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The Prius hypermilers use a "pulse and glide" method, where they speed up gradually to 40 mph, then coast down to 30 mph. This works well with the Prius hybrid system and maximizes economy.

Is this technique useful for the Insight? Perhaps the speed range should be greater, because of the Insight's good aerodyanmics.

Or perhaps this method doesn't work with the Insight because the ICE is always connected, and it's better to just stay at a constant speed, perhaps 35 mph?
 

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You could try it, switch to the metric display so you can see 0L/100km, it's here you are in fuel cut mode. Or alternatively there is a fuel cut relay you could wire an indicator led to. I'm thinking holding lean burn would be better overall though. I know this method worked with the Prius because at the coast point the engine is off, so everything is just sitting at idle.
 

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That's the technique used in the SAE Supermiliege competition where little one person 3 wheeled vehicles with 2 HP engines get well over 800 MPG.
 
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Hi Dougie:

___It is but you will not want not subject your Insight to a continually repetitive FAS (Forced Auto Stop). You should however consider a FAS at any time you are descending a grade as you will receive more out of that then a Prius II driver given the drag that something is causing inside the HSD while in a Glide.

___I did try this from 0 - 30 and back and you could max out the FCD at 150 + but your average speed was way to low to be of any use to anybody. If I only had my Insight knowing what I know about P&G with a 33 - 45 + mph range today :(

___Good Luck

___Wayne R. Gerdes
___[email:3e93ok8n][email protected][/email:3e93ok8n]
 

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One way pulse and glide would work well in an insight would be, as Wayne says, to use forced autostop--so that the glide is with no engine drag or charging. I'm not convinced that the repetitive starting is really so bad for the car. Assuming you stay in lean burn and don't use the IMA during the pulse phase, this is probably the ultimate. The problem is that the resulting average speed is quite low.

If you did it staying in gear, it would only work if the engine was more efficient with a relatively wide open throttle than it is at low power. In most engines that's true, but since we have lean burn, we have very high efficiency at low power. So it's unlikely to help much and might even hurt. You'd also have the problem at first that when you tried to glide you'd get charging, until the IMA pack was completely full. So you'd run with a full IMA pack, but that's bad because if you have a regen opportunity, you can't use it.

Charlie
 
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Hi Chrs:

___The following was decent enough although I wish I still had my Insight to give it a proper test ;) Even though Lean-Burn is out of the question during a pulse, her lightweight and quick acceleration would have made up for it for with some pretty spectacular and sustainable numbers in a pure P&G … Remember, a P&G in an Insight or HCH is a FAS but in a tight range band and is repetitious. I just do not know how the SoC would be taken care of given the 5-speed?

___Good Luck

___Wayne R. Gerdes
___Hunt Club Farms Landscaping Ltd.
___[email:1vnitci0][email protected][/email:1vnitci0]
 

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I don't see how this is of value.. why does this "pulse and glide" technique give good mileage? It seems like staying at a constant velocity would require less energy.
 
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Hi Foxpaw:

___I did not believe this was possible either until a daring Prius II pilot named Krousdb showed me the light about 3 months ago. When you put it all together, you begin to understand why the Prius II receives such a high EPA in the FTP75 (City) test cycle. Its ICE is only running ~ 48% of the time. The ICE is not allowing you 60 mpg but only an average of ~ 28.8 mpg of the EPA test cycles total distance and the rest is a regen based coast down/EV mode acceleration or speed maintenance. P&G just takes it to the next level w/out any regen or assist. It is only to be used where appropriate however.

___I remember when I first spoke to Rick Reese about joining us for the “Marathon – Attempt” maybe 2 + months ago and he said he did not think a Prius II was capable of 100 + mpg sustained. I showed him some real world results and bingo … Case in point; he had the highest average of all of us during the weekends extreme hypermiling drive!

___The balance and theory … If you can achieve a steady or overall, 33 mpg acceleration rate in any automobile over let us say 2.5 blocks, you only need to achieve a FAS or Glide for 5 blocks while ending at slightly above or equal to your original/initial Pulse speed to achieve 100 mpg. The kicker is that not only can you average > 33 mpg over a given distance during your pulse, you can usually glide > 2X’s the Pulse distance in the Prius II and the HCH. It doesn’t really matter if you have a 33 mpg on average Pulse, 20 mpg on average Pulse, or a 45 mpg on average Pulse, you just have to get the ICE “off” time over the correct multiple of the acceleration distance to achieve what some had thought impossible just a few months ago. Let us use a 20 mpg pulse as an example this time. With that acceleration rate, you may have only accelerated for 1.5 blocks. On the Glide, you need to achieve 5X’s the pulse distance or 6.0 blocks of coast and you have achieved 100 mpg over the 7.5 blocks. You can do the math with any number of acceleration rates and ranges but the trick is to find an optimal acceleration rate, optimal speed range to perform the technique in, and to maintain a SoC at some level without using Assist or Regen to maximum the techniques potential. If you cannot maintain the SoC, all bets are off and the technique may indeed fall apart :(

___Given the way the Prius II was designed, you can perform everything with a very self-controlled application of the accelerator including its pack SoC algorithm so that it will only allow a charge from the ICE to the pack via the MGSets at a particular acceleration rate. With the HCH and Insight, there are quite a few other gyrations involved as you know but the results speak for themselves. In the case of the HCH anyway. The above is the how and why the technique works in both the Prius and the HCH. Because of the Insight’s much lighter weight, I can see a full blown P&G achieving 125 + sustained without much thought but I do not have my Insight anymore to see what is and isn’t possible from one. The question I am really interested in however is how the SoC will behave in the 5 speed after multiple P&G cycles? I would not mind seeing the SoC of the Insight drop to 3 or 4 bars as long as it stays there with a small amount of Forced Charge during any Pulse throughout any number of P&G cycles afterwards.

___Another item … This should only be perfected on an empty road course before bringing the technique into your daily - real world - commuting realm. There are too many distractions at first and the technique has to become second nature or it is not worth performing! In terms of pack damage, it is the wild assist and regen current flows into and out of the pack that cause the damage in an Insight, HCH, or Prius II’s pack imho. That question is for another thread and for people a lot smarter then I to come up with the how’s and why’s. My own thoughts are to “Never use the pack and you will never have any problem” …

___Please look back at the Tbaleno’s HCH we P&G tested 2 days ago for the proof of concept or where the wheels meet the road. The last 2 runs averaged 100.8 mpg and we had still not fully optimized the technique plus we had two in the car with a ton of his stereo gear, spare tire, and other stuff in the trunk! We were running slightly < 50 #’s in his Bridgestone’s which certainly did not help matters either … Steady state cruise in the HCH is only worth a maximum of ~ 80 mpg from what I saw in the FCD display. With your normal traffic accel/decel losses, her maximum is back down into the 75 mpg range and that is ~ what I received out of her with 10% city and 90% highway operation over 130 + miles. Add a few FAS’ and you can get her back up to ~ 80 mpg but that is about it. You cannot achieve 100 mpg steady state driving a non-wind aided flat road in the HCH as it is impossible no matter what your speed. You can however achieve > 100 mpg sustained in the HCH under P&G because of the above and as we saw in our test runs.

___I hope that helped?

___Finally, I can see Mike D’s gears in his head whirring around and hopefully he can come up with a FAS via Mima without all the gyrations because the way to a higher FE future is with much lower ICE run times over a given distance traveled if we like it or not. Honda hasn’t figured this out yet but they will soon enough.

___Good Luck

___Wayne R. Gerdes
___Hunt Club Farms Landscaping Ltd.
___[email:1a27tvqg][email protected][/email:1a27tvqg]
 

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Foxpaw said:
I don't see how this is of value.. why does this "pulse and glide" technique give good mileage? It seems like staying at a constant velocity would require less energy.
Two ways to look at this:

1) If you were to brake and accelerate, you'd lose a lot because of not staying at a steady stpeed. But if you simply let the car coast, the only things slowing it down--air and rolling resistance--are the ones you have to work against in any case. But the bonus is that you have no engine friction during the glide part. So that's how you win.

2) It's like the question of whether you save energy setting a thermostat back when you aren't home. The answer is of course that yes, it does. http://www.washingtonpost.com/wp-dyn/co ... 00957.html

If it were really just like a thermostat, you'd only save fuel insofar as your speed would be lower, but it's better than that, because you also avoid engine friction.

Charlie
 

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chrs said:
1) If you were to brake and accelerate, you'd lose a lot because of not staying at a steady stpeed. But if you simply let the car coast, the only things slowing it down--air and rolling resistance--are the ones you have to work against in any case. But the bonus is that you have no engine friction during the glide part. So that's how you win.
Ah, this makes sense all of a sudden. I did not realize that drag within the ICE was that significant.

So then, this requires that the engine be disconnected from the drive wheels, (in neutral) and not idling in order to work? It seems there's talk of "forced auto stop" in this thread. How does one go about forcing the autostop? Fraudulent data fed into the ECU or a manual override of the fuel injectors?
 

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"Forced Autostop" is really a euphamism, since there's nothing auto about it. One simply depresses the clutch and cycles the ignition off and back on in 2 seconds to stop the engine running. There's extensive discussion of the safetly and legal issues in this thread. Not recommended without reviewing those issues.

http://www.insightcentral.net/forum/vie ... php?t=2694

Also, note that an accelerometer-corrected instantaneous MPG reading described in the tread linked below, would be very useful in helping you find the right gear, throttle position, and speed range to do the pulse in. It would give you a reading of what your MPG will be for the P&G cycle while you are pulsing.

http://www.insightcentral.net/forum/vie ... php?t=3086

Charlie
 
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Hi Chrs:

___A FAS is called a Forced Autostop because it is “Forced”, not Auto.

___In regards to safety, who decided that AS at 19 mph is different then a FAS at 20, 30, or even 40 +. Let out the clutch and she starts in the 5-speed. Illegal? In some states, you bet. I wonder how those states view AS in an Insight or HCH let alone Glide in a Prius II?

___It is up to the Insight driver to perform this and other fuel saving techniques safely just as it is up to the soccer mom to drive down the road un-distracted when taking 3 kids to soccer practice in the family mini-van. Of the two drivers I just mentioned, which of the two are more then likely paying attention to their surroundings in far greater detail?

___I am look forward to your own P&G results. I would love to see Highwater or Rick Reese nail some outrageous FE using it and I am sure those results will be passed along as are all FE saving techniques and their results to current and future Insight/hybrid owners of any type. I have to believe both Rick and Highwater are watching these results and either contemplating or performing a P&G/FAS/D-FAS strategy of their own given their hypermileage mindset. You simply cannot ignore the real world results achieved or you are not playing to the top of your game …

___Another interesting data point … The P&G technique may actually provide the CVT based Insighter’s a higher probability of receiving > FE then their 5-speed counterparts because the Pulse technique does not lend itself to lean-burn in any way, shape, or form and the low and high speed range may be just wide enough where a shift may be required for the MT owners in between reducing ones efficiency throughout the cycle. These two detriments may even the playing field a bit so that the CVT owners may actually achieve higher FE then the 5-speed owners! A real world example: On our last segment in Tom’s CVT based HCH; we hit 116.1 mpg after 10 miles. Remember how we were setup. 2 in the car, 100 #’s of stereo gear, < 50 #’s in the Bridgestone’s or Dunlop’s, spare tire, and discussing next pulse optimizations most of the time, etc. … The highest FE segment we have heard of in an HCH w/ a MT using the technique was 117.3 mpg by RJBarlow (one of the 5 “Marathon - Attempt” drivers) without the impediments I just mentioned.

___Finally, P&G or FAS’ are just 2 reasons a future EV or PHEV will/should achieve “energy” efficiencies far above the norm imho … As long as the designer lets it free coast and does not evoke Regen whenever the accelerator is let off from lower and in some cases higher speeds. The energy consumed per mile of travel appears unbeatable given the real world results any number of hybrid drivers has seen in any number of hybrid and non-hybrid automobiles in just the last 3 - 6 months. Only when the brakes are touched should that energy conversion begin take place given what a FAS or P&G have shown this old hypermiler in any number of automobiles as well …

___Good Luck

___Wayne R. Gerdes
___Hunt Club Farms Landscaping Ltd.
___[email:1ylsucun][email protected][/email:1ylsucun]
 

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It seems plausable that one could rig up a pushbutton to do the engine stop. It is my understanding that usually the ignition switch is implemented as an electrical switch opening and closing the 12v circuit, and a second circuit for the starter. The Insight probrably has an ECU controlled "startup sequence" that would be triggered by some signal from the switch, but likely opening and closing the 12volt circuit is still the mechanism by which the accessory, "on," and "off" positions are implemented. If that is the case, it seems a pushbutton, normally closed switch would work conveniently for manual autostop.
 

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Yes xcel:
reading, contemplating.......etc.
And thanks for your essays.
I am birthing the MIMA baby at the moment. hopefully Mike will be able, or someone with one of the debugr/programmer units (I have one but haven't gotten that far yet), to work out an ICE cut out of some design..........eventually.
Man.....is the future bright or what :D
Randall
 

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Highwater,

With MIMA you can do a FAS, and when you're ready to start the engine all you have to do is move the joystick to the assist position and the car will start without you touching the ignition key.
 

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I was on a long drive today (~85 miles) and I took some back roads and played a bit with trying P&G. I couldn't give it good try because I was in quite hilly terrain, but the impression I got is that it's very hard to get it right. If you accelerate hard, you use the IMA and deplete the IMA pack and then have to charge as well as accelerate and that pretty much kills it. If you accelerate moderately, you are using the least efficient range of the engine and the net MPG isn't very good. And you can't really do it in lean burn, because you are accelerating from too slow a speed to be using 5th gear.

I think the only way to do it would be with MIMA, not as a way of adding assist, but as a way of turning off the assist during the "pulse" phase!

xcel is unenthusiastic about MIMA for hypermiling because he doesn't like to use assist, but I am enthusiastic about MIMA for exactly the same reason--as a way to turn off assist.

Charlie
 
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Hi Calpod:

___A FAS built into MIMA is a very good thing indeed! Thanks for the info. Can you make sure you teach the exact details to Highwater and Rick Reese via PM in case they do not see it here?

___Chrs, the assist during a pulse is a given at a high SoC unfortunately. Honda’s screw up imho … It is at low SoC where a Forced Charge on the pulse should provide enough charge to maintain the pack at that given cap, provide enough juice to keep the 12V topped off, and provide enough energy for an IMA start before the next pulse. This is the self regulation part that I do not know if it will work as hoped with an Insight 5-speed? I have conformation that the HCH 5-speed works just like the CVT based HCH which is excellent at about 6 - 7 bars of 20. At that low a SoC, you should see a 4 bar - Forced Charge on the Pulse and that is exactly as it should be. After the SoC balance is maintained, then you only need to find the right range and rate for maximum FE. I bet it is very close to the 25 - 41 to 43 mph range we used in the HCH or maybe 31 - 37 to 40 mph range in the Prius II. That should at least get you into the ball park to begin?

___In regards to not believing in MIMA, it isn’t like that at all. I am simply looking for confirmation about its usefulness for valedictorian qual’ed hypermilers is all. There have been just 3 automobiles (2 of them Insight’s) that I know of to receive 100 + mpg tanks this year. Highwater owns one (2 of 11 tanks so far), myself (1 for 1 on her first and last tank of the year while on her final drive out to MA. in early April), and of course Dan Kroushl’s Prius II in the “Marathon – Attempt” last month. I clearly expect Highwater to take my non-Mima achieved lmpg down because of his great start and warmer year round temps but I wonder if Mima is needed to make this happen? We should know very soon if Mima is worth it or not if he can get some tanks knocked out before temps in Northern OK. begin to fall into the low 50’s by late December? If he heads out and nails a 110 mpg tank with it installed, game over dude, Mima is the kick @$$ mod of the decade :)

___Good Luck

___Wayne R. Gerdes
___Hunt Club Farms Landscaping Ltd.
___[email:2p7hth9h][email protected][/email:2p7hth9h]
 

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Speaking as one of the folks on Mike's list for MIMA, I'd like to say that my interest is in achieving very high mileage while maintaining pace with normal traffic. I drive the Insight for work, and work involves driving anywhere from 150 to 400 miles per day, over mainly 4-lane highways and on a schedule.

I have time neither to pulse, nor to glide, and I have no interest in climbing moderate grades trundling along with my emergency flashers on. Hypermileing looks like a fun game, but MIMA looks like it may be the answer to what I'm looking for: 75mpg at 70mph, with the A/C set at 70, and not getting in anyone's way. :wink: - Pat
 
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