Billions have been spent on direct injection so far with little or
no benefit other than diesel engines that need direct injection
anyway. Tons of stuff has been tried including warming the fuel.
Porsche just went through the exercise yet again. Don't hold
your breath.

The R&D money would be better spent on turbo compound
which is a well proven technology. Proven to reduce the fuel
consumption 20% because it focuses on recovering some of the
largest  waste of fuel in the world. Well over half of the total
transportation fuel burned in the world today goes out the exhaust
as waste HP.

Paul Lamar


Paul,

While this system sounds bogus, as you pointed out, direct-injection on
gasoline engines is not. The additional cooling effect of DI, applied
immediately before combustion, reduces knock sensitivity sufficiently to
allow about a compression ratio about 1.5 points higher. That's worth two or
three percent in fuel efficiency, and bit more power and torque as well. If
you downsize the DI engine to hold output constant, you might find another
couple of percent for a total of perhaps five.

That's not earth shaking, but it is worthwhile, which is why just about all
automotive gasoline engines will be direct injection within five years.

Csaba

It has been around for long time. As far back as the MB 300SL.
In WW II aircraft the DB601 V12 in the ME109.

What has changed?

Paul Lamar


Paul,

The application of electronics to DFI has only been around for a few years
(I think Mitsubishi was first with this technology in the late Nineties).
The more precise control of the fuel metering and the timing of its
injection has allowed the cooling benefits of DFI, relative to port
injection, to be realized.

Also, in Europe, they run lean with DFI for further fuel economy benefits.
They can do it there because their tailpipe emission laws are less strict
than ours and because they can use a lean-burn NOX catalyst that won't
survive America's higher-sulfur gasoline.

There's no question about the increase in compression ratio with DFI
engines. When the Porsche 911 got DFI, the compression went from 11.3 to
12.5. Even my BMW 335i, which is turbocharged with DFI, has a 10.5
compression ratio. There's a payoff with those increases.

Csaba

I  agree but lean burn is a whole separate issue as we say in Cal :)
You can lean the engine without direct injection. The RX8 engine
is also 10:1 CR.

Haagen Smit the father of smog got angry back in the late 60's
when the  US gov limited both NOX and Hc. His contention
was limit Hc but not NOX for the reason you stated. The
European pax car diesel proponents are trying to jump through all
sorts of hoops to limit nox and still sell diesel cars in the US.

Here is an OCR quote from the book The War Against the Automobile
B. Briggs in the chapter on Emissions which I am sure you have
in your library.

Quote:
"But better combustion also results in more combination of
nitrogen with oxygen, producing NOx' The nature of operation
of the Otto-type internal-combustion engine, used in almost
all cars in the world, precludes eliminating both hydrocarbons and NOx.
Now the reader may reasonably ask this question: If the smog
is caused by the combination of NOx and hydrocarbons, why
is it necessary to get rid of both of them? That is an
excellent question.

The father of smog, Professor Haagen-Smit, said "the Muskie [DEM]
bill passed last December [1970] without Congress understanding
that emissions in 1970 vehicles had already been controlled
70 to 80 percent." He described the EPA air quality standards
for hydrocarbons as "absurd."
End quote.

Beck would say it was a attempt by the commie green radicals
to obtain more control over the individual.
I felt that years before Beck and wrote a letter to CARB
to that effect :) I may have it someplace. Ah yes here it
is sent to Cal Air Resources Board in 1999.

Paul Lamar Wrote:

" The EPA/CARB would be entirely happy if no one could afford a car
  and they had to take public transportation in stinking buses
  that emit carcinogenic particulates and be subject to muggings and
  rapes and have to sit in other people's shit.

  The EPA/CARB would also love it if everybody had to walk to work
  or ride a bicycle.

  In fact the EPA/CARB resents the freedom and anarchy that people enjoy
  by owning a car. The EPA/CARB also resent the fact that some can buy
  better cars than others and that cars can be used as status symbols
  to indicate that some people are perhaps better or more wealthy
  than others.

  Do you see a little conflict in the implementation of the EPA/CARB
  goals here?

  The failure of the modern electric car stands as a monument to
  the stupidity of the EPA/CARB.

  All other possible solutions to the air pollution problem have been
  cast aside such as population density control in favor of
  focusing all efforts on the passenger car as the passenger car
  owners are not politically well organized.

  As far as population density control is concerned the EPA/CARB
  would like it if everybody lived and worked in one huge high rise
  skyscrapper and owned no cars to drive to the pristine and deserted
  mountains and sea shores.

  In my humble opinion the EPA/CARB have far too much autonomous power
  and are almost as bad as the IRS. Perhaps the EPA/CARB just have an
  image problem." :)
End of quote.

My English is a tiny bit better now :)

We run the A/C rotaries as much as 200 degrees F lean of peak.
The BSFC drops from about .52 or so down to .47. Every pilot
flying any kind of airplane is taught this.

I contend the BSFC on the rotary can be improved by sparking
it over a wider range of e-shaft angles. As soon as I get
my dyno done I will test the idea.

Another idea is use the tiny PC based EFI I am working on now
to use EGT as a feed back signal to control the lean mixture.
It is a question of which side of the EGT curve you are one.

BTW Know anybody that will work for a pitance and can live in my
hangar for free that is capable? :)
Must be able to fabricate, use a lathe, use a mill and tig weld.

Paul Lamar

-

Paul,

I don't disagree with much of your arguments with EPA, but the fact is that
modern cars are extremely clean, producing less than one percent of the
three major pollutants that cars of the Sixties did.

But back to DFI, the compression ratio increase with DFI is real. The RX-8
might have a 10.0 to one ratio, but the BMW 335i has 10.5 and it's
turbocharged.

Here's a brief list of the compression increases achieved when engines
switches to DFI:

Audi DOHC V-8    11.0 to 12.5
GM 2.4L DOHC 4    10.4 to 11.4
GM 3.6L DOHC V6    10.2 to 11.3
Mercedes 3.5L DOHC V6    10.7 to 12.2
Porsche Cayenne 4.5L V-8    11.5 to 12.5

These increases are real  and while they won't achieve huge bumps in
efficiency, they will deliver 3-4 percent.

Every little bit helps.

Csaba

Yes I would argue cleaner than necessary. They could back off
on the Nox restrictions , lean the engine and improve the BSFC.

As far as compression ratio is concerned the piston engine has
an advantage. As far as turbo compound is concerned the rotary
has the advantage as the kinetic energy in the exhaust, due to the
lack of exhaust valves, is twice as high. Twice the energy for the
power recovery turbine. Higher CR 1% to 3% improvement.
Turbo compound engine... 15% to 20% reduction in fuel burn.
Now that IS earth shaking Csaba  :)

Here is a Kit Plane article on the subject you may not have
seen or read. I am working on another article for EAA Sport
Aviation mag.

Here is a video of the presentation I gave on the subject
at the World MotorSports symposium.

http://www.rotaryeng.net/Oxford-640-4802.wmv

You may recognize some of these people as most
are engineering directors for many Formula 1,
Nascar and European endurance racing teams.

I may give another presentation on the subject
at Aero in Friedrichshaven in April.

Here is a list of my youtube videos on the subject.
http://www.youtube.com/watch?v=KcqP3U1tAPc
http://www.youtube.com/watch?v=6Po5jsrYMK4
http://www.youtube.com/watch?v=bkWbsO0C8x8

Paul Lamar