my "barometer" city drives) after hitting 3k+ miles on the car. I'm sure that it's both the car and the driver, but mostly the car. Other Japanese cars I've owned seem to hit their plataues about 15k so I'm hopeful to see continued improvement.

My Outback has an iMPG gauge (no electric/battery of course though) but I'm coming to the conclusion that hypermiling that car is a "waste" for me. I get the same 10% improvement when I drive very conservatively (23mpg hypermiling vs 21mpg my normal driving and 19mpg 2005 city EPA). That 2mpg (10%) isn't nearly as compelling as the 5-6mpg (10%) improvment that hypermiling in the HCH gets. Silly isn't it?

 

I hate to disagree with you in my first post on the site, but... Don't give up your efforts with your Outback! I guess I'm a bit of a spreadsheet geek too, 'cuz I whipped one up using the data from your post. Over a 1000 mile trip, hypermiling your Outback and getting 23 MPG instead of 21 MPG you will save 4.14 gallons of gas. and at $2.5 per gallon you'll save $10.35.

Hypermiling your hybrid from 40 MPG to 46 MPG over that same 1000 mile trip will save you only 3.26 gallons of gas, and only $8.15.

The 2 MPG increase you get from your Outback is actually making a larger difference in gallons of gas used (and that's what it's all about, right?) than massaging another 6 MPG out of your hybrid.

Realistically "hypermiling" works BEST on the LEAST efficient vehicles. If you take the least fuel efficient vehicle, currently the Lamborghini L-147/148 Murcielago, and ease up just a bit to inch it one single mile per gallon from 9 MPG to 10, you will save over 11 gallons on a 1000 mile trip. to save the same fuel with your Civic you would have to hypermile the sucker from 40 to 72 MPG!

If anything, you should relax a little while you're driving your already very efficient Honda, and pay even more attention to your habits when you're driving your less efficient Subaru Outback.

 

The magic of math once again!
Excellent first post, Rockmonkey! And, welcome to GreenHybrid.

 

Rock's already covered the math that says squeezing another 2mpg out of the Subie is more "useful" from a save the world/save your wallet stanpoint than another 6mpg out of our Civics, but I also wanted to point out that in a car like that, getting any improvement is worthy of celebration. Remember that in the Outback, you've got a couple things working against you:
- No IMA/HSD style drive train, thus no energy re-capture
- All-Wheel Drive, all the time. It's great in the middle of winter, on muddy roads, and stuff like that, but when you're driving down the freeway in the middle of August, AWD is doing nothing but sucking extra gas

FWIW, I "hypermiled" a rental Chrysler T&C w/ in-mirror mpg gauge last October. The rental company said to expect maybe 18mpg, and the mirror was at 16mpg/4k miles when I got it. Reset the thing, and over the week/500mi I drove it, it averaged 26

 

Good point. And the Outback takes premium with the turbo so the difference would actually be even more of a relative financial benefit than your post would suggest. The difference is that I can get 50mpg hypermiling the HCH on my commute instead of 46mpg in your example.

Therein lies the problem. I thoroughly enjoy driving the HCH from a fuel efficiency/get the best score you can standpoint, but it isn't a "driver's car". The Outback just encourages you to go deep with the pedal when the boost builds and throws you back into your seat.


I thouroughly believe that no analytical person should be allowed to drive a hybrid . It's too much fun!!!