Sorry to beat this horse. To clarify the engineering goals of the
Eco boost concept. DFI isn't there to increase mileage. Its purpose
is to reduce emissions below government mandates, earning greenie
points with regulators and the tree hugger market. It does that very
well. It does NOT contribute significantly to BSFC. The BOOST
component of the system provides some degree of on demand horsepower,
 while limiting the cruise combustion volume. If you drive a
conservative profile, you will see better mileage, but HP is there
when needed. HP is still not free, and there are no magic bullets of
physics, thermodynamics or chemistry. You will find that Paul is generally
correct, that BSFC for a given HP demand profile is not markedly
improved, while structures are lighter, more aerodynamic and the
engines are using simply more versatile and intelligent application
of technologies we already know and love.

Disclosure, I work for Ford.

Secret. look for a 5 cylinder something in the future.

C. Smith

Does DFI permit higher overall compression ratios for a given octane
rating?  That would improve BSFC.

SD


Check out Mazda's Skyactiv site. There is some video's of the different
concepts. DFI or in Mazda speak DISI is an integral part of the system to
lower the temperature in the cylinder of the air fuel mixture. The fuel is
injected while the intake valves are open. The higher pressure helps break up
the fuel into smaller droplets kind of like in a diesel.  The smaller droplets
evaporate more quickly which lowers the temp. A different exhaust to prevent
dilution with hot exhaust gases from another cylinder. The system is very
ingenious. USA customers will get 13:1 compression, Canadians will get 12:1 as
we are unwilling to pay for premium fuel. Other countries will get 14:1 which
will require premium. I tried to figure the cost to drive a tank of gas (400
miles, 600km) and compare the cost.I just used the advertised fuel efficiency.
It looks like it would be less expensive to burn premium and use less, thus
the fill-ups would be less $$. In these days, that is the bottom line for me.

Dale Davies