sure, but in reality the major work performed in
the cylinder is concentrated in a lesser portion of
the piston travel.
This condition can be compared with a steam
engine using high steam pressure with a very
short valve cut-off. In a combustion system of this
design, the fuel injection valve is inconveniently
located in the center of the cylinder head.
rating the controlled turbulence chamber removes
the foregoing disadvantages in engine operation.
As shown in the illustration, a spherical water
cooled combustion chamber is cast integrally with
the cylinder head, and a throat connects this
chamber with the cylinder combustion space.
During the compression stroke the air is forced
into the chamber, entering tangentially at high
velocity and producing vigorous turbulence. Fuel
oil at considerably lower pressure is sprayed into
the combustion chamber through a multiple ori-
fice spray nozzle which has comparatively large
openings. The injection period is twice as long as
that in a direct injection system. The fuel spray
mixes rapidly and thoroughly with the turbu-
As combustion proceeds, the pressure rise per
degree of crank travel is only about 26 Ib per
sq in. The maximum combustion pressure is
thereby held to a conservative figure. An indi-
cator diagram of this action will show a relatively
lower pressure rise at the end of the compression
stroke and a broader power or expansion curve.
This develops a higher mean effective pressure
with the benefit of low compression and combus-
tion pressures, and, again in comparison with the
steam engine principle, is similar to the use of
lower pressure steam with a longer steam cut-off.
provides uniform clean and efficient combustion,
is less sensitive to variation in fuel oil character-
istics, and consequently can burn lower grade,
The water cooled combustion chamber sepa-
rated from the cylinder proper provides protec-
tion for the piston rings and exhaust valves from
the intense heat to which these parts are exposed
in other systems where the combustion chamber
is the clearance volume between the piston and
the cylinder head. Thus the more common trou-
bles such as clogged spray valves and sticking
piston rings are avoided.
Many years of experience have proved that
Diesel engines equipped with a controlled turbu-
lence combustion system operate more smoothly,
quietly, and with a minimum of maintenance cost
and service interruptions.
WITH THIS exclusive combustion system, De La
Vergne Diesel engines are less sensitive to variations
in fuel oil characteristics, without sacrifice of clean,