Direct injection reduces the amount of fuel that
may escape the combustion chamber. Direct injection
may also provide more fuel rich areas surrounded
by air. Jet ignition may ignite main chamber
premixed fuel and air with very high energy
all across the chamber or in a selected region as
well. Direct injection and jet ignition carefully coupled
may permit completely throttle-less load control,
with the main chamber fuel air mixture restricted
to a selected area where the jet ignition
would start combustion that will complete almost instantaneously.
In the latest developments, jet ignition
and direct injection are coupled together to modulate
the amount of premixed and diusion combustion
to achieve the best trade-o of fuel conversion e-
ciency and pollutant formation all through the speed
and load range. CNG is the fuel considered in the
exercise.