JPH07324630A - Optimizing method of ignition angle of in-line engine and in-line engine - Google Patents

Abstract

PURPOSE: To optimize the ignition angle by bringing the first-grade and the second-grade inertial force into an independent state in the manner reducing oscillation parameter of an engine. CONSTITUTION: An in-line engine 1 involves a plurality of cylinders having pistons 7 respectively connected to crank throws linked on a shared crankshaft 12. The crank throw is positioned at a prescribed angle position corresponding to the ignition angle of a cylinder and adjusted to at least two different values within the angle difference (αj -αj-1 ) between the ignition angles of the cylinders ignited successively. At this time, the first-grade inertial force of the engine 1 is brought into a non-equilibrium state and, if the mass in reciprocating motion of a cylinder is equal, the second-grade inertial force is brought into an unequilibrium state. At least two cylinders are then adjusted so as to be different from the mass in reciprocating motion of other cylinders, therefore the first-grade inertial force is brought into an equilibrium state. It is thus possible to reduce the selected oscillation parameter and bring the first- and second-grade inertial forces into an independent state for optimizing an ignition angle (α).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention has several cylinders each having a piston connected to an associated crankthrow on a common crankshaft, the crankthrow having a predetermined angle corresponding to the ignition angle of the cylinder. Positioned in position, at least two of the angle differences between the cylinder firing angles that are successively fired have different dimensions, each cylinder including at least the mass of the piston and the mass of a portion of the connecting rod. A method for optimizing ignition angle in an in-line engine, such as a marine main engine, including a reciprocating engine component having an associated reciprocating mass.

[0002]

2. Description of the Related Art Considering the force relationship for a single cylinder of such an engine, the inertial force of the first class is substantially larger than the inertial force of the second and higher classes. Normally, for engines, it is necessary to balance the primary and secondary inertial forces created by the reciprocating masses of all cylinders (ie cancel all forces acting in the vertical direction to zero). Is believed to be.

Inertial forces are generated in each cylinder, and therefore these inertial forces are generated at positions separated from each other in the longitudinal direction of the crankshaft. It is usually possible to obtain a balanced force, but in the case of engines with a large number of cylinders, the moments of equilibrium at the same time can only be obtained in special cases. Therefore, the free moments (external moments) are either individual moment compensators (configured as separate units mounted on the engine or remote from the engine) or of a special shaft device for vibration damping. It is so large that it needs to be used. Most prior art methods and apparatus that attempt to mitigate the adverse effects of the engine's free moments are expensive and have complicated engine and associated mechanism structures.

The magnitude of the free force or free moment in a two-stroke inline engine depends on the ignition angles, which are usually able to balance the primary and secondary inertial forces of the cylinder. Thus, the angular difference between the ignition angles for the cylinders that are continuously ignited is determined by "360 ° / (number of cylinders)".

US MI Press Corporation (MIT P
Ress) published in 1985 by CF Taylor, "The Internal-Combustion Engine in
Theory and Practice) 2nd Edition, Volume 2, 304-3
On page 05, 6-cylinder and 8-cylinder in-line engines are described. The ignition angles of the cylinders are not constant, and the angle difference between the ignition angles of continuously ignited cylinders is "360 °.
It is said that two separate values which are symmetrical with respect to the average value of "/ (number of cylinders)" can be taken alternately. For a 6-cylinder engine, the two angle differences are 30 ° and 90 °
And for an 8-cylinder engine the difference between the two angles is 3
6.8 ° and 53.2 °. The combination of symmetric positions with respect to the average value and the even number of cylinders maintains the balance of the first and second inertial forces. Due to the non-constant ignition angle, the first class free moment is large and the second class free moment is small for the 6-cylinder engine, and the first class moment is smaller for the 8-cylinder engine.

Japanese Patent Application No. 56-136811
-37342), the non-constant ignition angle 0 °,
Disclosed is an engine with six cylinders ignited at 263 °, 134 °, 177 °, 53 °, 313 ° and having approximately equal reciprocating masses. These ignition angles can reduce the second-class vertical free moment, but the first-class moment becomes large and must be balanced by the counterweight. Also, the first
Since the degree of imbalance between the second-class force and the second-class force is large, the vibration level increases.

Japanese Patent Application No. 4-173884 (Japanese Patent Application Laid-Open No. 5-3
No. 40264) discloses a 4-cylinder V engine in which the angle between the cylinder rows is θ and the angle between the crank throws of the two cylinder rows is (π−2θ). And in one direction,
All crank throws form an angle θ with the horizontal. The mass of the pair of diametrically opposed cylinders is different from the mass of the other pair of diametrically opposed cylinders to reduce the first-class moment. The selected geometry for such ignition angle ensures that the inertial forces are always balanced, and that the adjustment of the mass of diametrically opposed paired cylinders affects the inertial forces. Without guaranteeing that it only affects the moment of inertia.

EP-A-0501096 discloses a 5-cylinder in-line engine in which the ignition angle of two symmetrically located cylinders is adjusted to provide a first-class engine. The moment of inertia is reduced, but in this case the adjustment is made to maintain symmetry to maintain the balance of inertial forces of the first class.

[0009]

OBJECTS OF THE INVENTION The object of the present invention is to provide a first engine
It is to provide a method for optimizing the ignition angle in order to be able to substantially reduce one or more selected vibration parameters while maintaining the balance of inertial forces of the first and second classes.

[0010]

To achieve the above object, the method according to the invention is characterized in that the first and second grades are arranged in such a way as to reduce at least one selected vibration parameter of the engine. The first ignition angle is optimized by making the inertial force of the class irrelevant to unbalance the inertial force of the first class, and the inertial force of the second class is also unbalanced when the reciprocating mass of the cylinder is the same. Equilibrating; then adjusting the reciprocating masses of at least two cylinders to be different from the reciprocating masses of the remaining cylinders, and
It is to balance the inertial force of the class (preferably also the inertial force of the second class).

By making the primary and secondary inertial forces irrelevant at the optimum ignition angle, the ignition angle can be selected with substantially greater degrees of freedom,
Better selected parameters can be reduced compared to conventional engines where these inertial forces had to be taken into account in determining the ignition angle. According to the present invention, a first or second class free moment, a selected class H or X model guide force moment, or a selected class of axial shaft vibration and / or torsion shaft vibration. At least one of the selected vibration parameters as described above is minimized to a harmless level by optimizing the ignition angle, and a compensator or the like which has been conventionally required can be omitted. When the ignition angle is determined by such a method and the shape of the crankshaft is determined based on the ignition angle, the present invention adjusts the reciprocating mass of the cylinder so that the inertial forces of the first class and the second class are balanced. .

The invention also comprises several cylinders, each having a piston connected to an associated crank throw on a common crank shaft, the crank throw being positioned at a predetermined angular position corresponding to the ignition angle of the cylinder. And at least two of the angular differences between the ignition angles of the cylinders that are successively ignited have different dimensions, each cylinder including at least the mass of the piston and the mass of a portion of the connecting rod A two-stroke inline engine, such as a marine main engine, having a reciprocating engine component having a reciprocating mass. According to the invention, a feature of this engine is that the ignition angle (α) is optimized to reduce selected vibration parameters,

[Equation 5] as well as

[Equation 6] The reciprocating mass of the cylinder is adjusted,

[Equation 7] as well as

[Equation 8] Is to be satisfied.

In these equations, the cylinder number is n, the number of cylinders of the engine is N, the ignition angle of the _nth cylinder is α _n , and the reciprocating mass of the nth cylinder is M _r , _Denote by _n . By making the first-order inertial forces independent, the selected vibration parameters can be substantially reduced compared to conventional engines, while at the same time the selected optimum ignition angle is Crankshaft geometry such that the result of the addition of the geometrical primary and secondary forces shown in equations 1 and 2 differs from zero (significantly deviates from zero) Provide the shape. This means that at least the first-order free (external) inertial forces are unbalanced for the same cylinder mass. As can be seen from the above equations 3 and 4,
When considering the reciprocating mass of the cylinder M _r , _n , substantially the above equilibrium is obtained, which means that a first-order free inertial force (and preferably a second-order free inertial force) is applied to the engine. It means that it is virtually nonexistent. The reason is that the mass of the cylinder is adjusted in such a way as to compensate for the consequences of not considering inertial forces in determining the ignition angle.

The feature of the embodiment of the engine having six cylinders is that the ignition angles of the first to sixth cylinders are 356-4 °, 233-241 °, and 1
06-114 °, 143-151 °, 266-274 °
And a firing interval of 16-24 ° or symmetrical 356
-4 °, 246-254 °, 123-131 °, 86-
94 °, 213-221 ° and 336-344 ° ignition intervals, respectively; the reciprocating masses of at least two cylinders and the reciprocating masses of the remaining cylinders are different, so that It is to substantially balance the inertial force. Crankshaft rotation axis 0-180 °
With respect to, the latter ignition interval is mirror-symmetric with respect to the former ignition interval.

The ignition angle can significantly reduce the first-class external moment, and at the same time, substantially reduce the second-class external moment, whereby the conventionally used second-class moment is used. You don't have to use a compensator. Further, the above ignition angle favorably distributes the H type guide force moment with respect to the frequency with respect to the crosshead engine, so that the lateral upper column of the 6 cylinder engine which has been used conventionally is not used. I'm done.

For a set of selected ignition angles, the first
Balances of inertial forces of the class 1 and 2 can be obtained with several different mass distributions. As is well known, inertial force is
For the class power, the vector of each cylinder was plotted at the angular position corresponding to the ignition angle of the cylinder, and for the second class force, the vector of each cylinder was plotted at the angular position corresponding to twice the ignition angle of the cylinder. It can be represented by a vector in a vector diagram. In the case of balancing, the vectors may be added to obtain a zero vector. If all vectors have the same vector length corresponding to all cylinders with the same mass, then more than one until a balance for the first-order force (and preferably the second-order force) is obtained. Adjust the vector length of. For a 6-cylinder engine with 6 vectors pointing in 6 different directions, it is clear that different combinations of vector lengths corresponding to different distributions of cylinder mass can achieve equilibrium.
The vector length is directly proportional to the reciprocating mass of the cylinder.

In the preferred embodiment, the ignition angles of the first through sixth cylinders are 0 ° and 23, respectively.
7 °, 110 °, 147 °, 270 ° and 20 °;
The reciprocating masses of the 2nd, 4th and 6th cylinders are 1 from the reciprocating masses of the remaining cylinders.
Weight up by 2%, 16% and 1%. With such an ignition angle, the first-class moment is reduced by 90% with respect to the known level, the second-class moment is reduced by 50% with respect to the known level, and further, in the single-pull torsion mode. Shaft vibration is induced by the third class forces and moments of the engine, and not by the sixth class forces and moments. This means that the speed range of a 6-cylinder engine with an optimal ignition angle is not constrained, and continuous operation of the engine is possible.

The feature of the embodiment for a 10-cylinder engine is that the ignition angles of the first to tenth cylinders are 358-2 °, 252-256 °, 114.
-118 °, 227-231 °, 140-144 °, 3
42-346 °, 80-84 °, 34-38 °, 183
-187 ° and 287-291 ° firing intervals or symmetrical 358-2 °, 254-258 °, 105-1
09 °, 151-155 °, 53-57 °, 211-2
15 °, 298-302 °, 185-189 °, 323
-327 [deg.] And 69-73 [deg.] Firing intervals respectively; the reciprocating mass of at least two cylinders and the reciprocating masses of the remaining cylinders are made different so that the primary and secondary inertial forces are substantially It is to equilibrate above.

First and second order, depending only on the geometry
0 °, 254 °, 114 to balance the inertial force of the class
°, 226 °, 139 °, 340 °, 81 ° 29 °, 1
Compared to a conventional 10-cylinder engine having an ignition angle of 81 ° and 280 °, the ignition angle of the present invention can substantially reduce the crankshaft torsional vibration, and the torsion required in a conventional engine. The vibration damper can be omitted.

In the preferred embodiment for extremely low levels of vibration, the ignition angles (α) of the first through tenth cylinders are 0 °, 254 ° and 116, respectively.
°, 229 °, 142 °, 344 °, 82 °, 36 °,
185 ° and 289 °; second, fourth, fifth
The reciprocating masses of the third, sixth, ninth and tenth cylinders are 3.0%, 3.1%, 2.8%, 0.7% respectively from the reciprocating masses of the remaining cylinders. 5.
Weight up by 0% and 4.0%. Further, the ignition angles of the 1st to 10th cylinders are 0 ° and 25 °, respectively.
6 °, 107 °, 153 °, 55 °, 213 °, 300
°, 187 °, 325 ° and 71 °; the reciprocating masses of the first, second, fifth, sixth, seventh and ninth cylinders and the reciprocating masses of the remaining cylinders. 4.0%, 5.0%, 0.7%, 2.
Similar effects can be obtained when the weights are increased by 8%, 3.1% and 3.0%.

By providing an extra reciprocating mass on the piston or at the upper end of the connecting rod, a different reciprocating mass can be provided for the heavier cylinder. For example, for a piston, the mass can be located inside the skirt of the piston.

In the crosshead engine, the mass can be changed by another method. For example, forming a bore in the crosshead pin of the lighter cylinder or providing extra mass in association with the crosshead structure of the heavier cylinder may provide a difference in the reciprocating mass of the cylinder. it can. By providing a bore in the crosshead pin and / or piston rod,
This is advantageous because the reciprocating mass of the cylinder itself is small.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENT The large two-stroke crosshead engine 1 shown in FIG. 1 comprises a base plate 2 on which the frame box 3 and cylinder section 4 of the engine are mounted. In the frame box, a vertical guide surface 6 for the crosshead 6 is fixed and laterally guides the crosshead. The piston 7 is mounted in a cylinder liner 8 and is connected to the crosshead via a piston rod 9, the crosshead pin being rotatably mounted on an associated connecting rod pin 11 on the crank throw of the crankshaft 12. It is attached to 10.

The center-to-center distance (crankshaft radius) between the main bearing journal of the crankshaft and the connecting rod pin is indicated by the symbol R, and the length of the connecting rod is indicated by the symbol L. The crosshead is separated from the main bearing journal by a vertical distance S. The distance S changes sequentially during the reciprocating movement of the piston in the vertical direction, and the acceleration of the piston can be determined as the ^second derivative d ² S / dt ² of the distance S, as described in the article by Taylor.

This acceleration acts on the reciprocating mass Mr to generate an inertial force Fp, which causes an opposite reaction force -Fp on the bed plate via the connecting rod and the crank throw. The horizontal force Fg acts on the guide surface due to the transmission of the force via the connecting rod positioned at an angle.

The reciprocating mass Mr of the cylinder comprises the mass of the piston with the associated piston ring, etc., the mass of the piston rod, the mass of the crosshead structure and the mass of part of the connecting rod. In addition, the cylinder has a rotating mass that includes the mass of the remaining part of the connecting rod, the mass of the crank throw and the mass of the parts of the two associated main bearing journals.

The engine can be used as a propulsion engine for ships, in which case the engine is connected to the propeller via a shaft device driven by the crankshaft 12 and subject to axial and torsional vibrations from the engine. To be done. Alternatively, the engine can be used as a stationary generator engine, in which case the crankshaft is connected to the generator. Engine power can vary from 2000 kW up to a nominal maximum power of 70000 Kw or higher.

In a typical engine, the inner diameter of the cylinder bore is 60 cm, and in the 6-cylinder model the engine power is about 12250 kW. For example, in this engine, the rotational mass Mr for a cylinder that does not include excess mass is 5560 kg, the radius R of the crankshaft is 1.15 m, the length L of the connecting rod is 2.63 m, and the distance between the cylinders is The distance d is 1.01 m. The crankshaft radius, connecting rod length and inter-cylinder distance are the same for all cylinders.

Tables 1 and 2 described later show typical ignition angles and the like for the conventional engine and the engines according to the embodiments of the present invention as the 6-cylinder engine and the 10-cylinder engine.

[0030]

[Table 1] Table 1 Conventional constant-interval ignition cylinder number n 1 2 3 4 5 6 Ignition angle α 0 240 120 120 180 60 300 Ignition sequence j 1 5 3 4 2 6 Angle difference α _j -α _j-1 60 60 60 60 60 60 Conventional non-uniform ignition interval Cylinder number n 1 2 3 4 5 6 Ignition angle α 0 240 120 120 150 270 30 Ignition sequence j 1 5 3 4 6 2 Angular difference α _j -α _j-1 90 90 90 30 30 30 30 Related to the present invention Cylinder number n 1 2 3 4 5 6 Ignition angle α 0 237 110 147 270 20 Ignition sequence j 1 5 3 4 6 2 Angle difference α _j -α _j-1 90 90 90 37 37 43 20 Relative mass Mr 1 1.12 1 1.16 1 1.01 Symmetrical structure Cylinder number n 1 2 3 4 5 6 Ignition angle α 0 250 127 127 90 217 340 Ignition order j 1 5 3 2 4 6 Angle difference α _j -α _j-1 20 43 37 90 90 90 90 Relative mass Mr 1.01 1 1.16 1 1.12 1

[Table 2] Table 2 Conventional non-uniform ignition interval Cylinder number n 1 2 3 4 5 Ignition angle α 0 254 114 226 139 Ignition sequence j 1 8 4 7 5 Angle difference α _j -α _j-1 20 28 33 33 45 25 Relative Mass Mr 1 1 1 1 1 Conventional Non-uniform Ignition Interval Cylinder No. n 6 7 8 9 10 Ignition Angle α 340 81 29 181 280 Ignition Sequence j 10 3 2 6 9 Angular Difference α _j -α _j-1 60 52 29 42 26 Relative mass Mr 1 1 1 1 1 1 According to the invention Cylinder number n 1 2 3 4 5 Ignition angle α 0 254 116 229 142 Ignition sequence j 1 8 4 7 5 Angular difference α _j -α _j-1 16 25 34 44 26 Relative mass Mr 1 1.03 1 1.031 1 According to the present invention Cylinder number n 6 7 8 9 10 Ignition angle α 344 82 36 185 289 Ignition sequence j 10 3 2 6 9 Angle difference α _j -α _j-1 55 6 36 43 35 relative mass Mr 1.028 1 1 1.05 1.04 symmetrical structure cylinder number n 1 2 3 4 5 ignition angle α 0 256 107 153 55 firing order j 1 8 4 5 2 angular difference alpha _j over alpha _j-1 35 43 36 46 55 Relative mass Mr 1.04 1.05 1 1 1.028 Symmetrical structure Cylinder number n 6 7 8 9 10 Ignition angle α 213 300 187 325 71 Ignition sequence j 7 9 6 10 3 Angle difference α _j -α _j-1 26 44 34 25 16 Relative mass Mr 1 1.031 1 1.03 1

In the embodiment according to the present invention, the reciprocating masses Mr of the respective cylinders are not equal, but they are adjusted so as to balance the inertial forces of the first and second classes with respect to the engine as a whole. This will be described later in detail with reference to FIGS.

The extra mass for a heavier cylinder is
On or to the crosshead, for example, by attaching half the mass to each of the two crosshead shoes of the crosshead, or by using an appropriately weighted associated crosshead shoe. Can be set related. In addition, the extra mass may be provided on the bottom side of the bearing housing of the crosshead, or may be set in relation to the upper flange of the connecting rod attached to the bearing housing. Of course, the attachment of a separate mass to the desired engine element has the advantage that the engine element can be manufactured in the usual way using common elements for all cylinders. Another approach is to use split bearings of various sizes to clamp it to the top of the connecting rod, or to use an annular segment mass to mount it inside the skirt of the piston. If you do this,
Especially effective for trunk engines.

At least a portion of the mass difference is obtained by reducing the mass of the lightweight cylinder for relative mass 1 shown in the table above. Mass can be reduced by providing the crosshead pin with a bore, particularly a longitudinal central bore.

Another method is to reduce the mass of the piston rod by increasing the diameter of the central longitudinal bore of the piston rod. This bore is provided to supply and remove cooling oil to the piston,
Cooling oil is supplied into the piston through a through pipe coaxially inserted in this bore and returns through an annular space around the pipe. The piston cooling is not affected even if the drain side flow rate increases. Even if the piston rod length is increased, the substantial mass difference can be caused by changing the diameter of the central bore or, if keeping the bore diameter the same, the wall thickness of the pipe inserted into the bore. Can be obtained by changing.

Calculation of external or free forces and moments, H and X type guide force moments, and torsional vibrations in shaft systems is well known to those skilled in the art,
For example, in the chapter “Engine Balance and Vibration” (Vol. 2, pages 240-305) of the document by Taylor mentioned above, 199 by the present applicant.
The document "Introduction to the vibrational morphology of two-stroke diesel engines in ships" from September 2000 (An Introducti
on to Vibration Aspects of Two-stroke DieselEngine
in Ships) and the article "Vibration characteristics of a two-stroke low-speed diesel engine" from January 1993 (Vibration C
haracteriztics of Two-stroke Low SpeedDiesel Engin
es).

FIG. 2 shows "according to the present invention" in Table 1.
6 shows the angular position of the crank throw 13 of a 6-cylinder engine. Cylinder numbers C ₁ -C ₆ are displayed adjacent to the crank throw, and the number designations are C ₁ , ..., C _{6 in} order from the driven shaft. Cylinder liner 8
The longitudinal axis 14 of the crankshaft intersects the longitudinal axis 15 of the crankshaft at a right angle, and all of them lie in the same central plane located midway between the guide surfaces 5. As shown, the longitudinal axes of the cylinders are equally spaced in the longitudinal direction of the engine, d _{ii + 1} , but of course there is room for chain wheels between the cylinders in an engine having, for example, 12 cylinders. Therefore, it is also possible for at least one of these intervals to be larger than the other intervals.

The free force or free moment from the engine is transmitted to the surrounding structure (eg, ship body) via the engine installation seat and vibrates the structure. In particular, the first-class inertial force is large (and the second-class inertial force is also large), so it is necessary to avoid undesired vibrations in which the inertial forces from the individual cylinders balance so as to produce only free moments. is there.

The free force of the first class is a vector diagram as shown in FIG. 3. The vector for each cylinder extends in an angle corresponding to the ignition angle of the cylinder and has a length proportional to the reciprocating mass of the cylinder. It can be determined by plotting. The inertial force from each cylinder is 0-
Obtained by projecting the vector at a right angle onto 180 °. By adding the individual vectors, it is possible to obtain a first-class free force.

In a similar manner, a second-class free force can be obtained by plotting and adding the vectors of the vector diagram shown in FIG. 4, but in this case, the vector is the ignition angle 2 Must be plotted at an angle that corresponds to double. The ratio between the magnitude of the primary force and the magnitude of the secondary force of the cylinder is L / R, which in the above-mentioned typical engine corresponds to 44% of the primary force. A second-class inertial force is generated. By adding the vectors of FIGS. 3 and 4, at the ignition angle shown in Table 1,
It is possible to prevent generation of the first-class and second-class free inertial forces with respect to the embodiment according to the present invention. Correspondingly, the vector diagram can be plotted so as not to generate the first-class and second-class free inertial forces even in the embodiment for the 10-cylinder engine.

The first and second inertial forces generate first and second moments. In the calculation of the moment, its starting point is chosen so that the moment from the inertial forces of the individual cylinders can be determined in the usual way.
The free moment is determined by adding the moments from each cylinder.

Table 1 shows that conventional constant-interval ignition results in automatically balancing first and second class vectors for the same vector length. This is referred to as the first type of ignition angle.

Further, as shown in Table 1, the angular difference (α _j -α _j-1 ) between the cylinders which are continuously ignited is two values (30 ° and 30 °) which are symmetrical with respect to the average ignition angle (60 °). 90
There is also a conventional engine with a non-uniform ignition angle, such as having a (°) (which means that the paired vector corresponds to the vector in an engine with a constant ignition angle). In engines with these conventional non-uniform ignition angles, automatic balancing is obtained for the same vector length. This is referred to as the second type of ignition angle, where the engine has the same reciprocating mass and the first
Has a non-uniform ignition angle selected to balance the primary and secondary forces. The balance of the primary and secondary inertial forces in an engine having a first or second type of ignition angle depends on the geometrical characteristics of the selected ignition angle, i.e. can get.

[0043]

[Equation 9] This severely limits the possibility of reducing the selected vibration parameter by optimizing the ignition angle and therefore is provided on the crankshaft associated with the above-mentioned conventional 10-cylinder engine with non-uniform ignition spacing. It was necessary to use an external vibration compensator such as a torsion dampener.

The present invention provides an engine having a third type of ignition angle (ie, an ignition angle that is irregular but can be optimized without restraint, for example, to reduce guide force moments or vibration modes of the shaft). 1st and 2nd
The balance of inertial force of the class is obtained by changing the vector length, that is, the reciprocating mass Mr of the cylinder. In the 10-cylinder engine shown in Table 2, the critical torsional vibration of the shaft generated by the engine is reduced to the extent that the speed range of the engine is not restricted, and it is not necessary to provide a torsional vibration damper on the shaft as in the conventional case.

Although the embodiments of the present invention have been described in detail with respect to the crosshead engine, it goes without saying that the present invention can be applied to a trunk engine.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a cylinder of a two-stroke crosshead engine.

FIG. 2 is a perspective view showing one angle of a crank throw in a crank shaft of an engine.

FIG. 3 is a vector diagram relating to a first-class inertial force.

FIG. 4 is a vector diagram relating to a second-class inertial force.

[Explanation of symbols]

 1 In-line engine 4 Cylinder section 6 Crosshead 7 Piston 9 Piston rod 10 Connecting rod 12 Crankshaft 14 Crank throw α Ignition angle

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location F02D 45/00 330 F02P 5/15

Claims (11)

[Claims] 1. A plurality of cylinders (Ci) each comprising a piston (7) connected to an associated crankthrow (14) on a common crankshaft (12), said crankthrow of said cylinders. The cylinder is positioned at a predetermined angular position corresponding to the ignition angle, and the angle difference (α _j −
at least two of α _j-1 ) have different dimensions,
An inline engine, such as a marine main engine, in which each cylinder comprises a reciprocating engine component having an associated reciprocating mass (Mr) including at least the mass of the piston and the mass of a portion of the connecting rod. A method for optimizing an ignition angle (α) in (1) by making the first and second inertia forces unrelated in a manner that reduces at least one selected vibration parameter of the engine. 1 Ignition angle (α) is optimized to unbalance the inertial force of the first class and also unbalance the inertial force of the second class when the reciprocating mass (Mr) of the cylinder is the same; Adjusting the reciprocating mass (Mr) of at least two cylinders different from the reciprocating mass (Mr) of the remaining cylinders, Wherein the balancing the primary inertial force of. 2. A plurality of cylinders (C) each having a piston connected to an associated crank throw (14) on a common crank shaft (12), said crank throw being at an ignition angle of said cylinder. The angular difference (α _j −α) between the ignition angles (α) of the cylinders that are positioned at the corresponding predetermined angular positions and that are continuously ignited.
_j-1 ) at least two of which have different dimensions, each cylinder having an associated reciprocating mass (Mr) including at least the mass of the piston and the mass of a portion of the connecting rod (10). In an in-line engine (1), such as a ship's main engine, including a kinetic engine component, the ignition angle (α) is optimized to reduce selected vibration parameters, And The reciprocating mass of the cylinder is adjusted, and And A two-stroke inline engine that satisfies the requirements of 3. The in-line engine according to claim 2, wherein in the two-stroke in-line engine having six cylinders (C), the ignition angles of the first to sixth cylinders are 3.
56-4 °, 233-241 °, 106-114 °, 1
43-151 °, 266-274 ° and 16-24 ° firing intervals or symmetrical 356-4 °, 246-2
54 °, 123-131 °, 86-94 °, 213-2
21.degree. And 336-344.degree., Respectively; the reciprocating mass of at least two cylinders and the reciprocating masses of the remaining cylinders are different so that the primary and secondary inertial forces are substantially An in-line engine characterized by upper balance. 4. The ignition angles of the first to sixth cylinders are 0 °, 237 °, 110 °, respectively.
147 °, 270 ° and 20 °; second, fourth
The two-stroke inline engine of claim 3, wherein the reciprocating masses of the thirteenth and sixth cylinders are 12%, 16% and 1% heavier than the reciprocating masses of the remaining cylinders, respectively. 5. The ignition angles of the first to sixth cylinders are 0 °, 250 ° and 127 °, respectively.
90 °, 217 ° and 340 °; first, third
The two-stroke inline engine of claim 3, wherein the reciprocating masses of the third and fifth cylinders are 1%, 16% and 12% heavier than the reciprocating masses of the remaining cylinders, respectively. 6. The in-line engine according to claim 2, wherein in the two-stroke in-line engine having 10 cylinders (C), the ignition angles of the first to tenth cylinders are 358-2 ° and 252. -256 °, 114-118 °,
227-231 °, 140-144 °, 342-346
Ignition intervals of 35 °, 80-84 °, 34-38 °, 183-187 ° and 287-291 ° or 35 symmetrical thereto.
8-2 °, 254-258 °, 105-109 °, 15
1-155 °, 53-57 °, 211-215 °, 29
8-302 °, 185-189 °, 323-327 ° and 69-73 °, respectively, with different reciprocating masses of at least two of the cylinders and the remaining cylinders, A two-stroke in-line engine characterized by substantially balancing the inertial forces of the first and second classes. 7. The ignition angles of the first to tenth cylinders are 0 °, 254 ° and 116, respectively.
°, 229 °, 142 °, 344 °, 82 °, 36 °,
185 ° and 289 °; the reciprocating masses of the 2nd, 4th, 5th, 6th, 9th and 10th cylinders are respectively 3. 0%, 3.1%, 2.8%, 0.7%,
The two-stroke inline engine of claim 6, wherein the two-stroke inline engine is heavier by 5.0% and 4.0%. 8. The ignition angles of the first to tenth cylinders are 0 °, 256 ° and 107, respectively.
°, 153 °, 55 °, 213 °, 300 °, 187
°, 325 ° and 71 °; first, second,
The reciprocating masses of the 5th, 6th, 7th and 9th cylinders are 4.0%, 5.0%, 0.7% and 2.8 respectively from the reciprocating masses of the remaining cylinders. %,
7. The two-stroke inline engine of claim 6 which is 3.1% and 3.0% heavier. 9. An extra reciprocating mass of the heavier cylinder is provided on the piston (7) and at the upper end of the connecting rod (10). 2-stroke inline engine. 10. The engine (1) is a crosshead engine, wherein the extra mass is associated with the formation of a bore in the crosshead pin of the lighter cylinder or the crosshead structure (6) of the heavier cylinder. The two-stroke in-line engine according to any one of claims 2 to 9, wherein a difference in the reciprocating mass of the cylinder is provided by providing or not. 11. The engine is a (1) crosshead engine, wherein the mass of the piston rod (9) is employed to provide a difference in the reciprocating mass of the cylinder. The 2-stroke inline engine according to any one of 10.