Paul,

Published in the October 2009 issue of Automobile.

Two engine technologies- turbocharging and fuel injection- have recently
joined forces in mechanical matromony.  Spraying the fuel directly
into the combustion chambers achieves more precise mixture control,
since no droplets are left behind on the intake port walls, injecting
the fuel at 2000 or so psi versus the 50 psi common with port injection
facilitates finer atomization and more complete vaporization.  Also
the cooling effect from the fuel's change of state from liquid to vapor
enables significantly higher compression and expansion ratios.  According
to the EPA, the net improvement in efficiency attributable to
  direct  injection with turbocharging is a substantial 12 %.

Who has it:BMW,Bugatti, Chevrolet,Ford, Lincoln, Mazda, Mini,
Porsche,Volkswagen.

I checked with Mazda in Missoula, MT and they never heard of it.

Gene Sandburg

I'll believe it when I see it/ Direct injection in a gasoline
  engine is not  easy. They have talked about it for years. Mercedes
  had direct injector  50 years ago in their race cars. Formula 1
  engines would have direct  injection if it did anything and they don't.

Porsche spent big bucks on R&D and the improvement was barely noticeable.
It is also very expensive.

Paul Lamar

Paul, reguarding direct injection on aircraft engines. It would
  have the same $2500 fuel pump as a diesel and likely need a
  mechanical volume metering system to fire at 6000RPM. I could see
it  working on a piston engine although mixture control would be
 tedious. From what I have read it is necessary to mist the fuel
near  the ignition source to produce a stratified charge. This
allows a  leaner mixture overall for the entire charge and a faser
burn with  much of it occuring near the plug in the enriched area of
the  stratified charge, The rest of the volume provides additional mass
  of air to heat for expansion pressure.

  In the case of a
  rotary running at near maximum power we need the oil mixed in the
  fuel for lubrication. If the direct injection is a stratified
charge  system there is almost no exposure of the side and apex
seals to the  oil and without lubrication even ceramic seals  will
not IMHO  survive. I know that Mazda is working on a direct
injection follow  on to the RX8 series with the 3 injector oil
metering system they  now use. The metering pump seems reliable to
run along at 65 MPH at  reduced power with only short seconds of
acceleration power  but  this is a car engine.

  I would be surprised  if Mazda
  ever  raced anyhing that didn't have oil mixed fuel. If the goal is
  not the fuel efficiency of stratifierd charge what possible benefit
  is there to direct injection.. Introducing the fuel in the  intake
  runner gives a lot more time for the fule to vaporize and cool the
  intake charge. I am not sure what fuel pressures are these days in
  multipoint car injection, but I think 70 PSI should be close. In
out  sprint car we has 220PSI at  the inlet of the barrel valve and more
  than that at the injectors when the valve was turned open. These
  were constant flow systems running methanol as fuel and we thought
  fuel burn was good for a 750 HP engine.

  We used a high system
  pressure relief valve and two drip in orfices "pills" before and
  after the barrel valve for idel and max power fuel metering. the
  barrel valve linked to the throttle plates  controled the fuel
after  idle to full power. This was by todays standards crude as a
club,   but fairbanks wasn't making integrated circuits at that time
and  aircraft radios used tubes and crystals for tuning.

  Now we have EFI with the possibility of changing charge density
  by  timing the beginning of the pulse so that an enriched mixture
is  around the plug when it fires. It would appear that a p-port rotary
  with an optimized port shape and the fuel sprayed by two injectors
  near the top and bottom of the port could produce a sratified chargefor
  a rotary . engine running at a near constant RPM. The goals
  would be to reduce swirl mixing and introduce the fuel during the
  most laminar flow into the rotor chamber by adjusting the beginning
  point of the fuel pulse timing.

  george grimes

Hi folks,
I purchased a '09 Mazda 3 this spring. It has the MZR 2.3L DISI
engine. It comes with 4.1 final drive so revs are  about 2750 at
110Kph (68 MPH). A bit high to my mind but goes up hills in cruise
without batting an eye.  To check the direct injection, Google mazda
DISI. Select www.mazda.com/mazdaspirit/env/enginedisi3.html  Just
click the red box when the install language nuisance comes up. There
is an animation of the combustion. Select 2.0L DISI. There is also
one about the Millar cycle which I believe Crower played with 25
years ago. Did not work as well as without VVT. Suppose you injected
a small amount of fuel into the area of the spark plug, with a very
lean mixture in the main combustion chamber of a rotary. Think
diesel pre-combustion chamber. The rich mixture at the spark plug would
ignite when the rest is too lean to ignite. The flame once started would
then propegate to the lean mixture. Combine with turbo compound to regain
lost power to the lean burn. Just a thought.

Dale Davies

Does it get better gas mileage than a Honda or Toyota?

CW, John Deere and RPI fooled with this for 30 years.
Never got it to work worth a damn.
http://www.rotaryeng.net/Stratfied-charge-rotary.pdf

Paul Lamar


Hi Paul,
I am not sure whether it gets better economy than Honda or Toyota. I am
getting 32 to 37.3MPG US. I try to keep the speed down to 90KPH or 55MPH.
Economy drops off fast as the speed increases. This is a 5spd car. From the
animation video, I presume one of the big advantages is emissions as
contamination of the exhaust with raw feul is elliminated. That is likely
the motivation on the 16X engine. The previous stratified combustion
attempts did not have the benefit of the EFI systems available today. Not
saying that is the total answer to the problems that are presented, but the
modern electronics do give a lot of flexability.

As an aside, I have concerns with the H2 push. Hydrogen is combustible from
5% to 90% in air. And it is a smaller molecule that present technology can
not contain effectively. Cell phones and refuelling could be a problem.

How lean could gasoline combustion go if started with a "pilot flame"? In
the link you posted, it speaks of homogenous fuel mixture. Sounds like
Smoky Yunicks adabiatic or hot air technology to me.

Dale Davies

There are a lot of good tech papers to read on the web site.

Paul Lamar