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

Discussion in 'Articles' started by xcel, Jun 22, 2006.

  1. jkp1187

    jkp1187 Well-Known Member

    I'm posting just to say that this is an excellent description of pulse and glide, and that I didn't really understand what the concept was until reading the first post. The glossary entry really should link to (or perhaps be replaced by) that post.
  2. Wilson Chan

    Wilson Chan New Member

    Hi Wayne and all HMs,

    I come from Hong Kong and drive Prius for half year. This is a wonderful thread which teaches drivers to take the most advantage of Prius' parallel hybrid system in achieving FE.

    I am still at learning stage and my reading increased from the original 45MPG (5.2L/100km) to 53MPG (4.4L/100km), certainly still a long way to go for even reaching the threshold of 60MPG! Given the nominal capacity of the fuel tank as 45L, here we each strive to make an own record of travelling 1000km with a full tank. To achieve this, one needs to be 4.5L/100km in theory for the very last drop of petrol. In practice, one has to be 4.3L/100km or lower. Not sure if there's any similar play for those in MPG.

    To help me have some breakthrough in HM, here comes the questions:

    - To start the car from stationary, the initial FE is terribly poor and FE improves gradually while the speed is increasing. So to avoid ICE on at low speed, I pressed the EV button for starting. When the speed reached 30MPH, EV would be off anyway. Bad point was the pack then probably left with only 3 or 4 bars which was not favarable for P&G and HS P&G. So now I used to start with EV button on but depress it when reaching 12-15 MPH, hoping to avoid the ICE starts from stationary, yet not to draw too much from the pack. Does this make sense in terms of FE?

    - My parking space is on 4/F. So when returning home, I press EV button and drive up as fast and safely as possible. This usually left with 3 or 2 bars when parked. The next time I drive out, ICE usually turns itself on due to low SOC or temperature. But I am on the way down and hope that regen will rise SOC quickly while ICE is warming up. Again, does this make sense? Or should I better go up 4/F with ICE on?

    - In warp stealth (HS P&G) gliding, the pack used to keep ICE spinning. In P&G gliding, if I press pedal slightly more, yellow arrow appears and it seems to help keep the speed. Is this really the case? So this time does the pack drive the ICE or keep it spinning?

  3. rickkop

    rickkop Active Member

    I understand that this forum is mostly for Prius owners but, is this pulse and glide something I can do with my 09 TCH? I have read this and am trying but am haveing a very hard time getting the screen with the power only going to the engine and the battery only? I see a lot of peopl have a scanguagII. Would this help me and if so how. Thanks, Rick
  4. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi Wilson:

    ___A good rule of thumb is to bring the Prius-II and –III up to 15-mph under EV and than bringing the ICE online. You can go higher but the SoC payback is harsh as you well know. I use 15 mph under most circumstances and it has proven its worth time and time again.

    ___End of the day SoC is a hard one. Here in the US, the ICE will start and not supply any power unless a high percentage of throttle is demanded. The Prius-II will accelerate on the pack and MG2 even while the engine is idling at 1,200 + RPM during to warm-up to achieve S1. It is absolutely ridiculous that it works that way but that is the way the Prius-II was designed for us here in the US to meet the strict emissions standards more than likely.

    ___During WS, the pack does indeed keep the ICE spinning over. It is a limitation of HSD to protect or limit current on MG1 when trying to start the engine while it is above 6,500 RPM at 41 mph. We have a technique we call Warp-Neutral wherein we engage N before we reach 41 mph and let it increase up to 62 mph (MG1 spinning at 10,000 RPM backwards) without the pack spinning up the ICE. This can only be used on downhill’s as you will not accelerate above 41 mph without the assistance of gravity.

    ___There are some limitations that can be exceeded with the above but that is best left to direct discussions with those in Japan that actually designed MG1 including its actual capabilities ;)

    ___Rickkop, CleanMPG is about all vehicles including all-electrics to 18-wheeerls. This thread is about HSD and your TCH can use similar techniques. To glide however, you will have to run N as the dead band is simply to small to control with your accelerator. If I ever get the opportunity to review a TCH (I really should get on this but Toyota has always been out when I have requested one), I will write-up a TCH specific technique section. You will be looking for 18 TPS and 18 IGN via a ScanGauge-II for 60 + mpg highway driving and using P&G around town with N to hold your glides is what it comes down to.

    ___Good Luck

  5. rickkop

    rickkop Active Member

    I'm sure there a lot of us TCH owners out there that wish Toyota would get a TCH for you to review. Looks like if I'm going to be serious about mileage I better get myself a scanguage. Thanks for the help, Rick
  6. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi Rick:

    ___No problem and like I say to many TCH owners in person, you have one heck of a nice automobile and most importantly, enjoy it :)

    ___Good Luck

  7. tom1l21

    tom1l21 New Member

    This is only if you have excess SOC, e.g. 68 or 70 correct? And is this the optimal way to use the excess SOC?

    I absolutely hate this. Even when the engine temp is say 190F from a previous trip, the engine will still behave this way, albeit for a much shorter time than the usual minute. Is it best to gun it up to 2200 RPM to bypass the excessive use of the battery or should you ride it out at very low RPM and very light acceleration so it won't take too much off the battery. I can sometimes lose 5 off my SOC in this phase if I accelerate normally. What is the best way to handle this?

    Another couple questions I have is: should the pulses for P&G for rural 35mph driving be IGN 14? And using P&G + EV button from startup to get to S4 is not damaging to the ICE or any other components is it?
  8. brucepick

    brucepick Well-Known Member

    What are MG1 and MG2 as mentioned in the Warp Stealth section of the article? They don't come up when searched for a definition.
  9. JimboK

    JimboK One owner, low mileage

    They are the two motor/generator units. Here is a user-friendly description of their design and operation (along with other aspects of Prius propulsion system function). Though the site describes the 2001-2003 model and some minor design changes were made in 2004, the MG concept and functionality are the same.
  10. Pat8635

    Pat8635 New Member

    I have many miles in a 2006 Prius that was my parents. Because of the Clean Fuel plates and HOV usage, I left it in Northern VA with my sister whose husband has a bad commute and the HOV usage is key for him. I looked around and decided to get the Lexus HS250h. I am getting over 40mpg most of the time, but am finding that some types of fuel are much better for FE than others. Shockingly Chevron is about the worst so far. Probably another thread.

    I had discovered the Glide on the Prius and used it all the time. Used to make my mom nuts as I would glide down to the turn for her house and w/o braking be able to make the turn. It was an over 55 community, so no-one gave a second look to a slow moving car.

    In the HS250h I can't seem to find the sweet spot in the accelerator to glide.... I can feel what I assume from what I know about the Prius, the MG1 cranking down but find that it is very hard to release. It has a display that shows if you are charging or using batter (like a tach) and even using that have yet to find the glide.

    Anyone have any ideas on why this is...it is the same system right?
    Last edited: Oct 4, 2010
  11. BeachPri

    BeachPri New Member


    I'm a new member to the forum, hypermiling and Prius III ownership. What a great resource this site and some others have been. Looking forward to contributing as I learn & experiment.

    Have been trying various techniques. With 4k on my 2010. For the last 1k am averaging 62.6 mpg. Have all tires at 44, what is the reason for suggested difference between front and back pressure?
  12. ItsNotAboutTheMoney

    ItsNotAboutTheMoney Super Moderator Staff Member

    Front heavy cars need extra pressure on the front tire.
  13. deleond2

    deleond2 Well-Known Member

    I dont know if it was luck or not, but after reading this article last night I left for the gym. The battery's charge was pretty low and the engine was cool. I drove the Fusion 1.9miles to the gym at about 40mph. I was not able to get it into EV mode but it charged up the battery pretty good. The trip to the gym was about 31mpg. After spending 2 hrs at the gym I left for home, the engine had cooled down alot but the battery was charged up pretty good. I got the Fusion up to 40mph and then started my glide, It took me a few seconds to adjust the accelerator into the happy spot where there is no regen or use of the battery. Of the 1.9 miles home, I able to go the final 1.2 miles using no gas. I got 74mpg on the trip home. Maybe it was a fluke or good luck, but the 74mpg (my previous best on the home from the gym was 63mpg) has motivated me to continue trying the P&G method. The article was very informative and was very easy to understand. Xcel, can you direct me to other articles such as this? Plenty of info but easy for a hybrid beginner to understand? The "Beating the EPA" link on the home page is good starting point, but now I wanting more!
  14. diamondlarry

    diamondlarry Super MPG Man/god :D

    It definitely wasn't luck; there's a lot more available with some practice if the Fusion is anything at all like the Prius. I drove to our county fair today with all 4 of us in the Prius and all I really did was P&G from 40-30 mph and glide up to corners with stops and I was able to get just over 83 mpg on the 15 mile or so trip on mostly country roads. I probably could have squeezed 90+ out if I had tried real hard but I was happy with what I got since the last mile or less was stop and go getting into the fairgrounds.
  15. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi Delond2:

    You are hooked and I am damn proud of you for it :)

    And driving an FFH no less makes it all the more sweet!

  16. deleond2

    deleond2 Well-Known Member

    Thanks guys. I tried it again on my trip to the gym today. I got 65mpg on the way home from the gym. It could have been higher but I had to stop at a traffic light. The previous best of 63mpg mentioned above was without stopping at any lights. I will see what I can do on my drive to/from work tomorrow.
  17. FSUspectra

    FSUspectra Practicing true conservatism!

    Awesome! This makes me happy, echoing Wayne. :)
  18. uRabbit

    uRabbit Well-Known Member

    I'd love to see a write-up on this technique in a gasoline-engine vehicle, such as mine. I currently do not use P&G for two reasons: 1) crazy drivers, 2) lack of knowledge about how to perform the technique successfully in a combustion engine.
  19. FXSTi

    FXSTi Well-Known Member


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