Originally Posted By: XS650
Originally Posted By: 440Magnum
Originally Posted By: XS650
Originally Posted By: brandini
I believe CVT's still have a torque converter.
Prius and Camry Hybrids CVTs don't have a TC. Nor do Lexus Hybrids and IIRC, nor do Ford or Altima hybrids.
Hybrids do not have a true CVT. They basically have a differential with an electric motor-generator on one shaft, the gasoline engine on the another, and the drive wheels on the third. Its not even really a "transmission" at all, which is why the manufacturers refer to it as a "drive system."
All the true CVTs do use a torque convertor, but its locked a much larger percentage of the time than in a conventional automatic.
It transmits power and is continuously changes ratios for the internal combustion engine from infinite reduction (seriously torque limited though) as he car starts to move to whatever the reduction is at cruising speed.
The common term is eCVT, electronic Continuously Variable Transmission. The function of the transmission makes it a CVT, not which combination of parts are in it.
The gearset isn't aren't a differential, the mechanical gear element is a planetary gearset (it could be done with a differential) with the engine on one input, one motor generator on another input and the 2nd motor generator hooked to the output. The 2 M/G units recirculate torque in the planetary gearset changing the ratio between the engine and output of the gearset. It's not a conventional way to do the job, but is is a continuously variable transmission.
Yes, you're right on there. There is an interesting and esoteric debate about whether the HSD transmissions are truly CVTs. Nope, they bear virtually nothing in common with the "cone and belt/chain" units more commonly seen. A logical "compromise description" might be that the Toyota/Lex design is actually a one-speed auto, in which that one speed just happens to be infinitely variable. At the end of the day, though, it functions as an exceptionally well behaved CVT. Especially in the Camry (I've driven the Prius and the Camry extensively, and had one try of a Highlander Hybrid), the behavior is superb. It's very much like a turbojet engine -- slight, non-objectionable delay in throttle response (not like the all-day delay with a turbofan), and the rpms are pretty much always right where they need to be for what you're trying to do. I just LOVE how this car responds (though I could live with another 50 hp or so -- total system hp in the Camry hybrid is 187 -- very close to the previous gen 3.0L V-6 I owned a few years back).
By comparison, I liken the wife's Avalon, with 270 hp and a 5-spd auto (the 6-spd came the next year) to a gorilla. It wins in the brute force contest, hands down, but it does all that crude, old-fashioned -- shifting. Ewwwwwwww. Once you get used to seamless power delivery, multi-speed transmissions suddenly look like a Fred Flintstone accessory.
Originally Posted By: 440Magnum
Originally Posted By: XS650
Originally Posted By: brandini
I believe CVT's still have a torque converter.
Prius and Camry Hybrids CVTs don't have a TC. Nor do Lexus Hybrids and IIRC, nor do Ford or Altima hybrids.
Hybrids do not have a true CVT. They basically have a differential with an electric motor-generator on one shaft, the gasoline engine on the another, and the drive wheels on the third. Its not even really a "transmission" at all, which is why the manufacturers refer to it as a "drive system."
All the true CVTs do use a torque convertor, but its locked a much larger percentage of the time than in a conventional automatic.
It transmits power and is continuously changes ratios for the internal combustion engine from infinite reduction (seriously torque limited though) as he car starts to move to whatever the reduction is at cruising speed.
The common term is eCVT, electronic Continuously Variable Transmission. The function of the transmission makes it a CVT, not which combination of parts are in it.
The gearset isn't aren't a differential, the mechanical gear element is a planetary gearset (it could be done with a differential) with the engine on one input, one motor generator on another input and the 2nd motor generator hooked to the output. The 2 M/G units recirculate torque in the planetary gearset changing the ratio between the engine and output of the gearset. It's not a conventional way to do the job, but is is a continuously variable transmission.
Yes, you're right on there. There is an interesting and esoteric debate about whether the HSD transmissions are truly CVTs. Nope, they bear virtually nothing in common with the "cone and belt/chain" units more commonly seen. A logical "compromise description" might be that the Toyota/Lex design is actually a one-speed auto, in which that one speed just happens to be infinitely variable. At the end of the day, though, it functions as an exceptionally well behaved CVT. Especially in the Camry (I've driven the Prius and the Camry extensively, and had one try of a Highlander Hybrid), the behavior is superb. It's very much like a turbojet engine -- slight, non-objectionable delay in throttle response (not like the all-day delay with a turbofan), and the rpms are pretty much always right where they need to be for what you're trying to do. I just LOVE how this car responds (though I could live with another 50 hp or so -- total system hp in the Camry hybrid is 187 -- very close to the previous gen 3.0L V-6 I owned a few years back).
By comparison, I liken the wife's Avalon, with 270 hp and a 5-spd auto (the 6-spd came the next year) to a gorilla. It wins in the brute force contest, hands down, but it does all that crude, old-fashioned -- shifting. Ewwwwwwww. Once you get used to seamless power delivery, multi-speed transmissions suddenly look like a Fred Flintstone accessory.
