Hybrid cars

And the slipping of the clutch during a shift does the same on manual
transmissions. Plus modern transmissions keep the TC locked solid most
of the time, except during breakaway and during actual gear changes. Go
read some window stickers- automatics generally beat manuals (where
manuals are still even offered). Frankly, the whole idea of a dry plate
clutch is pretty neanderthal and its hard to believe manufcaturers still
use the things.

Not entirely true, but to a large degree. Back in carburetor days, a
driver with a smooth and steady foot on the gas pedal (automatic OR
standard trans) could get vastly better mileage than one with a twitchy
foot. Today, people can give their passngers a sore neck from all the
speed variations, and the computer doesn't waste an accelerator pump
shot of fuel every time the pedal moves. They still get slightly worse
mileage than good drivers, but not by the margin that used to exist.

 

The clutch doesn't slip much if you know how to drive. And, at least on my
car, the torque converter doesn't lockup until around 45 MPH. And the
manual transmission might be primitive, but so is the wheel, and we still
use it. Simple can be good.

 

Ronnie Dobbs wrote:

True. But how many million drivers are there in the world today? And how
many of those actually drive well???

The last car I had that did that was a 1983 model. My wife's old 93
locks up in partially in 2nd gear, fully in both 3rd and 4th. Its a
fairly complex algorithm, and the newer cars even moreso. The cars with
"throttle by wire" where the computer can close the throttle during
shifts don't even have to unlock the convertor during the shift.

Oh, I hear you. I like mixing gears myself, and even when it comes to
automatics I prefer a 1969 3-speed Torqueflite over anything on the
market today because its un-killable and can take full-throttle upshifts
from a 400-horsepower big-block every day of its 200,000+ mile life. But
when it comes time to think about what *should* be on the market in
today's world to make cars more and more efficient and conserve
resources, well I have to put my personal tastes aside to a degree.
Things like computer-controlled highly efficient automatics and hybrid
drive systems make a lot of sense. And the manual transmission going the
way of the Dodo (at least in generic grocery-getters) makes sense too.

 

The truth is that manual transmissions get better mileage than automatics, in most
cases. You can see for yourself on the EPA web site:

http://www.fueleconomy.gov/feg/FEG2006_GasolineVehicles.pdf

The difference is typically small, on the order of 1 mpg, but it is there. There are
some exceptions, but they often have a different set of gear ratios in recognition
that many people who opt for stick shifts want a sportier drive than those with
automatics. That makes direct comparison tough.

 

Can someone explain to me what this really means? I have always heard
this expression but I have never heard it explained.

 

Slippage of the clutch is negligible except from a start. Even then,
a skilled driver will have far less slippage than with an AT.

Well, I am a few years behind with my '98 Odyssey, but I can tell you
that I would much prefer it to have a dry plate clutch than the
soulless slushbox it came with.

 

Most of the world drives manual transmissions. Automatics are a North
American thing. Those who drive manuals regularly do a respectible job.

Most lockups still have a minimum speed. There are many other times
where they won't lock up on most cars, such as in first or second gear,
under heavy acceleration, climbing steep grades, when the engine cooling
water is cold, when overdrive is cut out, in "sport" settings, towing
heavy loads, etc. In all, the torque converter is not locked up for a
good proportion of time. Some also unlock whenever the brakes are
applied.

Manual transmissions are quite efficient, and of course they are less
expensive than automatics, so are popular in the rest of the world.

 

It's all about the transmission of horsepower, and is somewhat akin to
having reduction gears, like in the transmission. In low gears, the
transmission increases the torque at the expense of shaft RPM.

There is a description here, which might be a bit too complicated to
clearly understand:

http://en.wikipedia.org/wiki/Torque_Convertor

Here is another approach to describing the effect, which might also be
too obtuse to understand:

In short, horsepower is what does the work of moving a vehicle. In
simplest terms, power is the RPM multiplied by the torque at that RPM.
Therefore, if you attach a 2:1 gearbox with perfect efficiency to an
engine, the output shaft of the engine will be running at twice the
speed of the shaft out of the gearbox, but will only provide 1/2 the
torque. That preserves the basic power relationship.

When the torque converter is slipping, the engine RPM will be faster
than the torque converter output shaft. Therefore, like the case with
the manual gearbox, if the output shaft of the engine is running at
twice the RPM of the shaft out of the gearbox, and there is no
efficiency loss, then the torque has to be twice as high out of the
gearbox.

 

Anyone know what the rear axle ratio was on these. Ooops, old habit-
read that as "final drive ratio" I suspect they are different.

 

Depends a lot on how one defines "average". I can control shift points,
keeping rpms low, which increases throttle opening for better milage. On
my wife's van with auto, the transmission shifts way too late (higher
rpm) when accelerating.

 

The torque convertor has a unique feature in that the torque available
at the output shaft can actually be HIGHER than the torque at the input
shaft, in addition to the fact that its slippage allows the engine to
move up to a higher RPM where it can apply more torque to the input shaft.

A clutch (fluid-filled, wet plate, or dry plate- doesn't matter) can
only do the latter- let the engine rev up to a higher torque point, but
the input and output torque VALUES are the same.

The simplest form of torque convertor does its trick by having 3
elements instead of two. The input shaft drives an impeller, which
directs fluid to a turbine connected to the output shaft, but first the
fluid acts against a stator that is mounted on the "reaction shaft"
which is fixed. The stator can rotate one way, but not the other. The
result is that as the ratio of inputs shaft RPM to output shaft RPM
varies, the stator rotates or locks as needed to maximize the torque
multiplication factor. More complex forms exist, and of course the
locking TC is just about universal these days.

 

James Robinson wrote:

They're still *popular* in the US. I enjoy stirring the gears as much as
the next guy, but lets face it- a thread about hybrid vehicles and other
ways to reduce emissions and fuel consumption isn't going to appeal to
DRIVING ENTHUSIASTS period! But these cars are best suited to the vast
majority of drivers who aren't enthusiasts and use cars purely for
transportation. I'm all for that, because it takes so much scrutiny OFF
of the smaller percentage of cars tailored for us enthusiasts!

Many (most, actually) manufacturers have realized that by putting
complete control of both the engine AND transmission in the hands of the
computer they can easily achieve better emission profiles than with a
manual, and can more easily stay ahead of EPA emissions requirements
with a given engine technology. Real-world fuel efficiency is often
better as well, which is why many, many car lines aren't even offered
with a manual transmission any longer.

 

That's only haf the story... see my previous post. Torque convertors can
actually have more outuput torque than input torque because of the
presence of the stator and reaction shaft. That's why the torque
convertor was such a leap forward over the "fluid clutch" back circa 1950.

 

It's all about power. The torque converter is simply transferring power
from one side to the other, less the loss in the converter. The fact
that the output shaft is turning more slowly means that its torque has
to be higher to keep the torque X RPM product the same.

You get the same effect with an electric drive, with less efficiency
loss, which is why they are popular on heavy machinery.

That's where the gearbox comes in.

 

I disagree that ID is not science, and I disagree with how you have
characterized it. I think it is. The problem with ID is that its
backers don't believe in ID, they believe in creationism. And so they
turned ID into creationism every chance they got, sort of shooting
themselves in the foot.

Its been really weird to watch the fundamentalists wrestle with ID. If
ID would have made it in, the fundamentalists would have suddenly
realized that teachers taking a scientific approach would not have
involved any notions of God.

--
Thank you,



"Then said I, Wisdom [is] better than strength: nevertheless the poor
man's wisdom [is] despised, and his words are not heard." Ecclesiastes 9:16

 

I'd like to know where in the H___ there was anything made for automobiles
in this country in 1969 that lasted 200,000 miles? In my experience 75,000
to 90,000 miles was it. Maybe what you were talking about was foreign?

 

A torque converter is the hydraulic analog of a continuously variable
ratio drive, such as two pulleys and a belt, where the pulleys change
diameter. When rpms of two parts are different the torque transferred is
not 1:1, but variable, greater than 1:1.

 

As a physicist and a believer in ID, I still say it is metaphysics.
That being said, I think philosphy and metaphysics are not valued as
much in twentieth and twenty-first century as they used to be and that
is a shame.

However, this argument on created universe versus uncreated universe has
been a central part of metaphysics for over two millenia. It used to be
considered as a question in cosmogeny rather than biology, and is the
sense that I believe it. However, evolution is a fallout of ID. ID is
NOT in conflict with evolution. Evolution describes how living things
change, according to the laws of biology and physics. ID examines the
question, "how did laws of nature come about?"

 

How is it science? There is not one shred of evidence for ID. Science is
all about evidence. ID is anti-scientific.

Yeah, they shoot themselves in the foot every time they open their mouths.

--

 

Any Ford or Chrysler, in my experience. 200k is easy, and there are
plenty of documented half-million mile cars from the 60s.

My direct personal experiences:

I sold my '68 Ford at >200,000 miles, I still have my '66 Dodge at
270,000 miles (268k on the original engine), my '73 Plymouth at 430,000
miles, and my '69 Dodge at 160,000 miles- all running great. Dad sold
his '63 Valiant at about 300,000 miles on the original un-opened engine.
My grandmother had a '74 Dart that was sold running great at 180k, Mom
had a '74 Mercury that was sold running fine at 210k. Digging way back,
even Mom's 54 Chrysler was humming along at well over 150k, despite an
episode of going 15 miles without coolant until the cylinder heads were
glowing at ~120k (those old 331 Hemis were *tough*). Going newer, Dad
had an 83 Gran Fury that was sold at 205k, has a 92 Dakota that's still
hauling loads at 215k, and my wife has a 93 Vision TSi with 230,000 miles.

ROTFL!!! That would be "no."