The cylinder sleeve of diesel engine
The present invention relates to the cylinder sleeve of diesel engine, this cylinder sleeve has the working surface of cylindrical internal surface basically, and have the oil duct that at least one inwardly opens wide, this oil duct has outside lubricant oil supply passage and at least one recess, this recess interior side opening towards cylinder.
With being connected of cylinder sleeve in, have a known problem: between the working surface of unsuitable situation lower piston ring and cylinder sleeve, produce Cylinder sticking sometimes.As if this Cylinder sticking does not produce regularly, and they may produce between the running-in period of new cylinder sleeve and in the normal work period randomly.The generation of this Cylinder sticking is assumed to be on the top that occurs in cylinder sleeve, and piston ring and working surface bear heavy load there.
In the compression stroke process of piston, the pressure of being set up is created in the piston top, and the scavenging that is provided by turbosupercharger is compressed to quite high pressure such as the 100bar pressure to 150bar from the reset pressure between for example 3bar and the 4bar in the piston head position.In the first portion of compression stroke, build-up pressure is slower, and most pressure risings can not produce till when piston just arrives its tip position.Around the piston head position, fuel valve is opened, and fuel is ejected into cylinder and lights, and is increased to maximum combustion pressure with the cylinder pressure during the after-combustion, this firing pressure for example may be in 160 and 200bar between, simultaneously the temperature on cylinder top is elevated to above 500 °.During burning, the immense pressure in the firing chamber of piston head top raises and causes that combustion gas are diffused into the annular space between piston ring groove and the piston ring, and here pressure works to the back side of ring and they is pressed against on the working surface of cylinder sleeve.High temperature during the burning also makes the viscosity of the lubricant film on the working surface diminish, so oil film is easy to break.The relatively slow danger that further increases rupture of oil film thereby piston moves around its tip position.Therefore, need on working surface, keep the Sliding velocity of piston ring oil film, relative with working surface very little.During expansion stroke, piston is pushed down, and most pressure reduces by the first half parts that occur in expansion stroke, subsequently pressure reduce relatively slow, and just at piston by before the scavenging port, pressure generally approximately is reduced to the pressure of scavenging.Therefore, compare with the pressure load on the cylinder other parts, the pressure load of cylinder head peripheral region is very big.Therefore, no matter from which point, peripheral region, cylinder sleeve top is the part of bearing the working surface of heavy load.
In the past, people carried out various effort prevent the Cylinder sticking that in the cylinder sleeve lower area, is produced be diffused into other the zone or bigger zone.DK170430 has described and has had two cylinder sleeves that are the annular notch of flute profile, these recesses interior side opening towards cylinder, and these recesses directly are arranged on the above and below of scavenging port separately.These recesses are collected the parts of lubricating oil that is promoted by piston ring downwards in the expansion stroke process, thereby prevented that Cylinder sticking is diffused on the upper area of these recesses, and this Cylinder sticking contacts with cylinder sleeve and can produce and spread by the piston skirt in the scavenging port lower zone.
JP-A6232207 discloses a kind of cylinder sleeve, this cylinder sleeve have be used to provide lubricant oil, be positioned at the entry port on cylinder sleeve top and be zigzag fashion recess shape, ring-type oil oil conservator, this oil conservator is arranged on the cylinder sleeve of the bottom 1/3rd that scavenging port goes up slightly.This recess is only towards the interior side opening of cylinder sleeve and play a part to improve lubricant oil and distribute, and piston moves downward by lubricant oil during the recess and collects and be kept in the recess, and again lubricant oil is discharged in the piston ring subsequently and goes.Because recess is a zigzag fashion, when therefore moving upward by oil conservator after piston is by the bottom position below the scavenging port, lubricant oil distributes along ring.Therefore, recess has kept lubricant oil, otherwise lubricant oil has slatterned at scavenging port.
The known embodiment of these of recess on the working surface is arranged on the bottom of cylinder sleeve, and this just means at the situation lower piston ring that does not have load basically by recess, because the pressure in the firing chamber is lower on these positions of this piston.
People know: the partial fracture of oil film can produce Cylinder sticking, thereby piston ring directly contacts with working surface, therefore formed Cylinder sticking, and Cylinder sticking causes local superheating, because heating makes the material of the cylinder sleeve of can having observed heat damage in inspection subsequently and piston ring.So far, the generation of Cylinder sticking assumes owing to lacking lubricates and caused by surperficial snap-in, and the Cylinder sticking that is carrying out duration of work causes the generation of bad heat, and heat makes material have the shank color feature of Cylinder sticking.
The objective of the invention is to design a kind of cylinder sleeve in one way,, reduce between piston ring and working surface region, producing Cylinder sticking, and the contact pressure between piston ring and the working surface is high especially in order that in the course of the work.
According to this purpose, cylinder sleeve of the present invention is characterised in that: these recesses comprise first group and second group at least, every group has two recesses at least, these recesses have the length of interruption along the circumferencial direction of cylinder sleeve, recess on these groups is arranged on the working surface length at top 15%, these recesses of not going up are on the same group arranged to be separated from each other on the cylinder sleeve longitudinal direction, and these recesses of not going up on the same group arrange with so mutual layout on the circumferencial direction of cylinder sleeve, and therefore any line on the working surface that is parallel to the cylinder sleeve axis is crossing with in these recesses at least one.
The top layout of working surface has its upper dead center at this position upper top piston ring on the lengthwise position of cylinder sleeve, working surface extends downwardly into the lower dead centre of foot piston ring.Therefore, big to go out approximately be the height of ring portion to the length of working surface than stroke.
In fact, removed the supporting zone of ring near the recess position at the working surface top in the zone with heavy load, and adopted the ring that is interrupted to support, these cause the load that encircles heavier and increased the danger of Cylinder sticking, but even now, the wearing and tearing of ring and cylinder have reduced, because recess has been interfered the formation that begins of Cylinder sticking.
Up to now, that the chances are is incorrect in the general understanding of the principal organ that Cylinder sticking is formed, because it presupposes the stationary process into progressively, this process surpasses a period of time and can cause Cylinder sticking.Unexpected, local overheated especially initiation Cylinder sticking, and unexpected, local overheated especially caused by a large amount of frictions between piston ring and the working surface, and that the result of a large amount of frictions has formed between piston ring and working surface is temporary transient, abutting edge clocklike.This bonding high combustion pressure that is created in pushed away piston ring during the expansion stroke of the oil film on the working surface.Because firing pressure also is applied to piston and piston ring to extremely big downward bump on the two, the material of being shut down on piston ring and the working surface that becomes coarse is simultaneously separated.Therefore this shutting down impelled further generation heat, produced other bonding.When piston ring passed through continuously, local Cylinder sticking may be flattened, and perhaps was diffused into the big zone of working surface.
Even in around the zone of recess, begin to form Cylinder sticking effectively arranging on the working surface on the opposite direction that piston ring moves that very narrow recess is also interfered.It is to produce bonding precondition that temperature raises.If piston ring makes rupture of oil film, so because the friction increase between ring and the working surface causes the generation of heat.Briefly, in the moment of ring by the recess on the working surface, cooling has replaced heating, because the two material of piston ring and cylinder sleeve has suitable low normal temperature, so heat constantly conducts away the position that is heated from the piston ring.Therefore, the temporary transient interruption of heat generation enough is used for preventing the formation that begins of Cylinder sticking.
Except the generation that reduces Cylinder sticking, it itself is known additional advantage that these recesses of the present invention have, the Cylinder sticking diffusion that promptly plays a part passive oil conservator and prevent to be produced.
Such position that recess is arranged on the working surface is not a simple thing, be pushed out tightly at this position upper piston ring to lean against on the working surface, and above-mentioned temperature and lubricant oil condition is in the limit.Because recess has been removed some supporting zones of ring, therefore has such danger: the distortion that by recess the time, becomes in its groove on piston, because be subjected to heavy load than thin and rubber-like rim bearing relatively.If ring has twisted, the edge by the bump recess damages it so.
According to the present invention, by means of on the circumferencial direction of cylinder sleeve, forming the recess that has discontinuity length, reach by means of arranging them in the mode that is separated from each other along the vertical of cylinder sleeve, can avoid this distortion of piston ring and cause wearing and tearing.When piston ring passes through some recesses, support it by the working surface between these recesses that remain.
These are interrupted recess is arranged to like this: any line on the working surface that is parallel to the cylinder sleeve axis intersects with a recess at least, has therefore guaranteed that any position on the piston ring circumferencial direction is by one or more cooling recesses in each stroke of piston.
Recess on these groups can form groove, and these grooves extend along the circumferencial direction of cylinder sleeve, and this just provides a kind of possibility that helps making simply cylinder sleeve.For example, these groove cuttings are become working surface or wear into working surface.
Preferably be positioned at these recesses on a group on the same lengthwise position of cylinder sleeve, this just further makes makes simply, because the location that needs during machining is less.
In addition, be preferably in the total length that these recesses on every group are 80% to the maximum along having on the cylinder sleeve circumferencial direction, preferably are 60% working surface circumference to the maximum.If along having the total length that surpasses 80% working surface circumference on the cylinder sleeve circumferencial direction, piston ring need have inappropriate high rigidity and avoids excessive distortion in piston ring groove so at these recesses on a group.If have the total length that is 60% working surface circumference to the maximum at these recesses on a group on the cylinder sleeve circumferencial direction, this will provide the satisfied of piston ring to support so, only needs two groups of recesses just can cover the whole circumference of working surface simultaneously.
At least comprise 5 recesses, preferably comprise that at least 8 recesses obtain a special advantage by means of every group, promptly by recess the time, make and avoid need balancing each other of Cylinder sticking with the needs of the distortion minimum that makes piston.With regard to 5 recesses on every group, preferably with regard to 8 recesses, the distance between the supporting zone that piston ring is along the circumferential direction gone up is little.
In addition, these recesses on every group evenly distribute along the circumference of working surface, therefore make the manufacturing of cylinder sleeve simple, and make the length minimum by the piston ring part of these recesses.
In a preferred embodiment, working surface uses for the piston ring of piston, piston ring has predetermined minimum constructive height, recess in these groups has the height also littler than the described minimum constructive height of piston ring, preferably maximum value is 75% this minimum constructive height, and suitable height is in the scope of 1-3mm.If the minimum constructive height of the aspect ratio piston ring of recess is big, when it passes through these recesses, they will hinder the sealing to the working surface of at least one piston ring so.When recess is arranged in the zone that has pressure maximum during compression and burning, this obstruction will have negative effect to the efficient of motor.If the height of recess is the minimum constructive height of 75% piston ring to the maximum, will guarantee to prevent to leak and improve the support of piston ring so effectively.Recess height between 1 to 3mm will interrupt the formation of Cylinder sticking effectively, keeps generally having the better support of the piston ring high above the 10mm ring simultaneously.
The recess that belongs to not on the same group has at interval on vertically mutually along the cylinder sleeve of 35mm at least.By this way, between concentrating, the stress on the pocket ends peripheral region of not going up on the same group can avoid the phase mutual interference.
The invention still further relates to the cylinder sleeve of diesel engine, it is columniform internal surface basically that this cylinder sleeve has, this internal surface has been formed the working surface of the piston ring on the piston, this piston ring has predetermined minimum constructive height, and have one at least and have outside lubricant oil supply passage, to the oil duct of inner opening with have one at least only to the groove of cylinder inside opening, this cylinder sleeve is characterised in that: at least one groove extends around the total inner surface of cylinder sleeve, and have a height also littler than 30% piston ring minimum constructive height, their one medium-sized along the height of cylinder sleeve on vertically of the depth ratio that these grooves directly make progress along cylinder sleeve, and be disposed on the working surface length at top 15%.
In this embodiment, have the also little height of minimum constructive height, can prevent because the distortion of the caused piston ring of synthetic wearing and tearing in piston ring groove of piston ring than 30% piston ring by means of at least one groove.Therefore, piston ring is always supported by working surface, and this working surface is positioned at the top with at least 70% the corresponding zone of height of piston ring, correspondingly, and the unsuitable distortion that can in piston ring groove, not become by groove of this piston ring.As mentioned above, these grooves have reduced the formation of Cylinder sticking.
By means of half also big groove of their height on cylinder sleeve is vertical of the depth ratio that directly makes progress at cylinder sleeve, can obtain the suitable working life of cylinder sleeve.For example, if the minimum constructive height of piston ring is 6mm, and the wearing and tearing in 1000 hours of the every work of working surface during normal smooth working are near 0.02mm, so in this case, and till these grooves will have the degree of depth of 0.6mm and will can not wear and tear down after continuous work was near 3.4 years.Usually, the marine engine design can constantly works near 2 years between each maintenance overhaul, under the sort of situation, and the deemed appropriate low limit of determined groove depth.
Each groove on the fixedly lengthwise position of cylinder sleeve along the circumferential extension of working surface.Therefore, as mentioned above, can prevent that groove from hindering piston.
In addition, can form 3 grooves at least.When these groove relative narrower of this embodiment, have to be beneficial to and arrange 3 or more a plurality of close groove mutually, stop Cylinder sticking thereby improve.
On the working surface length at top 10%, the height of the groove that the distance between these grooves may be than 8 times is little.On this nearer relatively position of working surface uppermost region, in the zone of working surface, can prevent the formation of Cylinder sticking basically with heavy load.
In second embodiment, each groove extends between the end of the cylindrical part of working surface up and down, and the minimum constructive height of the aspect ratio piston ring of this part is also little.By this way, can prevent that these grooves from hindering piston ring, the supporting zone for the same area ring of groove has increased simultaneously.
With regard to two embodiments of the invention described above, on the cylinder sleeve of coming of new, recess or groove have at least that the degree of depth of 2mm is fit to, thereby guarantee that cylinder sleeve has long working life, and do not need again machine to add recess or groove on the internal surface.
Oil duct is positioned at the below of recess or groove, thereby prevents that oily supply is subjected to the affected by high that is produced on the cylinder sleeve top.
Now,,, the present invention is described in further detail below by means of the example among the embodiment with reference to accompanying drawing, in the accompanying drawings:
Fig. 1 represents the partial side view of cylinder sleeve, local longitudinal sectional view, describes a part of piston in the figure and has been in upper dead center,
Fig. 2 has represented to have the enlarged partial view of topmost portion of the cylinder sleeve of recess on internal surface,
Second embodiment's of that Fig. 3 has represented is corresponding with Fig. 2, have recess on internal surface cylinder sleeve topmost portion enlarged partial view,
Fig. 4 is illustrated in the 3rd embodiment's of the cylinder sleeve topmost portion that has recess on the internal surface enlarged partial view with larger proportion,
Fig. 5 has represented the enlarged partial view with the 4th embodiment of corresponding, the cylinder sleeve topmost portion that has recess on internal surface of Fig. 2, and
The amplification cross-sectional view of the recess on the cylinder sleeve working surface that Fig. 6 has represented to combine with piston ring and piston.
Fig. 1 represents to be used for the cylinder sleeve 1 on the large-scale two-stroke cross head engine.According to the size of motor, can be made into the cylinder sleeve that varies in size, and this cylinder sleeve have the generally hole in 250mm arrives the 1000mm scope and the generally respective length in 100cm arrives the 420cm scope.Cylinder sleeve 1 is usually made by cast iron, and it be an integral body or be divided into mass part, these parts assemble up along mutual bearing of trend.In the segmented cylinder sleeve, it is possible forming the higher authorities' part by the steel that scribbles suitable running layer.Above-mentioned the sort of cross head engine has efficient compression ratio as 1: 16-1: 20, and this compression ratio causes heavy load on piston ring.
By means of annular, downward surface 2 are arranged on the structural housing or the top board on the cylinder body of motor, cylinder sleeve 1 is installed on the unshowned motor in known manner, subsequently, piston 3 is installed in the cylinder sleeve, cylinder cap 4 is arranged on its annular, the cylinder sleeve top on the surface 5 that makes progress, and it is fixed on the top board by means of unshowned cylinder bolt.
It is columniform internal surface basically that cylinder sleeve 1 has, and this internal surface has constituted the working surface 6 of the piston ring 7 on the piston 3.The scavenging port 8 of one annular row is arranged on the bottom of cylinder sleeve.Piston 3 moves between upper dead center and lower dead centre along the longitudinal direction of cylinder sleeve, is positioned at the hole of cylinder cap 4 at the upper surface 9 of top dead center piston, and just has been positioned at the lower end of scavenging port 8 at the upper surface of lower dead centre place piston.Working surface 6 extends to the lower limb 11 at the place, lower dead centre below of the piston ring that just is positioned at foot from the top edge 10 above the upper dead center that just is positioned at the topmost part piston ring.Waveform oil leab 12 is arranged on the internal surface of cylinder sleeve of working surface below on top 1/3rd, and lubricant oil joins working surface by entering hole 13, thus the working surface 6 on the lubricated internal surface that is positioned at cylinder sleeve.
In the zone of representing with a, this zone has constituted the working surface length at top 15%, and many recesses are arranged on the working surface 6, these recesses interior side opening towards cylinder sleeve.
Fig. 6 has represented vertical amplification view of part working surface 6 and piston 3.Piston 3 has piston ring groove 16, and piston ring 7 is arranged in the piston ring groove 16 in known manner.Piston ring groove 16 is than piston ring 7 height, and in combustion process, combustion gas are in the annular space 18 between the top cylindrical form interior surface that is diffused into the bottom of annular groove 16 and piston ring by gap 17.Because the high pressure effect of combustion gas, so elastic piston ring 7 is pushed against on the working surface 6 along direction shown in the arrow, and this working surface 6 has covered lubricant film 19, so the relative piston 3 of piston ring 7 sealings and working surface 6.Working surface 6 is furnished with recess 14, and the recess 14 in the present embodiment forms the groove of sharp-edged, but it also has rounded edge 20 in the place that carries out the transition to working surface 6.When piston moves up and down, lubricant oil is scraped in the recess 14.
The height of the aspect ratio piston ring 7 of recess 14 is much smaller, and correspondingly, when by recess 14, working surface 6 is supporting piston ring well.In second embodiment who does not illustrate, the height of the aspect ratio piston ring 7 of recess 14 is big, thereby makes gas by one or more piston rings 7 certain leakage be arranged.
If be positioned at position 22 on the outer surface of piston ring 7 by overheated, has just cooled off this position by recess 14 time so.If opposite with expectation, on the piston ring 7 position 22 and working surface 6 between formed bondingly, prevent this bonding diffusion by means of position so, by means of any main injustice place of can flattening, an edge 20 of recess by recess 14.
Fig. 2 represents the partial enlarged view of cylinder sleeve the topmost part, and in shown embodiment's view, regional a (see figure 1) has two groups of recesses 14 on working surface 6.Every group has constituted the recess that a row is flute profile 14, and this these recesses are with at interval 21 and arrange that these these recesses are along arranging perpendicular to the longitudinal axis of cylinder sleeve.These at interval 21 have formed stayed surface, and when they this surface bearing piston rings 7 during up or down by this emissions groove, so piston ring 7 can not become in annular groove and twisted.These several emissions grooves 14 arrange that along the longitudinal direction space of cylinder sleeve these grooves of going up row most are overlapping a little with these grooves of end row along circumferencial direction, and any line and one or more groove 14 that therefore are parallel on the working surface of cylinder sleeve longitudinal direction are crossing.These grooves are evenly distributed on the circumferencial direction and have identical length.For being the cylinder sleeve 1 of 700cm as diameter, every group has 11 grooves is suitable, and wherein the length of each groove is 125mm, highly is 2mm-3mm for 2mm-3mm and the degree of depth.If only adopted two groups, these grooves of going up row most are 100 to 200mm place near being positioned at apart from the uppermost margin 10 of working surface, and these grooves of end row locate to be approximately the 50mm place below being positioned at last row.Many rows have improved the effect that prevents Cylinder sticking, but the manufacturing expense of cylinder sleeve has correspondingly improved.
Fig. 3 has represented another embodiment of cylinder sleeve, and 3 groups of recesses that are flute profile 14,15 according to this embodiment are arranged on the working surface 6, and are separated from each other along the longitudinal direction of cylinder sleeve.That group of top and bottom are organized these two groups and have been formed one and arrange spaced apart groove 14, and these grooves 14 are along arranging perpendicular to the line of the longitudinal axis of cylinder sleeve.That middle group has been formed the groove that a row alternately tilts up and down.These grooves are overlapping a little along circumferencial direction, and therefore any line on the working surface that is parallel on the longitudinal direction of cylinder sleeve and one or more groove 14,15 intersect.
Fig. 4 represents another embodiment of cylinder sleeve 1, and in this embodiment, recess comprises 3 groups, and every group has the circular recess that a row is hole shape 23.These holes 23 evenly distribute and can replace mutually in a circumferential direction, and they have suitable diameter, thereby overlapping a little in a circumferential direction.
According to the present invention, word " one group of recess " is construed as sensu lato one group of recess.With reference to the embodiment of Fig. 4, when these groups were replaced along circumferencial direction mutually, every group can be regarded as 3 holes and is arranged in obliquely on the mutual below.One group of recess comprises that these are arranged in the recess on the different longitudinal position on the cylinder sleeve.
Fig. 5 represents an alternative embodiment of the invention, and in this embodiment, recess comprises 5 narrow circular troughs 24, and these grooves extend continuously around the whole circumference direction of working surface and mutually contiguous the layout.The height of groove is the minimum constructive height of 30% piston ring to the maximum, and is consistent with the schematic representation of Fig. 6 basically.These narrow grooves make when piston ring passes through groove, and can not produce this distortion that makes the edge bump groove edge of ring.
Within the scope of the invention, it is possible forming the difform recess of many kinds, and as the track of waveform track, linear or horn shape, it also is possible that different embodiments is combined.For example, if their height is less, so along the circumferential direction be provided with the recess that is interrupted closely more mutually.
The recess of working surface uppermost region or the position of groove are subjected to the influence of heavy load easily, and this position has execution to the mechanism that causes Cylinder sticking.When uppermost region did not produce Cylinder sticking, piston ring can cause Cylinder sticking hardly, because the ring load is less and further reduction on working surface.