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

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The Mitsu press release from the New York Auto Show Mirage launch this morning mentioned a feature of the CVT transmission that I hadn't seen before: idle neutral logic.

Can anyone tell me what this is?

I'm assuming it means that the transmission goes into neutral whenever you stop, and that's the reason why the CVT also has Hill Start Assist so you don't roll backwards when releasing the brakes on a grade.

If that's what it is, it must be another fuel saving feature to reduce load on the engine when stopped, rather than remaining in gear, constantly trying to drive the car forward while your foot is on the brake.

Is that about right?

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Update: see post #22 for the list of conditions when the feature is active or not.

According to Mitsubishi Service sheet 411 (2012) you are absolutely right:

Idle-Neutral Logic

This system shifts the transmission into neutral when the vehicle comes to a complete stop and the brakes are applied. By shifting into neutral, Idle Neutral Logic lessens the amount of power needed to turn the transmission thus reducing drag on the engine. Less power equals less gas required and conserves fuel.

Source: http://touch.mservice411.com/c/idle-neutral-logic

Aha. Merci, monsieur.

On to part two (added to the thread title):

What is it like to drive?

Does it stay in neutral and wait until you press the accelerator again before going back into gear? Doesn't that create a delay in starting up compared to a "regular" automatic transmission? Is it a smooth transition?

Will the car "creep" forward when you let your foot off the brake, or do you have to give it a little gas?

Enquiring minds want to know...

During my test-drive I noticed that there was almost no 'creeping'. Neither in 'forward' nor in 'reverse'.

I wonder if, as a fuel economy modification, one could setup a switch to engage this neutral logic at will? I would also wonder if that would do any damage to the transmission due to lack of lubrication as is the case for some automatic transmissions...

(I have to admit I wondered the same thing.)

So that explains why when I release the brake, the car surges forward instead of slowly creeping like other TC autos.

But so far seems like it has strange engagements. Let me test it out later and get back to you guys =)

I have never noticed my Mirage creep forwards, in fact it does seem to be a little more laggy off the line then other auto's including my CVT Outlander. Hill Assist you can definitely feel it holding the brakes.

but it doesn't seem to kick in everytime. sometime during a jam, after a few stop-gos, then stop at traffic light, it will not work.

It could be part of the "logic" that it doesn't go to neutral every time the car stops if it has been started/stopped several times in a short amount of time/distance.

Some hybrids and engine stop/start systems are programmed like this: they will shut the engine down for the initial stop, but if you move ahead again (engine restart) only a short distance, it may not shut down again until you've gone above a certain speed threshold. Otherwise the feature may become annoying to the driver.

The neutral-to-start engagement of the Mirage CVT may be programmed the same way for the same reason.

I'm interested in seeing this feature first hand.

Paying attention driving today and it is definitely not always happening. It was creeping at the roundabout but not at the lights. My current hunch (I will need to do some testing down the road) is that it is time delayed. A quick stop (roundabout, street corner etc.) it doesn't engage, slightly longer stop (lights, stop sign etc) it does.

Thanks, Ant! Once it has engaged neutral, how do you find the next startup? Smooth? Jerky? Depend on amount of throttle given?

It will jerk slightly

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Originally Posted by Daox

I wonder if, as a fuel economy modification, one could setup a switch to engage this neutral logic at will? I would also wonder if that would do any damage to the transmission due to lack of lubrication as is the case for some automatic transmissions...

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As far as I can tell our Kiwi market CVT Mirage doesn't have Neutral Logic so I have taken to moving the gear selector into Neutral when it becomes obvious that the car will be stopped for more than a few seconds. When in slow moving traffic simply pulling the selector back into Drive is enough to make the car creep forward.

So, that makes me wonder if Neutral Logic is switchable in software ? It seems unlikely to me that Mitsi would go to the trouble of fitting different ECUs, or developing different programming for a universal ECU for what is designed to be a basic world-market car.

Cheers
Flange

When the cvt starts from a dead stop it feels exactly the same as a manual with a noticeable progressive clutch engagement phase flowing seamlessly into cvt operation.
You get the same feel with neutral logic when leaving a light.

Ichabod: can you tell when idle neutral is active? If so, how? I didn't drive the CVT long enough to be able to tell definitively.

Quote:

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Originally Posted by Flange

So, that makes me wonder if Neutral Logic is switchable in software ? It seems unlikely to me that Mitsi would go to the trouble of fitting different ECUs, or developing different programming for a universal ECU for what is designed to be a basic world-market car.

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I think it's all in the programming. Mitsu have made a bunch of other country-specific changes to the car for cost, fuel economy, comfort, handling & regulatory reasons.

Metro..

One way to tell the diff is to stop on level surface apply brake, shift to neutral, wait a couple sec, put car in drive. You will feel an immediate engagement and the car will creep if you let off brake..
If you repeat this scenario without shifting to neutral but holding brake while stopped for a few sec in drive, when you release the brake the car will sit static until accellerator is applied at which time you will feel the progressive clutch engagement.
So in my experience whenever I feel that telltale progressive clutch engagement I know it has come out of neutral idle logic.

I noticed it from the first time I drove it. I figure that it is a cost savings thing for Mitsubishi. It seems like it is something that is supposed to be on cars that have stop-start. Instead of changing the transmission programming because the cars in the USA do not have stop-start, they just came up with a catchy name to make it seem like a feature. It almost reminds me of my old Smart Fortwo. Those cars have an automated manual transmission and it put itself into neutral on every stop. This one only does it when you have been stopped for more than a few seconds. If you move quickly from the brake to the gas, there is a small jerk when the transmission engages. I can see how reviewers and even people taking it for a long test drive would be put off by it. I am used to it, but it does annoy me at times because I expected a CVT to be a lot smoother.

I've noticed the same thing with the manual. It will roll to a perfect stop even on a slight uphill, but if I move the car at all from the point where it stops, it will begin to roll back.

On the matter of cvt, I'm pretty sure it's still torque converted to reduce wear on what i would assume is a push belt, Hopefully someone can correct me if I'm mistaken, I've only driven the 5MT but I'm quite curious.

Edit: after some more research, it IS a Jatco cvt (Nissan) which features a lock-up torque converter, and it's rated for double the horsepower of the 3A92 engine, so you probably couldn't get the belt to slip, as the transmission would know that the car is stationary and the torque converter would just warm up a little bit without turning the drive pulley 3000 RPM isn't getting very near peak torque yet so the risk of the push belt slipping is negligible unless for some reason it reduces clamping force on the belt when car is stationary. I doubt this would be the case however as there is no benefit to it. It is also dual-range, which provides an extremely wide ratio spread, enough to make 5mt owners like myself jealous of the minimum speed (and minimum highway rpm)

MetroMPG linked a diagram on this other thread:
http://mirageforum.com/forum/showthr...video-diagrams

I think you have to be at a full stop cuz i brake uphill then let go and it rolls back. If i stop fully then its a different story.

This all makes perfect sense. When I am coming to a stop in heavy traffic at a traffic signal, the car lurches forward after I have already came to a complete stop. That must be the gearbox shifting into neutral to save fuel. Then it does take a few seconds (especially if you mash the pedal) to "spin up" and engage the transmission into gear. Its really ingenious if you ask me.

I don't care much for the Idle Neutral Logic because of all the conditions that must be present in order for it to activate so I put the transmission in neutral if I'm going to be stopped for more than 15 seconds. That way I know it's in neutral.


Idle neutral control is started when all of the following conditions are fulfilled. However, during idle neutral control, idle neutral control is stopped when any of the following conditions is not met.

Driving environment: Flat road or road with mild grade

Selector lever position: *D* position

Vehicle speed: 0 km/h (0 MPH)

Accelerator pedal position: 0.0/8

Brake pedal: Depressed

Engine speed: Idle

Turn signal lamp/hazard signal lamp: Not activated

Idle neutral control stops or is prohibited when the TCM and ECM detect that the vehicle is in one of the following conditions.

- Engine coolant temperature and CVT fluid temperature are the specified temperature or more, or the specified temperature or less.

- When a transaxle malfunction occurs.

- When the vehicle detects DTC and is in the fail-safe mode.

- When idle speed increases due to heavy electric load*.

*: When any one of rear window defogger switch, A/C switch, headlamp, fog lamp is turned ON or when the steering wheel is operated.

Thanks for that list, inuvik. There are some interesting conditions in there.

INL definitely still activates when my '17's A/C is on and running.

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Originally Posted by MetroMPG

Thanks for that list, inuvik. There are some interesting conditions in there.

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I understand Mitsubishi's attempt to place the CVT in Neutral because in a CVT if it's not in neutral then while you are sitting there the belt is slipping against the primary drive pulley. Slipping=Wear. But if you're sitting in traffic with the A/C on the Idle Neutral Logic is never going to activate. Move the steering wheel, have your turn signal on etc... not going to happen. The "clunk or lurch" that most people feel at a stop is the CVT moving into the low range and the corresponding ratio change. Is this a potential life shortener of the CVT? I don't know but I do know that there must be something to it because the owner's manual page 5-42 it says this about placing the transmission in Neutral: "At this position, the transmission is disengaged. It is the same as the neutral position on a manual transaxle and should be used when the vehicle is not moving for an extended length of time during driving, such as in a traffic jam."

Update:

Idle Neutral Logic appears to be a JATCO programming function because the same information appears in the Nissan CVT information. Also, found an interesting link that refers to how this CVT operates.

https://www.atsg.us/atsg/blog/thejf0...thejf015ecvt7/

Yea, pretty sure mine still activates too when the AC is on. I think maybe thats a difference between the '14 and '17 model?

Okay, I just read this too late sorry. Also, that makes sense that the lurch is the gear ration switching. Questions, is putting the car in park going to do the same at putting in neutral as far as decreasing wear goes? I mean the only difference is the brakes are applied right? I'm just not that versed in CVT transmissions.

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Originally Posted by Dabullfrog91

Okay, I just read this too late sorry. Also, that makes sense that the lurch is the gear ration switching. Questions, is putting the car in park going to do the same at putting in neutral as far as decreasing wear goes? I mean the only difference is the brakes are applied right? I'm just not that versed in CVT transmissions.

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The short answer is "yes". Although I wouldn't use Park when operating on the road

Attachment 9898The idle neutral logic in my 2017 G4 SE kicks in 85% of the time. You can clearly tell when sitting at idle if its in neutral or not and when you let off the brake you feel it shift back in gear if it was. My 2015 did not utilize the idle neutral logic near as muc as my 2017 does and my 2017 seems to most always do it. The transmissions in the 2017s seem much more sorted out and overall drivetrain smoothness is better. I loved my 2015 but the 2017 seems much more refined. When I drive my co workers 2015 and then mine you can feel the difference with the transmission. Anytime I come to a complete stop mine will go into neutral now if I let off brake then edge forward and stop it will stay in drive. Or if im driving very slow then stop it will stay in drive. But any normal driving and coming to a stop light it always kicks in on mine, very smart Mitsubishi. I really like that I can tell in my 2017 when it is using idle neutral logic by the sensation when letting of the brake you feel it shift into gear again lets me know its working.

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Originally Posted by Mirage ES Navi

The transmissions in the 2017s seem much more sorted out and overall drivetrain smoothness is better. I loved my 2015 but the 2017 seems much more refined.

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Definitely agree.

I hate this stupid idiot logic thing. If you are on the 210 heavy traffic in Pasadena CA, makes you want to take it in for a trany change! But then I can put it in D5 and it rocks. Even the engine breaks helps keep speed but not use the brakes to rock the car back and forth

Hi, it appears the Idle Neutral Control disabled on my 2015 Indonesian Mirage. Is simple ETACS coding will activate it or there are more hardware to be installed first?
Attachment 12412

My fiancee G4 is smoother. Hope that doesnt translate to way more longevity vs my 2014 DE lol.

Im not a fan, Ive had my ride go backwards on a mostly flat survace at a drive thru. It went back until I hit the gas. Its only done this twice and my hill assist works on steep hills, but still unnerving. Wish could switch it off like the auto climate control compressor.

Quote:

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Originally Posted by Dirk Diggler

Im not a fan, Ive had my ride go backwards on a mostly flat survace at a drive thru. It went back until I hit the gas. Its only done this twice and my hill assist works on steep hills, but still unnerving. Wish could switch it off like the auto climate control compressor.

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I noticed mine did the same thing 3 times in a row this morning. I hold the brake pedal harder than in other cars cause I don't want that lurch forward like a retard feeling I get sometimes in the work Mirages. I figured mine was in neutral cause when I was stopped it was running pretty quiet and smooth unlike when you first put it in gear and it gets a bit of the shakes. When I let off the brake it rolled back a little til I hit the gas. I didn't have the ac on but had headlight and fogs on. I don't know how far it would have rolled but wonder what the parameters are for the hillstart brake assist to kick in.

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Originally Posted by Fummins

but wonder what the parameters are for the hillstart brake assist to kick in.

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Mitsubishi Innovation: HSA (Hill Start Assist)

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Originally Posted by Mitsubishi | Innovation

HSA (Hill Start Assist)

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This system prevents vehicles rolling backwards and makes hill starts easier by holding the braking force during the time when the driver is moving his/her foot from the brake pedal to the accelerator pedal in order to start the vehicle on a steep road.

When the system determines that the vehicle is stopped on a steep road from the information of various sensors and the ECUs, the system will hold the braking force after the driver releases the brake pedal until the driver depress the accelerator pedal (for a maximum of two seconds). The system will reduce the braking force in accordance with the operation of the accelerator by the driver and the engine torque that is generated.

• HSA also functions when the vehicle is reversing up a steep road.

https://mirageforum.com/forum/attach...9&d=1484475405

https://mirageforum.com/forum/attach...0&d=1484475425

• Depending on the road surface conditions, the vehicle may roll backwards.

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At least that's what Mitsubishi says about it.

Just discovered this thread. I didn't even realize this was a feature, I thought it was just another quirk. I kind of like the little 'jerk' motion upon startup. Might not be cool or sporty but certainly adds personality. At longer lights I don't notice it as much because I'll turn the engine right off, as long as I don't need to be signalling. At shorter lights though there is a noticeable jump when first accelerating.

I'm not a big fan of it due to the conditions that have to met before it will function. This is why I manually put mine in neutral at almost every stop, that way I know it's in neutral for sure. Otherwise you're just sitting there with the belt slipping while you are stopped.

Are you sure that's how they work? I can't imagine the belt actually slips while stopped. I can't fact check atm though.

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Originally Posted by Fummins

Are you sure that's how they work? I can't imagine the belt actually slips while stopped. I can't fact check atm though.

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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.