KR20160105794A - Engine system - Google Patents

Abstract

The engine system is operated in a state in which the main turbocharger is operated while the main turbocharger and the auxiliary turbocharger are operated while closing the auxiliary turbine inlet valve and the auxiliary compressor outlet valve and stopping the auxiliary turbocharger to reduce the number of operations of the turbocharger, And the windshield valve is opened when the outlet pressure of the auxiliary compressor is higher than the reference pressure at the time of stopping and the windshield valve is closed when the outlet pressure of the auxiliary compressor is lower than the reference pressure at the time of stoppage .

Description

Engine system {ENGINE SYSTEM}

The present invention relates to an engine system having a plurality of superchargers and capable of changing the number of superchargers driven according to driving conditions.

Generally, in an engine system having a supercharger, a supercharger is selected so that an efficient operation can be performed when the engine body is at a high load. However, from the viewpoint of fuel economy and the like, there are cases where the main engine and the auxiliary turbochargers are provided with two turbochargers in an engine system in which the engine main body is often operated at a heavy load and a low load. In this engine system, both the main supercharger and the auxiliary supercharger are operated when the engine main body is operated at a high load, and only the main supercharger is operated when the engine main body is operated under heavy load and low load. With this configuration, efficient operation is possible not only when the engine body is operated at a high load, but also when it is operated at a heavy load and a low load.

Further, in the case of an engine system having an EGR unit for recirculating exhaust gas to the engine main body, the amount of exhaust gas to be supplied to the turbocharger is reduced during EGR operation than during normal operation, Changing the logarithm allows efficient operation while preventing surge of the supercharger.

In order to continue driving the engine and reduce the number of superchargers, the main supercharger must be operated while the auxiliary supercharger is stopped. In this case, since the outside air boosted by the main turbocharger is backwashed to the auxiliary turbocharger, a valve is provided on the compressor outlet side of the auxiliary turbocharger in the engine system for changing the number of the supercharger. Closing this valve can prevent reverse flow. However, when the auxiliary turbocharger continues to operate with this check valve closed, the back pressure of the auxiliary turbocharger increases, resulting in a surge. Therefore, in such an engine system, a blowing pipe for guiding the air between the compressor of the auxiliary turbocharger and the check valve for counterflow to the outside, and a windshield valve installed in the blowing pipe are provided. Also, before the backflow prevention valve is closed, the windshield valve is opened to prevent the occurrence of surge (see Patent Documents 1 to 3).

On the other hand, Patent Document 2 discloses a marine diesel engine having a check valve that is opened when the outlet pressure of the compressor portion of the auxiliary exhaust turbine turbocharger is equal to or greater than the pressure of the supply manifold. In the invention described in Patent Document 2, although it is possible to prevent the backflow phenomenon, it is not judged whether or not the condition is such that the surge can occur. In the invention described in Patent Document 3, the check valve is replaced with a control valve in the invention described in Patent Document 2. This control valve is opened when the differential pressure between the outlet pressure of the compressor section and the pressure of the supply manifold becomes a predetermined value or less. In the invention described in Patent Document 3, it is not judged whether or not the condition is capable of causing a surge. There is a limit to the control because it is indirectly controlled from the causal relationship with the number of in-pipe states at a place other than the surge generation place of the auxiliary exhaust turbine supercharger called differential pressure before and after the valves in the piping.

Japanese Patent Application Laid-Open No. 60-166716 Japanese Patent Application Laid-Open No. 2009-167799 Japanese Patent Application Laid-Open No. 2011-47393

As described above, in the conventional engine system, in order to reliably prevent the surge, the wind-blowing valve is opened early and then the backflow prevention valve is closed. Accordingly, air that can be supplied to the engine body is discharged to the outside, and as a result, the pressure of the scavenging gas supplied to the engine body (scavenging pressure) is reduced, and the engine main body can not be efficiently operated.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide an engine system capable of preventing a decrease in efficiency of an engine main body while preventing occurrence of a surge in a supercharger when changing the number of superchargers driven .

An engine system according to an embodiment of the present invention includes an engine main body, at least one main turbocharger having a main turbine and a main compressor, and an auxiliary turbine and an auxiliary compressor disposed in parallel with the main turbocharger with respect to the engine main body, An auxiliary compressor outlet valve provided at an outlet side of the auxiliary compressor and an auxiliary compressor outlet valve disposed at an outlet side of the auxiliary compressor for supplying the outdoor air boosted by the auxiliary compressor to an upstream side of the auxiliary compressor outlet valve And a control device, wherein the control device controls the main supercharger and the auxiliary supercharger in a state where the main supercharger and the auxiliary supercharger are in a stopped state, Turbine inlet valve and said auxiliary compressor outlet valve to close said auxiliary turbocharger When the auxiliary compressor outlet pressure is higher than the reference pressure at the time of stopping, the opening degree of the windshield valve is set to a predetermined value And to reduce the opening degree of the windshield valve when the auxiliary compressor outlet pressure is lower than the stopping reference pressure.

According to this configuration, the windshield valve is closed when the auxiliary compressor outlet pressure is lower than the reference pressure at the time of stoppage. That is, when the possibility of occurrence of a surge is small, the wind-blowing valve is closed and the outdoor air that has been boosted by the auxiliary compressor is supplied to the engine main body. As a result, the raised air in the auxiliary compressor is prevented from being unnecessarily discharged to the outside, thereby suppressing the decrease in the pressure of the engine main body. As a result, it is possible to suppress the decrease in the efficiency of the engine body when the number of superchargers is reduced.

In addition, in the engine system, when the opening degree of the windshield valve is increased, the control device is configured to reduce the increase amount of the windshield valve as the difference between the outlet pressure of the auxiliary compressor and the reference pressure at the stop is decreased good.

According to this configuration, when the operating point of the auxiliary compressor is not near the surge region, the amount of increase in opening degree of the windshield valve is reduced. That is, when the possibility of occurrence of the secondary compressor surge is not great, the outside air which is boosted by the auxiliary compressor is not emitted to the outside. As a result, it is possible to efficiently operate the engine body by increasing the scavenging pressure while suppressing the occurrence of surge in the auxiliary compressor.

Further, an engine system according to an embodiment of the present invention includes an engine body, at least one main turbocharger having a main turbine and a main compressor, and an auxiliary turbine and an auxiliary compressor disposed in parallel with the main turbocharger, An auxiliary compressor outlet valve provided at an outlet side of the auxiliary compressor, and an auxiliary compressor outlet valve disposed at an outlet side of the auxiliary compressor, wherein the auxiliary compressor outlet valve is connected to the auxiliary compressor outlet valve And a control device for controlling the main supercharger to operate the main supercharger in a state where the main supercharger is operated and the auxiliary supercharger is operated Opening the auxiliary turbine inlet valve and the auxiliary compressor outlet valve, Wherein when the auxiliary supercharger is operated to increase the number of superchargers, a reference pressure during operation having a predetermined surge margin is determined based on the number of rotations of the auxiliary turbocharger, and when the auxiliary compressor outlet pressure is higher than the reference pressure during operation, And to decrease the opening degree of the windshield valve when the auxiliary compressor outlet pressure is lower than the reference pressure during the operation.

According to this configuration, when the outlet pressure of the auxiliary compressor is lower than the reference pressure during operation, the opening degree of the windshield valve is reduced. That is, when the possibility of occurrence of a surge is small, the opening degree of the windshield valve is reduced to supply the increased amount of air from the auxiliary compressor to the engine main body. As a result, the raised air in the auxiliary compressor is prevented from being unnecessarily discharged to the outside, thereby suppressing the decrease in the pressure of the engine main body. As a result, it is possible to suppress the decrease in the efficiency of the engine body when the number of superchargers is increased.

In addition, in the engine system, the control device may be configured to reduce an increase in the opening degree of the windshield valve as the difference between the outlet pressure of the auxiliary compressor and the reference pressure during operation increases as the opening degree of the windshield valve increases .

According to such a configuration, when the operating point of the auxiliary compressor is not near the surge region, the increase amount of the opening degree of the windshield valve is reduced. That is, when the possibility of occurrence of the secondary compressor surge is not great, the outside air which is boosted by the auxiliary compressor is not emitted to the outside. As a result, it is possible to efficiently operate the engine body by increasing the scavenging pressure while suppressing the occurrence of surge in the auxiliary compressor.

In addition, in the engine system, when increasing the number of operations of the supercharger, the controller controls the opening of the auxiliary compressor outlet valve when the auxiliary turbocharger rotation speed becomes the predetermined switching rotation number or more after starting the opening of the auxiliary turbine inlet valve. And the switching rotation speed may be configured to be determined according to the engine load. The switching speed is not determined by comparing the outlet pressure of the auxiliary compressor with the scavenging pressure but the operating curve of the auxiliary compressor (the relationship between the auxiliary compressor flow rate and the outlet pressure of the auxiliary compressor) from the time immediately before opening of the auxiliary compressor outlet valve to the completion of the switching Predicting and considering that the secondary compressor does not generate a surge.

According to this configuration, since the auxiliary compressor outlet valve is closed until the number of rotations of the auxiliary turbocharger reaches the switching rotational speed when the number of superchargers is increased, the outside air boosted by the main compressor is not returned to the auxiliary compressor, Can supply. Therefore, the engine main body can be efficiently operated. In addition, since the switching revolution speed is determined according to the engine load, it is possible to operate the engine body more efficiently while preventing surge.

According to another aspect of the present invention, there is provided an engine system including an engine main body, at least one main turbocharger having a main turbine and a main compressor, and an auxiliary turbine and an auxiliary compressor disposed in parallel with the main turbocharger, An auxiliary compressor outlet valve provided at an outlet side of the auxiliary compressor, and an auxiliary compressor outlet valve disposed at an outlet side of the auxiliary compressor, wherein the auxiliary compressor outlet valve is connected to the auxiliary compressor outlet valve And a control device for controlling the main supercharger to operate the main supercharger in a state where the main supercharger is operated and the auxiliary supercharger is stopped, The auxiliary turbine inlet valve and the auxiliary compressor outlet valve are opened, When the auxiliary turbocharger is operated to increase the number of superchargers, the auxiliary turbine inlet valve is started to be opened with the wind turbine valve opened at a predetermined opening degree, and then the auxiliary turbocharger rotational speed becomes equal to or greater than a predetermined first switching rotational speed The start of the closing of the windshield valve and the opening of the auxiliary compressor outlet valve are started when the auxiliary turbocharger rotational speed becomes equal to or larger than the second switching rotational speed which is larger than the first switching rotational speed.

According to such a configuration, since the auxiliary compressor outlet valve starts to be opened in a state in which the windshield valve is closed to some extent, it is possible to prevent the outside air that is boosted by the auxiliary compressor from being discharged to the outside through the windshield. Further, it is possible to prevent the outside air that has been boosted by the main compressor from flowing backward to the auxiliary compressor. Therefore, the reduction of the efficiency of the engine main body can be suppressed.

Further, in the engine system, the control device determines a first switching operating point (a secondary compressor flow rate and an auxiliary compressor outlet pressure) of the subcompressor having a predetermined surge margin based on an engine load, The number of revolutions of the auxiliary turbocharger in the pressure curve passing through the operating point (the relationship between the auxiliary compressor flow rate and the auxiliary compressor outlet pressure at each revolution number of the auxiliary turbocharger) may be set to the first switching revolution number. The first switching revolution speed is not determined by comparing the outlet pressure of the auxiliary compressor with the scavenging pressure but the operation curve of the auxiliary compressor is predicted until just before starting opening of the auxiliary compressor outlet valve immediately before starting to close the windshield valve depending on the engine load And that the secondary compressor does not generate a surge.

According to this configuration, the first switching operating point is determined according to the engine load, and the first switching rotational speed is determined using the first switching operating point. Therefore, it is possible to control the opening and closing of the windshield valve without measuring the pressure such as the outlet pressure of the auxiliary compressor. Therefore, a pressure gauge for measuring the pressure, such as the outlet pressure of the subcompressor, is unnecessary depending on other conditions.

In addition, in the engine system, the control device may determine a second switching operating point of the sub-compressor having a predetermined surge margin based on the engine load, and determine a second switching operating point of the sub- And the rotation number may be the second switching rotation speed. The second switching revolution speed is not determined by comparing the outlet pressure of the auxiliary compressor with the scavenging pressure but is determined according to the engine load from the time immediately before the opening of the auxiliary compressor outlet valve to the completion of the opening of the auxiliary compressor Predicting and considering that the secondary compressor does not generate a surge.

According to this configuration, the second switching operating point is determined according to the engine load, and the second switching rotation speed is determined using the second switching operating point. Thus, it is possible to determine the timing at which to start opening the secondary compressor outlet valve without measuring the pressure, such as the secondary compressor outlet pressure. Therefore, a pressure gauge for measuring the pressure, such as the outlet pressure of the subcompressor, is unnecessary depending on other conditions.

Further, in the engine system, the control device acquires the main compressor outlet pressure when increasing the number of operations of the supercharger, and when the acquired auxiliary compressor outlet pressure is equal to or higher than the second switching rotation speed, It may be configured to start opening the auxiliary compressor outlet valve when the pressure is less than the auxiliary compressor outlet pressure at the operating point.

When determining the timing of opening the auxiliary compressor outlet valve in accordance with the engine load, there may be a case where the main compressor outlet pressure is higher than the expected pressure in a situation where the engine load suddenly fluctuates. When the main compressor outlet valve is opened, There is a possibility that the outside air that has been boosted in the second compressor flows back to the second compressor. On the other hand, in the above-described configuration, when the actual outlet pressure of the main compressor is obtained and there is a possibility of occurrence of the back flow, the auxiliary compressor outlet valve is not opened, so that the back flow can be prevented from occurring in the auxiliary compressor.

Further, in the engine system, the control device sets the same value as the obtained main compressor outlet pressure as the second switching pressure, and sets a value obtained by adding a predetermined flow rate to the auxiliary compressor flow rate generated by the surge at the second switching pressure 2 as the second switching operating point and the second switching operating point as the second switching operating point as the second switching operating point and the auxiliary turbocharger rotational speed of the pressure curve passing through the second switching operating point to the second switching The number of revolutions may be set.

According to such a configuration, since the second switching revolution speed is determined according to the main compressor outlet pressure without using the engine load, even if the number of auxiliary turbochargers is increased in a situation where the engine load suddenly fluctuates, reverse flow is prevented from occurring in the auxiliary compressor can do.

Further, in the engine system, the control device estimates the engine load on the basis of the acquired main compressor outlet pressure, and calculates a first switching operating point of the auxiliary compressor having a predetermined surge margin based on the estimated engine load And the auxiliary turbocharger rotational speed of the pressure curve passing through the first switching operating point may be the first switching rotational speed.

According to this configuration, since it is possible to determine the first switching rotation speed according to the main compressor outlet pressure, it is not necessary to directly acquire the engine load even when determining the first switching rotation speed as well as the second switching rotation speed. That is, since the acquisition of the engine load can be omitted in the control for increasing the number of operations, the engine system can be simplified in the case where the acquisition of the engine load can be omitted even in the operation number reduction control.

Further, in the engine system, the control device may be configured such that, when the windshield valve is closed, the amount of decrease in opening degree of the windshield valve decreases as the difference between the number of rotations of the auxiliary turbocharger and the first switching rotation speed decreases.

According to this configuration, when the possibility of occurrence of a surge in the auxiliary compressor is small, the windshield valve can be quickly closed, so that the efficiency reduction of the engine main body can be further suppressed.

As described above, according to the engine system, it is possible to prevent the efficiency of the engine main body from decreasing when changing the number of superchargers to be driven while preventing occurrence of surge in the supercharger.

1 is a schematic configuration diagram of the entire engine system according to the first embodiment.
2 is a block diagram of the control system of the engine system.
3 is a flowchart showing a method of controlling the number of supercharger drives.
4 is a time chart of the degree of opening of each valve at the time of controlling the number of supercharger operations.
5 is a graph showing the relationship between the surge line and the reference pressure at the time of stopping.
6 is a time chart of the auxiliary compressor outlet pressure and scavenging pressure.
7 is a flowchart showing a supercharger drive algebraic increase control method of the first embodiment.
8 is a time chart of the opening degree of each valve at the time of increasing the number of supercharger operation in the first embodiment.
9 is a graph showing the relationship between the engine load and the switching rotational speed.
10 is an overall schematic view of an engine system according to a modification of Fig.
11 is a flowchart showing the supercharger drive algebraic increase control method of the second embodiment.
12 is a time chart of the opening degree of each valve and the number of revolutions of the auxiliary supercharger in the supercharger drive algebraic increase control of the second embodiment.
13 is a graph showing the relationship between the engine load and the first switching pressure and the second switching pressure.
14 is a graph showing the relationship between the engine load, the first switching flow rate, and the second switching flow rate.
15 is a diagram for explaining a method for determining the first switching rotation speed and the second switching rotation speed in the second embodiment.
16 is a schematic configuration diagram of the entire engine system according to the third embodiment.
17 is a flowchart showing the supercharger drive algebraic increase control method of the third embodiment.
18 is a flowchart showing the supercharger drive algebraic increase control method of the fourth embodiment.
19 is a graph showing the relationship between the main compressor outlet pressure and the engine load.
20 is a diagram for explaining a method for determining the second switching rotation speed in the fourth embodiment.
21 is an overall schematic view of an engine system according to another modification of Fig.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same or equivalent elements are denoted by the same reference numerals throughout the drawings, and redundant explanations are omitted.

(Embodiment 1)

First, the first embodiment will be described.

≪ Overall configuration of engine system >

First, the entire configuration of the engine system 100 according to the present embodiment will be described. Fig. 1 is a schematic configuration diagram of the entire engine system 100. Fig. In Fig. 1, the broken line shown in bold indicates the flow of the exhaust gas, and the solid line shown in bold indicates the flow of the scavenging gas. 1, the engine system 100 includes an engine main body 10, a main turbocharger 20, a supplementary turbocharger 30, an auxiliary turbine inlet valve 41, an auxiliary compressor outlet valve 42, (43).

The engine main body 10 of this embodiment is a propulsion cycle of a ship, and is a large two-stroke diesel engine. The engine main body 10 is provided with an engine speed meter 11 (see FIG. 2) for measuring the number of revolutions (engine speed) of the engine main body 10. Further, the engine body 10 has a fuel supply device 12 (see Fig. 2) for adjusting the fuel injection amount. The engine main body 10 may be a four-stroke engine, a gas engine, or a gasoline engine. In the following description, "scavenge" may be replaced by "supply air" in the case of a four stroke engine.

The main supercharger 20 is a supercharger that is always operated regardless of the operating state of the engine body 10. [ The exhaust gas discharged from the engine body 10 is supplied to the main turbine 22 through the main exhaust pipe 21. The main turbine 22 is rotated by the energy of the supplied exhaust gas. The main turbine 22 and the main compressor 23 are connected by a connecting shaft 24 and the main compressor 23 is also rotated in accordance with the rotation of the main turbine 22. When the main compressor 23 rotates, the air (outside air) received from outside is boosted, and the boosted outside air is supplied to the engine main body 10 through the main exhaust pipe 25 as a scavenging gas.

The auxiliary turbocharger 30 is a supercharger that operates or stops according to the operating state of the engine body 10. [ The auxiliary turbocharger (30) is disposed in parallel with the main turbocharger (20) with respect to the engine body (10). The auxiliary turbocharger 30 may be of the same specification (capacity) as the main turbocharger 20 or may be of another specification. The exhaust gas discharged from the engine body 10 is supplied to the auxiliary turbine 32 through the auxiliary exhaust pipe 31. The auxiliary turbine 32 is rotated by the energy of the supplied exhaust gas. The auxiliary turbine 32 and the auxiliary compressor 33 are connected by a connecting shaft 34 and the auxiliary compressor 33 is also rotated in accordance with the rotation of the auxiliary turbine 32. When the auxiliary compressor 33 rotates, the air (outside air) taken in from the outside is boosted and the boosted outside air is supplied to the engine main body 10 through the auxiliary scavenge piping 35 and the main scavenge piping 25 as scavenge gases .

In this embodiment, the auxiliary scavenging pipe (35) is connected to the main scavenging pipe (25). An air cooler 50 for cooling the scavenging gas is provided downstream of the portion to which the auxiliary scavenging pipe 35 of the main scavenging pipe 25 is connected. However, when the air cooler 50 is installed for each of the turbochargers 20 and 30, the auxiliary exhaust pipe 35 is not connected to the main exhaust pipe 25 but is connected to the engine main body 10, Or may be directly connected to the terminal. The auxiliary turbocharger 30 is also provided with a auxiliary turbocharger rotational system 36 for measuring the number of revolutions of the auxiliary turbocharger 30 (auxiliary compressor 33). In the vicinity of the outlet of the auxiliary compressor 33, an auxiliary compressor outlet pressure gauge 37 for measuring the pressure of the outside air raised by the auxiliary compressor 33 (the outlet pressure of the auxiliary compressor) is provided.

The auxiliary turbine inlet valve 41 is a valve installed in the auxiliary exhaust pipe 31 and located at the inlet side of the auxiliary turbine 32. The auxiliary compressor outlet valve 42 is a valve located on the outlet side of the auxiliary compressor 33 and installed in the auxiliary furnace pipe 35. A ventilation piping (44) is connected to a part upstream of the auxiliary compressor outlet valve (42) of the auxiliary scavenging pipe (35). The ventilation piping (44) is a pipe for guiding the outside air raised by the auxiliary compressor (33) to the outside. The windshield valve 43 is provided in the windshield line 44. The auxiliary-turbine inlet valve 41 and the auxiliary-compressor outlet valve 42 of the above-mentioned valves are open / close valves that are switched to either fully closed or fully open in the present embodiment, but may be control valves capable of adjusting the opening degree. It takes some time to open and close the valves (see Fig. 4). On the other hand, the windshield valve 43 is a control valve which can adjust the opening degree in this embodiment. However, the windshield valve 43 may be controlled by an inching operation (operation by an open command / close command) as an open / close valve.

<Configuration of control system>

Next, the configuration of the control system of the engine system 100 will be described. Fig. 2 is a block diagram of the control system of the engine system 100. Fig. As shown in Fig. 2, the engine system 100 includes a control device 60 for controlling the entire engine system 100. As shown in Fig. The control device 60 is composed of, for example, a CPU, a ROM, a RAM, and the like.

The control device 60 is electrically connected to the engine rotation system 11, the fuel supply device 12, the auxiliary turret rotation system 36, and the auxiliary compressor outlet pressure gauge 37. The controller 60 acquires the engine speed, the fuel injection amount, the auxiliary turbocharger speed, and the outlet pressure of the auxiliary compressor in accordance with a signal received from these devices. The control device 60 controls various parts of the engine system 100 by performing various operations according to input signals from the respective devices. In the present embodiment, the control device 60 is electrically connected to the auxiliary turbine inlet valve 41, the auxiliary compressor outlet valve 42 and the windshield valve 43, .

&Lt; Control of driving number reduction >

Hereinafter, the main turbocharger 20 and the auxiliary turbocharger 30 are operated, and the auxiliary turbocharger 30 is stopped while the main turbocharger 20 is operated to reduce the number of operations of the supercharger. Explain. 3 is a flow chart showing a method of controlling the number of driving operations. The calculation and control described below are performed by the control device 60. [ 4 is a time chart showing the opening degrees of the auxiliary turbine inlet valve 41, the auxiliary compressor outlet valve 42 and the windshield valve 43. As shown in FIG. On the other hand, FIG. 4 conceptually shows that it does not necessarily coincide with the actual value (the same applies to other time charts and graphs described below).

First, when the process is started, the control device 60 simultaneously closes the auxiliary turbine inlet valve 41 and the auxiliary compressor outlet valve 42 (step S1). Accordingly, the exhaust gas discharged from the engine body 10 is not supplied to the auxiliary turbine 32, and the number of revolutions of the auxiliary turbocharger 30 gradually decreases. On the other hand, as shown in Fig. 4, it takes some time for these valves to be fully closed at full opening. Therefore, since it takes some time until the auxiliary turbocharger 30 is stopped after the auxiliary turbine inlet valve 41 is started to be closed, the auxiliary compressor outlet valve 42 is started to be slightly delayed from the auxiliary turbine inlet valve 41 It is possible to prevent the outside air that has been boosted by the main compressor 23 from flowing backward to the auxiliary compressor 33. [

Subsequently, the control device 60 reads the signals transmitted from the auxiliary turret rotating machine 36 and the auxiliary compressor outlet pressure gauge 37 and acquires the auxiliary turbocharger speed and the auxiliary compressor outlet pressure according to the signals (step S2).

Subsequently, the control device 60 determines the stop-time reference pressure in accordance with the auxiliary turbocharger revolution number acquired in step S2 (step S3). 5 is a diagram showing the relationship between the flow rate of the auxiliary compressor and the pressure of the auxiliary compressor at each rotational speed of the auxiliary turbocharger 30, that is, a diagram showing a pressure curve at each rotational speed (compressor map). The bold lines in the drawing indicate lines (surge lines) connecting points where surges occur at each revolution. The dashed line in the drawing is a reference pressure line for stopping at the time of stoppage that is preset to have a predetermined interval (surge margin) in the surge line. The above-mentioned "stop-time reference pressure" is the pressure at which the pressure curve intersects the reference pressure line at the stop. The control device (60) stores data of the reference pressure at the time of stoppage for each rotation speed of the auxiliary turbocharger (30). Therefore, the reference pressure at the time of stop can be determined in accordance with the number of revolutions of the auxiliary turbocharger 30 acquired.

Subsequently, the control device 60 determines whether the auxiliary compressor outlet pressure is greater than the reference pressure at the time of stop (step S4). That is, it is determined whether or not there is a risk of occurrence of surge in the auxiliary compressor 33. [ If it is determined that the auxiliary compressor outlet pressure is equal to or lower than the stop reference pressure (NO in step S4), the process proceeds to step S5. In other words, if it is determined that there is no possibility of surge occurring in the auxiliary compressor 33, the process proceeds to step S5. On the other hand, if it is determined that the auxiliary compressor outlet pressure is greater than the stop reference pressure (YES in step S4), the process proceeds to step S6. In other words, when it is determined that there is a possibility of occurrence of surge in the auxiliary compressor 33, the process proceeds to step S6.

It is determined that there is no possibility of a surge occurring in the auxiliary compressor 33. When the process proceeds to step S5, the control device 60 transmits a control signal to the windshield valve 43 to reduce the opening degree of the windshield valve 43. [ On the other hand, when it is determined that there is a possibility of occurrence of a surge in the auxiliary compressor 33, the control device 60 transmits a control signal to the windshield valve 43 to increase the opening degree of the windshield valve 43 . On the other hand, in the present embodiment, the change amount of the opening degree of the windshield valve 43 is determined according to the difference between the outlet pressure of the auxiliary compressor and the reference pressure at the time of stoppage. That is, the smaller the difference between the outlet pressure of the auxiliary compressor and the reference pressure at the time of stopping, the smaller the increase / decrease amount of the windshield valve 43 is.

Subsequently, after the step S5 or S6, the control device 60 judges whether or not the auxiliary turbocharger 30 has stopped (step S7). That is, it is determined whether or not the auxiliary turbocharger revolution number becomes zero (0). If it is determined that the auxiliary turbocharger 30 has stopped (YES in step S7), the process is terminated. On the other hand, if it is determined that the auxiliary turbocharger 30 is not stopped (NO in step S7), the process returns to step S2 and steps S2 to S7 are repeated.

4 shows the opening of the wind-guard valve 43 of the present embodiment, and the broken line indicates the opening of the auxiliary turbine inlet valve 41, And the opening of the windshield valve 43 when the windshield valve 43 starts to open (in the case of early opening) at the same time as the start of closing the auxiliary compressor outlet valve 42. [ On the other hand, in the above-described Patent Documents 1 to 3, the windshield valve 43 is opened at a timing earlier than that indicated by the broken line. As shown in this figure, in the case of this embodiment, since the windshield valve 43 is not opened when there is no possibility of a surge occurring in the sub-compressor 33, the opening timing of the windshield valve 43 is set to the early opening Can be delayed. In the present embodiment, the opening degree of the windshield valve 43 is not increased at a constant rate, but the opening degree may be reduced when the possibility of occurrence of surge is small. As a result, the opening of the windshield valve 43 can be reduced as much as possible within the range where no surge occurs.

6 is a diagram showing the temporal change of the auxiliary compressor outlet pressure and the scavenging pressure. 6, the solid line indicates the case of this embodiment, and the broken line indicates the case of early opening (see the bottom view of Fig. 4). 6, the start of opening of the windshield valve 43 is delayed in comparison with the case of early opening in the case of the present embodiment, It can be seen that the start of decreasing the outlet pressure is also delayed.

Subsequently, paying attention to the diagram showing the temporal change of the scavenging pressure in FIG. 6 (the lower diagram in FIG. 6), the decline of the scavenging pressure is smaller in this embodiment as compared with the case of early opening. This is because, in the case of the present embodiment, even after the auxiliary compressor outlet valve 42 starts to be closed, the outside air raised by the auxiliary compressor 33 can be used as a scavenging gas.

As described above, according to the present embodiment, when the number of the supercharger is reduced, compared with the case where the wind turbine 43 is started to be opened early considering the occurrence of surge, It is possible to suppress the decrease of the scavenging pressure even after the stop. Therefore, according to the present embodiment, the engine main body 10 can be operated more efficiently than in the conventional case.

&Lt; Control of driving number increase >

Then, the main turbocharger 20 is operated and the main turbocharger 20 is operated while the auxiliary turbocharger 30 is stopped. In this case, the auxiliary turbocharger 30 is operated to increase the number of the superchargers. Control) will be described. 7 is a flowchart showing a method of controlling the number of driving increases. The calculation and control described below are performed by the control device 60. [ 8 is a time chart showing the opening degrees of the auxiliary turbine inlet valve 41, the auxiliary compressor outlet valve 42, and the windshield valve 43. FIG.

First, when the process is started, the control device 60 opens the auxiliary turbine inlet valve 41 (step S11). The exhaust gas is supplied to the auxiliary turbine 32 and the auxiliary turbocharger 30 starts to operate. On the other hand, the auxiliary compressor outlet valve 42 is not opened simultaneously with the auxiliary turbine inlet valve 41. This is because, when the auxiliary compressor outlet valve 42 is opened while the number of revolutions of the auxiliary turbocharger 30 is low and the pressure of the auxiliary compressor is low, the outside air boosted by the main compressor 23 flows back to the auxiliary compressor 33.

Subsequently, the control device 60 reads the signals transmitted from the engine rotation system 11, the fuel supply device 12, the auxiliary turret rotation system 36, and the auxiliary compressor output pressure gauge 37, Rotation speed, and fuel injection amount), the auxiliary turbocharger revolution speed, and the auxiliary compressor outlet pressure (step S12).

Subsequently, the control device 60 determines the switching rotation speed (step S13). The term "switching rotation speed" as used herein refers to the auxiliary turbocharger rotation speed when the auxiliary compressor outlet valve 42 starts to be opened. The switching rotation speed is determined according to the engine load. More specifically, the control device 60 stores map data corresponding to the graph shown in Fig. 9, and determines the switching rotation speed in accordance with the acquired engine load. As shown in Fig. 9, as the engine load increases, the switching rotation speed increases.

Subsequently, the control device 60 determines whether or not the auxiliary turbocharger revolution acquired in step S12 is equal to or larger than the conversion revolution number determined in step S13 (step S14). When it is judged that the number of revolutions of the auxiliary turbocharger is equal to or larger than the switching revolving speed (YES in step S14), the opening of the auxiliary compressor outlet valve 42 is started (step S15), and then the process goes to step S16. On the other hand, when it is determined that the number of rotations of the auxiliary turbocharger is smaller than the number of switching rotations (NO in step S14), the process goes to step S16 without going through step S15.

Subsequently, the control device 60 determines the reference pressure during operation according to the auxiliary turbocharger revolution number acquired in step S12 (step S16). The reference pressure at the time of operation is a pressure having a predetermined amount of surge margin in the same manner as the reference pressure at the time of stop (see step S3 in Fig. 3). The control device 60 stores the data of the reference pressure during operation for each auxiliary turbocharger revolution speed. Therefore, the reference pressure at the time of operation can be determined according to the acquired number of revolutions of the auxiliary turbocharger. The reference pressure during operation and the reference pressure during stop may be set to the same value at each auxiliary turbocharger rotation speed.

Subsequently, the control device 60 determines whether or not the auxiliary compressor outlet pressure is greater than the reference pressure during operation (step S17). That is, it is determined whether or not there is a risk of occurrence of surge in the auxiliary compressor 33. [ If it is determined that the auxiliary compressor outlet pressure is equal to or lower than the reference pressure during operation (NO in step S17), the process proceeds to step S18. In other words, if it is determined that there is no possibility of surge occurring in the auxiliary compressor 33, the process proceeds to step S18. On the other hand, when it is determined that the outlet pressure of the auxiliary compressor is larger than the reference pressure during operation (YES in step S17), the process proceeds to step S19. In other words, when it is determined that there is a possibility of occurrence of surge in the auxiliary compressor 33, the process proceeds to step S19.

If it is determined that there is no possibility of a surge occurring in the auxiliary compressor 33, the control device 60 transmits a control signal to the windshield valve 43 to reduce the opening degree of the windshield valve 43 in step S18. On the other hand, if it is determined that there is a possibility that a surge may occur in the auxiliary compressor 33, the control device 60 transmits a control signal to the windshield valve 43 to increase the opening degree of the windshield valve 43 in step S19. On the other hand, when the opening degree of the windshield valve 43 is increased, the opening / closing amount of the windshield valve 43 is decreased as the difference between the outlet pressure of the auxiliary compressor and the reference pressure during operation becomes smaller.

Subsequently, after step S18 or S19, the control device 60 determines whether the auxiliary compressor outlet valve 42 is fully opened (step S20). On the other hand, whether or not the auxiliary compressor outlet valve 42 is fully opened can be judged by the limit switch for confirming the fully closed / fully opened state of the auxiliary compressor outlet valve 42 or the time after the opening of the auxiliary compressor outlet valve 42 is started. When it is determined that the auxiliary compressor outlet valve 42 is fully opened (YES in step S20), the process is terminated. On the other hand, if it is determined that the auxiliary compressor outlet valve 42 is not completely opened (NO in step S20), the process returns to step S12 and steps S12 to S20 are repeated.

As described above, according to the driving-logarithm increase control of the present embodiment, the opening degree of the wind-guard valve 43 (including the fully closed state) is controlled to be as small as possible within a range where no surge occurs. Therefore, the outside air raised by the auxiliary compressor 33 is suppressed from being discharged to the outside, and is supplied to the engine main body 10 as a purge gas as soon as the auxiliarycompressor outlet valve 42 starts to be opened. Therefore, the desired pressure can be increased, and the engine body 10 can be efficiently operated.

In addition, in the operation number increase control of this embodiment, the timing of opening the auxiliary compressor outlet valve 42 is determined according to the engine load and the number of revolutions of the auxiliary turbocharger. However, the timing of opening the auxiliary compressor outlet valve 42 is not limited thereto. For example, as shown in FIG. 10, a differential pressure gauge 38 for measuring the differential pressure of the auxiliary compressor outlet valve 42 may be provided to determine timing for opening the auxiliary compressor outlet valve 42 in accordance with the differential pressure between the differential pressure and the differential pressure . Concretely, the auxiliary compressor outlet valve 42 may be opened when the pressure on the upstream side of the auxiliary compressor outlet valve 42 becomes higher than the pressure on the downstream side.

10, a scavenging pressure gauge 39 for measuring scavenging pressure is provided between the air cooler 50 and the engine main body 10 so that the pressure difference between the outlet pressure of the subcompressor and the scavenging pressure becomes a predetermined threshold value The auxiliary compressor outlet valve 42 may be opened. As the auxiliary compressor outlet valve 42, the outside air that is boosted by the auxiliary compressor 33 flows to the engine main body 10, but the outside air that is boosted by the main compressor 23 is supplied to the auxiliary compressor 33 as a check valve May be adopted.

(Second Embodiment)

Next, the second embodiment will be described. In this embodiment, the driving-logarithm increase control method is different from that of the first embodiment. Hereinafter, the driving number increase control of the present embodiment will be described.

Fig. 11 is a flowchart showing a driving number increase control method of the present embodiment. 12 is a time chart showing the opening degrees of the auxiliary turbine inlet valve 41, the auxiliary compressor outlet valve 42 and the windshield valve 43, and the number of revolutions of the auxiliary turbocharger 30. FIG.

11, the control device 60 starts opening the windshield valve 43 so that the opening degree of the windshield valve 43 becomes the predetermined opening degree (step S21), and after a predetermined time, the auxiliary turbine inlet valve 41) (step S22). As the auxiliary turbine inlet valve 41 starts to open, the auxiliary turbocharger 30 starts to operate (see FIG. 12).

Subsequently, the control device 60 reads signals transmitted from the engine rotation system 11, the fuel supply device 12, and the auxiliary turret rotation system 36 and reads the engine load (estimated from the engine speed and the fuel injection amount) And the number of revolutions of the auxiliary turbocharger (step S23).

Subsequently, the control device 60 determines the first switching operating point (secondary compressor flow rate and secondary compressor outlet pressure) (step S24). The "first switching operating point" is an operating point of the auxiliary compressor 33 having a predetermined surge margin, and is a time point at which the windshield valve 43 is started to be closed. The operation point of the auxiliary compressor 33 varies greatly depending on the opening and closing of the windshield valve 43 and therefore the operation curve of the auxiliary compressor 33 (locus of the operating point) is also different if the timing to close the windshield valve 43 is different . In the present embodiment, when the windshield valve 43 is started to be closed when the auxiliary compressor 33 reaches a certain operating point, the operation is started from just before starting to close the windshield valve 43 until just before starting opening the auxiliary compressor outlet valve 42 That is, an operating point that satisfies a condition that a surge does not occur, that is, an operating curve therebetween does not reach the surge region, is set as the first switching operating point. However, the first switching operating point varies depending on the engine load. Further, the auxiliary compressor outlet pressure and the auxiliary compressor flow rate at the first switching operating point are set as the first switching pressure and the first switching flow rate, respectively (see Fig. 15). The control device 60 stores map data corresponding to the graph of the first switching pressure shown in Fig. 13, and determines the first switching pressure in accordance with the map data and the engine load acquired in step S23. Similarly, the control device 60 stores map data corresponding to the graph of the first switching flow rate shown in Fig. 14, and determines the first switching flow rate in accordance with the map data and the engine load acquired in step S23 . On the other hand, as shown in Figs. 13 and 14, the larger the engine load, the larger the first switching pressure and the first switching flow rate.

Subsequently, the control device 60 determines the first switching rotation speed (step S25). In the present embodiment, the auxiliary turbocharger rotational speed of the pressure curve passing through the first switching operating point of the auxiliary compressor 33 is defined as the first switching rotational speed. For example, as shown in FIG. 15, when the pressure curve of the X% revolution passes through the point A which is the first switching operating point, the first switching revolution number is X% revolution number. On the other hand, depending on the operation state of the engine, the operating point of the auxiliary compressor 33 may differ from the first switching operating point when the auxiliary turbocharger rotational speed reaches the first switching rotational speed. However, since the first switching operating point has a predetermined surge margin, even if the actual operating point slightly deviates from the first switching operating point, it is possible to start the opening of the auxiliary compressor outlet valve 42 immediately before starting to close the windshield valve 43 The surge of the auxiliary compressor 33 can be prevented.

Subsequently, the control device 60 determines whether or not the auxiliary turbocharger revolution number is equal to or larger than the first switching revolution number (step S26). When it is judged that the auxiliary turbocharger revolution number is equal to or larger than the first switching revolution number (YES in step S26), the closing of the windshield valve 43 is started (step S27; see Fig. 12). On the other hand, when it is determined that the auxiliary turbocharger rotation speed is smaller than the first switching rotation speed (NO in step S26), the process returns to step S23 to repeat steps S23 to S26.

After the start of the closing of the windshield valve 43 via step S27, the control device 60 reads the signals transmitted from the engine rotation system 11, the fuel supply system 12 and the auxiliary turret rotation system 36 again, The engine load and the auxiliary turbocharger revolution speed are acquired (step S28).

Subsequently, the control device 60 determines a second switching operating point (step S29). The "second switching operating point" is an operating point of the auxiliary compressor 33 having a predetermined surge margin, and is a time point at which the auxiliary compressor outlet valve 42 starts to be opened. The second switching operating point is determined to be the same as the first switching operating point. That is, when the auxiliary compressor 33 starts to open the auxiliary compressor outlet valve 42 when the operating point of the auxiliary compressor 33 reaches the operating point, the auxiliary compressor outlet valve 42 starts to be opened An operating point that does not cause a surge, that is, an operating point that satisfies the condition that the operating curve does not reach the surge region is set as the second switching operating point. The second switching operation point also changes in accordance with the engine load similarly to the first switching operation point. Further, the auxiliary compressor outlet pressure and the auxiliary compressor flow rate at the second switching operating point are set as the second switching pressure and the second switching flow rate, respectively (see Fig. 15). The control device 60 determines the second switching pressure and the second switching flow rate according to the map data and the engine load corresponding to the graph of the second switching pressure and the second switching flow rate shown in Figs. When the engine load is the same, the second switching pressure and the second switching flow rate are determined to be higher than the first switching pressure and the first switching flow rate, respectively.

Subsequently, the control device 60 determines the second switching rotation speed (step S30). As in the case of the first switching rotation speed, the auxiliary turbocharger rotation speed of the pressure curve passing through the second switching operating point of the auxiliary compressor 33 is defined as the second switching rotation speed. For example, as shown in FIG. 15, when the pressure curve of the Y% rotation number passes through the point B which is the second switching operating point, the second switching rotation number is set as the Y% rotation number. On the other hand, since the second switching pressure and the second switching flow rate are larger than the first switching pressure and the first switching flow rate, respectively, the second switching rotation speed becomes higher than the first switching rotation speed. The operating point of the auxiliary compressor may differ from the second switching operating point when the auxiliary turbocharger rotation speed reaches the second switching rotation speed depending on the operation state of the engine or the like. However, since the second switching operating point has a predetermined surge margin, even if the actual operating point slightly deviates from the second switching operating point, the auxiliary compressor (the first switching operating point, the second switching operating point, 33 can be prevented.

Subsequently, the control device 60 determines whether the auxiliary turbocharger revolution number is equal to or larger than the second switching revolution number (step S31). If it is determined that the number of revolutions of the auxiliary turbocharger is equal to or larger than the second switching rotational speed (YES in step S31), the opening of the auxiliary compressor outlet valve 42 is started (step S32; see FIG. 12). On the other hand, if it is determined that the auxiliary turbocharger rotation speed is smaller than the second switching rotation speed (NO in step S31), the process returns to step S28 and steps S28 to S31 are repeated.

The drive number increase control of the present embodiment is as described above. As shown in Fig. 12, after the opening of the auxiliary turbine inlet valve 41 is started in a state in which the wind turbine 43 is opened at a predetermined opening degree, the operation of the wind turbine 43 Closure is started, and then opening of the auxiliary compressor outlet valve 42 is started. That is, since the opening of the auxiliary compressor outlet valve 42 is started in a state where the windshield valve 43 is closed to some extent, it is possible to prevent the outside air that has been boosted by the auxiliary compressor 33 from being discharged to the outside through the windshield valve 43 . In addition, since the outside air is sufficiently boosted by the auxiliary compressor 33, it is possible to prevent the outside air that has been boosted by the main compressor 23 from flowing backward to the auxiliary compressor 33. [ Therefore, the decrease in efficiency of the engine body 10 can be suppressed. In addition, since the opening / closing of the auxiliary compressor outlet valve 42 and the windshield valve 43 is controlled in accordance with the auxiliary turbocharger revolution speed, the operation of the auxiliary-compressor outlet pressure can be omitted in this embodiment. Therefore, for example, in the case of not using the auxiliary compressor outlet pressure in the driving number reduction control as well as the driving number increase control, such as performing the driving number reduction control according to the time schedule, the auxiliary compressor outlet pressure gauge 37 Can be omitted.

Although it has been described above that the wind turbine 43 is closed when the number of rotations of the auxiliary turbocharger is determined to be equal to or larger than the first switching rotation speed (steps S26 and S27) That is, the rate of decrease (rate of change) of the opening degree of the windshield valve 43 may not be constant. For example, the greater the difference between the number of rotations of the auxiliary turbocharger and the first switching rotation speed, the larger the number of rotations for closing the windshield valve 43, that is, the reduction amount of the opening degree of the windshield valve 43 may be increased. According to such a configuration, when the possibility of occurrence of surge of the auxiliary compressor 33 is low, the windshield valve 43 can be closed more quickly, so that the efficiency reduction of the engine body 10 can be further suppressed.

(Third Embodiment)

Next, the third embodiment will be described. This embodiment adds a predetermined step to the drive number increase control in the second embodiment. Hereinafter, the description will be focused on a portion different from the second embodiment of the present embodiment.

16 is a schematic configuration diagram of the entire engine system 200 according to the present embodiment. 16, in the engine system 200 according to the present embodiment, the main scavenging pipe 25 is provided with the main compressor outlet pressure gauge 40, but in addition to the first and second embodiments shown in Fig. 1, And has the same configuration as the engine system 100 according to the embodiment. The main compressor outlet pressure gauge 40 is at the outlet side of the main compressor 23 and is located upstream of the air cooler 50. The main compressor outlet pressure gauge 40 is electrically connected to the control device 60 and the control device 60 acquires the main compressor outlet pressure in accordance with the signal transmitted from the main compressor outlet pressure gauge 40.

Fig. 17 is a flowchart showing a method for controlling the increase in the number of drives in the present embodiment, and corresponds to Fig. 11 of the second embodiment. As can be seen from comparison between FIG. 17 and FIG. 11, the driving number increase control of the present embodiment adds steps S41 and S42 to the driving number increase control of the second embodiment. In the second embodiment, when the controller 60 determines in step S29 that the number of rotations of the auxiliary turbocharger is equal to or larger than the second switching rotational speed, the opening of the auxiliary compressor outlet valve 42 is started. However, in this embodiment, If it is determined that the number of revolutions of the auxiliary turbocharger is equal to or larger than the second switching rotation speed, the process proceeds to step S41 without immediately starting opening of the auxiliary compressor outlet valve 42.

In step S41, the control device 60 reads the signal transmitted from the main compressor outlet pressure gauge 40 and acquires the main compressor outlet pressure in accordance with the signal.

Subsequently, the control device 60 determines whether or not the main compressor outlet pressure acquired at step S41 is equal to or lower than the second switching pressure used at the time of determining the second switching operating point at step S29 (step S42). When the main compressor outlet pressure is equal to or lower than the second switching pressure (YES in step S42), the opening of the auxiliary compressor outlet valve 42 is started (step S32), and then the process is terminated. On the other hand, if it is determined that the main compressor outlet pressure is larger than the second switching pressure (NO in step S42), the process returns to step S28 to repeat steps S28 to S31, S41, and S42.

As described above, in this embodiment, the auxiliary compressor outlet valve 42 is opened only when the auxiliary turbocharger rotational speed is not less than the second switching rotational speed, and when the main compressor outlet pressure is equal to or lower than the second switching pressure.

Here, even when the ship sails at a constant speed, the engine load may fluctuate greatly depending on the situation of the sea. While the main compressor outlet pressure is controlled to be lower when the engine load is lowered, it takes some time until the engine load is lowered and then the main compressor outlet pressure is lowered. Therefore, when the engine load is lowered and the operation number increase control is performed, there is a possibility that the outdoor air boosted by the main compressor 23 flows back to the side of the auxiliary compressor 33 because the outlet pressure of the main compressor is still high.

On the other hand, in this embodiment, the opening of the auxiliary compressor outlet valve 42 is started only when the main compressor outlet pressure is equal to or lower than the second switching pressure. The auxiliary compressor outlet pressure is the second switching pressure when the opening of the auxiliary compressor outlet valve 42 is started since the original auxiliary compressor outlet pressure begins to open the auxiliary compressor outlet valve 42 when the secondary switching pressure becomes the second switching pressure. Thus, when the main compressor outlet pressure is below the second switching pressure as in the present embodiment, when the opening of the auxiliary compressor outlet valve 42 is started, the main compressor outlet pressure becomes smaller than the auxiliary compressor outlet pressure. Therefore, according to the present embodiment, even when the engine load fluctuates, outside air that has been boosted by the main compressor 23 does not flow back to the side of the auxiliary compressor 33. [

In this embodiment, the outlet pressure of the main compressor is obtained by using the outlet pressure gauge 40 of the main compressor. However, the outlet pressure of the main compressor may be obtained at the downstream side of the air cooler 50 of the main spout pipe 25 , And the main compressor outlet pressure may be acquired (estimated) in accordance with the scaling pressure measured by the scavenging pressure gauge. This also applies to the case of the fourth embodiment described later.

(Fourth Embodiment)

Next, the fourth embodiment will be described. The present embodiment differs from the second embodiment in the method for determining the first switching rotation speed and the second switching rotation speed. Hereinafter, a method for determining the first switching rotation speed and the second switching rotation speed in this embodiment will be mainly described.

The overall configuration of the engine system according to the present embodiment is basically the same as the engine system 200 of the third embodiment shown in Fig. That is, in the engine system according to the present embodiment, the main scavenging pipe 25 is provided with a main compressor outlet pressure gauge 40.

Fig. 18 is a flowchart showing the drive number increase control method of this embodiment, which corresponds to Fig. 11 of the second embodiment. As can be seen from comparison between FIG. 18 and FIG. 11, the drive number increase control of the present embodiment changes the drive number increase control steps S23, S28, and S29 of the second embodiment to the steps S51, S53, and S54, It is added.

In the second embodiment, after the step S22, the engine load and the auxiliary turbocharger rotational speed are obtained (see step S23 in Fig. 11). In this embodiment, the main compressor outlet pressure gauge 40 and the auxiliary turbocharger rotational engine 36 Reads the signal to be transmitted, and acquires the "main compressor outlet pressure" and the auxiliary turbocharger speed in accordance with this signal (step S51). Thereafter, the control device 60 estimates the engine load in accordance with the main compressor outlet pressure acquired in step S51 (step S52). More specifically, the control device 60 stores map data corresponding to the graph shown in Fig. 19, and estimates the engine load in accordance with the map data and the obtained compressor outlet pressure. On the other hand, as shown in Fig. 19, the larger the compressor outlet pressure, the larger the estimated engine load.

Thereafter, as in the second embodiment, the first switching operating point is determined in accordance with the estimated engine load (step S24), and the first switching rotation speed is determined (step S24). On the other hand, there is a slight error between the engine load estimated in step S52 and the actual engine load. However, as mentioned above, since the first switching operating point has a predetermined surge margin, It is possible to prevent surge of the auxiliary compressor 33 from immediately before the start of closing the windshield valve 43 to just before starting opening of the auxiliary compressor outlet valve 42. [

In the present embodiment, after the step S27, the main compressor outlet pressure and the auxiliary turbocharger rotational speed are obtained as in the step S51 (step S53). Thereafter, the control device 60 determines a second switching operating point (step S54). More specifically, the control device 60 sets the same value as the main compressor outlet pressure acquired in step S53 as the second switching pressure. A value obtained by adding a predetermined flow rate (margin flow rate) to the flow rate of the sub compressor 33 in which a surge occurs at this second switching pressure is set as the second switching flow rate. Further, the operating point at which the auxiliary compressor outlet pressure is the second switching pressure and the auxiliary compressor flow rate is the second switching flow rate is the second switching operating point. 20, a point C which is a point (a standing point) of the second switching pressure (main compressor outlet pressure) in the surge line is taken, and the point C is shifted toward the increase of the auxiliary compressor flow rate by a predetermined margin flow rate And a point D is set as a second switching operating point.

Subsequently, in step S30 of FIG. 18, the auxiliary turbocharger rotation speed of the pressure curve passing through the second switching operating point of the auxiliary compressor 33 is defined as the second switching rotation speed. For example, as shown in Fig. 20, when the pressure curve of the Z% rotation speed passes through the point D which is the second switching operating point, the second switching rotation speed is defined as Z% rotation speed. The processing after determining the second switching rotation speed (steps S31 and S32) is the same as that in the second embodiment.

On the other hand, the value of the margin flow rate is not particularly limited. The flow rate of the margins may be constant or may be varied as the outlet pressure of the main compressor is increased. In the above, the point D shifted to the increase of the auxiliary compressor flow rate by the predetermined margin flow rate at the point C, which is the point in the above, is set as the second switching operating point, but the direction of the shift is not limited to the increasing direction of the auxiliary compressor flow rate. For example, the second switching operating point may be a point shifted from the standing position (point C) toward the increase of the auxiliary compressor flow rate by a predetermined margin flow rate and shifted toward the decrease of the auxiliary compressor pressure by the predetermined margin pressure.

As described above, in this embodiment, the first switching rotation speed and the second switching rotation speed are determined in accordance with the main compressor outlet pressure instead of the engine load, and when the auxiliary turbocharger rotation speed is equal to or greater than the first switching rotation speed, And starts opening the auxiliary compressor outlet valve 42 when the second switching rotation speed is equal to or higher than the second switching rotation speed. As described above, the timing of closing the windshield valve 43 and the timing of opening the auxiliary compressor outlet valve 42 are not affected by the engine load, and therefore, it is effective in the case of performing the increase control of the movable number in a situation where the engine load fluctuates. In the case where the engine load is not used not only in the number-of-drives increase control but also in the number-of-drives reduction control, such as by performing the number-of-drives reduction control according to the first embodiment, And the connection of the fuel supply device 12 can be omitted.

The first to fourth embodiments have been described above. Although the engine systems 100 and 200 have one main supercharger 20 and one auxiliary turbocharger 30 in the above description, the engine systems 100 and 200 may have a plurality of main superchargers 20 And the auxiliary turbochargers 30 may be provided in plural. For example, in the first embodiment, the engine system 100 may include one main turbocharger 20 and two auxiliary turbochargers 30 as shown in Fig.

According to the engine system of the present invention, it is possible to prevent the efficiency of the engine body from decreasing when changing the number of superchargers to be driven while preventing occurrence of surge in the supercharger. Therefore, it is advantageous in the technical field of the engine system for changing the number of superchargers to be driven depending on the driving situation.

10: engine body
20: main supercharger
22: Main turbine
23: Main compressor
30: auxiliary supercharger
32: Auxiliary turbine
33: Auxiliary compressor
41: auxiliary turbine inlet valve
42: Auxiliary compressor outlet valve
43: windproof valve
44: wind tunnel piping
60: Control device
100, 200: engine system

Claims (12)

An engine body,
One or more main turbochargers having a main turbine and a main compressor,
One or more auxiliary turbochargers arranged in parallel with the main turbocharger with respect to the engine main body and having an auxiliary turbine and an auxiliary compressor,
An auxiliary turbine inlet valve provided on the inlet side of the auxiliary turbine,
An auxiliary compressor outlet valve provided on an outlet side of the auxiliary compressor,
A ventilation pipe for guiding the outside air raised in the auxiliary compressor from the upstream side of the auxiliary compressor outlet valve to the outside,
A wind-blowing valve installed in the wind-up pipe,
And a control device,
The control device includes:
When the auxiliary turbocharger inlet valve and the auxiliary compressor outlet valve are closed while the main turbocharger and the auxiliary turbocharger are operated, the auxiliary turbocharger is stopped to reduce the number of the supercharger,
Determining a stopping reference pressure having a predetermined surge margin based on the auxiliary turbocharger revolution speed and increasing the opening degree of the windshield valve when the auxiliary compressor outlet pressure is higher than the stopping reference pressure, And when the engine is stopped, the opening degree of the windshield valve is decreased when the reference pressure is lower than the reference pressure.
The method according to claim 1,
Wherein the control device is configured to reduce an increase in the opening degree of the windshield valve as the difference between the outlet pressure of the auxiliary compressor and the reference pressure at the time of stopping increases as the opening degree of the windshield valve is increased.
An engine body,
One or more main turbochargers having a main turbine and a main compressor,
One or more auxiliary turbochargers arranged in parallel with the main turbocharger with respect to the engine main body and having an auxiliary turbine and an auxiliary compressor,
An auxiliary turbine inlet valve provided on the inlet side of the auxiliary turbine,
An auxiliary compressor outlet valve provided on an outlet side of the auxiliary compressor,
A ventilation pipe for guiding the outside air raised in the auxiliary compressor from the upstream side of the auxiliary compressor outlet valve to the outside,
A wind-blowing valve installed in the wind-up pipe,
And a control device,
The control device includes:
When the main turbocharger is operated and the auxiliary turbocharger is stopped, the auxiliary turbocharger inlet valve and the auxiliary compressor outlet valve are opened while the main turbocharger is operated to increase the number of the supercharger by operating the auxiliary turbocharger,
Determining a reference pressure during operation having a predetermined surge margin based on the number of revolutions of the auxiliary turbocharger and increasing the opening degree of the windshield valve when the outlet pressure of the auxiliary compressor is higher than the reference pressure during the operation, And to reduce the opening degree of the windshield valve when it is lower than a reference pressure during operation.
The method of claim 3,
Wherein the control device is configured to reduce an increase in the opening degree of the windshield valve as the difference between the outlet pressure of the auxiliary compressor and the reference pressure during operation increases as the opening degree of the windshield valve increases.
The method according to claim 3 or 4,
The control device starts opening the auxiliary compressor outlet valve when the auxiliary turbocharger rotational speed becomes equal to or greater than a predetermined switching rotational speed after starting the opening of the auxiliary turbine inlet valve when the number of operations of the supercharger is increased, Is configured to be determined according to an engine load.
An engine body,
One or more main turbochargers having a main turbine and a main compressor,
One or more auxiliary turbochargers arranged in parallel with the main turbocharger with respect to the engine main body and having an auxiliary turbine and an auxiliary compressor,
An auxiliary turbine inlet valve provided on the inlet side of the auxiliary turbine,
An auxiliary compressor outlet valve provided on an outlet side of the auxiliary compressor,
A ventilation pipe for guiding the outside air raised in the auxiliary compressor from the upstream side of the auxiliary compressor outlet valve to the outside,
A wind-blowing valve installed in the wind-up pipe,
And a control device,
The control device includes:
When the main turbocharger is operated and the auxiliary turbocharger is stopped, the auxiliary turbocharger inlet valve and the auxiliary compressor outlet valve are opened while the main turbocharger is operated to increase the number of the supercharger by operating the auxiliary turbocharger,
After the start of opening of the auxiliary turbine inlet valve in a state where the wind turbine valve is opened at a predetermined opening degree, when the auxiliary turbocharger rotational speed becomes the predetermined first switching rotational speed or more, closing of the wind turbine valve is started, Wherein the opening of the auxiliary compressor outlet valve is started when the number of the auxiliary compressors is equal to or larger than a second switching rotational speed that is larger than the first switching rotational speed.
The method according to claim 6,
Wherein the control device determines a first switching operating point of the auxiliary compressor having a predetermined surge margin based on the engine load and sets the auxiliary turbocharger rotation speed of the pressure curve passing through the first switching operating point to the first switching rotation And the number of the engine cylinders.
8. The method according to claim 6 or 7,
Wherein the control device determines a second switching operating point of the subcompressor having a predetermined surge margin based on the engine load and sets the auxiliary turbocharger rotation speed of the pressure curve passing through the second switching operating point to the second switching rotation And the number of the engine cylinders.
9. The method of claim 8,
Wherein the control device acquires the main compressor outlet pressure when increasing the number of superchargers to be driven, and when the auxiliary turbocharger rotation speed is equal to or higher than the second switching rotation speed and the acquired main compressor outlet pressure is equal to or higher than the auxiliary compressor outlet pressure And to start opening the auxiliary compressor outlet valve when the auxiliary compressor outlet valve is smaller than the predetermined value.
The method according to claim 6,
The control device obtains the main compressor outlet pressure, sets the same value as the obtained main compressor outlet pressure as the second switching pressure, and sets a value obtained by adding the predetermined flow rate to the auxiliary compressor flow rate generated by the surge at the second switching pressure 2 as the second switching operating point and the second switching operating point as the second switching operating point as the second switching operating point and the auxiliary turbocharger rotational speed of the pressure curve passing through the second switching operating point to the second switching And the engine speed is set to the engine speed.
11. The method of claim 10,
The control device estimates the engine load based on the acquired main compressor outlet pressure, determines a first switching operating point of the auxiliary compressor having a predetermined surge margin based on the estimated engine load, And the auxiliary turbocharger rotation speed of the pressure curve passing through the point is set to the first switching rotation speed.
12. The method according to one of claims 6 to 11,
Wherein the control device is configured to reduce the amount of opening of the windshield valve as the difference between the rotation speed of the auxiliary turbocharger and the first switching rotation speed decreases as the windshield valve is closed.

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