Car Tech: Automatic, manual, double clutch, or CVT?
- 8/29/07 4:30 PM
Automatic, manual, double clutch, or CVT?
by wcunning - 8/29/07 4:30 PM
In my recent column, Tranny talk, I wrote about the why I like double clutch transmissions. What kind of transmission do you prefer, and why?
Manual all the way!
by i_am_still_wade - 8/30/07 7:00 AM In reply to: Automatic, manual, double clutch, or CVT? by wcunning
I've been driving a manual transmission so long it is second nature. The first car I ever drove was a manual. The best manual gearbox still belongs to Honda and I was actually considering the Accord Hybrid until I found it was automatic only.
I prefer manual for several reasons. 1) It usually, but not always, get better MPG. 2) I have more control over the vehicle, which means I always more alert, and 3) It prevents many people from wanting to drive my car since many people don't know how to drive a manual. No computer or machine can give you to control of a manual.
Personally, I think it is a shame that drivers' education only teaches on automatics. Everybody should be taught how to drive a manual.
kekeke
by andthepickles - 8/30/07 7:27 AM In reply to: Manual all the way! by i_am_still_wadelol tranny
Less control with manual
by mwooge - 9/6/07 7:28 AM In reply to: Manual all the way! by i_am_still_wadeI disagree with your item 2, "have more control over the vehicle". I have owned cars with manuals.
Starting from a stop on a steep hill is a pain, and even dangerous, as the car rolls backwards before the clutch engages. Hope the engine doesn't stall.
Having to manualy shift gears means taking a hand off the wheel, which is less control, usually a minor loss, unless you're in a tight situation.
stick!
by havenoname777 - 10/11/07 8:21 PM In reply to: Less control with manual by mwoogemwooge your wrong about the less control when you shift gears in a manual becuse if you drive with your left hand then you shift with your right and never take your left hand off the wheel.
-Havenoname777
have you driven a stck shift?
CVT. Hands Down.
by Mr.Wizzard - 8/30/07 8:56 AM In reply to: Automatic, manual, double clutch, or CVT? by wcunning
I live in Colombia, where about 98% of the cars have manual transmissions. I recently drove a Nissan Primera with a CVT and it's just amazing. I took it on a long hill run, and you could make all sorts of speed changes; no "gear hunting" at all. I then wanted to test acceleration on the highway and hit the gas; instead of getting a kickdown-response, the engine immediately jumped to 5,200RPMS and got pegged there, wich I later saw on the owner's manual are the RPMs which output the highest torque on the curve. Although it feels as if the car wasn’t accelerating, the speedo showed totally the opposite. There's also no slippage as with AT, so mileage is better, and the car is always ready to deliver torque. This car has a 2.0L inline 4 engine, and it can easily overtake an SUV. I recommend you read on the wikipedia or howstuffworks about CVTs, they are a wonderful yet simple concept, which I hope gets adopted by many car manufacturers...
CVT. Hands Down
by vinayababu - 9/3/07 5:05 AM In reply to: CVT. Hands Down. by Mr.WizzardThanks Wizzard, I had been a long time fan of the CVT transmission even though I have neither driver a CVT Car nor seen one but I have read a lot aboutit for the last several years,in fact I have been closely following it's development from it's original belt drive version in DAF cars to the modern steel belt drive. I am from India and eagerly waiting to drive a CVT car . I believe all future mid size cars will use this technology. It is pertinent to note that Toyota use this transmission very successfully for it's famous Prius hybrid car not to mention other production cars.
Look ma, no belts!
by albizzia - 9/5/07 8:43 PM In reply to: CVT. Hands Down by vinayababuA minor correction- the Toyota Prius uses a planetary gearset and two electric motors for their CVT. It doesn't rely on a cone and belt arrangement that can slip under heavy load, has too many parts, and wears out far too quickly.
The planetary CVT is the heart of the Hybrid Synergy Drive.
CVT. Hands Down
by vinayababu - 9/6/07 4:16 AM In reply to: Look ma, no belts! by albizziaHi albizzia
Only just seen your post.You seems to have not read my post correctly.What I have mentioned there was that the cone and belt CVT system in the original form was used in DAF Cars, may be the first production car that used such CVT about thirty to forty years ago. The CVT used in Toyota Pyrus is an improved version of this old belt drive. Instead of rubber belt drive the modern CVT uses steel strips linked steel belt. This design was perfected only in the last ten to fifteen years.
More than one type of CVT
by albizzia - 9/10/07 8:58 PM In reply to: CVT. Hands Down by vinayababuOh, I read your post correctly. I'm sorry, but you are misinformed. The steel belt and cone CVT is used on some cars, including some models of Honda Civic Hybrid, but has never been used on the Prius. The Prius and other Toyota hybrids use a planetary geared CVT system with two electric motors. For a simple explanation on how it works, see:
http://john1701a.com/prius/prius-psd.htm
http://john1701a.com/prius/presentations/prius_ths-presentation_01.htm
No cones, no steel belt. (there is a simple drive chain)
There are other types of CVT as well, including:
Toroidal drive, with input and output sides shaped like a sliced donut, wheels connect the input/output sides and tilt to vary speeds.
Hydraulic drive, which uses a hydraulic pump and hydraulic motor.
Electric drive, which uses an electric generator and motor (sometimes called "serial hybrid")
Ratchet cam drive, uses cams to convert rotary motion into reciprocating motion, and a ratchet mechanism to convert the reciprocating motion back into rotary motion.
Great Post
by Mr.Wizzard - 9/10/07 9:15 PM In reply to: More than one type of CVT by albizziaI had no idea that new transmissions where being designed based on the CVT principle. I really see the future standard for car's transmissions as some sort of CVT. I will read more on the designs you mention present on the hybrid, and I would definitively love to take a drive on a car with such specs (no priuses or the like in Colombia yet)...
Many CVT desigs
by vinayababu - 9/23/07 12:28 AM In reply to: More than one type of CVT by albizziaHi
Interesting discussions.You are right, my information was not correct, may be I was misled by the photo of the final chain drive( which looked almost like the CVT drive used in some cars).Any way thanks for the information particularly the site of 'John1701'. Let me pay tribute to that one man army who is doing a lot for popularising PHEV.
About 40 years back there was nothing but CVT tech in my head, I had even patented, and developed a new rotary hydrostatic CVT design that contained even a reverse drive mechanism.Finally it was given up after testing due to the same problem all Hyrdrostatic drives show- thermal loss and consequent loss in inefficiency.
Yes there are a number of designs in CVT, some installed in limited edition of production cars. But I still believe that the steel belted CVT system ,modern version of the original design from DAF, Denmark,is the most succcessful of all so far.Honda still use it and is popular in Europe, but it has not be came popular in US. Toyota used it for their ist model of Prius, but when they started using the power spliter dign from 2nd model onwards it was abandoned.
A few sites given below for those who would like to know further on CVT.
http://en.wikipedia.org/wiki/Continuously_variable_transmission#Ratcheting_CVT
http://auto.howstuffworks.com/cvt2.htm
www.edmunds.com/ownership/techcenter/articles/45104/article.html
http://cvt.com.sapo.pt/toc_en.htm
The power-split design ( credit for the design belong not to Toyota)I must say is an ingenious mechanism to synchanise three power drives, and the beauty is that it can also be used as a CVT, though, I believe,it is not a true CVT system as it cannot be used in any car with a ICE only.
Still self-shifting after all these years
by make_or_break - 8/30/07 11:17 AM In reply to: Automatic, manual, double clutch, or CVT? by wcunning
Now that I've finally driven one, I will admit that the DSG box that VW uses does account for itself quite nicely. But the SMG monstrosity that I tried in a M3 a year or two ago was a serious letdown.
There have been times that it would be nice not to shift (long, crappy day...gridlock...just plain worn-out), but in the end I've to answer my "restless left-foot syndrome". Can't do that with any sort of slushbox (unless you're into left-foot braking), no matter how good it thinks on its own.
Manual fan
by Rick Cavaretti - 8/30/07 12:37 PM In reply to: Automatic, manual, double clutch, or CVT? by wcunning
Can you imagine a vintage Italian sports car with a pseudo-manual? Part of the thrill is depressing the clutch pedal and rowing through the gears, blipping the throttle just right on the downshifts to get that perfect sound out of the engine. But then there's traffic. I might compromise on a modern car if I had COMPLETE control over the transmission. When I flick that paddle shifter, it shifts then and only then. If I want to hold it at redline for five minutes, so be it.
Manual
by streamline35 - 8/30/07 2:51 PM In reply to: Automatic, manual, double clutch, or CVT? by wcunning
I prefer the stick and clutch for sure. Automatics tend to be more expensive, less reliable, less fuel efficient, and a bit slower than manuals. I do admit that the CVTs are overall better than a manual (since they are more fuel efficient and faster), but a manual is so much funner.
Maybe the DSG is an improvement over the traditional automatic, and I suppose with manual shift feature it would do in a crunch, but it lacks the clutch (meaning less control and not being able to go straight to any gear). The clutch is a huge part of what makes a manual fun, and I would never take a DSG or any traditional automatic over a stick shift.
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