Note: Descriptions are shown in the official language in which they were submitted.
l~lZ9g~0
This invention relates to a fuel volume meter comprising a housing,
through which flows the fuel to be measured and includes an inner chamber
with fuel inlet and fuel outlet, and a drive means for driving the input
of an indicating unit, for example, a printing and/or recording member in
response to the fuel volume flowing through the meter housing.
Fuel volume meters are used in the fuel feed system for different
types of vehicle engines. Such meters are utilized for example in such
cases when the fuel consumption is taxed and, further, when the condition
of the engine is to be judged on the basis of its fuel consumption per
distance driven or per running time and when it is to be determined whether
the engine requires a check-up. Such meters are previously known, at which
the fuel quantity can be read directly, for example according to U.S. Patent
3,805,602. Various methods of coupling a fuel meter into the fuel injection
system of diesel engines are described in U.S. Patents 3,750,463, 3,949,602,
3,817,273 and 3,672,394.
In the firstmentioned U.S. Patent 3,805,602 a meter is described which
accurately measures the volume or weight of the fuel consumed per time unit
by an engine. The meter comprises a piston, which is reciprocatingly driven
by the fuel pumped by an engine fuel pump through the meter. Said reciproca-
ting movement is transformed into a rotary movement by a cylinder cam, theoutput of which drives a tachometer or the like, which is calibrated to
indicate the fuel volume or weight consumed per time unit.
The mechanism of said meter for transforming the reciprocating move-
ment of the piston into a rotary movement and the valve mechanism of the
meter connecting the fuel inlet and outlet to the cylinder space of the piston
in order to cause the piston to reciprocate, are very complicated mechanically
and include many fault-prone details.
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A main ohject of the present invention is to produce a meter of the
afore-described kind, which is less complicated and more reliable in
operation compared with the known art.
The invention, thus, has the object of producing a fuel volume meter
of both recording and indicating type with a very high accuracy in measuring
the volume within a large flow range, for example between 0.1 and 100
litres/hour. The meter has a rotary output capable of being mechanically
loaded and to directly drive readable or printing counting mechanisms. The
meter does not require especially narrow manufacturing tolerances, but
permit its calibration in a simple way, for example by means of a screw-
driver. In view of the fact that gasoline and other fuels expand by about
1.1% per 10C, the meter is provided with temperature compensation means.
The meter, furthermore, is capable of being used with different types of
fuels, for example (non-lubricating) gasoline, diesel oil, engine kerosene
and other fuels in use or capable of being used. When combined with known
odometers, the possibility exists of printing both the distance run and
the fuel volume consumed. The meter, should be resistant to cold and heat
extremes, have a long service life and cause lowest possible pressure
drops in the measuring conduit. The meter should also be leak-proof
without complicated sealing arrangements.
According to one aspect of the invention, there is provided in a
liquid volume meter having a housing through which a volume of liquid
to be measured passes, the housing formed with an inner chamber including
an inlet and an outlet and having a drive means for driving a recording
means in response to the liquid flow through the housing, said drive
means comprising:
a) first reciprocating means comprising a first pair of opposing pistons
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connected by a first rod located within a first bore in the housing;
b) second reciprocating means comprising a sccond pair of opposing
pistons connected by a second rod located within a second bore in the
housing;
c) rotary valve means for successively connecting the inlet and outlet
to the first and second bores, the liquid flow through said housing as
controlled by said valve means imparting a reciprocating motion to said
first and second reciprocating means;
d) transformation means connected to said first and second reciprocating
means for converting the reciprocating motion into a rotary motion for
driving the recording means;
e) stroke adjusting means for adjusting a stroke of the reciprocating
motion by limiting the stroke of one of the reciprocating means by limit-
ing the stroke of the first rod wherein the first and second rods are
connected to the transformation means and the stroke of the second rod
is unaffected by said stroke adjusting means and said first rod has an
opening therein, the adjusting means and said first rod has an opening
therein, the adjusting means including a conical member supported by the
housing and projecting into said opening and means for adjusting the
depth of the conical member projecting into said opening whereby the
stroke of said first rod is adjustable depending upon the penetration
of the conical member into said opening.
According to another aspect of the invention there is provided
in a liquid volume meter having a housing through which a volume of
liquid to be measured passes, the housing formed with an inner chamber
including an inlet and an outlet and having a drive means for driving
a recording means in response to the liquid volume flow through the
}
housing, said drive means comprising:
a) first reciprocating means located within a first bore in the housing;
b) second reciprocating means located within a second bore in the
housing;
c) valve means for successively connecting the inlet and outlet to the
first and second bores, the liquid flow through said housing as controlled
by said valve means imparting a reciprocating motion to said first and
second reciprocating means;
d) transformation means connected to said first and second reciprocating
means for converting the reciprocating motion into a rotary motion for
driving the recording means, wherein said first reciprocating means is
a first pair of opposing pistons connected by a first rod and said second
reciprocating means is a second pair of opposing pistons connected by a
second rod, said first and second rods connected to said transformation
means, said first rod is perpendicular to said second rod, said first rod
has a first central transverse elongated opening therein and said second
rod has a second central transverse elongated opening therein juxtapositioned
over the first opening and wherein a crank is located within said first - :and second openings and is connected to said valve means, said first pair
of opposing pistons is a first left piston forming a first left chamber
within the first bore of an opposing first right piston forming an opposing
first right chamber within the first bore; and said second pair of opposing
pistons is a second left piston forming a second left chamber within the
second bore and an opposing second right piston forming an opposing second
right chamber within the second bore; and wherein said valve means
successively exclusively connects the inlet selectively to a given one
of said chambers and, in a corresponding manner, said valve means
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.. .- . .
o
successively exclusively connects the outlet to the opposing chamber of
said given chamber, said housing defines an inner chamber connected to
the inlet and having a plane valve surface having a central hole
communicating with the outlet; further including four second holes
equidistantly arranged about said central hole, each said second hole
communicating with one of said chambers, respectively; a circular plate
valve connected to said crank and disposed over the plane valve surface
providing rotational movement in response to said reciprocating motion
thereby selectively connecting the inlet and outlet to opposing chambers,
said circular plate valve is a disc having a lower circular recess on
the side of the disc contacti.ng the plane valve surface, said recess
having a diameter substantially equal to the sum of the distance between
central hole and a given one of said second holes added to the diameter
of said central hole added to the diameter of the given one of said
second holes; and wherein the axis of rotation of said crank coincides
with the central axis of the central hole whereby liquid flow through
the housing causes reciprocating motion of said pistons which is converted
into rotary motion by said crank to drive the recording means, said first
rod has an opening therein, and further including a calibration means
having a conical member supported by the housing and projecting into
said opening and means for adjusting the depth of the conical member
: projecting into said opening whereby the stroke of said first reciprocating
means and, consequently, said drive means is adjustable depending upon
the penetration of the conical member into said opening, and said means
for adjusting is comprised of a temperature compensating means for adjust-
ing the penetration of the conical member in response to the temperature
of the liquid within the housing.
.~
For the purpose of illustration but not of limitation, embodiments
of the invention are hereinafter described with reference to the drawings,
in which:
Fig. 1 shows the meter through section A-A of Fig. 2.
Fig. 2 is the section B-B of Fig. 1.
Fig. 3 shows the movement transferring components in the meter housing.
Figs. 4-6 show a piston rubber membrane from above and in diametral
section respectively, and Fig. 5 shows a detail of the membrane edge on an
enlarged scale.
Fig. 7 is a cross-section of the meter housing cover.
Figs. 8-9 show another simplified meter housing cover from below and
in diametral section, respectively.
Figs. 10-11 are sections corresponding to Fig. 1 and, respectively,
Fig. 2 of a simplified meter housing.
Figs. 12-14 show a piston rod from the side, from above and in a
lateral section, respectively.
Figs. 15-16 show a pair of intersecting simplified piston rods in
lateral section and from aboove, respectively.
Figs. 17-18 show a circular plane valve disc in diametral section
from above, respectively.
Fig. 19 shows the housing from above, with the sealing surface of
the valve disc shaded.
Fig. 20 shows a valve disc compression spring from above.
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. ~ ~
Fig. 21 shows the meter housing from the side.
Fig. 22 is a partial view of the meter housing coupled together with a
card-printing unit according to SW-PS 336 920 and 354 370.
Figs.23-26 show piston rods to explain the adjustment of the meter.
Figs. 27, 29 and 30 show different ways of coupling the meter into the
engine fuel feed system.
Fig. 28 shows a known fuel feed system for a diesel engine.
Figs. 31-32 illustrate the automatic temperature compensation of the
meter.
Figs. 33-34 show an indicating unit to be coupled to the housing of
the meter flow portion to replace the card-printing unit according to Fig. 22.
The fuel volume meter according to the invention comprises a volume
meter portion in the form of a four-cylinder "radial engine arrangement"
comprising a plane slide for flow directioning. The plane slide is spring-
and pressure-loaded, in such a manner, that with increasing mechanic load on
the output the pressure difference between the inlet and the outlet increases
and the plane slide increasingly is pressed against its opposite sealing
; surface.
The fuel meter housing 13, which in Fig. 1 is shown by way of a central
section along A-A in Fig. 2 and in Fig. 2 by way of a cross-section along
B-B in Fig. 1, comprises four oppositely paired cylinder bores 80 and 82 and
81 and 83. The cast housing has a square solid bottom 133 seen in Fig. 2 from
above, the upper surface of which serves as a valve surface 134. In said
bottom four bores 70-73 opposed in pairs and one central hore 135 are provided.
Bore 135 is connected to a fuel outlet passageway 12. A bore 136 is provided
to the left in the bottom of the left-hand cylinder kore 82 connected to a
fuel inlet 11, which in this way is connected to the interior of the housing
13. The bores 70-73 are located at 90 intervals on a circle having its
9~)
centre in the centre of the central outlet bore 135. Each bore 70-73 is
connected through transverse bores 9, 10 in the bottom 133 to an annular
passageway 85 about the respective cylinder bore each in one side wall of
the housing. In this embodiment two transverse bores 9 and 10 are shown
extending from the bore 71. The transverse bores extending from the remain-
ing bores 70, 72 and 73 are indicated in Fig. 2 only by their dash central
lines 137.
In Fig. 1 a circular plane valve plate or disc 20 is shown to be
slidable on the surface 134. On said plate a valve spring 18 with a central
opening 44 is located. The function of the valve plate 20 in co-operation
with the openings 135 and 70-73 will be described later with reference to
Figs. 10, 11 and 19.
The fuel inlet 11 and the fuel outlet 12 each have a threaded
connecting nipple 14, of which only the nipple for the outlet is shown in
Fig. 2.
Of the remaining details shown in Figs. 1 and 2 can be mentioned a
cylinder head 1 with an annular groove 2 and a second annular groove 90.
The grooves are connected relative to each other through four bores or
holes 3. Between the cylinder head 1 and the opposed housing wall a rubber
membrane 17 is clamped and is attached to the end of a partially shown
piston rod 8 between a clamping plate 15 thereon and a clamping plate 16,
which is secured by a screw 25 and a peripheral edge 74 of clamping plate 16
projects outwardly to the right as shown in Fig. 2. It is understood that
the remaining three cylinder bores upwardly, downwardly and to the left in
Fig. 2 have corresponding arrangements (not shown) of piston rod, piston head
and rubber membrane. At the top of Fig. 1 an O-ring 24 is shown which seals
against a cover described below. The pistons herein are membrane pistons
in order to easily prevent leakage about the pistons. However it is under-
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stood that the usual piston type with a suitable rubber lip sealing also can
be used.
In Figures 1 and 2, it can be seen how the membrane pistons operate.
The cylinder head 1 abuts the edge of membrane 17 which seals both inwardly
and outwardly. Holes 58 provided in the membrane edge (see Fig. 4) connect
the annular groove 85 in the housing with the groove 2, holes 3 and second
annular groove 90 in the cylinder head and establish connection between the
cylinder bore 80 and the hole 70. The membrane 17 forms a fold about the
clamping disc 16 and is held bulging-out by the fuel pressure in the
interior of the housing 13. Upon the reciprocatory piston movement, the
membrane rolls against the inside of the cylinder head and the outside of
the clamping disc. Thus, there is no friction, but only some kind of
"kneading" of the membrane rubber about the clamping disc.
In Fig. 3 parts of the movement transfer mechanism in the fuel meter
according to the invention are shown. It shows, starting at the top of the
figure a sealing disc 5 constituting the uppermost portion of the flow
portion of the meter. Below disc 5 a magnetic coupling is shown designated
generally by 7 comprises a central magnet holder 19 of, for example, nylon
which holds a magnetic ring 28 of, for example, ferrite and rests with a
protrusion 138 against the lower surface of the disc 5 for rotation relative
to the same, and comprises a hub 47, into which a sleeve member 139 is
inserted. Sleeve member 139 is a part of a disc portion 29 provided with an
upright circumferential wall 45. The magnetic ring 28 is clamped between
an edge flange 46 on the upper end of the wall 45 and a stepped portion 140
on the disc portion 29. The wall 45 preferably is provided with height slots
to facilitate the clamping of the magnetic ring 28. Into a central square
blind bore 30 in the portion 29 a square pin 34 on the end of a crank unit
is inserted, which unit generally is designated by 35 and comprises a
3`~
crankshaft 32, a crank disc 31 rigidly connected to the crankshaft and a
crank 33 connected eccentrically and rigidly to the crank disc 31, which
crank terminates in an end pin 49. A cover 6 shown in greater detail in
Fig. 7 comprises a hub 48, in which the crankshaft 32 is rotatable in an
upper bushing 21 and a lower bushing 22. A loose disc 141 is located between
the bushing 22 and the crank disc 31. On the crank 33 an upper roller 36 and
a lower roller 37 are supported which are inserted in holes in piston rods 8
in the manner described below. A spring catch 84 of normal U-shape holds
the rollers on the crank 33. The end pin 49 is rotatable in a bore 51 in a
hub 50 of the plane valve plate 20, which includes a central circular recess
53 and rests with its lower surface 146 against the previously mentioned
sealing surface 134 on the bottom portion 133 of the housing 130 Into a
second hub 50 or sleeve portion of the cover 6 an adjusting cone 4 is threaded,
the function of which is described below.
The rubber membrane 17 referred to in connection with Figo 2 is
shown in greater detail in Figs. 4-60 The membrane includes a central hole 54
for the passage of the screw 25 in Figo 2, a bottom 55, an inclined membrane
wall 56 and a peripheral edge 57. Said edge has an edge flange 59 and is
provided with a plurality of holes 58.
The said cover 6 shown by way of a cross-section in Figo 7 includes
holes 67 for its attachment to the housing 13 and holes 68 for attaching a
recording, indicating and/or printing member of the meter according to the
invention, which member is described below. A depression 142 in the cover
has an inclined wall 63, a bottom 62 with two through bores 61 ~of which
only one is shown) and the aforementioned hubs 48 and 60 (Fig. 3) with
bores 65 and 66 respectively. An O-ring 23 for sealing against the disc
5 (Fig. 3) is located on a shoulder 64 about the periphery of the depression
142.
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In Figs. 12-14 one of the two mutually alike piston rods 8 in the
fuel flow portion of the meter according to the invention is shown. A
clamping plate 15 is attached to each end of the piston rod, for example by
spot welding on a folded-up portion 143 at both ends of the rod. The portion
143 includes a recess 145, and the rod end has a recess 144. The plate 15 is
provided with a central screw hole 69. As shown in top view in Fig. 13, the
piston rod further includes a longitudinally elongated hole 26 and central
transversely elongated hole 27 for a purpose described below.
The plane slide disc or valve plate 20 shown in Figs. 17 and 18 is a
circular disc of nylon or another suitable material with a peripheral edge
flange 52 and, as mentioned above, a central blind bore 51, a hub 50 and a
circumferential surface 146. In Fig. 18 it is shown from above.
The valve spring 18 shown from above in Figs. 1 and 20 comprises
three legs 75-77 folded downward along folding lines 79 and is provided with
a central hole 44. The ends 147 of the legs are intended to rest against
the inner wall of the flange 52 (Fig. 17) of the valve plate 20 in order to
press the plate into sealing engagement with the sealing surface 134 ~Fig. 1).
The spring is made of a suitable spring material.
Fig. 21 is a lateral view of the housing from the inlet end. The wall
2Q includes screw holes 88 for attaching the cylinder head 1. Also shown are the
inlet 11 and the aforementioned bores 9 and 10. Numeral 87 designates a side
wall of the housing bottom 133. A circular shoulder 86 extends around the
cylinder bore, and inside said shoulder is the circular groove 85, inside of
which is defining edge 89.
Fig. 22 is a partial view of a card printing device, for example accord-
ing to the patent specifications 336 920 and 354 370, mounted on the flow
portion of the fuel volume meter according to the invention. The printing
mechanism is designated by 39, and a rotatable cover thereof is designated by
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$~)
120. The printing mechanism is attached to the cover 6 by means of columns
121 with a nut 127 screwed onto the column end. The housing is shown partially
with cylinder heads l mounted thereon and with its sealing disc 5 and its
magnetic coupling 7.
Centrally on the bottom of the printing mechanism its input shaft is
located, which comprises an end square pin 126 and a stationary collar 125.
A bearing disc 122 is attached to the bottom. A loose disc 123 is provided
on the shaft and is held by a ~-shaped spring catch 124. A magnet holder 38
similar to the holder 19 is attached to the shaft end 126, which is inserted
into a square hole in the portion 38, which rests with a protrusion 128 on
the disc 5. As can be seen~ in order to avoid sealing of the rotating output
shaft from the flow portion, this rotary movement is transferred in a
magnetic way, i.e. the movement of the unit 7 is transferred magnetically
through the disc 5 (which, of course, is of a non-ferromagnetic material)
to the magnetic ring 149 of the input shaft to the mechanism 39.
In Figs. 33 and 34 a different embodiment is shown, comprising an
indicating volume counter to be connected to the flow portion of the meter
according to the invention.
According to Fig. 33, the counter or indicating unit 40 seen from above
comprises a scale 43 with a pointer 42 and counting mechanism 41. At the
lateral view according to Fig. 34 the unit in question is shown to comprise
holding columns 91 for attachment analogous to the unit 39 shown in Fig. 22,
and with a threaded end 103. The input shaft 95 is provided with a magnetic
disc 94 for co-operation with the magnetic coupling 7. The shaft 95 is
supported in a bearing 99 in a hood 102 of the counting mechanism and provided
with a gear wheel 98 meshing with a gear wheel 101 on a pointer shaft 100.
Numeral 92 designates a driving gear wheel for the counting mechanism 41
meshing with a gear rim 105 on a first counting mechanism wheel 106. The
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counting mechanism wheels 106 are located on cm axle 96. On an axle 97
decimal transfer wheels 93 are arranged to co-operate with gear rims on the
respective counting mechanism wheel 106, except for the wheel located far-
thest to the right which meshes with the driving wheel 92 mounted on an
axle 104 of its own. The axle carries on its opposite end a corresponding
gear wheel 151, which meshes with a screw worm 150 at the end of the shaft
95, whereby the movement of the input shaft 95 is transferred to the counting
mechanism 41.
In Figs. 8 and 9 a simplified design of the cover 6 is attached in
sealed manner upon the meter housing 13. The outgoing shaft (crankshaft 32)
is mounted in said cover and provided, as previously, with two easily
movable rollers 36,37. Fig. 11 shows section D-D in Fig. 10 and Fig. 10
shows section C-C in Fig. 11; housing 13 is adjusted to accommodate the
cover 6 in Figs. 8 and 9. In Figs. 15 and 16 a pair of piston rods 8 for
this embodiment are shown, and in Figs. 17 and 18 a corresponding plane valve
disc 20 is shown. Fig. 19 shows from above the housing 13 with the contact
surface 146 of the disc 20, the valve surface 134 being shown slantly dashed,
which two surfaces are accurately plane and smooth. The plate of slide disc
20 in Fig. 19 has a design adjusted to the embodiment shown in Figs. 1-2.
The mode of operation of the plate or disc 20 in co-operation with the
bores or holes in the valve surface 134 is as follows. The pin 49 (Fig. 3)
is inserted into the hole Sl in the valve plate 20 (Fig. 17) and into the
hole 44 (Fig. 1) in the valve spring 18. The plate 20 then ispressed by
said spring against the valve surface 134. When the valve plate 20 with
its contact surface 146 covers the holes 71 and 73 in Figs. 10 and 11, the
hole 72 over the recess 53 in the plate 20 is connected to the outlet hole
135. The inlet hole 136 is connected to the hole 70 via the inner chamber of
the housing 13. When the crank disc 31 is turned through one quarter of a
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revolution in counterclockwise direction (to the position in Fig. 19),
the holes 70 and 72 are closed, and the outlet hole 135 is connected to the
hole 73. The hole 71 is connected to the fuel inlet.
Continued rotation implies that at the rotation of one revolution of
the disc 20 the inlet hole 136 is caused in due succession to communicate
with the holes leading to the cylinder bores 80, 81, 82 and 83, while the
outlet hole at the same time is connected to the cylinder bores or cylinder
chambers 82, 83, 80 and, respectively, 81. The intermediate positions
between the extreme positions of the disc 20, to the left, to the right,
downwardly and upwardly, provide a gradual opening to the cylinder chamber
next in turn to open fully. The same applies to the outlet side. The
pistons in the cylinder bores will successively slide in pairs, because
these pistons are opposedly connected in pairs by means of the intersecting
piston rods 8, which are provided with a transverse groove 27 in their centre,
which grooves intersect each other (Fig. 16) to form an opening for the
rollers 36, 37 (Fig. 3), which rotate freely on the crank 33 and, thus, are
driven freely by the corresponding piston rod.
The pressure in the chamber 80 from the inlet 136 presses the piston
pair in the chambers 80 and 82 to the left in Figs. 10-11. The chamber 82
is then emptied to outlet 135. At the same time, the upper roller 36 on
the crank 33 is actuated by a force directed to the left. The crank disc
31 with the crank 33 and the two rollers 36, 37 start to rotate counterclock-
wise. The valve plate 20 participates in the movement of the crank 33 and
gradually opens the inlet to the chamber 81 and the chamber 83 to the out-
let. The piston pair 81,83 then move downward and press with their piston
rod 8 on the lower roller 37, so that the counterclockwise rotation in this
way is maintained.
The load being taken out from the p;ston rods 8 is only of such a size
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o
as to overcome the friction of the plate Z0 against the valve surface 134,
and the load required for driving magnetically, for example a counting
mechanism, with the outgoing shaft. Friction forces in the pistons and flow
resistance in the different passageways are fully balanced by forces in the
piston rods and the difference between inlet pressure and outlet pressure,
without loading the crank disc 31 and its bearings.
In Fig. 19 the number 129 designates the location of the outer
periphery of the plate 20, the number 130 designates the location of the inner
periphery, and the number 131 designates the location of the centre of the
plate 20.
The adjustment or calibration of the meter is described with reference
to Figs. 23-26, of which Fig. 26 shows, in section, a piston rod 8 with end
clamping plate 15 for the rubber membrane, transversely elongated hole 27 and
longitudinally elongated hole 26, the end of the crank mechanism with crank
shaft 32, crank disc 31, crank 33 and rollers 36, 37 and an adjusting cone 4
with adjusting screw 148 inserted into the longitudinally elongated hole 26.
Figs. 23-25 show the piston rod 8 as seen from above.
When the rollers 36,37 fit well in the transverse holes of the piston
rods, the liquid amount V flowing through per shaft revolution is as follows:
2Q V = 4 x 2 x r x ~4D
wherein 4 are the four pistons, 2r is the stroke length, which is equal to
twice the crank radius r, and the last term is the piston area ~D = piston
diameter). Consequently,
V = 27r r D2
Logarithmation yields:
ln V = ln 2 ~ + ln r + 2x ln D
Derivation yields
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,
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9~)
dV = 0 + dr + 2dD
It is apparent that a tolerance of 1% in the crank radius (for example r = 4,
dr = 0,04, dr/r - 1/100 = 1 %) yie]ds dV/V = l %, consequently a tolerance
of measured volume = 1 %. A tolerance of 1 % in the piston diameter (for
example D = 38, dD = 0,38, dD/D = l/100 = 1 %) yields dV/V = 2 %, consequently
of measured volume = 2%. At a tolerance error of 1 % both for r and D, a
faulty indication by 3 % can be obtained. Instead of tightening up the
tolerance requirements, it is preferred to adjust the volume per revolution
to its rated value VB. The meter, therefore, shall comprise a calibration
possibility.
Calibration is carried out as follows:
The stroke length for one piston pair is adjusted so as to deviate
from 2r ~see Figs. 23-24).
In Fig. 23 the diameter of the roller and the width of the
transverse hole both are equal to d. The stroke length is 2r. In Fig. 24
the diameter of the roller has been reduced to dl. The piston road then can
increase its stroke length beyond previous 2r. The increase is equal to the
clearance between the hole and the small roller. The maximum stroke length,
thus, is
= 2r + (d - dl)
The piston rod also passes through this extra distance, driven
by the pressure on the piston from the inlet. After a corresponding end
position, the crank disc is driven in counterclockwise direction by the
intersecting piston rod and its roller of "normal size". After the fully
drawn angular position in the Figure has been passed, the valve disc 20
directs the inlet pressure to the cylinder 82, and the piston rod moves to
the right and actuates the small roller first after the clearance d - dl
has been consumed. The diametral end position is drawn in a dashed manner
in Fig. 24.
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' ' .
In Figo 25 the stroke length instead has been reduced by the
clearance, which yields the minimum stroke length
= 2r - (d - dl~
The plane valve disc 20 and the intersecting piston rod in this case as well
as in the foregoing case manage the passage over the end position drawn in
fully line in the Figure. The adjusting cone 4, which can be raised or
lowered, runs in the longitudinal slit 26 in one of the two intersecting
piston rods and controls the stroke lengthO When the cone is screwed up
(Fig. 24), the slit end contacts the narrow end ~1 of the cone. The maximum
stroke length is
S = a + 0 -
max
When the cone 4 is screwed down (FigsO 25-26), the end of the
longitudinal slit contacts the large end 0 of the cone. The minimum stroke
length is
S = a
mln
Adjustment, thus, is to be made so that
S = a + 0 ~ 01= 2r + (d - d )
max
and
Smin = a = 2r - (d dl)
When the height of the cone (cone angle) is adjusted to the pitch
of the thread, and when stroke lengths and diameters are taken into considera-
tion, it is possible, for example, that the rotation of the cone through one
revolution corresponds to a change in volume by 1 % per revolutionO
The corresponding calibration of the meter then is extremely
simple. One starts with the cone in central position, and with passing an
accurately measured volume through the meter. When an attached instrument
shows more than the measured volume, for example 1.5% too much, the adjusting
cone must be screwed up one and a half revolutions. The volume per revolution
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shall increase by 1.5% for obtaining agreement between indicated volume and
real volume. There is, certainly, a non-linearity about the revolution, but
every entire revolution yet corresponds to a definite volume. Alternatively
to the adjusting cone 4, an adjusting screw 78 in the cylinder head 1 could
instead be used, which screw acts on the clamping disc 16 for limiting the
stroke length (Fig. 11). In Figs. 31 and 32 a means for automatic
temperature compensation at a meter according to the invention is shown by
way of a lateral view and from above respectively.
An adjusting cone 110 of a type similar to the adjusting cone 4
in Fig. 3 and provided, for example, to engage with a longitudinal long
hole 26 in a piston rod 8 has an end 112 and is attached at the upper end to
a bimetal spring 108 comprised in a pair of such springs, which are held
together at the ends by lock springs 109. The upper bimetal spring, and
therewith the cone 110, can be adjusted by an adjusting screw 107. The
bimetal springs 108 are bathed in the liquid in the meter. The arrow 111
shows the movement of the cone 110 at increasing temperature.
Fuel expands in heat by about 1.1% per 10C. When the fuel
tank is filled with fuel of the temperature +10C from an earth tank and
the fuel is consumed at +30C, the fuel meter will show that the volume
consumed exceeds the tanked volume by (30 - 10) x 1.1 = 2.2 %. Therefore,
a temperature compensator, for example according to Figs, 31-32, preferably
is provided in order to obtain full agreement between tanked volume at one
temperature and consumed volume at another temperature. The weight of the
fuel at tanking and consuming is in each case the same, and the fuel meter,
thus, can be said to be "weight adjusted".
Different ways of coupling in the fuel meter into fuel feed sys-
tems are dealt with in connection with Figs. 27-30.
Fig. 27 shows a fuel meter 113 coupled into the fuel feed
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system for a gasoline engine in an automobile for example. The meter is
coupled into the fuel line between the fuel pump 115 and the carburettor
(arrow 118), alternatively before the pump 115 (shown by dashed lines).
The fuel tank is designated by 114.
In Fig. 28 a normally coupled fuel feed system for a diesel
engine is shown without the fuel meter according to the invention. The
flow of the fuel is indicated by arrows in the conduits. The arrow ll9
designates the discharge direction to the engine, and 116 is the injection
pump
In diesel engines for automobiles the coupling of the fuel meter
is not as simple as at a gasoline engine according to Fig. 27. A diesel
engine comprises two pumps, i.e. one feed pump 115 and one injection pump
116. The injection pump is controlled by the engine load and number of
revolutions. The fuel not used for injection usually is returned to the
fuel tank. The feed pump has excess capacity and the fuel not being taken
up by the injection pump also is returned to the tank. Fuel, which was
subjected to pressure in the pumps, has an increased temperature. This
fuel preferably is cooled by returning it to the tank exposed to slip stream.
Fig. 29 shows the most simple coupling of a fuel meter according
to the invention at a diesel engine. In this case, however, the return fuel
is not cooled, which should be desirable, because a diesel engine seems to
loose in efficiency when being operated with heated fuel.
In Fig. 30 another way of coupling is shown, at which the return
fuel flows through a cooling coil 117 in the tank 114 and is delivered in cold
state to a T-pipe after the fuel meter. The meter 113 in this case is loaded
by a warmer fuel, which should be advantageous, because in cold diesel fuel
there is risk of precipitation of heavy oil fractions, which can stop the fuel
flow. The cooling coil 117 can be replaced by a separate cooling tank where
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1;29~0
air bubbles in the return fuel can be separated.
Among the advantages of the fuel volume meter according to the
invention can be mentioned its simplicity in design, its easy adjusting by
means of a screw-driver, its rotary output movement, which is coupled
magnetically to a counting mechanism in a printing and/or indicating unit,
the possibility of measuring very small fuel flows, the feature that the
mechanical output does not extend through the housing, so that no rotary
member requires sealing, the reliable sealing of the housing in general
against fuel leakage, large possible tolerances at the manufacture of struc-
tural details of the meter, its temperature compensation, its applicabilityto different types of fuels, the possibility of combining the meter with
devices indicating and recording the distance, which are driven by the vehicle
in question and so on.
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