Auto Hold

[Cyker]

10 hours ago, ernieb said:

Yes, that’s exactly how I use mine.  Also if you are in a queue that takes awhile the MID display will flash up a warning ‘do you want auto hold if so press the foot brake’ or something like that. 
You do need to give the brake a firm press just feathering the brake will not engage the auto hold so I find I can usually use either option of the as situation demands.

That's interesting - If my Mk4 is on brake hold for too long it just disengages itself!  

I had that while stuck in the World's Biggest Carpark (i.e. the M25) for a few hours, thanks to yes - Smart Motorways! - requiring a total closure of the road because someone had broken down.

The whole car just bing'ed at me then suddenly lurched forward - It basically flashed up a message then engaged the EPB and disengaged the brake hold!

And as you may know the car will try to creep against the EPB when in D mode, which was what caused the car to lurch like that. I quickly put it into P (Which, to be fair, I should have done when I realized we weren't going to be moving any time soon...)

 

[Lawnmowerman]

55 minutes ago, Cyker said:

The only 'automatics' I have tried which had that instant response are EVs and HSDs, but you can argue they're not really automatics since they don't technically have gearboxes with multiple gear ratios and are engaged permanently!  

The HSD 'CVT' transmissions have gears - a Sun and planetary gears. 🙂

[Cyker]

Yeah but just because something has gears doesn't make it a gearbox - The differential has gears but I don't think it would be considered a gearbox!

I've heard this a lot as people think the planetary gearset in the HSD gives it gears the same way it does in a torque converter autobox, but nothing could be further from the truth.

Yes, they both use the same planetary/epicyclic gearset, but it is used in a completely different way so they can't be compared.

In an TC autobox, the planetary gearset provides distinct gear ratios (Usually 4) which you get from locking one of the individual parts (sun/carrier/ring/etc) to make the others turn at a different rate.

In the HSD, it does none of these things - Toyota have instead used it as a clever 3-way differential to 'blend' the drive inputs from MG2 and the ICE, using MG1 to arbitrate how they interact. It's really very clever and elegant, and is the only drivetrain I know of that doesn't rely on some sort of friction to transmit power - Everything is constantly engaged and there are no wearing surfaces that need to slide or clamp together.

 

[Lawnmowerman]

3 minutes ago, Cyker said:

Yeah but just because something has gears doesn't make it a gearbox - The differential has gears but I don't think it would be considered a gearbox!

I've heard this a lot as people think the planetary gearset in the HSD gives it gears the same way it does in a torque converter autobox, but nothing could be further from the truth.

Yes, they both use the same planetary/epicyclic gearset, but it is used in a completely different way so they can't be compared.

In an TC autobox, the planetary gearset provides distinct gear ratios (Usually 4) which you get from locking one of the individual parts (sun/carrier/ring/etc) to make the others turn at a different rate.

In the HSD, it does none of these things - Toyota have instead used it as a clever 3-way differential to 'blend' the drive inputs from MG2 and the ICE, using MG1 to arbitrate how they interact. It's really very clever and elegant, and is the only drivetrain I know of that doesn't rely on some sort of friction to transmit power - Everything is constantly engaged and there are no wearing surfaces that need to slide or clamp together.

 

Quite correct 👍. A box with gears then.............🙂

[Roger_N]

12 hours ago, Cyker said:

Well that's just semantics - If you can't get a manual licence in it, its an automatic. What would you consider a full automatic? By your definition, double-clutch transmissions are also automated manuals and wouldn't count, so that leaves what, CVT and torque converters? Both are also slow off the line.

But I stand by what I said - I've driven all 4 of those (single and DCT, cvt and torque conv) automatic and none of them can do a full-throttle launch with the same instant immediacy as a skillfully driven manual. If they did, they wouldn't need launch control! And launch control can't be held ready for long periods, whereas I could wait ready at a roundabout as long as I need. It's one of the reasons I've always avoided autoboxes in the past.

The only one I haven't tried is the weird Toyota CVT with the 'real' first gear - Supposedly that has a good launch, but I think it is still connected via a locking torque converter so not sure how it would work in real life.

The only 'automatics' I have tried which had that instant response are EVs and HSDs, but you can argue they're not really automatics since they don't technically have gearboxes with multiple gear ratios and are engaged permanently!  

I agree with a lot of your comments, DCT are the best for a quick pick up in auto boxes (and this may have changed) they tend not to use them in diesels rightly or wrongly  I put this down to low down torque and that possibly causing damage to the transmission etc.

The thing is a manual gear box requires skill to balance the best possible get away and just spinning your wheels, mush more skill required in the wet and there are far too many drivers that don’t possess this and as for launch control that is best left off road cars, as it is only useful for boy racers.

As a rider using sport mode helps with get away in the auto boxes I’ve used.