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Yaris hybrid as a motorhome towcar?


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4 minutes ago, Mick F said:

Yes, we know all that.

Tow a normal car, and the clutch and gearbox turn. The input shaft and lay gears also, so that means all the gears turn though without one of the gears being selected for output of course.  In neutral, everything still turns.

What's the difference with a hybrid powered down and in neutral?

That is the question.

Mick.

Read my post above and the link to the wiki, as i said a manual box it basically a oil bath with no pump

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Sorry, I still don't get it.

The link said that in N the Battery will drain.  This is referring to running the car "normally" in neutral as in N the Battery isn't charged.

I'm saying turn everything off but remain in N.  Battery isn't even in circuit when the power is off, in fact, nothing is in circuit with the power off so nothing can drain.

Isn't the "gearbox" in a Hybrid sitting in oil?  Why can't it be rotated indefinitely when completely powered down?

Mick.

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Yes the planetary gear set and the differential are sitting in oil, same as manual gearbox. 

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2 hours ago, TonyHSD said:

Yes the planetary gear set and the differential are sitting in oil, same as manual gearbox. 

So what's the issue about towing a Hybrid in neutral with the power/generation switched off?

Mick.

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4 hours ago, TonyHSD said:

Yes the planetary gear set and the differential are sitting in oil, same as manual gearbox. 

I doubt it, sitting in oil wastes energy. The hybrid gear set has an oil pump. Even the 1970s Rover SD1 gearbox had an oil pump and you could only tow them with the propshaft removed!

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Up until a few years ago, we had a Renault Clio.  Owned since brand new in 2001.  Sold in 2017.

The handbook said you couldn't tow them and had to uplift.  Since sold and we obviously no longer have the handbook to use as evidence.

I've seen Clios towed behind campervans, so what Renault say and what is done, are two different things.  I cannot believe that a Rover SD1 cannot be towed without removing the propshaft despite what people might have said.

Mick

 

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1 hour ago, Mick F said:

I cannot believe that a Rover SD1 cannot be towed without removing the propshaft despite what people might have said.

Details are in the car manual and also mentioned in the Haynes manual:

"Manual gearbox models must not be towed with the rear wheels on the ground unless the propeller shaft has been disconnected …."

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Ok.  I give in! 😀

.................. even though with a Clio the handbooks said you couldn't, but from experience, you can.

It doesn't answer the question regarding Toyota Hybrids though.

Mick.

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17 minutes ago, Mick F said:

Ok.  I give in! 😀

.................. even though with a Clio the handbooks said you couldn't, but from experience, you can.

It doesn't answer the question regarding Toyota Hybrids though.

Mick.

Of course you can tow the cars but you have a high chance of gearbox damage - the further you tow, the more likely the damage. I think this may answer the hybrid issue as the gearbox also relies on an oil pump.

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Transmission drain plug is at level with drive shafts and Differential gear definitely is sitting in oil, and when it’s spinning while car is moving sends oil to top of the bell housing, there are some specifically made ‘oil banks’ as Toyota called them to hold the oil and make it dripping onto other gears and bearings. There is also an oil pump connected with driveshaft to the ring gear which means that if the car moves no matter how is propelled the oil pump will create pressure to the oil system in the transmission. On the rear there is water pump for inverter coolant and the MG1 and MG2 stators, and here is the problem probably, because this pump is electric will not work unless the car is in Ready mode and  will not be able to cool down either mg1/mg2 and inverter. What happens actually when car is in N, I am about to find out but until then do not tow your hybrid car. 👍😊 

Here is some useful info, that man is a real treasure to the hybrid world, if there are people that haven’t seen his videos I highly recommended you to watch all of his Toyota work productions. 

Have a good day 

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Mick F Hi,If you understand how an 'Epicyclic' gear works you have your answer. The Ring gear is driven via the Planetary gears by the Sun gear and vice versa. One side either Ring or Sun drives the wheels. Therefore when the wheels turn they will turn the attached gear (say the Ring), which will then spin the Planetary gears and keep the Sun gear turning. That's also how you can charge the Battery going downhill. There's a 'You Tube' clip that explains it , albeit on an Auris, but the Yaris is the same idea.

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Yes, Bomber, I understand how planetary and sun gears work.

No issue with stuff turning when the wheels go round.  I understand.  What I don't understand is why the car is free to move in N ........ when it doesn't charge the Battery, and everything is switched off, and the gearbox is oiled.  It can only be as Tony has said above, that the MGs won't be cooled as the coolant is electrically driven.

Will the MGs get hot if doing no work?  That is another question perhaps.

Mick.

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Official statement under "precautions" in Hybrid repair manual:

  1. Precautions to be observed when towing

    1. Tow the damaged vehicle with its front and rear wheels lifted off the ground.

      CAUTION:

      Towing the damaged vehicle with its front wheels on the ground will cause the motor to generate electricity. This electricity could, depending on the nature of the damage, leak and cause a fire.

  2. Towing with the 4 wheels on the ground

    CAUTION:
    • If the vehicle needs to be towed using a rope with all 4 wheels on the ground, do not exceed 30 km/h (19 mph) and tow only for a short distance, such as distances required to load onto a lift-type truck or flatbed truck.

    • Turn the ignition switch to ON (IG), move the shift lever to N position.

    • Make sure not to turn the ignition switch off while the vehicle is being towed, or move the shift lever to P position, as it may result in damage or an accident.

    • If any abnormality is present in the damaged vehicle while towing, stop towing immediately.

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Towing the damaged vehicle with its front wheels on the ground will cause the motor to generate electricity.

We have a thread on here regarding where the electricity goes when the Battery is FULLY charged as when descending a LONG hill.  Someone cited a long hill in Scotland.  I know of one on the A9 where coming south to Pitlochry is 20miles down hill.  Done it on a bicycle and I freewheeled for all of the 20miles.

If the Battery is FULL, where does the electricity go?

Who mentioned the car being damaged?

Mick.

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PS:

Please understand I'm not arguing with Toyota, it's just that I haven't read anything that explains the single reason why you can't tow a hybrid.  There's a few explanations and reasons offered, but no actual solid facts IMHO.

Mick.

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To me, if the manufacturer of a vehicle recommends not to tow with all, front only, rear only wheels in contact with the ground then that is good nought for me. I wouldn’t do it. Why would you want to when the maker says don’t. Car handbooks are thick enough as it is without the manufacturer having to explain every technicality.

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1 hour ago, Mick F said:

If the battery is FULL, where does the electricity go?

It doesn't get created in this instance - regeneration stops, that is why the cars have a B mode to get retardation that compensates for no regen.

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35 minutes ago, Mike J. said:

It doesn't get created in this instance - regeneration stops, that is why the cars have a B mode to get retardation that compensates for no regen.

Exactly!

If there's no electricity generated, the MGs won't overheat.  The voltage is there of course by dint of the magnetic fields crossing a conductor, but as the circuit isn't complete, there's no current drawn.  Heat is produced from power produced. No current no power no heat.

Catlover, I agree with you of course.  I'm not arguing with Toyota as I've said.  I want to know WHY you can't tow a Toyota Hybrid.  No reason, as I'm not going to do it!  Just very curious about WHY you can't.

Same argument about towing a trailer maybe.  No real mechanical reason why you can't that I know of, just that Toyota say you can't but not WHY.

Off out cycling shortly, so I'l be off the air for a few hours! 😀

Mick.

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15 hours ago, Devon Aygo said:

Official statement under "precautions" in Hybrid repair manual

 

5 hours ago, Mick F said:

Who mentioned the car being damaged?

Devon Aygo quoted information from the Hybrid repair manual (not the owners manual) which has specific precautions to be aware of when towing a hybrid. As the quote is from the repair manual, references to towing would be for vehicles which have sustained some type of damage, and not necessarily caused by being towed - otherwise they wouldn't need to be repaired !!

No one has mentioned the OP's vehicles being damaged, but obviously the OP needs to be aware of the same precautions and potential damage which could be caused if their vehicle is towed.

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1 hour ago, Mick F said:

I want to know WHY you can't tow a Toyota Hybrid.  No reason, as I'm not going to do it!  Just very curious about WHY you can't.

It seems I was correct in my first guess (based on manual gearboxes with oil pumps), the oil pump doesn't work when towed (it needs the engine to run) so the gearbox will get damaged:

https://youtu.be/5lg6yC5_-Bs?t=2158

Which is interesting on fast, long downhill stretches as it would point to B mode being almost mandatory!

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If the oil pump needs the engine to run, how does the gearbox get lubricated in EV mode when the engine isn't running?

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1 hour ago, HughA said:

If the oil pump needs the engine to run, how does the gearbox get lubricated in EV mode when the engine isn't running?

EV mode only occurs at low power and speeds and for a short while, so the residual oil and that that splashes around is deemed to be sufficient - I guess.

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2 hours ago, Mike J. said:

It seems I was correct in my first guess (based on manual gearboxes with oil pumps), the oil pump doesn't work when towed (it needs the engine to run) so the gearbox will get damaged:

https://youtu.be/5lg6yC5_-Bs?t=2158

Which is interesting on fast, long downhill stretches as it would point to B mode being almost mandatory!

Thanks.  That makes complete sense.  My curiosity is sorted.

Yes, it begs the question about 20miles of running south down the A9 hill from Drumochter to Pitlochry a little problematical!

Mick.

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2 minutes ago, Mick F said:

Yes, it begs the question about 20miles of running south down the A9 hill from Drumochter to Pitlochry a little problematical!.

If I remember correctly, the engine will start if the speed is over around 42mph, so some protection if speeds are high and you are not using B mode.

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