KR102453430B1 - internal combustion engine for ships - Google Patents

Abstract

The engine 1 includes a two-stroke main engine 10, an intake passage 20 for introducing air into the main engine 10, and an exhaust turbine supercharger 40 for supercharging air flowing through the intake passage 20 and , a biasing device 70 for adding to the supercharging by the exhaust turbine supercharger 40, a rotation speed sensor 14 for detecting the engine rotation speed of the main engine 10, and controllers (101, 102, 103) that actuate the biasing device (70) when the engine speed of the main engine (10) rises to within a predetermined range.

Description

internal combustion engine for ships

The technology disclosed herein relates to a marine internal combustion engine.

For example, as described in Patent Document 1, in an internal combustion engine for ships, it is widely known that an exhaust turbine supercharger is used. Specifically, the internal combustion engine described in Patent Document 1 includes a main engine (diesel engine) and a turbine that receives exhaust from the main engine, and has a compressor (impeller) that sends compressed air to the main engine It is configured with an exhaust turbine supercharger.

Here, the internal combustion engine described in Patent Document 1 further includes an air source for auxiliary supply of pressurized air to the compressor, and uses this pressurized air to add to the supercharging by the exhaust turbine supercharger (air assist) is configured to do so.

Further, Patent Document 1 discloses that when the steering wheel is moved in order to engage the clutch related to the diesel engine, the pressurized air is applied.

In addition, in Patent Document 2, as an example of a method for controlling the force to the exhaust turbine supercharger, when the excess air rate is determined to be less than 1, or when the differential coefficient with respect to the time of the engine speed is smaller than a predetermined value, An auxiliary supply of pressurized air to an exhaust turbine supercharger is disclosed.

Similarly, Patent Document 3 discloses, as another example of a method of controlling the force to the exhaust turbine turbocharger, auxiliary supply of pressurized air to the exhaust turbine turbocharger when the differential coefficient with respect to the time of the fuel injection amount is greater than a predetermined value. have.

The configurations disclosed in Patent Documents 1 to 3 are common in that only the execution conditions are different, and when a predetermined condition is satisfied, the load to the exhaust turbine supercharger is automatically started.

Patent Document 1: Japanese Patent No. 4250102 Patent Document 2: Japanese Patent No. 3464891 Patent Document 3: Japanese Patent No. 3464896

In recent years, in order to cope with the tightening of regulations of CO ₂ emission based on EEDI, with respect to the size (weight of goods) of a ship, an internal combustion engine with a lower output tends to be used than before.

However, when a low-output internal combustion engine is used, since its displacement is reduced, for example, even if it is attempted to accelerate rapidly, the turbocharger turbine does not rotate responsively, and the rotation speed of the main engine may not sufficiently follow.

Therefore, as described in Patent Documents 1 to 3, it is conceivable to apply the pressure to the supercharging by the exhaust turbine supercharger by auxiliary supply of the pressurized air, but the inventor(s) of the present application earnestly study As a result, it was found that there was room for improvement in protecting the propulsion shaft system composed of the propeller shaft and the intermediate shaft.

That is, in large internal combustion engines for ships, in order to protect the aforementioned propulsion shaft system from torsional vibration stress generated during resonance, it is common to set a barred speed range before and after the resonance rotation speed.

In this case, at the time of acceleration of the main engine, it is required that the rotation speed of the main engine passes through the continuous use prohibition range (hereinafter, this range is referred to as "barred range") as quickly as possible. In order to respond to this request, it is conceivable to use the above-mentioned bias. However, in the configuration described in Patent Documents 1 to 3, it is added at a timing independent of the bard range, and as a result, it passes through the bard range. There is a risk of being at a disadvantage.

The technology disclosed herein has been made in view of such a point, and an object thereof is to more reliably protect a propulsion shaft system in a marine internal combustion engine configured to add to the supercharging by an exhaust turbine supercharger.

The technology disclosed herein relates to a marine internal combustion engine. This marine internal combustion engine has a two-stroke main engine, an intake passage for introducing air into the main engine, an exhaust turbine supercharger configured to supercharge air flowing through the intake passage, and supplying air to the exhaust turbine turbocharger, A biasing device configured to add to the supercharging by the exhaust turbine supercharger, a sensor detecting the engine speed of the main engine, and a controller controlling the biasing device based on a detection result by the sensor, the controller comprising: , when the engine speed of the main engine increases to within a predetermined range during acceleration of the main engine, the biasing device is operated.

According to this configuration, the biasing device adds air to the supercharger by supplying air to the exhaust turbine supercharger. Thereby, the supercharger can be operated responsively at the time of the acceleration of a ship, and it can further follow the rotation speed of a main engine.

Here, in the above-mentioned internal combustion engine for ships, when the engine rotation speed rises to within a predetermined range, it is configured to perform the biasing by the biasing device. For example, by setting this predetermined range based on the bard range, it is possible to pass the bard range as quickly as possible. Thereby, the propulsion shaft system can be protected more reliably.

Moreover, the said biasing device may apply to the said exhaust turbine supercharger over a predetermined time when the engine rotation speed of the said main engine rises to within a predetermined range.

In addition, the said predetermined range may be prescribed|regulated so that the resonance rotation speed of the propulsion shaft system in the said main engine may be included. Here, it is preferable that a bard range is included in the predetermined range.

In addition, the internal combustion engine for ships includes an exhaust passage for introducing exhaust exhaust from the main engine, and the exhaust turbine supercharger includes a compressor configured in the intake passage, and a turbine configured in the exhaust passage, The apparatus may supply air to the said compressor so that it may add to the rotation drive of the said compressor.

Further, the marine internal combustion engine may include an EGR passage formed by connecting a downstream portion of the compressor in the intake passage and an upstream portion of the turbine in the exhaust passage.

In general, when a configuration including a so-called high-pressure EGR system is adopted, the flow rate of the exhaust gas reaching the turbine is reduced by the amount of the exhaust gas refluxed through the EGR passage. This is not suitable for securing the responsiveness of the exhaust turbine supercharger.

As mentioned above, the structure which adds to the supercharging by an exhaust turbine supercharger is especially effective in the internal combustion engine provided with such a high pressure EGR system.

In addition, the marine internal combustion engine includes an exhaust purification device configured at a downstream side of the turbine in the exhaust passage and activated at a predetermined temperature or higher, and in the exhaust passage, bypassing the turbine and the exhaust purification device A bypass passage leading to

In general, in order to warm-up the exhaust purification device as quickly as possible or to keep the exhaust purification device in an active state, the relatively high temperature exhaust that has bypassed the turbine is purified by circulating the exhaust through the bypass passage as described above. In some cases, it is introduced into the device (so-called extraction operation). However, as the turbine is bypassed through the bypass passage, the flow rate of exhaust gas reaching the turbine is reduced. This is not suitable for securing the responsiveness of the exhaust turbine supercharger.

As described above, the configuration in addition to the supercharging by the exhaust turbine supercharger is particularly effective in an internal combustion engine provided with such an exhaust purification device.

As explained above, according to the said internal combustion engine for ships, a propulsion shaft system can be protected more reliably.

1 is a system diagram illustrating a schematic configuration of an internal combustion engine for ships.
It is a figure which illustrates the schematic structure of the propulsion shaft system of the internal combustion engine for ships.
3 : is a figure which exemplifies about the increase of the rotation speed by a force.
Fig. 4 is a diagram exemplifying the continuous use prohibited range.
5 is a flowchart illustrating an operation sequence of the biasing device.
Fig. 6 is a view corresponding to Fig. 1 showing a modified example of the internal combustion engine for ships.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described based on drawing. Here, the following description is an example. 1 is a system diagram illustrating a schematic configuration of a marine internal combustion engine (hereinafter simply referred to as "engine 1"). In addition, FIG. 2 is a figure which illustrates the schematic structure of the propulsion shaft system S of the engine 1. As shown in FIG.

The engine 1 is an in-line multi-cylinder marine diesel engine provided with a plurality of cylinders 11 . This engine 1 is comprised as a single flow scavenging-air type two-stroke engine, and is mounted on large ships, such as an oil tanker, a container ship, and an automobile carrier. As shown in FIG. 2, the crankshaft 19 which is the output shaft of the engine 1 is connected to the propeller 18 via the flywheel (inertia wheel) 13 and the propulsion shaft system S, and the engine 1 As it operates, its output is transmitted to the propeller 18, configured to propel the vessel.

The engine 1 is also configured as an engine with a supercharger. That is, as shown in FIG. 1 , the engine 1 includes a main engine 10 having a plurality of cylinders 11 , and an intake passage 20 and an exhaust passage 30 connected to the main engine 10 . and an exhaust turbine supercharger 40 operated by exhaust flowing through the exhaust passage 30 in addition.

(1) Overall configuration

Hereinafter, the main part of the engine 1 is demonstrated.

As described above, the main engine 10 has a plurality of cylinders 11 (six cylinders 11 are exemplified in FIG. 1 ). In each cylinder 11, a piston (not shown) is respectively inserted reciprocally. The combustion chamber 12 is partitioned for each cylinder 11 by the inner wall of each cylinder 11, the ceiling surface of a cylinder head (not shown), and the top surface of a piston.

The main engine 10 according to the present embodiment is configured to start by receiving air pressure. Specifically, a pneumatic starting device 50 is connected to the main engine 10 of the engine 1 , and the starting device 50 is a starting valve 51 for supplying compressed air to each cylinder 11 . ), an air control valve 53 that controls the opening and closing of each starting valve 51, and a flame arrester ( 52) is provided.

In detail, the starting valve 51 is configured for each cylinder 11, and is in the middle of the flow path from the air source 61 to each cylinder 11, which will be described later (specifically, the downstream end of the main flow path 63a). ) is composed of Specifically, the starting valve 51 according to the present embodiment accommodates the starting piston connected to the valve rod on the lower end side while air is supplied to the top surface of the upper end side. By applying air pressure to the top surface of the starting piston to push down the valve rod connected to the starting piston, the starting valve 51 can be opened. On the other hand, by lowering the air pressure acting on the top surface of the starting piston to push up the valve rod, the starting valve 51 can be closed. By opening the starting valve 51 , the compressed air for starting supplied from the air source 61 (hereinafter referred to as “starting air”) can be supplied to each cylinder 11 . Accordingly, the piston of each cylinder 11 is pushed down by the compressed air, so that rotational motion can be generated in the crankshaft 19 .

In the starting valve 51 illustrated in FIG. 1 , the air pressure acting on the top surface of the starting piston is controlled by the control air supplied through a pipe independent of the starting air. That is, when the control air is supplied to the inside of the starting valve 51 (specifically, the top surface of the starting piston), the aforementioned valve rod descends and the starting valve 51 is opened, while the starting valve 51 When the control air is discharged from the inside of the valve rod rises and the starting valve 51 is closed. This supply of air for control is controlled by an air control valve (53).

Specifically, the air control valve 53 is configured to control the opening and closing of each starting valve 51 by distributing control air to each starting valve 51 . Specifically, the air control valve 53 according to the present embodiment is composed of a mechanical control valve comprising a helical drive gear, a rotary plate, a gear bearing, etc., and when compressed air is supplied to the air control valve 53, the rotary plate As the lights operate, compressed air is distributed to each starting valve 51 at a timing according to the ignition sequence of each combustion chamber 12 . The compressed air thus distributed, as the above-described control air, can control the vertical movement of the valve rod of each starting valve 51 , furthermore, the opening and closing of each starting valve 51 .

The flame arrester 52 is a so-called backfire prevention device, and as shown in FIG. 1, it is comprised in the direct upstream of each starting valve 51. As shown in FIG. By configuring the flame arrester 52, when the starting valve 51 fails and does not close, and the valve open state is unintentionally maintained, the flame due to combustion in the cylinder 11 flows back into the compressed air conduit. it can be prevented

Here, the air supplied from the air source 61 is configured to be used for purposes other than starting the main engine 10 . The air source 61 constitutes a pneumatic circuit 60 which will be described later.

As shown in FIG. 1 , in the main engine 10 , a scavenging air trunk 10a for supplying scavenging air to the combustion chamber 12 and exhaust gas (exhaust gas) from the combustion chamber 12 are discharged. An exhaust manifold 10b is connected. The main engine 10 is connected to the intake passage 20 through the scavenging air trunk 10a, and is connected to the exhaust passage 30 through the exhaust manifold 10b.

In the intake passage (20), a compressor (41) for supercharging the air flowing through the intake passage (20) sequentially from the upstream side, and an air cooler (21) configured to cool the air supercharged by the compressor (41) are arranged do. The air which has passed through the air cooler 21 reaches the combustion chamber 12 via the scavenging-air trunk 10a mentioned above.

On the other hand, in the exhaust passage 30, a turbine 42 driven and connected to the compressor 41 in order from the upstream side, and a Urea SCR system 90 for purifying exhaust are configured. The exhaust gas discharged from the combustion chamber 12 flows into the exhaust passage 30 through the exhaust manifold 10b described above, and passes through the turbine 42 and the urea SCR system 90 in sequence.

The exhaust turbine supercharger (40) has a compressor (41) configured in an intake passage (20) and a turbine (42) configured in an exhaust passage (30). The compressor 41 and the turbine 42 are connected and rotate in synchronization with each other. When the compressor 41 is rotationally driven by the exhaust gas passing through the turbine 42, the air passing through the compressor 41 can be supercharged.

In addition, the engine 1 according to the present embodiment includes an EGR (Exhaust Gas Recirculation) system 80 for circulating exhaust. In the example shown in FIG. 1 , the EGR system 80 is configured as a so-called high-pressure EGR system, and includes a portion downstream of the compressor 41 in the intake passage 20 and a turbine 42 in the exhaust passage 30 . It becomes a structure provided with the EGR passage 81 formed by connecting the upstream part of the. In this EGR passage 81, a first EGR valve 82 that opens and closes the EGR passage 81 sequentially from the upstream side in the flow direction of the circulated exhaust (hereinafter, also referred to as "EGR gas"), and the EGR gas An EGR scrubber 83 for removing soot, sulfur oxides (SO _x ), etc., an EGR cooler 84 for cooling the EGR gas, an EGR blower 85 for boosting the EGR gas pressure, and EGR A second EGR valve 86 for opening and closing the passage 81 is provided.

Further, the engine 1 according to the present embodiment includes the above-described element SCR system 90 in order to purify the exhaust. In the example shown in Fig. 1, the urea SCR system 90 is constituted as a so-called low-pressure SCR system, and the SCR unit 91 constituted at a site downstream of the turbine 42 in the exhaust passage 30, and the exhaust passage ( 30) and bypasses the turbine 42 and leads to the SCR unit 91, and a bypass valve 93 configured in the bypass passage 92 to open and close it. Here, the SCR unit 91 is an example of "exhaust purifying device".

Although not shown in detail, the SCR unit 91 includes a urea injector for injecting urea into the exhaust passage 30, a Selective Catalytic Reduction (SCR) catalyst for purifying exhaust by using the urea injected from the urea injector, It has a slip catalyst that oxidizes and purifies unreacted ammonia discharged from the SCR catalyst. Here, the SCR catalyst is configured to be activated at a predetermined temperature or higher, and when activated, urea is hydrolyzed to produce ammonia, and the ammonia can be reacted (reduced) with NO _x in exhaust to purify it.

That is, in order for the urea SCR system 90 to exhibit the purification performance, it is necessary to warm-up the SCR catalyst up to the predetermined temperature or higher. Therefore, when it is required to sufficiently activate the SCR catalyst, such as immediately after starting the main engine 10 , the bypass valve 93 is opened so that the exhaust gas bypasses the turbine 42 . In this case, the higher temperature exhaust can be introduced into the SCR unit 91 as much as energy required for the operation of the turbine 42 is saved. By the high-temperature exhaust introduced in this way, an early warm-up operation of the SCR catalyst becomes possible (so-called extraction operation). In addition, it is configured such that, when maintenance of the active state of the SCR catalyst is required not only immediately after starting of the main engine 10 but also during normal operation (normal operation), the extraction operation is appropriately executed.

In addition, the pneumatic circuit 60 has, as a main component, an air source 61 in which compressed air for starting the main engine 10 is accumulated, and a compressor 62 for replenishing the air source 61 with air. and an air flow path 63 for introducing air from the air source 61 to the main engine 10 (specifically, the starting device 50).

The air source 61 is configured as a so-called starting air reservoir, and is pressurized and filled with air for starting the main engine 10 . The air source 61 is comprised in two or more pieces (two pieces in the example shown in FIG. 1) according to the size of the main engine 10. As shown in FIG. Each air source 61 communicates with each other as shown in FIG. These air sources (61) are configured to supply compressed air to the starting device (50) via an air flow path (63) when the main engine (10) is started.

The air flow path 63 is a main flow path 63a formed by connecting the air source 61 and the starting device 50, and a first floating path 63b and a second flow path branched at an intermediate portion of the main flow path 63a. It has a floating path 63c. In addition, the biasing flow path 71 is connected to an intermediate part from the branch to the first floating path 63b and the second floating path 63c to the starting device 50 in the main flow path 63a.

Among the flow paths constituting the air flow path 63 , the main flow path 63a is a flow path through which the starting air supplied to the starting device 50 circulates. The main flow path 63a branches into a flow path for supplying starting air to each cylinder 11 in the vicinity of the starting device 50 and a flow path for supplying control air to each starting valve 51 . The former flow path branches further according to the number of cylinders and reaches each cylinder 11 via the flame arrester 52 and the starting valve 51 . On the other hand, the latter flow path branches off from the air control valve 53 and reaches the starting valve 51 of each cylinder 11 .

Further, the first floating path 63b is a flow path through which air (hereinafter, also referred to as "control air") for controlling each actuator constituting the main engine 10, such as an exhaust valve of the main engine 10, flows. And, the second floating path 63c is a flow path through which air supplied to tools used in the ship (hereinafter, also referred to as “working air”) flows.

Here, the pressure of the starting air of the main flow passage 63a is relatively high (about 25 to 30 bar), whereas the air for control or the working air is required to have a lower pressure (about 7 to 9 bar). Then, the some pressure reducing valve 64 is comprised in the 1st floating path 63b and the 2nd floating path 63c.

Moreover, in order to suppress rusting of each actuator, it is calculated|required so that moisture may not be contained in the air for control as much as possible. Then, on the downstream side of the pressure reducing valve 64 in the 1st floating path 63b, the air dryer 65 is comprised.

The pneumatic circuit 60 further includes a biasing device 70 configured to add to the supercharging by the exhaust turbine supercharger 40 . The biasing device 70 can supply the biasing air (hereinafter, also referred to as “pressured air”) to the compressor 41 of the exhaust turbine supercharger 40 through the biasing flow passage 71 .

Here, the biasing flow path 71 is configured to branch from the air flow path 63 to reach the exhaust turbine supercharger 40 . In detail, as shown in FIG. 1 , the biasing flow path 71 according to the present embodiment is a branching portion from the air flow path 63 to the first floating path 63b and the second floating path 63c. Although it is a downstream side, it branches at the site|part upstream rather than the connection part with the starting device 50. In addition, the downstream end of the flow path 71 for biasing is connected to the compressor 41 of the exhaust turbine supercharger 40 .

Specifically, the biasing device 70 includes the above-mentioned biasing flow path 71 and various members configured in the biasing flow path 71 . Specifically, in the biasing flow path 71, an on/off valve 72 for blocking the biasing flow path 71 when the biasing device 70 is not operated, for example, sequentially from the upstream side in the flow direction of the biasing air. A regulator 73 for decompressing the starting air, an on/off valve 74 for opening and closing the pressure flow passage 71, and an air filter 75 for filtering the pressure air are configured.

Here, the on-off valve 74 is configured as a pneumatic ball valve, and is configured to be controlled by the control air supplied through the first floating path 63b. Accordingly, the first floating passage 63b is further branched and configured to supply air for control to the on/off valve 74 via the branch passage 76 . This branch flow path 76 is configured as a flow path from the downstream side of the air dryer 65 in the first floating path 63b to the on/off valve 74, and is configured to be opened and closed by a solenoid valve 77. .

The solenoid valve 77 is configured to open and close based on a control signal input from the outside. When the solenoid valve 77 is in an open state, control air is supplied to the on-off valve 74 to open the on-off valve 74 . On the other hand, when the solenoid valve 77 is in a closed state, this on-off valve 74 can be maintained in a closed state, without supplying air for control to the on-off valve 74. As shown in FIG.

As shown in FIG. 2, the propulsion shaft system S transmits power to the propeller 18 from the main engine 10 (specifically, the crankshaft 19), and is comprised so that the propeller 18 may be rotated. do. Specifically, the propulsion shaft system (S) according to the present embodiment is connected to the crankshaft (19), the thrust shaft (15) receiving a thrust force generated when the ship propels, and the propeller (18) inserted into the stern tube and a propeller shaft 17 on which is mounted, and an intermediate shaft 16 connecting the thrust shaft 15 and the propeller shaft 17 . Here, the thrust shaft 15 which concerns on this embodiment is incorporated in the main engine 10 similarly to the crankshaft 19 so that FIG. 2 may show.

Accordingly, when diesel fuel is burned in each combustion chamber 12 of the main engine 10 , the crankshaft 19 rotates with the reciprocating motion of the piston inserted in each cylinder 11 . The rotation of the crankshaft 19 is transmitted to the thrust shaft 15 , the intermediate shaft 16 , and the propeller shaft 17 while being smoothed by the flywheel 13 to rotate the propeller 18 .

As described above, the internal combustion engine for ships (engine 1) according to the present embodiment is a large diesel engine configured to be mounted on a large ship. To this end, the engine 1 is provided with a plurality of control units 101 and 102 in order to control a ship on which the main engine 10 is mounted. Specifically, the plurality of control units 101 and 102 are each configured as a remote control system (RCS), and the control unit 101 configured in the bridge (B) of the ship, and the engine room (E). It has a control unit 102 configured in the.

Control handles 101a and 102a for changing the engine speed (revolution speed) of the main engine 10 are configured in each of the control units 101 and 102 . Each of the steering handles 101a and 102a is configured as a so-called telegraph lever, and by operating it, a target value of the rotation speed of the main engine 10 can be set.

Moreover, in the vicinity of the flywheel 13, the rotation speed sensor 14 which detects the rotation speed of the main engine 10 by monitoring the rotational motion of this flywheel 13 is comprised. The detection result by the rotation speed sensor 14 is comprised so that it may be displayed on the display system (not shown) installed in the bridge B and the engine room E. The sailor can operate the steering wheels 101a and 102a while referring to the display contents of the display system.

When a target value of the rotation speed is set by the respective steering wheels 101a and 102a, a signal corresponding to the setting is transmitted to a Speed Control System (SCS) 103 . In the speed control system 103, the amount of fuel required to realize the target value of the rotation speed is determined, and a signal corresponding to the determined amount of fuel is transmitted to an actuator such as a fuel injection valve. In this way, by operating the steering wheel 101a, 102a, the rotation speed of the main engine 10 can be controlled.

Here, the detection result by the rotation speed sensor 14 is input not only to the above-described display system but also to the control units 101 and 102 and the speed control system 103 as an electric signal indicating the detection result. Each of the units 101 to 103 can control the solenoid valve 77 based on the electric signal input in this way.

In addition, in order to respond to an emergency, etc., the main engine 10 is further configured with another control unit (not shown). This control unit is installed in the vicinity of the main engine 10, unlike the control units 101 and 102 configured as a remote control system, so that the crew can operate it while visually checking the behavior of the main engine 10. has been

Moreover, in the vicinity of the bridge B, the engine compartment E, and the main engine 10, the buttons 201, 202, 203 for operating the biasing device 70, respectively are comprised. These buttons 201, 202, and 203 are configured as operating devices independent of the control handles 101a and 102a, respectively, and are configured to receive an operation input (specifically, a pressing operation) by a crew member. When any one of the plurality of buttons 201, 202, 203 receives an operation input, a control signal is output to the solenoid valve 77 constituting the biasing device 70, and the solenoid valve 77 transmits this control signal is configured to receive and open the valve. These buttons 201, 202, and 203 each exemplify "manipulation section".

Moreover, the timer 204 is interposed in the electric circuit formed by connecting each button 201, 202, 203 and the solenoid valve 77. As shown in FIG. The timer 204 can close the solenoid valve 77 by switching the timer contact when a predetermined set time has elapsed after the buttons 201, 202, and 203 are pressed.

(2) Operation of the biasing device

The biasing device 70 configured as described above is used, for example, at the time of acceleration of the main engine 10 .

Specifically, a control signal output by pressing any one of the plurality of buttons 201, 202, 203 is input to the solenoid valve 77, and when the valve is opened, the control air flows through the branch flow path 76 to the on/off valve It is supplied to (74), and this on-off valve (74) is in an open state. Then, the starting air flows from the main flow path 63a into the pressure flow path 71, is decompressed by the regulator 73, and filtered by the air filter 75, the exhaust turbine supercharger 40 of the compressor (41). The biasing air supplied to the compressor 41 assists in supercharging by the exhaust turbine supercharger 40 by adding to the rotational drive of the compressor 41 .

Here, when the set time of the timer 204 elapses, the solenoid valve 77 is automatically closed. Therefore, the biasing device 70 according to the present embodiment can bias the exhaust turbine supercharger 40 over a predetermined time (timer 204 set time).

3 : is a figure which exemplifies the increase of the rotation speed by a force. Specifically, Fig. 3 shows a case in which the biasing device 70 is not operated (refer to the broken line in Fig. 3) when the acceleration of the main engine 10 is started at time t0, and the biasing device 70 is operated It is a figure which compares and shows the change amount of rotation speed in this case (refer to the solid line in FIG. 3).

As shown in FIG. 3 , the biasing device 70 adds to the supercharging by the exhaust turbine supercharger 40, thereby operating the exhaust turbine supercharger 40 responsively at the time of accelerating the ship, and furthermore, the main engine ( 10) can quickly increase the number of rotations.

In recent years, in order to cope with the tightening of regulations of CO ₂ emission based on EEDI, with respect to the size (weight of goods) of a ship, an internal combustion engine with a lower output tends to be used than before.

However, when a low-output internal combustion engine is used, since its displacement is reduced, for example, even if it is attempted to accelerate rapidly, the turbocharger turbine does not rotate responsively, and the rotation speed of the main engine may not sufficiently follow.

4 shows the relationship between the number of revolutions of the main engine 10 and the torsional vibration stress, and, in particular, illustrates the continuous use prohibited range (as described above, this range is also referred to as a "bard range") It is a drawing.

In general, in a large marine diesel engine such as a two-stroke diesel engine, the explosive force due to combustion of diesel fuel and the inertial force due to the reciprocating motion of the cylinder become the vibratory force, and the propulsion shaft system S of the main engine 10 is torsional vibration is generated. As shown by the solid line in Fig. 4, the torsional vibration generated in the propulsion shaft system S reaches resonance at a predetermined rotational speed. As is well known, the number of revolutions causing resonance exists over a plurality of depending on the configuration of the engine 1 . Among these, resonance, which becomes a problem during the operation of the engine 1, is due to the torsional vibration of the 1st node (node) nth order (n is the number of cylinders) in the case of the 4-7 cylinder engine 1 . In the following description, the rotation speed causing such resonance will be referred to as "resonance rotation speed", and the symbol "r0" will be given. The torsional vibration stress shown in Fig. 4 is maximized at this resonance rotation speed r0.

In general, the torsional vibration stress acting on the propulsion shaft system (S) is limited by the permissible stresses (τ1, τ2) specified in the Rules for the Classification. There are two types of allowable stresses τ1 and τ2, both of which are determined based on the type, shape, size, etc. of the thrust shaft 15, intermediate shaft 16, and propeller shaft 17 constituting the propulsion shaft system S. do.

Among these, the 1st allowable stress tau 1 shows that the main engine 10 can be used continuously according to the rotation speed, if the torsional vibration stress which generate|occur|produces at a certain rotation speed is tau 1 or less. On the other hand, when the torsional vibration stress exceeds tau 1 as when the rotational speed is near the resonance rotational speed r0, it becomes difficult to protect the propulsion shaft system S from fatigue failure at the rotational speed.

Therefore, when there is a possibility that the torsional vibration stress exceeds τ1, the bard range is set before and after the resonance rotation speed r0. that is required Here, although the details are omitted, the bard range is set based on the resonance rotation speed r0 and the ratio of the resonance rotation speed r0 to the continuous maximum rotation speed. In the example shown in FIG. 4, when the rotation speed of the main engine 10 is r, the range of r1<=r<r2 corresponds to a bard range. As revealed in the description so far, the bard range includes the resonance rotation speed r0 (ie, r1≤r0≤r2).

In addition, the second allowable stress τ2 represents an allowable limit that should not be exceeded even when passing through the bard range. That is, even if the torsional vibration stress temporarily exceeds τ1, it is not allowed to exceed τ2. Although omitted in detail, τ2 is set in consideration of the repeated action of the stress generated when passing through the bard range on the propulsion shaft system S.

In this way, when operating the engine 1 and a ship on which the engine 1 is mounted, the bard based on the first allowable stress τ1 in a state in which the design does not exceed the second allowable stress τ2. It is desired to pass the range as quickly as possible. In particular, in order to respond to the latter request, it is required to accelerate the main engine 10 as rapidly as possible.

Moreover, like the engine 1 shown in FIG. 1, when it is set as the structure provided with a high-pressure EGR system (EGR system 80) or a low-pressure SCR system (element SCR system 90), the EGR passage 81 is interposed. And the exhaust flow rate passing through the turbine 42 is reduced by refluxing the exhaust or allowing the exhaust to bypass the turbine 42 through the bypass passage 92 . This is inappropriate to ensure the responsiveness of the exhaust turbine supercharger 40 .

Therefore, as in the engine 1 according to the present embodiment, it is conceivable to configure such that the supercharging by the exhaust turbine supercharger 40 is added by auxiliary supply of pressurized air by the biasing device 70 , but the present application As a result of repeated studies by the inventor(s), it was found that there is room for improvement in protecting the propulsion shaft system S from fatigue failure.

That is, in order to pass through the bard range as quickly as possible, the biasing device 70 must be utilized. However, if the biasing device is configured to start with the buttons 201, 202, and 203, the bias is executed at a timing independent of the bard range. As a result, there is a risk of becoming at a disadvantage in passing the bard range.

Accordingly, in the engine 1 according to the present embodiment, the controller controls the biasing device 70 based on the detection result by the rotation speed sensor 14 . The "controller" herein may be any one of the respective control units 101 and 102 and the speed control system 103, or a combination thereof. Alternatively, the ECU 104 may be used as a controller as in a modified example (refer to FIG. 6) described later. For simplicity, in this specification, a case in which each of the control units 101 and 102 is used as a controller will be described.

Then, each of the control units 101 and 102 as a controller, when the main engine 10 is accelerated, when the rotation speed of the main engine 10 (engine rotation speed) rises to within a predetermined range, this biasing device By outputting a control signal to 70, the biasing device 70 is actuated. At this time, the biasing device 70 continues the biasing to the exhaust turbine supercharger 40 over a predetermined period of time (a time set equal to or independently of the timer 204 ).

In addition, the "predetermined range" serving as an index for starting the bias is set in advance and stored in advance in the memory of each of the control units 101 and 102 or the like. This predetermined range is defined so as to include the resonance rotation speed r0 of the propulsion shaft system S in the main engine 10 . In more detail, it is preferable to set the predetermined range to include the aforementioned bard range, and more preferably, it can be set to approximately coincide with the bard range.

In the engine 1 according to the present embodiment, it is set so that the predetermined range and the bard range completely coincide. That is, when the rotation speed of the main engine 10 is r, r1≤r≤r2 becomes a predetermined range.

Thus, in the engine 1 which concerns on this embodiment, it is comprised so that the biasing by the biasing device 70 may be performed when the rotation speed rises to the bard range range. Thereby, it is possible to pass through the bard range reliably and as quickly as possible. Thereby, the propulsion shaft system can be protected more reliably.

(3) Example of control of the biasing device

5 is a flowchart illustrating an operation sequence of the biasing device 70 .

First, with the operation of the engine 1 , the rotation speed sensor 14 monitors the rotation speed of the main engine 10 . Specifically, the rotation speed sensor 14 detects the rotation speed and inputs the detection result to the respective control units 101 and 102 (step S1).

Then, each of the control units 101 and 102 determines whether or not the rotation speed detected in step S1 is within a range of a predetermined range (bard range in this example) (step S2). If this determination is NO (step S2: NO), the flow returns to step S1 to continue monitoring the rotation speed, while if YES (step S2: YES), proceeds to step S3 to start the biasing device 70 make it Here, although omitted in FIG. 5, determination of YES in step S2 is limited to the time of acceleration of the main engine 10. FIG. Accordingly, when the main engine 10 is decelerating, the control process returns to step S1, even if the number of revolutions detected in step S1 is within the range of the bard range.

Therefore, in the engine 1 according to the present embodiment, in order to determine whether or not the main engine 10 is accelerating, the steering units 101 and 102 monitor the states of the steering wheels 101a and 102a, respectively. configured to do Specifically, each of the control units 101, 102 determines whether the steering wheel 101a, 102a has been operated from the low speed side to the high speed side, and makes a determination according to step S2 based on the determination result.

In step S3, when the biasing device 70 is started, the biasing air is auxiliaryly supplied to the compressor 41 of the exhaust turbine supercharger 40, and it can add to the rotation of the compressor 41 (step S4). When the preset predetermined time has not elapsed (step S5: NO), the biasing device 70 continues the biasing to the exhaust turbine supercharger 40, while the set time of the timer 204 has elapsed (step S5: NO). At S5: YES), the force to the exhaust turbine supercharger 40 is stopped (step S6).

《Other embodiments》

In the above embodiment, although the configuration in which the opening and closing of the start valve 51 is controlled by the air control valve 53 has been described, it is not limited to this configuration. Instead of configuring the air control valve 53, the opening and closing of the starting valve 51 is mechanically controlled or, for example, as shown in FIG. 6, electrically controlled using a solenoid valve 59 You can do it. In the example shown in FIG. 6 , opening and closing of the starting valve 51 can be controlled based on the electric signal output from the ECU 104 .

In addition, in the said embodiment, although the structure provided with the EGR system 80 comprised as a high-pressure EGR system was illustrated, it is not limited to this structure. For example, an EGR system (so-called so-called EGR system) configured to reflux exhaust between an upstream side portion of the compressor 41 in the intake passage 20 and a downstream portion of the turbine 42 in the exhaust passage 30 . A low-pressure EGR system) may be provided, or the EGR system itself may be omitted.

In addition, in the above embodiment, although the configuration provided with the element SCR system 90 configured as a low-pressure SCR system was exemplified, it is not limited to this configuration. For example, it is good also as a structure provided with the urea SCR system (so-called high-pressure EGR system) arranged on the upstream side of the turbine 42 in the exhaust passage 30 .

Moreover, although the timer 204 was comprised in the middle of the circuit from the button 201, 202, 203 to the solenoid valve 77 in the said embodiment, it is not limited to this structure. You may configure a timer individually for each button.

1: Engine (internal combustion engine for ships)
10: main engine
14: rotation speed sensor
20: intake passage
30: exhaust passage
40: exhaust turbine supercharger
41 : Compressor
42: turbine
61: air source
70: bias device
81: EGR passage
91: SCR unit (exhaust purifier)
92: bypass passage
101, 102: control unit (controller)
103: speed control system (controller)
S: Propulsion shaft system
r0: number of resonance rotations

Claims (6)

2 administrative departments;
an intake passage for introducing air into the main engine;
an exhaust turbine turbocharger configured to supercharge the air flowing through the intake passage;
a biasing device configured to supplement the supercharging by the exhaust turbine supercharger by supplying air to the exhaust turbine supercharger;
a sensor for detecting the engine speed of the main engine;
a controller for controlling the biasing device based on the detection result by the sensor;
When the controller accelerates the main engine,
When the engine speed is less than a predetermined range, the biasing device is deactivated,
When the engine speed rises to within the predetermined range, operating the biasing device,
The biasing device is
When the engine speed of the main engine rises to within the predetermined range, the engine speed is rapidly accelerated compared to when the biasing device is not in operation by adding it to the exhaust turbine supercharger over a predetermined period of time,
After the lapse of the predetermined time, the force to the exhaust turbine supercharger is stopped,
The resonance rotation speed of the propulsion shaft system in the main engine is prescribed so as to fall within the range of the predetermined range.
Marine internal combustion engine, characterized in that. The method of claim 1,
and an exhaust passage for introducing exhaust exhaust from the main engine;
The exhaust turbine supercharger includes a compressor configured in the intake passage, and a turbine configured in the exhaust passage,
The biasing device is configured to supply air to the compressor so as to add to the rotational driving of the compressor.
Marine internal combustion engine, characterized in that. 3. The method of claim 2,
and an EGR passage formed by connecting a downstream portion of the compressor in the intake passage and an upstream portion of the turbine in the exhaust passage.
Marine internal combustion engine, characterized in that. 4. The method according to claim 2 or 3,
an exhaust purification device configured at a downstream side of the turbine in the exhaust passage and activated at a predetermined temperature or higher;
In the exhaust passage, a bypass passage bypassing the turbine and leading to the exhaust purification device is configured.
Marine internal combustion engine, characterized in that. delete delete

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