Note: Descriptions are shown in the official language in which they were submitted.
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Background of the Invention
Reference is made to United States Patent 3,964,259
which issued June 22, 1976, entitled Multi Condition Relief
~alve, which discloses a by-pass control valve for controlling
the flow of forced air to the exhaust pipe of an internal
combustion engine immediately upstream of an oxidizing
catalytic converter. An oxidizing catalytic converter needs
oxygen to function properly and additional oxygen can be
provided by an engine driven air pump which forces air into
an exhaust pipe of the engine upstream of the oxidizing
catalytic converter. The control valve illustrated in
United States Patent 3,964,259 is positioned in the air
passage from the air pump to the exhaust pipe and is provided
to shut off the air flow during periods of high acceleration
;- 15 and high deceleration as well as reducing the air flow during
periods of sustained high speeds. During rapid deceleration
of the vehicle, injected or forced air which may be injected
in the oxidizing catalytic converter may create a violent
type of burning in the exhaust system which may, in some
instances, result in audible afte:r fires. This is objectionable
noise and may create pressures that could be harmful to an
exhaust system.
- Thus, during rapid deceleration it is desirable to close
the main valve so that air may be by-passed into the
~ 25 atmosphere and not be provided to the secondary catalytic
- converter. In the aforementioned United States Patent 3,964,259
the pressures on opposite sides of the main diaphragm were
equalized through a separate vacuum control diaphragm
system thereby resulting in the main valve being moved to a
closed position in which position air was shut off to the
^ secondary oxidizing converter. The main valve and the by-
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pass valve were both mounted on a common stem which was
controlled by and connected to a main diaphragm which was
not immediately responsive to rapid deceleration.
B ef Descr ption of the Invention_ _ _ _
The control valve of the present invention for controll-
ing the flow of air through the forced air passage to the exhaust
pipe of an internal combustion engine has a main valve seat
positioned between inlet and outlet ports of the valve body
and when in a seated position blocks the flow of air to the
exhaust pipe. A separate by-pass valve is in an open
position when the main valve member is seat~d and air is
vented to the atmosphere from the forced air pump when the
main valve member is seated across the passageway between
the inlet and outlet ports. The main valve member and the
by-pass valve member are mounted on a common stem which is
controlled by a diaphragm. A separate auxiliary vent valve
is positioned in the main vacuum chamber and has a separate
stem connected thereto adjacent one end with an auxiliary
diaphragm connected adjacent the other end of the stem.
The vent valve diaphragrn has a vacuurn chamber on one side
thereof and a closed air chamber on the other side thereof
with an air bleed passage through the auxiliary diaphragm
between the enclosed air chamber and the auxiliary vacuum
chamber. Upon rapid deceleration, a high vacuum is applied
within the main vacuum chamber and the auxiliary vacuum
chamber to open the vent valve immediately thereby to vent
the main vacuum chamber to permit movement of the main valve
to a closed position in which position the by-pass valve is ~ ~ -
opened to allow the forced air to be discharged to atmosphere.
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The air bleed passage in the auxiliary diaphragm con-
trols the return of the vent valve to a closed position in whi~h
position the main valve chamber is again responsive to the
intake manifold vacuum. The delay which is controlled by the
size of the air bleed passage is provided by the auxiliary
diaphragm thereby delaying any reopening of the main valve
as the main valve chamber remains exposed to atmosphere
while the vent valve is in open position. Upon closing of
the vent valve, the vacuum, if between around three (3)
inches and eighteen (18) inches of mercury obtained during
normal engine operation, will aga~n open the main valve.
By delaying the closing of the vent valve to atmosphere,
adequate time is provided to permit the pollutants in the
exhaust pipe to be exhausted before additional air is
provided by the forced air passage to the exhaust pipe upon
subsequent reopening of the main valve. ~he spring holding
the main diaphragm and main valve in a closed position is
overcome by the application of manifold vacuum to the vacuum
chamber. The amount of vacuum required will be selected in
accordance with the requirements of the engine. However, it
is common to select a spring that will allow the diaphragm
to begin movement at a manifold vacuum in the order of three
(3) to six (6) inches of mercury thereby creating a main
valve open condition through the normal driving range of
manifold vacuums which lie outside the wide open throttle and
the deceleration range. In other words, when manifold
vacuum is between the lower limit of three (3) to six (6)
inches of mercury and a normal cruising vacuum of sixteen (16)
to eighteen (18) inches of mercury, the main valve will be
partially or fully open and will, thus,-pass air to the
exhaust system as previously described. ~ -~
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Brief Descr ption of the Drawing
_ _
The foregoing and other objec-ts, features and advantages
of the invention will be apparent from the following more
particular description of the preferred embodiments of the
invention, as illustrated in the accompanying drawings in
which reference characters refer to the same parts throughout
the different views.
Figure 1 is schematic view of an internal combustion
engine showing the control valve comprising the present
invention positioned in an air passage from an air pump to
the exhaust pipe to control the flow of air from the air pump
to the exhaust pipe;
Figure 2 is an enlarged side elevation of the air control
valve shown in figure 1 removed from the internal combustion
engine of figure 1'
Figure 3 is an enlarged section taken generally along
line 3-3 of figure Z and showing the main valve member in a
closed position with the flow of air being exhausted to
atmosphere with the by-pass valve member being in an open
position;
Figure 4 is a sectional view similar to figure 3 showing
the main valve member in open position with air being
supplied to the exhaust pipe and the by-pass valve member
being in a closed position to block the flow of air to ~ -
atmosphere;
Figure 5 is a bottom plan view of the control valve
assmebly shown in figures 2-4;
Figure 6 is an enlarged fragment of figure 3 showing the
air bleed passage in the auxiliary diaphragm to delay
the closing of the vent valve after opening; and
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Figure 7 is a longitudinal section of another embodi-
ment of the present invention illustrating a primarily sheet
metal construction for the body of the auxiliary diaphragm
and the vent valve controlled thereby.
Referring now to figure 1, an internal combustion
engine 11 has an intake manifold 13 thereon, an exhaust mani-
fold 15 and an exhaust pipe 17 leading from exhaust manifold
15. First and second catalytic converter beds 19 and 21 are
connected in series along exhaust pipe 17. The first cata-
lytic converter bed 19 is a reducing converter and is intended
to break down nitrogen - oxygen compounds into nitrogen gas and
oxygen gas. The second catalytic converter bed 21 is an oxidi-
zing type and is intended to convert hydrocarbons and carbon
monoxide (CO) into carbon dioxide (C02) and water vapor. The ~ -
second catalytic converter bed 21 requires additional oxygen
in order to function properly.
To furnish air for injecting into exhaust pipe 17 is
an air pump 25 driven by the crankshaft of the internal
combustion engine 11 by a suitable pulley belt (not shown) and
an air control valve assembly 27 comprising the present
inventicn to control the flow of air from air pump 25 to ex-
haust pipe 17. Air pump 25 injects air through air passage ~ -
29 to control valve assembly 27 and from control valve assembly
27 through air passage 31 to exhaust pipe 17. A vacuum line
33 extends from air valve assembly 27 to intake manifold 13
and the magnitude of the vacuum in vacuum line 33 controls the
flow of air through air control valve assmebly 27 from air
pump 25 to exhaust pipe 17.
Referring particularly to figure 3, control valve
assembly 27 has a main body 35 defining an inlet port 37,
an outlet port 39, a main valve seat 41, and a by-pass valve
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seat 43. A main valve member 45 controls air flow -through
central passage 47 and seat 41 through outlet 39. A by-pass
valve member 49 controls the flow of air through seat 43 to
atmosphere through muffler or filter 51 and retainer cup
member 53 having suitable openings 54 therein to atmosphere.
A valve stem 55 has main valve member 45 and by-pass
valve member 49 mounted thereon. A spring 57 extends
between main valve member 45 and by-pass member 49. Mounted
on one end of stem 55 is a spring retainer member 59 having an
inner spring 61 seated thereon between retainer member 59
and by-pass valve member 49 to urge by-pass valve member 49
downwardly toward seat 43. A second outer coil spring 63 is
seated between retainer 59 and valve body 35 to urge continu-
ously stem 55 toward the seated position of main valve member
45. By-pass valve member 49 is mounted for sliding movement
along the reduced end portion of valve stem 55 and when air
^ pressure within passage 47 reaches a sufficiently high magnitude,
by-pass valve member 49 will unseat against the bias of spring
61 which is!overcome by the increased air pressure and thereby
permit a flow of air to atmosphere until the pressure is re-
duced to a predetermined amount of which time by-pass valve
member 49 will reseat on seat 43. The end of stem 55 opposite
spring retainer member 59 is secured to a diaphragm 65 attached
about a peripheral portion to main body 35 of control air valve
assembly 27. A guide 67 is mounted within a central air chamber
69 and stem 55 is adapted to move axially relative to guide 67.
An air tight seal is not provided between central air chamber
69 and a secondary air ~hamber 71 beneath guide 67 and a small
leadkage of air occurs between chamber 71 and air chamber 69
about guide 67 to equalize the air pressure therebetween.
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A main vacuum chamber 73 is disposed on the side of
diaphragm 65 opposite chamber 71 and a vacuum is exerted
from line 33 through nipple 75 in bore 76 and small diameter
passage 77 connecting vacuum chamber 73 to bore 76.
A vent valve 79 is seated on seat 81 about a vent
opening 83 communicating with bore 84 which leads to atmos-
phere through a filter 85. A stem 87 secured to vent valve
member 79 adjacent one end is mounted adjacent its other end
to an auxiliary diaphragm 89 which is gripped about its
peripheral edge portion between a lower body portion 90 and an
outer enclosed generally cylindrically housing 91. A peripheral
flange 93 about housing 91 engages diaphragm 89 in gripping re
lation to lower body portion 90. Vacuum chamber 97 for diaphragm
89 is connected by relatively large vacuum passage 99 to bore
76 and line 33 to intake manifold 13.
Referring to figure 6, an enlarged fragment of diaphragm
89 is shown in which a lower support plate 101 is mounted on
one side of diaphragm 89 and an upper support plate 103 is
mounted on the other side thereof for clamping diaphragm 89
therebetween. Stem 86 has a lower end portion extending
through plates 101 and 103 to hold plates 101 and 103 into
clamping contact with diaphragm 89. A spring 105 extends be~
tween plate 103 and lower body portion 90 to urge continuously .
diaphragm 89 and vent valve member 79 to a seated closed posi-
tion on seat 81 to block flow of air into vacuum chamber 73
through vent passage 83 and bore 84 from atmosphere. End .
housing 91 provides an enclosed air chamber 107 and communica-
tion is provided between the closed air chamber 107 and
auxiliary vacuum chamber 97 through an ~ -
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106Z~6
opening 109 in lower plate 101, an opening 111 in diaphragm
89, and a small bleed port or passage 113 provided in rib
115 on upper plate 103. Rib 115 acts as a retainer for
adjacent spring 105 in addition to s-tiffening upper plate
103. Bleed passage 113 controls the flow of air between
chamber 107 and vacuum chamber 97.
In operation, pressurized air is supplied to inlet
port 37 by line 29 from air pump 25. Under normal engine
operation, for example, when a vehicle is bein~ driven at a
moderate steady speed, a vacuum applied to manifold vacuum
chamber 71 by vacuum line 33 is between around three (3)
inches and eighteen (18) inches of mercury. Under these
conditions, the vacuum difference between vacuum chamber 73
and chamber 71 is sufficient to overcome the bias of spring
63 and move valve stem 55 downwardly to unseat main valve member
45 and to seat by-pass valve member 49 onto seat 43. In this
position, as shown in figure 4, air travels through inlet :
port 37, air passage 47, air chamber 69, and outlet port 39
to be injected into exhaust pipe 17 through line 31.
However, assuming that a driver of a vehicle suddenly
accelerates rapidly, the vacuum in manifold vacuum chamber
73 and in the auxiliary vacuum chamber 97 drops to a
relatively low vacuum, for example, less than three (3) ~ -
inches of mercury, which is insufficient to overcome spring
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-- 63. Spring 63 then moves stem 55 and main valve member 45
to a seated position and opens by-pass valve member 49 :
thereby to permit a flow fo air from inlet 37 through seat 43
and to atmosphere through muffler 51.
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Assuming the vehicle is driven at a fast, relatively
steady speed, a normal vacuum of twelve (12) to fifteen (15)
inches of mercury is provided in manifold vacuum chamber
73 and auxiliary vacuum chamber 97 to hold valve stem 55
downwardly and main valve member 45 in an open position
with by-pass valve member 49 in a closed position. However,
as engine speed is increased, the speed at which combustion
engine 11 drives air pump 25 is increased so that air pump
25 increases the air pressure at inlet port 37 and the air
pressure acting against by-pass valve member 49. Eventually,
the pressure reaches a relatively large amount so that by-pass
valve member 49 is unseated against the bias of spring 61. As
engine speed is reduced, the by-pass valve member 49 will
reseat thereby to limit the actual amount of air at a fast`
steady speed as too great an amount of air in oxidizing cataly-
tic converter bed 21 might cause damage to the converter bed
resulting from relatively high temperatures being reached by
the increased amount of oxygen.
One of the main advantages in the present design is
obtained during deceleration of combustion engine 11. Assuming
that a driver of a vehicle suddenly takes his foot from an
accelerator pedal and thereby decelerates combustion engine
11, vacuum in manifold vacuum chamber 73 and in auxiliary
vacuum chamber 97 increases rapidly to twenty-two (22) to
twenty-five (25) inches of mercury, for example. It is noted
that vacuum port 99 is of greater diameter than vacuum port 77
and, thus, the vacuum in chamber 97 responds slightly faster
than the vacuum in vacuum chamber 73. Diaphragm 89 overcomes
spring 105 to open vent valve 79
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1062166
which open main vacuum chamber 73 to atmosphere through
vent passage 83 and bore 84. Venting of vacuum chamberi73
to atmosphere results in an increase in pressure in vacuum
chamber 73 to move valve stem 55 to a position in whilch main
valve member 45 is reseated and by-pass valve member 49 is
unseated thereby to permit the air to flow from inlet 37
through the by-pass opening to atmosphere. Vent valve 79
reseats itself when the pressure is generally equalized
between auxiliary vacuum chamber 97 and air chamber 107
through bleed opening 113. Thus, the speed at which vent
valve 79 is reseated is controlled by bleed opening 113 and
bleed opening 113 thus provides a delay in any reopening of
main valve member 45. This provides a time delay to permit
the pollutants to be emitted from exhaust pipe 17 before air
is again supplied to exhaust pipe 17 through line 31. The
time delay may be controlled and is dependent on the vacuum.
For example, a time delay of around 2.4 seconds is desirable
if the vacuum exerted is around twenty-two (22) inches of
mercury; around 1.5 to 2.85 seconds for sixteen (16) inches
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of mercury; and from 0.5 to 1.6 seconds for eight (8) inches
of mercury. Upon thè reseating of vent valve 79, the vacuum
in vacuum chamber 73 is again exerted and if between around
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three (3) inches and eighteen (18) inches of mercury, main
valve member 45 will reopen to again supply air to exhaust
pipe 17 through outlet 39 and line 31.
. Thus, the control valve assembly described herein while
cutting off the flow of air injected into an exhaust pipe
under a condition of high deceleration, aids the rapid
closing of the main valve member by the immediate opening
of a vent valve to atmosphere which permits the main vacuum
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106Z166
chamber for the main valve to communicate with atmosphere
rapidly. In addition, means are provided to delay the closing
of the vent valve for a predetermined time in order to permit
the pollutants to be emitted from the secondary or oxidizing
catalytic converter before àdditional air is supplied thereto.
The delay may be determined by the size of a bleed passage
as a vacuum will not be exerted in the main vacuum chamber
until the vent valve is closed.
In the event vacuum line 33 is severed or otherwise
damaged, there will be no vacuum applied to fitting 75 and
under such conditions, space 73 will be exposed to atmospheric
pressure. In such event, spring 63 will bias valve plate 45
to a closed condition and valve plate 49 will be moved away
froms its seat 43 so that all air from pump 25 is vented to
atmosphere.
Referring to figure 7, a separate embodiment of the
invention is illustrated in which a sheet metal body is
provided by vent valve member 79A and auxiliary diaphragm 89A. --
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An enclosed air chamber 107A is provlded on one side of
diaphragm 89A and a vacuum chamber 97A is provided on the
opposite side of diaphragm 89A. A bleed passage 113A is
provided in a rib 115A in a manner similar to that shown in
figure 6 for the embodiment of figures 1-6. A vacuum is
exerted from the intake manifold through vacuum nipples 75A.
During deceleration, a momentary pressure differential between
chamber 107A and vacuum chamber 97A opens vent valve 79A to
vent main vacuum chamber 73A to atmosphere through a vent
opening lZ0. The pressure between chamber 107A and chamber 97A
is equalized by bleed passage 113A to permit closing of vent
valve 79A after a controlled time delay. The functioning of
, the embodiment of figure 7 is generally identical to the
? functioning of the embodiment of figures 1-6.
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