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Thread: CVT owners... what is "Idle Neutral Logic"? And what is it like to drive?

  1. #41
    Senior Member Dirk Diggler's Avatar
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    I've never experienced HSA in either of my Mirages. Odd. I previously mentioned my car going backwards on a flat surface in drive but HSA probably had nothing to do with it?



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    Quote Originally Posted by inuvik View Post
    My understanding of CVT's unless it has a electronic disconnect like the Mirage when you are sitting stopped in gear if the belt is engaged it's slipping on the outer edge of the drive pulley. If you let off the brake and the car moves forward with no throttle then the belt has to be slipping while you are stopped because the drive belt is engaged.
    How have we ruled out the torque converter somehow?

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    Quote Originally Posted by Dirk Diggler View Post
    I've never experienced HSA in either of my Mirages. Odd. I previously mentioned my car going backwards on a flat surface in drive but HSA probably had nothing to do with it?
    Does a CVT vehicle have HSA? I figured it was only for annoying 5 speed drivers.


    Quote Originally Posted by skyblue View Post
    How have we ruled out the torque converter somehow?
    Does a CVT have a torque converter? I figured a torque converter was only for annoying multispeed / geared transmissions.

        __________________________________________

        click to view fuel log View my fuel log 2020 Mirage ES 1.2 manual: 42.4 mpg (US) ... 18.0 km/L ... 5.6 L/100 km ... 50.9 mpg (Imp)


  4. #44
    Quote Originally Posted by 7milesout View Post
    Does a CVT vehicle have HSA? I figured it was only for annoying 5 speed drivers.


    Does a CVT have a torque converter? I figured a torque converter was only for annoying multispeed / geared transmissions.
    Yes and yes.

    While I haven't seen a cvt in a car work I can't believe the belt would slip without causing immediate damage.

    Different animal but my 2020 Kawasaki has a cvt. The belt has constant tension and does not slip on the clutches when it's not moving regardless of being in drive or neutral and stopped. It's got another centrifical wet clutch on the secondary(driven clutch)shaft inside the actual gearbox.

    Where as my old Polaris, the primary clutch would open up at idle wide enough that the belt wouldn't touch the outer edges of the clutch but it would ride on a bearing on the center of the primary so the belt wouldn't be slipping while stopped in gear at idle.

    I'd like to assume a belt driven cvt in a car works similarly to the Kawasaki, not the Polaris or at least the same idea. And cars have a torque converter(fluid coupler).
    Last edited by Fummins; 10-07-2021 at 01:55 PM.
    Mirage videos:

        __________________________________________

        click to view fuel log View my fuel log 2014 Mirage SE wussie cvt edition. 1.2 automatic: 37.7 mpg (US) ... 16.0 km/L ... 6.2 L/100 km ... 45.3 mpg (Imp)


  5. #45
    Moderator inuvik's Avatar
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    Quote Originally Posted by Fummins View Post
    Yes and yes.

    While I haven't seen a cvt in a car work I can't believe the belt would slip without causing immediate damage.

    Different animal but my 2020 Kawasaki has a cvt. The belt has constant tension and does not slip on the clutches when it's not moving regardless of being in drive or neutral and stopped. It's got another centrifical wet clutch on the secondary(driven clutch)shaft inside the actual gearbox.

    Where as my old Polaris, the primary clutch would open up at idle wide enough that the belt wouldn't touch the outer edges of the clutch but it would ride on a bearing on the center of the primary so the belt wouldn't be slipping while stopped in gear at idle.

    I'd like to assume a belt driven cvt in a car works similarly to the Kawasaki, not the Polaris or at least the same idea.
    I have seen both designs on a cvt and I'm really not sure which method the Jatco CVT7 uses but if there wasn't a issue with sitting at a stop engaged in gear then what's the reason for idle neutral logic? If it's important for the transmission to go into neutral at stops then the only way to make sure it does is put it into neutral manually which I do.

        __________________________________________

        click to view fuel log View my fuel log 2015 Mirage ES 1.2 automatic: 40.5 mpg (US) ... 17.2 km/L ... 5.8 L/100 km ... 48.6 mpg (Imp)


  6. #46
    From what I read(I'll have to search for it again), the idle neutral logic is used to reduce engine load while stopped. Basically for fuel efficiency. Seems legit? Maybe I'm wrong and the secondary pulley is locked to to the ring and pinion? I tossed out the cvt I had tore open a while back... Damnit. I'll have to open up another one.
    Mirage videos:

        __________________________________________

        click to view fuel log View my fuel log 2014 Mirage SE wussie cvt edition. 1.2 automatic: 37.7 mpg (US) ... 16.0 km/L ... 6.2 L/100 km ... 45.3 mpg (Imp)


  7. #47
    Moderator inuvik's Avatar
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    Quote Originally Posted by Fummins View Post
    From what I read(I'll have to search for it again), the idle neutral logic is used to reduce engine load while stopped. Basically for fuel efficiency. Seems legit? Maybe I'm wrong and the secondary pulley is locked to to the ring and pinion? I tossed out the cvt I had tore open a while back... Damnit. I'll have to open up another one.
    I've thought that it might be for fuel economy purposes also but if that was the case why are the conditions for it to activate so restrictive? Dunno

        __________________________________________

        click to view fuel log View my fuel log 2015 Mirage ES 1.2 automatic: 40.5 mpg (US) ... 17.2 km/L ... 5.8 L/100 km ... 48.6 mpg (Imp)


  8. #48
    My guess on the not going into neutral automatically with the signal light on is to prevent delayed engagement while pulling into traffic?

    As for the no idle logic with the ac or other significant loads, I dunno?

    I wonder if vehicles with auto start/stop disengage with the signal light on?

    I've noticed mine goes into neutral fairly often on it's own. It's got a bit of a delay between letting off the brake and it actually kicking into drive. It'd be nice to talk to an enginerd who knows how these things are designed to work and why.
    Mirage videos:

        __________________________________________

        click to view fuel log View my fuel log 2014 Mirage SE wussie cvt edition. 1.2 automatic: 37.7 mpg (US) ... 16.0 km/L ... 6.2 L/100 km ... 45.3 mpg (Imp)


  9. #49
    Moderator inuvik's Avatar
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    Then there is is section in my owner's manual page 5-39 which describes putting it into neutral:

    For short waiting periods, such as at traffic
    lights, the vehicle can be left in selector lever
    position and held stationary with the service
    brake.
    For longer waiting periods with the engine
    running, place the selector lever in the “N”
    (NEUTRAL) position and apply the parking
    brake, while holding the vehicle stationary
    with the service brake.

        __________________________________________

        click to view fuel log View my fuel log 2015 Mirage ES 1.2 automatic: 40.5 mpg (US) ... 17.2 km/L ... 5.8 L/100 km ... 48.6 mpg (Imp)


  10. #50
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    Quote Originally Posted by Fummins View Post
    It'd be nice to talk to an enginerd...
    Hey watch it. I resemble that remark.

    I thought it might be cool and possible to drive into ETACS, and activate the idle stop that some countries have for 5-speeds. However, in my enginerding mind, I'm guessing that variation will have a different starter and a different battery. No telling what other changes there may be. And for the scant little fuel savings there would be, I'll not worry about it.

    I do my darndest not not be sitting idle at the car, even at traffic lights (but of course it happens). I avoid it by starting to slow down way early for congestion due to traffic lights. Many times it is clearing up just as I'm getting to it, so it works out good. Make the automatic idle stop of low value.


        __________________________________________

        click to view fuel log View my fuel log 2020 Mirage ES 1.2 manual: 42.4 mpg (US) ... 18.0 km/L ... 5.6 L/100 km ... 50.9 mpg (Imp)


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