DK173620B1

DK173620B1 - Process for cleaning a hydraulic system by a cylinder in a multi-cylinder internal combustion engine, as well as a hydraulic system by such a cylinder

Info

Publication number: DK173620B1
Application number: DK63497A
Authority: DK
Inventors: Henning Lindquist; Poul Cenker
Original assignee: Man B & W Diesel As
Priority date: 1997-05-30
Filing date: 1997-05-30
Publication date: 2001-05-07
Also published as: DK63497A; JP3831521B2; JPH10339120A

Description

i DK 173620 B1in DK 173620 B1

Opfindelsen angår en fremgangsmåde til rensning af et hydrauliksystem ved en cylinder i en flercylindret forbrændingsmotor, der i hver cylinder har en udstødsventil med en hydraulisk aktuator med et trykkam-5 mer, der periodevis for aktivering af udstødsventilen tilføres højtryks hydraulikvæske fra en tilgangskanal.The invention relates to a method for cleaning a hydraulic system by a cylinder of a multi-cylinder internal combustion engine, which in each cylinder has an exhaust valve with a hydraulic actuator with a pressure chamber, which is periodically supplied to activate the exhaust valve with a high pressure hydraulic fluid from an inlet duct.

Fra GB 2 302 041 A beskriver et filter i et hydraulisk system, hvor filteret renses hydraulisk ved tvangsmæssigt at gennemføre en periode med tilbage-10 skylning af hydraulikmiddel, hver gang det hydrauliske system startes ved tryksætning af fødeledningen.From GB 2 302 041 A describes a filter in a hydraulic system where the filter is hydraulically cleaned by forcibly performing a period of back flushing of hydraulic fluid each time the hydraulic system is started by pressurizing the feed line.

Rensning ved hydraulisk tilbageskylning af et filter er således kendt.Thus, cleaning by hydraulic backwashing of a filter is known.

Det er velkendt, at udstødsventilerne i en totakts 15 forbrændingsmotor kan åbnes ved hjælp af en hydraulisk aktuator med et trykkammer, der for åbning af ventilen aktiveres ved tilførsel af højtryks hydraulikvæske fra en tilgangskanal, der er forbundet med en trykledning.It is well known that the exhaust valves of a two-stroke internal combustion engine can be opened by means of a hydraulic actuator with a pressure chamber which, for opening the valve, is actuated by supplying high pressure hydraulic fluid from an inlet channel connected to a pressure line.

En sådan ventilaktivering er eksempelvis beskrevet i 20 ansøgerens DK-B 154155, hvor aktuatorens stempel er todelt og passerer med snæver pasning forbi afskæringskanter i den tilhørende aktuatorcylinder. Et andet eksempel kendes fra US-A 3 209 737, hvor den hydraulisk aktiverede udstødsventil kan åbnes ved hjælp af et 25 aktuatorstempel, der er bevægeligt i en aktuatorcylinder, når trykkammeret tilføres højtryks hydraulikvæske.Such a valve actuation is described, for example, in applicant's DK-B 154155, where the actuator piston is bipartite and passes with a narrow fit past the cut-off edges of the associated actuator cylinder. Another example is known from US-A-3 209 737, wherein the hydraulically actuated exhaust valve can be opened by means of an actuator piston which is movable in an actuator cylinder when the pressure chamber is supplied with high pressure hydraulic fluid.

Det er ligeledes velkendt, at de hydrauliske elementer er meget følsomme over for snavs og andre urenheder i det hydrauliske system, og at det kan være 30 nødvendigt at standse motoren for at reparere eller rense det hydrauliske system på en eller flere cylindre. Sådanne driftsstop er særdeles uønskede, fordi de giver motoren mindre pålidelighed. Navnlig på skibs-motorer er fuldkommen eller den størst mulige drifts-35 sikkerhed af stor betydning, fordi det af hensyn til DK 173620 B1 2 skibets sikkerhed kan være påkrævet at fortsætte motordriften, selv om der skulle være driftsproblemer.It is also well known that the hydraulic elements are very sensitive to dirt and other impurities in the hydraulic system and that it may be necessary to stop the engine to repair or clean the hydraulic system on one or more cylinders. Such shutdowns are highly undesirable because they give the engine less reliability. In particular, ship engines are perfect or the greatest possible operational safety is of great importance because, for reasons of DK 173620 B1 2, ship safety may be required to continue engine operation, even if there are operational problems.

Det er et særligt problem, at enhver adskillelse af det hydrauliske system i sig selv er en kilde til 5 introduktion af nye urenheder i systemet, og der kan derfor ved de sædvanlige rensninger med adskilt system ikke opnås tilfredsstillende sikkerhed mod nye driftsproblemer. Det er også en ulempe ved hydrauliske systemer på motorer, at eventuelle urenheder ofte først 10 giver sig til kende som driftsproblemer for motoren efter længere tids drift efter samlingen af systemet.It is a particular problem that any separation of the hydraulic system is in itself a source of introduction of new impurities into the system, and therefore, with the usual purifications with separate system, satisfactory safety against new operating problems cannot be obtained. It is also a disadvantage of hydraulic systems on engines that any impurities often first become known as operating problems for the engine after prolonged operation after assembly of the system.

Opfindelsen har til formål at give motoren stor sikkerhed mod utilsigtet standsning som følge af svigt i det hydrauliske system samt at forenkle montering og 15 vedligehold af det hydrauliske system.The invention aims to provide the engine with great safety against unintentional shutdown due to failure of the hydraulic system as well as to simplify installation and maintenance of the hydraulic system.

Med henblik herpå er fremgangsmåden ifølge opfindelsen ejendommelig ved, at en periode med hydraulisk rensning gennemføres, mens hydrauliksystemet er samlet, ved at tilgangskanalen forbindes med et tilba-20 geløb og tryksat hydraulikvæske tilføres aktuatorens trykkammer fra en sekundær ledning.To this end, the method according to the invention is characterized in that a period of hydraulic cleaning is carried out while the hydraulic system is assembled, by connecting the inlet duct with a reflux and pressurized hydraulic fluid to the pressure chamber of the actuator from a secondary conduit.

Ved at forbinde aktuatorens tilgangskanal med tilbageløbet og at gennemskylle det hydrauliske system ved tilførsel af hydraulikvæske fra den sekundære 25 ledning til trykkammeret, foretages gennemskylningen fra toppen af systemet, hvilket fremmer fjernelsen af urenheder, der skylles med væsken nedad gennem systemet og eksempelvis ud gennem et dræn. Endvidere tilføres den rene hydraulikvæske på et skidtfølsomt sted, nemlig 30 i aktuatoren, hvor der i drift hersker store kræfter og er indbyrdes bevægelige dele, som er sammenpasset med snævre tolerancer. Det er endvidere en betydelig fordel, at rensningen foregår, mens systemet er samlet og ved hjælp af systemet egne komponenter, så der ikke 35 kan introduceres nye urenheder i forbindelse med rens- DK 173620 B1 3 ningens afslutning, hvor de tidligere kendte systemer som nævnt skal gensamles til den oprindelige driftskonfiguration. Rensningen på denne måde giver motoren væsentlig større driftssikkerhed. Det er endvidere 5 betydeligt lettere at udføre rensningen, fordi den foregår med lukket system, der selv sørger for tilførsel og bortledning af den rensende hydraulikvæske.By connecting the actuator inlet channel to the reflux and flushing the hydraulic system by supplying hydraulic fluid from the secondary conduit to the pressure chamber, the flushing is performed from the top of the system, which promotes the removal of impurities flushed with the liquid downward through the system and e.g. drain. Furthermore, the clean hydraulic fluid is supplied in a dirt-sensitive location, namely 30 in the actuator, where large forces are in operation and there are mutually moving parts which are matched with narrow tolerances. Furthermore, it is a significant advantage that the cleaning takes place while the system is assembled and using the system's own components, so that no new impurities can be introduced in connection with the end of the cleaning, where the previously known systems mentioned must be reassembled to the original operating configuration. The cleaning in this way gives the engine significantly greater reliability. Furthermore, it is considerably easier to perform the cleaning because it is carried out with a closed system, which itself provides for the supply and discharge of the cleaning hydraulic fluid.

Det er muligt at gennemføre perioden med hydraulisk rensning på én af motorens cylindre, mens motoren 10 er i drift på de øvrige cylindre. Hvis der konstateres driftsproblemer i det hydrauliske system på en cylinder, opnås dermed den fordel, at motoren ikke skal standses, men kun køre med lidt nedsat belastning, mens cylinderen med driftsproblemer tages ud af drift og 15 renses. Da der ikke skal foretages adskillelse af det hydrauliske system for at gennemføre rensningen, er der ingen forøget risiko for brand eller andre skader som følge af udtrængning af driftsvarm hydraulikvæske, der ville kunne ramme driftsvarme motordele.It is possible to carry out the period of hydraulic cleaning on one of the cylinders of the engine, while the motor 10 is in operation on the other cylinders. Thus, if operating problems are found in the hydraulic system of a cylinder, the advantage is obtained that the engine should not be stopped, but only run with a little reduced load, while the cylinder with operating problems is taken out of operation and cleaned. Since the hydraulic system does not need to be separated to perform the cleaning, there is no increased risk of fire or other damage due to the extraction of operating hot hydraulic fluid that could affect operating engine parts.

20 Perioden med hydraulisk rensning kan hensigts mæssigt gennemføres, efter at hydrauliksystemet hørende til cylinderen har været i det mindste delvis adskilt og samlet igen. Derved mindskes eller fjernes risikoen for driftsproblemer forårsaget af afskillelsen af en 25 eller flere dele i det hydrauliske system hørende til cylinderen. Denne fremgangsmåde kan også udnyttes til at foretage hurtigere montering af delene i det hydrauliske system end det tidligere har været muligt, fordi eventuelle urenheder problemløst kan bortskylles efter 30 tilendebragt samling af systemet, og inden dette igen sættes i sædvanlig drift.The period of hydraulic cleaning can conveniently be carried out after the hydraulic system of the cylinder has been at least partially separated and reassembled. This reduces or eliminates the risk of operating problems caused by the separation of 25 or more parts of the hydraulic system of the cylinder. This method can also be utilized to make faster mounting of the parts of the hydraulic system than previously possible, because any impurities can be cleansed without problems after 30 complete assembly of the system and before being put back into normal operation.

Det er muligt at udforme cylinderens hydrauliksystem på sådan måde, at den periodevise tilførsel af højtryks hydraulikvæske styres ved hjælp af en ved 35 aktuatoren beliggende styreventil, der ved normal drift DK 173620 B1 4 skiftevis tilslutter aktuatorkammeret til en højtryksledning og til den sekundære ledning, der ved den normale drift er tilsluttet et tilbageløb, og at den sekundære ledning i perioden med hydraulisk rensning 5 forbindes med en kilde for tryksat hydraulikvæske ved hjælp af mindst en omstillingsventil. Placeringen af styreventilen oppe ved aktuatoren giver den fordel, at højtryksledningen med vedvarende højt hydrauliktryk ved normal drift er ført helt op til umiddelbart i nærheden 10 af aktuatoren gennem en afgrening fra hovedhøjtryksledningen, som fra en pumpestation forsyner alle motorens cylindre med hydraulikvæske ved højtryk, så der hverken er nogen risiko for luftindtrængninger i systemet, eller fremkommer generende tryksvingninger i strømning-15 banen mellem styreventilen og aktuatoren, hvilke tryksvingninger i visse tilfælde kan forekomme ved ventilaktiveringen, når styreventilen ligger i større afstand, eksempelvis fra 0,5 til 2 meter eller mere fra aktuatoren, og væsken i den forholdsvis lange strøm-20 ningsbane komprimeres og trykaflastes.It is possible to design the hydraulic system of the cylinder in such a way that the periodic supply of high pressure hydraulic fluid is controlled by means of a control valve located at the actuator, which in normal operation connects the actuator chamber alternately to a high pressure line and to the secondary line which in the normal operation, a reflux is connected and the secondary line during the period of hydraulic cleaning 5 is connected to a source of pressurized hydraulic fluid by means of at least one switching valve. The positioning of the control valve up at the actuator gives the advantage that the high-pressure line with sustained high hydraulic pressure in normal operation is fed right up to the immediate vicinity of the actuator through a branch from the main high-pressure line, which supplies a high pressure hydraulic fluid from all pump cylinders from a pump station. there is no risk of air intrusions into the system, nor are there any disturbing pressure fluctuations in the flow path between the control valve and the actuator, which pressure fluctuations can sometimes occur during valve actuation when the control valve is at a greater distance, for example from 0.5 to 2 meters, or more from the actuator and the liquid in the relatively long flow path is compressed and relieved by pressure.

Fremføringen af højtrykket op til aktuatoren gennem afgreningen og bortledningen af den i aktuatoren forbrugte væske gennem den sekundære ledning giver også sikkerhed for, at aktuatoren gennemstrømmes af store 25 mængder hydraulikvæske, hvilket giver en effektiv fjernelse af den varme, der udvikles i aktuatoren ved afbremsning af udstødsventilens bevægelser nær dennes yderstillinger ved hjælp af en eller flere aktuator-stempeldele i aktuatorcylinderen.The transmission of the high pressure up to the actuator through the branching and discharge of the liquid consumed in the actuator through the secondary conduit also ensures that the actuator is flowed through large quantities of hydraulic fluid, which provides an effective removal of the heat generated in the actuator by braking the the movements of the exhaust valve near its outer positions by means of one or more actuator piston parts in the actuator cylinder.

30 Ved at tilslutte aktuatoren til den sekundære ledning, når højtrykket skal afbrydes for fremkaldelse af lukning af udstødsventilen opnås, at den i aktuatoren forbrugte hydraulikvæske returneres til et tilbageløb gennem den eksisterende sekundære ledning.30 By connecting the actuator to the secondary conduit, when the high pressure is to be disconnected to cause the closing of the exhaust valve, the hydraulic fluid consumed in the actuator is returned to a reflux through the existing secondary conduit.

3 5 Denne ledning kan også anvendes som dræn fra aktua- DK 173620 B1 5 torens hus, og der kan i så fald med fordel være en ud til den sekundære ledning åbnende kontraventil ved drænafløbet fra huset for at hindre trykpulsationen fra styreventilens bortledning af højtrykket i aktuatoren 5 i at slå ind gennem drænafløbet. Når der skal gennemføres en periode med hydraulisk rensning, forbindes afgreningen fra hovedhøjtryksledningen til et tilbageløb, så trykkammeret i aktuatoren er drænet for hydraulikvæske, og derefter aktiveres omstillings-10 ventilen til at forbinde den sekundære ledning med kilden for tryksat hydraulikvæske, der eksempelvis kan levere hydraulikvæske ved et tryk beliggende i intervallet fra 2 til 25 bar til aktuatoren.This conduit can also be used as a drain from the actuator housing and in that case there may advantageously be a check valve opening to the secondary conduit at the drain outlet from the housing to prevent the pressure pulsation from the control valve's discharge of the high pressure in the actuator. the actuator 5 in turning through the drain. When a period of hydraulic cleaning is to be carried out, the branch from the main high-pressure line is connected to a reflux so that the pressure chamber in the actuator is drained for hydraulic fluid, and then the switching valve is activated to connect the secondary line with the source of pressurized hydraulic fluid which can, for example, deliver hydraulic fluid at a pressure in the range from 2 to 25 bar to the actuator.

Når hydraulikvæsken strømmer baglæns ind i gennem 15 aktuatoren, sker der kraftig omhvirvling af væske i trykkammeret, og den tilledte væske styrter ned gennem afgreningen og ud gennem tilbageløbet, der kan være forbundet til et dræn ved atmosfæretryk. De kraftige væskebevægelser i aktuatoren og i strømningsbanen ned 20 til drænet, giver en meget effektiv rensning af cylinderens hydrauliksystem. Når rensningen er tilendebragt, aktiveres omstillingsventilen til sin normale stilling, og afgreningen tilsluttes højtryksledningen, hvorefter cylinderen kan sættes i drift. Ved de første aktiverin-25 ger af aktuatoren river højtryksvæsken, hvis tryk eksempelvis kan være beliggende i intervallet fra 125 til 325 bar, al luften med ud af aktuatorkammeret, når styreventilen forbinder trykkammeret med den sekundære ledning.As the hydraulic fluid flows backwards into the actuator, vigorous fluid flow occurs in the pressure chamber and the entrained fluid crashes down through the branch and out through the backflow, which may be connected to a drain at atmospheric pressure. The strong fluid movements in the actuator and in the flow path down to the drain provide a very efficient cleaning of the hydraulic system of the cylinder. When the cleaning is completed, the switch valve is activated to its normal position and the branch is connected to the high pressure line, after which the cylinder can be put into operation. At the first actuations of the actuator, the high-pressure liquid, whose pressure can, for example, be in the range of 125 to 325 bar, tears all the air out of the actuator chamber as the control valve connects the pressure chamber with the secondary conduit.

30 Det er alternativt muligt at udforme cylinderens hydrauliksystem på sådan måde, at den periodevise tilførsel af højtryks hydraulikvæske styres ved hjælp af en styreventil, der er beliggende i afstand fra aktuatoren, fortrinsvis på en fordelerblok placeret i lavere 35 niveau end aktuatoren, at ved normal drift tilføres DK 173620 B1 6 højtryksvæsken fra styreventilen til aktuatorens tilgangskanal gennem en primær trykledning, og at ved gennemførelsen af perioden med rensning forbindes den primære trykledning til et tilbageløb og forbindes den 5 sekundære ledning med en kilde for tryksat hydraulikvæske ved hjælp af mindst en omstillingsventil. Dette giver den fordel, at styreventilerne kan placeres i nærheden af hinanden i en højde, der giver nem adgang til inspektion. Hvad angår energiforbruget til drift af 10 udstødsventilen kan anvendelsen af den primære trykledning til at føre højtrykket fra styreventilen op til aktuatoren være fordelagtig, blandt andet fordi der, mens udstødsventilen står lukket, er god tid til at bortlede hydraulikvæske ved lavt tryk fra trykkammeret 15 for borttransportering af den i aktuatoren udviklede varme. Når rensningen ønskes foretaget, forbindes den primære trykledning til et tilbageløb, der kan være tilsluttet et dræn eller en returledning med passende lavt tryk, og omstillingsventilen forbinder den sekun-20 dære ledning til trykkilden, hvorefter rensningen foregår som beskrevet ovenfor.Alternatively, it is possible to design the hydraulic system of the cylinder such that the periodic supply of high pressure hydraulic fluid is controlled by a control valve located at a distance from the actuator, preferably at a distributor block located at a lower level than the actuator, that at normal In operation, the high pressure fluid is supplied from the control valve to the actuator's supply channel through a primary pressure line, and when the cleaning period is completed, the primary pressure line is connected to a reflux and the 5 secondary line is connected to a source of pressurized hydraulic fluid by means of at least one switching valve. . This gives the advantage that the control valves can be placed close to each other at a height that allows easy access for inspection. Regarding the energy consumption for operating the exhaust valve, the use of the primary pressure line to carry the high pressure from the control valve up to the actuator may be advantageous, inter alia because while the exhaust valve is closed, there is good time to drain hydraulic fluid at low pressure from the pressure chamber 15 for conveying away the heat developed in the actuator. When purification is desired, the primary pressure line is connected to a reflux which may be connected to a drain or return line of appropriate low pressure, and the switch valve connects the secondary line to the pressure source, after which the cleaning is performed as described above.

De to nævnte varianter af fremgangsmåden kan begge med fordel anvendes således, at tilgangskanalen i aktuatoren automatisk forbindes til tilbageløbet, hvis 25 højtrykket i en tilgangsport på styreventilen bliver mindre end en forudbestemt værdi, og dette kan fortrinsvis ske ved hjælp af en trykstyret ventil, der ved normal drift holdes i inaktiv stilling ved hjælp af nævnte højtryk. Sikkerheden mod indtrængning af uren-30 heder i cylindrenes hydrauliksystemer bliver særdeles stor med denne fjernelse af hydraulikvæskens tryk fra aktuatoren, når højtrykket fjernes fra styreventilen.The two variants of the method can both advantageously be used such that the inlet channel of the actuator is automatically connected to the reflux if the high pressure in an inlet port of the control valve becomes less than a predetermined value, and this can preferably be done by means of a pressure controlled valve which in normal operation, hold in idle position by means of said high pressure. The safety of impurities entering the hydraulic systems of the cylinders becomes extremely high with this removal of the hydraulic fluid pressure from the actuator when the high pressure is removed from the control valve.

Den automatiske bortledning af trykket med eventuel tilknyttet tømning af aktuatoren for væske, hvis 35 tilbageløbet er forbundet til et dræn i stedet for til DK 173620 B1 7 en returledning, er eksempelvis virksom, når motoren standses, eller hvis højtrykket på en enkelt cylinder afbrydes for eftersyn eller adskillelse af dele i hydrauliksystemet. Da virkningen er automatisk, er der 5 stor sikkerhed mod betjeningsfejl, idet maskinpersona-let ikke kan glemme at tømme aktuatoren og heller ikke kan foretage fejlbetjeninger. Dette gør hydrauliksystemet særdeles betjeningsvenligt og fejlsikkert.The automatic discharge of the pressure with any associated discharge of the fluid actuator, if the reflux is connected to a drain instead of a return line, is, for example, effective when the engine is stopped or if the high pressure on a single cylinder is switched off. overhaul or separation of parts in the hydraulic system. Since the effect is automatic, there is great security against operating errors, since the machine personnel cannot forget to empty the actuator and can not make errors. This makes the hydraulic system extremely user-friendly and safe.

Den automatiske virkemåde kan hensigtsmæssigt 10 tilvejebringes derved, at den trykstyrede ventil vedvarende belastes af en kraft i retning af sin aktive stilling, hvori den forbinder den primære trykledning med tilbageløbet. Hvis den trykstyrede ventil ikke påvirkes af andre indstillingskræfter, vil den af 15 kraften føres til den aktive stilling, i hvilken aktua-torkammeret ikke kan tilføres urenheder, og cylinderens hydrauliksystem står klar til udførelse af en strømningsrensning med hydraulikvæske.Conveniently, the automatic mode of operation may be provided in that the pressure-controlled valve is continuously loaded by a force in the direction of its active position, in which it connects the primary pressure line to the reflux. If the pressure-controlled valve is not affected by other adjusting forces, it will be guided by the force to the active position in which the actuator chamber cannot be supplied with impurities and the hydraulic system of the cylinder is ready to perform a flow cleaning with hydraulic fluid.

Motoren kan med fordel være udformet således, at 2 0 også brændselsleveringen til cylindrene foretages ved_ hjælp af hydrauliktryk, idet dette allerede står til rådighed ved cylindrene af hensyn til aktiveringen af udstødsventilerne. Det foretrækkes derfor, at en tilgangskanal til et hydraulisk drev for en brændselspumpe 25 hørende til samme cylinder som udstødsventilen forbindes med tilbageløbet ved hjælp af den trykstyrede ventil, når denne bevæges til sin aktive stilling.The engine may advantageously be designed such that fuel delivery to the cylinders is also effected by hydraulic pressure, as this is already available at the cylinders for the purpose of activating the exhaust valves. It is therefore preferred that an inlet channel for a hydraulic drive for a fuel pump 25 of the same cylinder as the exhaust valve is connected to the reflux by means of the pressure controlled valve as it is moved to its active position.

Dette giver en samtidig afspærring af højtrykket til forbrugsstederne på cylinderen, så at cylinderens 30 hydrauliksystem enten er fuldt aktivt eller fuldt udkoblet. Det er endvidere muligt, at den trykstyrede ventil samtidig tilslutter en rensningskanal til det hydrauliske drev, så der ved aktivering af en omstillingsventil kan tilføres rensende hydraulikvæske i et 35 tilbageskylningsforløb fra rensningskanalen ind i DK 173620 B1 8 drevets trykkammer og ud gennem tilgangskanalen.This gives a simultaneous shut-off of the high pressure to the consumable points on the cylinder, so that the hydraulic system of the cylinder 30 is either fully active or fully switched off. Furthermore, it is possible that the pressure-controlled valve simultaneously connects a cleaning channel to the hydraulic drive, so that by activating a change-over valve, cleaning hydraulic fluid can be supplied in a backwash course from the cleaning channel into the pressure chamber of the drive and out through the inlet channel.

Opfindelsen angår endvidere et hydrauliksystem ved en cylinder i en flercylindret forbrændingsmotor, der i hver cylinder har en udstødsventil med en hydraulisk 5 aktuator med et trykkammer, der står i forbindelse med en tilgangskanal, der ved hjælp af en styreventil for aktivering af udstødsventilen periodevis er tilsluttet en højtryksledning med hydraulikvæske. Med henblik på opnåelse af de ovennævnte fordele er hydrauliksystemet.The invention further relates to a hydraulic system at a cylinder in a multi-cylinder internal combustion engine, which in each cylinder has an exhaust valve with a hydraulic actuator with a pressure chamber which communicates with an inlet channel which is periodically connected by means of a control valve for activating the exhaust valve. a high pressure line with hydraulic fluid. In order to achieve the above advantages is the hydraulic system.

10 ifølge opfindelsen ejendommeligt ved, at en trykstyret ventil har i det mindste en inaktiv stilling, hvori den forbinder afgangsporten fra styreventilen med tilgangskanalen på aktuatoren, og en aktiv stilling, hvori den forbinder tilgangskanalen med et tilbageløb, og at en 15 sekundær ledning med en omstillingsventil kan forbinde aktuatoren med en kilde for tryksat hydraulikvæske.10 according to the invention, characterized in that a pressure controlled valve has at least one inactive position in which it connects the outlet port of the control valve with the inlet channel of the actuator, and an active position in which it connects the inlet channel with a return flow and that a switch valve can connect the actuator to a source of pressurized hydraulic fluid.

Ved den kombinerede anvendelse af den trykstyrede ventil til at forbinde aktuatorens tilgangskanal og dermed trykkammeret med tilbageløbet og af omstillings-20 ventilen til at tillede tryksat hydraulikvæske til kammeret via den sekundære ledning, kan aktuatoren med tilhørende tilgangssystem for højtryksvæske væskeskylles baglæns, dvs. modsat strømningsbanen for væsketilførslen ved normal drift, hvilket giver de ovennævnte 25 fordele i form af rensning af hydrauliksystemet. Kilden for hydraulikvæske kan eksempelvis være et antal af motorens hydraulikpumper, som ved normal drift forsyner højtryksledningen, men som ved standset motor drives af en elektrisk motor til levering af en forudbestemt 30 strømningsmængde, der er afpasset til at give et passende væsketryk på eksempelvis 5-20 bar ved indstrømningen i aktuatoren. Trykket afhænger af strømningsmodstanden frem til indløbet i aktuatoren.In the combined use of the pressure controlled valve to connect the actuator inlet channel and thus the pressure chamber to the reflux and of the adjusting valve to supply pressurized hydraulic fluid to the chamber via the secondary conduit, the actuator and associated high pressure fluid supply system can be flushed backwards, ie. in contrast to the flow path for the fluid supply in normal operation, which gives the above 25 advantages in terms of cleaning the hydraulic system. The source of hydraulic fluid may be, for example, a number of the motor hydraulic pumps which supply the high-pressure line during normal operation, but which, when stopped, are driven by an electric motor to supply a predetermined flow rate adapted to provide a suitable fluid pressure of e.g. 20 bar at the flow into the actuator. The pressure depends on the flow resistance up to the inlet of the actuator.

Det foretrækkes, at omstillingsventilen forbinder 35 den sekundære ledning med et tilbageløb, når den DK 173620 B1 9 trykstyrede ventil står i inaktiv stilling, hvor cylinderen kan drives i den normale driftstilstand. Forbindelsen af den sekundære ledning til tilbageløbet, muliggør bortdræning af lækket hydraulikvaeske eller 5 returnering af brugt hydraulikvæske fra trykkammeret gennem den sekundære ledning, så en separat drænledning hertil kan undværes.It is preferred that the adjusting valve connects the secondary conduit with a return when the pressure controlled valve is in the inactive position where the cylinder can be operated in the normal operating state. The connection of the secondary conduit to the reflux allows drainage of leaked hydraulic fluid or return of used hydraulic fluid from the pressure chamber through the secondary conduit so that a separate drainage conduit thereto can be avoided.

I en udførelsesform, der navnlig er fordelagtig, hvis styreventilen er forbundet med aktuatoren gennem 10 en primær trykledning, er den sekundære ledning tilsluttet aktuatorens trykkammer via en kontraventil, der står åben for strømning ind i trykkammeret, når den sekundære ledning er tryksat af kilden for hydraulikvæske. Kontraventilen hindrer højtryksvæsken i trykkam-15 meret i at udledes gennem den sekundære ledning, når aktuatoren åbner udstødsventilen, men tillader indstrømning af rensende hydraulikvæske, når den sekundære ledning er tryksat af væske fra kilden for hydraulikvæske .In one embodiment, which is particularly advantageous if the control valve is connected to the actuator through a primary pressure line, the secondary wire is connected to the actuator's pressure chamber via a non-return valve open to flow into the pressure chamber when the secondary wire is pressurized by the source of hydraulic fluid. The check valve prevents the high pressure fluid in the pressure chamber from discharging through the secondary conduit when the actuator opens the exhaust valve, but allows the flow of purifying hydraulic fluid when the secondary conduit is pressurized by fluid from the source of hydraulic fluid.

20 I en foretrukken videreudvikling af denne udførel sesform er kontraventilen tilknyttet en sekundær kontraventil, der kun tillader væskeudstrømning fra trykkammeret til den sekundære ledning, når væsketrykket i trykkammeret er mindre end den sekundære kontra-25 ventils lukketryk. Den sekundære kontraventil står åben, når udstødsventilen er lukket, og væsketrykket i trykkammeret er lavt. I denne ventilstilling strømmer noget af hydraulikvæsken i kammeret ud gennem den sekundære kontraventil og bortledes gennem den sekun-30 dære ledning, hvorved den i væsken afsatte varme bortledes fra aktuatoren. Udstrømningsarealet af den sekundære kontraventil kan tilpasses således til den aktuelle aktuator, at den udviklede varme ved aktiveringen af udstødsventilen fjernes af den væske, der 35 strømmer ud gennem den sekundære kontraventil, mellem DK 173620 B1 10 to aktiveringer af udstødsventilen.In a preferred further development of this embodiment, the non-return valve is associated with a secondary non-return valve which only allows fluid outflow from the pressure chamber to the secondary conduit when the fluid pressure in the pressure chamber is less than the secondary pressure valve closing pressure. The secondary check valve is open when the exhaust valve is closed and the fluid pressure in the pressure chamber is low. In this valve position, some of the hydraulic fluid in the chamber flows out through the secondary check valve and is discharged through the secondary conduit, whereby the heat deposited in the liquid is discharged from the actuator. The outflow area of the secondary check valve can be adapted to the actual actuator so that the heat generated by the activation of the exhaust valve is removed by the liquid flowing out through the secondary check valve between two actuations of the exhaust valve.

Uanset om den trykstyrede ventil er beliggende ved aktuatoren eller i afstand herfra, såsom i en fordelerblok placeret i niveau under cylinderens dæksel 5 foretrækkes, at den trykstyrede ventil har en ventil-glider, der er længdeforskydelig mellem den aktive og den inaktive stilling og er påvirket i retning af den inaktive stilling af trykket ved en højtryksport på styreventilens tilgangsside og i retning af den aktive 10 stilling af en fjederkraft. En sådan længdeforskydelig ventilglider er særdeles pålidelig og virker præcist.Whether the pressure-controlled valve is located at the actuator or at a distance therefrom, such as in a distributor block located level below the cylinder cover 5, it is preferred that the pressure-controlled valve has a valve slider that is slidable between the active and inactive positions and is actuated. in the direction of the inactive position of the pressure at a high pressure port on the supply side of the control valve and in the direction of the active position of a spring force. Such a longitudinally displaceable valve slider is extremely reliable and works precisely.

Ved at lade højtrykket ved tilgangsporten til styreventilen forskyde ventilglideren til den inaktve stilling mod en fjederkraft, opnås sikker forskydning af ventil-15 glideren til den aktive stilling, når holdekraften fra højtrykket bliver mindre end fjederkraften. Fjederkraften kan variere ved forskydningen af ventilglideren, men bør i ventilgliderens inaktive stilling være såpas stor, at den med betydelig sikkerhedsmargin kan for-20 skyde ventilglideren, når højtrykket mangler. Sikkerhedsmarginen sikrer, at ventilglideren bevæges, også selv om den efter lang tids inaktivitet har tendens til at hænge fast i boringen i det tilhørende ventilhus.By letting the high pressure at the inlet port of the control valve displace the valve slider to the inactive position against a spring force, safe displacement of the valve slider to the active position is obtained when the holding force from the high pressure becomes less than the spring force. The spring force may vary with the displacement of the valve slider, but in the inactive position of the valve slider, it should be sufficiently large that it can displace the valve slider with a high safety margin when the high pressure is missing. The safety margin ensures that the valve slider is moved, even if after a long period of inactivity it tends to get stuck in the bore in the associated valve housing.

Fjederkraften på den trykstyrede ventil kan være 25 pneumatisk frembragt, eksempelvis ved at lede trykluft ind på den ene endeflade af ventilglideren. Trykluften kan eksempelvis udtages fra udstødsventilens pneumatiske fjeder, hvilket navnlig er fordelagtigt, når den trykstyrede ventil ligger på eller nær aktuatoren.The spring force on the pressure-controlled valve can be generated pneumatically, for example by conducting compressed air on one end surface of the valve slider. For example, the compressed air can be extracted from the pneumatic spring of the exhaust valve, which is particularly advantageous when the pressure controlled valve is on or near the actuator.

30 Det er også muligt at frembringe fjederkraften ved hjælp af en gasfjeder med et stempel, der er forskydelig i ventilgliderens længderetning og er monteret ud for den ene ende af ventilglideren. Stemplet er længdeforskydelig i et hovedstempel i en cylinderboring, 35 der har væsentlig mindre diameter end gasfjederens DK 173620 B1 11 cylinder for hovedstemplet, og hovedstemplet er forskydeligt i gasfjederens cylinder og har en bort fra ventilglideren vendende stempelflade, der er påvirket af trykket i et luft- eller gasfyldt trykkammer. Gas-5 fjederens cylinder er væskefyldt på den side af hovedstemplet, der vender hen mod ventilglideren. Gasfjederen har kompakt udformning og er derfor let at indbygge på det ønskede anvendelsessted, og dens stempel kan udføre stor vandring i forhold til længden 10 af gasfjederens hus, fordi stemplet er forskydeligt indsat i hovedstemplet, der selv er forskydelig i huset, så stemplerne forskydes teleskopagtigt ud og ind af huset. Stemplets store vandring gør gasfjederen særlig anvendelig i forbindelse med den trykstyrede 15 ventil med længdeforskydelig ventilglider, fordi denne glider som følge af sine store portarealer har stor vandring mellem den aktive og den inaktive stilling.It is also possible to produce the spring force by means of a gas spring with a piston which is displaceable in the longitudinal direction of the valve slider and is mounted at one end of the valve slider. The piston is longitudinally displaceable in a main piston of a cylinder bore 35 having a substantially smaller diameter than the cylinder of the gas spring for the main piston, and the main piston is displaceable in the cylinder of the gas spring and having a piston surface facing away from the valve slide which is affected by the pressure in an air - or gas-filled pressure chamber. The gas-5 spring cylinder is fluid-filled on the side of the main piston facing the valve slider. The gas spring has a compact design and is therefore easy to incorporate at the desired application, and its piston can carry large travel relative to the length 10 of the gas spring housing, because the piston is slidably inserted into the main piston which is itself slidable in the housing so that the pistons are telescopically displaced. out and in of the house. The large travel of the piston makes the gas spring particularly useful in connection with the pressure controlled valve with longitudinally displaceable valve slides, because this slider, because of its large port areas, has a large migration between the active and the inactive position.

Samtidig giver anvendelsen af tryksat gas på bagsiden af hovedstemplet den fordel, at fjederkraften oprethol-2 0 des, selv om stemplet udfører en stor udadgående vandring. Hovedstemplet holder gassen adskilt fra væsken inde i gasfjederens cylinder, og da trykket er stort set ens på begge sider af hovedstemplet, kan adskillelsen opretholdes med enkle midler, såsom ved 25 hjælp af en tætning, eller ved at tætnefladerne mellem hovedstemplet og cylinderen har passende stor længde. Lufttrykket i gasfjederen bestemmer fjederkraften, og denne kan opretholdes konstant gennem lang tid, såsom flere år, fordi hovedstemplet med den foranliggende 30 væske forhindrer gassen i at sive ud af den i gasenden lukkede gascylinder.At the same time, the use of pressurized gas on the back of the main piston gives the advantage of maintaining the spring force, even though the piston carries out a large outward travel. The main piston keeps the gas separate from the liquid inside the gas spring cylinder, and since the pressure is substantially the same on both sides of the main piston, the separation can be maintained by simple means, such as by means of a seal, or by the sealing surfaces between the main piston and the cylinder being suitably large. length. The gas pressure in the gas spring determines the spring force and this can be maintained constant for a long time, such as several years, because the main piston with the preceding liquid prevents the gas from seeping out of the gas cylinder closed at the gas end.

Den trykstyrede ventil er ikke nødvendigvis rent mekanisk trykstyret. I en udførelsesform er den trykstyrede ventil elektronisk aktiveret af signaler fra en 35 elektronisk styreenhed, der ved hjælp af en tryksensor DK 173620 B1 12 tilføres signaler om det øjeblikkelige tryk i kanalen førende til en højtryksport på styreventilens tilgangsside, hvilken styreenheden aktiverer den trykstyrede ventil til den aktive stilling, når nævnte 5 øjeblikkelige tryk er mindre end en forudbestemt grænseværdi. Den elektroniske styreenhed kan være tilknyttet cylinderen alene eller flere cylindre i fællesskab, hvor hver cylinder har en tryksensor, og den kan også være tilknyttet mindst én overordnet 10 styreenhed.The pressure controlled valve is not necessarily mechanically pressure controlled. In one embodiment, the pressure controlled valve is electronically actuated by signals from an electronic control unit which is supplied by means of a pressure sensor DK 173620 B1 12 with signals of the instantaneous pressure in the duct leading to a high pressure port on the supply side of the control valve which activates the pressure controlled valve to the active position when said instantaneous pressure is less than a predetermined limit value. The electronic control unit may be associated with the cylinder alone or several cylinders jointly, each cylinder having a pressure sensor, and it may also be associated with at least one overall control unit.

I en foretrukken udførelsesform er den trykstyrede ventil beliggende i en fordelerblok, der er placeret i lavere niveau end aktuatoren, og en primær trykledning er monteret på aktuatorens tilgangskanal og på for-15 delerblokken, fortrinsvis på dennes overside. Det er fordelagtigt at foretage afspærringen af forbindelsen til den særdeles præcist virkende styreventil i selve fordelerblokken, fordi denne er udført som en samlet enhed med indre kanaler, der ikke adskilles af motorens 20 betjeningspersonale. Hvis højtrykket til styreventilen afbrydes, eksempelvis ved hjælp af en hovedafbryderventil på styreventilens tilgangsside, sikrer den trykstyrede ventil i fordelerblokken på styreventilens afgangsside automatisk en fuldstændig afbrydelse af 25 adgangen til s tyrevent i len, så den er helt beskyttet mod forureninger. Denne udformning er både helt fejlsikker og dermed betjeningsvenlig og giver cylinderens hydrauliksystem stor driftssikkerhed.In a preferred embodiment, the pressure controlled valve is located in a distributor block located at a lower level than the actuator, and a primary pressure line is mounted on the actuator inlet channel and on the distributor block, preferably on its upper side. It is advantageous to shut off the connection to the highly precise control valve in the distributor block itself, because it is designed as a single unit with internal ducts which is not separated by the operating personnel of the engine 20. If the high pressure of the control valve is switched off, for example by means of a main switch valve on the supply side of the control valve, the pressure controlled valve in the distributor block on the outlet side of the control valve automatically ensures a complete interruption of access to the control valve in the drain so that it is completely protected from contamination. This design is both completely safe and thus easy to operate and gives the hydraulic system of the cylinder high reliability.

I en fordelagtig videreudvikling er den trykstyre-30 de ventil beliggende nær oversiden af fordelerblokken umiddelbart under den påmonterede primære trykledning.In an advantageous further development, the pressure-controlled valve is located near the top of the distributor block immediately below the mounted primary pressure line.

Da urenheder har tendens til at søge nedad, giver denne beliggenhed den bedst mulige beskyttelse af de indre kanaler i fordelerblokken.As impurities tend to search downward, this location provides the best possible protection of the internal channels in the distributor block.

35 En udførelsesform er således udformet, at kanalen DK 173620 B1 13 mellem højtryksledningen og styreventilens tilgangsport for højtryk, og fortrinsvis også kanalen fra styreventilens tankport til en returledning, passerer gennem porte i den trykstyrede ventil, der ved indstillingen 5 til sin aktive stilling afspærrer disse kanaler samtidig med afbrydelsen af forbindelsen til styreporten på styreventilens afgangsside. Styreventilen bliver dermed fuldstændig isoleret til en uvirksom, beskyttet tilstand alene ved hjælp af den trykstyrede ventils 10 omstilling til aktiv stilling.An embodiment is designed such that the channel DK 173620 B1 13 between the high pressure line and the control valve access port for high pressure, and preferably also the channel from the control valve tank port to a return line, passes through gates in the pressure controlled valve which at the setting 5 to its active position block them. channels simultaneously with the disconnection of the control port on the outlet side of the control valve. The control valve is thus completely insulated to an idle, protected state only by means of the pressure controlled valve 10 switching to the active position.

Et eksempel på en foretrukken udførelsesform for opfindelsen beskrives herefter nærmere med henvisning til tegningen, hvorpå fig. 1 viser et sidebillede af den øverste del af 15 en motorcylinder med en tilhørende hydraulisk cylinderenhed, fig. 2 et forenklet diagram over cylinderens hydrauliksystem, fig. 3 et længdesnit gennem en trykstyret ventil, 20 fig. 4 i større skala et længdesnit gennem en gasfjeder, og fig. 5 et længdesnit gennem en primær og en sekundær kontraventil.An example of a preferred embodiment of the invention will now be described in more detail with reference to the drawing, in which: FIG. 1 shows a side view of the upper part of a motor cylinder with an associated hydraulic cylinder unit; FIG. 2 is a simplified diagram of the hydraulic system of the cylinder; FIG. 3 is a longitudinal section through a pressure controlled valve; FIG. 4 shows, on a larger scale, a longitudinal section through a gas spring; and FIG. 5 is a longitudinal section through a primary and a secondary check valve.

I fig. 1 ses en cylinder 1, der er af længdeskyl-25 let type og har en udstødsventil 2 monteret centralt i toppen af cylinderen i et cylinderdæksel 3. En hydraulisk drevet aktuator 4 har et aktuatorstempel, der er nedad forskydelig i en aktuatorcyl inder, når et over aktuatorstemplet beliggende trykkammer 5 tilføres 30 højtryks hydraulikvæske. Når væsketrykket i kammeret bortledes, kan udstødsventilen lukkes igen ved hjælp af et hydraulisk drev, en mekanisk fjeder eller en pneumatisk fjeder 6 af velkendt type.In FIG. 1 is a longitudinally flush type cylinder 1 having an exhaust valve 2 mounted centrally at the top of the cylinder in a cylinder cover 3. A hydraulically driven actuator 4 has an actuator piston which is slidable downwardly in an actuator cylinder when a 30 high pressure hydraulic fluid is supplied over the actuator piston 5. When the fluid pressure in the chamber is dissipated, the exhaust valve can be closed again by means of a hydraulic drive, a mechanical spring or a pneumatic spring 6 of a well-known type.

Hydraulikvæsken til aktuatoren leveres gennem en 35 primær trykledning 7, der forbinder en tilgangskanal 8 DK 173620 B1 14 på aktuatoren med en styreport på oversiden af en fordelerblok 9, der er båret af en konsol 10. Konsollen er tilsluttet en højtryksledning 11 for hydraulikvæske, der fra en ikke vist pumpestation forsynes med hydrau-5 likvæske ved et tryk, der eksempelvis kan være beliggende i intervallet fra 125 til 325 bar. Trykket kan være fast, men er fortrinsvis regulerbart i afhængighed af motorens belastning. Pumpestationen kan forsynes fra en lagertank med hydraulikvæske, der eksempelvis kan 10 være en standard hydraulikolie, men det foretrækkes, at motorens smøreolie anvendes som hydraulikvæske, og at systemet fødes fra motorens oliesump.The hydraulic fluid for the actuator is supplied through a primary pressure line 7 which connects an inlet channel 8 DK 173620 B1 14 on the actuator with a control port on the upper side of a distributor block 9 carried by a bracket 10. The console is connected to a high pressure line 11 for hydraulic fluid which from a pump station not shown, hydraulic fluid is supplied at a pressure which may, for example, be in the range of 125 to 325 bar. The pressure may be fixed, but is preferably adjustable depending on the load of the motor. The pump station may be supplied from a hydraulic fluid storage tank, which may, for example, be a standard hydraulic oil, but it is preferred that the engine lubricating oil be used as hydraulic fluid and that the system be fed from the engine oil sump.

Forbrændingsmotoren kan være en mellemhastigheds firtaktsmotor, men er typisk en langsomtgående totakts 15 krydshovedmotor, der kan være fremdrivningsmotor i et skib eller en stationær drivenhed i et kraftværk.The internal combustion engine may be a medium-speed four-stroke engine, but is typically a slow-moving two-stroke cross-head engine which may be a propulsion engine in a ship or a stationary drive unit in a power plant.

Motoren kan udformes i forskellige størrelser med ydelser per cylinder fra 400 kW til 5500 kW, og den kan have omdrejningstal ved fuldlast beliggende i inter-20 vallet fra 50 til 600 rpm, typisk højst 200 rpm. Kryds-hovedmotoren har ingen traditionel kamaksel.The engine can be designed in various sizes with performance per cylinder from 400 kW to 5500 kW, and it can have full load rpm in the range of 50 to 600 rpm, typically at most 200 rpm. The cross main engine has no traditional camshaft.

Hver cylinder på motoren er tilknyttet en elektronisk styreenhed 12, der modtager overordnede synkroniserings- og styresignaler og afgiver elektroniske 25 styresignaler til blandt andet en styreventil 13 til aktivering af aktuatoren 4 gennem en ledning 14 og til en styreventil 15 til aktivering af en hydraulisk drevet brændselspumpe 16 gennem en ledning 17 (se fig.Each cylinder of the engine is associated with an electronic control unit 12 which receives overall synchronization and control signals and outputs electronic 25 control signals to, inter alia, a control valve 13 for actuating actuator 4 through a line 14 and to a control valve 15 for activating a hydraulically powered fuel pump. 16 through a conduit 17 (see FIG.

2). Brændselspumpens drev omfatter et drivstempel i en 30 drivcylinder 18, der er monteret direkte på fordelerblokken 9's overside 19. Fra pumpeafgangen fører trykrør 20 brændslet op til brændselsinjektorer 21.2). The fuel pump drive comprises a drive piston in a drive cylinder 18 mounted directly on the top 19 of the distributor block 9. From the pump outlet, pressure tube 20 leads the fuel up to fuel injectors 21.

Aktuatoren 4 er desuden tilsluttet en sekundær ledning 22 via en kontraventil 23 i toppen af aktua-35 toren. En drænledning 24 fra bunden af luftfjederhuset DK 173620 B1 15 er tilsluttet den sekundære ledning via en ikke vist kontraventil.The actuator 4 is additionally connected to a secondary line 22 via a check valve 23 at the top of the actuator. A drain line 24 from the bottom of the air spring housing DK 173620 B1 15 is connected to the secondary line via a non-return valve.

De relevante dele af hydrauliksystemet ved cylinderen 1 beskrives herefter nærmere med henvisning til 5 fig. 2. Fra højtryksledningen leder en afgrenet kanal 25 med et antal væskeakkumulatorer 26 den tryksatte hydraulikvæske frem til en højtryksport på tilgangssiden af styreventilen 13. En styreport på styreventilens afgangsside fører via en kanal 27 op til den 10 primære trykledning, der er monteret på blokkens overside 19. Styreventilen har endvidere en tankport, der via en kanal 28 er forbundet med et tilbageløb 29 for brugt hydraulikvæske, der kan være tilsluttet en returledning 30, hvori der er et forholdsvist lavt 15 overtryk på eksempelvis nogle få bar, eller kan være tilsluttet et dræn 31 ved atmosfæretryk, eller som vist i figuren kan ende nede i en opad åben beholder 32, der er placeret i en åben beholder 33, hvortil drænet 31 er tilsluttet. Beholderen 32 fyldes med brugt hydraulikvæ-20 ske, hvilket skaber et forholdsvist lavt, konstant overtryk i tilbageløbet. Den hydraulikvæske, som løber ovenud af beholderen 32, opsamles af beholderen 33 og løber bort i drænet 31, der kan være et rør, der fra konsollen 10 fører lodret ned til en tilslutning på 25 motorstativet, så hydraulikvæsken returneres til motorens smøreoliesump.The relevant parts of the hydraulic system at the cylinder 1 are then further described with reference to FIG. 2. From the high pressure line, a branched channel 25 with a plurality of fluid accumulators 26 directs the pressurized hydraulic fluid to a high pressure port on the inlet side of the control valve 13. A control port on the outlet side of the control valve leads via a channel 27 up to the 10 primary pressure line mounted on the upper side of the block. 19. The control valve further has a tank port connected via a duct 28 to a spent hydraulic fluid backflow 29, which may be connected to a return line 30, in which there is a relatively low overpressure of, for example, a few bars, or may be connected to a sinks 31 at atmospheric pressure, or as shown in the figure, may end up in an upwardly open receptacle 32 located in an open receptacle 33 to which drain 31 is connected. Container 32 is filled with spent hydraulic fluid, which creates a relatively low, constant overpressure in the reflux. The hydraulic fluid flowing out of the container 32 is collected by the container 33 and runs into the drain 31, which may be a pipe leading from the bracket 10 vertically down to a connection on the engine rack so that the hydraulic fluid is returned to the engine lubricating oil sump.

Når udstødsventilen skal åbnes, aktiverer et styresignal fra styreenheden 12 styreventilen 13 til den stilling, hvor højtryksporten er forbundet med 30 styreporten, så højtryksvæsken har fri adgang til den primære trykledning 7. Når udstødsventilen skal lukkes, aktiveres styreventilen til den stilling, hvor den til tilbageløbet sluttede tankport er forbundet med styreporten, så højtrykket i ledningen 10 drænes bort.When the exhaust valve is to be opened, a control signal from the control unit 12 activates the control valve 13 to the position where the high pressure port is connected to the control port, so that the high pressure fluid has free access to the primary pressure line 7. When the exhaust valve is closed, the control valve is activated to the position where it the reflux closed tank port is connected to the control port so that the high pressure in line 10 is drained away.

35 Styreventilen 13 kan være af enhver sædvanlig DK 173620 B1 16 type, såsom en enkelt, elektronisk aktiveret ventil med tre porte og to stillinger. Styreventilen kan også være opbygget af flere ventiler, såsom en elektronisk aktiveringsventil for en hydraulisk bevæget hoved-5 ventil.The control valve 13 can be of any conventional type, such as a single, electronically activated valve with three gates and two positions. The control valve may also be constructed of several valves, such as an electronic actuating valve for a hydraulically moved main valve.

En hovedafbryderventil 34 står ved normal drift i den viste åbne stilling, hvor hovedhøj tryksledningen 11 er forbundet med højtryksledningen 25 i cylinderens hydrauliksystem. Når en del af hydrauliksystemet på 10 cylinderen ønskes adskilt for eftersyn, udskiftning eller reparation, kan ventilen 34 stilles i den anden yderstilling ved manuel eller elektronisk betjening, hvorved ledningen 25 forbindes til drænet 31.In normal operation, a main switch valve 34 is in the open position shown, where the main high pressure line 11 is connected to the high pressure line 25 in the hydraulic system of the cylinder. When part of the hydraulic system of the 10 cylinder is desired to be separated for inspection, replacement or repair, the valve 34 can be set in the other outer position by manual or electronic operation, whereby the line 25 is connected to the drain 31.

Styreventilen 15 for pumpedrevet er elektronisk 15 aktiveret og har tre porte og mindst to stillinger. Den kan tilslutte en i forbindelse med ledningen 25 stående højtryksport til en styreport, der gennem en kanal 35 udmunder i fordelerblokkens overside 19 i en åbning, der står i forbindelse med trykkammeret i pumpedrevet.The pump drive control valve 15 is electronically activated 15 and has three ports and at least two positions. It can connect a high pressure port standing in conjunction with conduit 25 to a control port which opens through a conduit 35 into the upper side 19 of the distributor block in an opening communicating with the pressure chamber in the pump drive.

20 Ventilen kan have en mellemstilling, hvori alle dens porte er afbrudte. I en yderstilling er ventilens styreport forbundet med et tilbageløb, der i det viste tilfælde er en kanal 36, der er tilsluttet returledningen 30. Tilbageløbet fra styreventilen 15 kan 25 alternativt være forbundet med tilbageløbet 29 eller direkte til drænet 31. Styreventilen 15 kan eksempelvis være af den type, der er beskrevet i ansøgerens WO-94/29578.20 The valve may have an intermediate position in which all its ports are interrupted. In an outer position, the control gate of the valve is connected to a return valve, which in the case shown is a channel 36 connected to the return line 30. The return valve from the control valve 15 can alternatively be connected to the return valve 29 or directly to the drain 31. The control valve 15 may be, for example. of the type described in applicant's WO-94/29578.

En trykstyret ventil 37 er vist mere detaljeret i 30 fig. 3 og har en inaktiv stilling vist i fig. 2 og en aktiv stilling vist i fig. 3. Ventilen 37 har en længdeforskydelig dobbelt ventilglider 38, 38', hvoraf den første kontrollerer kanalen 27 fra styreventilen 13 og den anden kontrollerer kanalen 35 fra styreventilen 35 15. De to ventilglidere kan være udført i ét stykke.A pressure controlled valve 37 is shown in more detail in FIG. 3 and has an inactive position shown in FIG. 2 and an active position shown in FIG. 3. The valve 37 has a longitudinally displaceable double valve slider 38, 38 ', the first of which controls the channel 27 from the control valve 13 and the second checks the channel 35 from the control valve 35 15. The two valve slides can be made in one piece.

DK 173620 B1 17 I den øverste del af fordelerblokken forbinder et første kort kanalstykke 39 en første port 40 på ventilen med tilslutningen 41 for den primære trykledning 7, et andet kort kanalstykke 42 forbinder en anden port 43 5 på ventilen med tilslutningen 44 for den sekundære ledning 22, en kort tilgangskanal 45 forbinder en tredie port 46 på ventilen med trykkammeret i pumpedrevet, og en kort rensningskanal 47 forbinder en fjerde port 48 på ventilen med trykkammeret i pumpedrevet. De 10 fire porte på ventilen udgør alle de aktive tilslutninger for forbrugsstederne i cylinderens hydraulisk drevne elementer ved normal drift og ved strømnings-rensning. Hvis hydrauliksystemet for cylinderen ønskes udført med flere hydraulisk drevne enheder, såsom et 15 cylindersmøreapparat, kan den trykstyrede ventil 37 umiddelbart forsynes med en yderligere ventilglider af samme type som gliderne 38 og 38'.In the upper part of the distributor block, a first short duct piece 39 connects a first port 40 of the valve with the connection 41 for the primary pressure line 7, a second short duct piece 42 connects a second port 43 5 of the valve with the connection 44 for the secondary conduit 22, a short inlet duct 45 connects a third port 46 of the valve to the pressure chamber of the pump drive, and a short purge duct 47 connects a fourth port 48 of the valve to the pressure chamber of the pump drive. The four four ports on the valve make up all the active connections for the consumption points in the hydraulically driven elements of the cylinder during normal operation and during flow cleaning. If the hydraulic system of the cylinder is desired to be equipped with several hydraulically driven units, such as a cylinder lubricator, the pressure controlled valve 37 can be immediately provided with an additional valve slider of the same type as the sliders 38 and 38 '.

I den følgende beskrivelse af kanaler og porte skal nævnes, at de i figuren med punkteret streg viste 20 kanaler med tilhørende porte ikke er beliggende i det i fig. 3 viste snit, men at de for nemheds skyld er antydet, som om det var tilfældet. På den ind i fordelerblokken vendende side af den trykstyrede ventil er en femte port 4 9 forbundet med kanalen 27, en sjette 25 port 50 er forbundet med kanalen 35, en syvende port 51 er forbundet med kanalen 28, en ottende port 52 er forbundet med en første skyllekanal 53, en niende port 54 er forbundet med en anden skyllekanal 55, og en tiende port 56 er forbundet med en kanal 57 til tilba-30 geløbet 29.In the following description of channels and gates, it should be noted that the 20 channels with corresponding gates shown in the dotted line figure are not located in the one shown in FIG. 3, but for convenience, they are suggested as if they were. On the side of the pressure controlled valve facing into the distributor block, a fifth port 49 is connected to the channel 27, a sixth 25 port 50 is connected to the channel 35, a seventh port 51 is connected to the channel 28, an eighth port 52 is connected to a first flushing channel 53, a ninth port 54 is connected to a second flushing channel 55, and a tenth port 56 is connected to a channel 57 to reflux 29.

Når den trykstyrede ventil 37 står i den inaktive stilling, forbinder ventilglideren 38 den første port 40 med den femte port 49, så at kanalen 27 fra styreporten på styreventilen for udstødsventilens aktuator 35 er forbundet med den primære trykledning, og den anden DK 173620 B1 18 port 43 med den syvende port 51, så at den sekundære ledning står i forbindelse med tilbageløbet 29.When the pressure controlled valve 37 is in the inactive position, the valve slider 38 connects the first port 40 to the fifth port 49 so that the channel 27 from the control port of the exhaust valve actuator 35 control valve 35 is connected to the primary pressure line and the second port 17. port 43 with the seventh port 51 so that the secondary wire is connected to the return line 29.

Samtidig forbinder ventilglideren 38' den sjette port 50 til den tredie port 46, så at kanalen 35 fra 5 styreporten på styreventilen for pumpedrevet er forbundet med trykkammeret i pumpedrevet, og de øvrige porte på denne ventilglider er afspærrede.At the same time, valve slider 38 'connects the sixth port 50 to the third port 46 so that the channel 35 from the control gate of the pump drive control valve is connected to the pressure chamber of the pump drive and the other ports of this valve slider are blocked.

Når den trykstyrede ventil står i den aktive stilling, forbinder ventilglideren 38 den første port 10 40 med den syvende port 51, så at den primære trykledning står i forbindelse med tilbageløbet 29, og den anden port 43 med den ottende port 52, så at den sekundære ledning 22 står i forbindelse med den første skylleledning 53.When the pressure controlled valve is in the active position, the valve slider 38 connects the first port 10 40 to the seventh port 51 so that the primary pressure line communicates with the return flow 29, and the second port 43 with the eighth port 52 so that it secondary conduit 22 communicates with the first purge conduit 53.

15 Samtidig forbinder ventilglideren 38' den tredie port 4 6 med den tiende port 56, så at kanalen 45 fra trykkammeret i pumpedrevet er forbundet med tilbageløbet 29, og den fjerde port 48 med den niende port 54, så at den anden skyllekanal 55 står i forbindelse 20 med trykkammeret i pumpedrevet via rensningskanalen 47.At the same time, the valve slider 38 'connects the third port 46 to the tenth port 56 so that the duct 45 of the pressure chamber in the pump drive is connected to the backflow 29, and the fourth port 48 to the ninth port 54 so that the second flushing channel 55 is in position. connection 20 to the pressure chamber in the pump drive via the cleaning duct 47.

Et styreorgan 58 er via en kanal 59 i vedvarende forbindelse med ledningen 25, der tilfører hydraulikvæske til højtryksporten på styreventilen 37, og påvirker ventilglideren 38 med en aksialrettet kraft i retning 25 af den inaktive stilling, hvis størrelse afhænger af det øjeblikkelige tryk i højtryksporten. En gasfjeder 60 påvirker ventilglideren med en modsatrettet kraft i retning af den aktive stilling. Hvis trykket i styreventilens højtryksport af en eller anden grund bliver 30 mindre end en forudbestemt værdi, skubber gasfjederen ventilglideren 38 til den aktive stilling.A control means 58 is via a conduit 59 in continuous communication with the conduit 25 which supplies hydraulic fluid to the high pressure port of the control valve 37, and actuates the valve slider 38 with an axially directed force in the direction 25 of the inactive position, the size of which depends on the instantaneous pressure in the high pressure port. A gas spring 60 acts on the valve slider with an opposite force in the direction of the active position. If for some reason the pressure in the high pressure port of the control valve becomes 30 less than a predetermined value, the gas spring pushes the valve slider 38 to the active position.

Når den trykstyrede ventil indtager sin aktive stilling er det muligt at gennemføre en periode med rensning af et eller flere af de til fordelerblokken 35 tilsluttede delsystemer af cylinderens hydrauliske DK 173620 B1 19 system. En omstillingsventil 61 står ved normal cylinderdrift i den i fig. 2 viste stilling, hvor den afspærrer den første og den anden skyllekanal og forbinder det til højtryksledningen forbundne afsnit 5 25' af ledningen 25 med det til sty’reventilerne 13 og 15 tilsluttede afsnit 25'' af ledningen 25 med hinanden.When the pressure-controlled valve takes its active position, it is possible to carry out a period of cleaning one or more of the subsystems connected to the distributor block 35 of the hydraulic system of the cylinder DK 173620 B1 19. A switch valve 61 is in normal cylinder operation in the embodiment shown in FIG. 2, where it interlocks the first and second flushing channels and connects the section 5 25 'of the conduit 25 connected to the high pressure line with the section 25' 'of the conduit 25 connected to the control valves 13 and 15.

Omstil lings vent il en 61 kan indstilles i en anden stilling, hvor ledningen 11 via afsnittet 25' er 10 forbundet med den første skyllekanal 53, så tryksat hydraulikvæske strømmer via ventilglideren 38 op i den sekundære ledning 22, så denne tryksættes til eksempelvis 15 bar. Kontraventilen 23 hindrer ved normal cylinderdrift det gennem den primære trykledning tilførte 15 højtryk i trykkammeret i at undvige til den sekundære ledning. Når den sekundære ledning tryksættes ved hjælp af omstillingsventilen, åbner kontraventilen 23, så hydraulikvæsken strømmer baglæns gennem det hydrauliske delsystem for udstødsventilen ned gennem den primære 20 trykledning og bort gennem tilbageløbet, hvorved strømningsrensningen foretages.Switching valve in a 61 can be set to a second position where the conduit 11 is connected via the section 25 'to the first flushing channel 53, so that pressurized hydraulic fluid flows through the valve slider 38 into the secondary conduit 22, for example, to 15 bar. . In normal cylinder operation, the check valve 23 prevents the high pressure supplied by the primary pressure line in the pressure chamber from escaping to the secondary line. When the secondary conduit is pressurized by the switch valve, the non-return valve 23 opens so that the hydraulic fluid flows backwards through the hydraulic exhaust valve subsystem down through the primary pressure conduit and away through the reflux, thereby conducting the flow purge.

Omstillingsventilen 61 kan endvidere indstilles i en tredie stilling, hvor ledningen li via afsnittet 25' er forbundet med den anden skyllekanal 54, så tryksat 25 hydraulikvæske strømmer via ventilglideren 38' op gennem rensningskanalen 47 og ud i pumpedrevets trykkammer, hvor væsken hvirvles rundt og strømmer ud gennem kanalen 45 og videre bort gennem tilbageløbet samtidig med, at eventuelle urenheder rives med i 30 strømningen og fjernes.Furthermore, the switch valve 61 can be set to a third position where the line 1 is connected to the second flushing channel 54 via the section 25 ', so that pressurized 25 hydraulic fluid flows through the valve slider 38' up through the cleaning channel 47 and out into the pump drive pressure chamber where the liquid swirls and flows. out through the channel 45 and further away through the reflux at the same time as any impurities are pulled into the flow and removed.

Det er muligt at kombinere omstillingsventilen 61 og hovedafbryderventilen 34 til en enkelt ventil med flere stillinger, hvor en første stilling tillader normal cylinderdrift, hvor en anden stilling afbryder 35 den normale højtrykstilførsel med den konsekvens, at DK 173620 B1 20 det trykstyrede ventil afbryder forbindelsen til styreventilerne, hvor en tredie stilling medfører strømningsrensning af det hydrauliske delsystem for udstødsventilen, og hvor en fjerde stilling medfører 5 strømningsrensning af det hydrauliske delsystem for pumpedrevet. En sådan hovedstyringsventil for cylinderens hydrauliksystem er særdeles betjeningsvenlig.It is possible to combine the switch valve 61 and the main switch valve 34 into a single valve with multiple positions, a first position permitting normal cylinder operation, a second position interrupting 35 the normal high pressure supply with the consequence that the pressure controlled valve disconnects the connection to the control valves, where a third position causes flow cleaning of the hydraulic subsystem for the exhaust valve, and where a fourth position results in flow cleaning of the hydraulic subsystem for the pump drive. Such a main control valve for the hydraulic system of the cylinder is extremely easy to operate.

Et eksempel på udformningen af gasfjederen er vist i fig. 4. Gasfjederen påvirker ventilglideren 38' eller 10 38 ved hjælp af et stempel 62, hvis ydre ende ligger an mod enden af ventilglideren. Stemplet 62 er forskydeligt i ventilgliderens længderetning, idet gasfjederen er monteret på fordelerblokken 9 ud for den ene ende af ventilglideren med stemplet ragende ind i udboringen 63 15 for ventilglideren. Gasfjederen omfatter et hus 64 med en indre cylinder 65, hvori et hovedstempel 6 6 er længdeforskydeligt placeret. Hovedstemplet har ved begge ender en udragende krave 67, 68, der er styret af indersiden af den indre cylinder. Endvidere har hoved-20 stemplet en cylinderboring 69, der er åben i enden vendende hen mod ventilglideren 38. Stemplet 62 er længdeforskydelig i cylinderboringen 69, der har væsentlig mindre diameter end gasfjederens cylinder 65. Hovedstemplet afgrænser et luft- eller gasfyldt kammer 25 70, der kan fyldes gennem en ikke vist tilgangsstuds, der er monteret i et gevindforsynet hul 71. Et væskefyldt kammer 72 er afgrænset af hovedstemplets anden ende og af et dæksel 73 med en central boring, hvorigennem stemplet 62 passerer på tryktætnet vis. Det 30 væskefyldte kammer kan fyldes gennem en ikke vist tilslutning, der er skruet tætnende fast i et gevindhul 74. Stemplet 62 har en inde i cylinderboringen beliggende udragende krave, som udgør et stempel, der sammen med hovedstemplet afgrænser et sekundært kammer 35 75. Når hovedstemplet forskydes i retning af ventilgli- DK 173620 B1 21 deren, fordi højtrykket på den modsatte ende af glideren er faldet under den forudbestemte værdi, presses væsken i kammeret 72 ind i kammeret 75 under samtidig udskydning af stemplet 62 i en væsentlig længere 5 stempelbevægelse end flytningen af hovedstemplet.An example of the design of the gas spring is shown in FIG. 4. The gas spring actuates the valve slider 38 'or 10 38 by means of a piston 62 whose outer end abuts the end of the valve slide. The piston 62 is slidable in the longitudinal direction of the valve slider, with the gas spring mounted on the distributor block 9 off one end of the valve slider with the plunger projecting into the bore 63 of the valve slider. The gas spring comprises a housing 64 with an inner cylinder 65, in which a main piston 6 6 is longitudinally displaceable. The main piston has at both ends a protruding collar 67, 68 which is guided by the inside of the inner cylinder. Furthermore, the head 20 has a cylinder bore 69 which is open at the end facing the valve slider 38. The piston 62 is longitudinally displaceable in the cylinder bore 69 which is substantially smaller in diameter than the cylinder 65 of the gas spring. The main piston defines an air or gas filled chamber 25 70. can be filled through an inlet nozzle not shown mounted in a threaded hole 71. A liquid-filled chamber 72 is bounded by the other end of the main piston and by a cover 73 with a central bore through which the piston 62 passes in a pressure-sealed manner. The 30 liquid-filled chamber can be filled through a connection (not shown) screwed tightly into a threaded hole 74. The piston 62 has a projecting collar located inside the cylinder bore which forms a piston which, together with the main piston, defines a secondary chamber 35 75. the main piston is displaced in the direction of the valve slide, because the high pressure on the opposite end of the slider has fallen below the predetermined value, the liquid in the chamber 72 is forced into the chamber 75 while simultaneously pushing the piston 62 in a substantially longer piston movement than the movement of the main piston.

Fig. 5 viser kontraventilen, der er monteret i et ventilhus 76 på aktuatoren og har et i forhold til ventilhuset indad forskydeligt ventillegeme 77, der af en trykfjeder 78 er forbelastet i udadgående retning 10 til anlæg mod et indadvendende sæde på ventilhuset. Når den sekundære ledning 22 tryksættes forskydes ventillegemet bort fra sædet, og åbner for indstrømning af rensende hydraulikvæske til trykkammeret 5.FIG. 5 shows the check valve mounted in a valve housing 76 on the actuator and having a valve body 77 displaceable relative to the valve housing, which is preloaded outwardly 10 by a compression spring 78 to abut an inwardly facing seat of the valve housing. When the secondary conduit 22 is pressurized, the valve body is displaced away from the seat and opens for the flow of purifying hydraulic fluid into the pressure chamber 5.

En sekundær kontraventil er monteret i venti liege-15 met i en central, gennemgående boring i dette. Denne kontraventil er trykstyret og omfatter en glider 79, der er længdeforskydelig i den centrale boring og er påvirket af en trykfjeder 80 til indadgående bevægelse, indtil en krave 81 ligger an mod den udadvendende ende 20 af det stationære hus 82 for ventillegemet 77. Gliderens yderende ligger over for et plant anslag 83.A secondary check valve is mounted in the valve body in a central, through bore therein. This non-return valve is pressure controlled and comprises a slider 79 longitudinally displaceable in the central bore and actuated by a compression spring 80 for inward movement until a collar 81 abuts the outward end 20 of the stationary housing 82 of the valve body 77. The outer end of the slider is facing a flat estimate 83.

Glideren har en central gennemgående boring 84, der sætter trykkammeret 5 i forbindelse med den sekundære ledning 22, når den sekundære kontraventil står åben, 25 så der strømmer væske ud gennem glideren til ledningen 22. Diameteren af boringen i glideren bestemmer, hvor meget hydraulikvæske, der strømmer ud, mens den sekundære kontraventil står åben mellem to aktiveringer af udstødsventilen 2. Når trykket i trykkammeret stiger 30 ved indledningen af udstødsventilens aktivering, påvirker det stigende tryk i trykkammeret glideren 79 med en udadrettet, voksende kraft, som forskyder glideren udad under overvindelse af åbnekraften fra fjederen 80, indtil endefladen på kraven 81 bringes til 35 anlæg mod anslaget 83, hvorved strømningsforbindelsen DK 173620 B1 22 mellem boringen 84 og den sekundære ledning afspærres.The slider has a central through-hole bore 84 which connects the pressure chamber 5 with the secondary conduit 22 when the secondary check valve is open, 25 so that liquid flows out through the slider to the conduit 22. The diameter of the bore in the slider determines how much hydraulic fluid, flowing out while the secondary check valve is open between two actuators of the exhaust valve 2. As the pressure in the pressure chamber rises 30 at the beginning of the actuation of the exhaust valve, the increasing pressure in the pressure chamber affects the slider 79 with an outwardly increasing force which displaces the slider outwardly during overcoming of the open force from the spring 80 until the end surface of the collar 81 is brought to 35 abutment against the abutment 83, thereby blocking the flow connection DK 173620 B1 22 between the bore 84 and the secondary conduit.

Når trykket i trykkammeret 5 aflastes, skubber fjederen 80 glideren tilbage til den viste, åbne stilling.When the pressure in the pressure chamber 5 is relieved, the spring 80 pushes the slider back to the open position shown.

Det er som nævnt ovenfor muligt at placere den 5 trykstyrede ventilglider 38 og styreventilen for udstødsventilen oppe ved aktuatoren, eksempelvis monteret på dennes hus for derved at føre afgreningen fra højtryksledningen helt op til aktuatoren. Hvis cylinderes brændselspumpe er hydraulisk aktiveret, og 10 har et hydraulisk delsystem, der er beskyttet ved hjælp af en ventilglider 38' og kan strømningsrenses på den angivne måde, er det nødvendigt at anvende to gasfjedre eller på anden måde forbelaste ventilgliderne i retning af den aktive stilling. Det er også muligt kun at 15 beskytte det hydrauliske delsystem for udstødsventilen, hvilket eksempelvis kan være aktuelt, hvis brændselspumperne ikke er hydraulisk drevne.As mentioned above, it is possible to place the pressure controlled valve slider 38 and the exhaust valve control valve up at the actuator, for example mounted on the housing thereof, so as to pass the branch from the high pressure line all the way up to the actuator. If the fuel pump of the cylinders is hydraulically actuated and 10 has a hydraulic subsystem protected by a valve slide 38 'and can be flow cleaned in the manner indicated, it is necessary to use two gas springs or otherwise preload the valve slides in the direction of the active position. It is also possible to protect only the hydraulic subsystem of the exhaust valve, which may be applicable, for example, if the fuel pumps are not hydraulically driven.

Claims

A method of cleaning a hydraulic system by a cylinder of a multi-cylinder internal combustion engine having in each cylinder an exhaust valve with a hydraulic actuator with a pressure chamber which is periodically supplied to activate the exhaust valve with a high pressure hydraulic fluid from an inlet duct, characterized in that: a period of hydraulic cleaning is carried out while the hydraulic system is assembled, by connecting the inlet duct with a reflux and pressurized hydraulic fluid to the pressure chamber of the actuator from a secondary conduit.

Process according to claim 1, characterized in that the period of hydraulic cleaning is carried out on one of the cylinders of the engine while the engine is operating on the other cylinders.

Method according to claim 1 or 2, characterized in that the period of hydraulic cleaning is carried out after the hydraulic system 20 of the cylinder has been at least partially separated and reassembled.

Method according to one of Claims 1 to 3, characterized in that the periodically for supplying high pressure hydraulic fluid is controlled by means of a control valve located at the actuator, which in normal operation alternately connects the actuator chamber to a high pressure line and to the secondary line which in the normal operation, a reflux is connected and the secondary wire during the period of hydraulic cleaning is connected to a source of pressurized hydraulic fluid by means of at least one switching valve.

Method according to one of Claims 1 to 3, characterized in that the periodically for supplying high pressure hydraulic fluid is controlled by means of a control valve located at a distance from the actuator, preferably on a distributor block located in lower level than the actuator, that in normal operation the high pressure fluid from the control valve is supplied to the actuator inlet channel through a primary pressure line, and that, during the purification period, the primary pressure line is connected to a reflux and the secondary line is connected to a source of pressurized hydraulic fluid. at least one switch valve.

Method according to claim 4 or 5, characterized in that if the high pressure in an inlet port of the control valve becomes less than a predetermined value, the inlet of the actuator in the actuator is automatically connected to the reflux, preferably by means of a pressure controlled valve which in normal operation held in 15 inactive position by means of said high pressure.

Method according to claims 5 and 6, characterized in that the pressure-controlled valve is continuously loaded by a force in the direction of its active position, in which it connects the primary pressure line with the return flow.

Method according to claim 6 or 7, characterized in that an inlet channel for a hydraulic drive for a fuel pump belonging to the same cylinder as the exhaust valve is connected to the reflux 25 by means of the pressure controlled valve when it is moved to its active position and preferably connected. a cleaning channel simultaneously for the hydraulic drive.

9. Hydraulic system of a cylinder in a multi-cylinder internal combustion engine having in each cylinder an exhaust valve with a hydraulic actuator with a pressure chamber communicating with an inlet channel which, by means of a control valve for activating the exhaust valve, periodically is connected to a high pressure hydraulic fluid line, characterized in that a pressure controlled valve has at least one inactive position in which it connects the outlet port of the control valve with the inlet channel of the actuator and an active position in which it connects the inlet duct with a return line and that a secondary conduit with an adjustable valve can connect the actuator to a source of pressurized hydraulic fluid.

Hydraulic system according to claim 9, characterized in that the adjusting valve connects the secondary conduit with a return when the pressure controlled valve is in the inactive position.

Hydraulic system according to claim 9 or 10, characterized in that the secondary wire is connected to the pressure chamber of the actuator via a check valve · which is open for flow into the pressure chamber when the 15 secondary wire is pressurized by the source of hydraulic fluid.

Hydraulic system according to claim 11, characterized in that the non-return valve is connected to a secondary non-return valve which only allows liquid outflow from the pressure chamber to the secondary conduit when the liquid pressure in the pressure chamber is less than the closing pressure of the secondary check valve.

Hydraulic system according to one of claims 9 to 12, characterized in that the pressure-controlled valve 25 has a valve slider which is slidably longitudinally between the active and the inactive position and is actuated in the direction of the inactive position of the pressure at a high pressure port on the supply side of the control valve. and in the direction of the active position of a spring force.

Hydraulic system according to claim 13, characterized in that the spring force on the pressure controlled valve is pneumatically generated.

Hydraulic system according to claim 14, characterized in that a gas spring with a piston which is displaceable in the longitudinal direction of the valve slider is mounted at one end of the valve slider, that the piston is longitudinally displaceable in a main piston in a cylinder bore having substantially smaller diameter than the gas spring cylinder for the main piston, that the main piston 5 is slidable in the gas spring cylinder and has a piston surface facing away from the valve slider which is affected by the pressure in an air or gas-filled pressure chamber and that the gas spring cylinder is liquid-filled on that side of the main piston, facing the valve-10 slider.

Hydraulic system according to one of claims 9-12, characterized in that the pressure controlled valve is electronically actuated by signals from an electronic control unit which is supplied by means of a pressure sensor 15 signals of the instantaneous pressure in the duct leading to a high pressure port on the control side's supply side. and that the controller activates the pressure controlled valve to the active position when said instantaneous pressure is less than a predetermined limit value.

Hydraulic system according to one of claims 9-16, characterized in that the pressure controlled valve is located in a distributor block located at a lower level than the actuator and that a primary pressure line is mounted on the actuator inlet channel and on the distributor block, preferably on its upper side.

Hydraulic system according to claim 17, characterized in that the pressure controlled valve is located near the upper side of the distributor block immediately below the mounted primary pressure line. 3 0

Hydraulic system according to claim 17 or 18, characterized in that valve sections of the pressure controlled valve are located immediately below an inlet duct for a hydraulic drive mounted on the upper side of the distributor block for a fuel pump belonging to the same cylinder as the exhaust valve. DK 173620 B1

Hydraulic system according to one of claims 9-19, characterized in that the channel between the high pressure line and the control valve inlet port for high pressure, and preferably also the channel from the control valve tank port 5 to a return line, passes through ports in the pressure controlled valve which, when adjusted in its active state, position, these channels shut off at the same time as the disconnection of the control port on the outlet side of the control valve. 10