Friday, June 13, 2008

Hypermiling

Hypermiling, a way of increasing fuel economy, has been getting a lot of buzz in the past few weeks. I've heard stories from two morning shows, NPR, and somewhere else that I can't remember. Getting more out of each gallon is always a plus so I decided to give it a test run.

I've filled up twice since I heard the initial story and started hypermiling. On the first my fuel economy was up approx* 2 miles and on the second it was up approx 4 miles. Not super impressive result, but I only hypermile about half the time. On days where I'm on schedule or don't have a schedule I hypermile. Day's when I'm running later and have to be across town for a meeting I don't. Its somewhere around a 60/40 50/50 split.

What I've been doing:
Coasting down- when there's a hill I let gravity take its course. Instead of stepping on the brake to slow down I ease off of the gas- or just enjoy the extra speed.

Red coasting- whenever I see red (stop lights, stop signs, brakes) I take my foot off of the gas. When I need to I brake, but usually I can coast along for a while.

Keeping back- I keep a couple of car lengths between my car and the one in front of me. This lets me coast when I see red. Another way to think about it is not having to drive like the person in front of you.

Easing up- Letting the car start to roll (let up on brake) before hitting the gas. I played cards through HS physics (and somehow got an A/B) but this has something to do with the difference in effort to get tires moving from a full stop or a slow roll.

Feather feet- Lightly hitting applying pressure to the gas pedal. Manufacturers sell you on how fast you can go 0-60, but a slower start saves gas.

Slowing down- This is the hardest. According to this little chart above 60 there is a falloff in miles/gallon. The sweet spot seems to be in the 40-60 mile range.

This driving style takes though but makes sense when you get into it. Red coasting means you're not pumping in gas that you will then work against while braking. I've also found that just as I hit the stopping point for lights they tend to change.

I've read and heard more extreme things that include changing to neutral while coasting. I don't know if that would be a good idea with my automatic transmission and I feel like that's asking for an accident. Thought the tips above require thinking differently they don't make your driving dangerous.


*Approx because before I did the math in my head, stopping with a whole number, not looking at the decimals. So my last fill up could have been anywhere in the 3.4 and 4.7 miles higher.

1 comment:

L@SpillingBuckets said...

Hmm... I did most of those already... I guess I was a natural hypermiler?

I having tried riding behind semi's for the draft yet though. Interesting to see the increased gas milage.