Well ..

It could be a headstart from the mafia ..

Or Pulse & Glide: where pulse refers to engine use at it's efficient power demand range, and glide is no arrows on the Prius below 40ish mph, and engine off for other cars. The 40ish mph Prius limit is a consequence of that cars design requiring engine spin above that velocity, and attendant 1.5 kW energy drain -- even if no arrows show up on the MFD.

 

Hi Hot_Georgia_2004:

___I PM’ed you 2X’s to meet in chat to discuss it. Right now Lakedude is the HCH w/ a stick guinea pig and Tbaleno is the CVT guy. Both have seen an excellent improvement although it fits their particular commutes better then yours or mine

___The next time you are on, we can go through some of the details in chat …

___Good Luck

___Wayne R. Gerdes
___Waynegerdes@earthlink.net

 

Russian Hypermilers (1960s?)
I recall many years ago reading a description of Russian driving techniques. Because of the cost of gas, drivers would get up to speed, turn off the ignition and coast out of gear till just barely enough speed to restart by putting it back in gear. These were certainly not hybrids. So, I guess this would qualify as an early version of pulse and glide.
More recently (1996) in the former Soviet central Asia, rural roads are so rough that drivers wander all over the road looking for the smoothest part. Sometimes drivers going in opposite directions would have differing opinions on what was the smoothest part and pass with each on the wrong side.
--Walter
PS The dedication of the hypermilers here is amazing. In particular, krausdb had a 900 mile tank not going over 45 mph! I think I'll have to start meditating or something to achieve such patience. Also, Lakedude (and others) driving in 98+ humid degrees with no AC earns them sainthood; I wimp out at about 80 degrees.

 

Hi Walter,

Interesting story !

I have no idea what is really true -- but I remember as a child stuck in Los Angeles CA gridlock being told by my mother that idle was less wasteful of gas than reignition. I would also think the wear on the engine would be something to consider .. at least in ICE only cars.

P&G in a Prius is easy and fun -- I'd do it even without MPG benefits for the joy of silent travel. Having to actually turn the ignition off, though, is a hack as far as I am concerned. Interesting, and proof of concept, but not something I would do or recommended.

 

What would you say is the ideal useful speed for P&G? I know it's not going to work for me on the freeway because it takes forever to accellerate from 60 to 70mph in 5th gear. Like.. maybe 25 seconds or something? I guess I'd have to time it to be sure, but once I push in the clutch and let it free coast, it only takes maybe 10-12 seconds to fall back down to 60mph again.

I think on suburban streets maybe it would be different. The coast rate is greatly improved once you're below 50mph or so, so perhaps on a 45mph road if would work well to P&G from 40 to 50mph? Shutting the engine off completely isn't really an option at this time of year because then you lose the A/C too. Still, cruising at 50mph, the car is drawing around 1.1 gallons per hour. Push the clutch in and let it idle at 800rpm and consumption drops to around 0.2gph. Maybe I'll have to go out in a little bit for some back to back testing with the ScanGauge to see if I can determine if it's beneficial over a long stretch of road. Come to think of it, there's a nice 2-mile stretch of road with no stops about 8 or 9 miles from my house that usually has no cars on it at all since it leads from nowhere in particular to nowhere in general. Hmm!

 

Hi AZCivic:

___P&G is not conducive to high FE at highway speeds. It is in a more leisurely cruise around town or in the suburbs in my rather limited experience with it.

___Forcing an Autostop at speed drops out you’re A/C but it does not drop out your fan. A minute or two is not that long for the HX’er to be drawn down to external ambient. It won’t be as comfortable as just letting her run but that is up to you … Anytime you can reduce fuel consumption is a good thing but no fuel consumption is always better imho

___EricGo, Forced autostops and reboots are a work around and are not natural by any means. Neither is watching the energy screen to maintain a proper Glide nor the pulse at a particular optimized rate of acceleration. The best OEM solution to date imho is the Insight’s ICE drop out at 19 mph and below when the clutch is engaged. The best FE optimization at a higher speeds up to 41 mph is the Prius II’s using P&G. I have never driven or read enough about the GM EV-1 but I wonder if Regen was harsh as soon as the accelerator was let off or did it come to play ONLY after the brakes were touched? I would hope the latter because this is the way to save Fuel/Electricity over the long haul imho.

___Good Luck

___Wayne R. Gerdes
___Waynegerdes@earthlink.net

 

Would P&G really help with a full electric? I was under the impression that it was efficient simply on account of the fact gasoline engines have the highest volumetric efficiency at ambient manifold pressure since they don't do any negative work creating vacuum. Since an all electric has no such mechanical inefficiency, I would think it's FE would be the same or worse with P&G than a steady speed.

Anyway, I did a bunch of tests this afternoon, but was too tired and worn out by the time I finished the last of the ones I wanted to do and I never even attempted P&G except on the drive home.. it seems promising, but once I started to think about it, I'm still not entirely sure it will help on vehicles that are capable of lean burn since you won't be in lean burn during the accelleration phase of P&G.

 

Hi AZCivic:

___Look up the Super FE challenges when you get the time. They use a type of P&G technique in these science experiments to achieve > 10,000 mpg. Yes, it will work in an EV as well as long as regen can be held at bay during the Glide or Coast phase.

___About P&G in a lean-burn equipped hybrid … It has already been proven to increase FE in (2) Lean-Burn equipped HCH’s to date. You can maintain lean-burn during accelerations in the Insight but I do not know about the rest. No, I do. The HCH can as well in my short time behind the wheel of Tbaleno’s. The AH does not have lean burn so it’s a moot point with regards to Lean-Burn in it. I do not know about the Civic HX though?

___Good Luck

___Wayne R. Gerdes
___Waynegerdes@earthlink.net

 

Yep, the HX has lean burn. That was the big selling point of the HX; better fuel economy than the DX/LX with more power than those models too. The only real problem is that there's no lean-burn indicator or anything so I can never really be sure when I'm in lean burn mode. I'll give it a shot though, it sounds like it's a proven technique, so I should try to find some way to make use of it. Thanks for the info! Maybe by this fall when the weather's in that sweet spot of cool enough to not use A/C but warm enough to ensure quick engine warm-up, I'll find a way to break 50mpg for a round-trip drive somewhere. My current record is 47.0mpg for a 200 mile trip, so it shouldn't take too much to break the record.

Somewhat OT: I did some searching for the Super FE challenges, and found the SAE Supermileage competition. Looks like 2005's winner achieve 1836mpg in a 77 pound, 0.11cd vehicle with a 48cc fuel injected engine. The car however is TINY! Holy smokes.

 

AZ, cool pic!

Further updates:

IMC now has 152 miles on this tank with a displayed trip mileage of 83.6 mpg! This seems to be a sustainable figure. The mileage goes up when I go downhill twards home and back down the next day going back uphill to work. 83.6 is what the display reads at work which is the most realistic. I'll post a pic when I get home.

Who wants video?