Prius, Would you?
Discussion
Vladimir said:
NiMH is still very old tech in battery circles.
Still has "memory" and still discharges at a non linear rate.
Still has "memory" and still discharges at a non linear rate.
The newer Priuses are using Li-Ion. I think that the plug-in version is Li-Ion, and the 7-seat version is definitely Li-Ion.
The main advantage in this application is greater power density. In the case of the plug-in you get more electric range. In the case of the 7-seat version the battery is small enough to fit into the front armrest so you get full boot space etc.
I was talking to the Toyota service manager about this when I got mine serviced. He said that Toyota are still a little sceptical about the long-term lifespan of Li-Ion, hence most of their models (including Lexus) still use NiMH. The models using Li-Ion were chosen because they tend to be bought by early adopters who are more likely to give feedback on things like battery capacity. The Gen4 (due next year) will definitely be Li-Ion.
TheCarMadDad said:
the cvt transmission is a bit naff admittedly
No it isn't because it doesn't have a cvt transmission, it has an epicylic differential instead.
Er, yes it does. Or as Toyota would call it - ECVT
The question of "does the Prius have a CVT" comes up quite a lot.No it isn't because it doesn't have a cvt transmission, it has an epicylic differential instead.
Er, yes it does. Or as Toyota would call it - ECVT
The Prius has no conventional gearbox, whether CVT, automatic, manual or anything else. Instead, it has something called a PSD (power split device), which is the epicyclic gearset mentioned above. The planets, sun and ring correspond to the ICE output and the two motor/generators (MG1/MG2) respectively. The final drive is taken off the ring (I believe). Long story short, this enables the powertrain to do everything it needs to, with a very small number of parts.
So it doesn't have a conventional CVT, because there are no belts and no cones. The PSD could be called "continuously variable", because the final drive speed is not directly correlated to the ICE input speed, but we are really splitting hairs here.
I think the reason Toyota call it a CVT is that type approval requires them to classify the transmission, and there is no entry for "none", so they call it a CVT because it most closely mimics the character of a CVT.
AmitG said:
The question of "does the Prius have a CVT" comes up quite a lot.
The Prius has no conventional gearbox, whether CVT, automatic, manual or anything else. Instead, it has something called a PSD (power split device), which is the epicyclic gearset mentioned above. The planets, sun and ring correspond to the ICE output and the two motor/generators (MG1/MG2) respectively. The final drive is taken off the ring (I believe). Long story short, this enables the powertrain to do everything it needs to, with a very small number of parts.
So it doesn't have a conventional CVT, because there are no belts and no cones. The PSD could be called "continuously variable", because the final drive speed is not directly correlated to the ICE input speed, but we are really splitting hairs here.
I think the reason Toyota call it a CVT is that type approval requires them to classify the transmission, and there is no entry for "none", so they call it a CVT because it most closely mimics the character of a CVT.
This makes me really want one.The Prius has no conventional gearbox, whether CVT, automatic, manual or anything else. Instead, it has something called a PSD (power split device), which is the epicyclic gearset mentioned above. The planets, sun and ring correspond to the ICE output and the two motor/generators (MG1/MG2) respectively. The final drive is taken off the ring (I believe). Long story short, this enables the powertrain to do everything it needs to, with a very small number of parts.
So it doesn't have a conventional CVT, because there are no belts and no cones. The PSD could be called "continuously variable", because the final drive speed is not directly correlated to the ICE input speed, but we are really splitting hairs here.
I think the reason Toyota call it a CVT is that type approval requires them to classify the transmission, and there is no entry for "none", so they call it a CVT because it most closely mimics the character of a CVT.
So complicated, yet so simple.
AmitG said:
The question of "does the Prius have a CVT" comes up quite a lot.
The Prius has no conventional gearbox, whether CVT, automatic, manual or anything else. Instead, it has something called a PSD (power split device), which is the epicyclic gearset mentioned above. The planets, sun and ring correspond to the ICE output and the two motor/generators (MG1/MG2) respectively. The final drive is taken off the ring (I believe). Long story short, this enables the powertrain to do everything it needs to, with a very small number of parts.
So it doesn't have a conventional CVT, because there are no belts and no cones. The PSD could be called "continuously variable", because the final drive speed is not directly correlated to the ICE input speed, but we are really splitting hairs here.
I think the reason Toyota call it a CVT is that type approval requires them to classify the transmission, and there is no entry for "none", so they call it a CVT because it most closely mimics the character of a CVT.
The Prius has no conventional gearbox, whether CVT, automatic, manual or anything else. Instead, it has something called a PSD (power split device), which is the epicyclic gearset mentioned above. The planets, sun and ring correspond to the ICE output and the two motor/generators (MG1/MG2) respectively. The final drive is taken off the ring (I believe). Long story short, this enables the powertrain to do everything it needs to, with a very small number of parts.
So it doesn't have a conventional CVT, because there are no belts and no cones. The PSD could be called "continuously variable", because the final drive speed is not directly correlated to the ICE input speed, but we are really splitting hairs here.
I think the reason Toyota call it a CVT is that type approval requires them to classify the transmission, and there is no entry for "none", so they call it a CVT because it most closely mimics the character of a CVT.
great post, I always assumed it was a rubber-band type affair, but that is a far better solution.I'd argue it doesn't merely "mimic" a CVT, though - the term CVT refers to a transmission's ability to continously vary its gear ratio, no more. How that is implemented is a separate question.
paranoid airbag said:
I'd argue it doesn't merely "mimic" a CVT, though - the term CVT refers to a transmission's ability to continously vary its gear ratio, no more. How that is implemented is a separate question.
Just a question of semantics, I suppose. The term "CVT" is usually used to mean something that takes a single input shaft and produces one (or more if it has integral differentials) output shaft with a continuously variable ratio between the two. The Prius's unit takes two input shafts and varies the ratio between both of them and the road, so it's a damned slight more complex than a conventional CVT simply because it has so many more degrees of freedom.
In terms of its function, I suppose you could view it as two CVTs with a rather complicated electronically controlled differential linking them (although obviously it's not implemented like that).
Edited by kambites on Tuesday 22 April 08:27
JonnyVTEC said:
Transmission refers to transferring power? In a Prius the PSD is where the effort is actually generated so it's not really a CVT in my head on that basis.
The PSD does both jobs - it allows a variation in the ratio of motor to engine speed (which isn't part of the job of a conventional transmission) but it also controls the variation between both power sources and the wheels (which is). Lowtimer said:
"May" not "will".
One cell may discharge completely and go into polarity reversal is it's of significantly lower capacity than the others in a series-connected pack and driven into reversal by the rest continuing to provide power at significant current, i.e. when the vehicle is in use. That's not relevant in the case you were taking about: batteries being left unused for significant periods of time, when there is no current being driven through any potentially weak cell.
I believe there is also issues around electrode corrosion accelerating when batteries are highly discharged state and damaging battery (been a few years since I last investigated batteries)- NiMH tends to self discharge quite quickly, so sitting for a length can make them die I believe (having just thrown a few out that the expensive battery charger could not recover - switched to hybrid style AA)One cell may discharge completely and go into polarity reversal is it's of significantly lower capacity than the others in a series-connected pack and driven into reversal by the rest continuing to provide power at significant current, i.e. when the vehicle is in use. That's not relevant in the case you were taking about: batteries being left unused for significant periods of time, when there is no current being driven through any potentially weak cell.
All probably moot points as looks Prius are starting to come with Lithium batteries
kambites said:
To be fair, despite all the paranoia about battery memory, the Prius in all its generations remains one of the most reliable cars on the market.
And part of the reason for that is because the mechanicals have such an easy time of it due to the electric stuff helping get the car off the line. It's simply a brilliant system. stephen300o said:
Might be remembered as one of the best and most influential cars ever made.
You are not wrong. It is already the "car that saved the car" in my opinion, proving that there is still a place for private transport. You can now even buy hybrid supercars that are faster and better than anything that has gone before.AmitG said:
The question of "does the Prius have a CVT" comes up quite a lot.
The Prius has no conventional gearbox, whether CVT, automatic, manual or anything else. Instead, it has something called a PSD (power split device), which is the epicyclic gearset mentioned above. The planets, sun and ring correspond to the ICE output and the two motor/generators (MG1/MG2) respectively. The final drive is taken off the ring (I believe). Long story short, this enables the powertrain to do everything it needs to, with a very small number of parts.
So it doesn't have a conventional CVT, because there are no belts and no cones. The PSD could be called "continuously variable", because the final drive speed is not directly correlated to the ICE input speed, but we are really splitting hairs here.
I think the reason Toyota call it a CVT is that type approval requires them to classify the transmission, and there is no entry for "none", so they call it a CVT because it most closely mimics the character of a CVT.
And here is a simulator for the gearboxThe Prius has no conventional gearbox, whether CVT, automatic, manual or anything else. Instead, it has something called a PSD (power split device), which is the epicyclic gearset mentioned above. The planets, sun and ring correspond to the ICE output and the two motor/generators (MG1/MG2) respectively. The final drive is taken off the ring (I believe). Long story short, this enables the powertrain to do everything it needs to, with a very small number of parts.
So it doesn't have a conventional CVT, because there are no belts and no cones. The PSD could be called "continuously variable", because the final drive speed is not directly correlated to the ICE input speed, but we are really splitting hairs here.
I think the reason Toyota call it a CVT is that type approval requires them to classify the transmission, and there is no entry for "none", so they call it a CVT because it most closely mimics the character of a CVT.
http://eahart.com/prius/psd/
Almost as exciting as the real thing
For nerd and true petrolheads
McWigglebum4th said:
And here is a simulator for the gearbox
http://eahart.com/prius/psd/
Almost as exciting as the real thing
For nerd and true petrolheads
That is a lot of fun.http://eahart.com/prius/psd/
Almost as exciting as the real thing
For nerd and true petrolheads
Not sure if the current gen of Jazz have the same issues with Spanish, mainshaft bearings fair fairly regularly diagnosed as a whine in 1st/2nd.
Also bit of a pain to change plugs on some with 2 per cylinder and removal of the inlet manifold.
As another choice, what about the Insight? See them regularly up with low miles and FSH and another taxi drivers fav.
Someone on here bought one recently which prompted me to have a nose at the prices. 10 plate's going for £6k and up.
Ok so Im a Honda fanboi but think its a better looking car as well.
The whole £10 rfl and decent mpg gets more appealing as cameras and councils make having a spirited drive the work of the devil.
Also bit of a pain to change plugs on some with 2 per cylinder and removal of the inlet manifold.
As another choice, what about the Insight? See them regularly up with low miles and FSH and another taxi drivers fav.
Someone on here bought one recently which prompted me to have a nose at the prices. 10 plate's going for £6k and up.
Ok so Im a Honda fanboi but think its a better looking car as well.
The whole £10 rfl and decent mpg gets more appealing as cameras and councils make having a spirited drive the work of the devil.
With these feet said:
As another choice, what about the Insight? See them regularly up with low miles and FSH and another taxi drivers fav.
Someone on here bought one recently which prompted me to have a nose at the prices. 10 plate's going for £6k and up.
Ok so Im a Honda fanboi but think its a better looking car as well.
OP, In the name of all that's holy, resist this! After the brilliance that was the Mk 1 Insight, I'm afraid this one's really rather bobbins Someone on here bought one recently which prompted me to have a nose at the prices. 10 plate's going for £6k and up.
Ok so Im a Honda fanboi but think its a better looking car as well.
With these feet said:
As another choice, what about the Insight? See them regularly up with low miles and FSH and another taxi drivers fav.
Someone on here bought one recently which prompted me to have a nose at the prices. 10 plate's going for £6k and up.
Ok so Im a Honda fanboi but think its a better looking car as well.
I had a Gen2 Insight before I bought the Prius.Someone on here bought one recently which prompted me to have a nose at the prices. 10 plate's going for £6k and up.
Ok so Im a Honda fanboi but think its a better looking car as well.
On the upside, it looks better than the Prius (IMHO) and is much more fun to drive. It's actually quite entertaining to chuck around, because it's so light and you get instant torque along with a low centre of gravity (due to the streamlined shape and the location of the battery pack). It has some of that Honda driver-focussed DNA. The interior is really cool, with its crazy mix of angles and geometric shapes and the speedometer that changes colour according to the instantaneous mpg. Someone clearly had fun designing that
They are very reliable. And they are cheaper than the Prius, so you can get a newer model for the money.On the downside, it has no EV mode, so it can't run on electric power alone. It's really a petrol car with electric assistance, rather than a full hybrid. The stop-start system is a bit crazy. The CVT (conventional CVT with belts and cones) sometimes gets caught out at low speed. It's a bit cramped in the back, hence you don't see many of them being used as minicabs. NVH is not that great on the pre-2012 models. And the boot is smaller than the class average.
Fuel economy wise I got a steady 50mpg once I had got used to driving it. The air-con is powered from the engine via an accessory belt, rather than being electric like the Prius. This means that if you have the air con on the engine has to run as well, which loses efficiency.
They have a charm all of their own, and will probably run forever, but need to be bought cheap.
I think that Honda have discontinued the Insight now
They say they will bring out an all-new range of hybrids in the UK later this year or next.
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