KR20060126376A - Large multi-cylinder two-stroke diesel engine - Google Patents

Abstract

A large multi-cylinder two-stroke diesel engine is provided to obtain a higher performance even though the diesel engine has the same weight and size as a conventional engine. A large multi-cylinder two-stroke diesel engine includes n or nx2 cylinders(14), n+1+x main bearings, and a crankshaft(1). The crankshaft has a main journal supported by the main bearing, and n crank throw connected to each other by the main journal. Each of the crank throw includes two arms connected to each other by a crank pin. The crank throw is connected to the main journal by a shrink connection. Each of the arms has maximum thicknesses(T1-Tnx2) in an axial direction of the crankshaft.

Description

Large multi-cylinder two-stroke diesel engine

The present invention relates to a large multicylinder two-stroke diesel engine of the crosshead type having a crankshaft assembled into a plurality of parts.

The large two-stroke crosshead diesel engine, which runs at low speed, is a large-sized device with high output power. The largest of these engines produce about 100,000 Kw at 94 rpm, with an overall length of 33 meters and a weight of nearly 3500 tons.

This type of engine of the prior art is partitioned into cylinder sections of the same axial length. This compartment is reflected in the distance between adjacent cross girder in the bedplate, the distance between adjacent transverse stiffeners in the A-type crankcase frame, and the cylinder pitch in the cylinder frame.

Such an engine includes a crankshaft, which is an assembly of a plurality of crank throws interconnected by a main journal supported by a main bearing. Each crank throw has two arms that are interconnected by a crank pin, which is coupled in a shrink connection with the associated main journal. According to the shrinkage coupling method, the end of the main journal is inserted into the bore formed in the arm. Each throw is made integrally or as an assembly of two arms and a crank pin.

The biggest engine has a throw of about 25 tonnes, and the finished crankshaft weighs up to about 400 tonnes. The crankshaft should be able to deliver peak torques up to about 12.000 KNm. The dimensions of the crankshaft parts are determined in terms of their structural dimensions, in particular the forces to be transmitted by the crankshaft and the forces generated by the vibrations of the crankshaft affect the dimensions of the respective parts. In addition, the safety factor used to determine the dimensions of the connection and the respective components is determined in consideration of the requirements required for the type of vessel.

After the shaft has been assembled, it is common for semi-built or pulley-built that the shrink pressure is limited because the material can be made to yield near the inside of the bore, i.e. near the joint, above the yield point. (fully built) A characteristic of the crankshaft. If the contraction pressure is high and deformation above the yield point occurs in the shaft material over a wider range of engine operations, it will not be possible to transmit torque without the shaft deforming beyond the permissible limits. Shrinkage pressure is a factor that is considered to securely correlate individual shaft parts, which together with the shrink surface area determine the amount of torque that can be transmitted by the shaft. As mentioned, the maximum shrinkage pressure is limited by the fact that the shaft must be dimensionally stable during operation, so when designing a shaft capable of transmitting large torques, it is necessary to increase the shrinkage surface area in existing shafts. Accordingly, it is necessary to increase the dimensions of the shaft in the axial direction and / or the radial direction.

This means that both the crankshaft and the adjacent engine parts require more space and become heavier, which in turn increases the price of the engine and lowers its efficiency.

The main journal of the crosshead type large multi-cylinder two-stroke diesel engine must be able to withstand the forces generated by the vibrating mass and the vibrations of the crankshaft as well as the large force the piston exerts on the crankshaft.

The main bearing of a large multi-cylinder two-stroke diesel engine is a slide bearing, and due to the hydrodynamic effects caused by the journal rotating in the bearing, the journal is forced to lift from the bearing face and the oil between the bearing face and the journal Pressure builds up on the film. A minimum oil film thickness must be maintained to prevent wear of the bearing face. The load acting on each of the main crankshaft bearings of a large multi-cylinder two-stroke diesel engine of the crosshead type is not uniformly distributed over each bearing, but varies from bearing to bearing. This change in load is due to the dynamic mass force that occurs when the crankshaft rotates and the vibration of the crankshaft thereby. It is the alignment between the main bearings that the crank throw, which is a non-centric part, is torsion due to the bending of the throw due to the force acting on the combustion pressure or the fluctuation of the transmitted torque. This results in poor and axial offsets, resulting in variations in the load acting on each bearing.

Large bearing surfaces are required when the maximum load acting on the bearings is increased. Thus, longer bearings must be provided for each main journal.

This means that both the crankshaft and adjacent engine parts require more space and become heavier, which in turn increases the price of the engine and lowers its efficiency.

The present invention provides a large multi-cylinder two-stroke diesel engine which is lighter and shorter than the same type of engine but has the same performance, or a large multi-cylinder two-stroke diesel engine having the same weight and size but higher performance as the conventional engine. Its purpose is to.

Cross head type large multi-cylinder two-stroke diesel in-line V- or U-engine according to the present invention for achieving the above technical problem is n or n * 2 cylinders; n + 1 + x main bearings; And a crankshaft assembled with n crank throws interconnected by a main journal each supported by the main bearings, each crank throw including two arms interconnected by a crank pin. And a main journal associated with the arm is connected to a bore formed in the arm by a shrink connection in which an end of the main journal is inserted into the bore, wherein each of the arms has a maximum thickness T in the axial direction of the crankshaft. ₁ , T ₂ , ... T _{n * 2} and the axial lengths L ₁ , L ₂ , ..., L _n of each crank throw are the highest thicknesses of the arms T ₁ , T ₂ ,. . T _{* n} is determined by the _second or at least in part, considering the maximum thickness _{T 1, T 2, ... T} n * 2, each of the shrink coupling is individually load applied to shrink the connection of engine operation Depending individually has a length _{l 1, 1 2, ...,} l n * 2 , which is determined by each of the arms up to a thickness _{T 1, T 2, ... T} n * 2 is the length l _{1, 1 2} , ..., l _{n * 2} is determined individually so that the distance D ₁ , D ₂ , ..., D _n between each of the adjacent lateral surfaces of the main bearing is It is characterized in that it is individually determined to different values according to the axial lengths L ₁ , L ₂ ,..., L _n of the crank throw positioned therebetween.

By individually setting the lengths l ₁ , 1 ₂ ,..., L _{n * 2} of the shrinkage connecting portions, the total length of the shrinking connecting portions can be made shorter. The maximum thicknesses of the arms T ₁ , T ₂ , ... T _{n * 2} are individually reduced to the minimum values such that the required length l ₁ , 1 ₂ , ..., l _{n * 2} can be included. By setting the length of most crank throws L ₁ , L ₂ ,..., L _n can be reduced. By suitably adjusting the distance D between the opposing surfaces of adjacent main bearing pairs, the distance between adjacent main bearings is reduced. Reducing the distance between the main bearings can reduce the overall length of the engine. Many large two-stroke diesel engines are used as propulsion engines for ships, especially in cargo ships, such as container ships, bulk carriers, and oil tankers, which can reduce the length of the engine and carry cargoes. It is beneficial to increase the space by a few centimeters. In addition, when the length of the engine is reduced, the weight of the engine is reduced, which is advantageous in terms of competitiveness.

The lengths l ₁ , l ₂ ,..., L _{n * 2} may be individually determined such that the maximum strain occurring in the shrinkage connection during operation of the engine is the same. Thus, the weight of the arm in the overall length of the engine can be reduced.

The axial maximum thicknesses T ₁ , T ₂ , ... T _{n * 2} and the length l ₁ , 1 ₂ , ..., l _{n * 2} are the same for two arms of the same crank throw Can be selected.

The main journal includes a bearing portion of length M ₁ , M ₂ , ..., M _{n + 1 + x} in the portion between adjacent arms, the length of which is individually in the main journal with which the engine is associated during operation. Can be determined individually depending on the load applied, the pitch between the cylinders P ₁ , P ₂ , ..., P _{(n or n * 2) -1} is the length of the main journal between the cylinders M ₁ , M _It can be determined differently according to ₂ , ..., M _{n + 1 + x} . By individually setting the length of each bearing portion of the main journal separately, it is possible to reduce the pitch of the pair of cylinders corresponding to the main journal under a higher load than other main journals. By reducing the pitch between adjacent cylinders, the overall length and weight of the engine can also be reduced.

The pitches P ₁ , P ₂ , ..., P _{(n or n * 2) -1} between the cylinders each have a maximum thickness T ₁ , T of the arm included in the crankshaft section located between the cylinders. ₂ , ... T _{n * 2} can be set individually for each.

The distance between the axial centers of adjacent pairs of the main bearings is such that the lengths of the crank throws L ₁ , L ₂ ,... L _n and the two mains accommodated by the pair of main bearings The lengths of the bearing parts of the journals M ₁ , M ₂ , ..., M _{n + 1 + x} can be determined individually.

The engine includes a bed plate including a transverse girder having a main bearing support for supporting the main bearing; And a crankcase frame formed in an A-shape by welding, the transverse stiffener supporting a guide plane for guiding the cross head, wherein the distance between transverse girders S ₁ , S ₂ , ..., S _{n - 1} are individually defined in accordance with the distance between the axial centers of the main bearings supported by the transverse girders, and the A-shape with the transverse stiffeners disposed just above the transverse girders A crankcase frame can be mounted on the bed plate.

Preferably, the dimensions of the arms other than the highest thicknesses T ₁ , T ₂ ,..., T _{n * 2} are substantially the same on all arms of the crankshaft.

The diameter of the main journal may be substantially the same for all main journals of the crankshaft.

In order to achieve the above technical problem, the present invention provides a large multi-cylinder two-stroke diesel in-line V- or U-engine of the cross head type. The engine has n or n * 2 cylinders; And a crankshaft assembled with n crank throws interconnected by n + 1 + x main journals each supported by a main bearing, each crank throw being two interconnected by crank pins. A main journal associated with the arm by means of a shrink connection in which the end of the main journal is retracted and inserted into a bore formed in the arm, the main journal having an axial end of the crankshaft. Is connected to one of the two arms, the main journal having a length M ₁ , M ₂ , ..., M _{n +1} between adjacent arms or in the portion adjacent to the arm at the axial end of the crankshaft. comprising a _{+ x} of the bearing, and the length becomes individually determined according to the load on the main journal on which the engine is associated during operation, the Between the cylinder pitch _{P 1, P 2, ...,} P (n _{or n * 2) -1} is the length of the main journals of the cylinder M _1, M _2, ..., a M _{n + 1 + x} It is characterized in that it is determined differently.

The main journal includes a bearing portion between the adjacent arms and the length of the bearing portion can be determined individually according to the load applied individually to the main journal associated with the engine being operated, and the pitch P ₁ between the cylinders. , P ₂ , ..., P _{(n or n * 2) -1} can be defined differently depending on the length of the bearing part of the main journal between the cylinders. By individually setting the length of each bearing portion of the main journal separately, it is possible to reduce the pitch of the pair of cylinders corresponding to the main journal under a higher load than other main journals. By reducing the pitch between adjacent cylinders, the overall length and weight of the engine can also be reduced.

The length of the bearing portion of the main journal can be determined individually to obtain the lowest possible value.

The engine includes a bed plate including a transverse girder having a main bearing support for supporting the main bearing; And a crankcase frame formed in an A-shape by welding, the transverse stiffener supporting a guide plane for guiding the crosshead, wherein the distance between the transverse girders S ₁ , S ₂ , ..., S _{n - 1} can be individually determined in accordance with the distance between the axial centers of the main bearings supported by the associated transverse girders, with the transverse stiffeners disposed directly above the transverse girders The A-shaped crankcase frame can be mounted on the bed plate.

The objects, features and characteristics of the large two-stroke diesel engine according to the invention will be more clearly understood by the following detailed description.

Hereinafter, a cross head type large two-stroke diesel engine according to an embodiment of the present invention will be described in detail.

1 and 2 show a large low speed two stroke cross head diesel in-line engine 10 with a piston diameter of 98 cm that can be used as a prime mover of a marine propulsion engine or power plant. Such engines typically have six to sixteen arranged cylinders. 1 shows a side view of an eight-cylinder engine 10 and further shows the outline of a homogeneous engine of 9, 10, 11, and 12 cylinders. Below the engine 10 a scale in meters is provided to indicate the absolute size of the engine, which is about 18 meters in length for an 8 cylinder engine and about 28 meters in length for a 14 cylinder engine.

The engine 10 stands on a bed plate 11 with a main bearing for supporting the crankshaft 1. The bed plate 11 is manufactured by dividing into sections of appropriate sizes according to the production equipment. Bed plate 11 is composed of girders (longitudinal) welded girders (girder) and crosswise welded girders 31 (see Fig. 4), the transverse girders 31 are cast steel ( cast steel) main bearing support 32 is provided.

Referring to the hidden line of FIG. 2, the engine 10 includes a piston 28 connected to the cross head 24 via a piston rod 29. The cross head 24 is guided by the guide plane 23. The connecting rod 30 connects the cross head 24 to the crank pin of the crank shaft 1.

An A-shaped crankcase frame 12 formed by welding is mounted to the bed plate 11. The cylinder frame 13 is mounted on the top of the crankcase frame 12. Staybolts 26 (see FIG. 3) are coupled to the bed plate 11 and the cylinder frame 13 and maintain their mating structure. The cylinder 14 is accommodated in the cylinder frame 13. The exhaust valve assembly 15 is mounted on top of each cylinder 14. The cylinder frame 13 also houses a fuel injection system 19, an exhaust gas receiver 16, a turbocharger 17, and a scavenge air receiver 18.

Referring to FIG. 3, a stiffener provided in the form of a transverse plate 21 formed in a transverse direction in the crankcase frame 12 is disposed correspondingly between each cylinder. The transverse plate 21 interconnects the outer wall 22 of the crankcase frame 12 extending in the longitudinal direction and is formed from the top to the bottom of the A-type crankcase frame 12 to be cranked. The lateral rigidity of the case frame 12 is enhanced.

The vertical guide plane 23 for receiving the transverse force acting on the cross head 24 (see FIG. 2) is mounted to the transverse plate 21 by, for example, welding or the like. The rear side of each guide plane 23 is supported by an additional wall 25 extending vertically connecting the guide plane 23 and the transverse plate 21. The guide plane 23, the additional wall 25, and the transverse plate 21 form a hollow profile with high torsional stiffness and receive the stay bolt 26.

Referring to FIG. 4, a cross girder is formed across the bed plate 11 in the form of a through going plate 31 in the bed plate 11. The main bearing support 32 is mounted to the transverse girder 31 by, for example, welding. The lower bearing cell 33 is housed in the main bearing support 32. The main bearing further comprises an upper bearing cell and a bearing cap (not shown) which are coupled to the main bearing support 32 after the crankshaft 1 is placed on the bed plate 11.

5A shows the crankshaft 1 of a conventional 12 cylinder engine. 5d shows a crankshaft according to a preferred embodiment of the present invention. 5b to 5c are views applied to both a conventional crankshaft and a crankshaft according to a preferred embodiment of the present invention. The crank throw / cylinder is numbered from 1 to 12, the first crank throw is located at the front end of the crank shaft 1 and the twelfth crank throw is located at the leading end (rear end) of the crank shaft 1. For engines with other numbers of throws, the number of throws is represented by "n". The number of cylinders is n for in-line engines and n * 2 for U- or V-engines (not shown).

Since there are few cranes that can lift the finished crankshaft 1 weighing about 400 tons, the crankshaft 1 is fitted by assembling the front end 1b and the rear end 1a. Each of the crankshaft parts 1a, 1b comprises 6 of a total of 12 crank throws 2 (other combinations are possible, for example with 4 throws each for a 14 cylinder engine crankshaft). Two parts and one part with six throws). The front end 1b and the rear end 1a are lowered into each bearing cell 33 one by one using the main journal 5. The front end 1b and the rear end 1a are assembled in the longitudinal direction at the flange connecting portion 37. After the front end 1b and the rear end 1a are connected by bolting the flanges of the flange connection part 37 with the bearing caps attached thereto, the crankcase frame 12 is placed on the bed plate 11. It becomes possible.

Each of the crankshaft parts 1a, 1b is assembled using six (n / 2) crank throws 2 and seven (n / 2 + 1) main journals 5. The crank throw 2 has two arms 3 and a crank pin 4 formed integrally therewith. The crank throw 2 is integrally formed using cast or forged steel. The six crank throws 2 of each of the crankshaft parts 1a, 1b are connected to each other by the main journal 5. Thus, the total number of main bearings in the finished crankshaft is 14 (n + 1 + x), where x is the variable that determines the number of main bearings in the assembled crankshaft, and the crankshaft parts and connections are designed. The value is determined by the method. Since there are no flange connections designed to increase the total number of main bearings, the total number of main bearings is determined by the number of flange connections. As a result, the value of the variable x is 1 for the illustrated crankshaft.

The rear end 1a is provided with a thrust bearing 39 to withstand the forces generated by the propeller driven through an intermediate shaft (not shown).

FIG. 5B shows the angular distribution of each of the throws 2 of the front end 1b as an axial view of the crankshaft.

FIG. 5C shows the angular distribution of each of the throws 2 of the rear end 1b as an axial view of the crankshaft.

The main journal 5 has two end sections and a center that shrink fit into a bore formed in the arm 3 of the adjacent crank throw 2 when the crank shaft 1 is assembled. It includes a bearing portion. Each of the main journals 5 located at both ends of the front end 1b and the rear end 1a includes one end which is shrink-inserted into the bore formed in the bearing 3 and the arm 3 of the associated crank throw 2. do.

Referring to FIG. 6, in the crank throw 2 of the cylinder 1, a shrink connectin between the arm 3 and each journal 5 is shown in detail. The contractive connection is made over the length l ₁ in the arm 3 (l ₃ and l _{4 for} the crank throw of the second cylinder, l _{3 for} the crank throw of the cylinder _3, etc.). The torque that can be transmitted by the contractive connection is determined by the contact pressure, the diameter of the bore, and the length l ₁ , l ₂ , ..., l _{n * 2} (n = number of throws of the engine). That is, the greater the length and diameter, the greater the torque can be transmitted. Safety factors, which are usually taken into account when dimensioning shrinkage connections, are chosen to meet the requirements of each type of vessel.

The axial lengths l ₁ , l ₂ , ..., l _{n * 2} of the contractive connection are mainly determined by the axial widths T ₁ , T ₂ , ..., T _{n * 2} of the respective arms 3. . The maximum pressure depends on the excess diameter of the main journal 5 exceeding the inner diameter of the bore and the structural strength and stability around the bore of the material constituting the arm 3. The structural strength of the material around the bore depends on the thickness of the material layer surrounding the bore and the properties of the material. Typically, all parts of the crankshaft 1 are made of high tensile steel. These parts can be manufactured by post-treatment and precision machining of materials formed by forging or casting to have the desired material properties and surface quality.

The maximum torque that must be transmitted by the length l ₁ , l ₂ , ..., l _{n * 2} of each shrinkage connection during engine operation is not the same for all couplings. At a given point in time, the cylinder in the combustion stroke contributes to the peak value of the torque transmitted in the part of the crankshaft 1 between the cylinder and the output end of the crankshaft 1. In a 12-cylinder two-stroke engine, six cylinders are simultaneously in a combustion stroke at any given point in time. Thus, in the case of the crankshaft 1 of a large two-stroke engine, the torque transmitted at the portion near the output end (rear end) is considerably larger than the torque transmitted at the portion near the front end. In addition, since the dynamic torsion and oscillation affect the distribution of the maximum torque load of each contractive connection, the length of the contractive connection l ₁ , l ₂ , ..., l _{n * 2} It does not increase linearly from the front end to the rear end of (1). The maximum torque delivered by each shrink connection can be determined numerically, analytically, experimentally, or by combining these methods. The lengths l ₁ , l ₂ , ..., l _{n * 2} are determined in this way such that the safety factor is substantially the same for all the shrink connections of the crankshaft. For practical reasons, the lengths for the same main journal (5) among the lengths of the shrinkage connections l ₁ , l ₂ , ..., l _{n * 2} are given by l ₂ = l ₃ , l ₄ = l ₅ , l ₆ = l ₇ The same may be selected. This is because the torque delivered by these two contractive connections is generally the same.

The required length l ₁ , l ₂ , ..., l _{n * 2} for the shrink connection is the axial thickness T ₁ , T ₂ , ..., T _n of the arm 3 of each crank throw 2 _It is a common determinant when sizing _{* 2} . Generally, the axial thicknesses T ₁ , T ₂ , ..., T _{n * in} order to ensure the space of the rounded transition 39 to reduce the stress between the main journal 5 and the crank arm 3. ₂ is slightly larger than the lengths l ₁ , l ₂ , ..., l _{n * 2} required for the shrink connection.

In a preferred embodiment of the invention, the dimensions other than the highest thicknesses T ₁ , T ₂ ,..., T _{n * 2} in the arm 3 are substantially the same in all arms of the crankshaft 1.

According to another embodiment of the invention, which is not shown, the crank arms are divided into groups of sets so that arms having the highest axial thicknesses T ₁ , T ₂ , ..., T _{n * 2} are the same group. And the highest thickness may allow T ₁ , T ₂ , ..., T _{n * 2} to vary from group to group.

Since a relatively small torque is transmitted in the case of a multicylinder engine, the front end of the crankshaft typically includes a group of arms 3 with relatively small maximum thicknesses T ₁ , T ₂ ,..., T _{n * 2} . Since the torque transmitted from the rear end of the multi-cylinder engine is relatively large, the rear end of the crankshaft includes arms 3 of the group with relatively large maximum thicknesses T ₁ , T ₂ , ..., T _{n * 2} . can do.

FIG. 5D shows the crankshaft individually determined in accordance with the torque transmitted during the engine operation with the length l ₁ , l ₂ ,..., L _{n * 2} . As can be seen when comparing the conventional crankshaft shown in FIG. 5A and the crankshaft according to the preferred embodiment of the present invention shown in FIG. 5D, the overall length of the crankshaft according to the preferred embodiment of the present invention has been considerably reduced. As a result, the overall length of the engine 10 can be reduced. The practical reason for this reduction is that the lengths of the shrinkage connections l ₁ , l ₂ , ..., l _{n * 2} are determined individually.

7 shows a part of the front end 1b in more detail. Here, the axial thickness (T _3), the second axial thickness of the arms (3) of the crank throw (2) associated with the cylinder (T ₂₎ of the arm (3) of the crank throw (2) combined with a three cylinder Larger than the axial thickness T ₁ of the arm 3 of the crank throw 2 associated with the first cylinder. Since the radial load applied to the crank pin bearing is normally distributed evenly over all the crank pins 4, the lengths of all the crank pins 4 are the same in this embodiment. Therefore, according to the lengths L ₁ , L ₂ , ..., L _n of the individually determined crank throws ₂ , the distances D ₁ , D ₂ , ..., D _n between the sides of adjacent main bearing pairs are respectively the minimum values. Can be adjusted (see FIG. 4).

The main journal 5 located between the two crank arms 3 has two end portions inserted in the bores formed in each of the two crank arms 3. Each main journal 5 located at the end of the front end 1b and the end of the rear end 1a of the crankshaft 1 has one end inserted into the bearing of the bearing portion and the bore of the crank arm 3. It includes. The length of the end of the main journal 5 is individually determined to fit the length l ₁ , l ₂ ,..., L _{n * 2} of the shrinkage connection. The main journal 5 comprises bearing parts with individually defined lengths M ₁ , M ₂ ,..., M _{n + 1 + x} (see FIGS. 6 and 7). The main bearing support 32 and the bearing cell 33 have correspondingly set axial lengths separately (see FIG. 4).

The radial load on the main bearings is not evenly distributed. This non-uniform distribution is due to the radial oscillation of the crankshaft and the warping deformation of the crankshaft. Warping deformation of non-centric components of the crankshaft 1, such as crank throw 2, causes radial offset, which affects the radial load distribution of the main bearing. The maximum radial load that each main bearing can withstand can be determined by numerical methods, analytical methods, experimental methods, or a combination thereof. As a result, the axial lengths M ₁ , M ₂ ,..., M _{n + 1 + x} of the bearing portion and the axial lengths of the bearing cells 33 are determined.

In order to further reduce the weight of the engine, the material thicknesses G ₁ , G ₂ , ..., G _{n + 1} of the main bearing support 32 can be individually determined according to the load applied to each main bearing during engine operation. have.

Cylinder pitches P ₁ , P ₂ , ..., P _{(n or n * 2) -1} between adjacent cylinders are axial lengths M ₁ , M ₂ , ..., M _n Individually determined by _{+ 1 + x} and the axial thicknesses T ₁ , T ₂ , ..., T _{n * 2} of the crank arm (3).

The distances S ₁ , S ₂ ,..., S _n-1 between the centerlines of adjacent pairs of lateral girders 31 (see FIG. 4) for receiving the main bearing support 32 are located between them. It is adjusted to the axial length of the throw 2 and the axial lengths M ₁ , M ₂ ,..., M _{n + 1 + x} of the bearing portion.

The transverse stiffeners 21 (see FIG. 3) are placed directly above the transverse girders 31 for stability, and thus between adjacent pairs of transverse stiffeners 21 (see FIG. 3). The distances S ₁ , S ₂ , ..., S _n-1 are the distances S ₁ , S ₂ , ..., S _n- between pairs of transverse girders 31 (see FIG. 4) located below them. Same as ₁

The distance between the cylinder pitches P ₁ , P ₂ , ..., P _{(n or n * 2) -1} and the transverse stiffener 21 S ₁ , S ₂ , ..., S _n-1 is the cylinder frame ( 13) (see FIGS. 1 and 2) the same. Thus, in the finished engine 1 the axial sections are individually of defined length. As a result, the overall length of the engine 10 according to the invention can be reduced by 3 to 7% as compared to conventional engines. When the length of the engine 10 is reduced, the weight is significantly reduced.

Although the embodiments of the present invention have been described in detail above, it should be considered from an illustrative point of view rather than a restrictive point of view, and a person of ordinary skill in the art to which the present invention pertains does not depart from the essential characteristics of the present invention. It will be appreciated that it can be implemented in a modified form.

As described above, the engine of the present invention is lighter and shorter than conventional engines of the same type, and has the same performance, or has the same performance and weight as the conventional engines but has higher performance.

The features and advantages of the present invention may be better understood with reference to the following accompanying drawings in conjunction with the following detailed description of embodiments of the invention, of which:

1 is a side view of a conventional large 8-cylinder two-stroke diesel engine with the lengths of a 9-12 cylinder engine;

2 is a front view of the engine shown in FIG. 1;

3 is a cross-sectional view of the crankcase frame;

4 is a cross-sectional view of the bed plate;

5A is a side view of a conventional crankshaft for a 12 cylinder engine;

5B is an axial view of the crankshaft front end shown in FIGS. 5A and 5D;

5C is an axial view of the crankshaft rear end shown in FIGS. 5A and 5D;

5D is a side view of a crankshaft of a twelve-cylinder engine in accordance with one embodiment of the present invention;

FIG. 6 is a detailed cross-sectional view of the crank throw and main journal portion of the crankshaft shown in FIG. 5D; FIG. And

FIG. 7 is a partially enlarged view of the crankshaft shown in FIG. 5D.

Claims (17)

In the large multi-cylinder two-stroke diesel in-line V- or U-engine 10 of the crosshead type, n or n * 2 cylinders 14; n + 1 + x main bearings; And And a crankshaft (1) assembled with n crank throws (2) interconnected by a main journal (5) each supported by the main bearings, Each crank throw 2 comprises two arms 3 interconnected by crank pins 4, the ends of the main journal 5 being shrink-inserted into the bores formed in the arms 3. The main journal 5 associated with the arm 3 is connected by a shrink connection, Each of the arms 3 has a maximum thickness T ₁ , T ₂ ,... T _{n * 2} in the axial direction of the crankshaft ₁ and the axial length L ₁ , of the respective crank throw 2. L ₂ , ..., L _n is defined by the highest thicknesses T ₁ , T ₂ , ... T _{n * 2} of the arm 3, or at least partially, by the maximum thicknesses T ₁ , T ₂ , ... Is determined in consideration of T _{n * 2} , and each of the contractive connections has a length l ₁ , 1 ₂ ,..., _{N n * 2} which is individually determined according to the individual load applied to the contractive connection during engine operation. The highest thicknesses T ₁ , T ₂ , ... T _{n * 2} of each of the arms 3 are individually determined such that the length l ₁ , 1 ₂ , ..., l _{n * 2} can be included and the main The distances D ₁ , D ₂ , ..., D _n between each adjacent pair of lateral surfaces of the bearing are the axial lengths L ₁ , L ₂ , of the crank throw 2 located therebetween. ., a different value individually determined according to L _n Engines characterized by that. The method of claim 1, The length l ₁ , l ₂ ,..., L _{n * 2} are each individually determined such that the maximum strain occurring at the shrinkage connection during operation of the engine 10 is the same. Engine made. The method according to claim 1 or 2, The axial maximum thicknesses T ₁ , T ₂ ,... T _{n * 2} and the length l ₁ , 1 ₂ , ..., l _{n * 2} of the shrinkage connection are joined to the same main journal 5. An engine characterized by the same for the arm (3). The method according to any one of claims 1 to 3, The main journal 5 has a length M ₁ , M ₂ ,..., M _{n +} between adjacent arms 3 or a portion adjacent to the arm 3 at the axial end of the crankshaft ₁ . _A bearing part of _{1 + x} , the length of the bearing part being individually determined according to the load applied to the main journal 5, which is associated with the engine 10 during operation, and the pitch P between the cylinders 14; ₁ , P ₂ , ..., P _{(n or n * 2) -1} is the length M ₁ , M ₂ , ..., M _{n + 1 + x} of the main journal 5 between the cylinders 14. The engine, characterized in that differently determined according to. The method of claim 4, wherein Each of the pitches P ₁ , P ₂ ,..., P _{(n or n * 2) -1} between the cylinders 14 is an arm included in a crankshaft section located between the cylinders 14. Engines characterized by the highest thicknesses of 3) T ₁ , T ₂ , ... T _{n * 2,} respectively. The method according to claim 4 or 5, The distance between the axial centers of adjacent pairs of the main bearings is determined by the lengths l ₁ , l ₂ ,..., L _{n * 2 of} the crank throws 2 between them and the pair of main bearings. An engine characterized in that it is individually adapted to the lengths M ₁ , M ₂ , ..., M _{n + 1 + x} of the bearing parts of the two main journals (5) that are received. The method of claim 6, A bed plate (11) comprising a transverse girder (31) having a main bearing support (32) for supporting said main bearing; And It further comprises a crankcase frame (12) formed in an A-shape by welding, comprising a stiffener (21) supporting a guide plane (23) for guiding the cross head (24), The distances S ₁ , S ₂ ,..., S _n-1 between the transverse girders 31 are individually determined in accordance with the distance between the axial centers of the main bearings supported by the transverse girders 31, and the transverse An engine characterized in that the A-shaped crankcase frame (12) is mounted on the bed plate (11) with a directional stiffener (21) disposed just above the lateral girder (31). The method according to any one of claims 1 to 7, An engine characterized in that the dimensions of the arms (3) other than the highest thicknesses T ₁ , T ₂ ,..., T _{n * 2} are substantially the same at all arms (3) of the crankshaft (1). The method according to any one of claims 1 to 8, An engine, characterized in that the diameter of the main journal (5) is substantially the same for all main journals (5) of the crankshaft (1). The method according to any one of claims 1 to 9, The dimensions of each of the main bearing supports (32) are individually determined according to the load on the main bearings to which the engine is concerned during operation. The method of claim 10, The dimensions of the main bearing support (32) is characterized in that the engine is individually determined by changing the thickness of the material. The method according to any one of claims 1 to 11, The crank arm 3 has the same axial maximum thicknesses T ₁ , T ₂ , ..., T _{n * 2} in one group and different maximum thicknesses T ₁ , T ₂ , ..., T _n between different groups. An engine characterized by being grouped in units of sets to have _{* 2} . The method of claim 12, The front end of the crankshaft comprises an arm (3) belonging to a group having a relatively low axial maximum thickness T ₁ , T ₂ ,..., T _{n * 2} . The method according to claim 12 or 13, The rear end of the crankshaft comprises an arm (3) belonging to a group having a relatively high axial maximum thickness T ₁ , T ₂ ,..., T _{n * 2} . In the large multi-cylinder two-stroke diesel in-line V- or U-engine 10 of the crosshead type, n or n * 2 cylinders 14; And A crankshaft (1) assembled with n crank throws (2) interconnected by n + 1 + x main journals (5) each supported by a main bearing, Each crank throw 2 includes two arms 3 interconnected by a crank pin 4 and a contraction in which the end of the main journal 5 is inserted into a bore formed in the arm 3. A main connection 5 associated with the arm 3 is connected by a shrink connection, the main journal 5 of the two arms 3 at the axial end of the crankshaft 1. Connected to one, the main journal 5 has a length M ₁ , M ₂ , .. between the adjacent arms 3 or a portion adjacent the arm 3 at the axial end of the crankshaft ₁ . .., M _{n + 1 + x} bearing parts, the length of which is determined individually according to the load on the main journal 5 associated with the engine 10 during operation, and the pitch between the cylinders 14. P ₁ , P ₂ , ..., P _{(n or n * 2) -1} is the length M ₁ , M ₂ , ..., M _{n +1+} of the main journal 5 between the cylinders 14. _The engine characterized in that it depends on _x . The method of claim 15, The length of the bearing part M ₁ , M ₂ , ..., M _{n + 1 + x} is individually determined to obtain the smallest possible value. The method according to claim 15 or 16, A bed plate (11) comprising a transverse girder (31) having a main bearing support (32) for supporting said main bearing; And It further comprises a crankcase frame (12) formed in an A-shape by welding, comprising a stiffener (21) supporting a guide plane (23) for guiding the cross head (24), The distances S ₁ , S ₂ ,..., S _n-1 between the transverse girders 31 are individually determined in accordance with the distance between the axial centers of the main bearings supported by the associated transverse girders 31, The engine characterized in that the A-shaped crankcase frame (12) is mounted on the bed plate (11) with the transverse stiffener (21) disposed directly above the transverse girder (31).