Hybrids - Toyota vs Honda

I wasn't talking about the Prius, I was talking about your hypothetical
vehicle which you say would have a much smaller conventional engine than
does a Prius.

John

 

Clearly not every Prius owner is a happy owner. Look here:

http://www.epinions.com/auto_Make-2002_Toyota_Prius/display_~reviews/sec_~opinion_list/pp_~2

 

But out of those 18 polled, only 1 reported a premature battery failure.

 

Right - the basic principle is to size the engine for the largest continuous
output power required. Making it smaller will cause exactly what you
describe (running out of power on long, hard uphill slopes) while making it
larger is just a waste. Making a hybrid with a 50 hp engine (as I used as an
earlier example) works just fine in the flatlands but would get a poisonous
reputation for more general use. I used 50 hp as an example for the
illustration of moving a car around in town in comparison with using a 240
hp engine. I realize in looking back that confused the issue. Sorry about
that. It is useful to note that the driver wouldn't necessarily notice the
difference in performance between a 50 hp engine and a 100 hp engine except
for the hill climbs.

Mike

 

That is the link I posted somewhere above as a tinyURL. Note the battery
failure post is awry; there is no sulfur in the hybrid battery (NaOH
electrolyte, not H2SO4). The 12V aux battery, which does have a fairly high
failure rate, is an AGM battery. It can produce sulfur dioxide, while the
hybrid battery can't.

Still, no car makes everybody happy.

Mike

 

Its true about the diesels though. Diesels sold in the US are
antiquated, lumbering beasts from the late 70s and early 80s. a modern
european diesel is not smokey, clattery, or similar. The nearest
you'll get to a euro diesel at the moemnt, is the one in the Golf, or
the one in the Dodge (actually Mercedies) Sprinter cargo van. Only
ford diesel i've been impressed with over the years, was the 1.9 they
used to have in the Ford Fiesta Cargo. The one they've put the the
s-type Jag's meant to be good though.

 

Not necessarily. It would depend at what RPMs each engine produced its
maximum torque. It is after all tongue, not HP, that get the vehicle going
from a stop and what keeps it going, at speed, up a long grade. The Pruis
uses the electric motor when staring and adds it on grades because electric
motors develop their greatest amount of tongue at start up. That is why
most Toyota are under powered, compared to many of its competitors
vehicles. . Toyota, like many import brand engines are designed to
produce their HP at higher RPMs than the engines in domestic brands, that is
why they run out of tongue rather quickly at speed.. The reason is domestics
sell mostly automatic tyrannies in the majority of their vehicles that are
equipped with tongue converters. On the other hand Japanese brands which
use the same engines in cars sold in other countries that have a much larger
percentage of their vehicle equipped with manual tyrannies. With a manual
tranny the gear selector can be used to stay on the tongue curve to climb
grades, particularly long grades. Most drivers of automatics are want to
run their cars in the lower gears to stay on the tongue curve. Follow a
Corolla equipped with a manual tranny up a long grade and it will quickly
drop off the prevailing speed, unless the drive reverts to lower gears.
Follow one with an automatic and you will see it runs out of gears trying to
maintain speed, and the speed quickly drops off, because few drivers are
willing to run their engines at the much higher RPMs in lower gears needed
to maintain the prevailing speed.

mike hunt


"Michael Pardee" . Sorry about

 

hybrids don't just work by capturing braking energy.


They run a more fuel efficient cycle with a longer expansion stroke.
The Miller/Atkinson cycle. They can do this because acceleration is
supplemented by the battery. They also have a smaller engine b/c it
can use batteries to accelerate.


By using the Miller cycle they get a higher % of energy out of the gas
and into the drivetrain.


It's very ingenious.


Hydrogen is probably never going to "be here". You need a fuel source
to get hydrogen. Hydrogen is very hard to transport (harder than
natural gas which is difficult enough) and there are no cheap "fuel
cells". The advantages of a liquid fuel are great.


I think the next step is using a smaller gas engine and a
larger/cheaper battery that you can plug in. You could plug it in for
an hour a night and that would take you maybe 30-40 miles. On longer
trips and under acceleration the gas engine would turn on. That way
you'd be replacing gas with electricity, which can come from
nuclear/coal/wind whatever.

 

In a serial hybrid (which does not yet exist in mass production) there are
no gearing issues because the engine only drives a generator, and the
electricity powers the car. We don't have the power electronics yet for
serial hybrids, but another decade should get us there.

(Getting back to the subject line...) Presently, Honda's hybrids are what
are usually called parallel hybrids. The power train is conventional except
that the engine is assisted (Honda calls it Integrated Motor Assist, or IMA)
by the electrics. Toyota uses an inventive scheme they call
"series-parallel," where a part of the engine torque is directed to the
wheels and part is used to generate electricity to power the electric motor.
That's why the Prius has no transmission per se (and can't have one), just a
skewed differential and a pair of motor/generators. They call it an
Electronic CVT. On hard uphill climbs the engine runs up to the maximum
engine speed (4500 rpm in the pre-2004s, 5000 rpm in the current ones IIRC)
and puts out full rated power with a minimum of drama, completely
independent of the car's speed. At lesser power requirements the hybrid
computer adjusts the load on the generation part to control the load on the
engine, so all aspects of the engine operation are under computer control:
mixture, ignition and valve timing, throttle and load... even whether the
engine is running or not.

Mike

 

How do you figure? You need a power source, not a fuel souce. The
power is electrical. It can be generated from wind power and solar
power. The current hydrogen research being subsidized by the Bush
administration is indeed planning on the oil industry being the
primary source of this "fuel" you mention. Otherwise they wouldn't be
subsidizing it. That's one of the main reasons hydrogen has been put
on the back burner for 30 years. Anyone with a windmill, the
production equipment, and a storage tank can produce hydrogen. No
profit there.

Hydrogen can be pressurized and stored just like propane. It is no
more dangerous than gasoline. In fact, in some ways it's safer. After
gasoline's initial explosion, the liquid gas remains and burns
furiously. Once hydrogen explodes, that's it. It's all gone. Fuel
cells are unnecessary. Hydrogen will burn in reciprocating combustion
engines just like other flammable gas (natural, propane). All this
was known 30 years ago. The boogie-man scare tactics and
disinformation are all oil industry bullshit.

nb

 

Diesels are a great fit for trucks. Hybridization just doesn't help when the
vehicle is expected to provide a lot of power for a long time, hauling loads
around. (IMA could move it off the line a little quicker, though.)

In spite of my complaint about the lack of off-the-line go power, the turbo
diesel is nearly ideal for the job. The power on the road is outstanding
(for a 10,000 GVWR truck) and the fuel economy is right at twice what the
old gasser was giving me. Not only does that translate to a money saving, it
means twice the range. No ignition to fail... I like it.

Mike

 

Proving exactly what?

Most of the battery-powered devices around my house (headlamps,
walkie-talkies, portable radios, alarm clocks, GPS receives) use the same
type of battery as in the Prius. They're about a buck each. I get them at
Target or some big-box store and recharge them until the kids accidentally
throw them out instead of swapping them out.

 

Hydrogen is less dense than propane or natural and takes alot more
energy to pressurize it (and higher pressures). Because of the higher
pressures, hydrogen tanks on a car would have to have very heavy and
thick steel.

As for burning hydrogen in a car, it would be negate the benefits of
hydrogen. The point of a fuel cell is the high efficiency. Burning it
in an engine would negate that.

You could make a case for combining hydrogen with coal to make diesel
fuel. The ease of transport alone would make it worthwhile.

A gallon of gas has about 36 kwh of heat energy. Generating that much
heat energy from wind would cost about $2.00 at a minimum. Converting
it to hydrogen at 50% efficiency would make it $4 a gallon equivalent.
And that's not counting the capital equipment to make the conversion.
Then you have the pressurization and transport losses. Oil companies
have no fear of "hydrogen". If anything they would encourage the gov't
to fund it. It's pie in the sky. What they would fear is coal to oil
technologies and conservation.

 

Wind is free. So is sunlight. Granted, at this stage these
technologies are still in their infancy, but there's a reason for
that. Hard to promote/fund a technology the developers can't
monopolize for their own gain.

This also for storage. Alloys and synthetics have replaced steel in
storage containers. Hydrogen tanker trucks ply our freeways daily
with no cavalcade of security/safety vehicles. It's all bunk. So
what if efficiency is less? Early gas engines were inefficient, too.
It's the pollution that's important.

Four decades ago a four function calculator cost $600. Today they're
in a kid's wristwatch you get free in a box of breakfast cereal. This
kind of technological advancement could have been applied to hydrogen
technology and we'd all be driving hydrogen cars today. But, there's
no incentive in exploring it and it has advanced little. You are
throwing up the same arguments the naysayers did 30 years ago. This
doesn't mean these problems are not solvable, it means no one has done
a damn thing in 30 years.

nb

 

They're not underpowered. You might try surprising us with facts for a
change. But I doubt you will.

I drove through CO, UT, AZ and NM last spring in my '01 Sienna. 5
passengers and camping equipment and it never dowhshifted on all the
freeways through the mountains (Eisenhower tunnel and Raton pass included).
Next time, I'll keep track of the Aerosaurs, Windstoppers and Freeloaders I
breeze by as they're sucking wind in the Rockies.

Actually, you'll find that the 2005 Sienna 3.3L-V6 develops its greatest
torque at a lower RPM than the Freestar's 3.9L-V6 does.* It just provides
more maximum HP at higher revs because the torque doesn't fall off as fast
at higher RPMs with the Toyota engine as it does with the Ford. I suppose
the Toyota engine is designed more carefully and machined to closer
tolerances, so it's not shaking itself to pieces at >5000rpm.

* - Source: Edmunds.com.
http://www.edmunds.com/new/2006/toyota/sienna/100604394/specs.html?
tid=edmunds.n.researchlanding.leftsidenav..8.Toyota*
http://www.edmunds.com/new/2006/ford/freestar/100542582/specs.html?
tid=edmunds.n.researchlanding.leftsidenav..8.Ford*

Oh, look, the Toyota develops more power than the bigger Freestar engine,
too:
http://www.edmunds.com/new/2006/ford/freestar/100542582/specs.html?
tid=edmunds.n.researchlanding.leftsidenav..8.Ford*

What else did Edmunds have to say about the Freestar?
http://www.edmunds.com/new/2006/ford/freestar/100542582/
researchlanding.html

"Unrefined powertrains with less horsepower and worse fuel economy than
those of competing minivans, low-grade interior materials, hard-to-remove
second-row seats..."

By the numbers...
Vehicle Curb Weight Power lb/hp MPG
Sienna 4140lbs 215 19.3 Decent
Freestar 4275lb 201 21.2 Sucky

 

Oil is also free. It is the harvesting of these things that costs money.
Wind turbines are still fairly expensive to buy and maintain, and the land
is rarely free. The electric company I work for has an 86 KW solar site on a
couple million dollars worth of land... go figure.

The storage problems may be solvable, but not yet. At a recent alternative
energy fair I saw a 3/4 ton pickup with 150 mile range, courtesy of the
three large hydrogen tanks that overfilled the bed.

I canna change the laws of physics. Hydrogen is an energy storage medium,
and as it stands is one of the least efficient of the front-runners. Methane
from hydrates is a more viable alternative to petro fuels, but its time has
not come, either.

Mike

 

Wind is free, but steel in a wind tower isn't. Generators isn't free.
The photovoltaic cells aren't close to free.

There's actually been a lot of research in wind and solar over the
years, billions of dollars worth. Countless physicists and engineers
have devoted their lives to research and development. So I don't think
it's fair to say they haven't done anything in 30 years.

The price of electricity from wind has fallen alot. I think 30 years
ago it would have been 30-40 cents per kwh, instead now its 5,
supposedly. Electronics are cheaper due to miniaturization. I don't
think the same thing is true for wind machines. They are more
efficient not and bigger but technology can only go so far.

There's alot of research in it, if it were easy to make money doing it,
it would be here.

 

They're great for cars too. Hell, the fastest 3-series BMW, is a
diesel. UK cops use diesels for their intermediate speed cars (volvo
station wagons for the high speed ones) they're comming on in leaps
ond bounds there, compaired to the US held back by its recaltrecent
truckers, and their reluctance to upgrade tractor-trailer units.

 

Certainly there are any number of alternate energy sources available
throughout the world. The problem has ALWAYS been, and continues to be,
that NONE of them in particular or even several of them in total, is
available in sufficient supply at a competitive cost to replace gasoline and
certainly not to replace the other major uses for crude oil. Except for the
one that is currently being used, more and more throughout the world as a
major source of energy with the notable exception of the US, but suggest
using more of THAT energy source drives the environuts well........nuts.
That clean, safe, low cost, unlimited and yes even renewable energy source
is nuclear power. Using nuclear power to produce electricity in countries
like Japan, China, India and several countries in Europe, is what has been
holding down an even greater increase in demand for other less
environmentally friendly fuels.

mike hunt

 

Sorry its a bit late, just catching up after a bit...

Problem is, lithiums are dangerous. When punctured, they have a
distressing tendency to, at best burn, at worst explode. Well, if you
live somewhere like the sahara, you might be ok, but moisture in the
Air + punctured cell n(such as after a crash) = BOOM. thats why. Its
well documented in RC aircraft. Oh, also their chargers are MUCH more
expensive and complex. and generally have worse charge/discharge
curves. Can't go by 'Ah rating' alone (since thats determined by a
20hour discharge)