CN1107204A

CN1107204A - Internal combustion engine

Info

Publication number: CN1107204A
Application number: CN93120555A
Authority: CN
Inventors: H·林奎斯特
Original assignee: MAN B&W Diesel AS
Current assignee: MAN B&W Diesel GmbH; MAN B&W Diesel AS
Priority date: 1993-06-04
Filing date: 1993-11-27
Publication date: 1995-08-23
Anticipated expiration: 2013-11-27
Also published as: JPH08510027A; CN1044732C; KR100291805B1; JP3217369B2; DK9300283U4; KR950702672A; WO1994029580A1

Abstract

An internal combustion engine, in particular a large two-stroke crosshead engine for propelling a ship, has a number of cylinders each of which has a piston connected with an associated throw (2, 3) in a crankshaft (1) common to the cylinders, the throw being so connected through main journals journalled in main bearings that adjacent throws have a predetermined mutual angularity and that said angularity is varying for at least some of the neighbouring throws. A control device doses a larger amount of oil to cylinders (Cn) whose throw (2, 3) forms a large angle ( alpha ) with the adjacent throws than is dosed to the cylinders whose throw forms the smallest angle with a neighbouring throw. In an eight-cylinder engine the control device may dose most oil to cylinders Nos. 1, 2, 7 and 8. In a twelve-cylinder engine the control device may dose least oil to cylinders Nos. 9 and 10.

Description

Internal combustion engine

The present invention relates to internal-combustion engine, relate in particular to the large-scale two-stroke crosshead internal-combustion engine that promotes boats and ships, it has many cylinders, and each cylinder has a piston, and piston links to each other with the associated crank of the shared bent axle of these cylinders, the main journal of crank in being supported on main bearing connects like this, make crank have predetermined mutual angle, described angle changes for some adjacent crank at least, wherein, the amount of fuel that sprays into cylinder in engine operational cycle is adjustable by control gear.

Japanese patent application publication No.62-113844 has narrated a kind of control gear that is passed to the indoor fuel quantity of diesel combustion during the engine operation through petrolift that is used to be adjusted in.The Japanese Patent Publication invention disclosed with a kind of like this motor as starting point, wherein the cam that is fixed on the protruding axle of the fuel initial timing of spraying is controlled, and fuel injection amount is in the control that the punctual valve opening time of fuel pump conveyor side changes according to engine load.Should have been sprayed full engine load running operating mode optimization by the initial fuel of cam, the injection timing when this causes sub load running operating mode is too late with respect to engine operational cycle, and only limited fuel quantity can be sprayed.Therefore, when sub load, motor does not produce each parts of motor is applied full-power power.This Japan's publication suggestion adopts computer to control the zero-time that fuel sprays as control gear, like this, under sub load running operating mode, early constantly can spray the engine power of an extra fuel quantity when increasing sub load in engine operational cycle.This computer receives engine speed and from the signal that is configured in the thermosensor in the main bearing, can not increase the overload that causes because of engine power when the sub load to guarantee this bearing.

Usually wish that all main bearings of motor are identical, like this, needn't purchase and store several different main bearing spare parts, and in motor, can not load onto the main bearing of wrong number.

The objective of the invention is to improve the power of motor when full load and sub load, carry lotus and be no more than the maximum principal axis of being allowed.

Thus, internal-combustion engine of the present invention has such characteristics, and described control gear follows adjacent crank to constitute the amount of fuel of those cylinders of minimum angles with the amount of fuel that adjacent crank constitutes those cylinders distribution of wide-angle more than the crank of distributing to the place cylinder to the crank of place cylinder.

At the main bearing that constitutes between the crank of seeing minimum angles along the bent axle circumferencial direction, bear king-sized load, part is owing to cause produce with joint efforts at two outside adjacent cranks of bent axle the same side radial finger, part is owing to be installed in the compressive force that two connecting rods on the rod journal of two adjacent cranks produce and cause, because the combustion process in the pairwise correlation cylinder-having in the motor of some cylinders-only be the phase place of crossing by corresponding to a certain angular misalignment of angle between this two adjacent crank.Therefore, this main bearing must be accepted the compression load of two cylinders simultaneously.As mentioned above, it has been generally acknowledged that all main bearings are that same structure is suitable, this means that in this known motor, thereby the heaviest bearing of load is in the upper limit of all cylinder mean pressure power.Distribute a large amount of fuel oils by the crank to the place cylinder with the cylinder that adjacent crank constitutes mitre, the overload capacity of the main bearing between these cranks has obtained utilization, gives motor bigger power.This extra power can obtain under all loads of motor.Like this, in motor of the present invention, the more known motor of these main bearings has more uniform load.

In the preferential embodiment of one 8 cylinder engine, control gear distributes maximum fuel oils to 1,2,7 and 8 cylinders.In 8 cylinder engines, the corresponding angle between the crank of the angle between the crank of 3,4 cylinders and 5,6 cylinders is 45 °, and the angle between the crank of remaining cylinders is 135 ° or 225 °.Here the angle of being mentioned is equivalent to the phase shifts between the above-mentioned cylinder compression stroke starting point.Because there is big difference in described corner dimension, cylinder 1,2,7 and 8 can increase a lot of power, and can not make the main bearing overburdening between cylinder 1-2,2-3,6-7 and the 7-8.

In another preferential embodiment of 12 cylinder engines, control gear distributes minimum fuel oil to cylinder 9 and 10.To 12 cylinder engines, the phase difference between angle between the adjacent crank and the adjacent cylinder compression stroke starting point is 120 °, and 210 ° or 300 °, just the described angle between the cylinder 9 and 10 only is 30 °.Because there is big difference in the described angle between the cylinder 9 and 10 with the described angle between the motor remaining cylinders,, can makes and start function to be significantly improved and can not make the bearing overburdening with regard to 12 cylinder engines.

Best, the such dispense fuel amount of this control gear when all bearings are identical, makes between the crank main bearing basic uniformity of loading, and this load capacity with respect to main bearing is given motor with the highest performance." main bearing between the crank " is considered to mean the main bearing that is in the crank two ends and need not be comprised in the optimization, because they are influenced by the load of a cylinder only.If two main bearings of configuration between two cranks, because this crank is made up of the two axle parts that separate, same consideration is applicable to also bears only these two bearings that cylinder is loaded basically.

With reference to these very simple accompanying drawings, will narrate embodiments of the invention in more detail below, wherein:

Fig. 1 is the perspective principle sketch of 8 Cylinder engine bent axles;

Fig. 2 and Fig. 3 are respectively angle and ignition order figure between the crank of 8 cylinders and twelve-cylinder engine.

The present invention is useful especially for the large-sized two-stroke+prefix motor that advances boats and ships or as the stationary power generation motor, because these motors every cylinder when the slow-speed of revolution produces great power, this makes main bearing bear heavy load.For motor length is dwindled, wish that the length of main bearing is not too big, this has limited the area of these main bearings.

The ignition order of these cylinders is that the moving situation of knob rotational oscillation determines, and wishes to limit these may come across independently quality moment of the first order in engine bearer and the hull and the second level when starting to turn round.Angle between the crank of two sequentially fired cylinders, in two stroke engine should be 360 ° of quilts divided by cylinder number, for four-stroke start power, then be that 720 ° of quilts are divided by cylinder number.For two-stroke 8 Cylinder engines, this angle is 45 °, and in the two-stroke twelve-cylinder engine, then is 30 °.

Fig. 1 represents totally by the song of 8 cylinder two-stroke motors of label 1 mark.This main journal is supported among the main bearing MB1-MB9, and wherein MB1 and MB9 are in this two ends, and MB _5aAnd MB _5bBe in this middle part, in the joint both sides of the bent axle of making by diaxon spare.If the fuel pump of motor and air valve are subjected to camshaft control, then a sprocket wheel that drives this camshaft through chain drive mechanism can be installed in this joint.For cylinder C ₁-C ₈In each cylinder, bent axle 1 has by two crankwebs 2 that are connected in the pairwise correlation main journal and the crank be made up of the connecting rod pivot pin 3 of this two arms supporting, and the connecting rod (not shown) is housed on the connecting rod pivot pin.This connecting rod is connected in piston in the associated cylinder through crosshead and piston rod.

The typical ignition order of 8 Cylinder engines is represented in the following Table 1.

During cylinder that first hurdle of this table is represented to be correlated with, the angle α between the two right adjacent cranks of cylinder in first hurdle is represented to belong in second hurdle.Shown in α corresponding to the phase shifts between the right combustion stroke starting point of associated cylinder, therefore, can directly find out from the expression of angle, be in cylinder between main bearing whether can be subjected to the effect of the compressive force of two cylinders simultaneously.The third column of this table is illustrated in the ignition order of first cylinder of this cylinder centering.

Table 1

8 cylinders

Cylinder is to angle α ° ignition order

15 1-2 225 1

2-3 225 6

3-4 45 3

4-5 135 4

5-6 45 7

20 6-7 225 8

7-8 135 5

8-1 (135) 2

The content schematic drawing of table 1 is shown among Fig. 2, wherein, is expressed as complete alternation by a complete engine operational cycle of 360 ° of axle rotations.Because this motor is 8 Cylinder engines, this circulation is divided into 45 ° of intervals, and the bent axle that is equivalent between the two order piston combustion stroke starting points rotates.In each rotation at interval, pointed out to carry out the number n of the cylinder Cn of combustion stroke.Angle between the two adjacent cranks can directly read to be the angle between the two radius that belongs to this two cylinder from this figure.Between cylinder 1 and 2, can see this angle α 1-2=225 °, for other cylinder, the rest may be inferred.Between cylinder 5 and 6, can see this angle α 5-6=45 °, can see that also cylinder 6 lights immediately behind cylinder 5, this means between this two cylinder main bearing must accept the compressive force of two connecting rods simultaneously.Corresponding situation is suitable for cylinder 3 and 4.Therefore, control gear can distribute maximum amount of fuel to cylinder 1 and 2.And cylinder 3-6 is distributed minimum amount of fuel, cylinder 7 and 8 amount of fuel of distributing then are between other two amounts.

Illustrate the situation of twelve-cylinder engine at Fig. 3, and represent in the following Table 2.

Table 2

Cylinder

Cylinder is to angle α ° ignition order

1-2 120 1

2-3 120 5

3-4 210 9

20 4-5 120 4

5-6 120 8

6-7 300 12

7-8 120 10

8-9 120 2

25 9-10 30 6

10-11 120 7

11-12 120 11

12-1 (300) 3

Can see that control gear can distribute maximum amount of fuel to cylinder 6,7 and 12, and cylinder 3 and 4 is distributed less amount of fuel, and cylinder 1,2,4,5,7,8 and 11 is distributed medium amount of fuel, and cylinder 9 and 10 is distributed minimum amount of fuel.

If this motor is the traditional design motor with camshaft control fuel pump, this control gear can be a kind of scale bar of regulating the pump scale according to engine load.This pump can connect control scale bar this moment like this, it is aligned consistently, so that the amount of fuel that is provided with differing from one another when full engine load.

If this motor is computer-controlled modern motor, but this control gear can comprise computer and for example electro-mechanical control or hydraulically operated petrolift operating unit.According to the preset data of mutual ratio between each bearing load, this computer can promptly be made each cylinder amount of fuel and be divided other to distribute like this, makes crankshaft main bearing bear the load of uniformity as far as possible.

If in main bearing, find to have problem, raise such as the bearing temperature that causes owing to clamping stagnation between bearing and the relevant axle journal, this computer can be by the interim cylinder that distributes a spot of fuel oil to give this bearing of vicinity of the program of compiling and editing.The possibility of loading on the selected bearing of this temporary transient minimizing is particularly advantageous in motor of the present invention, because all main bearings of this motor have born full load when the possibility of raising engine power provided by the invention has been fully utilized.Bear in the known motor of full-power at one to two main bearing only, not too need so temporary transient minimizing bearing load.

Claims

1, a kind of internal-combustion engine, in particular for advancing the large-sized two-stroke engine with outside guide of boats and ships, have some cylinders (Cn), each cylinder has a piston, follow the associated crank (2 on the shared bent axle of these cylinders (1), 3) link to each other, the main journal of these cranks in being supported on main bearing (MBn) is to connect like this, make adjacent crank that one predetermined angle (α) be arranged, described angle changes for some adjacent crank at least, wherein, the amount of fuel that sprays into during engine operational cycle in the cylinder is adjustable by means of control gear, it is characterized in that the crank (2 of this control gear to the place cylinder, 3) constitute amount of fuel that the cylinder (Cn) of mitre (α) distributes greater than constituting the amount of fuel that the cylinder of minimum angle distributes with adjacent crank with adjacent crank to the crank of place cylinder.

2, by the described internal-combustion engine of claim 1, it is characterized in that this motor has 8 cylinders, it is characterized in that this control gear is maximum to cylinder 1,2,7 and 8 fuel oils that distribute.

3, by the described internal-combustion engine of claim 1, wherein this motor has 12 cylinders, it is characterized in that this control gear gets few to cylinder 9 and 10 fuel oils that distribute.

4, by each described internal-combustion engine in the claim 1 to 3, it is characterized in that the such dispense fuel amount of this control gear, the load that each main bearing (MBn) between the crank (2,3) is born is roughly even.

5,, it is characterized in that in main bearing (MBn), finding under the problematic situation that this control gear is temporary transient to distribute more a spot of fuel oil in the cylinder (Cn) adjacent to this bearing by each described internal-combustion engine in the aforesaid right requirement.