KR101861754B1 - Engine system and ship - Google Patents

Abstract

The engine system 100 reduces the opening area of the variable nozzle 32 when the amount of the exhaust gas discharged from the engine body 10 is reduced so that the amount of exhaust gas discharged from the engine body 10 When the amount of the exhaust gas discharged from the engine body 10 is increased and the opening area of the variable nozzle 32 is increased, the amount of exhaust gas supplied to the engine body 10 is increased, The ratio of the amount of exhaust gas to be supplied to the supercharger 20 to the amount of exhaust gas to be supplied to the supercharger 20 is reduced.

Description

Engine system and ship {ENGINE SYSTEM AND SHIP}

The present invention relates to an engine system for efficiently recovering waste heat energy.

In an engine system (for example, see Patent Document 1) having both a supercharger and a power turbine driven by the energy of exhaust gas, a necessary amount of exhaust gas is preferentially supplied to the turbocharger and the remaining exhaust gas is supplied to the power turbine Control is performed.

Further, in an engine system having both a supercharger and a power turbine, there is a case where an open / close valve is provided in a flow path of exhaust gas to be supplied to the power turbine side and the exhaust gas is controlled to flow to the power turbine side by closing the open / have.

Japanese Patent Application Laid-Open No. 10-169455

Control is performed such that the exhaust gas is preferentially supplied to the supercharger side. In the engine system, the power turbine is most influenced by the fluctuation of the amount of the exhaust gas discharged from the engine body, and the setting of the power turbine becomes a problem. For example, it is reasonable that the power turbine is set to be highly efficient at the time of normal operation of the engine main body. However, in this case, when exhaust gas is supplied more than in the normal operation, . It can not be said that this operation can sufficiently recover the waste heat energy. Naturally, the engine system is required to simplify the system.

Also, with respect to the control for preventing exhaust gas from flowing to the power turbine side, the power turbine is driven by the engine body when the power turbine is connected to the engine main body, even if the open / close valve is closed so that the exhaust gas does not flow into the power turbine . At this time, the power turbine operates as a blower and tries to transfer the gas, but the gas does not flow because the opening / closing valve is closed. Therefore, a large force is required to drive the power turbine, which results in a large load on the engine body.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an engine system capable of efficiently recovering waste heat energy and simplifying the system.

Further, the present invention aims to suppress an excessive load on the engine body when the power turbine is not driven by the exhaust gas.

An engine system according to an embodiment of the present invention includes an engine body, a supercharger driven by exhaust gas discharged from the engine body, a power turbine driven by exhaust gas discharged from the engine body, And a power turbine inlet pipe for guiding the exhaust gas discharged from the engine body to the power turbine, wherein the power turbine has a variable nozzle installed at the inlet side, When the amount of exhaust gas discharged from the engine body is reduced, an opening area of the variable nozzle is reduced to increase the ratio of the amount of exhaust gas to be supplied to the supercharger to the amount of exhaust gas discharged from the engine body At the same time, when the amount of exhaust gas discharged from the engine body increases, the opening area of the variable nozzle is increased By Kim is configured to perform the exhaust gas flow rate control to reduce the amount ratio of the exhaust gas supplied to the turbocharger of the amount of exhaust gas discharged from the engine body.

Generally, the variable nozzle is used to improve the efficiency of the turbine (power turbine in the above configuration) according to the amount of exhaust gas by changing the opening area thereof. According to the above configuration, the amount of the exhaust gas to be supplied to the supercharger is adjusted simultaneously with the change in the opening area of the variable nozzle. That is, according to the above configuration, both of the control for efficiently recovering the waste heat energy according to the amount of exhaust gas and the control for supplying exhaust gas suitable for the turbocharger can be performed by the variable nozzles. Therefore, according to the engine system, the waste heat energy can be efficiently recovered and the system can be simplified.

In the engine system, the power turbine inlet pipe may be branched from the supercharger inlet pipe, and may be configured to lead a part of the exhaust gas in the supercharger inlet pipe to the power turbine.

Further, in the engine system, the engine main body has a scavenging tube for receiving fresh air boosted by the turbocharger, and the exhaust gas flow rate control is performed such that when the pressure in the scavenging pipe is smaller than a predetermined lower limit value, And increasing the opening of the variable nozzle when the pressure in the scavenging pipe is greater than a predetermined upper limit value. According to such a configuration, since the variable nozzle is opened and closed in accordance with the pressure in the scavenging pipe, it is possible to supply an appropriate amount of exhaust gas to the supercharger more reliably and easily.

In the engine system, the predetermined lower limit value and the predetermined upper limit value may be set to increase as the load of the engine body increases. According to this configuration, the upper limit value and the lower limit value of the pressure in the scavenge can be appropriately set in accordance with the engine load.

According to another aspect of the present invention, there is provided an engine system including an engine body, a turbocharger driven by exhaust gas discharged from the engine body, and a crankshaft driven by exhaust gas discharged from the engine body, A power turbine inlet pipe for guiding the exhaust gas discharged from the engine body to the power turbine, a power turbine inlet pipe for guiding the exhaust gas discharged from the engine body to the power turbine, An opening / closing valve installed in a turbine inlet pipe for opening and closing according to an operation condition of the engine main body; a supplementary pipe connected to a portion downstream of the opening / closing valve of the power turbine inlet pipe for extracting gas from the power turbine inlet pipe; And an extracting valve provided in the extracting pipe, wherein the engine body is before forward rotation, Closing valve is closed while the engine body is rotating in the reverse direction or when the load of the engine body is lower than the predetermined switching load Closing valve is closed or the introduction opening is smaller than the opening degree of the opening / closing valve under the first condition, and at the same time, the extraction valve is opened.

According to this configuration, even when the power turbine is driven by the crankshaft of the engine body when the power turbine is not driven by the exhaust gas, since the gas passing through the power turbine is added to the additional piping, It is possible to suppress an excessive load from being generated.

Further, in the engine system, the power turbine inlet pipe may be branched from the supercharger inlet pipe, and may be configured to lead a part of the exhaust gas in the supercharger inlet pipe to the power turbine.

In the engine system, even if the upward switching load, which is the switching load when the load of the engine body is rising, is set to be larger than the falling switching load, which is the switching load when the load of the engine body is falling good. According to this configuration, the engine system can be operated after taking into consideration different characteristics when the load of the engine body rises and falls. This makes it possible to operate the engine system more appropriately.

Further, in the engine system, when the load of the engine body rises and becomes larger than the upward switching load, the on-off valve may be opened after the extraction valve is closed. According to such a configuration, since the opening / closing valve is opened after the closing valve is closed instead of opening the opening / closing valve at the same time as the closing valve is closed, there is no case in which a passage with a small resistance is formed even temporarily, and the exhaust gas is stably supplied to the turbocharger .

Further, in the engine system, when the load of the engine body is lowered to be smaller than the lower switching load, the engine may be configured to open the extraction valve after closing the opening / closing valve. Even in this case, there is no case in which a flow path with a small resistance is formed even temporarily, and the exhaust gas can be stably supplied to the supercharger.

The engine system may further include a power turbine outlet pipe for discharging the exhaust gas passing through the power turbine, wherein the extract pipe is connected to the power turbine outlet pipe, and the gas extracted from the power turbine inlet pipe May be discharged to the power turbine outlet pipe. According to such a configuration, even when the power turbine is driven by the crankshaft of the engine body when the power turbine is not driven by the exhaust gas, the gas passing through the power turbine is circulated through the circulating flow path including the addition pipe, The occurrence of an excessive load on the main body can be suppressed.

The engine system may further include an air inlet pipe connected between a portion of the power turbine outlet pipe to which the extracting pipe is connected and the power turbine and capable of receiving outside air into the power turbine outlet pipe, And an air intake valve provided in the intake pipe, wherein the air intake valve is closed when the first condition is satisfied, and the air intake valve is opened when the second condition is satisfied. According to such a configuration, since the gas in the circulating flow path is changed, the temperature of the gas in the circulating flow path can be prevented from rising excessively.

The engine system further includes a supercharger outlet pipe for exhausting the exhaust gas passing through the supercharger, wherein the supercharging pipe is connected to the supercharger outlet pipe, and the gas extracted from the power turbine inlet pipe is introduced into the supercharger It may be discharged to an outlet pipe. According to such a configuration, since the circulating flow path as described above is not formed in the beginning, the temperature of the gas in the circulating flow path does not rise excessively.

Further, a ship according to an example of the present invention includes any one of the engine systems described above.

As described above, according to the engine system of the above example, the waste heat energy can be efficiently recovered and the system can be simplified.

Further, according to the engine system according to another example, when the power turbine is not driven by the exhaust gas, it is possible to suppress the occurrence of an excessive load on the engine body.

1 is an overall view of an engine system according to a first embodiment.
2 is a control system block diagram of the engine system.
3 is a flowchart showing control contents of the engine system.
Fig. 4 is a graph showing the appropriate range of the atmospheric pressure.
5 is an overall view of the engine system according to the second embodiment.
6 is an overall view of the engine system according to the third embodiment.

Hereinafter, an engine system according to an embodiment 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)

≪ Overall configuration of engine system >

First, the entire configuration of the engine system 100 according to the first embodiment will be described. 1 is an overall view of an engine system 100 according to the present embodiment. 1, an engine system 100 according to the present embodiment is a so-called cycle for navigating a ship 101 and includes an engine body 10, a turbocharger 20, a power turbine 30, various pipes 41 to 45, and various valves 51, 52. Hereinafter, these will be sequentially described.

The engine body 10 is a device that is the center of the engine system 100. The engine main body 10 of this embodiment is a so-called low speed diesel engine. The engine main body 10 is for rotating a propeller shaft 103 having a propeller 102 mounted on a tip end thereof and includes a forward rotation in which a propulsion force is generated in a direction in which the ship 101 advances, It is possible to perform the reverse rotation in which the propulsive force is generated. The propeller shaft 103 is connected to a crankshaft 11 and the crankshaft 11 is connected to a plurality of pistons 12. Each of the pistons 12 reciprocates in accordance with the fuel explosion in the cylinder 13, and the crankshaft 11 rotates by the reciprocating motion of each piston 12. The engine body 10 is provided with an engine speed meter 14 for measuring the speed of rotation of the crankshaft 11, that is, the speed of rotation of the engine body 10.

The engine main body 10 is provided with a common scavenging pipe 15 on the upstream side of each cylinder 13 and a common exhaust pipe 16 on the downstream side of each cylinder 13. The scavenging line 15 collects the compressed air in the turbocharger 20 and supplies it to each cylinder 13. The scavenging tube 15 is provided with a small barometer 17 for measuring the pressure in the scavenging tube 15 (hereinafter referred to as "small pressure"). The exhaust pipe 16 collects the exhaust gas discharged from the cylinder 13 and supplies it to the turbocharger 20 and the power turbine 30. The engine body 10 is provided with the scavenging pipe 15 and the exhaust pipe 16 so that the pulsation generated in accordance with the combustion cycle of each cylinder 13 can be suppressed. Further, when the load on the engine body 10 (hereinafter referred to as "engine load") is increased, the amount of exhaust gas discharged from the engine body 10 is also increased.

The supercharger 20 is a device for compressing the air taken in from the outside and supplying the compressed air to the engine main body 10. The supercharger 20 has a turbine section 21 and a compressor section 22. The exhaust gas discharged from the engine body 10 (exhaust pipe 16) is supplied to the turbine section 21. [ The turbine section 21 rotates using the energy of the exhaust gas supplied from the exhaust pipe 16. The exhaust gas having passed through the turbine section 21 is delivered to the flue via the supercharger outlet pipe 46. The compressor section 22 is connected to the turbine section 21 via a connecting shaft 23. Accordingly, as the turbine section 21 rotates, the compressor section 22 also rotates. The compressor unit 22 compresses the air taken in from the outside and supplies the compressed air to the scavenging line 15. When the engine load is small, the amount of exhaust gas discharged from the engine body 10 is smaller than that required by the turbocharger 20. However, the amount of exhaust gas discharged from the engine body 10 increases as the engine load increases And gradually increases beyond the amount required by the turbocharger 20.

The power turbine 30 is a device for assisting the engine body 10 using the energy of the exhaust gas. The power turbine (30) has a turbine section (31) and a variable nozzle (32). When the exhaust gas is supplied to the power turbine 30, the turbine portion 31 is rotated by the energy of the supplied exhaust gas. The turbine section 31 is connected to the crankshaft 11 of the engine body 10 through a speed reducer 33 so that the rotational power of the turbine section 21 is transmitted to the crankshaft 11 through the speed reducer 33 do. Further, the rotation direction of the power turbine 30 is constant when rotating by the exhaust gas, and the engine main body 10 can be assisted only when the engine main body 10 is rotated forward.

The variable nozzles 32 are provided on the inlet side of the power turbine 30 and are mainly constituted by a plurality of movable vanes arranged in an annular shape. The opening area (opening degree) of the variable nozzle 32 can be adjusted by changing the angle of the movable vane. The variable nozzle 32 can change the inflow speed to the turbine section 21 by adjusting the opening degree, thereby efficiently operating the power turbine 30. That is, when the flow rate of the exhaust gas supplied to the power turbine 30 is large, the opening of the variable nozzle 32 is increased and when the flow rate of the exhaust gas supplied to the power turbine 30 is small, Reduces opening. On the other hand, the variable nozzle 32 functions also as a "throttle" since the opening area is changed. In this embodiment, the function of the variable nozzle 32 as a throttle is very important. That is, in this embodiment, by controlling the opening degree of the variable nozzle 32, not only the power turbine 30 (turbine section 31) is efficiently rotated, but also the amount of exhaust gas supplied to the turbocharger 20 (The ratio of the amount of exhaust gas supplied to the supercharger 20 to the amount of exhaust gas exhausted from the engine 10) (exhaust gas flow rate control).

The engine system 100 according to the present embodiment is provided with a supercharger inlet pipe 41, a power turbine inlet pipe 42, a power turbine outlet pipe 43, a diverter pipe 44 and an engine inlet pipe 45 . The supercharger inlet pipe 41 connects the exhaust pipe 16 and the turbine portion 21 of the turbocharger 20 and is a pipe for delivering the exhaust gas discharged from the engine body 10 to the supercharger 20 . The power turbine inlet pipe 42 branches off from the supercharger inlet pipe 41 and extends to the power turbine 30 and is connected to a pipe 42 for leading part of the exhaust gas in the supercharger inlet pipe 41 to the power turbine 30 to be. The power turbine outlet pipe 43 is disposed on the downstream side of the power turbine 30 and is a pipe for leading the exhaust gas passed through the power turbine 30 to the flue. The additional piping 44 is a piping connecting the downstream portion of the power turbine inlet piping 42 to the power turbine outlet piping 43, which will be described later. The engine inlet pipe 45 connects the compressor 22 and the scavenging pipe 15 of the turbocharger 20 and delivers the compressed air from the turbocharger 20 to the scavenging pipe 15.

The on-off valve 51 is a valve provided in the power turbine inlet pipe 42. The on-off valve 51 is closed when the engine body 10 is rotated in reverse (when the ship 101 is reversed) and when the engine load is small. The power turbine 30 and the engine body 10 (the crankshaft 11) rotate in a direction in which they become mutual resistance when the engine body 10 is rotating in the reverse direction. 30 so that the power turbine 30 is not driven. When the engine load is small, the amount of the exhaust gas discharged from the engine body 10 is small. Therefore, unless all the exhaust gas is supplied to the supercharger 20, the temperature of the combustion chamber member of the engine body 10 rises. Therefore, when the engine load is small, all the exhaust gas discharged from the engine body 10 is supplied to the supercharger 20 by closing the on-off valve 51. [ The valve 51 of the present embodiment may be a valve capable of maintaining two states of "open" and "closed ", but may be a valve capable of adjusting the opening degree.

The extraction valve 52 is a valve provided in the extraction pipe 44. The power turbine 30 and the crankshaft 11 are connected to each other while the power turbine 30 is not driven by the exhaust gas when the on-off valve 51 is closed, During rotation, the power turbine 30 is driven by the crankshaft 11 (engine body 10). At this time, the power turbine 30 acts like a blower. In the present embodiment, when the opening / closing valve 51 is closed, the extraction valve 52 is opened to form a circulation flow path through which the gas passing through the power turbine 30 circulates (circulation flow path formation control). That is, when the engine main body 10 is rotated in the forward and reverse directions by opening the extraction valve 52 when the open / close valve 51 is closed, the gas flows into the power turbine outlet pipe 43, the power turbine 30 The power turbine inlet piping 42, the extract piping 44, and the power turbine outlet piping 43 in this order. In FIG. 1, a circulating flow path in the counterclockwise direction is formed.

If there is no additional piping 44 and the extraction valve 52 and the circulation flow path is not formed when the opening / closing valve 51 is closed, the following problems arise. The power turbine 30 tries to send the gas in the power turbine outlet pipe 43 to the power turbine inlet pipe 42 regardless of whether the engine body 10 rotates in the forward direction or the reverse direction. However, if the opening / closing valve 51 is closed, the pressure in the power turbine inlet pipe 42 gradually increases and the pressure difference between the front and the rear of the power turbine 30 increases. As a result, . Therefore, in the present embodiment, the circulation flow path is formed when the opening / closing valve 51 is closed to avoid the above problem. Further, in the case of the present embodiment, a valve capable of maintaining two states of "open" and "closed" is sufficient, but it may be a valve capable of adjusting the opening degree.

Next, the setting of the engine system 100 will be described. As described above, when the opening / closing valve 51 is open, the amount of exhaust gas supplied to the turbocharger 20 is adjusted according to the opening degree of the variable nozzle 32. Here, the opening of the variable nozzle 32 for supplying an appropriate amount of exhaust gas to the supercharger 20 is referred to as "adequate amount supply opening degree ". At this time, a predetermined amount of exhaust gas is supplied to the power turbine 30, and when the amount of the exhaust gas flows to the power turbine 30, the variable nozzle 32, in which the power turbine 30 can rotate most efficiently, Is referred to as "maximum efficiency opening. &Quot; In this case, the engine system 100 according to the present embodiment is set such that the "adequate amount of supply opening degree" and "maximum efficiency opening degree" . That is, when the opening degree of the variable nozzle 32 is adjusted to supply an appropriate amount of exhaust gas to the turbocharger 20 in any engine load, the engine system 100 is inevitably required to be set so that the power turbine 30 is inevitably rotated efficiently . This setting can be changed by changing the combination of the turbine blades of the turbine section 31 of the power turbine 30 and the variable nozzle 32 or by changing the main items of the turbo nozzle of the turbocharger 20, the turbine blades, the compressor wheel, For example.

<Configuration of control system>

Next, the configuration of the control system in the engine system 100 will be described. The engine system 100 is provided with a control device 60 for controlling the entire engine system 100. The control device 60 is composed of a CPU, a ROM, a RAM, and the like. Fig. 2 is a block diagram of the control system of the engine system 100. Fig. 2, the control device 60 includes a driving operation panel 104 for operating the ship 101, an engine rotation system 14 for measuring the number of revolutions of the engine body 10, A fuel injection amount indicator 18 for measuring the amount of fuel to be injected, and a small barometer 17 for measuring the small pressure. The control device 60 acquires various information such as the rotational direction of the engine body 10, the engine speed, the amount of fuel input, and the atmospheric pressure in accordance with input signals from these devices.

In addition, the control device 60 controls various parts of the engine system 100 by performing various calculations according to input signals from the respective devices. In the present embodiment, the control device 60 is electrically connected to the open / close valve 51, the extraction valve 52, and the variable nozzle 32, 51, the extraction valve 52, and the variable nozzle 32, as shown in Fig.

In addition, the control device 60 has, as a functional configuration, a valve control section 61 and a variable nozzle control section 62. Among them, the valve control section 61 controls the opening and closing of the on-off valve 51 and the bleed valve 52, and performs the circulating flow path forming control described later. On the other hand, the variable nozzle control unit 62 is a part for determining the opening degree of the variable nozzle 32, and performs the exhaust gas flow rate control, which will be described later. Hereinafter, circulating flow path formation control performed by the control device 60 and exhaust gas flow rate control will be sequentially described.

&Lt; Circulation flow forming control &

First, circulating flow path formation control will be described with reference to FIG. Fig. 3 is a flowchart showing the control contents of the engine system 100. Fig. While the engine system 100 is operating, the control device 60 repeats the cycle of steps S1 to S16 in Fig. In Fig. 3, steps S1 to S10 correspond to circulating flow path formation control. The circulating flow forming control is a control for forming a circulating flow path of the gas passing through the power turbine 30 by opening the extraction valve 52 when the opening / closing valve 51 is closed, as already described in the outline.

First, the control device 60 acquires various kinds of information (step S1). Specifically, the control device 60 acquires the rotational direction of the engine body, the engine speed, the amount of fuel input, and the small pressure in accordance with an input signal from each device.

Next, the control device 60 determines whether or not the engine body 10 is in the normal rotation (step S2). When the engine main body 10 is in the reverse rotation (NO in step S2), the process proceeds to step S3 when the engine main body 10 is in the forward rotation state (YES in step S2) , The process proceeds to step S4. In the step S4, the opening / closing valve 51 is closed and the extraction valve 52 is opened, and then the process returns to the step S1. Thus, closing the opening / closing valve 51 when the engine body 10 is in the reverse rotation is for preventing the power turbine 30 and the crankshaft 11 from canceling the power from each other. The opening of the bleed valve 52 when the on-off valve 51 is closed is intended to reduce the engine load by forming a circulating flow path through which the gas passing through the power turbine 30 circulates, as described above.

In step S3, it is determined whether or not the on-off valve 51 is closed and the bleed valve 52 is open in the present situation. That is, in step S3, it is determined (confirmed) how the opening and closing of the opening and closing valve 51 and the extraction valve 52 is determined in the preceding cycle. In addition, at least when the opening / closing valve 51 is open at the time of the judgment of the step S3, the bleed valve 52 is necessarily closed, and when the opening / closing valve 51 is closed, the bleeding valve 52 is always opened. When the control device 60 determines that the on-off valve 51 is closed and the bleed valve 52 is open (YES in step S3), the controller 60 proceeds to step S5. When it is determined that the on-off valve 51 is open and the bleed valve 52 is closed (NO in step S3), the process proceeds to step S6.

In step S5, the engine load is calculated in accordance with the number of revolutions of the engine body 10 and the amount of fuel input, and it is determined whether or not the engine load is equal to or greater than the increase switching load. Since it is determined in step S3 that the open / close valve 51 is closed, the process proceeds to step S5. Therefore, in at least one cycle, it can be said that the control for closing the open / close valve 51 has been performed. The closing of the opening / closing valve 51 is because the engine load is small and the exhaust gas can not be supplied to the power turbine 30. Thus, in step S5, it is judged whether the engine load is small enough to supply exhaust gas to the power turbine 30 or ascended to such an extent that the exhaust gas can be supplied to the power turbine 30. That is, the "upward switching load" in the step S5 is an engine load when the engine load becomes high and the exhaust gas can be supplied to the power turbine 30, and in this embodiment, for example, And a load of 50% assuming that the maximum load of the engine body 10 is 100%).

When the engine load is equal to or greater than the increase switching load (YES in step S5), it is possible to supply the exhaust gas to the power turbine 30 in step S5, And opens the bleed valve 52 (step S7). However, in the present embodiment, instead of closing the on-off valve 51 and opening the bleed valve 52, the on-off valve 51 is opened after a certain period of time after the bleed valve 52 is closed. If both the opening and closing valve 51 and the bleed valve 52 are opened temporarily when the bleed valve 52 is closed at the same time the opening and closing valve 51 is opened and the gas in the power turbine inlet pipe 42 flows into the power turbine A bypass flow path is formed which passes through the additional piping 44 to the power turbine outlet piping 43 without passing through the bypass pipe 30. Since this flow path has a small resistance, a large amount of exhaust gas flows into this flow path, and as a result, the amount of exhaust gas passing through the supercharging inlet pipe 41 decreases. As a result, the pressure of the air supplied from the supercharger 20 fluctuates and the engine body 10 may become unstable. On the other hand, in the present embodiment, the amount of the exhaust gas flowing through the turbocharger 20 is prevented from being reduced at once by opening the on-off valve 51 after the extraction valve 52 is closed. After step S7, the process proceeds to step S11.

When the engine load is smaller than the upward switching load (NO in step S5), the exhaust gas can not be continuously supplied to the power turbine 30 in step S5, Is closed and the extraction valve 52 is kept open (step S8). After step S8, the process returns to step S1.

In step S6, the engine load is calculated in accordance with the engine speed and the fuel input amount acquired in step S1, and it is determined whether or not the engine load is equal to or less than the fall switching load. Since it is determined in step S3 that the open / close valve 51 is open, the flow advances to step S6, so that control for opening the on / off valve 51 is performed in at least one cycle. The opening / closing valve 51 is opened because the engine load is large and the exhaust gas can be supplied to the power turbine 30. Based on this, in step S6, it is determined whether the engine load is large enough to supply the exhaust gas to the power turbine 30, or whether the engine load has decreased to such an extent that the exhaust gas can not be supplied to the power turbine 30 . That is, the "lower switching load" in step S6 is the engine load when the engine load has fallen and the exhaust gas can no longer be supplied to the power turbine 30. In this embodiment, for example, A load of 45% when the maximum load of the engine main body is taken as 100%). The difference between the lower switching load and the higher switching load is due to the so-called hysteresis.

When the engine load is equal to or greater than the lower switching load (YES in step S6), the state where the exhaust gas can be continuously supplied to the engine body 10 is maintained in step S6, The valve 51 is opened and the extraction valve 52 is kept closed (step S9). After step S9, the process proceeds to step S11.

When the engine load is smaller than the lower switching load (YES in step S6), the exhaust gas can not be supplied to the power turbine 30, And opens the extraction valve 52 (step S10). In this embodiment, instead of closing the on-off valve 51 and opening the bleed valve 52, the bleed valve 52 is opened after a certain period of time after the on-off valve 51 is closed. The reason for opening the bleed valve 52 after closing the on-off valve 51 is the same as that described in the section of step S7 in order to suppress the amount of the exhaust gas flowing through the turbocharger 20 from being reduced at once to be. After step S10, the process returns to step S1.

&Lt; Exhaust gas flow rate control &

Next, the exhaust gas flow rate control will be described. Steps S11 to S16 in Fig. 3 are parts for exhaust gas flow rate control. The exhaust gas flow rate control is a control for efficiently operating the power turbine 30 while supplying an appropriate amount of exhaust gas to the turbocharger 20 by adjusting the opening degree of the variable nozzle 32 installed in the power turbine 30. The exhaust gas flow rate control is performed after step S7 or step S9. That is, the exhaust gas flow rate control is performed only when the on-off valve 51 is open. Whether or not an appropriate exhaust gas can be supplied to the turbocharger 20 can be judged by the small air pressure. That is, when the atmospheric pressure is higher than the predetermined value, the amount of the exhaust gas to be supplied to the supercharger 20 is excessive, and when the atmospheric pressure is lower than the predetermined value, it is determined that the amount of the exhaust gas to be supplied to the supercharger 20 is insufficient can do.

First, the control device 60 sets a suitable range of the atmospheric pressure (step S11). Here, FIG. 4 is a graph showing the range of the atmospheric pressure. The horizontal axis in Fig. 4 is the engine load, and the vertical axis is the small pressure. Of the two straight lines in the drawing, the upper straight line represents the upper and lower subatmospheric pressures, and the lower line represents the lower and lower subatmospheric pressures. The portion between these two straight lines is the appropriate small pressure range. For example, as shown in FIG. 4, when the engine load is L ₁ , the lower limit low pressure becomes P _L and the upper limit lower pressure becomes P _H. The lower and upper sub-atmospheric pressures vary depending on the engine load and are set larger as the engine load increases. In the actual step S11, a suitable small pressure range is calculated by using the equation representing the straight line in Fig.

Subsequently, the control device 60 determines whether the actual small pressure obtained in step S1 is within an appropriate range (step S12). That is, it is determined whether or not the actual depressurization pressure is greater than the lower limit lower limit pressure set in step S11, and is smaller than the upper limit lower limit pressure. If the small pressure is within the proper range (YES in step S12), the opening of the variable nozzle 32 is maintained (step S13), and the process returns to step S1. This is because an appropriate amount of exhaust gas is supplied to the supercharger 20 without changing the opening degree of the variable nozzle 32. As described above, the power turbine 30 is inevitably driven efficiently when the amount of exhaust gas is supplied to the turbocharger 20 by adjusting the opening degree of the variable nozzle 32.

On the other hand, if the small pressure is not within the proper range (NO in step S12), it is determined whether or not the actual small pressure is greater than the proper range (step S14) (YES in step S14), the opening degree of the variable nozzle 32 is increased (step S15, and the process returns to step S1) The amount of exhaust gas flowing to the turbocharger 20 side is increased by increasing the opening degree of the variable nozzle 32. In short, The ratio of the amount of the exhaust gas to be supplied to the supercharger 20 to the amount of exhaust gas discharged from the supercharger 10 is reduced. , The power turbine 30 is inevitably driven efficiently The.

If it is determined in step S14 that the actual small pressure is not larger than the proper range (NO in step S14), the opening degree of the variable nozzle 32 is decreased (step S16) ). In this case, since the actual atmospheric pressure is not greater than the proper range, the actual atmospheric pressure is smaller than the appropriate range (smaller than the lower limit atmospheric pressure). Since the amount of exhaust gas is insufficient in the turbocharger 20, control is performed to reduce the opening of the variable nozzle 32 to increase the amount of exhaust gas flowing to the turbocharger 20 side. That is, the ratio of the amount of exhaust gas supplied to the supercharger 20 to the amount of exhaust gas discharged from the engine body 10 is increased. In this manner, the exhaust gas is supplied to the supercharger 20 in an appropriate amount, so that the power turbine 30 is inevitably driven efficiently.

As described above, the engine system 100 according to the present embodiment has the extraction pipe 44 and the extraction valve 52. When the opening / closing valve 51 is closed, the extraction valve 52 is opened and the power turbine 30 To form a circulating flow path of the gas passing through the gas flow path. Therefore, even when the power turbine 30 is driven by the crankshaft 11 when the opening / closing valve 51 is closed, the differential pressure across the power turbine 30 does not become too large and an excessive load is generated in the engine body 10 Can be suppressed.

The engine system 100 according to the present embodiment not only improves the efficiency of the power turbine 30 by the variable nozzle 32 of the power turbine 30 but also improves the efficiency of the power turbine 30 by adjusting the amount of exhaust gas Can be adjusted. Therefore, the entire control and configuration of the engine system 100 can be simplified.

(Modification of First Embodiment)

The open / close valve 51 is opened when the engine body 10 is not rotating and the load of the engine body 10 is larger than the predetermined switching load (hereinafter referred to as "first condition"), (Fully closed) when the engine main body 10 is in the reverse rotation or when the load of the engine main body 10 is smaller than the switching load (hereinafter referred to as "second condition"). However, at the time of the second condition, the opening / closing valve 51 may be closed instead of being closed. That is, the " opening / closing valve is closed "in steps S3 and S8 of Fig. 3 is changed to" It is also good to carry out the control which reads "the opening / closing valve as an introduction road".

Here, the "introduction figure" is an opening degree smaller than the opening degree of the opening / closing valve 51 in the first condition, and includes the first introduction and the second introduction. The first introductory drawing is an opening of the opening / closing valve 51 when the exhaust gas passed through the opening / closing valve 51 is at the boundary between the state where the exhaust gas is conveyed by the power turbine 30 and the state where the power turbine 30 is driven . The second introductory diagram is an opening degree of the opening / closing valve 51 when the first introduction degree is smaller than the first introduction degree and a little exhaust gas flows into the circulating flow path.

As described above, when the on-off valve 51 is closed and the bleed valve 52 is opened, the gas passing through the power turbine 30 passes through the power turbine 30 again through the circulating flow path, There is a possibility that the gas temperature in the power turbine 30 is excessively increased due to the energy from the power turbine 30. On the other hand, assuming that the opening / closing valve 51 is the first introduction degree or the opening degree at the time of the second condition, the energy received by the gas in the circulation flow path from the power turbine 30 decreases and the gas temperature in the circulation flow path rises excessively Can be suppressed. Further, at the time of the second condition, when the opening / closing valve 51 is the second introduction road, the exhaust gas flows slightly into the circulating flow path and the gas of the circulating flow path is changed, so that the temperature of the gas in the circulating flow path can be suppressed from rising excessively .

(Second Embodiment)

Next, a second embodiment will be described with reference to Fig. 5 is an overall view of the engine system 200 according to the second embodiment. 5, the engine system 200 according to the present embodiment is provided with the air intake pipe 47, the air intake valve 53, and the power turbine outlet valve 54, Which is different from the engine system 100 according to the first embodiment. The other points are basically the same as those of the engine system 100 according to the first embodiment.

The air inlet pipe 47 is connected between the power turbine outlet pipe 43 and the power turbine 30 to which the additional pipe 44 is connected and receives the outside air to the power turbine outlet pipe 43 . The air intake valve 53 is provided in the air intake pipe 47, and the opening and closing thereof is controlled by the control device 60. The power turbine outlet valve 54 is formed between the portion of the power turbine outlet pipe 43 to which the extract pipe 44 is connected and the portion to which the air inlet pipe 47 is connected, Is controlled by the device (60).

In the circulating path forming control of the present embodiment, when the opening valve 51 is opened and the extraction valve 52 is closed (at the time of the first condition), the air intake valve 53 is closed, the opening / closing valve 51 is closed, And opens the air inlet valve 53 when the air conditioner 52 is opened (at the time of the second condition).

Since the engine system 200 according to the present embodiment is configured as described above, when the gas is circulated through the circulating flow passage through the power turbine 30 due to the opening / closing valve 51 being closed and the extraction valve 52 being opened (Air and exhaust gas) of the circulating flow path are changed, and the gas temperature of the circulating flow path is prevented from rising excessively because the outside air is also received in the power turbine outlet pipe 43 through the air inlet pipe 47 .

The power turbine outlet valve 54 is opened when the opening / closing valve 51 is opened and the extracting valve 52 is closed (at the time of the first condition), and the opening / closing valve 51 is closed and the extracting valve 52 is opened When (when the second condition) is closed. By controlling in this way, when the outside air is received in the power turbine outlet pipe 43 through the air intake pipe 47, it is possible to prevent the exhaust gas from being taken in from the flue. As a result, the temperature of the gas in the circulating flow path can be further restrained from rising excessively.

(Third Embodiment)

Next, the third embodiment will be described with reference to Fig. 6 is an overall view of an engine system 300 according to the third embodiment. 6, in the engine system 300 according to the present embodiment, the connection positions of the additional piping 44 and the power turbine outlet piping 43 are different from each other in the case of the engine system 100 according to the first embodiment different. The other points are basically the same as those of the engine system 100 according to the first embodiment.

In this embodiment, the power turbine outlet pipe 43 is connected to the supercharger outlet pipe 46. Thus, the exhaust gas having passed through the power turbine 30 is delivered to the flue gas through the power turbine outlet pipe 43 and the supercharger outlet pipe 46. The additional piping 44 is connected to the downstream portion of the power turbine inlet pipe 42 downstream of the opening and closing valve 51 and the downstream portion of the turbocharger outlet pipe 46 to which the power turbine outlet pipe is connected It is connected.

When the on-off valve 51 is closed and the bleed valve 52 is opened, the circulating flow path as in the first embodiment is not formed, and the power turbine inlet The gas extracted from the pipe 42 is discharged to the supercharger outlet pipe 46. Therefore, the gas passing through the power turbine 30 does not pass through the power turbine 30 again, and the temperature of the gas gradually increases due to the energy of the power turbine 30, so that the gas does not excessively rise.

Although the embodiment has been described with reference to the drawings, the specific structure is not limited to these embodiments, and design changes and the like that do not depart from the gist of the present invention are included in the present invention.

In addition, in the case of abnormality such as the damage of some parts of the engine system, such as when the turbocharger and the power turbine reach dangerous revolutions or the atmospheric pressure reaches the dangerous atmosphere pressure, the operation of the engine system have. However, it is needless to say that the engine system is included in the present invention as long as the control according to the present invention is performed at a normal time.

In the engine system according to the embodiment, although the power turbine is always connected to the crankshaft through the speed reducer, for example, even if the clutch is installed between the reducer and the crankshaft so that the connection between the power turbine and the crankshaft can be released When the power turbine and the crankshaft are connected, there arises a problem that an excessive load is applied to the engine body when the opening / closing valve is closed.

The power turbine inlet pipe and the supercharger inlet pipe are separately formed and each is connected to the exhaust pipe to the supercharger or from the exhaust pipe to the power turbine, although the power turbine inlet pipe is branched at the supercharger inlet pipe Or may be configured to transport the exhaust gas.

Further, in the above embodiment, the case where the engine system is mounted on a ship has been described. However, an engine system used in a power generation facility is naturally included in the present invention as long as it has the configuration of the present invention.

The engine system according to an example of the present invention can efficiently recover the waste heat energy and can simplify the system. Further, the engine system according to another example of the present invention can suppress an excessive load on the engine body when the power turbine is not driven by the exhaust gas. Thus, the engine system of the present invention is beneficial in the technical field of engine systems.

10: engine body 11: crankshaft
15: Scavenger 20: Supercharger
30: power turbine 32: variable nozzle
41: supercharger inlet piping 42: power turbine inlet piping
43: Power turbine outlet piping 44: Extraction piping
47: air inlet pipe 51: opening / closing valve
52: extraction valve 53: air intake valve
100, 200, 300: engine system 101: ship

Claims (13)

An engine body,
A supercharger driven by an exhaust gas discharged from the engine body,
A power turbine driven by an exhaust gas discharged from the engine body and connected to a crankshaft of the engine body,
A supercharger inlet pipe for guiding the exhaust gas discharged from the engine body to the supercharger,
A power turbine inlet pipe for leading the exhaust gas discharged from the engine body to the power turbine,
An on-off valve provided on the power turbine inlet pipe for opening and closing in accordance with an operation condition of the engine body;
A supplementary pipe connected to a portion of the power turbine inlet pipe downstream of the open / close valve, for extracting gas in the power turbine inlet pipe;
And a bleed valve provided in the bleed pipe,
Closing valve is closed while the engine body is rotating forward and the load of the engine body is a first condition that is greater than a predetermined switching load,
Closing valve in the first condition when the engine body is in the reverse rotation or in a second condition in which the load of the engine body is smaller than the predetermined switching load, Respectively,
The introductory diagram includes a first introductory diagram and a second introductory diagram,
The first introduction view is an opening degree of the on-off valve when the exhaust gas passing through the on-off valve is in a boundary between a state where the exhaust gas is conveyed by the power turbine and a state in which the power turbine is driven,
Wherein the second introduction degree is an opening degree of the opening / closing valve when the first introduction degree is smaller than the first introduction degree and the exhaust gas flows into the power turbine side than the opening / closing valve.
An engine body,
A supercharger driven by an exhaust gas discharged from the engine body,
A power turbine driven by an exhaust gas discharged from the engine body and connected to a crankshaft of the engine body,
A supercharger inlet pipe for guiding the exhaust gas discharged from the engine body to the supercharger,
A power turbine inlet pipe for leading the exhaust gas discharged from the engine body to the power turbine,
An on-off valve provided on the power turbine inlet pipe for opening and closing in accordance with an operation condition of the engine body;
A supplementary pipe connected to a portion of the power turbine inlet pipe downstream of the opening / closing valve to extract gas in the power turbine inlet pipe;
And a bleed valve provided in the bleed pipe,
Closing valve is closed while the engine body is rotating forward and the load of the engine body is a first condition that is greater than a predetermined switching load,
Closing valve or an introduction which is smaller than the opening degree of the opening / closing valve under the first condition when the engine body is in the reverse rotation or in a second condition in which the load of the engine body is smaller than the predetermined switching load And is configured to open the extraction valve,
Further comprising a power turbine outlet pipe for exhausting exhaust gas passing through the power turbine,
Wherein the additional piping is connected to the power turbine outlet pipe and discharges the gas extracted from the power turbine inlet pipe to the power turbine outlet pipe,
Wherein the power turbine outlet pipe is connected between a portion to which the extracting pipe is connected and the power turbine and includes an air inlet pipe capable of receiving outside air into the power turbine outlet pipe and an air inlet valve Further comprising:
The air intake valve is closed when the first condition is satisfied and the air intake valve is opened when the second condition is satisfied.
3. The method of claim 2,
Wherein the power turbine inlet pipe is branched from the supercharger inlet pipe and is configured to lead a part of the exhaust gas in the supercharger inlet pipe to the power turbine.
3. The method of claim 2,
Wherein the upward switching load, which is the switching load when the load of the engine body is rising, is set to be larger than the downward switching load which is the switching load when the load of the engine body is falling.
5. The method of claim 4,
And opens the on / off valve after closing the extraction valve when the load of the engine body rises and becomes larger than the upward switching load.
5. The method of claim 4,
And when the load of the engine body is lowered to become smaller than the lower switching load, the engine is opened after closing the opening / closing valve.
An engine body,
A supercharger driven by an exhaust gas discharged from the engine body,
A power turbine driven by an exhaust gas discharged from the engine body and connected to a crankshaft of the engine body,
A supercharger inlet pipe for guiding the exhaust gas discharged from the engine body to the supercharger,
A power turbine inlet pipe for leading the exhaust gas discharged from the engine body to the power turbine,
An on-off valve installed on the power turbine inlet pipe for opening and closing according to an operation condition of the engine main body,
A supplementary pipe connected to a portion of the power turbine inlet pipe downstream of the opening / closing valve to extract gas in the power turbine inlet pipe;
And a bleed valve provided in the bleed pipe,
Closing valve is closed while the engine body is rotating forward and the load of the engine body is a first condition that is greater than a predetermined switching load,
Closing valve when the engine body is in the reverse rotation or the load of the engine body is smaller than the predetermined switching load, the opening degree of the opening / closing valve is smaller than the opening degree of the opening / closing valve under the first condition, And configured to open the valve,
A supercharger outlet pipe for exhausting the exhaust gas passing through the turbocharger and a power turbine outlet pipe for exhausting exhaust gas passing through the power turbine,
Wherein the additional pipe is connected to the supercharger outlet pipe and discharges the gas extracted from the power turbine inlet pipe to the supercharger outlet pipe,
The power turbine outlet pipe is connected to the supercharger outlet pipe,
Wherein the additional piping is connected to a portion on the downstream side of a portion of the supercharger outlet piping where the power turbine outlet piping is connected.
delete delete A ship characterized by comprising the engine system according to any one of claims 1 to 7.
delete delete delete

Images