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2009 Prius Base - Ecomodded

Discussion in 'Newbie Forum' started by Matt Herring, Apr 28, 2009.

  1. Matt Herring

    Matt Herring New Member

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    Hey Everyone...just picked up a 2009 Prius Base about a month ago and have 1 tank under my belt (511 miles/56.5 mpg). I'm an active member of ecomodder.com and have a few, simple mods done to my vehicle (partial grill block, 44/42 psi tires, Scanguage II instrumentation).

    I hypermile every second in the car using alot of Pulse and Glide as well as keeping the Prius in "dead band" as often as possible. My best commute to work over 11 miles is 73.3 mpg on SGII.

    I'm looking forward to getting some useful info. here at Prius Chat...thanks!

    Matt
     
  2. usbseawolf2000

    usbseawolf2000 HSD PhD

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    Welcome Matt. What was your previous car and how do you like the Prius compare to it?
     
  3. Matt Herring

    Matt Herring New Member

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    My previous car was a 2005 Toyota 4runner...without needing all that space, weight, etc. it's not too hard to guess how I feel about my Prius...I love it!

    After getting involved over at ecomodder.com since June of 2008 I was able to improve my 4runner mpg from 17 mpg to 21 city/25 highway mpg (pretty good considering the vehicle). I already have almost a year of hypermiling under my belt and was first tank in the Prius was 56.5 mpg so as I'm getting used to the car and slowly adding some mods I hope to approach 60, 61, 62, 63+ mpg. The warmer weather has helped too...

    Great to be on this site!
     
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  4. usbseawolf2000

    usbseawolf2000 HSD PhD

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    We share the same feeling toward our Prius as well. Don't let others mistaken it as a smug.

    20% improvement over EPA rating is impressive. Try to get a hold of Pulse & Glide (Accelerate & Coast). That technique has potential to double EPA City MPG. This is hybrid exclusive premium feature and you can easily master it in Prius because it is a FULL hybrid.

    You can do P&G with other assist hybrid and even non-hybrids but it will never approach the double mileage.
     
  5. Matt Herring

    Matt Herring New Member

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    My 11 mile commute to work (where I do about 80% of my total tank driving) is a tricky one for P&G. The course is mostly 45 mph and about 1/3 of the way I'm able to dead band it but P&G seems to give me trouble as I'm approaching the hills (probably babying the throttle too much trying to stay in dead band and then on the approach I'm not up to speed to get up the hill without revving the engine to 2100-2200 rpm). I'm still used to driving my 4runner and with its weight I was able to coast a little further and especially on the approach to hills.

    Still working on my P&G with the Prius. I had it down great with the 4runner but it's going to take some time with the new buggy. I've been relying more on dead band than P&G but maybe I need to change my approach...any thoughts of P&G vs. dead band and which produces better overall results (for 30-40 mpg driving)?
     
  6. usbseawolf2000

    usbseawolf2000 HSD PhD

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    P&G is better because you are not rolling on battery power. You will need to recharge it and pay for it with gasoline.

    During the pulse, use the ICE all you want. Don't go over 2,400 RPM or 35hp. When you finally glide, you should not have any arrow on the energy screen. Now the car is rolling as in neutral with everything seems shut off.

    It helps if you understand the four stages of Prius operations. This way, you know when the gas engine is completely off. We use the ODBII readers to see the true RPM because the MFD only show the energy flow (not RPM).
     
  7. 2009Prius

    2009Prius A Wimpy DIYer

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    Question on P&G, dead band etc. Re: 2009 Prius Base - Ecomodded

    Sorry for these stupid questions about P&G, dead band:

    At higher speed (>40mph?) I can't seem to avoid arrows going into or out of the battery?

    Can you glide by feel without looking at the monitor? I don't really feel any difference between no arrows and having arrows going into or out of the battery. I can easily adjust the gas pedal to no arrows but I need to glance at the monitor to get the feedback.
     
  8. usbseawolf2000

    usbseawolf2000 HSD PhD

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    Re: Question on P&G, dead band etc. Re: 2009 Prius Base - Ecomodded

    No, I can not feel either. Prius is too smooth :).

    The exact speed is between 41 and 42 MPH. Beyond that point, the ICE will be running below 1,000 RPM, not necessary using gasoline. It can be powered by MG1.

    Prius keeps the ICE spinning above 42 MPH is because:

    1) Gas engine is very efficient
    2) HV battery power is not sufficient or wasteful
    3) Due to #1 and #2, ICE is used more often

    To avoid the ICE restart penalty (consumes gas), it is better to maintain the ICE below 1,000 RPM by MG1.

    The above info is my interpretation of HSD so if anyone has conflicting thoughts, feel free to discuss.
     
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  9. Matt Herring

    Matt Herring New Member

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    Paying for the battery power used in dead band vs. paying for the gasoline used to power P&G...does anyone have any ABA testing to confirm which is better? My energy bars never drop below 3 and into a range where I would need the ICE to recharge the battery. With my grill block my warm up temps are 2-3 mins now.

    The proof of dead band vs. P&G is in my SGII. If you are telling me that 30-40 mph travel is more efficient in P&G than dead band I have to disagree. At 40 mph in dead band my SGII reads 4050 mph. At 40 mph with P&G and ICE engaged since I had to speed up past 40 (say 45 mph) and then back down to say 35 mph the SGII reads 130 mpg above 40 mph until it drops back into dead band during the glide. Plus, the gasoline needed to drive the pulse is more than just staying below 41 mph in dead band and using zero fuel at 4050 mpg.

    Now...for highway travel I consider P&G highly effective but at lower speeds (which I travel throughout my entire 11 mile commute below 45 mph) I see no benefit using P&G vs. staying in deadband since any contact with the accelerator past 41 mph uses more fuel than dead band.

    I've tinkered with using P&G on my commute but just don't see the results on my SGII that staying around 40 mph in dead band produces for me (about 4-5 total miles of my 11 mile commute).

    Wht kind of mpg are you getting right now and what type of commute do you have (streets, highway, etc.)? Dead band might be better for me and P&G might be better for you given we might have totally different commutes.
     
  10. usbseawolf2000

    usbseawolf2000 HSD PhD

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    P&G only works below 42 MPH when the ICE can go 0 RPM. If your commute is short, you may not reach stage 4. Use your SGII to verify the ICE is really off.

    We need to be clear on the definition of deadband. I made the previous comment thinking of using the HV battery power to maintain speed at low (<42) or high (>42) speed. Looks like this:

    [​IMG]

    The real definition of it is to power the car with ICE without any arrow to the battery. The idea is to get all the ICE power to the wheel without charging the battery. It looks like this:

    [​IMG]

    Does that match with your interpretation of the deadband?
     
  11. Matt Herring

    Matt Herring New Member

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    USB,

    Dead band, as I have seen it described, is when the ICE and EV are disengaged and no flow on the energy screen is going to the wheels from or to the battery from the ICE or battery. EV mode is when there is flow from the battery to the wheels and no ICE engaged. Regular driving mode is power from the ICE to the wheels while recharging the battery.

    I think different commutes and driving situations dictate what driving style works best in that situation. For me, P&G does not seem to produce better results than EV o dead band mode as there are many very large hills and the energy required to pulse up the hills is quickly lost on the glide into the next large hill. Consistant light throttle in EV or dead band at 4050 mph (SGII confirmed) has me at abour 60 mpg right not on my current tank. Pulsing up the hills at 15-20 mpg and then a short glide on the back side cannot equal those numbers.

    However, at highway speeds, P&G is undoubtedly the best way to maximize mpg and the Prius low CD. I agree with you on that.
     
  12. Matt Herring

    Matt Herring New Member

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    In your picture examples the one of dead band is not to the definition of dead band. Why would you want to power the wheels with ICE without also recharging the battery? And in your pic you're only at 14 mpg...that is not dead band.

    Dead band is commonly seen in neutral coast or 34-40 mph with little peddle and no energy arrows flowing on the screen. You will see 99.9 mpg on the energy screen in dead band and on a SGII you will see upwards of 3000-4000 mpg and 0 rpm to confirm you're there.

    I'm interested to hear what mpg you are currently getting with your Prius and what your daily route is in terms of terrain and distance...just curious.
     
  13. F8L

    F8L Protecting Habitat & AG Lands

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    Matt,

    I'm trying to figure out how you are getting to 41mph without pulsing and how you are maintaining a dead band without losing speed. Your posts are not clear to me and it sounds like you are using some other perpetual motion method to accelerate and maintain speed without using the ICE or the EV mode. Can you please elaborate for me?
     
  14. Matt Herring

    Matt Herring New Member

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    F8L,

    Lightly using pedal while in dead band switches the car to EV mode which allows you to accelerate up to 40 mph before the ICE kicks in. I have a SGII and my throttle position with my foot off the gas is repesented as 13 on the SGII. As long as I continue to use light pedal but don't go past 13 on my throttle position I get a little bit of acceleration and can stay at speed on flat or slight inclines.

    Basically, the car switchs back and forth from dead band and EV but the ICE never engages. But, the light throttle in EV keeps you up to speed until you get back into dead band and essentially if you were on a flat road with no traffic you could keep this up until you completely drained the battery (which would take dozens of miles).

    I am able to do this for a good part of my 11 mile commute which has produced good results for my mpg. Averaging about 60 mpg right now.

    This technique I learned about at ecomodder.com a great site for pulling great mpg beyond what factory and EPA rate the car at. I also have a grill block and max psi tires that helps me get past 60 mpg a tank. Highly recommend you check out the site if you are looking for basic hypermiling info. that all drivers can use...not just Prius drivers.
     
  15. F8L

    F8L Protecting Habitat & AG Lands

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    Matt, Thanks for the explaination. I am familair with the basics of hypermiling and P&G. When I have the urge to do so I play around with it. My best tank was 58mpg and I held 62mpg for approx. 116miles (didn't get a final picture for this)but this is over a full freeway and city commuting regime that includes traffic and 65mph sustained speed for over 120miles of the commute (152 miles total) with mostly flat land. While this isn't great by any means it did require a lot of effort and doing the P&G method on a single streath of road approx. 5miles long. The rest fo the commute is freeway and typical city driving where P&G would get me shot and super long glides are hit and miss because of traffic. :(





    What I am questioning is the use of the hybrid battery for such extended periods when you perform a dead band approach. Physics tells us that making energy from fossile fuel to power the battery for use in maintaining momentum is more wasteful than just using the ICE to provide that momentum and only using the battery for acceleration and in engine warmup situations. Energy regen is not a huge contributor to overall battery replenishment unless you are on the brakes alot or going down hills correct? So then how are you recharging the battery without using the ICE?

    I'm not argueing your technique is wrong. I just want to know more and frankly I would think that an 11mile commute on flat land would yeild better than 60mpg if one were able to P&G most of the way.

    My current comute is terrible for great mpg so I gave up on my milage for the moment and stuck my 17" wheels back on for a bit of style and safety. My milage has tanked into the low 40s. :eek:


     
  16. tom1l21

    tom1l21 Member

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    I live in MA and have a 55 minute commute every day to school with big rolling hills. I average about 58mpg but now that it has gotten hot out, I have been averaging about 66mpg. I do P&G and all the little things such as slowly approaching stoplights etc. I use 44/42 and have the goodyear integrity's with about 30% tread left. I try to keep my mpg about 1/2 my speed at all times which is my basis since I don't have a scangauge to monitor rpm's. Just my input since we live in similiar areas.
     
  17. usbseawolf2000

    usbseawolf2000 HSD PhD

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    The picture is not from my Prius. I just googled it because I figured we were not on the same page with the definition of deadband. Can you provide where you got your definition? I got mine from PC user discussion here.

    You want to because you won't have energy conversion loss to and from the battery. Deadband can display 14 MPG because you are accelerating. This can be at low or high speed, even uphill. So the MPG can swing wide.

    We call that EV mode, not that our terms are more right than yours. If we all use the same terms, there will be less confusion.

    I live near a highway. Once I get on, it is jam for the first 15-20 mins (6 miles) until the HOV lane starts. During the jam, the speed is 10-40 MPH. Overall, this section is ascending.

    Once the HOV lane starts, I go 60-70 MPH for the next 37 miles. I get off the highway and then 50 mph for 3 more miles with a couple of lights. Overall, I average about 50 MPG.

    If I avoid HOV to go slower (55 MPH in the right lane), I can average higher (60 MPG). My best trip from work to home is 65 MPG (with majority of highway miles @55 MPH).

    Video below is part during the jam from work to home:
     
  18. Matt Herring

    Matt Herring New Member

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    Nice vids...good stuff...thanks!

    My definition of dead band comes from Dan Kroushl who you can read more about in the link below (or you may already know of him)...his dead band description..."The pulse and glide technique seeks to minimize the amount of time that the engine runs, and minimizes power flowing to and from the battery. The pulse refers to deadband acceleration (no flow to or from the battery) up to 40 mph. Next comes the glide (engine is stopped, no flow at all) where the speed slowly decreases to 33 mph. The cycle continues until a stop is required. At such time the brakes are applied and some regenerative braking helps to maintain the battery level. Brakes are also applied if a downhill stretch causes the speed to exceed 40 mph.

    Toyota.com : Hybrid Synergy View : 2005 : Fall : Prius Marathoners Top 100 mpg
    By his definition he is "accelerating the car in deadband" up to 40 mph before ICE kicks in (what I had described me doing in an earlier post). On his route he prefers to continue past 40 mph in ICE before gliding. Because my entire commute is generally 30-40 mph the energy I use in deadband or EV from the battery is, I feel, more beenfically than only using P&G along the commute. The commute is not long enough to drain the battery below 4 bars and regen takes place along the route with braking as well as the brief start up cycle when I get in the car again (currently 1-2 minutes with my grill block and warmer outside temps).
    If I was driving a highway commute I could (and would) take more advantage of P&G and move away from dead band and EV mode as it would be more beneficial to P&G. I don't have that luxury on my commute and as I stated before about 350-400 miles of my tank (500-550 miles) I am on the same commute route.

    I have tried P&G several times on my commute and the numbers just don't equeal that of my current technique (I am limited to a point with my commute...If I wanted to raise my tank/lifetime mpg I'd just go "driving" for the sake of driving). I do have a lengthy trip coming up next week (700 miles round trip) and I intend to use heavy P&G...can't wait to see what mpg I can pull off!
     
  19. F8L

    F8L Protecting Habitat & AG Lands

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    Ahh ok. Deadband makes more sense now. I've toyed with that and the P&G techniques. It seems the only real difference is weather you are putting energy back into the battery or not during your acceleration phase, that's it. Or are you simply cruising along in deadband without any slowing or speeding up until you hit a stop sign?
     
  20. Matt Herring

    Matt Herring New Member

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    To give you a better picture of my 11 mile commute to work I'll try to break it down for you. (My commute to work is more downhill than the commute home).

    Mile 1: Pulling out of living community and onto 45 mph road (at this point I am in the start cycle and getting up to temp). There are two stop lights which I tend to glide in neutral coast (depending on traffic from 25-40 mph) to maximize my first 5 mins in the car. After the second light there is a long downhill coast I can utilize P&G for about 1/4 mile. By the end of mile 1 I'm up to temp.

    Miles 2 - 7: All 45 mph road...closely grouped large hills. This is where I've experimented with P&G vs. dead band/EV. Generally, I'm going along at 35-40 mph in dead band/EV except for going up hills where I will use the least amount of rmp to stay at speed without revving the engine too high rmp (and also dropping too low mph to drive the people behind me nuts). At the end of Mile 7 there is a light which I usually have to brake for (also recapturing energy at this point). During mile 2-7 I do not use the brakes at all...usually never once. I am able to use dead band accel to stay at speed during some 1/4-1/2 mile stretches before the hills take effect.

    Miles 7-9: 35 mph limit. Alot of uphill which I'm using ICE and recharging the battery at the same time. A few small flat or downhill areas I can coast below 41 mph to dead band and EV. This portion of my commute is probably my lowest mpg.

    Miles 10-11: 35 mph limit. I'm able to dead band/EV most of the last two miles. Creep along at about 20-25 mph until parking.