DK181438B1

DK181438B1 - Large turbocharged two-stroke internal combustion engine with improved piston cooling

Info

Publication number: DK181438B1
Application number: DKPA202270305A
Authority: DK
Inventors: Moreno Blazquez Javier
Original assignee: Man Energy Solutions Filial Af Man Energy Solutions Se Tyskland
Priority date: 2022-06-10
Filing date: 2022-06-10
Publication date: 2024-01-09
Also published as: CN117211951A; KR20230171389A; JP2023181120A; DK202270305A1

Abstract

A large turbocharged two-stroke uniflow internal combustion engine (100) of the crosshead type with a telescopic pipe (30) mechanically connected to the cylinder frame (23) and the crosshead (9) and fluidically connecting to a source of pressurized lubrication and cooling medium to a conduit (36) in the crosshead (9), piston rod (15) and piston (10) for cooling the piston (10).

Description

DK 181438 B1 1

LARGE TURBOCHARGED TWO-STROKE INTERNAL COMBUSTION ENGINE WITH

IMPROVED PISTON COOLING

TECHNICAL FIELD

The present disclosure relates a large turbocharged two-stroke internal combustion engine of the cross-head type comprising at least one cylinder in which is received a reciprocating piston that is cooled by a flow of cooling medium supplied to the piston via a telescopic pipe that connects the cylinder frame to the crosshead.

BACKGROUND

Large turbocharged two-stroke internal combustion engines are typically used in propulsion systems of large ships or as a prime mover in power plants. Their sheer size, weight, and power output render them completely different from common combustion engines and place large two-stroke turbocharged compression- ignited internal combustion engines in a class for themselves.

The height of these engines is typically not crucial, and therefore they are constructed with crossheads in order to avoid lateral loads on the pistons. Typically, these engines are operated with natural gas, petroleum gas, methanol, ethane, or fuel oil.

Large turbocharged two-stroke internal combustion engines can be operated with compression ignition, i.e. according to the

Diesel principle, or as a premix engine, i.e. according to the

Otto principle, in which the scavenging gas is mixed with fuel during the stroke of the piston from bottom dead center (BDC) to top dead center (TDC).

The piston is typically made of heat-resistant steel to ensure that it can withstand the high temperatures in the combustion chamber. Further, the piston is cooled by a cooling medium, e.g.

DK 181438 B1 2 lubrication oil to prevent the piston from overheating during engine operation.

The engine lubrication system provides various components of the engine with a lubrication medium. The lubrication medium is also used for cooling the piston. Typically, the medium used is lubrication oil.

A branch of the lubrication system is connected by a telescopic pipe to the crosshead from where the lubrication and cooling medium has several functions, including traveling up the piston rod to cool the piston and then down again and lubricating the crosshead bearing and the guide shoes that guide the crosshead between vertical guide plates. One part of the telescopic pipe is connected to the crosshead and another part of the telescopic pipe is connected to the cylinder frame or tothe inlet manifold, crossing the cylinder frame, whereby the lumen of the telescopic pipe is used to transport the cooling medium from a connection point at the cylinder frame via the cross-head and a conduit in the piston rod to the piston. The telescopic pipe comprises an outer pipe with an inner pipe at least partially received in the lumen of the outer pipe. The inner pipe can move translationally to follow the reciprocating movement of the crosshead relative to the cylinder frame.

JPS57176616U discloses a large turbocharged two-stroke uniflow internal combustion engine of the crosshead type according to the preamble of claim 1.

SUMMARY

It is an object of the invention to provide a large turbocharged two-stroke uniflow internal combustion engine of the crosshead type with improved piston cooling.

DK 181438 B1 3

Tests and simulations carried out by the inventor revealed that the cooling of the piston fluctuates significantly during an engine cycle and that a major portion of the cooling occurs during a relatively small portion of the engine cycle. Through further tests and simulations, the inventors arrived at the insight that the fluctuations are caused by pressure and flow fluctuations of the cooling medium to the piston. Further analysis and insight revealed that these pressure and flow fluctuations are caused by the extension and retraction of the telescopic pipe during an engine cycle.

According to a first aspect, there is provided a large turbocharged two-stroke uniflow internal combustion engine of the crosshead type, the engine comprising: at least one cylinder liner with scavenge ports at its lower end and an exhaust valve at its upper end, a reciprocating piston in the at least one cylinder liner, the reciprocating piston being connected to a reciprocating crosshead by a piston rod, a source of pressurized and cooling and lubrication medium, a telescopic pipe fluidically connecting the source to an inlet port on the crosshead, a conduit extending from the inlet port to the piston, the conduit preferably extending through the crosshead and through the piston rod, and a valve configured to allow flow of cooling and lubrication medium from the source to the telescopic pipe and prevent or restrict flow of the cooling and lubrication medium from the telescopic pipe to the source,

DK 181438 B1 4 comprising a movable valve member that is arranged to be movable between a closed or restricted position on a first seat and an open position on a second seat and the movable valve member being biased to the open position by gravity only.

By providing a nonreturn valve or a valve that acts like a nonreturn valve upstream of the telescopic pipe or at the inlet of the telescopic pipe, reversed flow of the cooling medium during the compression stroke of the piston (from BDC to TDC), i.e. when the telescopic pipe contracts, can be avoided or at least reduced, thereby ensuring a more constant flow of cooling medium to the piston throughout an engine cycle. The inventor arrived at the insight that the closing of the nonreturn valve or the restriction to the valve ensures an increased flow of cooling medium since the telescopic pipe acts as a positive displacement pump when the telescopic pipe 1s contracting (compression stroke of piston) if return flow from the telescopic pipe to the source his prevented or restricted. The resulting substantially increased flow of cooling medium throughout an engine cycle improves piston cooling through an increase in cooling capacity, by extending the duration of active cooling, the valve comprises a movable valve member that is arranged to be movable between a closed or restricted position on a first seat and an open position on a second seat and the movable valve member is biased to the open position by gravety only.

Improved piston cooling can be used to obtain reduced piston temperatures which can provide lower costs through the use of less temperature resistant steel types for the piston, to provide increased margin piston burning, and allow more freedom in the fuel valve atomizer layout, in particular towards the piston.

DK 181438 B1

According to a possible implementation of the first aspect, the at least one cylinder liner is supported by a cylinder frame, the telescopic pipe comprises a static pipe that is physically connected to the cylinder frame and a movable pipe that is 5 physically connected to the crosshead, preferably physically connected to a guide shoe of the crosshead.

According to a possible implementation of the first aspect, the telescopic pipe is configured to expand and contract to follow the movement of the reciprocating crosshead

According to a possible implementation of the first aspect, the valve is arranged upstream, or in the inlet, of the static pipe.

According to a possible implementation of the first aspect, the movable valve member is received in a cavity in a body of the valve, and wherein the shape of the movable valve member in combination with the shape of the cavity provides for damping of the movement of the movable valve member towards the first seat and/or second seat.

According to a possible implementation of the first aspect, the valve is an electronically controlled valve, that opens and closes or restricts in response to a signal from a controller (electronic control unit).

According to a possible implementation of the first aspect, the controller is informed of the position of the movable pipe and configured to time the opening and closing or restricting of the electronically controlled valve as a function of the position of the movable pipe, the controller preferably being configured to close or restrict the electronically controlled valve when telescopic pipe contracts (when the piston moves from BDC to

TDC) and configured to open the electronically controlled valve

DK 181438 B1 6 when the telescopic pipe expands, or the controller is informed of the pressure in the telescopic pipe, and wherein the controller is configured to close or restrict the electronically controlled valve when the pressure is above a threshold and to open the electronically controlled valve when the pressure is below a threshold, or wherein the controller is informed of the pressure in the telescopic pipe and is informed of the pressure supplied by the source and wherein the controller configured to close or restrict the electronically controlled valve when the pressure in the telescopic pipe is equal or higher than the pressure supplied by the source, and wherein the controller is configured to open the electronically controlled valve when the pressure in the telescopic pipe is lower than the pressure supplied by the source. The controller can be informed of the position of the movable pipe directly (e.g. using a position sensor) or by means of knowing the angular position of the crankshaft (e.g. using an angular position sensor on the crankshaft).

According to a possible implementation of the first aspect, the valve is a nonreturn valve.

According to a possible implementation of the first aspect, the inlet port is arranged on a guide shoe of the crosshead, and wherein at least a portion of the conduit extends from the inlet port through the guide shoe, and from the guide shoe to the piston rod, preferably via a crosshead pin.

According to a possible implementation of the first aspect, the movable pipe is at least partially sealingly received in the lumen of the static pipe, or the static pipe is at least partially sealingly received within the lumen of the mobile pipe.

DK 181438 B1 7

According to a possible implementation of the first aspect, the movable pipe is translationally movable relative to the static pipe to follow the reciprocating movement of the crosshead.

According to a possible implementation of the first aspect, the piston 1s cooled by a flow of cooling and lubrication medium supplied to the piston via a telescopic pipe.

According to a possible implementation of the first aspect, the lumen of the telescopic pipe is used to transport the cooling and location medium from a connection point at the cylinder frame or the inlet manifold via the crosshead and a conduit in the piston rod to the piston.

The foregoing and other objects are achieved by aspects of the present disclosure. Further possible implementation forms are apparent from e.g. the description, and the figures.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following detailed portion of the present disclosure, the aspects, embodiments, and implementations will be explained in more detail with reference to the example embodiments shown in the drawings, in which:

Fig. 1 is an elevated front view of a large two-stroke internal combustion engine equipped with a plurality of turbochargers according to an example embodiment,

Fig. 2 is an elevated side view of the large two-stroke internal combustion engine of Fig. 1,

Fig. 3 is a diagrammatic representation of the large two-stroke internal combustion engine according to Fig. 1,

Figs. 4 is a cross-sectional view through the top of the engine frame, the cylinder fame, and the cylinder liner of the engine of Fig. 1, showing a cooling and lubrication medium supply to the crosshead and piston,

DK 181438 B1 8

Fig. 5 is a cross-sectional view of an embodiment of a nonreturn valve in the cooling and lubrication medium supply with the movable valve member in a closed position,

Fig. 6 is a cross-sectional view of the nonreturn valve of Fig. 5 with the movable valve member in an open position,

Fig. 7 is a cross-sectional view of an inner portion of the housing of the nonreturn valve of Fig. 5,

Fig. 8 is a top view of the nonreturn valve of Fig. 5,

Fig. 9 is a cross-sectional view of another embodiment of a nonreturn valve arranged in the cooling and lubrication oil supply with the valve member in a closed position,

Fig. 10, is a cross-sectional view of the nonreturn valve of

Fig. 9 with the movable valve member in a closed position, and

Fig. 11 is a diagrammatic representation of another embodiment in which the nonreturn valve is an electronically controlled one-way valve.

DETAILED DESCRIPTION

Figs. 1, 2, and 3 show a large low-speed turbocharged two-stroke diesel engine 100 with a crankshaft 8 and crossheads 9. Fig. 3 is a diagrammatic representation of the large low-speed turbocharged two-stroke diesel engine with its intake and exhaust systems. In this example embodiment, the engine 100 has six cylinders (each formed by a cylinder liner 1) in line. Large low-speed turbocharged two-stroke diesel engines have typically between four and fourteen cylinders 1 in line, carried by a cylinder frame 29 that is carried by an engine frame 23. The engine 100 may e.g. be used as the main engine in a marine vessel or as a stationary engine for operating a generator in a power station. The total output of the engine 100 may, for example, range from 1,000 to 110,000 kW.

The engine 100 is in this example embodiment a compression- ignited engine 100 of the two-stroke uniflow type with

DK 181438 B1 9 scavenging ports 18 at the lower region of the cylinder liners 1 and a central exhaust valve 4 at the top of each cylinder liner 1. However, it is understood that the engine 100 does not need to be compression ignited (Diesel principle) but can alternatively be a premix engine (Otto principle). Hence, in the present embodiment, the compression pressure of the engine 100 will be sufficiently high for compression ignition, but it is understood that the engine 100 can operate with lower compression pressure and be a premix engine that is ignited by spark or similar means.

Scavenge air is introduced into the cylinders 1 through the intake system. The intake system comprises the scavenge gas receiver 2 connected to the cylinders 1 via the scavenge ports 18.

Fxhaust gas produced in the cylinders is exhausted through the exhaust system, the exhaust system comprising the exhaust gas receiver 3 connected to the cylinders 1 via the exhaust valves 34.

The intake system of the engine 100 comprises a scavenge air receiver 2 (in case exhaust gas recirculation (EGR) is used the scavenge gas receiver will receive a mixture of exhaust gas and scavenge air). The scavenge air is passed from the scavenge air receiver 2 to the scavenge ports 18 of the individual cylinders 1. Apiston 10 that reciprocates in the cylinder liner 1 between the bottom dead center (BDC) and top dead center (TDC) compresses the scavenge air. Fuel is injected through fuel valves 55 that are arranged in the cylinder cover 28 combustion follows, and exhaust gas is generated. Alternatively, the fuel valves 55 are arranged in the cylinder liner and fuel is admitted during the stroke of the piston from BDC to TDC and a mixture of scavenging air and fuel is compressed by the piston 10, and ignition is

DK 181438 B1 10 triggered when the piston 10 is at or near TDC, combustion follows, and exhaust gas is generated.

A central exhaust valve 4 is arranged in a central opening in the cylinder cover 28. A plurality (preferably three or four) of fuel valves 55 is distributed in the cylinder cover 28 around the central opening/exhaust valve 4. The exhaust valve 4 is actuated by an electrohydraulic exhaust valve actuation system (not shown) and controlled by a controller 50 (electronic control unit). The fuel valves 55 are supplied with fuel by a fuel supply system (not shown).

When an exhaust valve 4 is opened, the exhaust gas flows from the central opening in the cylinder covers 28 through an exhaust system that includes an exhaust duct associated with each cylinder 1 into the exhaust gas receiver 3 and onwards through a first exhaust conduit 19 to the turbine 8 of the turbocharger 5 (the engine 100 is provided with a one or more turbochargers 5, from which the exhaust gas flows away through a second exhaust conduit via an economizer 20 to an outlet 21 and into the atmosphere.

Through a shaft in the turbocharger 5, the turbine 8 of the turbocharger 5 drives a compressor 7 supplied with fresh air via an air inlet 12. The compressor 7 delivers pressurized scavenge air to a scavenge air conduit 13 leading to the scavenge air receiver 2. The scavenge air in the scavenge air conduit 13 passes an intercooler 14 and a water mist catcher 63 for cooling the scavenge air and removing water droplets.

The engine is provided with a lubrication system that provides pressurized lubrication medium to various components of the engine. The lubrication medium is also used to cool engine components, including the piston 10. Thus, the lubrication

DK 181438 B1 11 medium is a cooling and lubrication medium and the lubrication system forms a source 40 of pressurized cooling and lubrication medium.

Turning now to Fig. 4, the source 40 is connected via a feed pipe 41 to a stationary pipe 31 of a telescopic pipe 32. The stationary pipe 31 is physically connected to the cylinder frame 29. preferably, the stationary pipe 31 is secured at its upper end to a top plate 28 of the cylinder frame 29 and to a top plate 24 of the engine frame at its lower end. The telescopic pipe 32 comprises a movable pipe 32. In the shown embodiment, the movable pipe 32 is at least partially sealingly received in the lumen of the static pipe 31, but it is understood that the static pipe 31 could just as well be at least partially sealingly received within the lumen of the mobile pipe 32. Thus, the movable pipe 32 is translationally movable relative to the static pipe 31 to follow the reciprocating movement of the crosshead, and the movable pipe 32 moves in unison with the crosshead 9. The movable pipe 32 is in this embodiment secured at its lower end to the guide shoe 27 of the crosshead 9 where it fluidically connects to an inlet port in the crosshead 9. The crankcase frame 23 is provided with vertical guide planes 26 receiving the transverse forces acting on the cross-head 9 and the guide shoe 27 is guided by the vertical guide plates 26. The crosshead 9 further comprises a crosshead pin 16 that connects the guide shoe 27 to a big end that connects to the crankshaft 8.

The telescopic pipe 30 extends from a source of cooling and lubrication medium, that can be formed by a common rail 40 cooling down into the cylinder frame 29 and continues into the crankcase frame 23 to be attached with its lower extremity to the crosshead 9. The telescopic pipe 30 comprises a static tube 31 connected to the common rail 40 and a concentrically arranged

DK 181438 B1 12 movable tube 32 connected to the crosshead 9. The telescopic pipe 30 transports cooling and lubrication medium to a conduit 36 in the crosshead 9 that extends through the piston rod 15 into the piston 10 and back to the piston rod 15 for cooling the piston 10. In this embodiment of the engine 100 each cylinder is provided with one telescopic pipe 30, but it is understood that more than one telescopic pipe 30 can be provided for each cylinder for reasons of redundancy.

In this embodiment, the conduit 36 starts at the inlet port, which is in this embodiment arranged in the upper side of the guide shoe 27, through the guide shoe 27, and through the crosshead pin 16 into the piston rod 15.

A nonreturn valve 33 is fluidically arranged between the telescopic pipe 30 and the source 40. In the present embodiment, the nonreturn valve 33 is arranged at the upper end of the static pipe 31, i.e. at the inlet of the static pipe 31. The nonreturn valve 30 can be supported by the top plate 28 of the cylinder frame 29 or by the intake manifold. The nonreturn valve 30 is configured to allow flow from the source 40 to the telescopic pipe 30 and to prevent flow from the telescopic pipe 30 to the source 40. By preventing return flow, it is ensured that the flow of cooling the lubrication medium to the piston 10 is substantially increased, thereby improving cooling of the piston 10. In particular, the flow of cooling medium to the piston takes place during a much larger portion of a rotation of the crankshaft 8, i.e. in prior art engines, there was no or little flow of cooling medium to the piston 10 during a substantial portion of a rotation of the crankshaft and by preventing return flow, the cooling medium flows to the piston 10 substantially throughout a complete rotation of the crankshaft 8, thereby increasing the average flow rate of cooling medium to the piston 10 and improving cooling of the piston 10.

DK 181438 B1 13

Figs. 5 to 8 are various views of an embodiment of the nonreturn valve 33. Figs. 5 and 6 are cross-sectional views of the embodiment of the nonreturn valve 33 that show the valve member 35 in a closed and open position, respectively. In this embodiment the nonreturn valve 33 comprises a movable valve member 35 in the form of a ball (sphere) that is received in a cavity in the housing of the nonreturn valve 33. The housing of the nonreturn valve 33 is in the present embodiment formed by an outer housing part 39 and an inner housing part 37 that is inserted into the outer housing part 39. As shown, the valve housing is mounted on the top plate 28 of the cylinder frame 23, but it is understood that the nonreturn valve 33 can be secured to the engine 100 in other ways. In this embodiment, the upper end of the stationary pipe 31 is secured to the opposite side of the top plate 28 and the feed pipe 41 connects directly to the nonreturn valve 33, but it is understood that the nonreturn valve 33 can be connected to the source of cooling and lubrication liquid 40 and to the telescopic pipe 30 in other

Ways.

A cavity in the body of the nonreturn valve 33 allows the movable valve member 35 to move between a closed position that is shown in Fig. 5, in which the valve member rests on a first seat, and an open position shown in Fig. 6, in which the valve member rests on a second seat. In this embodiment, the first and second seat are arranged at opposing extremities of the cavity. The first seat is associated with an inlet port of the nonreturn valve and the second seat is associated with an outlet port of the nonreturn valve. The cavity also comprises one or more side passages 36 that establish a fluidic connection around the movable valve member 35 for allowing the cooling and lubrication liquid to pass around the movable valve member 35 for flowing from the inlet port towards the outlet port. The first seat is

DK 181438 B1 14 shaped to form a hermetic seal with the movable valve member 35 when the movable valve member rests on the first seat to prevent flow of cooling and lubrication medium in the direction from the outlet to the inlet. The second seat is shaped to establish one or more openings between the second seat and the movable valve member 35 to enable passage of the cooling and lubrication medium between the movable valve member 35 and the second seat when the movable valve member 35 rests on the second seat, as shown in

Fig. 6. These openings are this embodiment established by a plurality axially directed and circumferentially distributed bores in the inner housing part 37 that meet with the as such substantially conically shaped second seat, also formed by the inner housing part.

In the present embodiment, there are no biasing means that urge the movable valve member towards either the open or closed position, except for the earth/s gravity field urging the movable valve member 35 towards the open seat/position. During operation of the engine 100, the position of the movable valve member 35 is determined by the pressure differential over the nonreturn valve 33, which results in forces on the movable valve member 35 that are many times larger than the force caused by the effect of gravity on the movable valve member 35, which will have only a marginal influence on the movement of the movable valve member during engine operation. When the pressure at the inlet of the nonreturn valve 33 i.e. the pressure in the feed conduit 41, is higher than the pressure at the outlet of the nonreturn valve 33 (i.e. the pressure in the stationary pipe 31) the movable valve member 35 is urged by the pressure differential acting on the movable valve member 35 towards the open seat as shown in Fig. 6, and flow of cooling the lubrication medium from the inlet of the nonreturn valve 33 to the outlet of the nonreturn valve 33 is enabled. When the pressure at the inlet of the nonreturn valve 33 is lower than the pressure at the

DK 181438 B1 15 outlet of the nonreturn valve, the movable valve member 35 is urged by the pressure differential acting on the movable valve member 35 towards the closed seat, and flow of cooling and lubrication medium from the outlet of the nonreturn vale 33 towards the inlet of the nonreturn valve 33 is prevented.

Figs. 10 and 11 illustrate another embodiment of the nonreturn valve 33. In this embodiment, structures and features that are the same or similar to corresponding structures and features previously described or shown herein are denoted by the same reference numeral as previously used for simplicity. In this embodiment, the movable valve member 35 is a cylindrical body with stepwise varying diameter and the cavity is shaped accordingly. The nonreturn valve 33 is shown with the movable valve member 35 in the open position in Fig. 9 and with the movable map member 35 in the closed position in Fig. 10. The stepwise changes in the diameter cause the interaction between the movable valve member 35 and the cavity to form a damper for the movement of the movable valve member 35 towards the first seat and towards the second seat to ensure a soft landing of the movable valve member 35 on the respective seat. A first damping chamber 38 traps cooling and lubrication medium when the movable valve member 35 moves towards the first seat and requires the trapped cooling and lubrication medium to be squeezed out of the first damping chamber 38 through a clearance between the movable valve in the 35 and the surface of the valve housing that forms the cavity. A second damping chamber 39 traps the cooling and lubrication medium when the movable valve member 35 moves towards the second seat and requires the trapped cooling and lubrication medium to be squeezed out of the second damping chamber 39 through a clearance between the movable valve member and the surface of the valve housing that forms the cavity.

In this embodiment, the extremity of the side passage 36 forms the outlet port of the nonreturn valve 33. Other than the damping

DK 181438 B1 16 function, the operation of the nonreturn valve 33 according to this embodiment is the same as that for the embodiment of Figs. to 8. 5 In a variation of the embodiments above and below, the closed position is not completely closed but almost completely closed, thereby posing a restriction to flow of cooling and lubricating medium.

Fig. 11 illustrates another embodiment of the nonreturn valve 33. In this embodiment, structures and features that are the same or similar to corresponding structures and features previously described or shown herein are denoted by the same reference numeral as previously used for simplicity. In this embodiment, the nonreturn valve 33 is an electronically controlled 2/2 valve. In this embodiment, the electronically controlled 2/2 is mechanically biased to the open position and movable to the closed or restricted position by an electric actuator, but it is understood that other types of electronically controlled 2/2 valves are equally suitable as nonreturn valve 33. The electronically controlled nonreturn valve 33 is controlled by a signal from a controller 50 (electronic control unit). In an embodiment, the controller 50 is informed of the position of the movable pipe 32 and configured to time the opening and closing/restricting the electronically controlled valve 33 as a function of the position of the movable pipe 32, i.e. the controller 50 is configured to close or restrict the electronically controlled nonreturn valve 33 when the telescopic pipe 30 contracts and configured to open the electronically controlled nonreturn valve 33 when the telescopic pipe 30 expands. The position of the movable pipe 32 is in an embodiment determined by a position sensor (not shown) associated with the movable pipe 32, and transmitted to the controller 50. Alternatively, the position of the movable pipe

DK 181438 B1 17 is indirectly determined from the rotational position of the crankshaft 8 through a position sensor 77 and the controller 50 is informed of the signal from the position sensor 77. In another embodiment, the controller 50 is informed of the pressure in the telescopic pipe 30, e.g. from a pressure sensor, and the controller 50 is configured to close or restrict the electronically controlled valve 33 when the pressure is above a threshold, and to open the electronically controlled nonreturn valve 33 when the pressure is below the threshold. In another embodiment, the controller 50 is informed of the pressure in the telescopic pipe 30, e.g. from a pressure sensor, and is informed of the pressure supplied by the source 40, e.g. from another pressure sensor measuring the pressure in the feed conduit 41, and the controller 50 is configured to close or restrict the electronically controlled nonreturn valve 33 when the pressure in the telescopic pipe 1s equal or higher than the pressure supplied by the source, and wherein the controller 50 is configured to open electronically controlled nonreturn valve 33 when the pressure in the telescopic pipe is lower than the pressure in the feed conduit 41. Thus, in operation, return flow through of the cooling the lubrication liquid from the telescopic pipe 30 towards the source 40 is prevented or reduced.

For all of the embodiments, the telescopic pipe 30 acts as a positive displacement pump when it contracts and simultaneously return flow from the telescopic pipe 30 towards the source is prevented or restricted. Thus, a more constant flow of cooling the lubrication medium to the piston 10, and hence improved cooling of the piston 10 is ensured.

The engine has been described in conjunction with various embodiments herein. However, other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed subject matter, from a study

DK 181438 B1 18 of the drawings, the disclosure, and the appended claims. In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. A single controller or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage.

The reference signs used in the claims shall not be construed as limiting the scope. Unless otherwise indicated, the drawings are intended to be read (e.g., cross-hatching, arrangement of parts, proportion, degree, etc.) together with the specification, and are to be considered a portion of the entire written description of this disclosure. As used in the description, the terms “horizontal”, “vertical”, “left”, “right”, “up” and “down”, simply refer to the orientation of the illustrated structure as the particular drawing figure faces the reader.

Claims

DK 181438 B1 19 PATENTKRAVDK 181438 B1 19 PATENT CLAIM

1. Stor, turboladet, totaktsforbrændingsmotor (100) med længdeskylning af typen med krydshoved, hvilken motor (100) omfatter: mindst én cylinderforing (1) med skylleporte (18) ved dens nedre ende og en udstødningsventil (4) ved dens øvre ende, et frem- og tilbagegående stempel (10) i den mindst ene cylinderforing (1), hvilket frem- og tilbagegående stempel (10) er forbundet med et frem- og tilbagegående krydshoved (9) via en stempelstang (15), en kilde (40) af tryksat og afkølende smøremiddel, et teleskopisk rør (30), der fluidmæssigt forbinder kilden med en indløbsport på krydshovedet (9), en ledning (36), der strækker sig fra indløbsporten til stemplet (10), hvilken ledning (36) fortrinsvis strækker sig gennem krydshovedet (9) og gennem stempelstangen (15), og en ventil (33), der er konfigureret til at muliggøre strømning af køle- og smøremiddel fra kilden (40) til det teleskopiske rør (30) og forhindre eller mindst begrænse strømning af køle- og smøremidlet fra det teleskopiske rør (30) til kilden (40), hvori ventilen (33) omfatter et bevægeligt ventilelement (35), der er indrettet til at kunne bevæge sig mellem en lukket eller begrænset position på et første sæde og en åben position på et andet sæde, kendetgnet ved at det bevægelige ventilelement (35) alene påvirkes til den åbne position ved tyngdekraft.1. A large, turbocharged, cross-head type longitudinally scavenged two-stroke internal combustion engine (100), said engine (100) comprising: at least one cylinder liner (1) having scavenging ports (18) at its lower end and an exhaust valve (4) at its upper end, a reciprocating piston (10) in the at least one cylinder liner (1), which reciprocating piston (10) is connected to a reciprocating cross head (9) via a piston rod (15), a spring (40 ) of pressurized and cooling lubricant, a telescopic tube (30) fluidly connecting the source to an inlet port on the crosshead (9), a line (36) extending from the inlet port to the piston (10), which line (36) preferably extending through the crosshead (9) and through the piston rod (15), and a valve (33) configured to allow flow of coolant and lubricant from the source (40) to the telescopic tube (30) and prevent or at least limit flow of the coolant and lubricant from the telescopic pipe (30) to the source (40), wherein the valve (33) comprises a movable valve member (35) adapted to be able to move between a closed or restricted position on a first seat and an open position on a second seat, characterized in that the movable valve element (35) is only influenced to the open position by gravity.

2. Motor (100) ifølge krav 1, hvor den mindst ene cylinderforing (1) understøttes af en cylinderramme (29), det teleskopiske rør (30) omfatter et statisk rør (31), der er fysisk forbundet med cylinderrammen (29), og et bevægeligt rør (32), der er fysisk forbundet med krydshovedet (9), fortrinsvis fysisk forbundet med en føringssko (29) til krydshovedet (9).2. Engine (100) according to claim 1, wherein the at least one cylinder liner (1) is supported by a cylinder frame (29), the telescopic tube (30) comprises a static tube (31) that is physically connected to the cylinder frame (29), and a movable tube (32) physically connected to the crosshead (9), preferably physically connected to a guide shoe (29) to the crosshead (9).

3. Motor (100) ifølge krav 2 hvor ventilen (33) er anbragt opstrøms for eller i indløbet til det statiske rør (31).3. Motor (100) according to claim 2, where the valve (33) is arranged upstream of or in the inlet to the static pipe (31).

DK 181438 B1 20DK 181438 B1 20

4. Motor (100) ifelge et hvilket som helst af kravene 1 til 3, hvor det bevægelige ventilelement (35) modtages i et hulrum i et legeme (37, 39) af ventilen (33), og hvor det bevægelige ventilelements (35) form kombineret med hulrummets form tilvejebringer dæmpning af det bevægelige ventilelements (35) bevægelse mod det første sæde og/eller andet sæde.4. Engine (100) according to any one of claims 1 to 3, wherein the movable valve element (35) is received in a cavity in a body (37, 39) of the valve (33), and wherein the movable valve element (35) shape combined with the shape of the cavity provides damping of the movement of the movable valve element (35) towards the first seat and/or second seat.

5. Motor (100) ifølge et hvilket som helst af kravene 1 til 4, hvor ventilen (33) er en kontraventil.Engine (100) according to any one of claims 1 to 4, wherein the valve (33) is a non-return valve.

6. Motor (100) ifølge et hvilket som helst af kravene 1 til 5, hvor ventilen (33) er en elektronisk styret ventil, der åbnes og lukkes eller begrænses som reaktion på et signal fra en styreenhed (530).An engine (100) according to any one of claims 1 to 5, wherein the valve (33) is an electronically controlled valve that is opened and closed or restricted in response to a signal from a control unit (530).

7. Motor (100) ifølge krav 6, hvor styreenheden (50) informeres om det bevægelige rørs (32) position og er konfigureret til at time åbningen og lukningen eller begrænsningen af den elektronisk styrede ventil som en funktion af det bevægelige rørs (32) position, hvor styreenheden (50) fortrinsvis er konfigureret til at lukke eller begrænse den elektronisk styrede ventil, når det teleskopiske rør (30) sammentrækkes, og konfigureret til at åbne den elektronisk styrede ventil, når det teleskopiske rør udvides.The motor (100) of claim 6, wherein the control unit (50) is informed of the position of the movable pipe (32) and is configured to time the opening and closing or restriction of the electronically controlled valve as a function of the movable pipe (32). position, wherein the control unit (50) is preferably configured to close or restrict the electronically controlled valve when the telescopic tube (30) is contracted, and configured to open the electronically controlled valve when the telescopic tube is expanded.

8. Motor (100) ifølge krav 7, hvor styreenheden (50) informeres om trykket i det teleskopiske rør (30), og hvor styreenheden (530) er konfigureret til at lukke eller begrænse den elektronisk styrede ventil, når trykket er over en tærskel, eller hvor styreenheden (50) informeres om trykket i det teleskopiske rør (30) og informeres om trykket tilført af kilden (40), og hvor styreenheden (50) er konfigureret til at lukke eller begrænse den elektronisk styrede ventil, når trykket i det teleskopiske rør (30) er på eller større end trykket tilført af kilden (40) eller et måltryk, og hvor styreenheden er konfigureret til at åbne den elektronisk styrede ventil, når trykket i det teleskopiske rør (30) er lavere end trykket tilført af kilden (40) eller måltrykket.8. Engine (100) according to claim 7, wherein the control unit (50) is informed of the pressure in the telescopic tube (30) and wherein the control unit (530) is configured to close or restrict the electronically controlled valve when the pressure is above a threshold , or wherein the control unit (50) is informed of the pressure in the telescopic tube (30) and is informed of the pressure supplied by the source (40), and wherein the control unit (50) is configured to close or limit the electronically controlled valve when the pressure in the telescoping tube (30) is at or greater than the pressure supplied by the source (40) or a target pressure, and wherein the control unit is configured to open the electronically controlled valve when the pressure in the telescoping tube (30) is lower than the pressure supplied by the source (40) or the target pressure.