Gearbox

[Cuffley]

Hi I’ve noticed that my 450h pulls away in 4th gear? Is this normal? If I put it in sport mode it’s in 4th according to the display. I can select 1st ok and it goes into 1st. But if I switch back to D and then back again into sport it shows 4th again. I’ve have the AA come out and they can’t find any fault with their plug-in readers? But the guy did say that although they can’t pick it up, Lexus maybe able to with their equipment? Anybody else had this experience with the gearbox? 
 

Thanks 

[Herbie]

There are no separate gears, it's an eCVT (Electronic Constantly Variable Transmission) and works by way of a constantly meshed planetary gearset so you don't get the 1st, 2nd or whatever. What you're seeing are just artificial numbers.

It's a very complex but very clever system and there's no way whatsoever that I could even begin to explain how it works, so just do a search on Google or whatever for how Toyota eCVT works and you should find what you're looking for.

Here's one explanation. There's also a good animated illustration but it uses Adobe Flash and may not work anymore - but that's a bit irrelevant at the moment because I can't find it anyway

http://prius.ecrostech.com/original/Understanding/ContinuouslyVariableTransmission.htm?utm_source=LexusOwnersClubUK&utm_medium=ForumLinks

[Las Palmas]

7 minutes ago, Herbie said:

It's a very complex but very clever system and there's no way whatsoever that I could even begin to explain how it works, so just do a search on Google or whatever for how Toyota eCVT works and you should find what you're looking for.

The old DAF had a system that functioned more or less the same way. Search DAF Variomatic. Easier to understand as it is much simpler than the extremely complex CVT in Lexus.

[Cuffley]

22 minutes ago, Herbie said:

There are no separate gears, it's an eCVT (Electronic Constantly Variable Transmission) and works by way of a constantly meshed planetary gearset so you don't get the 1st, 2nd or whatever. What you're seeing are just artificial numbers.

It's a very complex but very clever system and there's no way whatsoever that I could even begin to explain how it works, so just do a search on Google or whatever for how Toyota eCVT works and you should find what you're looking for.

Here's one explanation. There's also a good animated illustration but it uses Adobe Flash and may not work anymore - but that's a bit irrelevant at the moment because I can't find it anyway

http://prius.ecrostech.com/original/Understanding/ContinuouslyVariableTransmission.htm?utm_source=LexusOwnersClubUK&utm_medium=ForumLinks

Hi Herbie. Thanks for replying. Is it faulty in my case or normal? 

[Herbie]

Just now, Cuffley said:

Hi Herbie. Thanks for replying. Is it faulty in my case or normal? 

It's normal - have a read/search for info on how they work and all shall be revealed.

[Cuffley]

Just now, Herbie said:

It's normal - have a read/search for info on how they work and all shall be revealed.

Brilliant thanks 

[Thackeray]

1 hour ago, Herbie said:

There's also a good animated illustration but it uses Adobe Flash and may not work anymore - but that's a bit irrelevant at the moment because I can't find it anyway

It's at this link but as expected the Adobe Flash bit doesn't work now after Adobe withdrew support for Flash. It's possible that some people may still have an old version of Flash on their computer and as long as they don't update it, it may still work.

It still has a good simple graphic at the top that shows the principle of the planetary gearset. Although the transmission is complex electronically and wouldn't be possible without computers, mechanically it's a very simple and elegant device with hardly anything to go wrong, compared with traditional gearboxes with several actual gearsets.

1 hour ago, Las Palmas said:

The old DAF had a system that functioned more or less the same way. Search DAF Variomatic. Easier to understand as it is much simpler than the extremely complex CVT in Lexus.

It's like the DAF system in that it produces variable ratios without actually changing the gears in use. But the DAF system used rubber bands to give varying ratios from cone shaped elements in the gearbox. Mercedes and Toyota and no doubt others use the same principle in their CVT gearboxes but the drive band is made up of steel links instead of rubber.

The Toyota/Lexus "power split device" or "eCVT" is a much more elegant concept and uses a permanently meshed planetary gearset, rather than variable ratios from the rubber/steel drive band. It's a pity that the best graphic has now disappeared from the internet but here's a presentation of an actual transmission which shows how few cogs there are compared with a traditional gearbox, manual or automatic. So it never actually changes gear - the computer just varies the speeds of the various power sources.

[Las Palmas]

Thackeray:

It's at this link but as expected the Adobe Flash bit doesn't work now after Adobe withdrew support for Flash. It's possible that some people may still have an old version of Flash on their computer and as long as they don't update it, it may still work.

 

Hi William,

The link function correct without Adobe Flash. I have the LTSC (server version) Windows from 2019 in this PC and no Adobe Flash installed. Adobe Flash was a disaster security wise. It is good is is gone. In your system there still may be parts of the Adobe Flash that are making problems. Try to install the Flash again and then get the latest uninstaller. That could make the link function.

[Thackeray]

Yes, exactly. The link still works as this is just standard http (hypertext transfer protocol). It's the Adobe Flash bit at the bottom of the page that doesn't work now. I've read that Adobe Flash animations can be converted into html5 using Adobe Animate but my computer isn't powerful enough to install this. If anyone has a copy of Adobe Animate installed, maybe they could convert the Flash animation into a file that would work properly.

[Las Palmas]

20 minutes ago, Thackeray said:

Yes, exactly. The link still works as this is just standard http (hypertext transfer protocol). It's the Adobe Flash bit at the bottom of the page that doesn't work now. I've read that Adobe Flash animations can be converted into html5 using Adobe Animate but my computer isn't powerful enough to install this. If anyone has a copy of Adobe Animate installed, maybe they could convert the Flash animation into a file that would work properly.

Do not have Adobe Animate or other flash programs and normally open only web from https and not http. Still both the links in the bottom function, so it could be some leftover programs in you computer that are having a hickup.

If you want to reinstall a previous Adobe Flash do it from the original Adobe Web:

https://helpx.adobe.com/flash-player/kb/install-previous-version-flash-player.html

They are not distributing malware.

 

[Herbie]

2 hours ago, Las Palmas said:

The link function correct without Adobe Flash

The link functions to get you to the website but there's just blank space where the Flash animation used to be:

[Las Palmas]

Thought that blank space was the place for an add and I have many blank spaces on may web sites. Ad blockers do a great job

[Greisingel]

 

[Herbie]

.

[NemesisUK]

2 hours ago, Greisingel said:

 

But Lexus e-CVT doesn't use belts..

[Greisingel]

40 minutes ago, NemesisUK said:

But Lexus e-CVT doesn't use belts..

Yes the electric motor controls the  inner rotor planetary gears. Much more robust than belt variation. No vids of ecvt. Probably too complicated. 

[Thackeray]

The CVT video above is a modern version of how the DAF CVT worked.

Here's another video about how the Toyota/Lexus eCVT works. No rubber or flexible steel bands. And bear in mind that the drive chain shown at the end of the animation doesn't exist on later models of the Prius or on the Lexus hybrid drive.

 

 

Incidentally, one of the earliest patents for this kind of system was in 1908 by John Thomas, living at The Vicarage, Holywell, Flint.

[NemesisUK]

 

[NemesisUK]

At the heart of the e-CVT

 

[Las Palmas]

In a hybrid cars, where the combustion engine provide power to the wheels of the car (and not only to the Battery like in the old Volt from GM) gearing needs to be much more complex than in a car where the wheels only get their power from electric motors. In electric motors all you need is to reverse the plus and minus to the motors to get the car going reverse.

The idea of using an engine in the car to only charge the Battery that drive the car is not too bad. Such a car could be both charged home (from those having a possibility for that) and while driving, using the engine in the car to charge the Battery, making the range larger than the cars with only Battery as fuel; an engine that is only charging a Battery can be made to run in the most economical and environmentally friendly way as it needs not speed up or slow down. Also, the engine could be made to run on various fuel types. Maybe fuel cell or oil from fast food (have read about a car smelling like pommes frites out of the exhaust pipe) or other kind of fuel when available. Electric motors are not wasting as much energy as many other motors having few moving parts.

Not only thinking of cars for private use, but busses, trucks and cargo- and cruise ships; possibly even air planes.