On Wed, 20 Jul 2005 04:49:50 +0100, John Rumm
wrote:

Dave Plowman (News) wrote:
In article ws.net,
Doctor Drivel wrote:

The Prius has a 70hp petrol motor and a 70hp electric motor.


So with 140 hp, despite being light and with a good CD, it can only manage
0-60 in 12 seconds and 100 mph?

Think they calim 122bhp now... but its only 78 of your real bhp though -
since the engine is the only source of power ultimately. The claimed
output can only be sustained until the batteries are low on juice. An
enthusiastic drive round some B roads ought to see to that ;-)

Not sure I understand your point/obsession with horsepower. The
horsepower required to maintain the vehicle at a constant 60 mph in
still conditions will be about, say 15 hp (maybe less but not more) so
78 hp available seems adequate.

With respect to acceleration, sure that's important if you are going
to race the vehicle but what other true relevance does it have when
considering the car is for transportation? If you regard it as some
sort of macho toy then that is another matter. I suggest vehicles such
as the Prius are not intended for the 'boy racer' market.

On Wed, 20 Jul 2005 00:52:14 +0100, "Dave Plowman (News)"
wrote:

In article ws.net,
Doctor Drivel wrote:
23mpg, when most are way into the 50s mpg. And he believes them. At 10
secs to 60 it is NOT slow. Zips along, and not CVT or gears.

You can't even get that right. 12 seconds 0-60. Worse than a City Rover.
Which is a truly dreadful car.

See Drivel, yer 'Primus' (called that because it looks like a stove
when the dashboard lights up during system crash) is worse than the
worst Rover made, betcha feel good now! (Making my Rover better than
your 'car' again) ;-)

It's the slowest car for the money made. But what do you expect with less
power than a Mini Cooper had 40 years ago?

And from his own words the non gearbox 'doesn't increase or reduce
revs' but 'it reduces revs' ?

T i m

On Wed, 20 Jul 2005 04:49:50 +0100, John Rumm
wrote:

The claimed
output can only be sustained until the batteries are low on juice. An
enthusiastic drive round some B roads ought to see to that ;-)

Sooner than that John. Drivel kept saying '5 miles on batteries alone'
(0% kerbside emmisions) but he has since said (and it's been confirmed
elsewhere) more like 2 miles.

About the same distance your car would go on the starter motor ;-)

All the best ..

T i m

"Doctor Drivel" wrote:

At 10 secs to 60 it is NOT slow.

10 secs to 60 is positively glacial, "your" DB6 with three Prius CVT
gearboxes and 50 kilos of plumbing leaflets in the boot would be
quicker.

The Prius does have a CVT. Toyota say so, engineering minds infinitely
better than yours can see that, but the fact you can't comprehend that
a system of gears arranged as Toyota have implemented permits a
continuously variable ratio between the input and output SPEEDS comes
as no surprise given your previous ramblings.

Adjustable spanner and some 15mm pipe clips.


--

"Edward W. Thompson" wrote in message
...
On Wed, 20 Jul 2005 04:49:50 +0100, John Rumm
wrote:

Dave Plowman (News) wrote:
In article ws.net,
Doctor Drivel wrote:

The Prius has a 70hp petrol motor and a 70hp electric motor.


So with 140 hp, despite being light and with a good CD, it can only
manage
0-60 in 12 seconds and 100 mph?

Think they calim 122bhp now... but its only 78 of your real bhp though -
since the engine is the only source of power ultimately. The claimed
output can only be sustained until the batteries are low on juice. An
enthusiastic drive round some B roads ought to see to that ;-)

Not sure I understand your point/obsession with horsepower. The
horsepower required to maintain the vehicle at a constant 60 mph in
still conditions will be about, say 15 hp (maybe less but not more) so
78 hp available seems adequate.

With respect to acceleration, sure that's important if you are going
to race the vehicle but what other true relevance does it have when
considering the car is for transportation?

0-60 in 10 secs is not slow. The 0-30 time, I don't know what it is,
appears very fast. The last time I did a 0-60 start was when I was about
19, so not applicable. 100mph top speed. The limit is 70mph. It pulls 4
people very well.

If you regard it as some
sort of macho toy then that is another matter.
I suggest vehicles such as the Prius are
not intended for the 'boy racer' market.

Yep. They are to match other vehicles in performance of the same
size/class. They do that very well, and great fun to drive, smooth, eerily
quiet at times, no bumps as auto tranny change gear or no auto struggling to
get the right ratio and hunting between gears, no whining , and slipping of
CVTs. They are worth buying because the absence of a gearbox/CVT alone.

Put a Stirling engine in place of the internal combustion engine and this
thing will be super quiet and give amazing mpg. Add the large battery sets
(batteries will drop in price a manufacturing ramps up), and this thing will
amazing compared the current offerings.

It is laughable when people start comparing high mpg diesels to the Prius.
Compare a diesel of the same size and class and there is no contest
whatsoever on any point. There is a hell of a lot of ignorance towards the
Prius as this groups has clearly demonstrated.

"raden" wrote in message
...
In message ws.net,
Doctor Drivel writes

"Dave Plowman (News)" wrote in message
...
In article ws.net,
Doctor Drivel wrote:
The Community did action against Maxie because of his constant
swearing.

How about **** off dIMM, you total retard

Maxie!!!

..Maxie's had nice good swear

[snip waste of electrons]

Maxie, this man is trying to overtake you as the NGs chief swearer. Some
people have no class at all.

Do I care ?

Maxie, you do care, you do care. You like to be top dog.

"raden" mused and wrote in message
...
In message , "Dave Plowman (News)"
stupidly writes
In article ws.net,
Doctor Drivel brilliantly wrote:

The Prius has a 70hp petrol motor and a 70hp electric motor.

So with 140 hp, despite being light and with a good CD, it can only
manage
0-60 in 12 seconds and 100 mph?

Have you booked those night school classes in physics yet?

Too much knowledge is a dangerous thing

Maxie, if they don't know what to do with knowledge then maybe you are
right.

"Dave Plowman (News)" babbled in message
...
In article ws.net,
Doctor Drivel brilliantly wrote:

They need the CVT when in petrol mode because of the 'unusual' torque
characteristics of the engine.

You really haven't a clue. Petrol mode?
The electric motor is Always
turning.

Of course it is.

More garbage. I wonder if he has a minder who hold his arm when they let
him out.

snip babble

"Dave Plowman (News)" dribbled down his shirt and
wrote in message ...
In article ws.net,
Doctor Drivel superbly wrote:

23mpg, when most are way into the 50s mpg. And he believes them. At 10
secs to 60 it is NOT slow. Zips along, and not CVT or gears.

You can't even

You can.

snip disjointed babble

"Dave Plowman (News)" wrote illogical drivel in
message ...
In article ws.net,

Doctor Drivel superbly wrote:
The Prius has a 70hp petrol motor and a 70hp electric motor.

So with 140 hp, despite being

He really doesn't know. Sad but true.

snip illogical drivel

"Dave Plowman (News)" wrote in message
...
In article ,
Andy Hall wrote:
The ECVT allows the engine and motors to operate at their most
efficient points regardless of the vehicle's speed. This provides
higher fuel economy and a very smooth acceleration experience, as
there is no "shift shock" associated with conventional transmissions.
Further, the transmission requires no hydraulics or clutches (reducing
maintenance requirements), and is such a vital component to Hybrid
Synergy Drive's amazing performance that it is often referred to by
its new name: Power Split Device.

snip drivel ans complete lack of comprehension

They're clever things. But Toyota didn't invent them or
this application.

Toyota did invent it for this application. They hold the patents and
receive licence fees from other makers.

"Dave Plowman (News)" wrote in message
...
In article ws.net,
Doctor Drivel wrote:

The only thing that is Continually Variable is the ratio of the two
power
inputs, The management system decides what level of electric to petrol
motor power to combine to output to the wheels.

Explain how it varies the relative powers of engine and motor to the
wheels while maintaining a constant ratio between each and all of them.

By a management system, anything further It is a waste of time explaining it
to you as you are not very bright at all. You have been told to look at the
graphic.

On Wed, 20 Jul 2005 06:23:18 +0000 (UTC), Edward W. Thompson
wrote:

snip
With respect to acceleration, sure that's important if you are going
to race the vehicle but what other true relevance does it have when
considering the car is for transportation?

Indeed, as-long-as it can hold it's own with a typical vehicle found
on the road today (and I believe it can), otherwise it becomes an
'obstruction' (strings of vehicles having to overtake using more fuel
/ taking more risks)?

My old 2L Sierra was never an issue anywhere whereas my 1.9 non turbo
Rover is ok on it's own but can run out of puff over a certian
gradient when towing our (smallish / 350kg) folding van. I still
prefer to drop down a gear and stick in the kerb (letting folk
overtake easily if they want) than buy a bigger (less economical)
vehicle for one or two hills maybe once or twice a year?

If you regard it as some
sort of macho toy then that is another matter.

As we know some do. ;-(

I suggest vehicles such
as the Prius are not intended for the 'boy racer' market.

Like (luckily) the *majority* of vehicles seen on the road today? It's
funny today, often the difference between what yer granny might drive
and 'one of the lads' is just 10,000W of ICE and some neon lights ;-)

Eco interest has always been complicated though hasn't it. Yer
stereotypical 'Green peace / Save the whale' person may be seen on a
cycle (good) or in a 70 mpg but 'dirty' 2CV. But are poor emmissions
*actually* any worse for the planet (ignoring the smog for a second)
than very low mpg, from something that took 5 x the energy to make
than the 2CV, but may burn fuel cleaner (I'm also thinking rapid
consumption of a dwindling fuel here)? shrug

All the best ..

T i m

"T i m" stupidly wrote in message
...
On Wed, 20 Jul 2005 00:52:14 +0100, "Dave Plowman (News)"
dribbled on his shirt and then wrote:

In article ws.net,
Doctor Drivel brilliantly wrote:
23mpg, when most are way into the 50s mpg. And he believes them. At
10
secs to 60 it is NOT slow. Zips along, and not CVT or gears.

You can't even get that right. 12 seconds 0-60. Worse than a City Rover.
Which is a truly dreadful car.

See Drivel,

This one has been taking Richard Cranium pills. Another one. tsk, tsk,

snip garbage

"T i m" wrote in message
...
On Wed, 20 Jul 2005 04:49:50 +0100, John Rumm
wrote:

The claimed
output can only be sustained until the batteries are low on juice. An
enthusiastic drive round some B roads ought to see to that ;-)

Sooner than that John. Drivel kept saying
'5 miles on batteries alone'

Never said 5, Can get 4 miles max.

About the same distance your car would go on the starter motor ;-)

at 1 mph and have to replace it afterwards. Such stupidity.

"Matt" had big thought and wrote in message
...
"Doctor Drivel" brilliantly wrote:

At 10 secs to 60 it is NOT slow.

10 secs to 60 is positively

snip drivel

"Dave Plowman (News)" wrote:

In article ws.net,
Doctor Drivel wrote:
The Prius has a 70hp petrol motor and a 70hp electric motor.

So with 140 hp, despite being light and with a good CD, it can only manage
0-60 in 12 seconds and 100 mph?

Good CD? I doubt its even got a wax disc gramophone. But it does have
a CVT (according to Toyota but what do they know)

;-)


--

"T i m" wrote in message
...

Eco interest has always been complicated though hasn't it. Yer
stereotypical 'Green peace / Save the whale' person may be seen on a
cycle (good) or in a 70 mpg but 'dirty' 2CV.

A 2CV? I haven't seen one in 15 years. What planet are you on?

"Matt" wrote in message
...

But it does have a CVT

Can you point out where this CVT is in the car? Mine doesn't have one, so I
might have been short changed or maybe it fell off.

"Doctor Drivel" wrote:

"Dave Plowman (News)" wrote in message
...
In article ws.net,
Doctor Drivel wrote:

The only thing that is Continually Variable is the ratio of the two
power
inputs, The management system decides what level of electric to petrol
motor power to combine to output to the wheels.

Explain how it varies the relative powers of engine and motor to the
wheels while maintaining a constant ratio between each and all of them.

By a management system, anything further It is a waste of time explaining it
to you as you are not very bright at all. You have been told to look at the
graphic.

Mr Clarkson had a seriously painful slipped disc and so decided to get
rid of his GT40 and replace it with a Prius. At 8am this morning the
Prius was traveling at 30 mph and then later when the traffic eased Mr
Clarkson's chauffeur put his foot down and they traveled at 60 mph.

Provide typical details of petrol engine rotational speeds, electric
"engine" rotational speeds, and road wheel rotational speeds for the
two situations detailed above.

30 mph 60 mph
Petrol Engine Speed
Electric "Engine" Speed
Road Wheel Speed


answers such as "x" "2x" "3x" etc are permitted


--

On Wed, 20 Jul 2005 00:58:47 +0100, "Doctor Drivel"
wrote:


"Andy Hall" wrote in message
news
The ECVT
......
it is often referred to by
its new name: Power Split Device.

That says it all. They have put a fancy acronym to the power splitter. The
power splitter does not, input - raise or lower ratios - output; it take
two parallel power sources and combines them into one sending the combined
power to the wheels.

The only thing that is Continually Variable is the ratio of the two power
inputs, The management system decides what level of electric to petrol
motor power to combine to output to the wheels. That is "very", "very",
different to a stepless CVT that are quite common in other conventional
cars.

It strikes me that all of this is marketing hype, and the terms Power
Split Device and ECVT etc are that.....



--

..andy

To email, substitute .nospam with .gl

"Doctor Drivel" wrote:


"T i m" wrote in message
.. .

Eco interest has always been complicated though hasn't it. Yer
stereotypical 'Green peace / Save the whale' person may be seen on a
cycle (good) or in a 70 mpg but 'dirty' 2CV.

A 2CV? I haven't seen one in 15 years. What planet are you on?

Loads of them around, some even racing round circuits. You can just
about build a brand new one from the huge amount of readily available
and relatively cheap parts.


--

In article ,
John Rumm wrote:
So with 140 hp, despite being light and with a good CD, it can only manage
0-60 in 12 seconds and 100 mph?

Think they calim 122bhp now... but its only 78 of your real bhp though -
since the engine is the only source of power ultimately. The claimed
output can only be sustained until the batteries are low on juice. An
enthusiastic drive round some B roads ought to see to that ;-)

Not even an enthusiastic drive round B roads, but just ordinary suburban
use, as Autocar found out, where it did the same MPG than a BMW 330d once
the battery range was exhausted.

It's a vehicle designed to get round one problem - that of LA and cities
like it. As a town car. Not an answer to either overall CO2 emissions, or
as a general purpose vehicle, for those who can only afford one car of
this sort of price. Hence the poor sales of only 100,000 worldwide.

--
*A closed mouth gathers no feet.

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
Edward W. Thompson wrote:
Think they calim 122bhp now... but its only 78 of your real bhp though -
since the engine is the only source of power ultimately. The claimed
output can only be sustained until the batteries are low on juice. An
enthusiastic drive round some B roads ought to see to that ;-)

Not sure I understand your point/obsession with horsepower. The
horsepower required to maintain the vehicle at a constant 60 mph in
still conditions will be about, say 15 hp (maybe less but not more) so
78 hp available seems adequate.

Then why do low powered cars not sell well in the UK? Because being able
to cruise at 60 - just - doesn't suit the majority. They want *any* car to
keep up easily on the motorway up hill and down dale regardless of whether
there's a wind, or the load it's carrying. Driving an underpowered car on
today's motorways is a very frustrating experience.

With respect to acceleration, sure that's important if you are going
to race the vehicle but what other true relevance does it have when
considering the car is for transportation? If you regard it as some
sort of macho toy then that is another matter. I suggest vehicles such
as the Prius are not intended for the 'boy racer' market.

They're not intended for this country full stop. They're made for some
cities in the US, etc. As a mainly town car.

You only have to look at the latest incarnation which is a Lexus similar
in size and shape to a Range Rover. But unlike a Range Rover, can't be
used off road, or to tow heavy loads. It produces very good fuel
consumption and performance *for that class of vehicle* but has little
relevance to this country either.

--
*If one synchronized swimmer drowns, do the rest have to drown too?

Dave Plowman London SW
To e-mail, change noise into sound.

In article ws.net,
Doctor Drivel wrote:
Yep. They are to match other vehicles in performance of the same
size/class.

But not cost.

They do that very well, and great fun to drive, smooth,
eerily quiet at times, no bumps as auto tranny change gear or no auto
struggling to get the right ratio and hunting between gears,

The last auto you drove was an ancient Mini with a clapped box?

Modern autos don't 'bump' when they change gear. Or do older decent ones.

And struggle to find the right gear? Modern ones have six or seven.

no whining , and slipping of CVTs. They are worth buying because the
absence of a gearbox/CVT alone.

You had a CVT which slipped? Why didn't you get it fixed?

--
*Geeks shall inherit the earth *

Dave Plowman London SW
To e-mail, change noise into sound.

In article ws.net,
Doctor Drivel wrote:
Put a Stirling engine in place of the internal combustion engine and this
thing will be super quiet and give amazing mpg.

Which will be why Toyota use a conventional V6 in the new Lexus with a
similar drivetrain?

--
*A clear conscience is usually the sign of a bad memory *

Dave Plowman London SW
To e-mail, change noise into sound.

In article ws.net,
Doctor Drivel wrote:
They're clever things. But Toyota didn't invent them or
this application.

Toyota did invent it for this application.

They invented, in your words, a *fixed* ratio epicyclic drive?

The Model T Ford used epicyclic gears.

Now either it's more than a fixed ratio drive, or you're wrong in saying
it's not a CVT.

Take your pick.

--
*What am I? Flypaper for freaks!?

Dave Plowman London SW
To e-mail, change noise into sound.

Matt wrote:
"Doctor Drivel" wrote:

"Dave Plowman (News)" wrote in message
...
In article
ws.net,
Doctor Drivel wrote:

The only thing that is Continually Variable is the ratio of the
two power inputs, The management system decides what level of
electric to petrol motor power to combine to output to the wheels.

Explain how it varies the relative powers of engine and motor to the
wheels while maintaining a constant ratio between each and all of
them.

By a management system, anything further It is a waste of time
explaining it to you as you are not very bright at all. You have
been told to look at the graphic.

Mr Clarkson had a seriously painful slipped disc and so decided to get
rid of his GT40 and replace it with a Prius. At 8am this morning the
Prius was traveling at 30 mph and then later when the traffic eased Mr
Clarkson's chauffeur put his foot down and they traveled at 60 mph.

Provide typical details of petrol engine rotational speeds, electric
"engine" rotational speeds, and road wheel rotational speeds for the
two situations detailed above.

30 mph 60 mph
Petrol Engine Speed
Electric "Engine" Speed
Road Wheel Speed


answers such as "x" "2x" "3x" etc are permitted

It isn't free to split speed/power any which way, it's all interlinked.

Reading from the simulation at
http://homepage.mac.com/inachan/prius/planet_e.html:

At 30mph (~50kmh):

electric 1800rpm
petrol 0-3105rpm
generator varies (with petrol engine speed) between -4680 and +6498 rpm
(+/-6500 allowed)

At 60mph (~100kph):

electric 3600rpm
petrol 1000-4405rpm
generator between -5760 and +6498rpm

As you can see, the electric motor speed is directly related to wheel speed,
the petrol engine runs variably depending how much power is required for
charging or topping up from the generator, and the generator runs at
whatever speed is needed to make the other speeds go right.

Other interesting points (from the simulation, the real car may be
different...):

At a standstill, the petrol engine can run from 0-1805rpm to get just the
generator running from 0-6500.
Max speed on just the electric motor ('stealth mode') is 69kmh, 43mph.

Not trivial to control, but well within current technology.

Hmm. Is it altering ratios? Not sure now I've looked at it more. It is
altering the split but all of the gears are fixed and constantly meshed.
What is controlled appears to be the petrol engine speed, chosen to suit the
amount of charge needed for battery and direct electric motor use, and to
keep the generator revs within limits. Also controlled is the electric motor
speed, directly affecting the road speed.

So the Power Split Device (PSD) is not really altering anything, the control
changes take place external to it.

Whether that makes it a CVT depends where you consider the 'transmission'
boundaries to be. Is it the entire system, or the system from the motor
output shafts to the driveshafts, or what?

Certainly the PSD does not do the same job as a gearbox or a 'normal' CVT as
attached to a single petrol engine.

Also, and this may be the most important point of all, does it matter? It
works, it's a step forward, it's interesting.

In article ws.net,
Doctor Drivel wrote:
Explain how it varies the relative powers of engine and motor to the
wheels while maintaining a constant ratio between each and all of them.

By a management system, anything further It is a waste of time
explaining it to you as you are not very bright at all. You have been
told to look at the graphic.

Oh, I understood how it works from day one. It's you that doesn't.

--
*What was the best thing before sliced bread? *

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
Matt wrote:
So with 140 hp, despite being light and with a good CD, it can only manage
0-60 in 12 seconds and 100 mph?

Good CD? I doubt its even got a wax disc gramophone. But it does have
a CVT (according to Toyota but what do they know)

CD. Coefficient of Drag (in air). The lower the figure, (in theory) the
better the efficiency at speed. A low powered vehicle like the Prius
desperately needs a good one to make a respectable speed. That's why it's
so ugly.

--
*The colder the X-ray table, the more of your body is required on it *

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
Matt wrote:
Mr Clarkson had a seriously painful slipped disc and so decided to get
rid of his GT40 and replace it with a Prius.

And of course that the GT 40 kept on breaking down...

At 8am this morning the
Prius was traveling at 30 mph and then later when the traffic eased Mr
Clarkson's chauffeur put his foot down and they traveled at 60 mph.

Provide typical details of petrol engine rotational speeds, electric
"engine" rotational speeds, and road wheel rotational speeds for the
two situations detailed above.

30 mph 60 mph
Petrol Engine Speed
Electric "Engine" Speed
Road Wheel Speed


answers such as "x" "2x" "3x" etc are permitted

The laugh is that anyone who's ever driven a Prius or been in one would
notice by the engine note that it behaves exactly like a CVT over a
certain speed.

Which means that Evil has never even been in one.

--
*Sleep with a photographer and watch things develop

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
PC Paul wrote:
Whether that makes it a CVT depends where you consider the
'transmission' boundaries to be. Is it the entire system, or the system
from the motor output shafts to the driveshafts, or what?

A CVT is a constantly variable transmission. Ie, no actual fixed gear
ratios within its upper and lower limits.

It conventionally means pulleys and belts, but that's only because that's
the common way. Other principles exist.

--
*If you must choose between two evils, pick the one you've never tried before

Dave Plowman London SW
To e-mail, change noise into sound.

"John Rumm" wrote in message
...
Doctor Drivel wrote:

The ratio is continously variable


.....oh no! failure. The planetary cluster is referred to as a
power-splitter. A normal gearbox/CVT lowers and raises ratios. No
ratios
are raised and lowered.

Nonsense.

"CVTs have been around for a while and at first it doesn't seem that Toyota
has broken new ground here. This, however, is entirely false, because the
ECVT in the Prius works in a completely different manner from any other CVT
put into a production car. It is so different, that calling it a CVT is
misleading. However, using this semi-familiar term at least explains why
the pitch of the engine sound doesn't rise as you accelerate."

Note: "calling it a CVT is misleading"

"The Prius transmission produces one of the effects of a CVT but not the
other. The spin rate of the engine can be selected to produce the required
power but otherwise to spin no faster than is necessary to maintain fuel
efficiency. The Prius engine tone therefore sounds as if the car has a CVT
because it does not rise as the car picks up speed. Instead, it rises and
falls with power demand, in other words, how hard you press on the
accelerator pedal."

Note: "it rises and falls with power demand", not raises and lowers ratios.

" The Prius transmission does not, however, multiply up engine torque at low
vehicle speed."

Note: No raising or lowering of ratios, as rasing and lowering torque is
what gearboxes/CVTS do.

"This is because it has only one gear ratio".

Note: so no gearbox/CVT to lower and raise ratios as there is only one.

" Effectively, the engine is coupled to the wheels as if the car is always
in top gear. This would be a crippling limitation, if not for the presence
of a powerful electric motor in addition to the gasoline engine. With this
motor adding its considerable torque, people have said that the car feels as
if it's always in bottom gear!"

http://home.earthlink.net/~graham1/M.../ContinuouslyV
ariableTransmission.htm

"Dave Plowman (News)" wrote:

In article ,
Matt wrote:
So with 140 hp, despite being light and with a good CD, it can only manage
0-60 in 12 seconds and 100 mph?

Good CD? I doubt its even got a wax disc gramophone. But it does have
a CVT (according to Toyota but what do they know)

CD. Coefficient of Drag (in air). The lower the figure, (in theory) the
better the efficiency at speed. A low powered vehicle like the Prius
desperately needs a good one to make a respectable speed. That's why it's
so ugly.

I knew that Dave hence the smiley in the original post - maybe it
needed more than one!


--

"Andy Hall" wrote in message
...
On Wed, 20 Jul 2005 00:58:47 +0100, "Doctor Drivel"
wrote:


"Andy Hall" wrote in message
news
The ECVT
......
it is often referred to by
its new name: Power Split Device.

That says it all. They have put a fancy acronym to the power splitter.
The
power splitter does not, input - raise or lower ratios - output; it
take
two parallel power sources and combines them into one sending the
combined
power to the wheels.

The only thing that is Continually Variable is the ratio of the two power
inputs, The management system decides what level of electric to petrol
motor power to combine to output to the wheels. That is "very", "very",
different to a stepless CVT that are quite common in other conventional
cars.

It strikes me that all of this is marketing hype, and the terms Power
Split Device and ECVT etc are that.....

Toyota have put an "E" in front of CVT, to differentiate it from
conventional CVTs. It is nothing like a conventional CV, is construction,
as there is none, or in function. Putting a "P", for power, in front would
have been more apt and meaningful... PCVT. The term "power splitter" is
semi-apt as that is what it does, but its prime function is to "combine"
power from two differnt souces, rather than split it. See my other post on
this.

"Matt" wrote in message
...
"Doctor Drivel" wrote:

"Dave Plowman (News)" wrote in message
...
In article ws.net,
Doctor Drivel wrote:

The only thing that is Continually Variable is the ratio of the two
power
inputs, The management system decides what level of electric to
petrol
motor power to combine to output to the wheels.

Explain how it varies the relative powers of engine and motor to the
wheels while maintaining a constant ratio between each and all of them.

By a management system, anything further It is a waste of time explaining
it
to you as you are not very bright at all. You have been told to look at
the
graphic.

Mr Clarkson

rather silly as usual.

snip nonsense about a fat, silly, no taste in clothes, boy racer on TV

"Matt" wrote in message
...
"Doctor Drivel" wrote:


"T i m" wrote in message
.. .

Eco interest has always been complicated though hasn't it. Yer
stereotypical 'Green peace / Save the whale' person may be seen on a
cycle (good) or in a 70 mpg but 'dirty' 2CV.

A 2CV? I haven't seen one in 15 years. What planet are you on?

Loads of them around,

Sure they are.

snip babble

"Dave Plowman (News)" wrote in message
...
In article ,
John Rumm wrote:
So with 140 hp, despite being light and with a good CD, it can only
manage
0-60 in 12 seconds and 100 mph?

Think they calim 122bhp now... but its only 78 of your real bhp though -
since the engine is the only source of power ultimately. The claimed
output can only be sustained until the batteries are low on juice. An
enthusiastic drive round some B roads ought to see to that ;-)

Not even an enthusiastic drive round B roads, but just ordinary suburban
use, as Autocar found out,

this half-wit still believes lies from an third rate mag. Sad but true.

snip drivel

PC Paul wrote:

Hmm. Is it altering ratios? Not sure now I've looked at it more. It is
altering the split but all of the gears are fixed and constantly meshed.
What is controlled appears to be the petrol engine speed, chosen to suit the
amount of charge needed for battery and direct electric motor use, and to
keep the generator revs within limits. Also controlled is the electric motor
speed, directly affecting the road speed.

It is the difference between the two motor speeds that gives you the
variable ratio (from the petrol engine's POV). In spite of the
constantly meshed cogs etc, you can get a variation in ratio between
petrol engine and wheels because the gear system requires the output
rotational speed of the engine to be supplied to the wheels *and* the
generator at all times, and one is traded off against the other.

It is much the same was as the way rear axle differential on a
conventional car transmission works. It allows the apparent drive ratio
between engine and one wheel vary continuously - it can only do that by
virtue the rotational speed of the other driven wheel compensating.

The prius gearbox does the same trick except the output from the "diff"
is not a wheel on one side and a wheel on the other, but the drive to
the wheels on one side, and the drive to the generator on the other.

So the Power Split Device (PSD) is not really altering anything, the control
changes take place external to it.

Whether that makes it a CVT depends where you consider the 'transmission'
boundaries to be. Is it the entire system, or the system from the motor
output shafts to the driveshafts, or what?

This is one of the mechanisms that Drivel uses to continue this
pointless discussion. No matter how many analyses are presented to him
that consider the "transmission" being the entire system that connects
motive power from the engine to the wheels, he ignores that and then
immediately imposes his own interpretation of what a "CVT" is, and
argues that the prius does not match this.

Well fair enough, it may not match his minds view of a CVT, but looking
at the big picture it is undeniably a "T" and it can "CV".

It is like a conversation that goes: "That is a tree", and some fool
repeats endlessly "I keep telling you it is not a pine tree, because the
leaves fall off each winter".

Certainly the PSD does not do the same job as a gearbox or a 'normal' CVT as
attached to a single petrol engine.

By slightly devious means it does for the petrol engine, but not the
motor (as described above).

This is also further complicated by the fact there is more than one type
of prius by the sounds of it. The first one had just the PSD, the latest
models sound like they have had a conventional CVT bolted onto the PSD's
output (presumably to deal with the crude and lumpy acceleration the
early reviewers noted on the first models).

Also, and this may be the most important point of all, does it matter? It

No not at all. Like most discussions of this type the technical factors
are to all intents irrelevant to everyone but the anoraks, and we/they
don't usually have final say in real life!

(like two programmers arguing over whether language A or B is the best
technical choice for project X. A manager then comes along and mandates
language E on the grounds that he has staff sitting there doing nothing
who can already program in it, and he spent good money on a compiler for
it only last year).

What it comes down to in my mind is a combination of:

1) and what image and desirability does the car have
2) what is it like to drive and live with
3) is the financial argument going to stack up in its favour

As any good salesman will tell you, the technical details of any buying
decision don't actually matter in cases like this because they are only
used to justify the purchase afterwards (or fantasy purchase in Drivil's
case). The overriding factor that will make you go out and lay down big
money for a new car is simply "do you want one?".

works, it's a step forward, it's interesting.

Works, yes. Step forward in terms of ongoing development certainly, but
debatable in terms of the current end result. On a practical level it
seems as if does not currently drive as well as a Turbo Diesel, and does
not do noticably better in economy. They performance is down on a TD,
and the handling uninspiring. So it is probably not going to win over
any enthusiastic drivers. In comparison to the TD it is a little cleaner
(assuming you are comparing with one that deals with the particulate
emissions).

Interesting - yup could be... right up until you find yourself cornered
in a pub by the likes of Drivel. You can imagine the sort of captivating
conversation you would get from a Mac fanatic who has just got OS/2
running on it! (with the charm of a door to door electricity/gas vendor
salesman)

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

"PC Paul" wrote in message
...


It isn't free to split speed/power any which way, it's all interlinked.

Reading from the simulation at
http://homepage.mac.com/inachan/prius/planet_e.html:

At 30mph (~50kmh):

electric 1800rpm
petrol 0-3105rpm
generator varies (with petrol engine speed) between -4680 and +6498 rpm
(+/-6500 allowed)

At 60mph (~100kph):

electric 3600rpm
petrol 1000-4405rpm
generator between -5760 and +6498rpm

As you can see, the electric motor speed
is directly related to wheel speed,

The electric motor is permanently meshed into the wheels at all times, so
not raising and lowering of ratios by gears or belts. When it decelerates
it claws back kinetic energy and puts into the battery.

the petrol engine runs variably depending
how much power is required for
charging or topping up from the generator,
and the generator runs at whatever speed
is needed to make the other speeds go right.

That's right The petrol motor comes in to assist the electric motor to give
the right amount of power/torque at the wheels.

Other interesting points (from
the simulation, the real car may be
different...):

At a standstill, the petrol engine can run from 0-1805rpm to get just the
generator running from 0-6500.
Max speed on just the electric motor ('stealth mode') is 69kmh, 43mph.

Not trivial to control, but well within current technology.

Well it works. It's not a theory.

Hmm. Is it altering ratios? Not sure now
I've looked at it more. It is altering the
split but all of the gears are fixed and
constantly meshed.

The split is primarily "combining" the powerr from the two motors.

What is controlled appears to be
the petrol engine speed, chosen to suit the
amount of charge needed for battery
and direct electric motor use, and to
keep the generator revs within limits.
Also controlled is the electric motor
speed, directly affecting the road speed.

So the Power Split Device (PSD) is
not really altering anything, the control
changes take place external to it.

By changing control you change the affect of the power split device.

Whether that makes it a CVT depends
where you consider the 'transmission'
boundaries to be. Is it the entire system,
or the system from the motor
output shafts to the driveshafts, or what?

What "Continually Varies", is the ratio of power from the two motors to
make one total power output to the wheels. No raising or lowering of
ratios, raising or lowering torque, as the lunatics here seem to think it
is. There is no gearbox/CVT, or even a reverse gear, which is great thing
in itself. A great step forward.

Certainly the PSD does not do the
same job as a gearbox or a 'normal' CVT as
attached to a single petrol engine.

Not at all. To just ouputs the total power from the motors to the wheels at
the power/torque required.

Also, and this may be the most important point of all, does it matter? It
works, it's a step forward, it's interesting.

It is brilliant, simple and well thought out. A super elegant design. The
Japanese engineers have done a brilliant job.

If you look at the power splitter. It could combine the outputs of two
small IC engines. One tuned to low end torque and one tuned to high end
torque. The two motors could be in the same block side by side, say two 3
cylinder units with two lines of cylinders. Or like a flat VW engine, with
the low engine on one bank and the high on the other. The same lubrication
system for both. The power splitter at the end of the block(s) going
directly to the wheels. Only the low torque engine has a starter motor, as
the low torque motor would start the high torque motor after revving it over
1000rpm. No CVT or power sapping auto trans, although a simple auto clutch
arrangement to disconnect the low end torque motor from the wheels would be
needed.

It could be done and far better than what we have right now, but the hybrid
has made that redundant before it is off the drawing board.

What is clear is that newly designed cars are not going be the same from now
on.