Posted by rjdriver on April 30, 2012, 4:45 pm
> On 4/30/2012 6:09 AM, Elmo P. Shagnasty wrote:
> >>> "CVT" does not by definition mean "variable width pullies and a belt".
> >>> It simply means that the transmission does not have stepped, discrete
> >>> gears.
> >> True, but the difference still needs to be pointed out as some see eCVT and
> >> assume cone and belt, not a computer controlling the speed and direction
> >> difference between 2 motor/generators attached to a planetary gearset.
> > Eh. So?
> Exactly. High-tech electro-mechanical slush for the box.
I should not have used the word "slide" to refer to what happens in
the planetary gearset used in the Prius PSD (variable transmission).
Although it occurs smooth enough (except for News) to refer to it that
way. It's actually a very interesting way to transfer power between
multiple sources, and, as everything else in the Prius, is geared
towards (no pun intened) maximum efficiency and MPG.
Fascinating interactive animation here: http://eahart.com/prius/psd/
Make my slush cherry flavored, please
Bob
Posted by News on April 30, 2012, 5:47 pm
On 4/30/2012 12:45 PM, rjdriver wrote:
>> On 4/30/2012 6:09 AM, Elmo P. Shagnasty wrote:
>>
>>
>>>>> "CVT" does not by definition mean "variable width pullies and a belt".
>>>>> It simply means that the transmission does not have stepped, discrete
>>>>> gears.
>>
>>>> True, but the difference still needs to be pointed out as some see eCVT and
>>>> assume cone and belt, not a computer controlling the speed and direction
>>>> difference between 2 motor/generators attached to a planetary gearset.
>>
>>> Eh. So?
>>
>> Exactly. High-tech electro-mechanical slush for the box.
> I should not have used the word "slide" to refer to what happens in
> the planetary gearset used in the Prius PSD (variable transmission).
> Although it occurs smooth enough (except for News) to refer to it that
> way. It's actually a very interesting way to transfer power between
> multiple sources, and, as everything else in the Prius, is geared
> towards (no pun intened) maximum efficiency and MPG.
> Fascinating interactive animation here: http://eahart.com/prius/psd/
> Make my slush cherry flavored, please
Nice animation. Too many degrees of freedom for any single flavor.
Posted by EARTHLINK EAST on May 1, 2012, 8:09 pm
"rjdriver" wrote in message
> On 4/30/2012 6:09 AM, Elmo P. Shagnasty wrote:
> >>> "CVT" does not by definition mean "variable width pullies and a belt".
> >>> It simply means that the transmission does not have stepped, discrete
> >>> gears.
> >> True, but the difference still needs to be pointed out as some see eCVT
> >> and
> >> assume cone and belt, not a computer controlling the speed and
> >> direction
> >> difference between 2 motor/generators attached to a planetary gearset.
> > Eh. So?
> Exactly. High-tech electro-mechanical slush for the box.
I should not have used the word "slide" to refer to what happens in
the planetary gearset used in the Prius PSD (variable transmission).
Although it occurs smooth enough (except for News) to refer to it that
way. It's actually a very interesting way to transfer power between
multiple sources, and, as everything else in the Prius, is geared
towards (no pun intened) maximum efficiency and MPG.
Fascinating interactive animation here: http://eahart.com/prius/psd/
Make my slush cherry flavored, please
Bob
What's wrong with saying the gas motor has high torque at high speeds and
the electric motor has high torque at low speeds. That makes acceleration
nice and smooth for us non educated mechanics. (But happy Prius owners)
Posted by Bruce Richmond on May 3, 2012, 4:38 pm
> On 4/28/2012 10:07 PM, rjdriver wrote:
> >> On 4/25/2012 6:02 AM, rjdriver wrote:
> >>>> On 4/24/2012 7:22 PM, Bruce Richmond wrote:
> >>>>>> On 4/24/2012 9:50 AM, bwilson4web wrote:
> >>>>>>> A little pricy, $3/each, I bought two, Toyota SAE papers discussing
> >>>>>>> the Prius c:
> >>>>>>> 2012-01-1017 - Development of the New THS-II Powertrain for Compact
> >>>>>>> Vehicles
> >>>>>>> 2012-01-0623 - Development of New Hybrid Transaxle for Sub-Compact-
> >>>>>>> Class
> >>>>>>> Vehicles
> >>>>>>> I don't know your technical background but I found both papers
> >>>>>>> covered
> >>>>>>> my technical questions:
> >>>>>>> o 1.5L engine with cooled exhaust gas recirculation - improves
> >>>>>>> high-
> >>>>>>> power efficiency
> >>>>>>> o 20 module battery - saves weight
> >>>>>>> o important transaxle design changes - saves weight, volume, and
> >>>>>>> reduced noise
> >>>>>>> o improved control laws - optimized for short trips
> >>>>>>> The 'Prius c' is in effect a refined version of the NHW11 (2001-03)
> >>>>>>> but 265 lbs lighter and the practicality of a hatchback. Acceleration
> >>>>>>> is not as fast as the 1.8L ZVW30 but it is still faster than
> >>>>>>> competing, compact cars.
> >>>>>>> Bob Wilson
> >>>>>> Sluggish, in my opinion.- Hide quoted text -
> >>>>>> - Show quoted text -
> >>>>> So don't buy one.
> >>>> Indeed, I fully intended to, but now won't.
> >>> It's 10.5 second 0-60 time won't win any drag races. But as cars in
> >>> general
> >>> go, it's got plenty of company at that rate, and as small compacts go,
> >>> unassisted by super or turbo chargers, it's better than some. Hope you
> >>> test
> >>> drove it without ECO mode on. That dampens the pedal response.
> >>> And as I mentioned previously, the CV transmission can be decepetive. It
> >>> just doen't give you that "kicking into gear" surge feeling you get with
> >>> other tranmissions. The car *is* accelerating, and you *will* get up to
> >>> highways speeds in plenty of time on the entrance ramps, but you will not
> >>> have that same feeling your looking for. A turbocharged Golf TDI might
> >>> be
> >>> more suitable for you. You'll still get 50 mpg, but with the turbo and a
> >>> normal transmission, at will do 0-60 in about 8 seconds. I had my
> >>> choices
> >>> narrowed down to that and the C, but found the Golf lacking in some
> >>> critical
> >>> areas.
> >> The CVT hunted incessantly and evidenced significant hysteresis.
> >> The typical automatic slushbox has more positive feedback.
> > CVTs don't hunt. At least not in a way you should notice. If they
> > do, then something is wrong. They slide. And any hunting due to road
> > conditions and driver input should not be be perceptible. And a CVT will
> > never give you the kind of feedback you are used to, at least not with an
> > engine this small. I have driven my C for three weeks now, and there is no
> > hunting. As for your other complaint, if you did your test drive with ECO
> > mode on (salesman should have known better), that would require much more
> > pedal travel to get a response then if it was off. That kind of delay or
> > lag could easily be defined as hysteresis.
> > If you found anything to like in this vehicle at all, then I would go
> > back and drive it again. This time, tell the salesman you need to expience
> > it as it will be in real life, with just your weight in the vehicle, and no
> > passenger. Then, make sure ECO mode is off, and give it a real work out. I
> > did an informal 0-60 test today and counted it at 9 seconds. This may not
> > be the car for you, but somehow, I don't think you have seen it's full
> > potential yet.
> > Bob
> Just want to point out the the Prius does NOT have a ContinuousVT. It
> has an ECVT and ElectronicallyControlledVT (note the difference in what
> the "C" stand for). It does not have a set of sliding gears, but the
> computer controls (among other things) the ratio of the engine output
> which goes to the drive-train or to the motor-generator. With the
> motors either adding power to the wheels or sending power to the battery
> (or both), it's obviously more complicated than that, but the bottom
> line is that the Prius does not switch gears in the conventional or CVT
> sense and therefore can never "hunt".
> --
> Peace,
> bobJ- Hide quoted text -
> - Show quoted text -
On a CVT the CV part doesn't have gears since gear ratios give
definite steps. There is usually a set of pullies where one has
variable width allowing the "belt" to move in or out to change the
ratio. On some the "belt" is a stack of metal plates on a steel band
and it works in compression rather than tension. The ratio can be
controlled mechanically or by computer.
On an eCVT the computer balances forces between the electric motors,
the ICE and the output. The computer interperts the desires of the
driver based on the input at the gas peddal. If that input is spastic
the engine could hunt do to the constantly changing requests. Since
we aren't seeing the same complaint from others I would chalk it up to
operator error.
Posted by News on May 3, 2012, 5:00 pm
On 5/3/2012 12:38 PM, Bruce Richmond wrote:
>> On 4/28/2012 10:07 PM, rjdriver wrote:
>>
>>
>>
>>>> On 4/25/2012 6:02 AM, rjdriver wrote:
>>>>>> On 4/24/2012 7:22 PM, Bruce Richmond wrote:
>>>>>>>> On 4/24/2012 9:50 AM, bwilson4web wrote:
>>
>>>>>>>>> A little pricy, $3/each, I bought two, Toyota SAE papers discussing
>>>>>>>>> the Prius c:
>>
>>>>>>>>> 2012-01-1017 - Development of the New THS-II Powertrain for Compact
>>>>>>>>> Vehicles
>>>>>>>>> 2012-01-0623 - Development of New Hybrid Transaxle for Sub-Compact-
>>>>>>>>> Class
>>>>>>>>> Vehicles
>>
>>>>>>>>> I don't know your technical background but I found both papers
>>>>>>>>> covered
>>>>>>>>> my technical questions:
>>
>>>>>>>>> o 1.5L engine with cooled exhaust gas recirculation - improves
>>>>>>>>> high-
>>>>>>>>> power efficiency
>>>>>>>>> o 20 module battery - saves weight
>>>>>>>>> o important transaxle design changes - saves weight, volume, and
>>>>>>>>> reduced noise
>>>>>>>>> o improved control laws - optimized for short trips
>>
>>>>>>>>> The 'Prius c' is in effect a refined version of the NHW11 (2001-03)
>>>>>>>>> but 265 lbs lighter and the practicality of a hatchback. Acceleration
>>>>>>>>> is not as fast as the 1.8L ZVW30 but it is still faster than
>>>>>>>>> competing, compact cars.
>>
>>>>>>>>> Bob Wilson
>>
>>>>>>>> Sluggish, in my opinion.- Hide quoted text -
>>
>>>>>>>> - Show quoted text -
>>
>>>>>>> So don't buy one.
>>
>>>>>> Indeed, I fully intended to, but now won't.
>>
>>>>> It's 10.5 second 0-60 time won't win any drag races. But as cars in
>>>>> general
>>>>> go, it's got plenty of company at that rate, and as small compacts go,
>>>>> unassisted by super or turbo chargers, it's better than some. Hope you
>>>>> test
>>>>> drove it without ECO mode on. That dampens the pedal response.
>>
>>>>> And as I mentioned previously, the CV transmission can be decepetive. It
>>>>> just doen't give you that "kicking into gear" surge feeling you get with
>>>>> other tranmissions. The car *is* accelerating, and you *will* get up to
>>>>> highways speeds in plenty of time on the entrance ramps, but you will not
>>>>> have that same feeling your looking for. A turbocharged Golf TDI might
>>>>> be
>>>>> more suitable for you. You'll still get 50 mpg, but with the turbo and a
>>>>> normal transmission, at will do 0-60 in about 8 seconds. I had my
>>>>> choices
>>>>> narrowed down to that and the C, but found the Golf lacking in some
>>>>> critical
>>>>> areas.
>>
>>>> The CVT hunted incessantly and evidenced significant hysteresis.
>>
>>>> The typical automatic slushbox has more positive feedback.
>>
>>> CVTs don't hunt. At least not in a way you should notice. If they
>>> do, then something is wrong. They slide. And any hunting due to road
>>> conditions and driver input should not be be perceptible. And a CVT will
>>> never give you the kind of feedback you are used to, at least not with an
>>> engine this small. I have driven my C for three weeks now, and there is no
>>> hunting. As for your other complaint, if you did your test drive with ECO
>>> mode on (salesman should have known better), that would require much more
>>> pedal travel to get a response then if it was off. That kind of delay or
>>> lag could easily be defined as hysteresis.
>>
>>> If you found anything to like in this vehicle at all, then I would go
>>> back and drive it again. This time, tell the salesman you need to expience
>>> it as it will be in real life, with just your weight in the vehicle, and no
>>> passenger. Then, make sure ECO mode is off, and give it a real work out. I
>>> did an informal 0-60 test today and counted it at 9 seconds. This may not
>>> be the car for you, but somehow, I don't think you have seen it's full
>>> potential yet.
>>
>>> Bob
>>
>> Just want to point out the the Prius does NOT have a ContinuousVT. It
>> has an ECVT and ElectronicallyControlledVT (note the difference in what
>> the "C" stand for). It does not have a set of sliding gears, but the
>> computer controls (among other things) the ratio of the engine output
>> which goes to the drive-train or to the motor-generator. With the
>> motors either adding power to the wheels or sending power to the battery
>> (or both), it's obviously more complicated than that, but the bottom
>> line is that the Prius does not switch gears in the conventional or CVT
>> sense and therefore can never "hunt".
>> --
>> Peace,
>> bobJ- Hide quoted text -
>>
>> - Show quoted text -
> On a CVT the CV part doesn't have gears since gear ratios give
> definite steps. There is usually a set of pullies where one has
> variable width allowing the "belt" to move in or out to change the
> ratio. On some the "belt" is a stack of metal plates on a steel band
> and it works in compression rather than tension. The ratio can be
> controlled mechanically or by computer.
> On an eCVT the computer balances forces between the electric motors,
> the ICE and the output. The computer interperts the desires of the
> driver based on the input at the gas peddal. If that input is spastic
> the engine could hunt do to the constantly changing requests. Since
> we aren't seeing the same complaint from others I would chalk it up to
> operator error.
More likely folks enamored of shiny objects who overlook, or who don't
know or care enough to notice, the deficiencies.
XML site map
> >>> "CVT" does not by definition mean "variable width pullies and a belt".
> >>> It simply means that the transmission does not have stepped, discrete
> >>> gears.
> >> True, but the difference still needs to be pointed out as some see eCVT and
> >> assume cone and belt, not a computer controlling the speed and direction
> >> difference between 2 motor/generators attached to a planetary gearset.
> > Eh. So?
> Exactly. High-tech electro-mechanical slush for the box.