> > Haven't you noticed they operate near the
 > > full load point a tiny fraction of their lives?
 > > Hold the pedal down in a car and you get a speeding ticket long before
 > > any TC efficiency payback.
 >
 > > Don Sherman
 >
 > ------------------------------------------------------------------
 >
 > Depends on the size of the engine. A Prius engine is flat out at 80 MPH.
 > If the battery was charged to begin with it is soon dead or switched off
 > before it is dead.
 >
 > The smaller the car engine the higher the duty cycle. Yes of course a
400 HP
 > Corvette is using a tiny fraction of claimed HP. Using a smaller
engine is
 > called "down sizing" and yes indeed it does improve the MPG as the
 > engine is
 > more closely operating in the best BSFC island. First two charts.
 >
 > If the engine is 50 HP flat out to improve the BSFC by 10% all you
need out of
 > the turbine is 5 HP. At 100,000 RPM that is .26 foot pounds of
turbine torque.
 >
 > If you take a look at this next chart you will notice that even a fully
 > loaded truck is not using max power at a steady 70 MPH. California
has a truck
 > speed limit of 55 MPH in many places. At 55 MPH a fully loaded truck
is using
 > about 50% max power. Aerodynamic drag is a major factor.
 >
 > Next to the last chart is the BSFC chart for gas engines verses
diesels as a
 > percentage of max power.
 >
 > Paul Lamar
 > -------------------------------------------------------------------------
 >
 > Paul, with all of your expertise, why don't you apply for some of the
 > grant money being thrown around for energy and efficiency research
projects?
 > C. Smith
 >
 >
-------------------------------------------------------------------------------
 >
 > I am too old to go back to work. I'll be glad to work with somebody for
 > free if
 > they decide to do that. I have already mentioned that to Eric at
Rotamax as
 > they
 > have the credibility of already being a U.S. rotary engine
manufacturer with a
 > complete machine shop and dyno. So far no word on if or when this
will happen.
 > If Mazda did it I would also be glad to help.
 >
 > Due to a lack of exhaust valves the turbo compound rotary is
potentially the
 > most efficient internal combustion engine of all. A marriage of the best
 > features of the intermittent and continuous internal combustion
engines. Once
 > the turbo compound rotary reaches 50% efficiency there is no point to an
 > electric car or rail transport unless the nation switches to nuclear
energy.
 > The
 > reason for this is the majority of electric energy generated in the
U.S. is by
 > power plants burning coal, oil or natural gas. Transmission lines are
not 100%
 > efficient.
 >
 > The maximum local efficiency of these power plants is about 50% this
in the
 > case
 > of a bottoming cycle gas turbine. A bottoming cycle gas turbine is
sort of a
 > turbo compound power plant where the waste heat from the gas turbine
makes
 > steam
 > that is fed to a steam turbine. Most other electric generating power
plants are
 >
 > not 50% efficient. Look it up in Marks "Standard Handbook for Mechanical
 > Engineers".
 >
 > Paul Lamar
 >
 >
 > Paul, I think the rotaryTC/hybrid idea is the best option for an
automotive
 > powerpalnt as well. At Ford there is a website for posting ideas that
could help
 > the company, and I did post a note about the rotary TC, and with
Ford's ties to
 > Mazda, that could be the foundation for a joint project. An engineer
replied
 > that it would be nicely suited in a hybrid, and we all know the
reasons why. But
 > that's as far as it went as I can tell.
 >
 > August issue of Control Engineering, Page 36, article titled "The
Hunt for
 > 60+% thermal efficiency" Frank J. Bartos. speaks to your points
precisely.
 >
 > go to www.controleng.com/archive <http://www.controleng.com/archive>.
 >
 > At any rate, I marvel at the degree of technical expertise discussed
here
 > on this list, if only our politicians and the general public could
grasp some of
 > the reality of the physics and technological challenges facing us
while we seek
 > solutions to our energy
 > woes.
 >
 > C. Smith
 >

Dear Paul and Group:

I think Mr. Sherman is right on when he writes:

"Haven't you noticed they operate near the full load point a tiny
fraction of their lives?  Hold the pedal down in a car and you get a
speeding ticket long before any TC efficiency payback."

Which leads me to my second basic problem with turbocompounding in
automobiles: Efficiency.

In my post, "Starter alternator? Turbocompounder!" I suggested a way to
conquer the first basic problem with turbocompounding: Time.  There I
suggested we completely decouple the power generation of the
turbocompounder and that of the rotary engine.

To tackle the second problem of turbocompounding, Efficiency, I suggest
we entirely decouple the _delivery_ of the power from both sources: both
from the rotary engine and from the turbo compounder.

What do I mean by that?  In automobiles, the need for power goes up and
down.  Old ways of dealing with that involved connecting the engine
mechanically to the wheels.  So, because the engine is shackled to the
wheels, we had to make the engine rev up and down.  To make the car more
powerful or efficient, we sought to make the engine powerful throughout
its rev range.  Yet turbocompounded engines reach their peak efficiency
at a narrow, high rev band, just as Mr. Sherman noted.

So, do not use the old mechanical connection of the engine to the
wheels.  Decouple the engine from the wheels.  Let the turbocompounded
rotary engine always run in its high-rpm, most efficient rev range.

Instead of connecting the engine mechanically to the wheels, connect
them via hydraulic fluid or electricity.

Please!  This is not a "hybrid"!  "Hybrid" has lost its meaning and has
been devalued into a marketing term to get people to give companies
money.  "Hybrid" used to mean, in this context, "using more than one
means to power the wheels."  So, sometimes the gasoline engine powered
the wheels, sometimes the electric motor powered the wheels.

This is not a hybrid.  The drivetrain handles the up-and-down variations
of speed of the vehicle.  The engine generates power for the
drivetrain.  This it does by operating at its most efficient level.  All
of the time.  The turbocompounder, decoupled from the rotary engine,
also makes power, at its own most-efficient speed.  Separate chargers
take the energy made by the e-shaft and the turbine shaft and put it
into the transmission system.  When the rotary/turbocompounder has fully
charged the transmission system, it stops. When the transmission system
needs to be recharged, it starts again.

Hydraulic transmission of power is much more power-dense, cheaper, and
quicker to convert potential power to kinetic energy.  Here are some
excerpts from DesignNews.com:

"That accumulator drives a bent-axis pump-motor on the rear wheels to
propel the vehicle. A low-pressure reservoir completes the hydraulic
circuit, collecting the fluid before sending it back to the first
pump-motor.

"Like electric hybrids, hydraulic hybrids also provide regenerative
braking capabilities. During braking events . . . the pump-motor charges
the high-pressure accumulator. The energy stored in the accumulator can
be used . . . when the (vehicle) moves forward again.

"To consumers and even some engineers, hydraulics may seem like outmoded
technology in an increasingly electronic world. Yet hydraulic
pump-motors and accumulators can provide a low-cost, reliable way to
apply torque and store energy which is exactly what hybrid vehicles
require. And hydraulics offer a significant power-density advantage over
electrical systems, at least for now.
 . . .
"Aside from the cost and weight of the system itself, though, hydraulics
have something else going for them power density. Nothing out there
beats hydraulics when it comes to power density, says Kovach, who
explains high-pressure accumulators and pump motors have at least 10
times the power density of batteries and electric motors. Ultra
capacitors, in theory, can get pretty close from a power density
standpoint. But theyre still way too expensive in these applications,
says Kovach, who estimates an ultra capacitor of the size needed for
these heavy-duty vehicles would cost around 50 times as much as an
accumulator that does the same or better job.
 . . .
"Kargul maintains hydraulic hybrids are much more efficient at
recovering braking energy. He says a hydraulic hybrid with a properly
sized accumulator ends up returning about 70 percent of the braking
energy to the wheels while a typical electric hybrid returns something
around 21
percent."(http://www.designnews.com/article/1152-Hydraulic_Powertrains_Propel_These_Hybrid_Trucks.php)

"Power density" sounds an awful lot like "rotary engine".  A power-dense
engine driving a power-dense transmission.

A hydraulic system would get my vote for how to power the wheels.  Yes,
hydraulic transmission has problems (""[They] groan like the landing
gear on an airplane," admits Kelly of BorgWarner.
http://www.businessweek.com/magazine/content/06_38/b4001082.htm) but
these problems can be solved.

We can attain Efficiency with a turbocompounded engine in a car.  We
just have to think (and transmit) out of the "automatic" box our minds
stay in. :-)

Les Nordman :-)

Similar electric drive systems are used on off road vehicles such as locomotives and earth moving equipment.

The problem with all of these schemes is nothing is 100% efficient.
For a simple example let's say the generator is 90% eff. and the electric motor driving the wheels is 90% eff.. The over all drive eff. then becomes 81% eff. Now we start with a diesel  engine which is 40% eff. We are now down to 32.4 % overall. The same thing happens in a hydraulic system. The hoses resist the flow and the pumps and motors are not 100% eff. You get the idea.

This principle applies to electric cars as well as the electricity is probably generated by an internal combustion engine some place and is then transmitted miles over transmission lines that are not 100% eff..  The electricity from the power lines is then converted to battery charge which is also not 100% eff.. Then it goes to a motor which again is not 100% eff.. The fundamental problem is the resistance of wire to current flow.

The fact of the matter is there is no beating gears for max eff..
The Formula 1 organization is implementing KERS. Kinetic Energy Recovery System that stores braking energy in a flywheel. The flywheel is located in a vacuum chamber so aerodynamic losses are eliminated. In theory this is far more eff. than the schemes mentioned above as only gears are involved. Also I might add a flywheel can store more energy per pound than any battery on the horizon.
The only thing that exceeds a flywheel in energy storage per pound is a rubber band.

http://www.rubberbandit.org/

Paul Lamar

Very well put Paul. Last week I rode in one of those DOE funded hydrogen
fuel cell small cars. When I got in it was parked and off. Guess what I
heard ? The sound of a high frequency from a blower in the trunk....
sounded like a blow dryer was embedded in the rear seat head rest. This
continued when we went for a ride and after we were done. So, this so
call highly efficient ELECTRIC car (with a chemical gas operated
battery) was leaking energy to cool the fuel cell.  I've never seen
these losses published anywhere. Nor have I the losses from the freon
(OK, R-134 something) lines running through the Toyota synergy hybrid
battery pack to cool it.

-Anonymous