Page 1 of 2 12 LastLast
Results 1 to 10 of 19

Thread: Why idle neutral logic with a torque converter?

  1. #1
    Senior Member MightyMirageMpg's Avatar
    Join Date
    Apr 2016
    Location
    wi
    Country
    United States
    Posts
    489
    Thanks
    305
    Thanked 196 Times in 119 Posts

    Why idle neutral logic with a torque converter?

    Quote Originally Posted by IchabodCrane View Post
    I had it in my '14 CVT Mirage and now in my '17 CVT. It works flawlessly every time. It could be that the CVT having a torque converter absorbs some of the delay during engagement.
    Perhaps a more relaxed pace coupled with a judicial application of throttle will ease the transition.
    If one cannot adjust their driving style to suit the vehicle they're in it's no fault of the vehicle itself.
    This might sound silly but why does the cvt transmission have a torque converter and neutral idle logic?



  2. #2
    Moderator Eggman's Avatar
    Join Date
    Sep 2015
    Location
    Ohio ☼
    Country
    United States
    Posts
    2,900
    Thanks
    1,980
    Thanked 692 Times in 516 Posts
    Quote Originally Posted by MightyMirageMpg View Post
    This might sound silly but why does the cvt transmission have a torque converter and neutral idle logic?
    Just guessing:
    1. To allow the engine to continue to run at a stop.
    2. To save fuel while at idle.

    The neutral idle logic was discussed. I'll try to find it.

        __________________________________________

        click to view fuel log View my fuel log 2015 Mirage ES 1.2 manual: 49.0 mpg (US) ... 20.8 km/L ... 4.8 L/100 km ... 58.8 mpg (Imp)


  3. The Following User Says Thank You to Eggman For This Useful Post:

    BostonJellyBean (01-18-2017)

  4. #3
    Moderator Eggman's Avatar
    Join Date
    Sep 2015
    Location
    Ohio ☼
    Country
    United States
    Posts
    2,900
    Thanks
    1,980
    Thanked 692 Times in 516 Posts

        __________________________________________

        click to view fuel log View my fuel log 2015 Mirage ES 1.2 manual: 49.0 mpg (US) ... 20.8 km/L ... 4.8 L/100 km ... 58.8 mpg (Imp)


  5. #4
    Senior Member MightyMirageMpg's Avatar
    Join Date
    Apr 2016
    Location
    wi
    Country
    United States
    Posts
    489
    Thanks
    305
    Thanked 196 Times in 119 Posts
    Quote Originally Posted by Eggman View Post
    Just guessing:
    1. To allow the engine to continue to run at a stop.
    2. To save fuel while at idle.

    The neutral idle logic was discussed. I'll try to find it.
    I like #1. It makes the most sense.

    I guess i *presumed* the cvt went into neutral everytime you let off the throttle. The versa i drove (different software obviously) didn't feel like it engine braked at all.

    I also thought the transmission would be capable of 1mph and utilize some kind of clutch for efficiency
    Last edited by MightyMirageMpg; 01-18-2017 at 01:08 AM. Reason: proper wording

  6. #5
    Moderator Eggman's Avatar
    Join Date
    Sep 2015
    Location
    Ohio ☼
    Country
    United States
    Posts
    2,900
    Thanks
    1,980
    Thanked 692 Times in 516 Posts
    Quote Originally Posted by MightyMirageMpg View Post
    I like #1. It makes the most sense.

    I guess i *presumed* the cvt went into neutral everytime you let off the throttle. The versa i drove (different software obviously) didn't feel like it engine braked at all.

    I also thought the transmission would be capable of 1mph and utilize some kind of clutch for efficiency
    Yeah it's crazy I think the CVT in the Mirage is also used in some Nissan models. I wonder if it's used in the Versa? I think it is.

    I know what you mean about engine braking. Our Fusion does this. I think it doesn't do deceleration fuel cut-off - another thing I learned from this forum.

        __________________________________________

        click to view fuel log View my fuel log 2015 Mirage ES 1.2 manual: 49.0 mpg (US) ... 20.8 km/L ... 4.8 L/100 km ... 58.8 mpg (Imp)


  7. The Following User Says Thank You to Eggman For This Useful Post:

    MightyMirageMpg (01-18-2017)

  8. #6
    Moderator inuvik's Avatar
    Join Date
    May 2015
    Location
    Coos Bay, OR
    Country
    United States
    Posts
    1,650
    Thanks
    1,279
    Thanked 541 Times in 406 Posts
    Quote Originally Posted by MightyMirageMpg View Post
    I like #1. It makes the most sense.

    I guess i *presumed* the cvt went into neutral everytime you let off the throttle. The versa i drove (different software obviously) didn't feel like it engine braked at all.

    I also thought the transmission would be capable of 1mph and utilize some kind of clutch for efficiency
    This is the primary reason I shift into neutral if I'm going to be idling for more than 10 seconds. This way I know for sure the CVT is disengaged. Once you get into the habit it's no different then idling in neutral at a stop with a manual transmission.

        __________________________________________

        click to view fuel log View my fuel log 2015 Mirage ES 1.2 automatic: 40.7 mpg (US) ... 17.3 km/L ... 5.8 L/100 km ... 48.9 mpg (Imp)


  9. The Following User Says Thank You to inuvik For This Useful Post:

    MightyMirageMpg (01-18-2017)

  10. #7
    Senior Member MightyMirageMpg's Avatar
    Join Date
    Apr 2016
    Location
    wi
    Country
    United States
    Posts
    489
    Thanks
    305
    Thanked 196 Times in 119 Posts
    Quote Originally Posted by Eggman View Post
    Yeah it's crazy I think the CVT in the Mirage is also used in some Nissan models. I wonder if it's used in the Versa? I think it is.

    I know what you mean about engine braking. Our Fusion does this. I think it doesn't do deceleration fuel cut-off - another thing I learned from this forum.
    I always preferred manual transmission so never really researched automatics in general. Now I'm getting older and think i should've got the cvt. Lol

  11. #8
    Senior Member IchabodCrane's Avatar
    Join Date
    Apr 2014
    Location
    Thunder Bay, ON. CA
    Country
    Canada
    Posts
    508
    Thanks
    21
    Thanked 181 Times in 116 Posts
    A typical CVT lets go of the belt at idle and must engage (grab) it again to start moving. During engagement the belt slips against the sheaves. This slipping causes wear. In a typical CVT with a rubbber composite belt that's easy to change when worn this is an acceptable feature. In automotive CVT's the belt is woven steel. Slippage in this system will cause excessive heat and wear to the point of failure very quickly. to circumvent this the belt is always kept in proper tension in full contact with the sheaves so a torque converter is required to handle the slippage required for idling in gear and progressive engagement (slippage) to get moving again. Without this the CVT is not feasible in automotive applications.
    The neutral idle logic technically put the trans in neutral relieving engine load for economy at idle while relieving stress on the torque converter. The latter is necessary as the torque converter is very small for weight savings and can overheat quickly. As stated previously and in the owner's manual, it's a good idea to shift into neutral for prolonged stops at idle.
    Last edited by IchabodCrane; 01-18-2017 at 01:42 AM.
    Will weld for beer.

        __________________________________________

        click to view fuel log View my fuel log 2014 Mirage SE 1.2 automatic: 45.3 mpg (US) ... 19.3 km/L ... 5.2 L/100 km ... 54.5 mpg (Imp)


  12. The Following User Says Thank You to IchabodCrane For This Useful Post:

    MightyMirageMpg (01-18-2017)

  13. #9
    Senior Member MightyMirageMpg's Avatar
    Join Date
    Apr 2016
    Location
    wi
    Country
    United States
    Posts
    489
    Thanks
    305
    Thanked 196 Times in 119 Posts
    Quote Originally Posted by IchabodCrane View Post
    A typical CVT ... In a typical CVT with rubber .........
    Do you mean another auto application or a different application all together?
    Last edited by MightyMirageMpg; 01-18-2017 at 01:59 AM.

  14. #10
    Senior Member
    Join Date
    Nov 2014
    Location
    Netherlands
    Country
    Netherlands
    Posts
    166
    Thanks
    4
    Thanked 17 Times in 15 Posts
    DAF used to have a CVT with rubber belts in the seventies/eighties for its cars. But I think he meant mopeds, snowmobiles and the like.

    I have not found anything in the owners manual that indicates that it recommends shifting to neutral at prolonged stops. Idle logic makes that redundant, so I do not see why it is needed. I will have another look.



  15. The Following User Says Thank You to RodeRoNL For This Useful Post:

    MightyMirageMpg (01-18-2017)

Posting Permissions

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