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Патент USA US2409534

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Oct. 15, 1946.
D. M. BORDEN
2,409,533
APPARATUS FOR CONTROLLING SUPERCHARGERS
Filed Jan. 19, 1944
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INVENTOR
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Oct. 15, 1946.
D_ M_ éoRDEN
2,409,533
APPARATUS FOR CONTROLLING SUPERCHARGERS
Filed Jan. 19, 1944
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INVEN'I'OR
ATTORNEYS.
Patented Oct. 15, 1946
UNITED STATES PATENT OFFICE
2,409,533
APPARATUS FOR CONTROLLING
SUPEROHARGERS
David M. Borden, Royal Oak, Mich, assignor to
Chrysler Corporation, Highland Park, Mioh., a
corporation of Delaware
Application January 19, 1944, Serial No. 518,829
16 Claims.
(01. 230-115)
1
This application is a continuation-in-part of
copending application serial No. 480,786, filed
March 27, 1943, in the names of Henry S. Gil?llan,
David M. Borden and Paul W. Wyckolf. This
application relates broadly to a means employed
for keeping a supercharger within the pumping
limit. Broadly these means respond. to a condi
tion of operation in which pressure increase in
the supercharger becomes greater than a con
2
wherein the pilot, by manual settings of a control
lever, may approximate a satisfactory coordina
tion of the several variables, and wherein auto
matic mechanism, responsive to such variables
5 or changes therein, will be brought into action
to make such further adjustments as conditions
warrant.
In a general or comprehensive aspect, the in
vention looks forward to the simultaneous con
stant times the velocity head of the gas entering 10 trol of: the discharge pressure at the supercharger I
the supercharger. . The means shown in the Fig. 1
and its restrictions to values within those imposed
and grouped under D for carrying this out is ‘ by the pumping limit; the supercharger speed;
claimed speci?cally in the copending application
the engine speed and its ratio to the supercharger
of Henry W. Gil?llan, Serial No. 480,786, ?led
speed; and the richness of the fuel mixture sup
March 27, 1943. This means is claimed broadly 15 plied to the engine inlet manifold. As will be
in the present application. Also means for this
made to appear from the following portions of
same purpose shown in Figs. 3 to 6 is claimed in
this description andthe appended claims, nu
the present application.
merous sub-combinations of this control system
This invention relates to apparatus for control
may be employed to advantage without inclusion
ling the power plant in an aircraft, and it has 20 of other parts, while further controls may, if de
particular reference to a control system in which
sired, be superimposed on those herein speci?- '
a number of co-related functions governing the
operation of the power plant are subjected to an
integrated manual and automatic control.
cally considered.
,
‘
It Will have been observed that use has been
made of the term, “pumping limit.” When the
As herein employed, the term “power plant” 25 characteristic curve for a supercharger, operating
embraces the internal combustion engine proper,
at some designated speed, is plotted, it is readily
the propeller connected to the engine, and the
noticeable that a point is reached where further
supercharger which compresses the relatively rare
reductions in the quantity of air passing through
air for delivery with the fuel to the engine inlet
the machine fail to produce proportionate in
manifold. These units are often interconnected 30 creases in the di?erence between the delivery and
by gearing for simultaneous rotation. For satis
factory performance, it is necessaryto correlate
inlet pressures. This point is sometimes called
the surge point, and, with respect to axial ?ow
a number of variables, such as engine or propeller
compressors, its existence may be explained by
speed, the amount of fuel mixture and the pro
considering the character of flow through the
portions of air and fuel in such mixture deliv
supercharger. Too low a velocity of the air, with
ered to the engine, the actual speed of the super
respect to the rotational speed of the blades and
charger and its ratio to the engine speed, and
their formation, causes the air to meet the blades
the pressure at which the fuel mixture is sup
at too great an angle of attack, aerodynamic flow
plied. The wide variations in speed and power
is interrupted and the machine stalls. This con
loads on the engine, and the variations in the 40 dition produces noises and vibrations and pulsa
. air supply due to changes in density and tempera
tions which may cause physical failure of the
ture with changes in altitude, coupled with the
parts, with attendant disruption of the entire
incidents of ?ight service, make the integration
power plant. Accordingly, operation of. the su
and resolution of these variables an‘ extremely
percharger at or beyond the surge point is to be
difficult task. Independent manual adjustments,
made by the pilot or crew in response to indicating
dial readings, are too dependent on human frail
ties and precccupaticns to be satisfactory, espe
‘- avoided.
On the other hand, the supercharger has the
duty of supplying to the engine that quantity of
but otherwise as automatic in its reactions as
air, under suitable pressure, which is needed un
der its wide range of operating speeds and horse
power demands. Since the aircraft operates from
sea level to very high altitudes, it is apparent that
the density, and therefore the mass, of inducted
may be, is indicated.
‘air is also a variable.
The present invention contemplates such a
combined manual and automatic control system,
charger designed to supply enough low density
cially when the plane participates in aerial com
bat.
Accordingly, a coordinated control system, ‘
subject in some respects to the pilot’s supervision,
Presupposing a super
" air, compressed to a suitable pressure, for an open
2,409,533
3
4
throttle condition of the engine, then the same
denser air at the same speed, nor with the same
rare?ed air at a lower speed, since a change in
either of these factors may adversely affect the
details, since these, as such, form no part of the
present invention and are here unnecessary for
a full presentation of the subject to those skilled
in the art. For like reasons, no attempt has been
made to illustrate an airplane engine, nor the
angle of attack.
details of a supercharger, nor the mechanism
supercharger may not operate effectively with
interconnecting the same.
In approaching a consideration of the draw
charger, subjected to changes in these variables,
ings, it may be initially helpful to designate cer
are plotted, it is found that they lie in or along
another curve, which establishes the “pumping ll) tain of the units by reference letters, the details
of which will be presented hereinafter. The unit
limit” for the supercharger throughout the range
A is a rotary member manually operable by the
of operating conditions which it may encounter.
pilot into various positions and, the automatic
In practice, it means that a certain relationship
control features are, to a large extent, governed
must be maintained between the pressure rise
by the setting of this control instrumentality.
through the machine, and the ‘quantity of air
The unit B is a valve including member, man
which passes through the supercharger. Mathe
matically, the relationship may be expressed, with
ually operable by reason of its connection to the
unit A, and further subject to automatic adjust
su?icient accuracy for present purposes, by a
ment. The unit C is a valve device responsive
simple equation in this form:
When the surge points for the same super
20 to excess changes in the pressure conditions oc-
curring therein. The three units A, B, and C
operate conjunctively with a supply of hydraulic
pressure ?uid entering the units through a ?lter
F, and in such manner as to establish the posi
Where P2 is the pressure of the discharged air; P1
is the inlet or barometric pressure; p is the density
of the inducted air; 1) its velocity; and K, K’, are
constants.
tion of a waste gate or spill valve G positioned in
the supercharger delivery line. These units,
therefore, modulate the discharge pressure of the
supercharger, which is designated by the ref
In one aspect, this invention contemplates a
control system in which the supercharger is made
to operate within the pumping limit. The prin
ciples and means hereinafter discussed in detail‘
will disclose how such result is obtained.
erence letter S.
The unit D at the left of Fig. 1 is a pumping
limit detector whose function it is to supervise,
and even to overrule, the decisions made by the
foregoing units in connection with the setting of
the valve G. In other words, the detector D in
sures the operation of the supercharger S within
its pumping limit. The unit E, on the right hand
side of the control rotor A, is provided to govern
the speed ratio between the supercharger S and
the engine (not shown). With this unit is asso~
30
An object of the present invention is to provide
means for causing a supercharger to operate
within its pumping limit.
Among others, the present invention has as an
object the control and regulation of a spill valve
or waste g-ate connected to the supercharger de
livery line, so that the quantity and pressure of
the air may be maintained-at a suitable value.
Other objects include the provision of means to
govern the speed ratio between the supercharger 4.0 ciated a solenoid control valve H and electrical
and the engine; the speed of the engine in rela
circuits illustrated diagrammatically at the upper
tion to the torque demand of the propeller; and
right of the ?gure. The unit M is a mechanism
provided to adjust the fuel mixture and it is also
the supply of either a rich or lean fuel mixture
responsive to the setting of the rotor A. The
to the engine.
Further objects contemplate the devising of
" linkage L, also connected to the rotor A, is con
automatic mechanism and means for carrying
nected at its opposite end to the propeller gov
out the general objectives, including dampening
devices, and safety features, insuring the proper
the speed of the engine, as shown in Fig. 2.
ernor of the engine in such manner as to govern
functioning of the system.
Additional objects, and the advantages to be
derived from the practice of the invention, both
Supercharger discharge pressure regulation
Air enters the supercharger S through an inlet
line H, ?owing through a venturi l2 and thence
into the inlet of the supercharger for delivery
into a line l3 which is connected to the engine
inlet manifold at a point not shown. The line it
is provided with a lateral or spill pipe ill in which
is rotatably mounted the waste gate or spill valve
G. An open position of the valve G permits the
supercharger discharge to bleed to the at~
mosphere, a closed position of the valve G directs
in its entirety or by use of its several compo
nents, will become apparent from a perusal of the
following description of a preferred embodiment,
read in connection with the accompanying draw
ings.
In the drawings,
Fig. 1 shows, partially in sectional perspective
and partially in conventional diagram, a control
system embodying the principles of the inven
tion, and presently preferred mechanism for
all of the discharge to the engine manifold, and
intermediate positions of the valve permit pro
applying the same in practice;
Fig. 2 shows an airplane propeller and pitch
portionate withdrawals of the compressed air,
control therefor;
either to diminish its quantity or its pressure.
Fig. 3 shows diagrammatically a ?rst modified
form for establishing pumping limit control;
Fig. 4 shows diagrammatically a second modi
?ed form of the same;
Fig. 5 shows diagrammatically a third modi?ed
form of the same;
Fig. 6 shows diagrammatically a fourth modi
The system is such that the pilot may manually
position the gate G. For this purpose a link 15,
operable from the pilot’s position, is connected
by a clevis to a radial arm I6 extending from
the outer surface of the unit A. The unit A
-
comprises a pivotally mounted rotatable member
having a plurality of cams formed on its external
?ed form of the same.
periphery, and internally divided into two cham
For the purposes of clarity and simplicity, there
are omitted from the drawings representations
bers by means of inwardly extending sectors H
and i8.
These are cut away at the center to
of various standard parts, accessories, and design .75 receive a diametrically extending vane l9, ro
5
2,409,533
tatable within and with respect to the casing of
the rotor A. There are thus formed pairs of
opposed chambers 2| and 22, the chambers in
each pair being connected by holes 24 diagonally
drilled through the hub of the vane Id. The sev
eral chambers 2| and 22 are flooded with hydrau
lic pressure fluid admitted from a suitable source
6
which are in communication with the opposed
chambers 58 and 59. Each chamber also receives
a spring 6|. The chamber 58 is connected to the
chambers 2| of the unit A by the above mentioned
piping 25, while the chambers 22 are connected
to the chamber 59 by the piping 25. Since, as
previously noted, ports 53 and Eli of the unit B are
normally blocked by the valve discs #33 and 44, it
through the oil ?lter F and normally blocked
off from free flow by valve mechanism herein~
will now be apparent why there can be no dis
after described. Admission or withdrawal of the 10 placement of the pressure ?uid in the chambers
pressure ?uid to the‘ chambers is effected by
2| and 22, and why the vane IS must, under
piping 25 and 26 entering the pairs of chambers
these conditions, turn with the unit A.
through ducts formed in the rotor casing wall.
However, while initial rotation of the manu
The vane l9 is, of course, rotatably pivoted for
ally operable rotor A causes the valve G to shift,
motion relative to the rotor casing, and the unit
due to the drag on the vane iii, rotation of the
as illustrated is also provided with a cover plate
unit A (in a counterclockwise direction, for ex
in order to close the chambers and preclude oil
ample) also draws the longitudinally movable
leakage.
sleeve 36 to the right, due to the intermeshing of
It will be observed that, with the parts in the
the segment 2% with the rack 29. This motion
position illustrated, a left hand movement of the 20 connects the port 53 with the port 42, and the
link l5 will effect a counterclockwise rotation of
port 54 with the port til. Accordingly, pressure
the rotor A. Since it has been assumed that
?uid may now ?ow through the line 4|, ports
the chambers 2| and 22 are blocked against
42 and E3, chamber 59, and line 25, to the pair of
flow of oil, then such movement will drag the
chambers 22. The chambers 2| are concurrently
vane l9 also in a counterclockwise direction to
connected to the drain line 52 through the piping
rotate an attached shaft 21 upon which is
25, chamber 58, ports 54 and Ill, and lateral 5|.
mounted the gate valve G. Counterlockwise rc
Hydraulic pressure is now applied through the
tation of the valve will close the lateral M, and
chambers 22 to cause the vane id to move in a
thereby operate to build up rapidly the pressure
counterclockwise direction to its limiting position,
in the engine inlet line I3. Conversely, clockwise
or, the movement of the rotor A brings into play
rotation of the unit A would, under the same
mechanism causing the rotor l9 to overtravel.
blocked condition for the vane l9, open the valve
Conversely, if the rotor A were rotated in a
G to its limiting position. A gear segment 28
clockwise direction, as by pulling the link l5 to
is formed on the lower external portion of the
the right, then the sleeve 34 would be shifted to
rotor A and its teeth engage with a rack 29 in
the left. The flow into and away from the rotor
cluded in the unit B.
would now be reversed, admission being effected
This unit‘ comprises a stationary cylindrical
through the ports 132 and M, and discharge oc
housing 3| (note, for example, the Securing lugs
curring through the ports 53 and 45. The re
32 at the extreme right). The cylinder 3| is
mainder of the circuits is the same as heretofore
suitably cut away at its mid portion to permit 40 noted. Too rapid overtravel of the vane IS in
engagement of the teeth of the gear and rack 28
either rotational direction is forestalled, however,
and 29, while the right hand portion 33 is en
by the operation of the stabilizing unit C. A
larged. ‘Within the bore of the cylinder 3! is a
rapid increase in pressure in either chamber 58
longitudinally movable sleeve 34 having on its
or 59;, coupled with a sudden release of hydraulic
external surface the rack 29. The sleeve 34 in 45 pressure in the‘opposite chamber, creates mo
turn receives a valve unit 35 provided with a stem
mentarily a substantial pressure differential on
36 which extends to the right hand section 33
the opposite ends of the piston 51. This pressure
vwhere it is coupled with a bellows assembly in~
differential, therefore, drives the piston into one
cluding the bellows 3? and 38. The left hand
chamber or the other, to close, by means of abut
section of the sliding sleeve 34 is provided with 50 ting valve discs 52, one or the other of the con—
ports and fluid pressure line connections adapted
nections to the ports 53 or 543. Accordingly, the
to be opened or closed by relative movement of
outwardly ?owing oil develops a back pressure in
the valve 35.
the discharging chambers 2| or 22, and in this
Pressure fluid is admitted to the unit B through
way prevents the vane iii from going to its ex
a pressure line 4| into an inlet chamber 42 con 55 treme position too rapidly. Obviously, the action
nected to the clear space between the valve discs
of the piston 51 is the same, except for its direc
43 and“. Similar ports 45 and Ill are provided
tion of motion, irrespective of the application of
for normal connection to the space between discs
the hydraulic pressure to either side of the vane
43 and 48 and 44 and t9 respectively. These last
member | 9. Accordingly, the valve G will initiah
mentioned ports are coupled together by tubes 5|
1y move to that position determined by the man
which in turn are connected to a drain line 52.
The sleeve 34 is also provided, at a radially remote
ual setting of the control unit A and will there
after tend to creep forward to its limiting po
region, with two additional ports 53 and 54. These
sition.
ports are normally covered by the valve discs it
Opposition to overtravel, and restoration of the
and M. Thus, in the position shown, pressure 65 valve G to a suitable position, is effected through
?uid may enter the region between the discs 43
the bellows assembly contained in the right hand
and 44 via the port £32, but it cannot go anywhere
section 33 of the unit B. The bellows 38 is se
because the exit ports 53 and 5d are blocked by
these discs.
_
cured at one end to the Wall 65, and, at its op
posite end, it is joined to the bellows 31, being
The ports 53 and 54 are connected by suitable 70 sealed therefrom by the disc 55. Before sealing,
tubing to oppose chambers formed within the eas
the bellows 38 is evacuated to a very low or nega
ing of the unit C. ‘This casing has a central
tive gauge pressure. The bellows 3'5, which is free
- shoulder portion 56 receiving a piston 57 which is
to ?oat in the casing 33, is connected at its op
normally maintained in its centralized position
posits end to the valve stem 36, and it is also
by the hydraulic pressure exerted on its ends, 75 provided with a vent 61 of small diameter. The
2,409,533
7
space between the bellows and the inner wall of
the, casing 33 is connected to the supercharger
discharge line 43 by a conduit 68. An end wall
69, positioned between the casing 33 and the
sleeve 34, and formed with a suitable gland to
receive the stem 35, prevents manifold pressure
from being exerted on the valve disc 49.
Increase in the manifold pressure, caused by
closing the gate G, therefore causes an increased
pressure to be exerted on the sealed bellows 38,
to contract its length. This movement draws the
valve stem 36 to the right, and therefore replaces
the discs 43 and All over the ports 53 and 55.
Flow of the hydraulic ?uid is accordingly ar
rested, and the valve G is ?xed in position. Con
versely, had the rotor A been turned to open the
gate G, then the sleeve 35 would have been shift
ed to the left, and the diminution of manifold
pressure would have permitted the bellows 33 to
expand. The valve discs 43 and 44 would again
have followed after the ports 53 and 54 to restore
and maintain the balanced condition.
It is apparent that any condition causing a
change in the manifold pressure is re?ected by
the extension or contraction of the bellows 33,
with compatible readjustments of the valve mech~
anism in the unit B, and the positioning of the
gate G. Regulation of the manifold discharge
pressure, and its maintenance at a substantially
constant value, is thereby effected.
Such regulation is not, however, necessarily
instantaneous, because of the action of the bel
lows 3?. Since both interior and exterior of this
bellows are normally subjected to equal pressures,
by reason of the vent 5i, relatively slow or small
changes in manifold pressure have no signi?cant
effect on the bellows 37. When rapid pressure
changes tend to occur, as for example, during a
power dive or steep climb, the rapid change in
the pressure on the exterior of the bellows Bl
creates a pressure differential, due to the re
stricting effect of the ori?ce El. The bellows 31
will then tend to expand or collapse, as the case
may be, and thereby add to or subtract from the
force acting on the valve stem 35.
It will be noted that the bellows 31, which is
sensitive to the rate of change of manifold pres
sure, effects a rapid adjustment of the valve unit
35 in anticipating the adjustments to be secured
by the bellows 38.
Thus, in a power dive, the
manifold pressure increases, because of the rapid
transfer to a region of denser air. The pressure
different diameters, and a central bore 14. The
chamber 12 is divided into two parts by a dia
phragm 75, the left hand part being connected to
inlet pressure by a pipe 16 leading to the super
charger inlet II. The right hand part is con
nected by a pipe Tl to the venturi 12. The dia
phragm ‘i5 is, therefore, subject to an unbalanced
pressure proportionate to the pressure drop
between the upstream and throat regions of the
10 venturi, which pressure tends to force the
diaphragm 15 to the right.
The right hand chamber T3 is divided into
three sections by two spaced diaphragms ‘Ila and
T8. The middle chamber, between the two dia
15 phragms, is subjected to inlet pressure by a con
duit 19 leading to the pipe 75. The right hand
section of the chamber ‘i3 is connected to the
supercharger discharge line l3 by a pipe Bl, and
to the left hand section by a duct 82. Thus, the
20 same high pressure is applied in opposing direc
tlons of the diaphragms Na and 18 against the
relatively low resistance of inlet pressure in the
space between the‘ diaphragms.
The area of the diaphragm i8 is greater than
that of the diaphragm ‘Ha, but less than that of
the left hand diaphragm 15. There is thus a
resulting force which tends to push the dia
phragms ‘Fla and 18 toward the left. Interposed
between the two chambers 12 and 13, and in the
bore ‘15, is a valve unit whose stem 85 abuts both
the diaphragrns ‘l5 and Ila. A centrally located
valve disc 85 normally uncovers a port 86, which
is connected to high pressure hydraulic ?uid by a
branch 8?. The liquid is thus admitted to the
clear space between the disc 85 and another disc
88, which space is connected to the pressure line
4! by a port 89. The previously described drain
line 52 is coupled to a port 9! leading to the clear
space between the disc 85 and a third disc 92,
for connection to a port 53 in communication
with the master drain line 95. Another drain line
95 leads through an additional port 96 to the
clear space between the discs 85 and 88, to be
come effective when the valve assembly is pushed
over to the left. At that time, the inlet line 81
45 is coupled to the line 52, while the master drain is
connected to the line 5!.
'
Any shifting of the valve stem at which makes
the line Ill a drain, and the line 52 a pressure
supply line, of course completely reverses the
direction of application offorce on the vane H!
of unit A, as heretofore described. In other
words, the valve settings of unit D, under the
increase operates to foreshorten the bellows 31,
normally
existing pressure condition, make the
thus admitting pressure fluid through port 54 to
line ill a pressure line, whereby the units A, B
chambers H, to open the spill valve G, as previ 55 and C regulate the setting of the gate G as for
ously described. As the pressures within and
merly stated. When the settings are reversed,
outside of the bellows 3? become equalized, by
then the vane l9, instead of moving the gate G
?ow through the ori?ce 67, the bellows expands.
to a closed position, for example, will move it to
In fact, due to the falling external pressure,
an open position. The detector D may there
caused by the opening of gate G, the bellows may 60 fore completely nullify the natural inclination
actually be extended beyond its free length. By
of the units A, B and C in actuating the valve
this time, however, the bellows 38 has taken a
G, and therefore, the supercharger discharge
new position 'to govern the setting of the gate,
pressure.
and the combined assembly therefore works to
The detector operates to overrule the waste
meet a rapid pressure change with a rapid read
gate regulator, and reverse its action, when the
justment, followed by rapid dampening to prevent
amount of delivered air is so small, with respect
hunting of the valve 35.
to the pressure rise, that the pumping limit of
Pumping‘ limit detector
the supercharger is reached. Such a situation
may arise under variation in the controlling fac
The pumping limit detector D is provided to
tors heretofore discussed.
supervise the performance of the units A, B and
Referring again to the left hand chamber 12
C, as just described, and it will be herein treated
insofar as it forms an element of the combina
of the unit I), it will be seen that the force ex
erted in the right hand direction, which tends to
tions constituting a part of this invention.
keep the main pressure line in communication
The unit D comprises a cylindrical ‘ll provided
with left and right hand chambers 12. and 13 of 75 with the line 4|, is: proportional to the working
2,409,533
area of the diaphragm ‘I5 and to the pressure
drop from atmosphere to the Venturi throat I2.
10
adequate quantity of air and still operate safely
within the pumping limit. The particular drive
just referred to is not the subject matter of this
invention, and therefore, is not shown in detail.
the mean effective thrust on the left hand end'of 5 Here, the description is concerned with the con
the valve stem 84 may be proportioned to the ex
trol of the drive, and, since a fluid coupling is
pression: [p02]. The left hand thrust is similarly
involved, the control means‘ is made to govern
proportioned to the pressure rise (P2—P1), since
the supply of hydraulic ?uid to the coupling.
the middle section of chamber ‘I3 is connected to
There are'two hydraulic pressure ?uid lines,
atmosphere, while the other faces of the differenj 10 II3, I I4, which lead from the unit H to the cou
tial diaphragrns ‘Ila and ‘I8 are subjected to the
pling l I2, and a main feeder I I5 extends from the
supercharger discharge pressure.
?lter F to the unit H. When the feeder H5 is
Accordingly, under normal conditions of oper
connected to the line H3, the unit H2 is in low
ation, or over that range of pressure quantity
speed, and, when the unit is actuated to couple
ratios within the pumping limit, the detector D 15 the lines H5 and M4, the supercharger S is
permits admission of the hydraulic‘ pressure fluid
driven through the high speed ratio. Selection of
to the line Ill. The units A, B and C then func
the position of the unit H may be effected either
tion as first described, the manifold pressure is
manually, or automatically through the unit E.
regulated, and any excess air delivered at that
The unit E comprises a ?xed cylindrical casing
pressure, which is not needed by the engine, 20 I2I having a movable follower I22 projecting
passes to waste through the partially open spill
from one end thereof, and held in engagement
valve G. When this relationship changes in such
with a cam I23 on the rotor unit A by means of
manner as to cause the supercharger S to ap
a spring I24, disposed in the casing I2I between
proach its pumping limit, the gate G, rather than
its end wall and the inner end of the follower.
being turned to a closed position in the manner
A sealed bellows I25 is ?xed to the free end of
?rst outlined, will now be thrust toward an open
the follower I22, and it abuts a push pin I26‘ of
position. The resulting reduction of discharge
an electric switch I27. The follower I22 is open
pressure head, by the relief of the compressed
to the atmosphere, and the bellows I25‘ is evacu
air, is re?ected in the line 8i and on the dia
ated. Hence, atmospheric pressure tends to
phragms lid and ‘I8, as well as the bellows 37
collapse the bellows and withdraw its inner end
and 38. Valve stem 84 may then move toward
from engagement with the push pin I26. At
the right, restoring to line H its function as a
higher altitudes the bellows will expand, due to
The pressure drop is in turn proportional to the
mass, density of the air, and its velocity. Hence,
pressure ?uid supply line, and thereby making
the lower air density, and may do so even to a
the unit B once more the control instrumentality.
point where it can press the pin I26 su?iciently
hard to snap the switch I2'I, everything else dis
It will have been noted that the right hand face
of the .diaphragm ‘It’ carries an evacuated bellows
9i, which subtracts from the working area on
regarded. Normally, the parts are so propor
tioned that, at sea level, the maximum lift of
the cam I23, brought into play by rotation of unit
A, is insu?icient to offset the contraction of the
that side, thereby making the unit D more sensi
tive and accurate in its operation.
It may be assumed that operation of the air 40 bellows , I25. As higher altitudes are reached,
craft causing the detector D to cut in and out of
extension of the bellows I25 permits the actua
service will be accompanied by other conditions
observed by the pilot. He may then elect to
shift the link IE to the extreme right, thereby to
tion of the pin I26 at di?erent settings of the
cam I23, until ?nally a point is reached where
actuation of the rotor A becomes unnecessary,
open the gate G, manually, and he may more 4-5 as just pointed out. Thus, the switch I21 will
over desire to throttle the engine to an even
snap at some predetermined altitude, established
greater extent. For this purpose, the arm It,
by the setting of the rotor A and the barometric
connected to the link I5, is provided with a pin
pressure. 0r, stated otherwise, each setting of
IIII, to which is attached a rod I02 formed with
the rotor A, by the manual lever I5, determines
a terminal slot I03. The slot receives a pin I84
the altitude at which the supercharger may go
into high speed.
~
'
connected to a linkage I25, which is connected
in turn to a damper Illt pivoted in the manifold
The switch I27, as shown in the diagrammatic
line I 3. Normal back and forth motion of the
‘repetition in the drawings, is of a single pole,
rod I92 simply causes the pin IM to ride in the
double throw type, wherein inward movement of
slot I 63. Under these conditions the damper I08 55 the pin I26 forces the resiliently supported lever
hangs wide open, and is not affected at all. How
I28 into engagement with a high speed contact
ever, if the link I5 is pulled to its extreme posi
I29, while withdrawal of the pin I26 permits the
tion, the end of the slot Hi3 engages the pin IM,
lever £28 to move forward against a low speed
pulling it along to close the damper I36, and
contact I31. Manual control over the electrical
thereby additionally throttle the engine. Res 60 circuit is obtained through a switch having a
toration of the link It to a normal operating
pivoted arm I33 which may be selectively set on
range permits the damper to open, restoring the
an automatic control contact I34, a low speed
control of the air supply to the unitsheretofore
contact I35, or a high speed contact I36. When
considered.
‘
the arm is in the position shown, the gearing II2
Supercharger drive control
(i5 may be in either high or low ratio; when point
I35 is used only a low ratio is available, and when
The supercharger S is driven from the engine
point I 36 is connected, the high speed‘ratio is
through a drive unit H2, which, as herein indi
selected, subject to certain limitations hereafter
cated includes ?uid coupling members and gear
stated.
ing permitting the supercharger to run at one or 70 ‘ The circuits established by the settings of
the other of two speed ratios. Normally, the
switches I33 and I2‘! (which will be traced di
gearing will be set to drive in the low speed ratio.
rectly) determine whether fluid will flow from
However, when high altitudes are encountered,
line H5, through unit H, to line H3 or line H4.
\ it may be necessary to shift to the higher speed
This unit comprises a housing I31 formed with
ratio, so that the supercharger may deliver an
abore I33 in which is slidably mounted a valve
-
l1
.
7
member I36. The feeder line H5 connects to a
port I4I, communicating with the bore I38, while
12
I16 to wire I15 into the armature I16 of a relay R,
then engaging contact I11 connected to wire I18
leading to contact I61 on stem I5I; thence
through disc I64 to contact I66 and wire I'II to
the winding of the solenoid I63, to ground and
The valve member carries a series of spaced
return. Plunger IE2 is thereupon lifted to pull
discs which serve to direct pressure fluid to the
down the valve I36 as previously described, the
line II3 or H4, depending upon their relation
disc I65;- being separated from contacts I66 and
to the port I 4|. The structure is so similar to
I61 to break the circuit just traced when the
the valves heretofore described that it is believed
links I6I aproach dead center. The disc I65 will
unnecessary to elaborate thereon. It may, how
accordingly engage contacts I66 and I66 when
ever, be noted that the unit is formed with addi
the parts have come to rest.
tional similar ports I45 which seem to re-open
When the pin I26 is withdrawn, switch arm
the feeder I I5 to the line from which it otherwise
I26 engages low speed contact I3I, and a re
would be blocked. This, however, is desirable,
since the short-circuiting connection is taken 15 versal of the fluid connections, to restore the low
speed ratio, is eifected through the following
through a restricted ori?ce, as shown. Admis
circuit: From the power source to contact I3I,
sion of a limited amount of fluid to the blocked
wire I16, junction I6I, wires I82 and I83, thence
line I I3 or II4 assures lubrication and cooling of
through disc I65 and contacts I68 and I69 to
the coupling then out of service, but the total
the solenoid I63.
?ow is too small for power transmission
Let it be assumed that the pilot selects the low
purposes.
’
speed contact I35 for the switch arm I33. Cur
The valve member I39 has an extended stem
rent then flows through contact I35 and wire I83
I5I terminating in‘a clevis I52, the pin of which
to contact I66, thereby to establish a circuit for
is positioned in a slot I53 of a lever I54, pivoted
on a fulcrum I65. The opposite arm of the lever 25 low speed position of the unit 1-1. If it be assumed
that the high speed contact I36 is selected, the
is formed with a fork I56, in which may ride a
solenoid valve unit will (subject to a subsequently
pin I51 extending from a rocker segment I68.
stated limitation) remain in the desired position,
The segment, which is centrally pivoted on a
being actuated through the following circuit:
stud’ I 59, carries a pair of links I6I at one corner,
which extend to a plunger I62 of a solenoid I63. ; Contact I36, wire I15, armature I16 and contact
I11 of relay R, thence via wire I18 to contact
When the solenoid is energized, the plunger is
pulled up, thereby to rotate the segment I53 into
I61, etc.
The relay R, is introduced into the high speed
a substantially vertical position. As will presently
circuit to enforce a low speed gearing when the
appear, such movement simultaneously breaks
compressed air in the delivery line I3 exceeds a
.the energizing circuit, permitting the plunger I62
predetermined temperature. The relay includes
to drop away. Due to the inertia of the moving
a coil I85, connected directly to the power source
parts, however, the segment does not fall back to
by a wire I66 and a wire I81 leading through a
its starting position, but continues its travel to the
thermostatic switch I68 positioned in the pipe I3.
opposite upper quadrant from which it started.
Thus, each energization of the solenoid shifts the LIL D Thus, the coil I85 will be energized whenever
switch I86 closes at a predetermined temperature.
pin I51 up or down.
Armature I16 is then pulled down against the
This motion is transmitted through the lever
urge of its holding spring I86 to engage contact
I54 to shift the valve stem I5I either down or up,
I6I, which leads via wire E92 to junction IBI, and
as the case may be. For example, the drawings
so into the low speed selecting circuit.
show the links I6I in the second quadrant and
The armature I16 is latched into this position
the valve discs I44 so located as to supply pressure
by an armature I93 of a second coil I94, which
?uid to'the low speed line II3. Upon energizing
‘must be energized to permit the armature I16 to
the solenoid I63, links l6I swing to the ?rst
return into engagement with contact I11, after
quadrant, and stem I5I is pulled down to connect
ports I4! and I63, thereby supplying high speed 50 the switch I66 has opened. A circuit for this coil
is established by contacts I65 and I96, connected
line I I6, and blocking line II3 except for the
to the coil, and adapted to be bridged by a manu_
reduced lubricating flow alluded to. On the next
ally depressible switch arm I67.
vene'rgization, the motion is reversed and the stem
It will thus be seen that the control of the
I5I is pushed up to restore it to the position
illustrated
55 supercharger speed ratio is quite flexible, the
the lines I I3 and I I4 are respectively connected to
‘axially spaced ports I42 and I63.
,The stem I6I carries spaced conductive discs
pilot may insist on a low ratio, or a high ratio
I64 and I65, which respectively bridge either con
tacts I66 and I61 or contacts I68 and I69, de
pending upon the position of the valve. Con
tacts I66 and I68 are connected by a common
wire [TI to the solenoid I63, the other side of
subject to the thermostatic supervision; or he
may let the ratio be determined automatically but
still subject to his positioning of the rotor A.
which is grounded.
_
Let it be asumed that the machine has been
running in the lower speed ratio, the parts of the
solenoid valve unit H being as shown, and that
the pin I26 has just been moved to force the
switch arm I28 into engagement with the high
speed contact I29, the switch arm I133 then
contacting the automatic control point I34. A
Engine regulation
The engine of the power plant is supplied with
air flowing past the damper I66, and fuel which
is later mixed with such air.
It is common in
the art to include, with the engine, a proportion
ing device through which the relative percentages
of fuel and air are determined and maintained.
However, it is desirable to supervise the perform
ance of such device in response to the manifold
pressure, as determined by the instrumentalities
0.
heretofore considered. Thus, if the manifold
to shift the valve member I39, is now established
pressure becomes either high-or low, a rich mix
‘ as follows:
ture is indicated, while at intermediate pressures,
'From the power source through arm I33, con
the mixture may be lean.
‘,‘tact I34, wire I12 to arm I23 and high speed
contact I29, thence via wire I13 and junction 75 Means for assuring the rich mixture are pro
circuit for energizing the solenoid I63, thereby
13
2,409,533
la
vided by the unit M, operating in conjunction
pendent adjustments. He is, however, free to
with the manifold control unit A. The unit M
comprises a valve casing 28! enclosing a spring
supervise many such adjustments by his over
riding‘manual controls, and he may therefore
exercise his judgment with considerable latitude.
The system is obviously directed to one wherein
loaded ‘piston 262, whose stem 203 extends be
yond the casing for connection to the carburetor
controls, not shown.
the superchargeris regulated by control of the
The casing 20! also contains a bore 204 receiv
discharge pressure, rather than by throttling the
ing a plunger 205, formed with a stem 2% which
‘supercharger inlet, and any excess of air deliv
normally engages the dwell portion between two
ered at the predetermined pressure is accordingly
similar cams 26? on the rotor A. The bore 204 is 10 sent to waste. Such plan of control admits of
formed with ports on either side of the plunger
the simultaneous governing of the other related
225, one of which is connected by a pipe 268 to
variables, as hereinabove explained.
the main hydraulic feeder line H5. The other
Supplemental disclosure on pumping limit control
port is connected to a drain line, and it also com
municates with the upper side of the piston 202 15
The equation P2~—P1=K1/2pv2+K’P2, set forth
through a duct 209. Hydraulic pressure there
on page 2 is derived from the equation:
fore urges the plunger 205 to the right, bringing
the stem 2% into engagement with the periphery
of the unit A.
The plunger 205 normally partially uncovers a
in which K" and K’” are constants, Q is the
quantity of air in volume per unit of time sup
port 2!! below the piston 222, thereby enabling
pressure?uid from the line'2il3 to urge the pis
plied to the supercharger, T1 is the absolute tem
ton and its stem 283 upward. This position, by
perature of the entering air, P2 is the pressure of
connection to any suitable linkage, sets the can
the air discharged from the supercharger, and
buretor for operation in the usual manner. If, 25 P1 is the pressure of the entering air. I have
however, the rotor A is moved to either extreme
discovered that, if a curve is plotted of P2/P1
position, the stem 226 rides up on one or the
other of the cams 251i, and moves to the left to
against Q/\/T1 for pumping limit conditions, the
last mentioned equation will approximately de
block the line 208, and connect the port 2! I to
drainage. This permits the piston 282 to drop. 30
If the rotor A is rapidly shifted from one extreme
?ne this curve.
The ?rst mentioned equation may also be re
duced to a second form: P2-P1=KIVpv2-l-KVP1,
position to the other, the piston 222 will not, how
in which KW and KV are constants.
ever, be signi?cantly affected. This is due to the
Some claims are based on the ?rst equation and
fact that the admission of pressure ?uid through
so refer to P2 or the pressure of the gas delivered
the port MI is slow, in comparison to the drain 35 by the supercharger. Other claims are based on
age rate. Accordingly, the valve unit protects
the second equation and so refer to P1 or the pres
against sudden mixture changes which might be
sure of the gas received by the supercharger.
conducive to creating back?res. When the pis
' For some conditions this curve can be expressed
ton 2B2 drops, the corresponding movement of
by the equation:
the stem 263 sets the carburetor unit in such 40
position that only a rich fuel mixture can be sup
plied.
Since the extreme movement of unit A
corresponds to a high or low manifold pressure,
the apparatus therefore achieves the purpose in
tended.
Under take-off conditions, a relatively high
propeller, and engine, speed are desirable, while
under ?ight conditions it may be better to de
crease the speed. This can be done by changing
the propeller pitch.
The unit L is therefore provided to adjust the
propeller and engine speeds in response to the
manifold pressure. The periphery of the rotor of
unit A is formed with a milled cam slot 2I5, to
which is connected a bellcrank lever ZIE, the
upper arm of which is pivoted to a link 2 IT. This
Q
P2/ P1 ——l=KVI(—~_)
_\/T1
in which KVI is a constant.
2
This equation will
provide the equation: P2—-P1=KV"1/2pV2, in which
KVII is a constant.
.
-
For the pumping-limit control D of Fig. 1 the
equation: P2—-P1—_,~K 1/2pV2-|-K1P2 is applicable for
the exhausted bellows provides the correction des
ignated by K'P2.
In Fig. 2, there are shown a supercharger 2l8,
an intake line He, an outlet line 220, a line 221
leading to an engine, not shown, line 222 joined
to lines 225 and 22!, and a spill valve 223 in the
line 222. A Pitot tube 224 mounted in the inlet
“ line 219 is connected by a pipe 225 with a cylinder
226, in which is mounted a piston 221. A pipe
228 is connected to the pipe 225 and to a cylinder
propeller governor speed control, the propeller
229, in which is mounted a piston 23!). The
being indicated by 2 I 9. Hence, an extreme move
cylinder 229 is connected with a pipe 23!, in turn
ment of the rotor A, representing a high or low 60 connected with intake line 2 l 9. A connecting rod
manifold pressure, will affect the propeller pitch,
232 attached to piston 23!] is connected to one
link extends to a control mechanism 2H! for a
while in intermediate positions the inner end of ‘
the lever H6 is free to ride in the slot. H5. The
slot M5 is advantageously so cut as to insure a
de?nite relationship between engine speed and, .
manifold pressure-the curve being laid out from
knowledge of the engine characteristics. In such
case, intermediate settings of the rotor A cause
the lever ZIE to be positioned so as to follow the
end of a lever 233 having a fulcrum 234 at a mid
point. The other end of the lever 234 is con
nected to a connecting rod 235 attached to the
piston 221. The lever 233 is connected with the
spill valve 223 through a link 23% and a crank 23'!
?xed to the spill valve 223. The cylinder 226 is
connected by a pipe 238 with a Pitot tube 239 in
discharge line 222. The resultant force on the
speed and pressure relationship.
70 piston 22'! is the difference between the pressures
It will thus be seen that the present invention
in the pipes 225 and 238, or the difference in
provides an integrated control, automatic in
pressures between the Pitot tubes 224 and 239.
operation, for the various I components of the
- power plant, and accordingly relieves the pilot of
the necessity of making a large number of inde
Pitot tube 224 measures the total pressure in the
inlet line 219 or P1+1/gP1Vl2, (Pipi, and Vrbeing,
respectively, pressure, mass density, and velocity
2,409,533
15
of airor gas in ‘the inlet line 2 l 9). Pitot tube 239
measures the total pressure in the discharge line
228 or P2+1/2p2V22, (P2412, and V2 being, respec
tively, pressure, mass density, and velocity of air
or gas in the discharge 1ine‘22il). The difference
between these quantities is AP or the increase
in pressure from inlet 2&9 to discharge 220 and
is manifested in an upward thrust on piston 221.
The resultant force on piston ‘238 is proportional
to the di?erence in total pressures in the Pitot
15
connected at one side to the lever 233 by a link
241 and at the other side by a link 24-9 to the
crank 23"! secured to the spill valve 223. The
purpose .of the servo-motor is to ,multiply the
force AP—K1/2p1l/'12 sufliciently to enable it to
open the valve. The servo-motor may take any
suitable form.
While the invention has been described with
reference to one embodiment only, it will be ap
parent that numerous changes and modi?cations
may be made without departure from the princi
ples, or the scope of the following claims.
'I claim:
1. The combination with a supercharger adapt
tube 224 and the pipe 23!, since these parts are
connected to opposite ends of the cylinder 229.
The Pitot tube 224 is subjected to P1+1/2p1V12, and
the pipe 23!, simply to P1. The difference be
tween these quantities is 1/2p1'V12, which is mani 15 ed to receive gas at one pressure and to deliver
fested as an upward thrust on piston 230.
The
it at another greater pressure; of means for pre
venting the supercharger from exceeding the
forces AP and l/gplvlz act in opposition to one
pumping limit, said means comprising means
another because of the pistons 221 and 230
responsive to the velocity of the gas received by
through the connecting rods 235 and 232 to op
the supercharger, means responsive to increase
posite ends of the lever 233, The diameters of
in gas pressure effected by the supercharger, and
the pistons 22? and the piston 230 are so propor
means responsive to absolute pressure of the gas
tioned, and the fulcrum 234 is so positioned be
received by the supercharger, the three last men
tween the ends of the lever 233 that the effective
tioned means cooperating with one another to
thrust of l/epivi2 is magni?ed by a constant K de
pendent upon the characteristics of the super 25 prevent exceeding of the pumping limit upon
arising of a condition in which the increase in
charger. The force tending to hold the spill valve
gas pressure is in a neighborhood of value equal
223 closed is proportioned to K1/2p1V12—AP, and
to constant times the square of the velocity of
the valve is open when AP becomes greater than
the gas received by the supercharger plus a con
K1/2p1V12. Thus measurement of the pumping
limit of the supercharger 2l8 is based on the 30 stant times the absolute pressure of the gas re
equation AP=K1/2p1V12.
In the construction of Fig. 4 piston .230 in
cylinder 229 is subjected to an upward thrust
ceived by the supercharger. ’
2. The combination with a supercharger adapt
ed to receive gas at one pressure and to deliver
it at another greater pressure; of means for
equal to 1/2p1V12, since the lower end of cylinder
229 is connected to pipe 2M], connected in turn 35 preventing the supercharger from exceeding the
pumping limit, said means comprising means re
to Pitot tube 22G, subjected to P1+1/2p1V12, and
sponsive to the velocity and density of the gas
the upper end of cylinder is connected to pipe
received by the supercharger, means responsive
23f subjected to ‘P1. However, piston 22'! in
to increase in gas pressure eiTected by the super
cylinder 226 is subjected to a net upward thrust
only approximately equal to AP, since the upper 40 charger, and means responsive to absolute pres
sure of the gas received by the supercharger, the
and lower ends of the cylinder 226 are connected
to pipes 2M and 2H2, connected, respectively, to
three last mentioned means cooperating with one
‘inlet line 2H! through pipe 23l and to discharge
line 228 and subjected only to static pressures
limit upon arising of a condition in which the
another to prevent exceeding oi‘ the pumping
P1 and P2. However, the difference between P1 - f increase in gas pressure is in a neighborhood of
value equal to a constant times the square of
and P2 gives a su?iciently accurate AP. As in
the velocity of the gas received by the super
Fig. 3, the spill valve 223 of Fig. 3 opens when
AP becomes greater than'K1/2P1V12. For'Fig. 4
the measurement of the pumping limit is based
on the equation AP=K1/2p1V12.
charger times the density of the gas received plus
a constant times the absolute pressure of the gas
received by the supercharger.
3. The combination with a supercharger adapt
ed to receive gas at one pressure and to deliver
is substituted for tl pitot tube 224 of Figs. 3
it at another greater pressure; of means for
and 4 and is connected with the upper end .of
reducing the pressure of the delivered gas to keep
cylinder 22$‘. by pipe 244.. The lower end of 0371
inder 229 is connected with intake line 2!!! by 55 the supercharger within the pumping limit, said
means being responsive to arising of a condition
pipes 254 and 265. As in Figsii and 4, the net
in which the increase in gas pressure effected by
upward thrust on piston 230 in Fig. 5 is l/gplvlz.
the supercharger is in a neighborhood of value
The net upward thrust on position 22'! is the dif
equal to a constant times the square of the ve~
ference between static pressurePi in inlet line
2479, communicated to the upper end of the .cyl 60 locity of the gas received by the supercharger
plus a constant times the absolute pressure of
inder 226 by pipe 2115, and static pressure P2 in
the gas received by the supercharger.
discharge line 22!], --communicated through pipe
4. The combination with a supercharger adapt
.242. As in the construction of Fig. 41., the riPrep
ed to receive gas at one pressure and to deliver
resented by this diiference in static pressures P1
and P2 is only approximately equal .to the true 65 it at another greater pressure; of means for re
ducing the pressure ‘of the delivered gas to keep
pressure difference, but it is su?iciently accurate
the supercharger within the pumping limit, said
‘for the purposes of this application. As inFigs.
means being responsive to arising of a condition
3 and .4, the valve 223 of Fig. 5 opens when AP
in which the increase ingas pressure effected by
becomes greater than K‘/2p1V12. For Fig. 5 the
‘measurement of the pumping limit is based on 70 the supercharger is in a neighborhood of value
In the construction of Fig. 5 a Venturi tube 2/13
the equation AP=K1/2p1V12.
equal to a constant times the square of the ve
The construction vof Fig. 6 is similar to that of
(Fig. except that a servo-motor or servo-mech
anism 268 is introduced between the llever 1233
and the spill valve 223. The servo-motor 2.48 is 75
times the density of the gas received plus a con
stant times the absolute pressure of the gas re
locity of the gas received by the supercharger
ceived by the supercharger.
2,409,533
17
18
5. The combination with a supercharger adapt
connected with the outlet line, a ?rst cylinder, a
?rst piston mounted therein, a second cylinder,
ed to receive gas at a certain pressure and to
deliver it at a greater pressure, a line for the gas
delivered by the supercharger, and a valve in the
line for reducing the pressure of the delivered
gas; of means for opening the valve to reduce
a second piston mounted therein, a ?rst pitot tube
positioned in the inlet line, a line connecting the
?rst pitot tube with one end of the ?rst cylinder,
a line connected with the other end of the ?rst
the pressure of the delivered gas and thereby to
cylinder and with the inlet line so as to be sub
keep the supercharger Within the pumping limit,
ject to static pressure of gas therein, a line con
said means being responsive to arising of a con
necting one end of the second piston with the
dition in which the increase in gas pressure ef 10 line between the ?rst pitot tube and the said one
fected by the supercharger is in a neighborhood
end of the ?rst piston, a second pitot tube posi
of a value equal to a constant times the square
tioned in the outlet line, a line connecting the
of the velocity of the gas received by the super
other end of the second cylinder and the second
charger plus a constant times the absolute pres
pitot tube, a pivoted lever, means connecting the
sure of the gas received by the supercharger.
pistons with the lever, and means connecting the
6. The combination with a supercharger adapt
lever with the spill valve.
ed to receive gas at a certain pressure and to de
11. In combination, a supercharger, an inlet
liver it at a greater pressure, a line for the gas
line for gas to the supercharger, an outlet line
delivered by the supercharger, and a valve in the
for gas delivered by the supercharger, a spill valve
line for reducing the pressure of the delivered 20 connected with the outlet line, a ?rst cylinder, a
gas; of means for opening the valve to reduce
?rst piston mounted therein, a second cylinder, a
the pressure of the delivered gas and thereby to
second piston mounted therein, a ?rst pitot-tube
keep the supercharger within the pumping limit,
means positioned in the inlet line, a line connect
said means being responsive to arising of a con
ing the ?rst pitot-tube means with one end of the
dition in which the increase in gas pressure ef
?rst cylinder, a line connected with the other end
fected by the supercharger is in a neighborhood
of the ?rst cylinder and with the inlet line so as
of value equal to a constant times the square
to be subject to static pressure of gas therein, a
of the velocity of the gas received by the super
line connecting the ?rst pitot-tube means with
charger times the density of the gas received plus
one end of the second cylinder, a second pitot-tube
a constant times the absolute pressure of the gas
means positioned in the outlet line, a line con
received by the supercharger.
it at another greater pressure; of means keeping
necting the other end of the second cylinder and
the second pitot-tube means, a pivoted lever,
means connecting the pistons with the lever, and
means connecting the lever with the spill valve
the supercharger within the pumping limit, said
and including a servo-motor.
means being responsive to arising of a condition
in which the increase in gas pressure effected by
the supercharger is in a neighborhood of value
12. In combination, a supercharger, an inlet
line for gas to the supercharger, an outlet line
for gas delivered by the supercharger, a spill valve
connected with the outlet line, a ?rst cylinder, a
_
'7. The combination with a supercharger adapt
ed to receive gas at one pressure and to deliver
equal to a constant times the square of the veloc
ity of the gas received by the supercharger plus a ~10 ?rst piston mounted therein, a second cylinder,
constant times the absolute pressure of the gas
a second piston mounted therein, a ?rst pitot tube
received by the supercharger.
8. The combination with a supercharger adapt
positioned in the inlet line, a line connecting the
?rst pitot tube with one end of the ?rst cylinder,
a line connected with the other end of the ?rst
cylinder and with the inlet line so as to be sub
ject to static pressure of gas therein, a line con
necting one end of the second piston with the line
between the ?rst pitot tube and the said one end
ed to receive gas at one pressure and to deliver
it at another greater pressure; of means keeping
the supercharger within the pumping limit, said
means being responsive to arising of a condition
in which the increase in gas pressure effected by
the supercharger is in a neighborhood of Value
equal to a, constant times the square of the veloc
ity of the gas received by the supercharger times
the density of the gas received plus a constant
of the ?rst piston, a second pitot tube positioned
in the outlet line, a line connecting the other
, end of the second cylinder and the second pitot
times the absolute pressure of the gas received
by the supercharger.
9. In combination, a supercharger, an inlet line
for gas to the supercharger, an outlet line for gas
delivered by the supercharger, a spill valve con
nected with the outlet line, a ?rst cylinder, a ?rst
piston mounted therein, a second cylinder, 21. sec
ond piston mounted therein, a ?rst pitot-tube
means positioned in the inlet line, a line connect
ing the ?rst pitot-tube means with one end of the
?rst cylinder, a line connected with the other end
of the ?rst cylinder and with the inlet line so as
to ‘be subject to static pressure of gas therein, a
line connecting the ?rst pitot-tube means with
one end of the second cylinder, a second pitot
tube means positioned in the outlet line, a line
connecting the other end of the second cylinder
and the second pitot-tube means, a pivoted lever,
means connecting the pistons with the lever, and
means connecting the lever with the spill valve.
10. In combination, a supercharger, an inlet
line for gas to the supercharger, an outlet line for
gas delivered by the supercharger, a spill valve 75
tube, a pivoted lever, means connecting the pis
tons with the lever, and means connecting the
lever with the spill valve and including a servo
motor.
13. The combination with a supercharger
adapted to receive gas at one pressure and to de
liver it at another greater pressure; of means for
preventing the supercharger from exceeding the
pumping limit, said means comprising means re
sponsive to the velocity of the gas received by the
supercharger, means responsive to increase in gas
pressure effected by the supercharger, and means
responsive to absolute pressure of the gas de
livered by the supercharger, the three last men
tioned means cooperating with one another to
prevent exceeding of the pumping limit upon
arising of a condition in which the increase in gas
pressure is in a neighborhood of value equal to a
constant times the square of the velocity of the
gas received by the supercharger plus a constant
times the pressure of the gas delivered by the
supercharger.
14. The combination with a supercharger
adapted to receive gas at one pressure and to de
2,409,533
19
liver it at another greater pressure; of means for
preventing the supercharger from exceeding the
pumping limit, said means comprising means re
sponsive to the velocity and density of the gas
received by the supercharger, means responsive to
increase in gas pressure e?ected by the super
charger, and means responsive to absolute pres
sureof the gas delivered by the supercharger, the
three last mentioned means cooperating With one
another to prevent exceeding of the pumping lim
it upon arising of a condition in which the in
crease in gas pressure is in a neighborhood of
value equal to a constant times the square of the
20
limit, said means being responsive to arising of a
condition in which the increase in gas pressure
effected by the supercharger is in a neighborhood
of value equal to a constant times the square of
the velocity of the gas received by the super
charger plus a constant times the absolute pres
sure of the gas delivered by the supercharger.
15. The combination with a supercharger
adapted to receive gas at one pressure and to de
10 liver it at another greater pressure; of means
keeping’ the supercharger within the pumping
limit, said means responsive to arising of a condi
tion in which the increase in gas pressure ef
fected by‘ the supercharger is in a neighborhood
velocity of'the gas received by the supercharger
times the density of’ the gas received plus a con 15 of value equal to a constant times the square of
the velocity of the gas received by the super
stant times the absolute pressure of the gas de
charger times the density of the gas received plus
livered by the supercharger.
a constant times the absolute pressure of the gas
15. The combination with a supercharger
delivered by the supercharger.
adapted to receive gas at one pressure and to de
liver it at another greater pressure; of means 20
DAVID M. BURDEN.
keeping the supercharger Within the pumping
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