GB1581722A - Fluid flow modulator valve assemblies - Google Patents
Fluid flow modulator valve assemblies Download PDFInfo
- Publication number
- GB1581722A GB1581722A GB4000576A GB4000576A GB1581722A GB 1581722 A GB1581722 A GB 1581722A GB 4000576 A GB4000576 A GB 4000576A GB 4000576 A GB4000576 A GB 4000576A GB 1581722 A GB1581722 A GB 1581722A
- Authority
- GB
- United Kingdom
- Prior art keywords
- valve
- air
- air valve
- weight
- fluid flow
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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- 239000012530 fluid Substances 0.000 title claims description 49
- 230000000712 assembly Effects 0.000 title description 2
- 238000000429 assembly Methods 0.000 title description 2
- 239000000446 fuel Substances 0.000 claims description 81
- 239000000203 mixture Substances 0.000 claims description 31
- 230000033001 locomotion Effects 0.000 claims description 26
- 230000009471 action Effects 0.000 claims description 19
- 230000008859 change Effects 0.000 claims description 12
- 238000002485 combustion reaction Methods 0.000 claims description 11
- 230000004044 response Effects 0.000 claims description 10
- 238000011144 upstream manufacturing Methods 0.000 claims description 5
- 238000006073 displacement reaction Methods 0.000 claims description 4
- 239000000463 material Substances 0.000 claims description 4
- 230000002093 peripheral effect Effects 0.000 claims description 4
- 239000004033 plastic Substances 0.000 claims description 4
- 229920003023 plastic Polymers 0.000 claims description 4
- 230000015572 biosynthetic process Effects 0.000 claims description 2
- 239000002131 composite material Substances 0.000 claims description 2
- 230000003993 interaction Effects 0.000 claims description 2
- 230000010355 oscillation Effects 0.000 claims description 2
- 230000003068 static effect Effects 0.000 claims description 2
- 230000006698 induction Effects 0.000 description 7
- 239000002775 capsule Substances 0.000 description 5
- 238000007789 sealing Methods 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- 230000001419 dependent effect Effects 0.000 description 2
- 239000010956 nickel silver Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 229910001369 Brass Inorganic materials 0.000 description 1
- 230000001133 acceleration Effects 0.000 description 1
- 125000000218 acetic acid group Chemical group C(C)(=O)* 0.000 description 1
- 230000002301 combined effect Effects 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 239000000498 cooling water Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 229910001092 metal group alloy Inorganic materials 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- MOFOBJHOKRNACT-UHFFFAOYSA-N nickel silver Chemical compound [Ni].[Ag] MOFOBJHOKRNACT-UHFFFAOYSA-N 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 238000010079 rubber tapping Methods 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M1/00—Carburettors with means for facilitating engine's starting or its idling below operational temperatures
- F02M1/04—Carburettors with means for facilitating engine's starting or its idling below operational temperatures the means to facilitate starting or idling being auxiliary carburetting apparatus able to be put into, and out of, operation, e.g. having automatically-operated disc valves
- F02M1/046—Auxiliary carburetting apparatus controlled by piston valves
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Fuel-Injection Apparatus (AREA)
Description
(54) IMPROVEMENTS IN OR RELATING TO FLUID FLOW
MODULATOR VALVE ASSEMBLIES
(71) We, THE ZENITH CAR
BURETTER COMPANY LIMITED, a
British Company of Honeypot Lane, Stanmore, Middlesex, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement::
This invention relates to fluid flow modulator valve assemblies which comprise a body in which an opening is formed and a fluid flow modulator valve which co-operates with the body to determine the effective .cross-sectional area of the opening and thereby to modulate fluid flow through the opening, the modulator valve being biassed in use of the assembly so that it seeks an equilibrium position relative to the body for steady state conditions of fluid flow through the opening and being arranged so that it will move relative to the body to seek a different equilibrium position in response to a change in the loading that acts upon it in use.More particularly, although not exclusively, this invention relates to cold start fuel/air mixture supply devices for internal combustion engines, the devices including such a fluid flow modulator valve assembly, the fluid flow modulator valve being an air valve.
Such cold start fuel/air mixture supply devices comprise a body which serves as the body of the fluid flow modulator valve assembly and in which a through passage is formed, the body of the device being adapted for connection to the inlet manifold casing of the engine so that one end of the through passage is connected to the inlet manifold of the engine such that air can be drawn through that passage by engine suction. fuel supply means from which fuel can be drawn for mixture with air which flows through the through passage. and throttling means for metering the flow of fuel/air mixture drawn from the through passage by engine suction in use of the device. the air valve co-operating with an associated valve seat to vary the area of the opening of the fluid flow modulator valve assembly which is a part of the through passage upstream of the throttling means, the air valve thereby being adapted to control a depression which is established within that part of the through passage between the opening and the throttling means in operation of the engine to which the device is connected in use, that depression serving as the fuel demand signal that draws fuel into the through passage from the fuel supply means, there being yieldable biassing means for urging the air valve towards the valve seat against the action upon the air valve of such a depression which tends to separate the air valve from the valve seat.Such a cold start fuel/air mixture supply device shall be referred to in the remainder of this Specification as "a cold start fuel/air mixture supply device of the kind referred to above".
Usually the throttling means of a cold start fuel/air mixture supply device of the kind referred to above comprise a throttle valve which is arranged so as to tend to be moved by engine suction into a position in which it minimises the flow of air past it to the engine in use of the device and biassing means which bias the throttle valve into an open position at least when the device is in use. Also a thermostatically-controlled movable stop is usually provided for limiting movement of the throttle valve towards the position in which it minimises the flow of air past it to the engine to which the device is connected in use. the thermostatic control means for the movable stop being adapted to be responsive to the temperature of the engine to which the device is connected in use and thereby to determine the position of the movable stop in relation to the temperature of that engine so that permitted closing movement of the throttle valve is minimised when the engine is cold and is increased as the engine warms up towards its normal operating temperature, whereby movement of the throttle valve to the position in which it minimises air flow past it to the engine is permitted.Hence the constitution of fuel/air mixture supplied to the engine is changed firstly at the end of the engine cranking period, when the engine begins to run under its own power, whereafter it is changed progressively as the engine warms up to its normal operating temperature at which there is no further need for extra fuel or air to be supplied to the engine by a cold start fuel/air mixture supply device.
The yieldable biassing means of a preferred form of cold start fuel/air mixture supply device of the kind referred to above comprise first yieldable biassing means, which act directly upon the air valve, and second yieldable biassing means which act upon a plunger which is movable relative to the air valve, the plunger having a surface which is exposed to the pressure that is existent in a space which is for connection to the inlet manifold of the internal combustion engine so that when the device is installed on an internal combustion engine, the load exerted by said second yieldable biassing means upon the plunger to urge the plunger towards the air valve is reduced by the thrust due to the action upon the said surface of the plunger of a depression which is substantially that which is established in the inlet manifold of the engine.The arrangement of that preferred form of cold start fuel/air mixture supply device of the kind referred to above is such that the plunger exerts a thrust upon the air valve to oppose the action upon the air valve of the depression that is established within the through passage between the opening and the throttling means in use of the device only when the load applied to the plunger by said second yieldable biassing means exceeds the suction forces upon that plunger due to the action of engine suction upon that plunger.
Our co-pending Patent Application No.
9387/76 (Serial no. 1576425) discloses that a stop. which prevents the plunger being urged by said second yieldable biassing means into abutment with the air valve when the air valve is seated. may be provided, the stop ensuring that the minimum clearance between the plunger and the valve seat is sufficient for the air valve to move between the valve seat and the plunger to modulate air flow into that part of the through passage between the opening and the throttling means and thereby to control the depression that is established within that part of the through passage in use of the device without the air valve being drawn by that depression into contact with the plunger with sufficient force to displace the plunger against the action of the second yieldable biassing means once the engine has warmed up to predetermined temperature below the normal operating temperature at which there is no further need for extra fuel or air to be supplied to the engine by a cold start fuel/ air mixture supply device.
We have found that there is a tendency for the fuel demand signal to vary inconsistently during operation of the preferred form of cold start fuel/air mixture supply device of the kind referred to above.
An object of this invention is to minimize the tendency for fluid pressure downstream of an opening which is formed in a body to vary inconsistently during operation of a fluid flow modulator valve which is provided to modulate fluid flow through that opening.
A more specific object of the invention is to minimise the tendency for the fuel demand signal to vary inconsistently during operation of a cold start fuel/air mixture supply device of the kind referred to above.
According to this invention there is provided a fluid flow modulator valve assembly comprising a body in which an opening is formed and a fluid flow modulator valve which co-operates with the body to determine the effective cross-sectional area of the opening and thereby to modulate fluid flow through the opening. the modulator valve being biassed in use of the assembly so that it seeks an equilibrium position relative to the body for steady state conditions of fluid flow through the opening and being arranged so that it will move relative to the body to seek a different equilibrium position in response to any change in the loading that acts upon it in use, wherein the modulator valve is interengaged with a weight between a spaced pair of stops which are formed on one of the valve and the weight and which limit movement of the modulator valve relative to the weight to seek a new equilibrium position. the effective cross-sectional area of the modulator valve in a plane which is transverse to the direction of fluid flow through the opening being significantly greater than the effective crosssectional area of the weight in that plane and the weight of the modulator valve being significantly less than that of the weight so that the response of the modulator valve to any change in the fluid loading upon the interengaged assembly of the modulator valve and the weight is quicker than is the response of the weight to that change.
Preferably the weight depends from the modulator valve. Conveniently the weight has one portion which projects through an aperture which is formed in the modulator valve so that lateral displacement of the modulator valve relative to the weight is limited by the weight. The weight may have another portion of uniform cross-section which is a sliding fit in a corresponding guide passage which is formed in the body or in a component which is supported by the body.
Conveniently the weight and the modulator valve are coaxial.
Preferably the invention is embodied in a cold start fuel/air mixture supply device of the kind referred to above.
Where the yieldable biassing means of the cold start fuel/air mixture supply device comprise first yieldable biassing means which act directly upon the air valve and second yieldable biassing means which act upon a plunger to urge that plunger towards the air valve, the plunger being movable relative to the air valve and having a surface which is exposed to the pressure that is existent in a space which is for connection to the inlet manifold of the internal combustion engine so that, when the device is installed on an internal combustion engine, the load exerted by said second yieldable biassing means upon the plunger to urge the plunger towards the air valve is reduced by the thrust due to the action upon the said surface of the plunger of a depression which is substantially that which is established in the inlet manifold of the engine, the weight, which comprises a spindle upon which the air valve is fitted, is engaged for sliding movement in a bore in the plunger.
One embodiment of this invention will be described now by way of example with reference to the accompanying drawings of which Figure 1 is a plan view of an automatic cold start fuel/air mixture supply device in which this invention is embodied, the various parts being shown in the positions they adopt when the engine is cold and not running;
Figure 2 is a partial section on the line II-II of Figure 1, showing the throttle valve and fuel metering needle; and
Figure 3 is a sectioned fragmentary view of the cold start fuel/air mixing supply device shown in Figures 1 and 2 which comprises that part of Figure 2 that is in elevation sectioned on the line II-II of Figure 1, the various parts being shown in the positions they adopt when the engine is idling whilst cold.
An internal combustion engine installation for a motor vehicle includes an air/fuel induction system which comprises an engine inlet manifold to which the induction passage of a carburetter is connected.
The air/fuel induction system also includes a fully automatic cold start fuel/air mixture supply device which comprises a body l1 which has a through passage 12 fomed in if. The through passage 12 comprises a chamber 13 and a downstream portion 14 which has a smaller cross-section than does the chamber 13. The body 11 is adapted for connection to the inlet manifold casing of the engine so that the downstream end 15 of the downstream passage portion 14 is connected to the induction passage of the carburetter downstream of the driver operable throttle valve.
The chamber 13 is closed at its upstream end by a closure plate 16 which has an opening 17 formed in it. The opening 17 is displaced laterally with respect to the junction of the chamber 13 and the downstream passage portion 14.
A profiled plug valve 18 co-operates with the orifice 20 that is formed at the junction of the chamber 13 and the downstream passage portion 14 in order to control fluid flow from the chamber 13 to the downstream passage portion 14. The plug valve 18 is carried by a rod 19 which is guided for rectilinear movement along its axis by being engaged slidably within a tubular guide 21 which is integral with the closure plate 16.
A rectilinearly movable air valve 22 cooperates with a valve seat 23 to close the opening 17 in the closure plate 16. The air valve 22 is annular and comprises a thin flat central disc portion 24 with an enlarged annulus 25 at its outer periphery. The radially outer surface 26 of the annulus portion 25 tapers towards the opening 17 in a non-linear convexly-curved manner. The air valve conveniently comprises a moulding of a suitable plastics material such as an acetyl resin. The annulus 25, which extends away from the disc portion 24 in a direction parallel to the axis of the disc portion 24 and away from the opening 17, co-operates with the central disc portion 24 to form a substantially cylindrical recess 27.
A stepped spindle 28 has one portion 29 which projects through the central aperture 30 of the annular valve 22. The remainder 31 of the spindle 28 projects out from the recess 27 away from the annular valve 22. The diameter of the spindle portion 29 is less than the diameter of the central aperture 30 so that there is a clearance between the spindle portion 29 and the central disc portion 24 of the annular valve 22. The diameter of the remainder or main portion 31 of the spindle 28 is greater than the diameter of the central aperture 30 but is somewhat less than a quarter of the maximum diameter of the annular valve 22. The spindle 28 is formed of a metal or metal alloy, such as nickel silver or brass, so that its weight is significantly greater than that of the plastics annular valve 22.A circumferential groove 32 is formed in the smaller diameter spindle portion 29 and is spaced from the shoulder 33 between the smaller diameter spindle portion 29 and the main spindle portion 31 by a distance which is approximately one and a half times the thickness of the central disc poriton 24 of the annular valve 22. A circlip 34 is engaged within the circumferential groove 32 and has an outside diameter which is greater than the diameter of the central aperture 30. Hence the shoulder 33 and the circlip 34 comprise a spaced pair of stops which limit relative axial movement between the annular valve 22 and the spindle 28. the radially inner peripheral portion of the annular valve 22 being located between the shoulder 33 and the circlip 34.
The main portion 31 of the spindle 28 is cylindrical and is engaged for sliding movement within a closed ended bore 35 which is formed coaxially in a plunger 36. The plunger 36 is stepped having a central portion 37 between two end portions 38 and 39.
The central plunger portion 37 has a circumferential groove 41 of V-cross-section formed at its centre. The diameter of the end plunger portion 38, in which the closed ended bore 35 is formed, is less than that of the central plunger 37 and greater than the maximum diameter of the other end plunger portion 39 which is of cruciform crosssection. The central plunger portion 37 is engaged for sliding movement within the bore 42 of a tubular insert 43 which is spigotted into a blind bore 44 which is formed in the body 11 coaxially with the annular valve seat 23 and which has its mouth in the wall of the chamber 13. The tubular insert 43 projects into the chamber 13 and has an inwardly directed radial flange 45 formed at its end nearer to the annular valve seat 23.
The larger diameter end plunger portion 38 projects through the aperture formed by the radial flange 45. The closed inner end portion of the blind bore 44 is connected to the induction passage of the carburetter just downstream of the driver-operable throttle valve by a short pipe 40. The two annular peripheral portions of the central plunger portions 37 that are separated by the groove 41 comprise a labyrinth seal which enables a substantial pressure difference across the plunger portion 36 to be maintained. An annular nut 46 is screwed into a tapped por
tion of the bore 42 of the tubular insert 43 which is formed at the end of that bore 42 adjacent the closed inner end of the blind bore 44.The annular nut 46 comprises an annular flange 47 upon which the threads are furmed and which is formed at the end of a tubular portion 48 that is nearer to the closed
inner end of the blind bore 44. A coil spring
49 reacts against the annular flange 47 and
urges the central plunger portion 37 towards
the inwardly-directed radial flange 45 so that
there is a space between the plunger 36 and
the closed end of the blind bore 44. The
cruciform section end plunger portion 39
slides within the bore of the tubular nut por
tion 48.Another coil spring 51. which is sea
ted within the recess 27 so that it acts directly
upon the air valve 22 and urges it towards the
valve seat 23, reacts against the flange 52 of a
flanged tubular abutment member 53 which
is mounted slidably upon the tubular insert 43. that part of the tubular insert 43 that
projects into the chamber 13 being spigotted
into the bore of the tubular abutment
member 53. The loading of coil spring 49 can
be adjusted during assembly by rotation of the annular nut 46. The loading of the coil spring 51 can be adjusted by manipulation of a screw (not shown) which is screwed into the body 11 and which abuts the tubular abutment member 53.
The axes of the plunger 36, the spindle 28 and the blind bore 44 are parallel to the axis of the plug valve rod 19 and are coincident with the axes of the air valve 22 and the annular valve seat 23. All these axes are vertical when the body 11 is mounted in position as part of the air/fuel induction system of the engine, the spindle 28 depending from the air valve 22 which is supported by the coil spring 51. Normally the air valve 22 controls communication between the chamber 13 and an enclosure which is formed between the body 11 and a cup-shaped cover of sheet material (not shown). The cover has an inlet port which is connected to the outlet of the air cleaner which is also connected to the upstream end of the induction passage of the carburetter.
Another through passage 54 which is formed within the body 11 of the cold start device, has a stepped main bore portion 55 which is substantially parallel with the axis of the plug valve support rod 19 and a laterally extending end bore portion 56 which is connected to the fuel chamber of the carburetter. A tubular insert is fitted into the stepped main bore portion 55 and projects from that bore portion 55 into the enclosure that is formed between the body 11 and the cupshaped cover. The bore of the tubular insert has an intermediate portion 59 of reduced diameter which is spaced from the end of that bore that projects into said enclosure by a distance which is greater than the distance by which it is spaced from the other end of that bore.The portion 57 of the bore that extends between the reduced diameter bore portion 59 and the end of the bore that projects into said enclosure communicates with the chamber 13 via a radial passage 58 in the tubular insert and an aligned passaged in the body 11 and may communicate with said enclosure by a passage (not shown) in the body 11 which would include a restriction which serves as an air metering orifice. The laterally extending end bore portion 56, the inner end of the stepped bore portion 55, the reduced diameter bore portion 59, and the passage 58 together comprise a fuel passage and the reduced diameter bore portion 59 comprises a metering orifice for metering fuel flow through the fuel passage to the chamber 13.
A cylindrical member 61 carries a profiled fuel metering needle 62 and slides within the end bore portion 57 of the tubular insert. The profiled needle 62 projects through the fuel metering orifice that is formed by the reduced diameter bore portion 59 and carries an annular sealing ring 63 at its largest
diameter end which is the end that is attached
to the cylindrical member 61. The end of the
cylindrical member 61 remote from the pro
filed needle 62 is coupled to the plug valve
support rod 19 by an arm 64 which is fixed at
one end to the rod 19 and which extends
laterally from it.The plug valve 18 and the
fuel metering needle 62, which are coupled
together and guided for rectilinear move
ment along parallel paths, are urged by a coil
spring 65 into the respective positions in
which the effective cross-sectional area of
each of the orifices 20 and 59 with which they
co-operate is at its greatest.
A beam 66 is mounted pivotally on a hinge
pin 67 and carries a first peg 68 at its end nearer the plug valve rod 19, a second peg 69
between the first peg 68 and the hinge pin 67
and a third peg 71 at its other end. A temper
ature sensitive capsule is housed within a
water jacket 72 which is mounted on the
body I 1 and which is provided with tappings
by which it is to be connected into the cooling
water system of the internal combustion
engine so that the capsule is responsive to engine temperature. The temperature sensi
tive capsule is filled with wax or other suit
able substance having a high thermal expan
sion coefficient. The arrangement is such
that, with increase in temperature, the wax or
other substance expands and moves an
actuator rod 73 in a direction along its length
against the action of a coil spring 74.The
axes of the actuator rod 73 and spring 74 are
in a plane which is normal to the plane that
includes the axes of the plug valve rod 19 and
the fuel metering needle 62. The actuator
rod 73 carries an annular flange 75. The third
peg 71 extends between the flange 75 and the
water jacket 72, the axes of the third peg 71
and the rod 73 being mutually perpendicular.
A torsion spring 76 reacts against the body 11 and acts on the beam 66 so that the third
peg 71 is held in contact with the flange 75
and the first peg 68 is in contact with the
outer limb 77 of a cranked arm 78 at the
same time, the cranked arm 78 being fixed to
the arm 64 that couples the plug valve sup
port rod 19 and the fuel metering needle
cylindrical support member 61 together. Part
of the arm 64 is shown broken away in Figure
1 in order to reveal the peg 69.
When the engine is cold. the temperature
sensitive capsule allows the actuator rod 73
to be held by the respective coil spring 74 in a
position in which its annular flange 75 is
nearest to the water jacket 72. Thus, due to
the interengagement of the third peg 71 and
the annular flange 75. the beam 66 is held
against the action of the torsion spring 76 in
the position in which the first peg 68 is furth
est from the body 11. the torsion spring 76
being extended. The arm 64 that links the
plug valve support rod 19 and the fuel meter
ing needle cylindrical support member 61 is held in its position furthest from the body 11 by the coil spring 65 so that the outer limb 77 of the cranked arm 78 is in contact with the first peg 68. Thus the plug valve 18 is spaced from the orifice 20.The second peg 69 is spaced from the arm 64 when the outer limb 77 of the cranked arm 78 is in contact with the first peg 68 and serves as a stop which limits movement of the plug valve 18 towards the orifice 20 by limiting movement of the arm 64 towards the body 11. The air valve 22 is seated upon the valve seat 23 by the action of the coil springs 51 and 49, which comprise first and second yieldable biassing means respectively, the plunger 36 touching the air valve 22 and having its central portion 37 spaced from the inwardly directed annular flange 45.
When the engine is cranked for starting, the plug valve member 18 and the fuel metering needle 62 remain substantially in the positions just described. Suction exerted by the engine displaces the air valve 22 and the plunger 36 relative to the valve seat 23 and causes air to be drawn into the chamber 13.
Also fuel is drawn in metered quantities
through the fuel passage. Such fuel is drawn through the fuel metering orifice 59 at a high rate because the profiled needle 62 is withdrawn and the effective area of the fuel metering orifice 59 is at its greatest.
When the cold engine begins to run under its own power, increased suction exerted by the engine displaces the air valve 22 further from the valve seat 23 and also draws the plunger 36 towards the closed end of the blind bore 44 so that the displacement of the air valve 22 from its valve seat 23 can be maximised and is determined solely by the depression in the chamber 13 and by the action of the first coil spring 51 that acts directly upon the air valve 22. Hence the depression that is established in that chamber 13 is maintained at or below a maximum depression which is dependent upon the loading of the coil spring 51 and which is the depression that is required to hold the air valve 22 unseated.The plug valve 18 is urged towards its associated orifice 20 until the arm
64 that links its support rod 19 and the fuel metering needle cylindrical support member
61 abuts the second peg 69 which prevents further movement of the plug valve 18 towards the orifice 20 and movement of the fuel metering needle 62 with it.
As the temperature of the engine
increases, the temperature sensitive capsule
urges the actuator rod 73 against the action
of the respective coil spring 74 thus allowing the beam 66 to be rotated by the action of the
torsion spring 76 in the direction which
moves the first peg 68 and the second peg 69
towards the body 11 of the cold start fuel/ air
mixture supply device.Assuming that idling
conditions are maintained until the engine warms up to its normal operating temperature. such movement of the second peg 69 allows following movement of the arm 64 that links the plug valve support rod 19 and the fuel metering needle cylindrical support member 61 due to the action of engine suction on the plug valve member 18, so that the plug valve 18 is moved to reduce the effective area of the associated orifice 20 and thus to reduce the mass flow of air through the through passage 12, and the profiled needle 62 is moved with it to reduce the effective area of the fuel metering orifice 59.Such movement of the plug valve member 18 with movement of the actuator rod 73 continues until the temperature of the engine has increased to the normal working temperature whereupon the plug valve 18 reaches the end of its stroke remote from the closure plate 16 and effectively closes the associated orifice 20 in the air supply passage 12. The sealing ring 63 carried by the profiled needle 62 seats upon the shoulder formed between the portions 57 and 59 of the bore of the tubular insert and closes the fuel metering orifice 59. The interconnection of the plug valve support rod 19, the arm 64 and the fuel metering needle cylindrical support member 61 is arranged so that the sealing ring 63 seats to close the fuel metering orifice 59 at substantially the same time as the through passage 12 is closed effectively by the plug valve member 18.
The rate of flow of fuel through the fuel metering orifice 59 is dependent upon the effective area of the fuel metering orifice 59 and thus is altered in accordance with changes in engine temperature by the profiled needle 62 which is allowed to move with changes in engine temperature. Likewise the rate of flow of fuel/air mixture through the orifice 20 associated with the profiled plug valve 18 is altered in accordance with changes in engine temperature by the profiled plug valve 18 which is allowed to move with changes in engine temperature. Conveniently the profile of the plug valve 18 is selected so that the idling speed of the engine is maintained constant throughout the period required for the engine to warm up to its normal operating temperature.
When the driver-operable throttle valve is opened to increase the speed of the engine.
the depression in the inlet manifold is reduced with the result that the force on the plunger 36 due to engine suction is reduced also. If the depression in the inlet manifold is reduced sufficiently. the loading of the second coil spring 49 that acts upon the plunger 36 will exceed the force on the plunger 36 due to engine suction. Hence the plunger 36 will be urged towards the air valve 22 and the coil spring 49 will extend. At Icast initially and when the engine is cold the depression in the chamber 13 of the through passage 12 is sufficiently high for the air valve 22 to be spaced sufficiently from the valve seat 23 for the plunger 36 to abut the air valve 22 so that the plunger 36 will impart a thrust to the air valve 22.Such a thrust, together with the action of the first coil spring 51 that acts directly upon the air valve 22, opposes the action upon the air valve 22 of the depression that is established in the chamber 13 of the air supply passage 12 and urges the air valve 22 towards the valve seat 23 to reduce the effective area of the opening 17 and effect an increase in the depression within that chamber 13. The ratio of fuel to air that is drawn through the orifice 20 that is associated with the plug valve 18 is increased by the combined effects of the reduction in the effective area of the opening 17 and the increase in the depression within the chamber 13.The force that is imparted by the plunger 36 to the air valve 22 to urge that air valve 22 towards the valve seat 23 comprises the difference between the loading of the second coil spring 49 and the force on the plunger 36 due to engine suction. The crosssectional area of the central portion 37 of the plunger 36, the effective area of the air valve 22 that is exposed to the depression that is established in the chamber 13 of the through passage 12 and the loading of the first and second coil springs 51 and 49 that act upon the air valve 22 and the plunger 36 respectively are selected so that the depression within the chamber 13 in the through passage 12 is a function of the inverse of the depression that exists in the inlet manifold when the engine is running and the plunger 36 is in contact with the air valve 22 and for as long as the depression in the inlet manifold is adequate for such a depression to be maintained in the chamber 13 of the air supply passage 12.
The depression in the inlet manifold tends to fall when the driver operable throttle valve is opened fully to accelerate the vehicle.
Hence the suction force exerted upon the plug valve 18 may be reduced to a force which is less than the opposing force that is exerted by the respective coil spring 65 so that the plug valve 18 and the fuel metering needle 62 are moved to increase the effective areas of the orifices 20 and 59 with which they are associated. Such movement of the plug valve 18 and the fuel metering needle 62 is limited by engagement of the outer limb 77 of the cranked arm 78 with the first peg 68.
Hence the increase in the quantity of the air/fuel mixture required by the engine for acceleration and the increase in the proportion of fuel to air in that mixture can be achieved by the automatic operation of the cold start fuel/air mixture supply device so that any tendency for the engine to stall because insufficient fuel is supplied to it can be countered by such operation of the device.
The air valve 22 is static in a position in which there is equilibrium between the downthrust upon it due to air flow through the opening 17 and the depression in the chamber 13 on the one hand and the spring load upon it due to the action of the first coil spring 51 and, where appropriate, the second coil spring 49 that acts upon it through the plunger 36, when conditions of air flow through the opening are steady. Any change in any one of the forces that act upon the air valve 22 for any one of the various reasons described above results in the air valve 22 no longer being in equilibrium so that it is moved by the unbalanced force that acts upon it to seek a new position in which such equilibrium conditions are re-established.
Formation of the air valve 22 from a lightweight plastics material and the interaction of the radially inner peripheral portion of the air valve 22 with the spaced pair of stops afforded by the circlip 34 and the shoulder 33 of the spindle 28 minimises the tendency for the air valve 22 to oscillate about the new equilibrium position that it seeks and this minimises a tendency for the depression in the chamber 13, which is the fuel demand signal, to vary inconsistently during operation of the device. It is believed that the spindle 28 acts as a weight or slug to absorb the kinetic energy of the moving air valve 22 and thereby to damp such oscillations by impact of a respective one of the spaced pair of stops with the air valve 22 as that air valve 22 tends to oscillate about the new equilibrium position that it seeks.The air valve 22 separates from the circlip 34 during such movement so that the spindle 28 falls until arrested and supported by the air valve 22 in the new equilibrium position. Minimisation of the weight of the air valve 22 minimises the kinetic energy generated by movement of the air valve 22.
A two part composite air valve substantially as described with reference to and as illustrated in Figures 4 and 5 of the drawings that accompany the Complete Specification filed in connection with our co-pending
Patent Application No. 15094/76 (Serial no.
1581721) may be used in place of the air valve 22 described above with reference to
Figure 3 of the accompanying drawings.
WHAT WE CLAIM IS:
1. A fluid flow modulator valve assembly comprising a body in which an opening is formed and a fluid flow modulator valve which co-operates with the body to determine the effective cross-sectional area of the opening and thereby to modulate fluid flow through the opening. the modulator valve being biassed in use of the assembly so that it seeks an equilibrium position relative to the body for steady state conditions of fluid flow through the opening and being arranged so that it will move relative to the body to seek a different equilibrium position in response to any change in the loading that acts upon it in use, wherein the modulator valve is interengaged with a weight between a spaced pair of stops which are formed on one of the valve and the weight and which limit movement of the modulator valve relative to the weight to seek a new equilibrium position, the effective cross-sectional area of the modulator valve in a plane which is transverse to the direction of fluid flow through the opening being significantly greater than the effective crosssectional area of the weight in that plane and the weight of the modulator valve being significantly less than that of the weight so that the response of the modulator valve to any change in the fluid loading upon the interengaged assembly of the modulator valve and the weight is quicker than is the response of the weight to that change.
2. A fluid flow modulator valve assembly as claimed in Claim 1, wherein the weight depends from the modulator valve.
3. A fluid flow modulator valve assembly as claimed in Claim 1 or Claim 2, wherein the weight has one portion which projects through an aperture which is formed in the modulator valve so that lateral displacement of the modulator valve relative to the weight is limited by the weight.
4. A fluid flow modulator valve assembly as claimed in Claim 3, wherein the weight has another portion of uniform cross-section which is a sliding fit in a corresponding guide passage which is formed in the body or in a component which is supported by the body.
5. A fluid flow modulator valve assembly as claimed in any one of Claims 1 to 4, wherein the weight and the modulator valve are coaxial.
6. A cold start fuel/air mixture supply device for an internal combustion engine, the device having a fluid flow modulator valve assembly according to any one of Claims 1 to 5 embodied in it and comprising a body which forms the body of the fluid flow modulator valve assembly and in which a through passage is formed, the body of the device being adapted for connection to the inlet manifold casing of the engine so that one end of the through passage is connected to the inlet manifold of the engine such that air can be drawn through that passage by engine suction, fuel supply means from which fuel can be drawn for mixture with air which flows through the through passage, and throttling means for metering the flow of fuel/air mixture drawn from the through passage by engine suction in use of the device, the fluid flow modulator valve being an air valve which co-operates with an associated valve seat to vary the area of the opening of the fluid flow modulator valve assembly which is a part of the through passage upstream of the throttling means. the air valve thereby being
**WARNING** end of DESC field may overlap start of CLMS **.
Claims (9)
- **WARNING** start of CLMS field may overlap end of DESC **.The air valve 22 is static in a position in which there is equilibrium between the downthrust upon it due to air flow through the opening 17 and the depression in the chamber 13 on the one hand and the spring load upon it due to the action of the first coil spring 51 and, where appropriate, the second coil spring 49 that acts upon it through the plunger 36, when conditions of air flow through the opening are steady. Any change in any one of the forces that act upon the air valve 22 for any one of the various reasons described above results in the air valve 22 no longer being in equilibrium so that it is moved by the unbalanced force that acts upon it to seek a new position in which such equilibrium conditions are re-established.Formation of the air valve 22 from a lightweight plastics material and the interaction of the radially inner peripheral portion of the air valve 22 with the spaced pair of stops afforded by the circlip 34 and the shoulder 33 of the spindle 28 minimises the tendency for the air valve 22 to oscillate about the new equilibrium position that it seeks and this minimises a tendency for the depression in the chamber 13, which is the fuel demand signal, to vary inconsistently during operation of the device. It is believed that the spindle 28 acts as a weight or slug to absorb the kinetic energy of the moving air valve 22 and thereby to damp such oscillations by impact of a respective one of the spaced pair of stops with the air valve 22 as that air valve 22 tends to oscillate about the new equilibrium position that it seeks.The air valve 22 separates from the circlip 34 during such movement so that the spindle 28 falls until arrested and supported by the air valve 22 in the new equilibrium position. Minimisation of the weight of the air valve 22 minimises the kinetic energy generated by movement of the air valve 22.A two part composite air valve substantially as described with reference to and as illustrated in Figures 4 and 5 of the drawings that accompany the Complete Specification filed in connection with our co-pending Patent Application No. 15094/76 (Serial no.1581721) may be used in place of the air valve 22 described above with reference to Figure 3 of the accompanying drawings.WHAT WE CLAIM IS: 1. A fluid flow modulator valve assembly comprising a body in which an opening is formed and a fluid flow modulator valve which co-operates with the body to determine the effective cross-sectional area of the opening and thereby to modulate fluid flow through the opening. the modulator valve being biassed in use of the assembly so that it seeks an equilibrium position relative to the body for steady state conditions of fluid flow through the opening and being arranged so that it will move relative to the body to seek a different equilibrium position in response to any change in the loading that acts upon it in use, wherein the modulator valve is interengaged with a weight between a spaced pair of stops which are formed on one of the valve and the weight and which limit movement of the modulator valve relative to the weight to seek a new equilibrium position, the effective cross-sectional area of the modulator valve in a plane which is transverse to the direction of fluid flow through the opening being significantly greater than the effective crosssectional area of the weight in that plane and the weight of the modulator valve being significantly less than that of the weight so that the response of the modulator valve to any change in the fluid loading upon the interengaged assembly of the modulator valve and the weight is quicker than is the response of the weight to that change.
- 2. A fluid flow modulator valve assembly as claimed in Claim 1, wherein the weight depends from the modulator valve.
- 3. A fluid flow modulator valve assembly as claimed in Claim 1 or Claim 2, wherein the weight has one portion which projects through an aperture which is formed in the modulator valve so that lateral displacement of the modulator valve relative to the weight is limited by the weight.
- 4. A fluid flow modulator valve assembly as claimed in Claim 3, wherein the weight has another portion of uniform cross-section which is a sliding fit in a corresponding guide passage which is formed in the body or in a component which is supported by the body.
- 5. A fluid flow modulator valve assembly as claimed in any one of Claims 1 to 4, wherein the weight and the modulator valve are coaxial.
- 6. A cold start fuel/air mixture supply device for an internal combustion engine, the device having a fluid flow modulator valve assembly according to any one of Claims 1 to 5 embodied in it and comprising a body which forms the body of the fluid flow modulator valve assembly and in which a through passage is formed, the body of the device being adapted for connection to the inlet manifold casing of the engine so that one end of the through passage is connected to the inlet manifold of the engine such that air can be drawn through that passage by engine suction, fuel supply means from which fuel can be drawn for mixture with air which flows through the through passage, and throttling means for metering the flow of fuel/air mixture drawn from the through passage by engine suction in use of the device, the fluid flow modulator valve being an air valve which co-operates with an associated valve seat to vary the area of the opening of the fluid flow modulator valve assembly which is a part of the through passage upstream of the throttling means. the air valve thereby beingadapted to control a depression which is established within that part of the through passage between the opening and the throttling means in operation of the engine to which the device is connected in use, that depression serving as the fuel demand signal that draws fuel into the through passage from the fuel supply means, there being yieldable biassing means for urging the air valve towards the valve seat against the action upon the air valve of such a depression which tends to separate the air valve from the valve seat.
- 7. A cold start fuel/air mixture supply device according to Claim 6, wherein the yieldable biassing means comprise first yieldable biassing means which act directly upon the air valve and second yieldable biassing means which act upon a plunger to urge that plunger towards the air valve, the plunger being movable relative to the air valve and having a surface which is exposed to the pressure that is existent in a space which is for connection to the inlet manifold of the internal combustion engine so that, when the device is installed on an internal combustion engine, the load exerted by said second yieldable biassing means upon the plunger to urge the plunger towards the air valve is reduced by the thrust due to the action upon the said surface of the plunger of a depression which is substantially that which is established in the inlet manifold of the engine, the weight, which comprises a spindle upon which the air valve is fitted, is engaged for sliding movement in a bore in the plunger.
- 8. A fluid flow modulator valve assembly substantially as described hereinbefore with reference to and as illustrated in the accompanying drawings.
- 9. A cold start fuel/air mixture supply device substantially as described hereinbefore with reference to and as illustrated in the accompanying drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB4000576A GB1581722A (en) | 1977-09-27 | 1977-09-27 | Fluid flow modulator valve assemblies |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB4000576A GB1581722A (en) | 1977-09-27 | 1977-09-27 | Fluid flow modulator valve assemblies |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1581722A true GB1581722A (en) | 1980-12-17 |
Family
ID=10412684
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB4000576A Expired GB1581722A (en) | 1977-09-27 | 1977-09-27 | Fluid flow modulator valve assemblies |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB1581722A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2481215A1 (en) * | 1980-04-25 | 1981-10-30 | Nissan Motor | PURGE VALVE FOR A QUICK-ACTING MASTER-CYLINDER |
-
1977
- 1977-09-27 GB GB4000576A patent/GB1581722A/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2481215A1 (en) * | 1980-04-25 | 1981-10-30 | Nissan Motor | PURGE VALVE FOR A QUICK-ACTING MASTER-CYLINDER |
| US4571944A (en) * | 1980-04-25 | 1986-02-25 | Nissan Motor Company, Limited | Blow-off valve in a quick take-up master cylinder |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PS | Patent sealed | ||
| PCNP | Patent ceased through non-payment of renewal fee |