EVcast #125: Weekly EVcast: Hypermiling!

I love the hypermiling tips guys, thanks for that. Some of them I can use in my EV too. Thanks again.

One thing they could have mentioned when suggesting ways to deal with agressive drivers is by putting a sticker on the back of their car saying something like, "HYPERMILING IN PROGRESS"

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Great show on Hypermiling guys!  And very good job putting this together Ryan. I don't jack-rabbit start and stop, but I do try to slide ahead of everyone I can- that's my game;-)  But, frankly, it does make me a bit grumpy driving sometimes (or so my kids point out)- I hate getting caught behind what I call the 'slacker drivers' who leave huge gaps in front of them- and then I fume while car after car cuts in front of them while I am stuck behind.  Rationally, I know that the time lost is not much- but emotionally I am grumbling 'knucklehead...idiot...moron!' to myself. And then I start dialoguing with myself.  The voices.  Not good.

I guess the best thing to take from those who are hypermilers, is to remember that this is the extreme, the cutting edge. We should never be cutting off our engine, or driving so slow as to cause a large bottleneck in traffic.  But, there is much to learn in some easy techniques, that may help us not only incease our efficiency- which will help in EV driving as well, to extend battery range, as Gav mentioned above- but also in learning to drive with a calmer attitude.  One of the slogan campaigns in Texas when I was a kid was to 'drive friendly-' we have gotten away from this attitude, and it is not a bad one to adhere to.

Anyway, for those interested, you can see Wayne' site at:  http://www.cleanmpg.com/

And my fellow Texan, Dan's site at:  http://www.106mpg.com/106/

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EVcast#124 was a meaty show on hypermiling.  I forgot Wayne was the “godfather of acronyms” as well as the “godfather of hypermiling”. Yikes. FAS, PP, RR, P&G! Hope the intellectual challenge of remembering what all the letters mean doesn’t dissuade people from applying one or more of the driving techniques.

I have two comments on the show. 

Number 1, the use of an “instantaneous” MPG gauge like the aftermarket product ScangaugeII nets you an outstanding return on investment. These add-on devices only cost about $150. Lacking the feedback of such a device has you driving “blind” as far as fuel economy is concerned. I consider myself a fuel frugal driver if not a hypermiler and I was amazed at the fuel economy improvement I got after I installed one of these devices in my own car and started paying attention to it. The ammeter in my old Gizmo EV served the same purpose. It alerted me to the real effect of my own right foot on my electric “fuel” mileage.

Number 2, there was one statement Dan made that has been scratching my head. I’m skeptical about his advice to fill up at the same station every time you buy fuel because using different gas from different stations sends your ECU into a so-called “calibration mode” and this calibration mode diminishes your fuel economy. The way I heard it in the podcast, he was saying your fuel economy is going to be better if you ALWAYS fuel up at the ABC station on the corner instead of switching to DEF, then XYZ, then back to ABC for fuel.

This seems a bit far-fetched to me. Here’s a couple of reasons why.

1. ECU’s adjust fuel/air mixture, ignition timing and other variables based on data gathered from several sensors. ECU’s respond with adjustments many, many times per second in NORMAL OPERATION. So what is this so-called “calibration mode” Dan is warning us about? If this mode does exist, I have a hard time believing the ECU spends even 1 second doing this “calibration mode” let alone enough seconds to harm fuel economy significantly

2. Dan’s advice is based on the assumption that the fuel at ABC station is consistent from week to week and therefore does NOT cause your car or truck’s ECU to flip into this less-efficient “calibration mode”. Gasoline and diesel fuel from a given station is NOT consistent. It is a generally accepted fact that batches of gasoline and diesel fuel vary somewhat depending upon a dizzying array of factors such as the specific type of crude oil used to refine the fuel. Bear in mind that fuel delivered to stations of different companies is typically drawn from the same bulk fuel terminal and varies only in the specific additive package added to the fuel to make it “ABC’s” fuel vs. “DEF’s” fuel.

In light of this, it’s wishful thinking to believe that the fuel at the ABC station on the corner does not vary week to week.

Additionally, despite company claims to the contrary, I’m not aware of any controlled studies that have shown a discernible difference in fuel economy from brand to brand, ECU “calibration mode” effects or no.

3. He mentioned “adjusting to the proportion of alcohol in the fuel” implying it is that adjustment which is responsible for a lower fuel economy. Perhaps he was speaking of a “flex-fuel” vehicle designed to use E85. The ECU in such a vehicle is able to detect the proportion of fuel in the tank that is alcohol and adjust to the different burning characteristics of the fuel. That is, a tank half filled with E85 that is topped up with 100% unleaded regular ends up with something like E40. The E40 burns differently than E85 and differently than 100% unleaded regular gasoline. Again, I’m hard pressed to believe that modern ECU’s, even those in a flex-fuel vehicle get stuck in this “calibration mode” enough to screw up fuel economy significantly.

4. Finally, let’s assume Dan is right and “calibration mode” does exist and have a negative effect on fuel mileage. How much does it affect the mileage? 5% 10% Does that warrant sticking with same fuel if you can save 20% at another station?

I’d be curious to see if there is some independent lab testing that demonstrates the phenomenon he is referring to. Heck, it’s a big world. I could be dead wrong. I’d just like to see the numbers that back up what Dan was asserting.

Ray

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