The Drive-a-Toyota Act

There was talk of making some early hybrid SUVs (I think the early
Escape hybrid - perhaps before Volvo got involved) front wheel drive,
with a generator/motor driving the rear wheels. This eliminates the need
for the alternator, too.

A disadvantage is that you have limited AWD capability in the snow or
ice conditions (great for going up driveways - bad for using AWD down
the highway - of course, with computers controlling things, this is not
as big a problem, unless you're going up a mountain).

All you do is add bigger batteries, and you have a plug-in hybrid and
the ice/snow problem is reduced.

Jeff

 

I always thought electric motors would make AWD very simple.[/QUOTE]

They do. Someone's doing that today.

 

They do. Someone's doing that today.[/QUOTE]

Who? Just curious.

Jeff

 

One single datum point does not prove anything.

Modern fluid drive automatic transmissions, especially from the likes of
Chrysler, are junk waiting to burst into pieces at any moment.[/QUOTE]

Do you know what "Fluid Drive" is? It was used from 1939-1954. Using
the clutch to go from one range to the next, you have a foolproof
transmission. Mine does not leak, shifts perfectly, and is a tribute
to simplicity for 67 years. Not to burst your bubble on Chrysler
transmissions, but my 1970 Dart with TorqueFlite never developed one
"datum" of trouble.

 

Not to burst your bubble on Chrysler transmissions, but my father's 77
LeBaron's transmission dropped out of the car, on the freeway, at speed,
when the car was a couple years old. Chrysler denied any problems and
refused to fix it.

They were practicing for denying any responsibility for the K-car
electrical systems, particularly in the coupes (Shelby, anyone?).

Chrysler can kiss my ass.

 

Who? Just curious.[/QUOTE]

I've been trying to remember. I saw a mention of it in Car and Driver
magazine, I believe.

 

Semantic technical point here: Yes - a generator converts mechanical
energy to electrical energy. It is only initial convention (before
portable alternators became practical with the development of compact
and efficient solid-state rectification means) that originally limited
the word generator to d.c. generating devices (basically from common
usage of the word in the context of the automobile).

Later, when the portable alternator was developed (or became practical -
and almost necessary due to the increasing current demands of cars),
just to distinguish the terminology, they came up with the term
"alternator" (which -yes - does suggest a.c. from a pure language
standpoint). However, there really is no reason the term generator -
from a pure language standpoint - could not mean alternator in that it
*generates* (i.e., no reason any device that generates *anything* could
not be referred to as a "generator").

NOW - having said that - one point I was making is that many of the auto
manufacturers have, within the last 5 or 10 years (not sure of the exact
time frame - they kind of snuck it in on us), in their documentation
(service manuals, etc.) gone back to the term "generator" to mean what
they had previously been calling (and you and I still call out of habit)
"alternators". And there's nothing wrong with that. If you look at an
alternator as a black box - ignoring what's inside - it turns mechanical
energy into d.c. voltage and current. So - hey call it a generator if
you want to. (And as I pointed out - even if it's final output *were*
a.c., from a pure language perspective, there would be no reason no to
call that too a generator.)

Just wanted to get that fun point out of the way.

Now - let's go a little further (and I'm not sure how this will tie in
to the discussion of hybrid cars) - what you and I know as alternators
pushed the "generator" (meaning d.c. generator) aside in the automotive
world because it (the alternator) was inherently more capable of high
current output across a much wider useable rpm range (i.e, the
traditional d.c. generator could not supply the increasing current
demands that cars were requiring in sustained low speed and stop and go
driving unless they were geared up to spin faster at low engine rpm to
the point that they would fly apart on the upper end of the rpm scale).

And perhaps there have been some technological developments that have
overcome the previous rpm range limitations of the (d.c.) generator.
Perhaps the engine is running at a more constant rpm with the drive
train used in the hybrid? I don't know.

You may not have said that the way you intended to, but the way you
stated it, I don't buy that. There is nothing that says a (d.c.)
generator inherently has to be direct driven and that an alternator has
to be belt driven/cannot be direct driven. So unless I missed something
there, let's scratch that part of the explanation.

In reality, I would not be surprised to find out that what they use and
call a "generator" is actually more like what you and I commonly refer
to as an alternator. I would also suggest that there is a bit of
electronic processing done on the raw output of the waveform that comes
out of this spinning device as to muddy the difference between what you
and I think of as generators and alternators and their traditional
differences such that we might have trouble deciding which category in
traditional terms whatever is in the Prius really fits into. In
addition, it would blend with the manufacturers tendency to now call
alternators generators anyway.

All true - I see those points.

Got it.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

Not necessarily--but the fact that the engine isn't directly driving the
AC compressor means that the engine can shut off, or run at its peak
efficiency as needed to charge the battery. This saves bunches of gas
and keeps a huge amount of pollutants out of the air. The battery can
then dole out whatever energy it needs to whatever system demands it at
any given moment.

Shoot, every car could learn from Toyota's systems.

The beauty of Toyota's HSD (Hybrid Synergy Drive) is, in typical
Japanese fashion, at many levels. The software controlling the battery
to dole out energy means the engine can be responsible for, and tuned
for, one task: keep the battery charged. The engine doesn't have to
run as much at incredibly inefficient levels, such as when idling for
the sole purpose of running the AC or the radio or other electrical
systems.

With those electric motors there to help with low end grunt and getting
the car moving, the engine can be tuned more specifically for running at
certain efficient speeds.

True, the engine does mechanically drive things quite a bit of the time,
and always over 42mph. But it does so with varying involvement, with
the software determining how much engine output goes to the wheels and
how much goes back to the battery. That's the purpose of the Power
Split Device (PSD) and the two motor/generators: to decouple the engine
and allow varying amounts of engine power to go to various duties.

Decoupling the engine from the wheels like the PSD does is freaking
genius. Toyota got two motor/generators and power delivery out of a
very small and lightweight device, which is incredibly less complex than
a modern automatic transmission.

Also, they programmed the brakes to be by wire. That's right, the brake
pedal tells the computer what you want to do. Down to 7mph, the
generators do the braking. The result: brakes last forever. Yes, the
software has panic stops programmed for, and the car has a brake
pressure accumulator (one of the many little noises you hear) that is
always at the ready to slam the mechanical brakes for a panic stop.

http://www.cleangreencar.co.nz/page/prius-technical-info
[/QUOTE]

Good explanations.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

They do. Someone's doing that today.
[/QUOTE]

You mean like diesel locomotives? They've been AWD diesel electric for
years (but without the batteries).

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

I've been trying to remember. I saw a mention of it in Car and Driver
magazine, I believe.
[/QUOTE]

This isn't 4WD, but it does 0-60 in 4 seconds, and uses Li-ion
batteries: http://www.teslamotors.com/performance/specs.php

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

You keep mentioning Honda's failures as if that is somehow meaningful. The
rest of the industry has been buidling reliable automatic tansmissions for
decades. Perhaps you have not been around long enough to understand that.
Or perhaps you're simply enamored by Toyota's products.

 

UGH!
I and many others could tell you otherwise, but you wouldn't learn.

 

Quite correct - I and the rest of the world would not "learn" what you would
like to tell. We prefer to acknowledge what the evidence of real world fact
dictates.

 

I should clarify here that there is an almost-unmuddiable aspect of the
alternators and generators (using the terms in the traditional pre-90's
automotive sense). That is that the generator will have a commutator
(to switch current in the windings as it rotates) whereas an alternator
has slip rings (no commutation/switching of current) on the armature.
So while there are probably some uncrossable differences, some of those
still could be muddied, especially if you get jiggy with the electronics
processing of the output of whichever device is used (i.e, like
replacing the brushes and commutator with electronics, etc.)

We think of an alternator as having a field current that is teaked for
regulation. A generator could have coils instead of permanent magnets
for playing the same game. In that case, the commutation would be the
only real difference - the rectification coming from the commutator (in
a generator) up front of the actual power generation vs. in the diodes
(alternator) after the fact. See what I mean about muddying the
differences?

*BUT*, to reiterate, it still is likely that the Prius uses what we
traditionally think of as an alternator but is utilizing the retro-term
"generator" in line with the trend in the automotive world. (BTW -
since my previous post, I actually found a reference that said that the
SAE, in 1993, started officially encouraging the dropping of the
"misleading term alternator" and instead using the "proper term generator".)

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

I've been trying to remember. I saw a mention of it in Car and Driver
magazine, I believe.[/QUOTE]

It's been years since I read C&D. I would swear it was the original
Escape design.

 

http://www.ecrostech.com/prius/original/Understanding/MotorGenerators.htm



from the start page:

http://www.ecrostech.com/prius/original/InitialContents.htm

 

Well, the generator is A/C. I thought it would be D/C, but I was wrong.

http://www.hybridsynergydrive.com/en/generator.html

When the belts go around the pulley, they flex. This results in some
friction inside the belt. The pulleys are not friction free, either.
This added friction, compared with direct drive, results in some power
loss. By getting rid of the belts and pulleys, you decrease the
friction, which increases efficiency.

There is no reason why you can't have a DC generator or an A/C generator
belt driven or direct drive.

When you convert A/C to DC or vice versa, there is energy loss (as heat
in the diodes). This leads to lower efficiency. Apparently, Toyota got
over this, because the generator is A/C, not DC.

http://www.hybridsynergydrive.com/en/generator.html

 

if you want a real education on this look up the gmc truck hybrid that has been
around since 02 the engine quits when it comes to a stop and the engine restarts
when u pull away and u never know it
i drove one and didn't know till i had to work on it after the test drive and
was looking for some wiring

 

My Honda Civic and Ford Escape 4 cyl both run around 2000 RPM at 60MPH.

 

That was the original Chrysler design, reviewed in Car and Driver, for the
Dodge Durango Hybrid, called "through the road" hybrid technology.

http://www.caranddriver.com/features/3558/tech-stuff-dodge-durango-hybrid.html