Why a neutral position on Hybrids' CVT transmission?

[mpm235]

Hello Friends,

I've just thought of something. Why have Toyota put a Neutral position in the CVT transmissions of Hybrids? When all us Hybrid drivers know that you must never ever ever ever put it in Neutral, because it flattens the HSD Battery. Leaving you up a certain well known waterway without an instument of propulsion? Just a thought, cheers, Mark.

[RickyC]

There are situations where you need to move the car by hand.  Without a N position how can you do it?  

In normal drive N should never be used.

[Cyker]

It makes even less sense when you realize N doesn't even do anything - It cuts power to the motors but everything is still connected together, unlike N in a normal gearbox, which physically disconnects the drivetrain from the wheels (Due to the way the toyota hybrid system is, it's physically impossible to mechanically disconnect the drivetrain from the wheels)

 

I can only assume it's a legal requirement, even if it doesn't really do anything.

[RickyC]

I agree that everyting remains connected and electric motors will rotate when wheels do.  It's not a case that Toyota explicitly indicates that car must be towed with front wheels not in contact with road.  

But if the car has technical problems and can't move by itself you need a N postion that allows you to push the car.

In the same way there are some car wash tunnels where a conveyor belt moves the car while washing brushes don't move.  In this case you can't leave the car in P but it must be left in N ( being carefuli that SOC is high 😞 before entering the tunnel )

[Haliotis]

Excuse my ignorance, but what is SOC - I can only think of Scene Of Crime🤠

[TonyHSD]

6 minutes ago, Haliotis said:

Excuse my ignorance, but what is SOC - I can only think of Scene Of Crime🤠

That’s sounds almost correct. 
It’s usually a state of charge on the Battery. SOC 
For the N it is there when your car goes bang and your hybrid system malfunction happens the car can switch to N and slowly comes to a complete stop. 
Actually if you dig deeper into transmission you may realise that all transmission inside gears are rotating together with the wheels similar to hybrids and electric cars. The difference is there are no permanent magnets motors and no risk of fire. 
If it happens to slow down your hybrids in N you can still hear the whining from the motor, but not as pronounced. 👍

[Haliotis]

I have just been on website - www.Toyota-tech.eu - there is a lot of info on there, but the dire warnings definitely suggest, “If you don’t know what you are doing, don’t touch”.   There are warnings to ‘wear insulated gloves’, ‘not to work on car without removing the service plug grip’ , ‘wait at least 10 minutes for the high voltage capacitor to discharge….’ , keep the removed service plug grip in your pocket to prevent other technicians from accidental installing it while you are working on the vehicle’ , ‘place a “HIGH VOLTAGE WORK IN PROGRESS. DO NOT TOUCH” sign, in order to prevent other technicians accidentally reconnecting the power while work is in progress’.

Wow! As EVs become evermore common, how long will it be before we hear of a technician being seriously injured, or worse?  Certainly not a working environment where one can be distracted from the job in hand.  

DIY mechanics: Hang up your spanners! 

[Corollanutter]

1 hour ago, Haliotis said:

I have just been on website - www.Toyota-tech.eu - there is a lot of info on there, but the dire warnings definitely suggest, “If you don’t know what you are doing, don’t touch”.   There are warnings to ‘wear insulated gloves’, ‘not to work on car without removing the service plug grip’ , ‘wait at least 10 minutes for the high voltage capacitor to discharge….’ , keep the removed service plug grip in your pocket to prevent other technicians from accidental installing it while you are working on the vehicle’ , ‘place a “HIGH VOLTAGE WORK IN PROGRESS. DO NOT TOUCH” sign, in order to prevent other technicians accidentally reconnecting the power while work is in progress’.

Wow! As EVs become evermore common, how long will it be before we hear of a technician being seriously injured, or worse?  Certainly not a working environment where one can be distracted from the job in hand.  

DIY mechanics: Hang up your spanners! 

However, the voltages in hybrids are no higher (and often lower) that those in the household AC mains. The difference is that it is DC rather than AC - and there are differring schools of thought over which is the more dangerous (it depends on many things..). TBH, this is the normal problem (and the real fear that some people have) in working with electrics - you can't see it. You just need to develop an electricans mindset and working practices.

[Haliotis]

39 minutes ago, Corollanutter said:

However, the voltages in hybrids are no higher (and often lower) that those in the household AC mains. The difference is that it is DC rather than AC - and there are differring schools of thought over which is the more dangerous (it depends on many things..). TBH, this is the normal problem (and the real fear that some people have) in working with electrics - you can't see it. You just need to develop an electricans mindset and working practices.

The info given relates directly to the C-HR hybrid.  The HV Battery has a nominal voltage of 201.6 VDC and the inverter/converter raises this to a max of 600 VDC. It also convert DC to AC and back.  When you read the info., it is clear that the warnings are for good reason.

I am familiar with, and have worked on, household domestic circuits and on 3-phase industrial installations.  But the hybrid circuitry and safety requirements, along with minimal availability of detailed procedures as far as the average owner is concerned, and with all my experience of working in electrical and mechanical engineering, I would be extremely reluctant to get involved in the workings of my C-HR.

[Cyker]

TBH it's not that much worse than the current state of things IMHO. Cars are already dangerous anyway  - Plenty of opportunities to lose a finger, or triggering a spark around fuel vapour, and then there's things like Common Rail diesels which run their fuel rail at around thirty *thousand* PSI - That's enough to cut your arm off, or inject diesel directly into your veins like a Star Trek hypospray!  

It's just more to add to the pile of be sensible, don't get complacent and respect what you're working on!