EP2177720B1 - Large diesel engine - Google Patents

Description

The invention relates to a large diesel engine according to the preamble of the independent claim.

Large diesel engines, which may be designed as two-stroke or four-stroke engines, are often used as power units for ships or even in stationary operation, e.g. used to drive large generators for generating electrical energy. The engines usually run for long periods in continuous operation, which places high demands on the reliability and availability. Therefore, for the operator in particular long maintenance intervals, low wear and an economical handling of the operating materials are central criteria.

Of major importance is the cylinder or the piston lubrication. In the operating state, the piston slides on the inner wall of the cylinder serving as a running surface, which is usually designed in the form of a cylinder liner. On the one hand, the piston must slide as easily as possible, that is, unhindered, in the cylinder, on the other hand, the piston must the combustion chamber in the cylinder as well as possible seal to ensure efficient conversion of energy released during the combustion process into mechanical work.

Therefore, during operation of the diesel engine, a lubricating oil is usually introduced into the cylinder in order to achieve good running properties of the piston and to minimize the wear of the cylinder wall, the piston and the piston rings. Furthermore, the lubricating oil is used to neutralize aggressive combustion products and to prevent corrosion. Due to these numerous requirements, lubricating oils are often used very high quality and expensive substances.

Today, lubrication systems used in large diesel engines deliver the lubricant, usually a lubricating oil, through the wall of the cylinder to the tread or directly into the piston ring package of the piston so that the piston rings distribute the lubricant on the tread during their movement. The introduction of the lubricant takes place through lubrication points, which typically form the outlet openings of nozzles, lubricating nozzles or so-called quills.

For the supply of the individual lubrication points usually a lubricating oil pump per cylinder is used, which supplies all lubrication points of this cylinder with lubricant. Due to the design, this lubricating oil pump may be a few meters away from the respective cylinder or from the respective lubrication points.

The problem with known systems is that the desired injection precision, if at all, can only be ensured with great difficulty.

If, for example, the lubricant is to be introduced into the piston ring package, so depending on the position of the lubrication points at full speed of the engine only a few milliseconds available during which the piston ring package passes the lubrication points. Due to system inertia, the For example, due to the compressibility of the lubricant or due to the hydraulic inertia, the lubricating oil pump to compensate must have a lead time, which must be laboriously determined and adjusted.

Depending on the wear in the system or depending on the operating conditions, this required lead time may change and must therefore be monitored, compared with the effective time of introduction and corrected if necessary.

Despite such measures, severe inaccuracies in the effective time of introduction of the lubricant may still be adversely affected by, for example, the significant differences in the respective distances between the lubrication point and the lubricant pump supplying it, as these differences result, inter alia, in different hydraulic inertias and differences in the compressibility of each moving lubricant.

Based on this prior art, it is therefore an object of the invention to provide a large diesel engine with a lubrication system that allows the most efficient and flexible cylinder or piston lubrication, in which the timing of the introduction of the lubricant can be adjusted very accurately in a simple manner

The problem-solving object of the invention is characterized by the features of the independent claim.

According to the invention, therefore, a large diesel engine is proposed with at least one cylinder which has a bore and a longitudinal axis, and in which a piston can be moved back and forth along a running surface is arranged, wherein a lubrication system for the cylinder lubrication is provided, which comprises at least two lubrication points, via which a lubricant can be applied to the tread, and a lubricant supply for conveying the lubricant from a lubricant reservoir to the lubrication points. The lubricant supply has at least one pump-nozzle unit, which is arranged at the lubrication points, each pump-nozzle unit comprising a pump which is connected to the highest two lubrication points, so that each unit injector with lubricant at most two lubrication points provided.

Since the pump-nozzle unit is provided directly at the lubrication points, in particular such that the lubrication point forms the outlet opening of the nozzle, results in a very short distance between the pump and the lubrication point supplied by them. Thus, the problems caused by long lines, which are based in particular on the hydraulic inertia and the compressibility of the lubricant, at least greatly reduced, so that a high accuracy with respect to the timing of the introduction of the lubricant is made possible.

Preferably, the pump of each unit injector is operable independently of the pumps of the other unit injectors. Characterized in that for each one or at most two lubrication points, an independently operable pump is provided, also results in a very flexible and efficient cylinder lubrication, which can be adapted in particular in a simple manner to the respective operating state of the large diesel engine.

With regard to the highest possible registration accuracy for the lubricant, it is preferred if the distance between the outlet of the pump of the pump-nozzle unit and each lubrication point connected to it is each is at most as large as the diameter of the bore of the cylinder.

In a preferred embodiment, each pump-nozzle unit comprises at least one nozzle which connects the outlet of the pump to one of the lubrication points, each nozzle being at most as long as the diameter of the bore of the cylinder.

In a preferred embodiment, exactly one, preferably independently operable, pump-nozzle unit is provided for each lubrication point, so that each lubrication point can be controlled individually and timely. This allows a very high degree of flexibility with regard to the cylinder lubrication to be realized.

In another preferred embodiment, at least one pump-nozzle unit is provided, which is connected to two lubrication points, and which is arranged so that the distance from the outlet of the pump to the lubrication point for both lubrication points is the same size. The design with two lubrication points per unit injector reduces the expenditure on equipment. The fact that the lubrication points have the same distance from the pump-nozzle unit, so in particular are arranged symmetrically with respect to the pump-nozzle unit, all problems can be avoided, which eliminate different lengths of cable between the lubrication points and the pump supplying them.

Since it is structurally very simple, there is a preferred embodiment in that the pump of the pump-nozzle unit is designed in each case as a piston pump, in which a working piston is arranged to move back and forth in a pump chamber and at each stroke a flow of lubricant through conveys the outlet of the pump into the nozzle.

A variant is that the pump of the pump-nozzle unit comprises a plurality of working pistons, each of which is arranged in a separate pumping space. With this measure, for example, the flow rate of lubricant, which is promoted per stroke to the lubrication point or to the lubrication points, can be adjusted in a simple manner. Thus, with less lubricant requirement, e.g. in part-load operation, only one working piston are actuated and with higher lubricant requirement, two or more working pistons are actuated.

In particular, in embodiments in which the working piston of the pump-nozzle unit is operated with a constant delivery volume, it is advantageous if the working piston and the associated pumping chambers of a pump-nozzle unit are designed for different flow rates. Thus, with reduced lubricant requirement, a working piston with a smaller flow rate per stroke can be actuated, while with increased lubricant requirement, a working piston with a larger flow rate per stroke and / or several working pistons are actuated.

Preferably, the pump of the pump-nozzle unit is hydraulically or pneumatically or hydraulically / pneumatically actuated.

Of course, it may also be advantageous if the pump of the pump-nozzle unit is electrically actuated.

In a preferred embodiment, the lubrication system includes a common rail accumulator for the lubricant, which is connected to all lubricant supply lines.

With regard to a particularly efficient and flexible lubrication in the cylinder, it may be advantageous if the lubrication points with respect to by the Longitudinal axis of the cylinder fixed axial direction are arranged at different positions. Thus, namely, the lubricant can be introduced at different heights in the cylinder.

It may also be advantageous if at least two lubricant reservoirs are provided for different lubricants, so that different lubricants can be fed to the lubrication points. Since more than two lubrication points are generally provided in the case of the large diesel engine, the design of the lubrication system according to the invention makes it possible to introduce at least two different lubricants into the cylinder. For example, in the vicinity of the combustion chamber, a lubricant can be used, which is particularly favorable with regard to the neutralization of aggressive combustion products, while further away from the combustion chamber, a lubricant is used, which is particularly favorable in terms of sliding properties. It is also possible, depending on the operating condition of the engine, e.g. Part load or full load to use different lubricants for cylinder lubrication.

Furthermore, it is a preferred measure if means are provided to set the amount of lubricant delivered by the pump-nozzle unit to a predefinable value. Thus, the cylinder lubrication can be adapted to the respective operating conditions.

Further advantageous measures and preferred embodiments of the invention will become apparent from the dependent claims.

Fig. 1:

eine schematische Darstellung eines ersten Ausführungsbeispiels eines erfindungsgemässen Grossdieselmotors,

Fig. 2:

eine schematische Schnittdarstellung durch einen Zylinder des ersten Ausführungsbeispiels,

Fig. 3:

eine Pumpe-Düse-Einheit eines zweiten Ausführungsbeispiels eines erfindungsgemässen Grossdieselmotors,

Fig. 4:

ein Variante für die Anordnung der Schmierstellen, und

Fig. 5:

eine schematische Darstellung für eine Variante der Pumpe-Düse-Einheit.

In the following the invention will be explained in more detail by means of embodiments and with reference to the drawing. In the schematic, not to scale drawing show partly in section:

Fig. 1:

a schematic representation of a first embodiment of an inventive large diesel engine,

Fig. 2:

a schematic sectional view through a cylinder of the first embodiment,

3:

a pump-nozzle unit of a second embodiment of a large diesel engine according to the invention,

4:

a variant for the arrangement of the lubrication points, and

Fig. 5:

a schematic representation of a variant of the pump-nozzle unit.

Fig. 1 illustrates a schematic representation of a first embodiment of an inventive large diesel engine, which is generally designated by the reference numeral 1, and which may be designed as a two-stroke or four-stroke engine. Fig. 2 shows a schematic sectional view through one of the usually several cylinders 2 of the large diesel engine 1 from Fig. 1 , The cylinder 2 has a bore whose diameter is designated B, and a longitudinal axis A. The section in Fig. 2 is perpendicular to the longitudinal axis A of the cylinder. 2

In the cylinder 2, a piston 3 is arranged in a manner known per se to move back and forth, which moves in the operating state of the large diesel engine 1 along a running surface 21 on the inner wall of the cylinder 2. Usually, the tread 21 is formed by a cylinder insert or a liner. The piston 3 defines with its upper end according to the illustration a combustion chamber 4 in which the combustion process takes place, and usually has a plurality of piston rings, which are collectively referred to as the piston ring package 31.

During operation of the large diesel engine 1, it is necessary to apply a lubricant, for example a lubricating oil, to the running surface 21, which lubricates the piston 3, the piston ring pack 31 and the running surface in order to achieve good running properties of the piston 3 and the wear of the cylinder wall, to keep the piston 3 and the piston ring package 31 as low as possible. Furthermore, the lubricant is used to neutralize aggressive combustion products and to prevent corrosion, such as sulfur corrosion.

For the cylinder or piston lubrication, a lubrication system 5 is provided which comprises a plurality of lubrication points 6 via which the lubricant can be applied to the running surface 21. In the first embodiment, a total of eight lubrication points 6 are provided (see Fig. 2 ), which are arranged along the circumference of the cylinder 2. The lubrication points 6 each form the outlet opening of a nozzle 71, through which the lubricant is introduced into the cylinder 2. In the context of this application, the term "nozzle" means all devices suitable for introducing the lubricant; these may be, for example, nozzles in the strict sense, through which the lubricant is injected or atomized as a concentrated jet, or channels or nozzles, for example, referred to as quills, through which the lubricant runs out or drips, or any other devices that are known for introducing the lubricant into the cylinder 2 of a large diesel engine 1.

Further, a lubricant supply 8 is provided to promote the lubricant from a lubricant reservoir 10 to the lubrication points 6. In this embodiment, the lubricant reservoir 10 is a common rail memory or accumulator configured, which contains the lubricant under sufficient pressure, so that it can flow from the memory or accumulator to the lubrication points 6. Typically, the lubricant is provided by the common rail reservoir at a pressure of 1 to 20 bar. Alternatively, it is of course also possible that a pump, not shown, promotes the lubricant from a reservoir, or that the lubricant is in a high tank as a lubricant reservoir from which the lubricant can flow out due to gravity.

According to the invention, the lubricant supply 8 comprises at least one pump-nozzle unit 7, which is integrated at the lubrication points 6 in the lubricating oil supply 8, wherein each pump-nozzle unit 7 comprises a pump 72 which is connected to at most two lubrication points 6, so that each Pump-nozzle unit supplies at most two lubrication points 6. In the first embodiment, each pump 72 is operable independently of the pumps of all the other pump-nozzle units 7.

In the first embodiment is - like this Fig. 2 shows - for each lubrication point 6 exactly one independently operable pump-nozzle unit 7 is provided and each pump-nozzle unit 7 supplies exactly one lubrication point 6, so that the number of pump-nozzle units 7 is the same size as the number of lubrication points ,

The integrated in the lubricating oil supply 8 pump-nozzle units 7 are each arranged directly on the lubrication point 6, for example, mounted on the outer wall of the cylinder 2, so that a very short distance between the respective pump 72 and the lubrication point 6 supplied by her results. Since the nozzle 71, the outlet opening of which forms the respective lubrication point 6, together with the respective pump 72 forms a pump-nozzle unit 7, there are no connecting lines between the pump 72 and the nozzle 71 available. This results in the lubrication a much shorter reaction time, which increases the precision of the lubricant entry enormously.

Preferably, the distance D ( Fig. 2 ) between the outlet of the pump 72 of the pump-nozzle unit 7 and the lubrication point 6 connected to this pump 72 is at most as large as the diameter B of the bore of the cylinder 2. In particular, the length of the nozzle 71 of the pump-nozzle Unit 7, which connects the output of the pump 72 with the lubrication point 6, preferably at most as large as the diameter of the bore of the cylinder. 2

In the nozzle 71, a check valve 73 is provided in each case (in Fig. 2 not shown) to prevent backflow of the lubricant from the lubrication point 6 to the pump 72.

The pump 72 of the pump-nozzle unit 7 is designed as a piston pump, in which a working piston 74 is arranged in a pump chamber 75 movable back and forth. At each stroke of the working piston 74, a delivery of lubricant through the outlet of the pump 72 is fed into the nozzle 71.

For actuating the working piston 74 of the pump 72, a switching member 9 is provided, which in the in Fig. 1 illustrated embodiment is an electrically controlled 3/2-way valve. The switching member 9 connects in its first switching position, the back of the working piston 74 with an activation medium, such as hydraulic fluid, pressure oil or compressed air, which is available in a pressure accumulator 11. In the second switching position, the in Fig. 1 is shown, the switching member 9 connects the back of the working piston 74 with an outlet conduit 103, through which The activation medium from the back of the working piston 74 can flow out of the pump 72. The switching member 9 further includes an electromagnet 91 to move the switching member 9 against the force of a spring 92 from the second to the first switching position.

The control of the electromagnet 91 for Betätigiung the switching element 9 is effected by a control unit 12 which is connected via a signal line 200 shown in dashed lines with the switching member 9.

The control unit 12 has an automatic controller input 13 and a manual regulator input 14, which are each signal-connected to the control unit 12 (dashed arrows 201 and 202 in FIG Fig. 1 ). The automatic controller input 13 receives, preferably in real time, automatically input signals which contain information about the current operating state, such as speed or load of the engine, or other system parameters, such as position or position of the crankshaft. On the basis of these input signals, the times and, if appropriate, the quantities and the lubrication points 6 to be activated for the lubricant entry onto the running surface 21 are determined. By means of the manual controller input 14, parameters or specifications can be transmitted to the control unit 12 by hand.

In operation, the lubrication system 5 operates as follows: As long as no lubricant is to be applied to the tread 21, the lubrication system 5 is in the in Fig. 1 illustrated state. The switching element 9 is in the switching position in which the back of the working piston 74 is connected to the outlet line 103 for the activation medium. The pump chamber 75 is connected via a line 100 to the lubricant reservoir 10, wherein in the conduit 100, a check valve 76 is provided, which prevents backflow of the lubricant from the pump chamber 75 into the lubricant reservoir 10. In the lubricant reservoir 10 is the Lubricant stored under a slight overpressure of, for example, 0.2 bar to 1 bar above normal pressure sufficient to open the check valve 76, but not the check valve 73 in the nozzle 71. Thus, the pump chamber 75 fills completely with lubricant and the piston 74 runs in the illustration according to the left reversal point or stop. Optionally, it may be advantageous to additionally load the working piston 74 with a spring, not shown, which biases it into this position shown.

To trigger a lubrication process, the control unit 12 via the signal line 200 is a control pulse, so that the solenoid brings the switching element in the other switching position. Now, the back of the working piston 74 is connected to the pressure accumulator for the activation medium. The activation medium flows from the pressure accumulator 11 via connecting lines 102 and 101 against the back of the working piston 74 and moves it to the right until it reaches its right reversal point or stop according to the illustration. As a result of this movement of the working piston 74, the lubricant in the pump chamber 75 is pushed out through the nozzle 71 and reaches the running surface 21 in the cylinder 2 via the lubricating point 6.

Subsequently, the control unit 12 is activated by the spring 92, the switching element 9 back into the in Fig. 1 shown switching position, whereby the activation medium flows from the back of the Arbeistkolbens 74 in the outlet line 103, whereby the working piston 74 moves again in its representation according to the left reversal point and the pump chamber 75 is filled via the line 100 again with lubricant.

If the activation medium is compressed air, it can simply be blown off through the outlet line 103. If the activation medium is on Pressure oil or hydraulic fluid, it can be discharged via the outlet line 103 as return and then the pressure accumulator 11, which is configured for example as a common rail memory, are supplied.

In addition to the aforementioned hydraulic or pneumatic actuation of the pump 72, a combined pneumatic / hydraulic actuation can also be realized.

A direct electrical actuation of the pump 72 is possible, in which the working piston 74 directly by means of electromagnetic forces by coils and / or by otherwise electrically activated signal or pulse generator, for. B. piezocrystal activated, is moved back and forth.

The fact that the lubricant from the pump 72 passes directly into the nozzle 71 and thus to the lubrication point 6, the reaction times are extremely short compared to known lubrication systems in the large diesel engine. Both the hydraulic inertia and the compressibility of the lubricant between the pump 72 and the lubrication point 6 virtually eliminate any delay effects, resulting in a very high degree of precision in the timing of the lubrication. As a result, lubrication operations or positioning of the lubrication points 6 at such locations are possible or better realized, in which the piston 3 has a high speed, so that only a few milliseconds per working cycle are available for lubrication.

Since each pump-nozzle unit 7 is operable independently of the other pump-nozzle units 7, a very large flexibility and efficiency of lubrication can be realized. So it is possible, for example, with a reduced lubricant requirement not all eight of in Fig. 2 used lubrication points 6 but only four, for example to actuate the pump-nozzle units 7 so that only four of the total of eight lubrication points 6 lubricant is applied to the tread 21.

There are also such embodiments possible in which the switching member 9 actuates a plurality of pumps 72 different pump-nozzle units 7. For example, it is possible to provide exactly one switching element 9 per cylinder 2 in that all pumps 72 of this cylinder 2 are actuated. By this measure, the apparatus and the cost is reduced.

The introduction of the lubricant can be carried out so that each pump 72 of the pump-nozzle units 7 is operated at a constant delivery volume, i. with each activation or actuation of the working piston 74, the entire volume of the pumping space 75 is in each case conveyed into the nozzle 71.

Embodiments are also possible in which a stroke-controlled delivery is provided. In this case, the switching member 9 is timed so that the working piston 74 promotes only a portion of the lubricant in the pump chamber 75 in the nozzle 71. The back of the working piston 74 is relieved of pressure before the working piston 74 his in Fig. 1 has reached the illustration right extreme position. As a result, the delivery process is terminated, the working piston 74 moves as shown to the left and via the line 100 lubricant flows from the lubricant reservoir 10 into the pump chamber 75th

In the stroke-controlled promotion, it may be advantageous to provide a sensor with which the respective position of the working piston 74 can be detected. This position is then supplied to the control unit 12.

Fig. 3 shows the pump-nozzle unit 7 of a second embodiment of a large diesel engine according to the invention 1. From the function of equal or equivalent parts are provided with the same reference numerals as in Fig. 1 respectively. Fig. 2 ,

All explanations related to Fig. 1 . Fig. 2 and the first embodiment, apply in an analogous or analogous manner also for the second embodiment.

In this embodiment, the pump-nozzle unit 7 is connected to two lubrication points 6. Preferably, the pump-nozzle unit 7 is arranged so that the distance from the output of the pump 72 to the lubrication point 6 for both lubrication points 6 is equal.

The nozzle 71 is here designed as a forked nozzle 71, which splits into the two arms 71 a and 71 b, each of which leads to a lubrication point 6. The symmetrical design of the nozzle 71 ensures that the supply of both lubrication points takes place completely simultaneously. Preferably, the length of the nozzle 71 measured either over the arm 71 a or over the arm 71 b at most as large as the diameter B of the bore of the cylinder. 2

Of course, it is also possible to provide two nozzles instead of the forked nozzle 71, both of which open into the pumping space 75 of the pump 72 and the outlet of the pump 72 and which lead from there to one of the two lubrication points 6.

Fig. 4 shows a variant of the arrangement of the lubrication points 6, which is possible for both the first and the second embodiment.

In this variant, the lubrication points 6 'and 6 "are arranged at different positions with respect to the axial direction defined by the longitudinal axis A of the cylinder 2. The lubrication point 6' is arranged further down as shown, while the lubrication point 6" according to the illustration above, ie closer to Combustion chamber 4 is arranged.

In particular, in this variant, it is also possible to provide at least two lubricant reservoirs 10 for different lubricants, so that different lubricants can be supplied to the lubrication points 6 'and 6 "Thus, for example, a lubricant can be used in the vicinity of the combustion chamber 4 through the lubrication point 6", which is particularly favorable in terms of the neutralization of aggressive combustion products, while further away from the combustion chamber 4 through the lubrication point 6 ', a lubricant is used, that in terms of sliding properties is particularly favorable. It is also possible, depending on the operating condition of the engine, e.g. Part load or full load to use different lubricants for cylinder lubrication.

Deviating from the illustration in Fig. 4 For example, the two lubrication points 6 'and 6 ", which are arranged at different axial height, can also be supplied by the same pump-nozzle unit 7, namely in the same way as in FIG Fig. 3 is shown.

Fig. 5 shows a schematic representation of a variant for the pump-nozzle unit 7, which is possible for both the first and the second embodiment.

In this variant, the pump-nozzle unit 7 comprises a plurality, here namely three working pistons 741, 742 and 743, each of which is arranged in a separate pumping space 751, 752 and 753, respectively. For every working piston is a Switching member 9 ', 9 ", or 9"' provided to actuate the respective working piston 741, 742, and 743 in a manner analogous to the way already described above. This variant, in addition to the already mentioned stroke-controlled promotion is a means to adjust the amount of lubricant delivered by the pump-nozzle unit 7 to a predefinable value, namely by only one or two or all three of the working piston 741, 742, per lubrication 743 is actuated.

The pumping spaces 751, 752, 753 may have the same or different volume. At the in Fig. 5 1, the pumping space 751 has the smallest volume, the pumping space 752 has the second largest volume, and the pumping space 753 has the largest volume. Accordingly, at a constant delivery at which the pumping space 751, 752, 753 is completely emptied completely by the working piston 741, 742, 743, the delivery rate per working cycle will be smallest, if only the working piston 741 is actuated. If only one working piston 741, 742, 743 is actuated in each case, the delivery rate is greatest when the working piston 743 is actuated.

Of course, it is also possible to operate two or all three of the working pistons 741, 742 and 743 together. Also in this way, the respectively delivered amount of lubricant in a simple manner and optimally adaptable to the respective operating state of the large diesel engine 1.

It is understood that in Fig. 5 illustrated variant is also operable with a stroke-controlled promotion.

Notwithstanding the embodiments described here, it is also possible to provide the lubrication points in the piston 3 of the large diesel engine 1, so that the lubricant from the piston 3 out on the Tread 21 is applied. Preferably, then the pump-nozzle units 7 are also arranged in the piston 3 or in the piston rod. Of course, embodiments are possible in which lubrication points 6 are provided both in the piston 3 and in the cylinder 2.

Claims (15)

1. A large diesel engine having at least one cylinder (2) which has a bore (B) and a longitudinal axis (A) and in which a piston (3) is arranged movable to and fro along a running surface (21), wherein a lubrication system (5) Is provided for the cylinder lubrication which includes at least two lubrication points (6) via which a lubricant can be applied to the running surface (21) as well as a lubricant feed (8) for the conveying of the lubricant from a lubricant store (10) to the lubrication points (6), characterized In that the lubricant feed (8) has at least one pump-nozzle unit (7) which is arranged at the lubrication points (6), with each pump-nozzle unit (7) including a pump (72) which is connected to at most two lubrication points (6) so that each pump-nozzle unit (7) supplies at most two lubrication points (6) with lubricant.
2. A large diesel engine in accordance with claim 1, wherein the pump (72) of each pump-nozzle unit (7) can be actuated independently of the pumps (72) of the other pump-nozzle units (7).
3. A large diesel engine in accordance with claim 1 or claim 2, wherein the spacing (D) between the output of the pump (72) of the pump-nozzle unit (7) and each lubrication point (6) connected to it is In each case at most as large as the diameter (B) of the bore of the cylinder (2).
4. A large diesel engine in accordance with any one of the preceding claims, wherein each pump-nozzle unit (7) includes at least one nozzle (71) which connects the output of the pump (72) to one of the lubrication points (6); and wherein each nozzle (72) is at most as long as the diameter (B) of the bore of the cylinder (2).
5. A large diesel engine in accordance with any one of the preceding claims, wherein precisely one pump-nozzle unit (7), preferably actuable independently, is provided for each lubrication point (6).
6. A large diesel engine in accordance with any one of the claims 1 to 4, wherein at least one pump-nozzle unit (7) is provided which is connected to two lubrication points (6) and which is arranged such that the spacing from the output of the pump (72) to the lubrication point (6) is of equal size for both lubrication points (6).
7. A large diesel engine in accordance with any one of the preceding claims, in which the pump (72) of the pump-nozzle unit (7) is in each case made as a piston pump In which a working piston (74) is arranged movable to and fro in a pump space (75) and a conveyed quantity of lubricant is conveyed through the output of the pump (72) into the nozzle (71) on each stroke.
8. A large diesel engine in accordance with claim 7, In which the pump (72) of the pump-nozzle unit (7) includes a plurality of working pistons (741, 742, 743) of which each is arranged in a separate pump space (751, 752, 753).
9. A large diesel engine in accordance with claim 8, wherein the working pistons (741, 742, 743) and the associated pump spaces (751, 752, 753) of a pump-nozzle unit (7) are designed for different conveyed quantities.
10. A large diesel engine in accordance with any one of the preceding claims, in which the pump (72) of the pump-nozzle unit '(7) can be actuated hydraulically or pneumatically or hydraulically/pneumatically.
11. A large diesel engine in accordance with any one of the preceding claims, in which the pump (72) of the pump-nozzle unit (7) is electrically actuable.
12. A large diesel engine In accordance with any one of the preceding claims, in which the lubrication system (5) includes a common-rail store (10) for the lubricant which is connected to all lubricant feeds (8).
13. A large diesel engine in accordance with any one of the preceding claims, in which the lubrication points (6, 6', 6") are arranged at different positions with respect to the axial direction defined by the longitudinal axis (A) of the cylinder (2).
14. A large diesel engine in accordance with any one of the preceding claims, in which at least two lubrication stores for different lubricants are provided so that different lubricants can be supplied to the lubrication points (6, 6', 6").
15. A large diesel engine In accordance with any one of the preceding claims, wherein means are provided to set the quantity of lubricant conveyed by the pump-nozzle unit (7) to a presettable value.

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