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How to drive in the hills

Discussion in 'Gen 2 Prius Fuel Economy' started by KV55, Apr 17, 2007.

  1. KV55

    KV55 Member

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    Much of my driving is a landscape of rolling hills, typically going up and down 120 feet every mile or so, with very few stretches of flat in between. Pulse and glide is great for those 40mph drives along smooth flat roads but perhaps not the ideal way to get the best mpg when going up and down like a yo-yo.
    I have been trying to go up hill with battery assist, whilst using the downhill stretches to recharge the battery. I find getting the into the battery assist state is not so easy and it means a healthy push on the accelerator, letting up towards the crest.
    It makes sense to go up the steeper and shorter hills, and down the more gentle longer ones, so I try to pick a route that maximises this.
    Anyone have any thoughts?
     
  2. efusco

    efusco Moderator Emeritus
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    <div class='quotetop'>QUOTE(KV55 @ Apr 17 2007, 07:13 AM) [snapback]424534[/snapback]</div>
    You didn't mention traffic conditions or speeds or whether you have CAN-View or Scan Guage so that limits my advice giving ability. But living here in the Ozarks there's not much besides rolling hills.

    What I do is almost the opposite of what you do (but again, without a good idea of how steep the hills are or your speeds you may be doing the best for the circumstances). The main commute roads I take are 35-45mph speed limit 2 lane roads usually with little or no other cars to be concerned about and I use CAN-View. I try to maintain ~1850rpm (1700-2300 range) on the uphill segments until I hit about 39mph. As I approach the crest of the hill I feather the pedal into a glide. I then sustain that glide as long as possible down the hill and up the next...if it's a small rise sometimes I can maintain glide only over that hill and pick up speed again down the back-side. If it's steep I'll usually start my 1850rpm acceleration when my speed hits ~35mph (maybe 30mph if it's truely a no-traffic situation).

    If you're talking about steeper higher hills at highway speed you can forget all that, for the most part. Just accelerate up the hill to maintain whatever speed you're comfortable with...if you can keep the RPM at 2300 that's ideal, 3000 if you must, but do whatever you need to get over the hill. On the downhill side it's still better to glide and maintain momentum than it is to regen...remember that regen is wasteful compared to maintaining momentum....it's more efficient than slowing without regen.

    Hope that helps...or at least makes some sense.
     
  3. Skwyre7

    Skwyre7 What's the catch?

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    I drove this type of route for the first year that I had the car. I just set the cruise control and let it go. Now I know better. :lol: When I drive over hill terrain, I usually keep a steady foot on the accelerator, keeping my RPMs around 1800-2200. Sometimes the battery assists, sometimes it doesn't. I usually end up slowing near the top of the hill, use the momentum to carry me over the top and back down. I'll try to get a good warp-stealth glide going all the way down and starting up the next hill. I'll hit the gas again, and so on. I'm nowhere near a constant speed. In fact it can fluctuate by 10-15 mph. Luckily, my wife likes to sleep in moving cars, so she doesn't get too upset. Hope this helps.
     
  4. hobbit

    hobbit Senior Member

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    Gently rolling countryside, to sort of sum up, almost *forces* you to
    do exactly the right thing with the Prius. It's the dead-flats that
    are sometimes the problem in certain speed ranges!
    .
    _H*
     
  5. bestmapman

    bestmapman 04, 07 ,08, 09, 10, 16, 21 Prime

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    <div class='quotetop'>QUOTE(KV55 @ Apr 17 2007, 08:13 AM) [snapback]424534[/snapback]</div>
    I am kind of new at this, but here is what I have been doing.

    The hills in my area are steep enough to allow "coasting" downhill and not lose speed or I can even gain speed, Also I don't like to drive slow so I keep my speed up to 65 or higher all the time. I have tried using the warp stealth mode on the downhills. The problem with warp stealth is that the battery discharges and although this works good going down the hill, when I get down to the bottom of the hill, the battery has dischared quite a bit. On the next uphill the the battery usually charges and and this makes the engine work harder thus lower fuel economy. this tecnique usually yeilds me 45 mpg or so on the hilly area.

    I have done some experimenting and I have found that in the "B" mode you can get into a mode that on the screen allows you to turn off all the power indicators like glide below 42 mpg.

    How I achieve this:

    On a downhill above 42 MPH retract the Go-Pedal all the way and reapply to enter Warp-Stealth. Once Warp-Stealth is achielved switch to B. Adjust the Go-Pedal (usually slightly more pressure) and all the energy flow indications will go out. Just as in low speed glide (below 42 MPH). The only time this will not work is if the battery is low. It seens to want to charge it one way or another then. I do not retract the Go-Pedal in the B mode as it goes into the high regen mode and slows the vehicle to much.

    The end result is that at the end of the long downhill the SOC(State of Charge) is higher than if I went to warp stealth. It takes some practice but is easy to achieve once you learn how. This technique seems to improve my fuel economy 2-3 mpg in steep hills.

    Some of the guys with the CAN-VIEW said that there is actually some fuel flow with this technique and there is none with warp stealth. I think that the small amount of fuel flow in the "B-glide" mode is more than made up for by not discharging the battery as much.

    The other possibility is that there is no difference or that gliding in B doesn't make a difference and I am doing something different to get the better fuel ecomony. Like I said I am still new at this.

    You may want to try it. If you do, let me know what happens.
     
  6. KV55

    KV55 Member

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    <div class='quotetop'>QUOTE(efusco @ Apr 17 2007, 01:28 PM) [snapback]424541[/snapback]</div>
    I have a scan gauge in the post so the rpm monitoring will be an option soon. The roads have other light traffic and I try to keep around 50mph or so but will go slow when there is no one around to see me :p

    Some downhill sections can give me too much speed and so the battery gets a boost, so I try to put this to use on the uphill section. On Monday I noticed that by starting off at the top of a hill from stationary and in EV and then by backing off to the no arrows state before going through the 31mph EV limit, the no arrows state remained through to 50mph. I think this was too long a duration to be MFD lag. This might fit in with what bestmapman has, although I stayed in D rather than B mode. I will give the B mode a try to see how it compares with a very light touch warp-stealth.
     
  7. hill

    hill High Fiber Member

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    I basically go as slow as possible up the hill, than as many others do, glide over the top, then do a glide / nonrecharge down hill. That builds up way more speed for the next hill, where I do it all over again. Mileage seems to neither loose or gain using this technique.
     
  8. subarutoo

    subarutoo New Member

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    Just drive the car. I think some of you guys are overthinking the process. Put it in drive, step on the gas pedal, and the car will figure out the rest. Don't forget to steer when the road turns. Sheesh.
     
  9. efusco

    efusco Moderator Emeritus
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    <div class='quotetop'>QUOTE(subarutoo @ Apr 17 2007, 02:47 PM) [snapback]424820[/snapback]</div>
    Thanks for the very kind advice...but no thanks.
    "Just Drive It" is just fine, I don't condemn it and, in fact, encourage it to most people. But that's like telling someone with a 'vette to just drive the speed limit and obey the traffic laws IMO. What's the point of a performance vehicle anyway other than to enjoy and explore it's ability to perform.

    The Prius IS a performance vehicle...it's just that it's performance is about high fuel economy and low emissions...some of us enjoy exploring the limits of those performance features. I don't know why that should bother you in any way, nobody's forcing you to do it, but why criticize those of us who do....Sheesh.
     
  10. chogan

    chogan New Member

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    <div class='quotetop'>QUOTE(hobbit @ Apr 17 2007, 10:39 AM) [snapback]424601[/snapback]</div>
    Yeah -- it IS pulse-and-glide, just minus the annoying change in speed you get using pulse-and-glide on the flat.
     
  11. cc9150

    cc9150 New Member

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    1mph? 3mph?

    Are you getting in the way of traffic while you do this?
     
  12. hobbit

    hobbit Senior Member

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    Um, "B" mode gains you nothing in the context you described it.
    Re-read the description, you'll see why.
    .
    _H*
     
  13. KD6HDX

    KD6HDX New Member

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    <div class='quotetop'>QUOTE(efusco @ Apr 17 2007, 12:52 PM) [snapback]424825[/snapback]</div>
    I agree with Subarutoo: Let me criticize myself. I have noticed myself loosing focus on the road when I try and pay too much attention to the MFD. Since I commute in So Cal on the freeways no less, I am not able to pay that much attention to all of the cool video on the MFD. More than once while on city streets, I have caught myself drifting into another lane just because I was trying to save a thimble full of gas on the way home. Sheesh Doctor Foosball, take a chill pill. :lol:

    Maybe I'll be kicked off the site now? Who knows, but I would hate to be behind me on the road when I'm driving the freeways of So Cal and distracting myself with the MFD. Just a joke Doc, if I may.

    Dave
    Averaging 45-50 MPG - depending on Southern California real world driving conditions without the ultra warp, stealth and glide cyber-squat ganglia viewer. :blink:
     
  14. hill

    hill High Fiber Member

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    <div class='quotetop'>QUOTE(cc9150 @ Apr 17 2007, 05:48 PM) [snapback]424911[/snapback]</div>
    Oh, sorry . . . didn't realize anyone would over think it. No ... not 1mph, or 3mph. Forgive me for not stating what I thought was obvious . . . that "slow as possible" meant "prudently possible". Guess I better define that concept now too. ~ SLOW WITHOUT PISSING OTHERS OFF :rolleyes:

    For example ~ the speed limit (that's supposed to be the fastest we go, right? ) is around 40mph? Then if traffic is 2 lanes each side of the road ... in the right lane ... maybe 35mph? If no traffic, maybe 30? If I can find another slow car, I get behind them, validating my SLIGHTLY slower speed. Sheesh, it's a theme that yields better mileage, not a rigid formula. You really couldn't guess that?

    KD6HDX, David (Who is averaging 45-50 MPG - depending on Southern California real world driving conditions without the ultra warp, stealth and glide cyber-squat ganglia viewer):

    I'm averaging 57.8-61.7 MPG - depending on Southern California real world driving conditions WITH the ultra warp, stealth and glide cyber-squat ganglia viewer.
     
  15. JimboK

    JimboK One owner, low mileage

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    <div class='quotetop'>QUOTE(KD6HDX @ Apr 17 2007, 08:05 PM) [snapback]424968[/snapback]</div>
    Since you're mocking somewhat those of us who use hypermiling techniques and the "ganglia viewer" (which I assume is the MFD -- correct me if I'm wrong), I figured I'd jump in.

    Checking the MFD briefly and periodically, in combination with watching the road and modifying my driving, has saved me significant amounts of fuel. I wasn't thinking about becoming a safer driver when I began hypermiling, but I have become one. I am much more aware of the traffic around me, I no longer engage in aggressive driving, I don't tailgate anymore, I don't do jackrabbit starts, I slow down well ahead of expected stops, and I'm less distracted by the radio, cell phone, my passengers, other drivers, and the landscape beyond the asphalt. I've drifted into other lanes for many of these reasons, but not for checking the MFD.

    I too would be concerned if someone paid more attention to the MFD than the road. If that's your case, then you've made the right decision for you. I respect your decision. How about respecting ours?
     
  16. KD6HDX

    KD6HDX New Member

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    Listen Jimboy,

    I drive our prius almost 3,000 miles a month, most of which is in the carpool lane. In the wee hours of the morning, I can slow down to about 55-60 MPH. On the way home, I have to drive with the flow of traffic in the carpool lane (about 70 MPH on cruise control). Driving 55 in the carpool lane would be following the law to a tee, but it would be imposing my driving habits on those I share the road with. It is impossible to drive for fuel economy in the carpool lanes during peak travel times here in Kellyfornia. When the car was new, sometimes I drove 55 in the carpool lane, but that turned into a grill in the rearview from trucks busses and other vehicles flashing high beams.

    I wish I could drive on city streets to and from work, but I can't. I carpool with my wife three days a week, she drives it solo the other two, and I use it by myself on a weekend shift. I have said many times before, I did not buy this car to save the whales. We bought a Prius to save a buck at the pump, and more importantly or selfishly, to be able to drive solo in the carpool lane. It would be nice to master the techniques of hypermiling and all that stuff. But I just drive it and do more than the next commuter to try and do the right thing. No EV mods, no can view, no nothing. Just cruise control most of the time behind the wheel for us. The car is stock. It has 54 thousand miles on it now and it's still running good. Although it is not getting as good a mileage figure as you and the Foosball :lol: (sorry, could'nt resist) get, I am doing my part to save the whales or whatever.

    No jackrabbit starts for me, no tailgating here either.
    I would'nt know a can-view from a can of beer. Not important to me yet. Glad there are can views for those that want them.

    D
     
  17. Zendriver

    Zendriver Junior Member

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    People spend too much time in this world concerning themselves with OTHER people's behavior. I'm no less guilty of it than others...but here's my soapbox speech:

    If you are a gear-head who enjoys buying $1500 of gadgets to save a couple bucks in gas, go for it! And enjoy it! (I'm well below $1500 but my burn rate should get me there in a couple months! :p And yes, I have fun doing it! )

    If you're a MFD-watching nerd who gets excited about increasing each tank's mileage by 0.1 mpg? Cool! See if how high you can get!

    If you bought a Prius as a "living" bumper sticker saying "I care about the environment" good for you! Enjoy being clean and green!

    If you bought a Prius since it's bigger on the inside than the outside, great! Enjoy the secret space you've discovered.

    If you bought the Prius to thumb your nose at big oil companies? You can thumb that nose whether your getting 40 or 60 mpg!

    If you're a Democrat who bought one to prove Bush's green house policy is as misguided as everything else he's done? Go ahead! Stick it to "the man".

    If you're a Republican who's out to prove that conservatives can be gas-conservationists? Good for you! You've proven your point.

    If you bought a Prius because it's cool and all the Hollywood stars drive one? Hmmm...maybe you should have thought twice about your motivation :D

    As Garrison Keillor says in the Toyota Ad on Prairie Home Companion: "There are many reasons to drive a Prius, find yours at toyota.com"


    There...I feel better now. :)
     
  18. efusco

    efusco Moderator Emeritus
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    Foosball?
    Perhaps you missed the key first statement in my post back there before you decided to start making fun of my name out of the blue and making assumptions about my driving. Let's review shall we....
    Apparently your driving conditions and style put you into that "most people" group.
    I, OTHO, have the opportunity to drive rural country roads the majority of the time and at non-traffic hours the rest of the time. When I find traffic and conditions demand more attention I give it my attention. When traffic and conditions allow I enjoy pushing my hypermiling limits.
    Why is it that every dipwad that wants to argue against hypermileing assumes that we're all going 20mph blocking traffic on the freeway with our eyes glued to the MFD?

    I won't speak for the rest of the world out there, but when there is traffic behind me I maintain the speed limit or faster. I drive safely...I've got 3 kids and a wife that would rather I not kill myself or anyone else for that matter.

    When I drive on the freeway I set the CC to the speed limit (and if you won't tell the state troopers sometimes even go over the limit on the freeway--Shock!).

    So, let's save the 3rd grade name calling, stick to factual arguments and politely offered opinions and maybe we can all continue to get along and there'll be no need to kick anyone off...I think we can all agree that this is probably not a topic heated enough to get so worked up as to warrant such action.
     
  19. JimboK

    JimboK One owner, low mileage

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    <div class='quotetop'>QUOTE(KD6HDX @ Apr 17 2007, 09:15 PM) [snapback]425000[/snapback]</div>
    To that extent, we're in the same boat.

    I'm not sure why you feel compelled to explain your decision of how you drive. Again, I respect it. I wasn't challenging you or even questioning you. I'm just asking for the respect to be mutual.

    On that subject, the name is not Jimboy.

    And we've strayed off topic. Out of respect to the OP and the others discussing his question, we should continue this, if you wish, in a new thread or PM.
     
  20. Zendriver

    Zendriver Junior Member

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    Good point...back on topic :blink: :

    I've tried to compare various techniques but haven't driven the same hills enough to telling the difference (no major hills on my regular route).

    Cruise Control - Seems too active on the go pedal for my taste...but can approximate a pulse and glide depending on steepness.

    Steady gas pedal - Probably not the best given Prius characteristics.

    Anticipate hills, keep rpm in sweet spot, glide when possible - I would guess under controlled conditions this would be the best. But you have to adjust based on traffic pressures. I don't get too hung up on efficiency on two-lane roads with people behind me...

    PS - One complaint about Prius Cruise Control... since it's drive-by-wire, I can't "feel" where the cruise is moving the pedal, so it's more difficult to override it when nearing an uphill. Anyone found a workaround? Engine rpm can be a clue, but I miss the foot-feel.