eer

[Clarence]

"CWatters" <colin.watters@pandoraBOX.be> wrote in message
news:QKl%c.239378$8O.12191801@phobos.telenet-ops.be...

"Jeff" <jeff@nospam.com> wrote in message
news:Xns955CE378BBB0Bjeffnospamcom@199.45.49.11...
But so what? If I drive my little truck at 65 MPH for 2 hours
at optimum RPM without using the brakes, I get maybe 25 miles
per gallon, which is nowhere near the 70 MPG of the hybrid at
the same speed.


If I can throw in a question here, has anyone got real world experience
of the hybrid ( specifically prius) mpg?

45-52 seem typical. Search for MPG on this forum...

http://priusonline.com/index.php?sid=e3fa38e41d13b0fe27745435a30291b0

You could tell her to pump the tyres up see....


http://priusonline.com/viewtopic.php?t=2138&highlight=mpg&sid=e3fa38e41d13b0fe27745435a30291b0

Interesting discussion.
I drive a NON-HYBRID GEO 3 cylinder, I gt 41 MPG in the city, and 47 MPG on the
highway. The price difference is over the amount you might save in the life of
the Car.

To quote the old lady in the commercial, "Where's the Beef?"

 

[Bob Myers]

"Clarence" <No@No.Com> wrote in message
news:Iqm%c.17110$FN6.2218@newssvr27.news.prodigy.com...

Interesting discussion.
I drive a NON-HYBRID GEO 3 cylinder, I gt 41 MPG in the city, and 47 MPG
on the
highway. The price difference is over the amount you might save in the
life of
the Car.

To quote the old lady in the commercial, "Where's the Beef?"

There isn't any; no one has claimed that a hybrid per se
is going to be HUGELY more efficient than a straight
gasoline-engined, conventional power train that is ALREADY
optimized for fuel efficiency and is in a small, lightweight
vehicle. It will still have some efficiency gains, but there's no
"magic bullet" that will let you extract 2-3X more MPG out
of a gallon of gas if you're already doing the rest of it right.

Bob M.

 

[Bill Bowden]

"Bob Myers" <nospamplease@address.invalid> wrote in message news:<zfl%c.9839$d23.3691@news.cpqcorp.net>...

"Bill Bowden" <wrongaddress@att.net> wrote in message
news:ad025737.0409061546.171612a7@posting.google.com...


Yes, aerodynamics and tire friction are big factors, but the question
is, why do hybrid engines obtain so much better efficiency with
changing loads? Do they change RPM to compensate for load?


The gasoline engine part of the hybrid power train
doesn't actually SEE that dramatically changing load;
that's the whole point. The battery (or, in some cases
a "supercapacitor" array) does just what the energy
storage or "main filter" caps do in a power supply -
smooth out instantaneous changes in the load such that
the primary power source sees a more-or-less steady
demand.

Yes, but the battery or capacitor will not sustain the
load of going uphill very far. The full load will
eventually be on the gas engine, which may not be
capable of climbing hills very fast.

That's why we need eer, so we have infinate storage capacity
and don't have to worry about climbing hills.

My truck always runs between 2000 and 3000 RPM, as do most other
cars, so that must be close to optimum, and it's a fairly narrow range.


It's burning the least amount of gas that it
could while still being capable of the flexibility you need of
it, but it's NOT as efficient as using a much smaller engine
that IS operating at or near its peak output all the time.

Good explanation, I wasn't thinking a big engine operating at
low power would be much different than a smaller engine
operating at full power, other than friction and weight.
The smaller engine would weigh less which would improve milage
and the larger engine probably has more internal friction which
decreases efficiency. Maybe there other factors.

Which do you think is more efficient, overall - a
conventional engine of, say, 150 HP max output that's
"loafing" at 2200 RPM (vs., say, a 5500 or higher RPM
point where that peak power is actually produced), or
a smaller, lighter, 30 or 40 HP engine that's running at
max output whenever it's running at all?

I vote for the smaller engine, but how long will it last
running at full power all the time? Isn't it subjected to
(more than normal) wear and tear running at full speed?

-Bill

 

[Bob Myers]

"Bill Bowden" <wrongaddress@att.net> wrote in message
news:ad025737.0409072032.54a0006c@posting.google.com...

Yes, but the battery or capacitor will not sustain the
load of going uphill very far. The full load will
eventually be on the gas engine, which may not be
capable of climbing hills very fast.

You're right - it won't sustain it very far. Properly
sizing the battery/capacitor/whatever - the "flywheel"
in the hybrid system - is one of the tradeoffs that has
to be made in the design of such vehicles.

That's why we need eer, so we have infinate storage capacity
and don't have to worry about climbing hills.

ROTFL...yeah, RIGHT. Don't tell me YOU'VE
gone over the dark side of Frank's delusions, too?

Good explanation, I wasn't thinking a big engine operating at
low power would be much different than a smaller engine
operating at full power, other than friction and weight.
The smaller engine would weigh less which would improve milage
and the larger engine probably has more internal friction which
decreases efficiency. Maybe there other factors.

But friction and weight are big deals! Look at the overall
efficiency of a typical IC engine, in terms of the total energy
released through the combustion of gasoline, and how much
actually makes it out of the engine in the form of mechanical
energy delivered to the rest of the drive train - and then see
where the losses occur. There's a LOT to be gained there.

I vote for the smaller engine, but how long will it last
running at full power all the time? Isn't it subjected to
(more than normal) wear and tear running at full speed?

Well, that would depends on what it's designed for
and how well it was designed in the first place, right?
And while "running flat out all the time" might at first
glance seem to be a Really Bad Thing for an engine,
consider the problems the engine faces in stop-and-start
driving as well.

Consider further some examples from those applications
in which engine weight and efficiency have been the
primary considerations, and NOT great flexibility in
operating speed and load - such as aircraft engines.
Both reciprocating (piston) and turbine (engines) in
aviation applications generally follow the "run flat out
all the time" model (well, not really "flat out," but
certainly close to the point of maximum overall
efficiency while cruising, and at a pretty constant speed.
Typical TBOs (time between overhaul) for piston
engines in light aircraft are generally in the 1500-2000
hour range; even if the AVERAGE speed of travel
over that period is only 100 MPH, you've wrung
150-200,000 miles of travel out of the engine. Yes,
this IS a very oversimplified look at this, but it does show,
I think, that running engines in such a regime is not
necessarily something that kills off the engine in short
order.

Bob M.

 

[CWatters]

"Bob Myers" <nospamplease@address.invalid> wrote in message
news:OCm%c.9876$Eb3.1404@news.cpqcorp.net...

It will still have some efficiency gains, but there's no
"magic bullet" that will let you extract 2-3X more MPG out
of a gallon of gas if you're already doing the rest of it right.

I don't think we expect 2x or 3x but the MPG figures seem to be almost the
same (perhaps only 10% better?). You can get better MPG by changing to a
diesel.

I can only think of three reasons to buy a hybrid car...

1) You care for the environment

...except if the MPG is the same it must be poluting the environment the same
(worse if you have heavy metals in the battery at the end of it's life?)

2) It saves you money

....except the saving doesn't seem to cover the increased cost.

3) You think they are cool.

....well I think all electric is cooler.

 

[E. Rosten]

Bob Myers wrote:

But friction and weight are big deals! Look at the overall
efficiency of a typical IC engine, in terms of the total energy
released through the combustion of gasoline, and how much
actually makes it out of the engine in the form of mechanical
energy delivered to the rest of the drive train - and then see
where the losses occur. There's a LOT to be gained there.

There's even more to be gained, when you look at how much makes it from
the drive train out to the wheels. With a design using wheel motors
(which are pretty cool, really), you can get away without having a drive
train, gear box and clutch which will all save weight as well compared
to a normal car, not to mention saving on drive train losses. From what
I've seen at the moment, wheel motors are still a bit underpowered, but
that should change.

-Ed


--
(You can't go wrong with psycho-rats.) (er258)(@)(eng.cam)(.ac.uk)

/d{def}def/f{/Times findfont s scalefont setfont}d/s{10}d/r{roll}d f 5/m
{moveto}d -1 r 230 350 m 0 1 179{1 index show 88 rotate 4 mul 0 rmoveto}
for /s 15 d f pop 240 420 m 0 1 3 { 4 2 1 r sub -1 r show } for showpage

 

[Bob Myers]

"CWatters" <colin.watters@pandoraBOX.be> wrote in message
news:ReV%c.241136$SN.12174445@phobos.telenet-ops.be...

I can only think of three reasons to buy a hybrid car...

1) You care for the environment

..except if the MPG is the same it must be poluting the environment the
same
(worse if you have heavy metals in the battery at the end of it's life?)

Maybe not; this assumes that the small, relatively
constant-speed engine of the hybrid is as difficult
to clean up as the conventional engine, and I don't
believe that's true. The battery materials should be
recyclable.

2) It saves you money

...except the saving doesn't seem to cover the increased cost.

Well, the conventional gasoline-engined car has
been around for about a hundred years now,
while hybrids, at least in their current incarnation, are
very new. I would have to expect that further developments
can decrease the cost of the hybrid relative to the
conventional drivetrain - in short, this factor should
change with time.

What's REALLY costly now is the full electric; the
only ones of those to even attempt to make a go of it
in the market have been heavily subsidized, and STILL
don't compete well.

3) You think they are cool.

...well I think all electric is cooler.

Why? A car is a machine for getting from here to there,
and unless there's something particularly obnoxious about
the behavior of the drivetrain, what's the difference between
a hybrid and an "all electric" - or among ANY choice of
propulsion systems - from any standpoint that impacts
"coolness" (whatever THAT is)? (If "coolness" were what
mattered, then I'll go for a gas turbine based hybrid, and
get that Batmobile whine....)

Bob M.

 

[Michelle Vadeboncoeur]

"CWatters" <colin.watters@pandoraBOX.be> wrote in message news:<ReV%c.241136$SN.12174445@phobos.telenet-ops.be>...

"Bob Myers" <nospamplease@address.invalid> wrote in message
news:OCm%c.9876$Eb3.1404@news.cpqcorp.net...

It will still have some efficiency gains, but there's no
"magic bullet" that will let you extract 2-3X more MPG out
of a gallon of gas if you're already doing the rest of it right.

I don't think we expect 2x or 3x but the MPG figures seem to be almost the
same (perhaps only 10% better?). You can get better MPG by changing to a
diesel.

I can only think of three reasons to buy a hybrid car...

1) You care for the environment

..except if the MPG is the same it must be poluting the environment the same
(worse if you have heavy metals in the battery at the end of it's life?)

Currently available hybrids (Honda Insight, Honda Civic hybrid, Toyota
Prius)
all use NiMH (nickel-metal hydride batteries), which do not contain
any
heavy metals. The 12v accessory battery is usually a bit smaller than
you'll find in traditional cars, and is the same heavy-metal PbA lead
acid battery that all other traditional cars have. Both NiMH and the
12v PbA batteries are easily recycled. (Toyota pays a $200 "bounty"
to dealers to make sure that they recycle batteries in the event that
it needs to be done, say when dismantling a wrecked Prius for parts.)
I believe the Ford Escape hybrid, the Lexus RX400H (hybrid RX330, and
the Toyota Highlander hybrid are all again going to have NiMH hybrid
batteries, too.

As for polluting the environment, it depends on what pollutants you
are
looking for. CO2 (carbon dioxide) emissions is directly proportional
to MPG. However,
CO (carbon monoxide), NOx (nitrous oxides), HCs (unburt hydrocarbons),
and particulate matter depends on how clean/efficient the vehicle's
engine/exhaust/fuel system is. While a manual transmission VW TDI
(diesel)
may be able to get similar MPG to a manual transmission Honda Civic
hybrid,
the HCH can qualify as a AT-PZEV in California (SULEV with no
evaporative
emissions), while the VW TDI until this year couldn't be sold in CA
because of the diesel's filty emmisions (partially thanks to the dirty
diesel fuel sold in the US). For more information, I suggest reading
the EPA's Green Vehicle Guide: http://www.epa.gov/greenvehicle

 

[FEerguy9]

That's why we need eer, so we have infinate storage capacity
and don't have to worry about climbing hills.

ROTFL...yeah, RIGHT. Don't tell me YOU'VE
gone over the dark side of Frank's delusions, too?

BOOOOO!!


fRANK