pulse and glide

Discussion in 'Gen 2 Prius Technical Discussion' started by tf4624, Dec 7, 2009.

  1. tf4624

    tf4624 Active Member

    Joined:
    Dec 4, 2009
    517
    49
    0
    Location:
    USA
    Vehicle:
    2008 Prius
    Model:
    N/A
    Ok i love pulse and glide but


    from what i read you can't do more then 41 cause of the gas engine.. but even if i do 50 down to 40 i can still coast/glide.. so do u mean to minimize the engine ever turning?

    i live up where im mostly up hills.. so does this mean i cant really do this compared to just driving the prius as is?

    i tried this on the hwy.. i have mostly flat.. so it doesn't work?

    I have read.. there must be something i missing ... or is it that i don't know these definitions?
     
  2. ksstathead

    ksstathead Active Member

    Joined:
    May 1, 2007
    1,244
    242
    0
    Location:
    Kansas
    Vehicle:
    2010 Prius
    Model:
    III
    A little unclear on your questions, but let me take a shot:

    pulse & glide is limited to a top speed of 41 (gen II) and 45-ish (gen III). During these glides (not coasts), the ICE is not turning or using fuel. These speed caps are necessary to protect the MGs from excessive rpm within the HSD. For a nice graph of the gen II limits, search for nomograph. In a glide, there are no arrows on the screen. It requires a little bit of throttle to avoid the regen found in coasting. You avoid regen in order to extend the glide distance that you purchased with the previous pulse, because regen is not 100% efficient.

    warp stealth is similar to pulse & glide, but operates at speeds above the P&G cutoff. Here, the ICE is turning to protect the MGs (but not burning fuel) in the glides. With a scanguage, you can see that fuel is cut (impg=9999), although there is a small assist from the pack that is not present below 41.

    warp neutral is when you shift to neutral below 41 mph, and let gravity increase your speed up to 60. Don't exceed 60 for the good of the MGs.

    These techniques and others can be applied to optimize your mpg in your specific traffic and terrain.

    If you search for these terms, you should find extensive threads to study. The jist of it is to let off the gas after a pulse, then ease back in until regen is negated. It should feel just like being in neutral in a normal car. In other words, there should be none of the drag you get in a normal car from the transmission when coasting.
     
    2 people like this.
  3. richard schumacher

    richard schumacher shortbus driver

    Joined:
    Mar 27, 2004
    7,656
    992
    0
    Location:
    United States
    Vehicle:
    2004 Prius
    Model:
    N/A
    The easy way:
    Gliding (no arrows on the "Energy" display; learn to do this by applying just the right amount of gas pedal) is better than coasting
    Coasting (arrows into the battery on the "Energy" display) is better than braking
    Light steady braking is better than sudden hard braking
    Any braking is better than stopping
    Stopping is better than running into something.
     
  4. tf4624

    tf4624 Active Member

    Joined:
    Dec 4, 2009
    517
    49
    0
    Location:
    USA
    Vehicle:
    2008 Prius
    Model:
    N/A
    so correct me if im wrong but GLIDE is not coast with Neutral?.. cause you get the same effect of no ARROWs and no engine on and u just glide along?

    what is this thing with the "engine not on but "spinning""

    what is the "MG"

    why not coast/wrap in neutral past 60..doesn't make sense since im in neutral-cant do anything wrong?

    See below.. whats the difference in negating it to black sceen verses just doing neutral?


    If you search for these terms, you should find extensive threads to study. The jist of it is to let off the gas after a pulse, then ease back in until regen is negated. It should feel just like being in neutral in a normal car. In other words, there should be none of the drag you get in a normal car from the transmission when coasting.[/QUOTE]



     
  5. fuzzy1

    fuzzy1 Senior Member

    Joined:
    Feb 26, 2009
    13,833
    7,398
    90
    Location:
    Western Washington
    Vehicle:
    2012 Prius
    Model:
    Three
    To respond to just a couple items ---
    MG1 and MG2 are the electric Motor/Generators are the core of Toyota's (and Ford's) hybrid system.

    Neutral does not mechanically disconnect anything. It only removes electric power from the two Motor/Generators, so they cannot do anything except freewheel. Because of how the system is built, this also disables all power flow from the gasoline engine to the wheels. This is the same effect as lifting one drive wheel of an open-differential car. The lifted wheel spins freely, so no torque reaches the wheel on the ground.

    Because of how all the pieces are connected, whenever the wheels turn, MG2 also turns. MG1 and/or the ICE (gasoline engine) must also turn, even if they are freewheeling without providing power. When the ICE is not spinning, MG1 is in danger of spinning beyond its mechanical limits if you roll too fast.
     
    1 person likes this.
  6. ken1784

    ken1784 SuperMID designer

    Joined:
    Dec 18, 2003
    2,940
    1,340
    67
    Location:
    Yokohama, JAPAN
    Vehicle:
    2010 Prius
    Model:
    N/A
    Please understand Prius is different animal between below and above 42mph.
    Below 42mph, the no arrows gliding and "N" gliding are similar.
    The MG stands for Motor/Generator.
    Above 42mph, the engine has to spin to protect its mechanism.
    On highway gliding, the engine runs in a fuel cut mode, but it is driven by MG1 consuming few kW of energy. Sometimes, it's called "warp stealth".
    When you shift to "N" above 42mph, the engine does idling consuming fuel. It's worse than fuel cut mode.

    [email protected]
     
    1 person likes this.
  7. tf4624

    tf4624 Active Member

    Joined:
    Dec 4, 2009
    517
    49
    0
    Location:
    USA
    Vehicle:
    2008 Prius
    Model:
    N/A
    so its ok to do neutral under 41..

    and what is this wrap stealth if i let off a little on pedel so it blacks out the screen with no arrows

     
  8. uart

    uart Senior Member

    Joined:
    Sep 7, 2009
    4,215
    1,180
    0
    Location:
    Australia
    Vehicle:
    2005 Prius
    Yeah one of the motor/generators (MG1) tends to spin pretty fast if the engine (ICE) is stopped. At 41 mph this generator spins at approx 6500 RPM with the engine stopped. The computer management system limits it to this maximum in glide mode by forcing the engine to spin if you try to glide over 41 mph. If you "glide" over 41 mph then it's just not quite as efficient because the engine is turning (without using gas).

    If you engage neutral then the engine is stopped and there is really nothing to stop MG1 spinning faster than 6500RPM. Apparently though it's rated up to 10,000 RPM so you should be ok to coast in N up to about 63 MPH with any real risk.

    BTW. You should take a look at eaharts site (link below), it has a really good animation of exactly how this works. Remember that the MG2 is directly connected to the final drive and so is always directly proportional to the actual vehicle speed.

    See : Toyota Prius - Power Split Device
     
  9. tf4624

    tf4624 Active Member

    Joined:
    Dec 4, 2009
    517
    49
    0
    Location:
    USA
    Vehicle:
    2008 Prius
    Model:
    N/A
    ok so rule of thumb do the Glide pulse to 30-40mph
    when i go over then how do i apply the Stealth techniqe ..cause your not suppose to do neutral above this speed?...


     
  10. F8L

    F8L Protecting Habitat & AG Lands

    Joined:
    Aug 14, 2006
    19,011
    4,063
    50
    Location:
    Grass Valley, CA.
    Vehicle:
    Other Non-Hybrid
    Model:
    N/A
  11. qbee42

    qbee42 My other car is a boat

    Joined:
    Mar 2, 2006
    18,058
    3,037
    7
    Location:
    Northern Michigan
    Vehicle:
    2006 Prius
    You use basically the same technique: accelerate up to speed, feather the pedal to eliminate regeneration, coast down, repeat.

    From a philosophical standpoint it's all the same. Down in the details the difference is that ICE is always spinning at higher speeds, so the gains will be limited. It still works, but not as well as low speed P&G. Likewise, at higher speeds you pay a price for aerodynamic drag.

    Try to avoid P&G over the transition speed, as this will cause the ICE to start and stop.

    Tom
     
  12. ksstathead

    ksstathead Active Member

    Joined:
    May 1, 2007
    1,244
    242
    0
    Location:
    Kansas
    Vehicle:
    2010 Prius
    Model:
    III
    Basically, don't use neutral until you have mastered P&G, Warp (not wrap) Stealth, and Super Highway Mode. Those are your bread and butter techniques. Warp neutral is just a little extra for experts, by comparison. You need to understand that those three primary techniques do not involve any shifting (to neutral or otherwise) in their basic form. Instead, the gas pedal and extra instrumentation (e.g., scanguage or canview) are used to achieve these techniques.

    If you have arrows, you are not in a glide, but rather you are either supplying power or regeneration, thus defeating the goal of pulsing and gliding. Above 41 there will be arrows indicating assist from the pack, but the assist is quite small.
     
  13. ken1784

    ken1784 SuperMID designer

    Joined:
    Dec 18, 2003
    2,940
    1,340
    67
    Location:
    Yokohama, JAPAN
    Vehicle:
    2010 Prius
    Model:
    N/A
    I've tried Warp Stealth and SHM, but the mpg gain is very limited.

    A rule of thumb on highway = slower is better

    Usually a highway driving is a long trip. My recommendation is driving with cruise control and be just relax, comparing to strain your nerves for these techniques.

    [email protected]
     
    2 people like this.
Loading...