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Патент USA US2105717

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Jan. 18, 1938.
w. s. B'URN
Filed Nov. 13. 1935
tastes ass. is, rss
attain -
. $15K
Walter Scott Burn, Hartlepool, England, assignor ,
to The National Gas and Oil Engine Company
Limited, Alfred Bickerton Balmford, Ashton
under-Lyne,‘England, and Walter Scott Burn,
Hartlepool, England
Application November 13, 1935, Serial No. 49,632
In Great Britain November 18, 1934
60laims. (Cl. 123-65)
This invention relates to internal combustion in Figs. 1 to 4, and at the same time tangentially
engines and aims to provide means for producing as shown in Fig. 6.‘ A valve controlling admis
better results in exhausting or scavenging the sion of air to ‘the belt 3 is represented diagram
matically at 5, the same operating mechanically
compression cylinders thereof.
i The problem of exhausting the cylinders of or automatically in practice. The exhaust ports 6
internal combustion engines is still the subject of 2 are similarly inclined toward the combustion
end of the cylinder, but instead 01' being all in- .
much atttention notwithstanding the various ef
forts made to solveit, because it is generally clined in one sense tangentially, they are divided
recognized that there is room for improvement. into two sets, one set being inclined tangentially
,0 The present invention hasfor its object to attain in a sense opposite to that or the other as shown 10
or enable better results to be obtained than has '
heretofore been ‘possible, particularly in single
.acting two stroke oil engines. This is achieved
by a cylinder exhaust system consisting of two
5 complete or approximately complete circumfer
valve. 5 being closed. Fig. 2 similarly indicates 15
the conditions which exist a little later when the
piston has descended further and the valve 5
opens and scavenging commences. In Fig.3 the
exhaust gas has been largely displaced by scav
enge air and supercharging has commenced as 20
the piston starts upward again. Fig. 4 represents
the supercharging further advanced as the piston
nearly covers the scavenge admission ports.
The improved system possesses the following
ports occupy the full circumferential width avail
used for admission of scavenging air juxtaposed
The exhaust or lower ports are arranged to per
;0 mit the easiest possible flow of gas to the ex
haust belt and exhaust main which is located at
one side of the cylinder, although said exhaust
Fig. 5.
Fig. 1 indicates by arrows the exhaust gas leav
ing the cylinder as the descendng piston uncovers
the exhaust ports, the scavenge air admission
ential rows of ports, 1. e. an upper row which is
to a lower row of exhaust ports. >
The upper row of ports for admitting the scav I advantage features:
enging air are the terminations of nozzle ports
First, a de?nite stability of action. That is,
the air jets issuing from the ports I are not only
which are inclined upwards toward the combus
tion end of the cylinder but with a tangential highly developed from, a nozzle port point of view
component. A suitable valve, operated mechan
to give a concentrated directioned ?ow, but short
ically or automatically, shuts o? the scavenge air ly after leaving the ports the scavenge air streams
ports from the air supply until the exhaust ports as shown in Figs. 2 and 6 are made to impinge
have been opened by the piston and the pressure diagonally onto the cylinder walls, 1. e. they are
within the cylinder is reduced to below that of to strike the cylinder walls substantially tan
the appertaining scavenge all’v pressure. The gentially, circumferentially and with an inclina
valve then opens and air is admitted until the tion axially in such manner that a de?nite .guiding
exhaust products are expelled and in addition a eii'ect is given to the air streams by the cylinder
predetermined amount of supercharge air is walls and consequentlypthe air streams ?ow in
helical paths very similarly to that of a multi
forced into the cylinder. _
threaded screw. The centrifugal or swirling ef
The manner in which the invention can be car
ried into effect will be more readily understood fect of the rotating air, with its higher density
.from the description now about to be given with relative to the cylinder contents of exhaust gases,
the aid of the accompanying drawing, in which de?nitely tends to localize the scavenging action,
Figs. 1, 2, 8, and 4 are diagrammatic views of a the air tending to remain outwards adjacent the
cylinder, piston and air control valve, each with ‘cylinder walls with its movement oi’ rotation and
the partsin a different position. Fig. 5 is a hori
translation, thus causing the exhaust gas to be
zontal diagrammatic section taken at the ex
expelled down the centre'of the cylinder by dis
haust belt of Fig. 1, and Fig. 6 is a similar section placement, this latter being represented by the
taken at the scavenge air belt of Fig. 2. Fig. '7 arrows at (see Fig. 2). In other words, the gen
is a diagram illustrating the conditions in the eral air and gas movement is upwards at the
cylinder at the end of the compression stroke.
cylinder sides and downwards at the cylinder
In the ?gures, the ports for admission of scav
enging and supercharging air are represented at
Second, the inside top of the cylinder, or the
l, ‘and the exhaust ports at 2. The ports I are bottom of its cover, is made to present a shape
inclined upwardly, from an air belt 3, towards ‘represented by the curve 1/ (see Fig. 1) such as
the combustion end 4i of the cylinder as shown $9 aid. reversal of the air ?ow after it has reached
2, 106,717
the combustion space end of the cylinder, the
tendency also being, as represented by the ar»
rows .121 (see Fig. 3) for the conical angle of the
exhaust gas beneath the air streams to increase
named row; the scavenging air ports being ter
minals of nozzles which are inclined toward the
combustion end of the cylinder with a tangential
component with relation thereto. and said valve
controlling the supply oi’ scavenging air to admit
it only when the row of exhaust ports have been
uncovered by the piston so that the pressure
within the cylinder is reduced below that of the
or ?atten out after the air has reached the com
bustion end of the cylinder until the exhaust gas
is expelled and the engine cylinder is filled with
fresh rotating air.
~ 7
Third, as the scavenge air ports -I ‘are in process
' scavenge air supply.
10 of being cut of! by the piston, (see Fig. 4),.the
vertical or axialcomponent of the air stream near
to the cylinder walls increases and the up and
down action increases, thereby tending to‘ create a
vortex ring during the ‘compression stroke, which
15 is a favourable form 01' organized air movement“
especially if the fuel valve is disposed within or
at the centre of this vortex ring, which is pre
ferred, the ‘fuel sprays being directed in an ap
4. An internal combustion engine comprising a
cylinder having two separate and complete-cir
cumferential rows of ports at different levels be~
low the top and an inner topshaped to present
an ‘approximately double concave surface to the
combustion space, the upper row of ports nearer 15
to the cylinder top being tangentially and up
wardly inclined so as to cause entering air streams
to. how uniformly upward and around in helical
proximately horizontal manner and sprayed out paths against the inner wall of the cylinder to
20 wards from ‘the cylinder centre, as contemplated ward the top and the inner top surfacing caus
in Fig. '7,
ing it to then reverse and ?ow downward again
centrally of the cylinder inside the area 01' initial
Fourth, the exhaust and the scavenging ,alr
ports 2 and i respectively, being arranged ,with‘a
maximum circumferential’ width, give a maxi
mum port area with'a minimum of axial length
?ow of the entering air streams, thereby stabiliz
ing the flow oi‘ the scavenging air and permitting
the same ports to be utilized for ‘supercharging, 25
61' port,lwh.ich in the_case of the exhaust ports ' and a‘ valve controlling the air‘ entry through
2 is particularly important to get the maximum
of useful expansion? and compression stroke.
said upper ports by a timing arrangement opening
tion of the scavenge ports above‘ the exhaust ports
inder having a circumferential row of exhaust
ports below the top level, a circumferential row
the same to air admission only after the lower
Finally, from both the point of view of obtain- . row has been opened to gas exhaust; the said
ing a maximurn'of initial _air charge with a mini-v lower row of ports being also upwardly and some 30
mum of scavenging air, and also having the maxi what tangentially inclined to the cylinder axis.
mum of expansionlstroke', the described disposi-.
5. In an internal combustion engine, a cyl
2 is decidedly advantageous. V , '
_What I claim is:-
1. An internal combustion engine cylinder hav-V
' - of scavenging air admission‘ ports above the level
ing a complete circumferential row of ports for
admission of scavenging air and ajuxtaposed
circumferential ro‘wof- exhaust ports more re-.'' mote from the combustion end of’ the cylinder,
both of said rows of ports being adapted to be
of the exhaust ports; both of said rows of ports
being opened and closed by piston movement,
and a _valve controlling the air admission ports
operated in timed‘ relation to the piston so as to
admit scavenging air through said ports only 40
after the exhaust ports therebelow have begun
covered and uncoveredby the same piston work- _ to. open and shutting oil’ the air supply again
ing in the cylinder; the scavenging air ports be- . vonly after said exhaust ports have been again
ing the termination of nozzles-‘which are in-' closedr the said air admission ports being
clined toward the combustion end of the cylinder terminals of nozzles extending through the cyl
and having a tangential ‘component with respect inder walls from a surrounding belt chamber with
an inclination toward the combustion end 01’
' 2. An internal combustion engine cylinder hav
the same and‘ having a tangentialcomponent
ing two approximately complete circumferential ,. with relation thereto.
50 rows of ports one below the other, the upper 01'
6. In an internal combustion engine, a cyl 60
said two rows being for the admission of scavenge inder having exhaust ports formed in a circum- >
ing air ‘and the lower of said rows being for the ferential row below its top with an upward in
expulsion of exhaust gas, together witha valve chnation, a similarly formed upward and also
controlling the admission of scavenging air , tangentially disposed series of scavenging air ad55 through the ?rst named, row and allowing such ' mission ports above the level 01' the exhaust ports
admission only after the second named row has adapted to inject air streams into the combus
been opened to exhaust. by piston movement tion space with a helical swirling motion against
opening and closing both rows; the said upper the cylinder walls. toward its top, a top formed so
scavenging .air ports being terminals of nozzles as to reverse the‘ swirling movement of injected
60 extending through the walls'of the cylinder with air centrally downward through the space inside
inclination toward the combustion end thereof the entering streams to the lower exhaust port
and having a tangential component with relation > level, a piston formed with a conical top and
thereto. .
operating to open and close both the exhaust
3. An internal combustion engine cylinder hav
and air admission ports, and a valve controlling
ing a complete circumferential row‘of ports for said air admission ports to admit said air only
the admission of scavenging air, a juxtaposed when the exhaust ports ‘have begun to open by
complete circumferential row of exhaust ports the piston movement and to shut off said admis
more remote from'the combustion end ‘of the . sion only when said exhaust ports have been
cylinder than the ?rst-named row and a valve again closed by the piston.
controlling the air admission through said ?rst
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