+ Reply to Thread
Results 1 to 6 of 6
  1. #1
    Junior Member
    Join Date
    Apr 2007
    Posts
    0

    Hybrid driving technique "N", "L" and "FS"

    Calling GaryG.
    Wow! There is a lot of specialized hybrid driving techniques one can utilized or just learn about. I'm still curious about shifting into "N" and the effects on the internal combustion engine (ICE). What does shfiting into N do for fuel efficiency? I am not interested in the advanced forced auto stop (FAS) technique at this time.

    If I am correct, if you are in electric mode at the top of a steep hill and you shift into "N", you will still be in electric mode at the bottom of the hill even when you gliding speed exceeds 40 mph. If you are in ICE at the top of the hill and shift into "N" you remain in ICE when descending the hill.

    If I read correctly, users will shift into "N" during the "glide portion" of pulse and gliding technique. What happends here to the ICE?

    You recent description of your performance in the hybrid mileage event included something like "I must of fake shifted (FS) 100 times during the event" made me take a closer look at this technique. I knew lifting your foot off the pedal would cause a decrease in RPM'S and thus an increase in fuel efficiency. Am I correct to add, FS also provides a small "boost-charge" to the HV battery in "D" as well as "L"?

    One can shift into "L" prior to braking to slow the vehicle down and to provide an additional boost to the HV battery. One also shifts into "L" after the ICE restarts or shortly before the ICE restarts when the hybrid battery display indicates it is reaching its allowable discharge limits. Naturally if one does not have the hybrid/navigational headunit in their vehicle, it is difficult to determine when this should occur.

    Your thougts?

  2. Remove Advertisements
    HybridCars.com
    Advertisements
     

  3. #2
    Junior Member
    Join Date
    Oct 2006
    Posts
    0
    Quote Originally Posted by billyk24 View Post
    Wow! There is a lot of specialized hybrid driving techniques one can utilized or just learn about. I'm still curious about shifting into "N" and the effects on the internal combustion engine (ICE). What does shfiting into N do for fuel efficiency? I am not interested in the advanced forced auto stop (FAS) technique at this time.

    If I am correct, if you are in electric mode at the top of a steep hill and you shift into "N", you will still be in electric mode at the bottom of the hill even when you gliding speed exceeds 40 mph. If you are in ICE at the top of the hill and shift into "N" you remain in ICE when descending the hill.

    If I read correctly, users will shift into "N" during the "glide portion" of pulse and gliding technique. What happends here to the ICE?

    You recent description of your performance in the hybrid mileage event included something like "I must of fake shifted (FS) 100 times during the event" made me take a closer look at this technique. I knew lifting your foot off the pedal would cause a decrease in RPM'S and thus an increase in fuel efficiency. Am I correct to add, FS also provides a small "boost-charge" to the HV battery in "D" as well as "L"?

    One can shift into "L" prior to braking to slow the vehicle down and to provide an additional boost to the HV battery. One also shifts into "L" after the ICE restarts or shortly before the ICE restarts when the hybrid battery display indicates it is reaching its allowable discharge limits. Naturally if one does not have the hybrid/navigational headunit in their vehicle, it is difficult to determine when this should occur.

    Your thougts?
    Hi Billy

    Over a year ago, I posted the effects of "N" (neutral) coasting in the FEH. My lifetime average is over 45mpg now, and is still improving. On July 20th, I think I proved the techniques I use on a daily basis work. Even though Debbie Katz's SG2 was calibrated to read 7.5% lower than the nav sys MPG average, I calculate that I got over the navi max reading to a 61.8mpg average during the 27 mile MPG Challenge at Hybridfest with her vehicle.

    Your question about "N" coasting with the engine running is a good one. The engine will start any time you exceed 41 mph unless the key is off. This happens in the Challenge video of my drive. I was coasting down a long hill and avoided going over 40mph by shifting to "L" and picked up some regen as a bonus. As I was talking to Debbie, I shifted back to "N" to increase my speed again. Not paying attention while I was explaining to Debbie why I shifted to "L", my speed went above 41mph and the engine started. I quickly shifted back to "L" and the engine kicked off again once I slowed to 40mph. Back to "N" again for coasting.

    With the shifter in "N" and the engine running, the idle is no longer controlled by MG1. This causes the idle to increase and the increase in idle speed makes your instant MPG go higher than gliding in "D". However, "D" gliding involves some regen, and therefore you lose speed much faster. Also, "D" gliding reduces fuel injector output a little. When you FS in "L", the fuel injectors even cut back more, and you get heavy regen. The bottom line is you will maintain your speed longer and get better overall mileage while gliding at higher speeds in "N" with the engine running than you do gliding in "D". I seldom glide in "D" because below 40mph I am in EV and gliding in "N", and above 40mph, I get better overall MPG gliding further in "N" than "D".

    Always pulse with the lowest RPM possible depending on traffic. Glide in "N" in EV and ICE running above 40mph. Use "D" for slowing slow and "L" for slowing faster. Avoid using the brake pedal, but you can boost regen over "L" slowing by applying light brake pedal also. Stay in control of charging and discharging the battery and keep the engine off as much as possible.

    GaryG

  4. #3
    Junior Member
    Join Date
    Apr 2007
    Posts
    0
    Thanks for your input. It is now time to practice gliding in "N" and noting any changes in the scangauge II readings.

    Lets see now. "L" is used for braking, just before or after the vehicle comes out of electric mode. "L" is used as a means to quickly recharge the Hybrid battery in an attempt to quickly regain the ability to go back into electric mode.

    "N" is used for gliding on the flats or in rolling conditions (pulse and glide technique). "N" can be used on longer downhills since there is less "friciton" than when the vehicle is in "D". "N" can keep a vehicle in electric mode faster than 40mph--good for longer downhills.

    "D" is used for uphills, when one is in the pulse phase of "pluse and glide" technique and when one is above 40mph.

  5. #4
    Junior Member
    Join Date
    Oct 2006
    Posts
    0
    Quote Originally Posted by billyk24 View Post
    Thanks for your input. It is now time to practice gliding in "N" and noting any changes in the scangauge II readings.

    Lets see now. "L" is used for braking, just before or after the vehicle comes out of electric mode. "L" is used as a means to quickly recharge the Hybrid battery in an attempt to quickly regain the ability to go back into electric mode.

    "N" is used for gliding on the flats or in rolling conditions (pulse and glide technique). "N" can be used on longer downhills since there is less "friciton" than when the vehicle is in "D". "N" can keep a vehicle in electric mode faster than 40mph--good for longer downhills.

    "D" is used for uphills, when one is in the pulse phase of "pluse and glide" technique and when one is above 40mph.
    Billy, your missing what I'm saying, even in "N", the engine will start when going downhill at 41mph. There is no way the computer will allow EV above 40mph in any gear including "N". You can cut the key-off at any speed in "N", but you said you weren't interested in doing FAS.

    GaryG

  6. #5
    Junior Member
    Join Date
    Apr 2007
    Posts
    0
    Gary, thanks for the update. I have just started to insert "N" as part of my driving routine when "I feel confortable to do so". I'm learning and I need more real world experience to further develop my hybrid driving techniques. Your previous post and information on various sites has been extremely helpful.

    The belief you could go EV above 40mph in "N" can from a poster who will remain nameless.

  7. #6
    Junior Member
    Join Date
    Oct 2006
    Posts
    0
    Quote Originally Posted by billyk24 View Post
    Gary, thanks for the update. I have just started to insert "N" as part of my driving routine when "I feel confortable to do so". I'm learning and I need more real world experience to further develop my hybrid driving techniques. Your previous post and information on various sites has been extremely helpful.

    The belief you could go EV above 40mph in "N" can from a poster who will remain nameless.
    Thanks Billy for the kind words, and I'm glad we got the "N" coasting above 40mph straight. You seemed to catch on to the importance of the Fake Shift (FS) when I mentioned I did it over a hundred times during the MPG Challenge at Hybridfest.

    The battery SoC gauge is very important to get the best MPG in city driving, however, I'll explain what can be done without it. The FEH/MMH charging and discharging is the same in FWD & AWD, but the AWD just has more drag and therefor discharges faster. This will make the EV cycle shorter than the FWD.

    When I drive in EV range, which is anytime I can operate under 40mph, I use a technique where I drain the battery till I get a restart. Now, I can be holding 35-38mph when this happens, or I could drop to any speed below that while coasting in "N". As soon as I get a restart, I begin to immediately shift to "L" and FS (it's best to be above 20mph) so regen packs the battery with a large boost. This will take about 3 seconds of slowing down, but while this is happening, very little fuel is used by the ICE during a FS in "L". Two things will happen with that first FS: The ICE will shutdown or want to shutdown, or you can shift back to "D" and accelerate to your target speed. If the ICE wants to shutdown, and traffic will permit it, let it shutdown and hold EV as long as you can till you get another restart of the ICE. Continue with another first FS like you started and go to your target speed up to 43mph for the last FE in "L" and go EV till you get a drained battery restart.

    I used this technique in the MPG Challenge, and I use this technique everyday in city driving at home. The battery takes a heavier charge at its lowest level, so I take advantage of it. The results is I can drive EV for about 70% of the time and distance. You don't need a battery SoC gauge to use the best techniques I know for the FEH/MMH, if you understand how we use the battery SoC to learn. There are many other technique I use, and I will share as much as I can to help everyone as much as possible.

    The video that will be on CleanMPG of my MPG Challenge may need more explanation to help everyone, so what I was thinking was, a post explaining what I was doing at the time on the time clock of the video may be helpful. Let me know. The video should be posted soon.

    GaryG

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts