Pulse and Glide plus Warp Stealth in the Prius II for maximum FE …

[xcel]

Hi Tochatihu:

___I meant RAW jpg’s (in the original format with no editing). You can work with those, right

___Good Luck

___Wayne

[Tochatihu]

Yes I can. RAW image files are quite another thing.

DAS

[GaryG]

Hi All

Great article Wayne, this helps others having a hard time understanding P&G. Every car I drive, I see an increase in FE using P&G now. It’s like learning how to avoid the brakes, but you learn how to limit the gas pedal in addition.

Unless the Prius does not have a wheel end or center axle disconnect, I can’t see that deadbanding would be preferred over neutral for the glide. It may be possible to check the Prius owner’s manual for the towing requirement restrictions. If they advise it’s ok to tow in neutral, there may be an axle disconnect like the FEH.

Higher P&G speeds will never yield you better FE than under 40mph, but they are better than no P&G at say 70mph. P&G is always in the cards for me at any speed. It’s all in the management of how to limit the use of the gas pedal and coasting or gliding. So what if at speeds of 70mph you slow faster, your going to yield better FE over pushing a constant speed of energy because you demanded less during coasting time.

Every condition requires adjustments in our daily grind, P&G is part of the tools I use thanks to the people here responsible for P&G.

GaryG

[xcel]

Hi Gary:

___Thanks for noticing

___The Prius does not have a driveline disconnect like the FEH does in N from what I have been told. There are two individuals named in this article that have done the coast down tests and they end up at the same approach speed after so many tenths of a mile using either before creep takes over

___As for Deadband, this is a description of “only” power flow to the wheels via the ICE (not the MGSet and back to the pack) during a “Pulse” in Prius circles. I never really liked the term or the ability to see/achieve it so I left it out of the discussion so as to not confuse anyone. The std. “Pulse and Glide” as described is the real “killer app” approach to maximum FE in the Prius II. The FE from “P&G” works so well that I can only hope most Prius drivers will add the P&G technique to their toolbox ASAP.

___Although this article is not about the TCH, that thing is another completely different animal when it comes to P&G. It not only has a higher RPM capable MG1, MG2 is also geared via another gear set for even higher torque output at higher speeds. Another neat thing and one I have wanted to see for years is a very light Regen on accelerator let off vs. the std. wham, you are in a full blown Regen slow down from highway speeds. The TCH just barely kisses Regen until you actually start grabbing the binders. Another item I felt first hand after being told about it is the TCH is very tough to place into a pure “Glide” state w/ a lower SoC and at higher speeds. I wish I would have had more then a few minutes in one on my own route without all the weight to take it to its possible conclusion With that, I would not rule out a lengthy 100 mpg segment from one sometime in the future. I think it is capable but the TCH will have to be dropped into N for her own version of pure “Glide” to achieve a real coast free state just like the FEH. In other words, it does have a driveline disconnect in N from what I felt as I dropped her back into N within the last 30 seconds I was behind her windscreen of my short test drive. I wish I would have known about this before I had sat down in the drivers seat to get a bit more out of her even though she had < 1,000 mile on the odo …

___An additional item … Because of our 2 hours of taking pics and pushing Carl’s own Prius II for the article, I gave him some pointers on the return loop to improve upon his already spectacular tanks. With that, he is now successfully running 95 - 100 mpg segments from home to work and back vs. the 70 - 80 mpg segments previously. Keep a close eye out for this guy in the coming months because I think he has a shot at the first 95 - 100 mpg tank in a Prius II (no small feat as all of us know) while simply commuting back and forth to work with the few additional tweaks to his technique we had the opportunity to discuss.

___Finally, I would like to tweak your FEH article somewhat when it cools down in your locale later this year. What I would like to do is add some additional pics of the NAVI’s - Energy screen during the different phases of FEH LGA-N-D for EV ops as well as add a video loop with appropriate commentary to describe it even better. Maybe I can take a trip down your way w/ the digital camera and video recorder to lock it all down in late fall when it cools off. I was reading over my older Word Documents describing the Prius II specific P&G before I wrote this article and came to the conclusion I probably buried more people in detail then helped. For this article, I decided to capture on camera a very specific grouping of pics (P&G in the Real World Sequence), very exacting pic’s of the various “Pulse” rates, “Glide”, as well as “WS” as it was actually seen during the event(s). Although my pics were of poor quality, I believe it is much easier to understand the what’s, why’s, and how’s from the pics now vs. the excessive verbiage I had used in the past to describe the same technique(s) in other areas of the web. I would like to do the same for your FEH the next time we get together so as to help current and future FEH owners understand how the LGA - N - D for EV and FS is accomplished.

PS: Great thread on maintaining your FEH’s FE while using A/C to keep you and the pack at a much more comfortable temp given your location too!

___Good Luck

___Wayne

[dcoyne78]

Hi Wayne,

If you have not been sworn to secrecy by Carl, could you share some of the pointers you gave him? Undoubtedly there are others (me for instance) who are making some of the same "mistakes" as Carl was (I can occasionally pull off an 85-89 mile segment over 20 to 40 miles), the occasional highway or short errand trips kill my overall tanks.

Today I had a eureka moment (inspired by your article) while driving up a long hill. In your article you emphasized the distance of the pulse and the distance of the glide. I have often made the mistake of thinking in terms of the time spent with the ice on vs ice off. This would lead to hard acceleration at say 20 mpg so that I could spend less time with ice on and more quickly reach the ice off glide. This might make sense on flat ground and would also make sense going downhill, but going up a long hill it is unlikely that one can reach the ice off state for any length of time. If the ice will be on over the distance of the hill (call it x) why not go as slow as traffic and time will allow and get maybe 40 to 50 mpg over the distance x, rather than trying to get to some target speed like 40 mph more quickly and maybe end up with an average of 20-25 mpg over that distance x. Once you reach or get close to the crest of the hill you can use a little ev to get you to your target speed if SOC allows or once reaching the crest you can let gravity take over if the hill is steep enough, if not use a little more ice or ev to get to your target speed and then glide. You have often stated that lower rates of acceleration are your preference, and for hill climbs I am definitely seeing this, I think on the downhills and the flats acceleration at 35-40 mpg up to target speed works well. Another observation is that target speed should be adjusted down at the top of a hill because gravity will often take you up to speed relatively quickly so if your target speed is 40 only use the ice to 35 or so (depends on the steepness and length of the hill).

Dennis

[xcel]

Hi Dennis:

___What I explained to Carl is to move into and out of the 2 states a bit quicker and hold the “Glide” longer by widening the range. I noticed his accel rates were slowing as he approached the higher target speed and thus he was ICE-On for a longer period then he needed to be. I also guided him towards using EV at the bottom of the range a little longer so as to extend the “Glide” distance as well as use it to crest in a decal to regain speed on the descent. You have already discovered this last item by the latter portion of your reply. Given the way EV works, you want to transition to “Glide” before you crest, bleed off speed to the lower target and then EV over the crest for a full “Glide” accel on the descent of whatever you are climbing. The last thing was to begin the “Glide” a bit further from a known stop so as to DWB. It wasn’t much but when you put it all together; he is now besting the 100 mpg barrier on a much greater portion of his route.

___We do not have the types of hills on Carl’s Alternate Warm-up P&G route where DWL can help much within the P&G technique but in any climb, I would DWL to a mid speed target, transition to “Glide”, bleed off speed to the lower target, then EV over the crest giving away kinetic for potential smoothly. After the crest, your newly gained potential can help you back to a nominal speed with ICE-Off for the illustrious extended “Glide” we are all looking for.

___There are other tools so as to reach the illusive 100 mpg segment goal but it involves swapping back and forth between the Energy and Consumption display or having a Yoshi supplied SuperMid connected. I would prefer most simply keep the Energy display up so as to transition between “Pulse” and “Glide” smoothly and efficiently with the least amount of distraction. 100 mpg will be in their future if they can find that section of road or traffic condition that allows the technique to be exploited to its final conclusion.

___Good Luck

___Wayne

[dcoyne78]

Wayne,

I really appreciate that you take the time to answer my questions, hopefully there are others besides myself who will benefit from your tips. I mostly use the energy monitor and occasionally check consumption to see how I am doing. In order to check how my individual trips are going, I use the method you employed with Carl's Prius when you first tried pulse and glide in the prius last summer (I am a fan of yours in case you couldn't tell), so by noting the avg mpg on the consumption screen before and after a trip and recording the number of miles of the trip I can calculate an approximate avg mpg for the total trip (I only reset when I fill up). Other than this I am not sure how one would use the consumption screen except maybe to see where the 5 minute bars are (occasionally I get 2 consecutive bars at 99.9) or to see if the avg mpg is increasing or decreasing, it is not that hard to take a quick check in the middle of a glide or at a stop light, the hills tend to prevent me from maintaining the high mileage, but I am going to try some of your tips and I'll let you know how it goes. I finally checked Carl's stats over at green hybrid, I would agree with you that pretty soon he will be giving Dan K, and Lakedude a run for their money, 76 MPG may be the best tank ever, (besides Dan) in a Prius. No doubt he will surpass Dan's 86.7 tank soon and Dan will have to take the Prius back from his wife. I can't imagine what you would be able to achieve driving a prius all the time.

Dennis

[hobbit]

I'm gonna resurrect this thread as being most appropriate to present
a VERY PRELIMINARY version of my "prius sweet spot" writeup,
http://techno-fandom.org/~hobbit/cars/sweet/
I wanna bounce this one off you guys and get feedback/tomatoes
before calling it finished and spamming the Prius-lovin' world
with what I hope is the answer to all their prayers.
.
_H*

[dcoyne78]

Hi Hobbit,

Great writeup. I have been struggling with FE at speeds over 40 mph and especially on the highway, so this is exactly what I have been looking for. I usually manage around 55 mpg on the highway at average speeds of about 63 mph, I have tried using warp stealth and high speed p&g but at highway speeds I usually do just as well with cruise control and switching to high speed glides on the downhills.

I have no added instrumentation (I am thinking about a scangauge or supermid m1) so I will need to base my technique on iFCD until I add something to show me vacuum and RPM. You suggest staying between 35 and 75 mpg on the iFCD, I assume 35 would be going uphill or accelerating and 75 on slight declines or flat ground once up to speed and obviously 75 would be better than 35 all else being equal. What is not intuitive is why iFCD readings between 75 and 99 mpg would actually result in a lower overall mpg than say 60 to 75 mpg. Is this because you would not be at an optimal point on the Torque vs RPM curve (with the RPM being too low) when above 75 mpg instantaneous? I often strive for the highest possible iFCD readings without realizing I might actually be hurting my avg mpg (except when in high spped glide), it is counterintuitive, but I certainly will give it a try because I would be quite pleased with 63 at 63. One thought is that by staying higher on the torque curve and getting up to say 65 or 66 mph, you can then go into high speed glide and let the speed bleed off to say 59 or 60 mph and then pulse back up to 62 mph or so at say 40 to 50 impg (instantaneous mpg) on flat ground and then let up a little on the throttle and try to keep it at 70 impg. If you continue to accelerate up to say 66 mph then let up a little more and go into high speed glide down to maybe 58 mph or so. Is this what you have been doing? I realize you are basing your throttle position on your sweet spot meter, vacuum gauge, and rpm and not so much on iFCD, but a little more detail on how to approach this technique without extra gauges would be of interest to many. It sure looks like the scan gauge is going to be my best bet to try and nail this thing. Thanks again for sharing your findings.

Dennis

[xcel]

Hi Hobbit:

___I had planned to create a thread about this in the tech section given it could get controversial … The reason why is because we are going to be in a debate of sorts here.

____Rick Reese took his Prius I to a 70 + mpg tank using a simple Graham scanner. He found two areas where higher FE could be achieved while only concentrating on the load section and built in iFCD. IIRC, it was something like a 25% and a 70% load area (load being ??? on the Graham Scanner) where the magic appeared.

___Because you have had little to no time behind the wheel of an IMA equipped Honda hybrid and its superior instrumentation; you will find various throttle position that not only increase FE but maintains a given speed. All Honda IMA drivers actively seek out and ride this slight less throttle position while maintaining the highest FE per the iFCD possible at a given speed. Hot Georgia has spoken of this many many times in the past in fact but you can usually gain 5 – 10 mpg’s just by following the iFCD … The same should hold true in the Prius I/II. Set it up and continually adjust to get that aFCD to max for a given speed. I think you may be limiting yourself by burying the details inside your gauge package. Just a thought but if you give a Honda Hypermiler the Prius II for a week, he/she will seek out and find the same using the Consumption display’s iFCD but will be varying the TP as road conditions, traffic, and weather/temperatures vary.

___Good Luck

___Wayne