[0001] The present invention relates to a lubrication system for dosing oil to one or more
lubrication points in large piston engine cylinders, primarily in naval engines, and
more specifically in the manner indicated in the introductory clause of claim 1.
[0002] For this purpose it has been customary to use so-called central lubrication devices,
each of which operates in connection with the lubrication points of one or more cylinders
by pressing out oil portions through respective connecting pipes to the various oiling
points at relevant moments of time. These moments or short time intervals are precisely
defined in relation to the movement of the engine piston in the cylinder, the oil
supply through a considered lubrication point ideally occurring exactly at the brief
time lapse where a set of associated piston rings on the piston passes the concerned
oiling point. The lubrication of the cylinder wall becomes ineffective, if the oil
is supplied at moments where the cylinder wall is not being swept by the piston rings
or special by oil scraping rings, respectively, exactly adjacent to the individual
concerned lubrication point.
[0003] Normally the central lubrication devices are controlled in synchronism with the revolutions
of the engine crankshaft and it is therefore relatively easy to adjust the device
for supplying the various portions of lubricating oil to the various oiling points
at reasonably relevant moments of time. However, it has proven to be difficult to
obtain an optimal lubrication, including a reasonably acute beginning and ending of
the lubricating impulses, whereby it is necessary for obtaining a good oil dosage
during the correct short time lapse to prolong the lubricating period beyond this
time lapse, which in turn causes a certain oil waste. The cause of this is the occurring
elasticity or accumulator effect, which occurs in the external tubings between the
lubrication device and the oiling points, this of course being most pronounced in
connection with the longest of these tubings. The pipes should be reasonably easy
to mount, and it is limited how sturdy and rigid they can be. Moreover, there will
be a certain elasticity also in the oil columns in the pipes.
[0004] However, from DK-C-81,275 a proposal is known, in which the central lubricating device
is replaced by or supplemented with dosing units which are placed immediately near
the individual oiling points or groups of these and thus are connected therewith through
relatively short pipes, these units acting as controlled closing valves between an
oil pressure pipe and the oiling points. The associated valve members are actuated
towards an open position by a spring or weight load, while they are electromagnetically
actuated towards a closed position, such that from a switch unit, which is actuated
in synchronism with the engine revolutions, they are operable automatically for opening
at just the correct moments and through time lapses of an appropriately short duration.
In the concerned publication it is mentioned that pure time control of corresponding
dosing valves has been tried, but that this does not ensure injection of a correct
oil quantity, and on this background it is proposed to use a combination of volumetric
dosing from the oil pump and a time control of the dosing valve. Hereby it will be
possible to obtain that the valve is brought to a sudden opening after the oil pump
having built up the high pressure at the oiling point despite the said springing effect
in the long connection pipe, as well as to a sudden closing before the same pressure
starts to drop at the end of the volumetric dosing from the pump. It is hereby possible,
in a desired manner, to maintain a high injection pressure during each individual
oiling sequence, but the total installation will be noticeably more expensive, and
it will be difficult to produce a fast, automatically controlled adjustment of the
effectively injected oil quantity depending on varying operational conditions. It
is even indicated in the said proposal that a pressure oil accumulator may advantageously
be used which is placed in immediate proximity to the inlet of the individual dosing
unit, such that it is possible by the relatively sudden opening of the valve to maintain
the desired high supply pressure of the oil in an extra safe manner. On the same background
it would almost amount to an advantage that a certain elasticity occurs in the longer
supply pipe for the pressure oil, also because on average there must be correspondence
between the oil supply from the oil pump and the inlet of oil at the oiling point.
[0005] In consonance with the prior art it is a basic consideration in connection with the
present invention that a primary aim is a lubrication with a determined oil quantity
per round, even though it may be relevant to regulate this quantity, such as it is
basically attempted by the use of the central lubricating devices, in which stroke
adjustable piston pumps are provided for pressing out the oil to the individual oiling
points or groups thereof. Only, in connection with the invention, it is realized that
this principle may very well be applied without the said associated problems by a
partial implementation of the known suggestion, viz. by the lubrication system being
embodied as indicated in the characterizing clause of claim 1, i.e. in principle by
effecting both the volumetric dosing and the time control by means of the locally
placed dosing units.
[0006] The dosing unit or units being designed for volumetrically determined intake and
outlet of the oil portions, the latter will or may be correct regardless of the operating
speed of the piston engine or the viscosity of the oil, and by the very fact of the
dosing being controllable, an adaptation may easily be effectuated according to occurring
parameter changes which may make such an adaptation desirable, e.g. a change of the
oil viscosity. The dosing units may be embodied in a very simple manner, e.g. as simple
cylinders with a piston or a piston plug which is displaceable between a fixed end
of the cylinder and an opposed end, in which is provided a stopper rod insertable
axially from the outside, which rod at the outside is in spindle-and-nut connection
with a driving station in the shape of a step motor, which, controlled by the control
unit, may quickly and easily direct the stopper rod into any relevant position with
a high accuracy. The pressurized oil may be used for filling the cylinder by its own
pressure until the piston abuts the axial stop, and thereafter the pressurized oil
may be used for emptying the measured-out oil volume to the oiling point, viz. in
being connected to the cylinder space at the opposite side of the piston. Thus, the
dosing will require no further operation energy, except for the valve control itself.
[0007] The dosing units may be single-acting, with a working space which may be connected
alternately to the inlet for pressurized oil, for filling of the working space, and
to the oiling point for supplying oil thereto, and with a pressure champer, which
is correspondingly alternately connectable to a return pipe and to the pressure oil
inlet respectively, such that the piston may press out the oil in this champer during
the filling of the working space and be pressed forwards by the pressurized oil for
pressing out the measured-out oil volume. By this embodiment it will be possible to
make use of a differential piston, one part of which operates in a pressure chamber
of increased diameter relative the working chamber, the space between this piston
and the narrower working piston simply being permanently connected to said return
pipe. Hereby the ordinary oil pressure may be used for providing a locally strongly
increased oiling pressure at the dosing unit.
[0008] The dosing units may also be double-acting, the cylinder chambers on the two sides
of the piston being connectable alternately to the pressure oil inlet and the oiling
point, respectively. By such an installation the said return pipe may be altogether
dispensable. Also by this arrangement there may be made use of a differential piston,
in double, even though a return pipe must then be used.
[0009] In the following the invention is explained in more detail with reference to the
drawing, in which
Fig. 1 is a schematic side view of a single cylinder of a naval diesel engine,
Fig. 2 is a more detailed sectional view of an individual oil injection unit used
in connection herewith, and
Fig. 3 is a corresponding sectional view of a modified embodiment of the injection
unit.
[0010] The cylinder shown in Fig. 1 has a cylinder liner 2 in which is provided a number
of oiling holes 4, each of which is connected through a short pipe 6 to an associated
injection respectively dosing unit 8. These units 8 are supplied with pressure oil
through supply pipes 10 from a high-pressure pump 12 suctioning from a tank 14, to
which is conducted a supply pipe 16 from a non-illustrated supply of lubricating oil,
and a return pipe 18 from the units 8. Electrical control cables are indicated in
dotted lines 20 from a control unit 22 to the individual units 8.
[0011] In the illustrated, normally preferred manner the cylinder is provided with a piston
24, which via a piston rod 26 and a connecting rod 28 is connected to a crank 30,32
in a crank housing. On the piston it is suggested that a pair of piston or scraping
rings 36 are placed near the top of the piston, and the ideal is that the lubricating
oil from each oiling point 4 be injected just when this pair of rings passes the concerned
oiling point, which means in practice that the injection of the lubricating oil should
take place by high power during a very short lapse of time.
[0012] The individual injection respectively dosing units in a preferred embodiment are
constructed as shown in Fig. 2. As a main part, each unit has a piston cylinder 40
with an outlet pipe 42 connected to a switch-over valve 44, which, controlled by an
actuator unit 46, may be switched to connection with the injector pipe 6 and the oil
supply pipe 10, respectively. The short pipe 6 is provided with a check-valve 7, preventing
backwards flow of oil from the oiling hole 4.
[0013] A piston 48 is mounted in the cylinder 40, and at its rear end the cylinder 40 is
connected to a pipe conduit 50 leading to a switch-over unit 52 which is co-operated
with the switch-over valve 44 in such a manner that the conduit 50 will be connected
to the oil pressure pipe 10 when the outlet pipe 42 is connected to the injector pipe
6, while the pipe conduit 50 will be connected to the return pipe 18, when the outlet
pipe 42 is connected to the pressure pipe 10.
[0014] Above the piston 48 is placed a stopper rod 54 projecting in through the upper rear
end of the cylinder 40, which rod determines the maximally retracted position of the
piston 48. In a manner not shown, this rod is secured against being rotated, and at
its outer end it is in thread engagement with a stationarily fixed nut 56, which may
be caused to rotate by a step motor 58 controlled from the control unit 22 in Fig.
1.
[0015] A pressure transducer 60 may be placed in connection with the pipe 50, and optionally
a corresponding transducer may be placed at the outlet 42,6 from the cylinder 40.
These transducers may be connected to the control unit 22 e.g. for control and supervision
purposes. In a preparatory phase the valve unit 44,52 is held in such a position in
which the pipe 42 is connected to the pressure pipe 10 at the lower end of the cylinder
40, while at the upper end of the cylinder the pipe 50 is connected to the return
pipe 18. Hereby pressurized oil will be injected into the lower end of the cylinder
40, such that the piston 48 is pressed upwards until it abuts the end of the stopper
rod 54. Thereby, an accurately determined volume of oil will be measured out in the
cylinder 40 below the piston 48, given by the positioning of the stopper rod 54, i.e.
by the signals received by the motor 58 from the control unit 22 through the cable
20. As shown by arrows in Fig. 1, the control unit 22 receives a plurality of different,
relevant informations from various sensors in the system, such that the oil volume
injected into the cylinder 40 will be appropriate for the subsequent supply of this
volume through the oiling hole 4.
[0016] Immediately before the passage of the pair of piston or scraper rings 36 past the
oiling hole 4, the control unit 22 will provide current to the activating unit 46
for switching the valve unit 44,52. This means that the lower end of the cylinder
is now connected to the oiling hole 4 through the pipe 6, and that the upper end of
this cylinder is connected to the pressure pipe 10 through the pipe 50, such that
high pressure oil is conveyed to the space above the piston 48. Thereby this piston
is thrust powerfully downwards so as to eject the oil portion in front of the piston
with great force in front of the piston for delivery through the oiling hole 4 during
a very brief time lapse, thus with an abrupt finishing of both the beginning and the
ending phase of the opening period.
[0017] Immediately thereafter the unit 46 may be activated for resetting the switch valve
44,52, such that once more a new oil portion may be filled into the upper space of
the cylinder 40. The filling will once more take place until the piston 48 abuts the
stopper rod 54, the position of which may be currently adjusted by the control of
the step motor 58 from the control unit 22, based on detections from different relevant
sensors. Thus, mechanically it will be completely uncomplicated to arrange the control
according to any desired criteria, inasfar as both the input and the relative or mutual
weighting of the criteria may take place in the control unit 22. For instance, a detected
reduced motor load may condition a reduced oil dosage, while at the same time, as
a primary function, it may be desirable to increase the dosing, if a sudden change
in the motor load has just occurred, also including a reduction hereof, as such changes
may otherwise cause an increased cylinder wear. The increased dosing should be maintained
through a certain period of time after the occurred change, e.g. 15-30 minutes, which
may easily be adjusted by means of a timer and optional sensors connected thereto
for detection of conditions which may influence the optimal length of the period through
which the increased lubrication is maintained. It is not the purpose of the invention
to indicate the concerned control parameters in more detail, but only to establish
that the dosing units are easily controllable according to all thinkable parameters,
when only the control unit 22 may convey the final result to the motor 58 or corresponding
adjustment means, respectively, and to the activation unit 46,54 for the individual
dosing units, regardless of the nature of this activation.
[0018] For obtaining that the dosings are accomplished with high force and speed, it may
be desirable in connection with the shown arrangement that a pressure oil accumulator
is placed in the inlet conduit 10 immediately in front of each of the switch-over
units 52 or in front of various local groups of dosing units, e.g. merely in the shape
of a slightly resilient container of a somewhat larger diameter that the inlet pipe
10, such that the required amount of oil may very quickly flow to the the rear end
of the cylinder 40 by the activation of the valve 44,52, not requiring the inlet pipe
10 to have any particularly large diameter.
[0019] In the embodiment of the dosing unit shown in fig. 3, the pressure oil in the inlet
10 is stille used for pressing forward the piston 48 for dosing oil from the measuring
chamber in front of the piston, but here the unit is designed as a double-acting unit.
In position I, the shown change-over valve 62 sends pressure oil from the pipe 10
into the right hand end of the cylinder 40 through a pipe 64, while the left hand
end of the cylinder is connected to a parallel change-over valve 66, position I, through
a pipe 68. This valve is permanently connected to the concerned lubrication point
or points through a short pipe 70.
[0020] As said, the pipes 64 and 68 are connected to the I-positions of the respective change-over
valves 62 and 66, but moreover, they are connected through pipe extensions 74 and
76 to the II-positions of the respective opposite change-over valves.
[0021] The cylinder 40 is entirely oil-filled at both sides of the piston 48. With the pair
62,66 of change-over valves in the shown position II, the piston 48 will be in the
illustrated end position to the right. When an oil portion is to be dispensed, the
valve 62,66 is changed into position I. Pressure oil from the pipe 10 will then flow
to the right end of the cylinder through the valve 62 and the pipe 64. The piston
48 is thereby displaced to the left and presses out oil through the pipe 68 to the
lubricating pipe 70. This pressing out abruptly stops, when the piston 48 abuts the
left end of the cylinder.
[0022] At the same time the expanded space to the right of the piston 48 will be filled
with oil, i.e. at the same occasion a new oil dose has been built up, the same quantity
of oil having flowed in as what has been pressed out at the other side of the piston.
[0023] Next time an oil portion is to be dispended, the valve 62,66 is again shifted to
position II. Pressure oil from the pipe 10 will then flow to the left end of the cylinder
through the valve 66 and the pipe 68. The piston 48 is thereby displaced to the right
and forces out the oil portion which was at the right side of the piston through the
pipe 64, the valve 62 and the pipe 74 to the lubrication pipe 70. This forcing abruptly
stops, when the piston 48 abuts the stopper rod 54.
[0024] The situation will now again be as shown in Fig. 3, i.e. new lubrication operations
may be effected as described.
[0025] A quite important advantage of using the system shown in Fig. 3 will be that the
entire installation may be arranged without any return pipes 18. The illustrated embodiments
are based on the successive dosings of previously measured-out volumes of lubricating
oil, but it will be appreciated that the invention is not limited thereto. Thus, the
control unit, given some extreme situation, may interfere with the dosing process
by shifting back the valve unit 44,46,52 already before the piston 48 has been pressed
entirely forwards in the cylinder 40. The connection conduits 6 between the dosing
units and the motor cylinder may be kept quite short, such that from a flow-technical
point of view they may appear entirely rigid and thus without any noticeable accumulator
effect, as would be undesired here. However, it will be appreciated that e.g. by horizontal
positioning of the cylinders 40, the dosing units will be placeable in direct connection
with the cylinder lining, integrated with the associated oiling holes 4, whereby a
possible accumulator effect may be suppressed. It is a further possibility that each
dosing unit may be arranged so as to operate in connection with several lubrication
points simultaneously, inasfar as normally several lubrication points are placed in
the same cross section of the engine cylinder. Furthermore, an individual dosing unit
will be able to operate in connection with several lubrication points at different
moments, viz. through a suitable shifter equipment.
[0026] It should be noted that the dosing units do not necessarily have to be placed immediately
next to the oiling points. Already the possibility of positioning right next to the
cylinder area will entail a noticeable reduction of the length of the lubrication
pipes relative to current practice, and optionally the units may then be placed in
local groups.
[0027] In connection with the discussed embodiments it is the pressure oil per se which
is used for producing the injection force, but the invention is not limited hereto.
Optionally a compressed-air system may be used, e.g. in connection with a differential
piston arrangement for amplifyring the pressure exerted on the dosing piston. Alternatively
a strong electromagnet may be used for projecting the dosing piston against a suitable
spring effect. In such cases the inlet oil does not have to be conveyed at any particularly
high pressure.
1. A lubrication system for successive dosing of oil to one or more lubrication points
in large piston engine cylinders, especially in naval motors, which installation comprises
an oil pump (12) and a dosing unit (8) connected to the pressure side thereof, optionally
several such units (8), which are preferably placed near the concerned lubrication
points, each dosing unit (8) being adapted so as to convey pressurized oil in an endeavoured
well-controlled amount to each connected oiling point by control from a control unit
(22) during predetermined short phases of the operative cycle of the piston engine,
optionally with supplements of oil from an oil accumulator in proximity of the dosing
unit, characterized in that the dosing unit (8) or each of these units is provided
as a volumetric measuring unit, which from the control unit (22) is operable for controlled
change of the measuring volume, and which is designed and arranged such that by a
subsequent controlled operation the measured-out amount of oil can be discharged to
the lubrication point or points under influence of a locally applied pressure force
on the said amount of oil, e.g. the oil pressure in the oil inlet pipe (10) itself
and an oil accumulator optionally placed therein.
2. A system according to claim 1, characterized in that the dosing unit (8) is provided
with a measuring cylinder (40) in which is mounted a piston (48) or a piston plug,
the mobility of which is limited, in at least one direction by a stop abutment (54),
the position of which is adjustable from the outside by means of a moving mechanism
such as a step motor (58) controllable by means of the control unit (22).
3. A system according to claim 1, characterized in that the dosing unit (8) is connected
to a pressure oil installation through associated individual control valves (44,52),
which from the control unit (22) are shiftable between a stand-by position in which
the pressure oil may flow to a measuring chamber in the individual units for filling
this chamber in the time lapse between the successive dispensings, and an lubricating
position in which the pressure oil is used as a means for forcing out the oil in the
measuring chamber to the respective oiling points.
4. A system according to claim 2, characrerized in that each of the opposed ends of the
measuring cylinder is in pipe connection with a change-over valve block, through which
blocks the respective opposed cylinder chambers at the opposed sides of the piston
(48) or piston plug are alternatingly connectable with a pressure oil inlet and an
outlet (42) connection to the lubrication point or points, respectively.
5. A system according to claim 1, characterized in that the control unit (22) for current
determination of the dispensing volume is of the type which is able to determine the
lubrication need from a plurality of measured parameters in the operation system.
6. A system according to claim 1, in which the controllable source of the locally applied
pressure is a strong electromagnet operable to actuate a piston for forcing out the
measured-out amount of oil.
1. Ein Schmiersystem für das sukzessive Dosieren von Öl an einen oder an mehrere Schmierstellen
in großen Kolbenmotorzylindern, besonders in Schiffsmotoren, wobei diese Vorrichtung
eine Ölpumpe (12) und eine Dosiereinheit (8), die mit der Hochdruckseite derselben
verbunden ist, und optional verschiedene solcher Einheiten (8), die vorzugsweise nahe
den betreffenden Schmierstellen angeordnet sind, umfaßt, wobei jede Dosiereinheit
(8) so angepaßt ist, um Drucköl in einer angestrebten, genau gesteuerten Menge an
jede Ölschmierstelle unter Steuerung von einer Steuereinheit (22) während vorbestimmter
kurzer Phasen im Betriebszyklus des Kolbenmotors zu liefern, wahlweise mit Ölzusätzen
von einem Ölakkumulator in der Nähe der Dosiereinheit, dadurch gekennzeichnet, daß
die Dosiereinheit (8) oder jede dieser Einheiten als eine Volumen-Meßeinheit vorgesehen
ist, die von der Steuereinheit (22) zum gesteuerten Wechseln des Meßvolumens betreibbar
und so gestaltet und angeordnet ist, daß bei einer nachfolgenden gesteuerten Operation
die abgemessene Öl-Menge an die Schmierstelle(n) unter dem Einfluß einer lokal auf
die Öl-Menge aufgebrachten Druckkraft abgegeben werden kann, z.B. dem Öldruck in der
Öl-Einlaßleitung (10) selbst und in einem darin optional angeordneten ölakkumulator.
2. Ein System nach Anspruch 1, dadurch gekennzeichnet, daß die Dosiereinheit (8) mit
einem Meßzylinder (40) versehen ist, in dem ein Kolben (48) oder ein Kolbenstopfen
angebracht ist, deren Beweglichkeit wenigstens in einer Richtung durch einen Anschlag
(54) begrenzt ist, dessen Position von außen durch Mittel eines Bewegungsmechanismus,
wie eines Schrittmotors (58), der mittels der Steuereinheit (22) steuerbar ist, einstellbar
ist.
3. Ein System nach Anspruch 1, dadurch gekennzeichnet, daß die Dosiereinheit (8) mit
einer Öldruckeinrichtung durch zugehörige einzelne Steuerventile (44, 52) verbunden
ist, die durch die Steuereinheit (22) zwischen einer Bereitschaftsstellung, in der
das Drucköl in der Zeit zwischen den sukzessiven Abgaben zu einer Meßkammer in den
einzelnen Einheiten zum Füllen dieser Kammer fließen kann, und einer Schmierstellung
geschaltet werden können, in der das Drucköl als Mittel zum Austreiben des Öls in
der Meßkammer zu den entsprechenden Schmierölpunkten benutzt wird.
4. Ein System nach Anspruch 2, dadurch gekennzeichnet, daß jedes der entgegengesetzten
Enden des Meßzylinders eine Rohrverbindung mit einem Umschalt-Ventilkopf aufweist,
durch den die entsprechenden entgegengesetzten Zylinderkammern an den entgegengesetzten
Seiten des Kolbens (48) oder Kolbenstopfens alternierend mit einer Drucköleinlaßbzw.
-auslaß-Verbindung (42) zu der Schmierstelle oder -punkten verbindbar sind.
5. Ein System nach Anspruch 1, dadurch gekennzeichnet, daß die Steuereinheit (22) zur
laufenden Bestimmung des abgegebenen Volumens der Art ist, die es gestattet, den Schmierölbedarf
aus einer Mehrzahl gemessener Parameter des Betriebssystems zu bestimmen.
6. Ein System nach Anspruch 1, bei dem die steuerbare Quelle des lokal aufgebrachten
Drucks ein starker Elektromagnet ist, der zum Bewegen eines Kolbens zum Austreiben
der abgemessenen Öl-Menge betreibbar ist.
1. Système de lubrification pour le dosage successif d'huile en un ou plusieurs points
de lubrification dans des grands cylindres de moteur à pistons, particulièrement dans
des moteurs marins, laquelle installation comprend une pompe à huile (12) et une unité
de dosage (8) reliée au côté refoulement de celle-ci, éventuellement plusieurs telles
unités (8), qui sont placées de préférence proches des points de lubrification concernés,
chaque unité de dosage (8) étant adaptée de façon à véhiculer l'huile sous pression
en une quantité bien contrôlée souhaitée à chaque point de lubrification relié par
commande à partir d'une unité de commande (22) pendant de courtes phases prédéterminées
du cycle de fonctionnement du moteur à pistons, éventuellement avec des compléments
d'huile à partir d'un accumulateur d'huile à proximité de l'unité de dosage,
caractérisé en ce que l'unité de dosage (8) ou chacune de ces unités est prévue comme
une unité de mesure volumétrique, à partir de laquelle l'unité de commande (22) est
apte à fonctionner pour le changement commandé du volume de mesure, et qui est conçue
et agencée de telle sorte que, par une opération commandé subséquente, la quantité
mesurée d'huile peut être évacuée vers le ou les points de lubrification sous l'influence
d'une force de pression appliquée localement sur ladite quantité d'huile, par exemple
la pression d'huile dans le conduit d'admission d'huile (10) lui-même, et un accumulateur
d'huile éventuellement disposé dans celui-ci.
2. Système selon la revendication 1,
caractérisé en ce que l'unité de dosage (8) est munie d'un cylindre de mesure (40)
dans lequel est monté un piston (48) ou un embout de piston, dont le déplacement est
limité, dans au moins un sens par une butée d'arrêt (54), dont la position est réglable
depuis l'extérieur par l'intermédiaire d'un mécanisme à déplacement tel qu'un moteur
pas à pas (58) commandable par l'intermédiaire de l'unité de commande (22).
3. Système selon la revendication 1,
caractérisé en ce que l'unité de dosage (8) est reliée à une installation d'huile
sous pression par des valves de commande individuelles associées (44,52), qui, à partir
de l'unité de commande (22), sont déplaçables entre une position d'attente dans laquelle
l'huile sous pression peut s'écouler vers une chambre de mesure dans les unités individuelles
pour remplir cette chambre dans le laps de temps entre les distributions successives,
et une position de lubrification dans laquelle l'huile sous pression est utilisée
comme moyen pour pousser l'huile dans la chambre de mesure vers les points de graissage
respectifs.
4. Système selon la revendication 2,
caractérisé en ce que chacune des extrémités opposées du cylindre de mesure est en
liaison par conduit avec un bloc de valves de commutation, à travers lesquels blocs,
les chambres de cylindre opposées respectives sur les côtés opposés du piston (48)
ou de l'embout de piston, sont alternativement reliées à une entrée d'huile sous pression
et à une liaison de sortie (42) au point ou aux points de lubrification, respectivement.
5. Système selon la revendication 1,
caractérisé en ce que l'unité de commande (22) pour la détermination en cours du volume
de distribution est du type qui est capable de déterminer le besoin de lubrification
à partir d'une pluralité de paramètres mesurés dans le système de fonctionnement.
6. Système selon la revendication 1,
dans lequel la source commandable de la pression appliquée localement est un électro-aimant
puissant capable d'actionner un piston pour pousser la quantité d'huile mesurée vers
l'extérieur.