Looking for a Torque Convertor Auto - motability car

Goudy

If depends on what version of the system the car uses.

The older system is a CVT 'box but is doesn't work the same way some other CVT 'boxes do, ie no rubber band running up and down pulleys.

The engine and/or main electric motor drives a set of planetary gears instead of the pulleys and belt. These planetary gears handle the changing output speed.

On the driven side of these gears is another electric motor/generator that handles regen and reverse.
All this is then connected to the final drive/diff by a big chain.


The latest, direct shift CVT Toyota now use is a bit different again.

The engine and/or main electric motor drives a fixed starter gear that handles the under drive, low speed part of driving the wheels, it spins up and drives the output side without power going through the variable part. One direct gear from engine/motor driving the final drive.

Once the road speed increases this direct starter gear disengages and motors drive the input pulley that drives the output pulley through a more conventional belt and pulley system similar to a scooter drive system.

So basically you have a direct drive that bypasses any gearing for slow speed and acceleration.
Then
Once it's maxed out the direct drive disengages from the output pulley and then the motors power the input pulley, that then adjusts drive via the belt to drive the output pulley and final drive.

It's meant to be smoother and quieter and the pulleys don't need to be as big or heavy as it's not having to gear all the way down for low speed, so it's also more efficient.

It reduces some of that engine speed/road speed difference as it's not always driving through the variable gearing part of the gearbox.

MouldyOldDough

Goudy said:

If depends on what version of the system the car uses.

The older system is a CVT 'box but is doesn't work the same way some other CVT 'boxes do, ie no rubber band running up and down pulleys.

The engine and/or main electric motor drives a set of planetary gears instead of the pulleys and belt. These planetary gears handle the changing output speed.

On the driven side of these gears is another electric motor/generator that handles regen and reverse.
All this is then connected to the final drive/diff by a big chain.


The latest, direct shift CVT Toyota now use is a bit different again.

The engine and/or main electric motor drives a fixed starter gear that handles the under drive, low speed part of driving the wheels, it spins up and drives the output side without power going through the variable part. One direct gear from engine/motor driving the final drive.

Once the road speed increases this direct starter gear disengages and motors drive the input pulley that drives the output pulley through a more conventional belt and pulley system similar to a scooter drive system.

So basically you have a direct drive that bypasses any gearing for slow speed and acceleration.
Then
Once it's maxed out the direct drive disengages from the output pulley and then the motors power the input pulley, that then adjusts drive via the belt to drive the output pulley and final drive.

It's meant to be smoother and quieter and the pulleys don't need to be as big or heavy as it's not having to gear all the way down for low speed, so it's also more efficient.

It reduces some of that engine speed/road speed difference as it's not always driving through the variable gearing part of the gearbox.

Thanks - but does that not mean that it feels disconnected from the wheels ?

Goudy

You are always going to get something like that as the electric motor and ICE can run independently.

The beauty of the lastet Direct Shift is very simple.
When it's likely to run in electric alone, like setting off and slower speed (which is more of the time as they have bigger batteries), it's not pushing power through the gearbox, which can be power sapping.
It's acting very much like a normal electric car, it's power is sent directly to it's final drive by one fixed gear.

When at speed and it's using the ICE or a combination of ICE and electric motor, that needs some sort of gearing to run efficiently, so it uses the gearbox, but it's a smaller, lighter and more efficient gearbox as it doesn't need the capacity to run at lower speed/gearing. All it needs it to run is the top end, higher speeds.

The older system always had to run whatever power, from whichever motor through the gears to make the wheels turn at any speed.
This is why you get that engine speed/road speed offset.
There is always a time when the engines rpm are high to drive a low gear, like pedaling a bicycle at 30 mph in it's lowest gear, your legs spin like billyo and you're red in the face!

The newer Direct system doesn't (not as much anyway) the lower gearing is handled by the fixed gear, it's only when you are up to speed does the gearbox kick in and by then the revs and road speed are better matched.

MouldyOldDough

Goudy said:

You are always going to get something like that as the electric motor and ICE can run independently.

The beauty of the lastet Direct Shift is very simple.
When it's likely to run in electric alone, like setting off and slower speed (which is more of the time as they have bigger batteries), it's not pushing power through the gearbox, which can be power sapping.
It's acting very much like a normal electric car, it's power is sent directly to it's final drive by one fixed gear.

When at speed and it's using the ICE or a combination of ICE and electric motor, that needs some sort of gearing to run efficiently, so it uses the gearbox, but it's a smaller, lighter and more efficient gearbox as it doesn't need the capacity to run at lower speed/gearing. All it needs it to run is the top end, higher speeds.

The older system always had to run whatever power, from whichever motor through the gears to make the wheels turn at any speed.
This is why you get that engine speed/road speed offset.
There is always a time when the engines rpm are high to drive a low gear, like pedaling a bicycle at 30 mph in it's lowest gear, your legs spin like billyo and you're red in the face!

The newer Direct system doesn't (not as much anyway) the lower gearing is handled by the fixed gear, it's only when you are up to speed does the gearbox kick in and by then the revs and road speed are better matched.

Thanks - I must arrange a test drive

Ditzy_Mitzy

MouldyOldDough said:

Goudy said:

If depends on what version of the system the car uses.

The older system is a CVT 'box but is doesn't work the same way some other CVT 'boxes do, ie no rubber band running up and down pulleys.

The engine and/or main electric motor drives a set of planetary gears instead of the pulleys and belt. These planetary gears handle the changing output speed.

On the driven side of these gears is another electric motor/generator that handles regen and reverse.
All this is then connected to the final drive/diff by a big chain.


The latest, direct shift CVT Toyota now use is a bit different again.

The engine and/or main electric motor drives a fixed starter gear that handles the under drive, low speed part of driving the wheels, it spins up and drives the output side without power going through the variable part. One direct gear from engine/motor driving the final drive.

Once the road speed increases this direct starter gear disengages and motors drive the input pulley that drives the output pulley through a more conventional belt and pulley system similar to a scooter drive system.

So basically you have a direct drive that bypasses any gearing for slow speed and acceleration.
Then
Once it's maxed out the direct drive disengages from the output pulley and then the motors power the input pulley, that then adjusts drive via the belt to drive the output pulley and final drive.

It's meant to be smoother and quieter and the pulleys don't need to be as big or heavy as it's not having to gear all the way down for low speed, so it's also more efficient.

It reduces some of that engine speed/road speed difference as it's not always driving through the variable gearing part of the gearbox.

Thanks - but does that not mean that it feels disconnected from the wheels ?

An automatic of any description feels 'disconnected', especially torque convertor types as they actually are!  The only gearbox that gives a positive in gear feel is a manual, in my experience.  

Goudy

I would say a dual clutch is more "connected", perhaps more so than a manual.
With a manual you have to introduce some slip yourself via the clutch, setting off and each gear change.

A dual clutch system does that for you, but it's measured in milliseconds.

Even pulling away from a standstill, my EDC gearbox only has the slightest of slip to get going, far less than I would inflict myself with a clutch pedal, then up or down changes are pretty much instant.

Floor it from the off and it will even wheel spin.

Overall, it's probably in gear, connected to the road a lot longer as it's not taking the time a manual would to change.

Ganga

Goudy said:

You are always going to get something like that as the electric motor and ICE can run independently.

The beauty of the lastet Direct Shift is very simple.
When it's likely to run in electric alone, like setting off and slower speed (which is more of the time as they have bigger batteries), it's not pushing power through the gearbox, which can be power sapping.
It's acting very much like a normal electric car, it's power is sent directly to it's final drive by one fixed gear.

When at speed and it's using the ICE or a combination of ICE and electric motor, that needs some sort of gearing to run efficiently, so it uses the gearbox, but it's a smaller, lighter and more efficient gearbox as it doesn't need the capacity to run at lower speed/gearing. All it needs it to run is the top end, higher speeds.

The older system always had to run whatever power, from whichever motor through the gears to make the wheels turn at any speed.
This is why you get that engine speed/road speed offset.
There is always a time when the engines rpm are high to drive a low gear, like pedaling a bicycle at 30 mph in it's lowest gear, your legs spin like billyo and you're red in the face!

The newer Direct system doesn't (not as much anyway) the lower gearing is handled by the fixed gear, it's only when you are up to speed does the gearbox kick in and by then the revs and road speed are better matched.

This type and i suppose all new gearboxes are going to stop the man in the street from doing their own repairs ,most mechanically minded people could change a clutch themselves but these are in a different stratosphere.

MouldyOldDough

Has anyone driven a Kia Stonic Hybrid Automatic?
Wonder what the gearbox /change is like? 

born_again

The stonic is only a Mild Hybrid. Not a proper Hybrid.
Expect up to a year for delivery. I would avoid a Mild Hybrid.

Having driven a normal petrol for 3 years. You can only just (one rear set down) get a mobility scooter in. Even a Niro is a tight fit for a mobility scooter, both the ones that come apart & the fold up ones, but at least you do not need to fold rear seat down.

Goudy

Ganga said:

Goudy said:

You are always going to get something like that as the electric motor and ICE can run independently.

The beauty of the lastet Direct Shift is very simple.
When it's likely to run in electric alone, like setting off and slower speed (which is more of the time as they have bigger batteries), it's not pushing power through the gearbox, which can be power sapping.
It's acting very much like a normal electric car, it's power is sent directly to it's final drive by one fixed gear.

When at speed and it's using the ICE or a combination of ICE and electric motor, that needs some sort of gearing to run efficiently, so it uses the gearbox, but it's a smaller, lighter and more efficient gearbox as it doesn't need the capacity to run at lower speed/gearing. All it needs it to run is the top end, higher speeds.

The older system always had to run whatever power, from whichever motor through the gears to make the wheels turn at any speed.
This is why you get that engine speed/road speed offset.
There is always a time when the engines rpm are high to drive a low gear, like pedaling a bicycle at 30 mph in it's lowest gear, your legs spin like billyo and you're red in the face!

The newer Direct system doesn't (not as much anyway) the lower gearing is handled by the fixed gear, it's only when you are up to speed does the gearbox kick in and by then the revs and road speed are better matched.

This type and i suppose all new gearboxes are going to stop the man in the street from doing their own repairs ,most mechanically minded people could change a clutch themselves but these are in a different stratosphere.

I think it's more the packaging that's the major stumbling block for jobs like these.
Front wheel drive, transverse layout cars have always been a bit fiddly to get the gearbox out.

Even before these fancy gearboxes some often required the engine and gearbox to be dropped out to get at the clutch.

I remember changing the clutch on a 1998 Rav4 4x4 and that was a nightmare even in a proper garage with a lift and all the tools. It was an engine out job.

One good thing about the Toyota CVT, they do seem to be almost indestructible.

There's plenty of the older system Toyota hybrids that hit 300,000+ miles with easy and I've read the newer direct system is perhaps even more reliable.

The OP should make a list of suitable cars with whatever auto gearboxes they have and give them a good test drive.
Take the mobility scooter with them as well, see if it fits in.