JP2000291442A - Crosshead engine having two-cylinder rows - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crosshead engine for substantially simplifying manufacture of an engine frame box by making the engine width substantially smaller than that of a conventional engine having the same output. SOLUTION: A crosshead engine 1 is provided with two-cylinder rows 2 having the longitudinal axes 3 parallel to each other and pistons 14 connected to crossheads 16 via piston rods. The crossheads support outward facing guide surfaces 30 and inward facing guide surfaces 31 in order to guide them in the traverse direction of the engine. The inward facing guide surfaces 30 in the cylinder pair of the mutually adjacent cylinders 2 in two rows A, B are brought into contact with each other. As a result, the width of the engine can be extremely reduced, in comparison with the output.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention comprises two rows of cylinders having mutually parallel longitudinal axes and pistons connected to a crosshead by piston rods, the crosshead being in a cross engine position. A crosshead engine that holds an outwardly facing (outward facing) guide surface and an inwardly facing (inwardly facing) guide surface for guidance.

[0002]

BACKGROUND OF THE INVENTION Such an engine is described in Danish Patent 1698, describing various arrangements of pairs of parallel guideways fixedly fastened in an engine frame box.
No. 26, in which an outwardly facing guide surface and an inwardly facing guide surface on the crosshead of a cylinder pair are guided by guide surfaces both outside and inside each of the crossheads. Danish Patent Publication No. 1476/9
No. 2L describes a similar crosshead engine having two rows of vertical cylinders, the crosshead of which slides along a guide surface facing the outside and a guide surface inside the crosshead. It has an outwardly facing guide surface and an inwardly facing guide surface.

[0003]

Current types of crosshead engines are typically very large diesel-type two-stroke engines with engine heights of 4 to 15 meters,
It is not unusual to have a length of several meters and a width of 2 to 7 meters.

[0004] The large space required for such an engine desirably has a small external dimension of the engine.

[0005]

SUMMARY OF THE INVENTION In view of this object, the present invention provides that a pair of cylinders having two rows of adjacent cylinders have inwardly facing (inwardly facing) guide surfaces that are mutually adjacent. It is characterized by contact.

Surprisingly, it has been found that it is possible to have the crossheads support each other, whereby the inner guide surface can be omitted completely and the cylinder distance in the transverse direction can be reduced. . This allows for a substantially smaller engine width than the corresponding power prior art engine. Furthermore, the manufacture of the engine frame box is substantially simplified since half of the guide surface with the associated reinforcement is omitted.

[0007] The inwardly facing guide surface is located in the longitudinal center plane of the engine to provide a symmetrically configured engine. Preferably, however, the positions of the inwardly facing guide surfaces are alternately offset in the transverse direction with respect to one side and the opposite side of the vertical longitudinal midplane of the engine. For this reason, the guide surface facing inward is arranged near the end of the crosshead pin. Also, in the engine cross direction, one guide surface facing inward at one end of the crosshead pin is closest to one crosshead pin, and the other guide surface facing inward at the other end of the crosshead. Is closest to the other crosshead pin.

In one embodiment, one crosshead of the pair of cylinders has an inward facing guide surface made of steel, while the other crosshead is made of tin aluminum, bronze aluminum or PTFE. The manufacture of the engine is further simplified in that it has an inwardly facing guide surface formed in a metal matrix of a suitable white metal or another suitable bearing material. The steel surface supported by one crosshead is supported against and slides along the white metal surface, supported by the other crosshead.

The extension distance of the guide surface facing inward in the height direction of the engine can be made extremely short, and the guide surfaces can remain in contact with each other at each position of the crosshead. The length of the guide surface facing inward is at least twice the maximum height difference in the engine height direction occurring between the center lines in the crosshead of the cylinder pair during one revolution of the crankshaft. I do. This relatively long distance of the engine surface ensures that the height of the guideline associated with the other crosshead pair and the centerline of the crosshead are always equal. This means that the crosshead tilts,
At the same time, strong linear contact is prevented between the upper or lower edge of the guide surface of the inclined crosshead and the guide surface of the other crosshead.

The cylinder can be shifted in the longitudinal direction of the engine such that the two connecting rods of the cylinder pair are pivotally supported on the respective crankpins. In order to reduce the length, it is more suitable to be supported on the connecting crankpin.

[0011] In one embodiment, the crossheads of the cylinder pairs are at the same height when the crankpin is in its top position. Because the longitudinal axes of the cylinders are transversely offset with respect to the longitudinal center plane of the engine (which includes the longitudinal axis of the crankshaft), the plurality of pistons in the cylinder pair have When at its top position, it is not at its top dead center, and the piston of one cylinder passes its top dead center and performs its descending motion while the other piston is still on its way to its top dead center. Start. Thus, the two cylinders of the pair are staggered with respect to the ignition timing, and during the ignition timing, distribute the ignition power (the force generated by the ignition). The effect is that the area of the crankpin and main bearing need not be twice as large as that of a crankpin and main bearing that absorbs power from only a single cylinder. This also applies to the dimensions of the crank arm. If judged on the basis of the total power of the engine, this embodiment allows for a smaller crankshaft with a smaller bearing area and a smaller arm size, and therefore a shorter engine length. To

Acting transversely, the forces transmitted between the crossheads by the inwardly facing guide surfaces are further transmitted outward to the guide surfaces mounted in the engine frame box. This mounted guide surface absorbs forces due to both crossheads, so that the inward facing guide surfaces of the cylinder pair were mounted so as not to move within the engine frame box. Preferably, the engine is designed to have a substantially smaller area than the outwardly facing guide surface that slides along the guide surface.

In a very compact design of the engine, each of the outwardly facing guide surfaces is partially arranged between the relevant guide surface and a support bolt located inside it. As described above, the guide surface facing outward is
Since it is relatively large and the space in the height direction is limited, it is advantageous to have space for a larger area of the guide surface by extending between the support bolt and the guide surface. A further advantage at the same time is that the support bolts are self-supporting inside the guide shoe, and for each cylinder pair only four support bolts are used to tighten the cylinder part, engine frame box and bed plate together. It is good to use.

[0014] The short transverse distance between a pair of cylinders provided by the present invention can be used to further simplify engine design. Here, the cylinder pair has a connecting cylinder frame and thus a connecting chamber to which pressurized scavenging and supply air is supplied.

The engine according to the present invention is designed with more cylinders with smaller bore sizes than conventional single row crosshead engines for a given total power and a given maximum outer dimension. It is particularly suitable for driving a generator of a power plant that can be stationary. This means that the engine has a higher rotational speed (r
pm), which is advantageous for generator design and operation.

[0016]

BRIEF DESCRIPTION OF THE DRAWINGS The invention is explained in more detail below with reference to the highly schematic drawings. FIG. 1 shows a crosshead engine 1 with cylinders 2 arranged in two rows A, B (FIG. 3) and having mutually parallel longitudinal axes 3. Each of the cylinders has a cylinder liner 4 fastened to a top plate 6 of a cylinder frame 7 by cover studs and an actuator device which is mechanically actuated, for example by a camshaft or hydraulically driven and electronically actuated And a cylinder cover 8 having an exhaust valve 9 controlled by 10. Exhaust passages 11 from each of the exhaust valves pass exhaust gases into the coupled exhaust receiver 12 and the exhaust passages from the cylinder row furthest away from the exhaust receiver are connected to the cylinders in the closest row by the exhaust path. Stretch between. The exhaust gas drives the turbocharger to supply the scavenging receiving unit 13 with pressurized scavenging air and supply air. Naturally, it is also possible to use other exhaust device mechanisms such as exhaust receivers on both sides of the engine.

Each of the cylinders further comprises a piston 14 connected to a crosshead 16 via a piston rod 15, and a connecting rod 17 also
6 is connected. The cylinder rows A, B are arranged side by side at a short mutual distance L in the longitudinal direction of the engine (FIG. 2), which corresponds to the width of the lower end of the connecting rod, whereby one cylinder from each row is provided. A cylinder pair comprising cylinders is provided with a connecting crankpin 18 on which connecting rods can be mounted side by side. Alternatively, the cylinders may be arranged without any longitudinal separation, with one connecting rod having a fork-shaped lower end gripping around the lower end of the other connecting rod. However, this has the disadvantage that the engine has two different types of connecting rods. The journal 19 of the crankshaft is supported by the main bearing of the bed plate 20.

The cylinder frame 7 is common to a pair of cylinders, and keeps a state in which air is supplied from a scavenging receiving section. When the piston exposes the row of scavenging ports 21 at the lower end of the cylinder liner, air can flow into the cylinder 2. Crosshead engines, for example,
A relatively low speed two-stroke uniflow scavenging engine in the range of 60 to 400 rpm. The cylinder bore can range, for example, from 25 to 100 cm.

The cylinder frame is located on top of the engine frame box 21 'and has support bolts 2
2 mounted on the bed plate 20 together with the engine frame. As can be seen most clearly from FIG. 2, the frame box 21 'is separated by a transverse reinforcement or wall 23 between each pair of cylinders. A vertical guide surface 24 is mounted on this wall and reinforced at its outward facing rear by vertical struts 25. The guide surface with the associated struts extends along the entire height of the engine frame box.

FIG. 2 shows the crosshead mounting surface 26 for the bottom flange on the piston rod 15. In the embodiment shown, the mounting surface 26 is located on a crosshead pin 27, which is located in the crosshead bearing at the upper end 28 of the connecting rod. Alternatively, it is possible to form a crosshead having a bearing part on the piston rod and a pin on the connecting rod.

The crosshead pin 27 has crosshead shoes 29 at both ends thereof.
Support a guide surface 30 facing inward and a guide surface 31 facing outward, respectively, at positions transverse to the engine.
The outwardly facing guide surface 31 is located above the guide surface 24 and can slide along the guide surface in a manner that is entirely conventional for a crosshead engine. Guideway 3
1 is a space 32 associated between the guide surface and the support bolt.
Stretch into.

The inwardly facing guide surfaces 30 can abut each other and slide along one another during rotation of the engine when the crossheads are displaced relative to each other in the height direction of the engine. The height difference between the crossheads is greatest when in the angular position of the crankshaft illustrated in FIG. The guide surfaces 30, 31 are arranged in a vertical longitudinal plane, which in the case of an inwardly facing guide surface, corresponds to line 3
As shown by 3, it is preferably the central plane in the longitudinal direction of the engine.

FIG. 3 shows a drawing 2 together with the outline of the engine.
Two cylinder rows A, B are shown. The cylinder 2
Can be, for example, a 50 cm bore, and the engine can provide approximately 26,000 kW of power to a generator unit 34 that can generate power to the grid, for example, with 16 cylinders. For dimensional comparison, the dashed line shows the outline of an 8-cylinder crosshead engine with 70 cm cylinder bore and equivalent power.

For simplicity, the following description of the alternative embodiment shown in FIG. 4 uses the same reference numerals as described above for details of the same type. The crosshead shoe 29 is designed to be asymmetric, so that the guide surface 30 has a transverse distance s from the longitudinal center plane of the engine.
, And are shifted with respect to both sides of the center plane at both ends of the crosshead pin. Thus, the distances c1 and c2 between the center of the guide surface 30 at one end and the other end of the crosshead pin and the center of the crosshead bearing at the upper end 28 of the connecting rod, respectively, can correspond as desired. . The guide surface 30 is, for example, even if the crosshead bearings are arranged asymmetrically on the crosshead pins, for example:
They can be arranged so that the distances c1 and c2 are equal. As a result, the inward transverse force is evenly distributed to the guide surfaces at both ends of the crosshead pin.

The schematic diagram of FIG. 5 shows the relative magnitude between the transverse guidance forces between engine cycles. On the left side of the schematic, -180 ° CA indicates that the crankshaft is in the angular position where the crankpin 18 is at its lowermost position, and is where the crankpin is rotated to its top position. In an angle range of about 0 °, the piston 14 performs a compression stroke. The curve drawn with a solid line
Indicates the transverse force acting on the crosshead associated with the A-row cylinder, with positive values indicating outward force. On the other hand, the dashed curve b shows the corresponding force acting on the crosshead associated with the row B cylinder, and negative values indicate outward force. A dashed line curve c shows the generated force acting on the engine frame box, that is, the force absorbed by the guide surface 24. It can be seen that during the compression stroke, the forces acting on the crossheads in row A are relatively small, while the forces acting on the crossheads in row B are relatively large. During the expansion stroke, the situation is reversed. The generated force is near top dead center (−60 ° to + 6 °) where the crosshead is far away from the crankshaft and acts on a large torque arm.
0 °), which is advantageous in that it acts with a small torque arm when the force on the engine frame box is relatively large because the crosshead is closer to the crankshaft. It is understood that there is.

From the schematic diagram, curve a shows only small negative values, curve b shows only small positive values,
This means that the force transmitted from one crosshead to the other via the inwardly facing guide surface 30 is relatively small. Thus, the inward facing guide surface 30 may have a substantially smaller area than the outward facing guide surface 31.

The inward facing guide surface can be designed in other forms than those described above. One surface is, for example, a flat surface as described above, and the other crosshead surface is
It can be constituted by a roller rolling on a flat surface. It is further possible that these surfaces have different areas at both ends of the crosshead pin so as to compensate for the difference in force due to the eccentric position of the crosshead bearing on the crosshead pin. It is further possible to adjust the mass of the crosshead pin with the associated guide shoe so that the center of mass coincides with the center of the crosshead bearing. The support bolt may be at a position other than that shown, such as outside the guide surface or within the support bolt tube.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a crosshead engine according to the present invention.

FIG. 2 is a cross-sectional view taken along line II-II of FIG.

FIG. 3 is a schematic plan view of a cylinder of the engine of FIG. 1;

FIG. 4 is a cross-sectional view corresponding to FIG. 2 of another embodiment of the present invention.

FIG. 5 is a diagram showing a calculated guiding force during an engine cycle.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Engine 2 Cylinder 3 Parallel longitudinal axis 4 Cylinder liner 5 Cover stud 6 Top plate of cylinder frame 7 Cylinder frame 8 Cylinder cover 9 Exhaust valve 10 Actuator device 11 Exhaust passage 12 Connected exhaust receiving portion 13 Scavenging receiving device 14 Piston 15 Piston Rod 16 crosshead 17 connecting rod 18 connecting crankpin 19 journal 20 bet plate 21 'engine frame box 22 support bolt 23 transverse reinforcement / wall 24 vertical guide surface 25 vertical struts 26 mounting surface 27 crosshead pin 28 upper end of connecting rod 29 distance a between the centers of the crosshead bearing of the crosshead shoe 30 guide surface 32 space 33 line 33 C ₁ facing the guide surface 31 outward facing inwardly, C ₂ guide surface, B cylinder Row

Continuation of front page (71) Applicant 594140904 Center Syd, 161 Stamholmen, DK-2650 HVIDOVR E, Denmark

Claims (11)

[Claims] 1. A two-row cylinder having a mutually parallel longitudinal axis (3) and a piston (14) connected to a crosshead (16) by a piston rod, said crosshead (16) being provided. In a crosshead engine (1), which holds an outwardly facing guide surface and an inwardly facing guide surface for guidance in a cross-engine position, said two rows (A, B) being adjacent Said inwardly facing guide surface (30) in a cylinder pair of cylinders (2)
However, the crosshead engine is characterized in that it abuts each other. 2. The crosshead engine according to claim 1, wherein the inwardly facing guide surface (30) is arranged on a longitudinal center plane (33) of the engine. . 3. The crosshead engine according to claim 1, wherein said inwardly facing guide surface (30) is located near both ends of the crosshead pin (27), and is located at one end of the crosshead pin in a direction transverse to the engine. One of the inwardly facing guide surfaces (30) is closest to one of the crosshead pins, and the other inwardly facing guide surface (30) is at the other end of the crosshead pin. A crosshead engine that is closest to 4. A crosshead engine according to claim 1, wherein said cylinder pair comprises:
One crosshead has a steel inward facing guideway (3
0), the other crosshead having an inwardly facing guide surface (30) made of a bearing material such as white metal. 5. The crosshead engine according to claim 1, wherein the guide surface faces inward.
0) The length is at least twice the maximum difference in height between the center lines in the crosshead (16) of the cylinder pair in the height direction of the engine during one revolution of the crankshaft. And a crosshead engine. 6. A crosshead engine according to claim 1, wherein the connecting rod (17) of the pair of cylinders is pivotally supported on a connecting crankpin (18). engine. 7. A crosshead engine according to claim 1, wherein the crossheads (16) of the cylinder pairs are at the same height when the crankpin (18) is at its uppermost position. Characterized by being arranged,
Crosshead engine. 8. A crosshead engine according to claim 1, wherein an inwardly facing guide surface (30) of said pair of cylinders moves within an engine frame box (21 '). Outwardly facing guide surface (3) that slides along a non-mounted guide surface (24).
A crosshead engine having an area substantially smaller than 1). 9. A crosshead engine according to claim 8, wherein each of the outwardly facing guide surfaces (31) is between an associated guide surface (24) and a support bolt (22) arranged inside it. A crosshead engine, wherein the crosshead engine is partially disposed in the engine. 10. A crosshead engine according to claim 1, wherein the pair of cylinders has a connecting cylinder frame (7). 11. A crosshead engine (1) according to any one of the preceding claims, wherein the generator (34).
A crosshead engine, wherein the crosshead engine is in a drive connection state.