JP2012225179A - Supercharger system, internal combustion engine and control method of supercharger system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a supercharger system which can more efficiently recover exhaust energy, an internal combustion engine, and a control method of the supercharger system.SOLUTION: The supercharger system includes: a first supercharger 6 which has a turbine 6a driven with exhaust gas from an engine body 3 and a compressor 6b driven by the turbine 6a to transfer the outside air to the engine body 3; a second supercharger 7 which has a generator 7d having a rotating shaft 7c connected to rotating shafts of a turbine 7a and a compressor 7b; a first exhaust pipe 12 which supplies the exhaust gas from the engine body 3 to the turbine 6a of the first supercharger 6; a cut valve 9 which is provided in the first exhaust pipe 12 and can intercept a current of the exhaust gas; and a controller 30 which obtains the number of revolutions of the first supercharger 6 or the second supercharger 7, and controls opening and closing of the cut valve 9 based on the number of revolutions.

Description

  The present invention relates to a supercharger system including one turbocharger having a turbine section and a compressor section, and another supercharger further having a generator, an internal combustion engine, and a supercharger system control method.

  By providing a turbocharger in a diesel engine, for example, a marine two-cycle diesel engine, exhaust energy of exhaust gas discharged from the engine body is recovered as power. Some turbochargers are connected to a generator and generate power by receiving power.

  Patent Document 1 includes a plurality of superchargers to which exhaust gas is supplied from an engine body and a power turbine including a generator, or at least one of the plurality of superchargers has a generator. In the case of providing, a technology for recovering exhaust energy as power even when the engine load is low is disclosed.

JP 2009-257097 A

  In ship navigation, long-time deceleration navigation has become common due to the recent increase in fuel. Under such conditions, since the engine load is low, the amount of exhaust gas is reduced, and the power generation output of the generator-equipped supercharger (hybrid supercharger) is limited. As a result, the generator-equipped supercharger cannot exhibit sufficient performance.

  Therefore, when a plurality of superchargers are provided, the exhaust gas inlets of some of the superchargers are blocked to increase the amount of exhaust gas flowing into the remaining superchargers and increase the number of turbochargers. The engine scavenging pressure can be increased. As a result, the amount of air flowing into the cylinder is increased, the combustion situation is improved, and the fuel consumption rate is improved. In addition, by increasing the amount of exhaust gas flowing into the turbocharger with the generator by closing the exhaust gas inlets other than the turbocharger with the generator among the plurality of turbochargers, the scavenging pressure of the engine is increased. The power generation output can be obtained.

  On the other hand, in the prior art such as Patent Document 1, the opening / closing control of the exhaust gas inlet for supplying the exhaust gas to the supercharger is only performed according to the engine load.

  The present invention has been made in view of such circumstances, and provides a supercharger system, an internal combustion engine, and a supercharger system control method capable of more efficiently recovering exhaust energy. With the goal.

In order to solve the above-described problems, the supercharger system, internal combustion engine, and supercharger system control method of the present invention employ the following means.
That is, the supercharger system according to the present invention includes a first supercharger that includes a turbine unit that is driven by exhaust gas guided from the engine body, and a compressor unit that is driven by the turbine unit to pump outside air to the engine body. A turbine unit driven by exhaust gas guided from the engine body, a compressor unit driven by the turbine unit to pump outside air to the engine body, and a rotating shaft coupled to the rotating shafts of the turbine unit and the compressor unit A second supercharger having a power generator, an exhaust pipe for supplying exhaust gas from the engine body to the turbine section of the first supercharger, and an exhaust pipe provided to block the flow of exhaust gas A possible shut-off valve, and a control unit that acquires the rotational speed of the first supercharger or the second supercharger and controls opening and closing of the shut-off valve based on the rotational speed.

  According to this invention, the rotation speed of a 1st supercharger or a 2nd supercharger is acquired, and the cutoff valve provided in the exhaust pipe is opened and closed based on the acquired rotation speed. Therefore, when the shutoff valve is in the open state, the exhaust gas is supplied to the turbine portion of the first supercharger through the exhaust pipe. At this time, the exhaust gas is also supplied to the turbine section of the second supercharger, and power is generated by the generator.

  On the other hand, when the shut-off valve is in the closed state, the supply of exhaust gas to the first supercharger is shut off, and the exhaust gas is supplied only to the turbine portion of the second supercharger. As a result, the exhaust gas that has been supplied to the first supercharger is supplied to the second supercharger. Therefore, for example, when the amount of exhaust gas from the engine body decreases and the rotation speed of the first supercharger or the second supercharger decreases, the amount of power generated by the generator of the second supercharger decreases. However, by closing the shut-off valve, the rotation speed of the second supercharger increases, and a decrease in the amount of power generation can be suppressed.

  For example, the rotation speed acquired is compared with a predetermined threshold value, and when the rotation speed becomes equal to or less than the threshold value, the control unit controls the shut-off valve to be closed. This threshold value is determined based on, for example, the number of revolutions when the generator of the second supercharger effectively generates power. The rotation speed of the first supercharger or the second supercharger may be obtained by direct measurement, or calculated from the air flow rate, the compressor inlet temperature, the compressor inlet pressure, the compressor outlet pressure, and the compressor specifications. May be.

  In addition, a supercharger system according to the present invention includes a first supercharger that includes a turbine unit that is driven by exhaust gas guided from an engine body, and a compressor unit that is driven by the turbine unit and pumps outside air to the engine body. A turbine unit driven by exhaust gas guided from the engine body, a compressor unit driven by the turbine unit to pump outside air to the engine body, and a rotating shaft coupled to the rotating shafts of the turbine unit and the compressor unit A second supercharger having a power generator, an exhaust pipe for supplying exhaust gas from the engine body to the turbine section of the first supercharger, and an exhaust pipe provided to block the flow of exhaust gas Possible shut-off valves, exhaust turbine work by exhaust gas supplied to the first or second supercharger, and the amount of air required for the output of the engine body. Turbocharger or second superchargers and a control unit for controlling the compressor work to get the opening and closing of the exhaust turbine work and shut-off valve on the basis of the compressor work when pumped into the engine body.

  According to this invention, the exhaust gas turbine work by the exhaust gas supplied to the first supercharger or the second supercharger and the amount of air required for the output of the engine main body are converted into the first supercharger or the second supercharger. The compressor work when the machine is pumped to the engine body is acquired, and the shut-off valve provided in the exhaust pipe is opened and closed based on the acquired exhaust turbine work and compressor work. Therefore, when the shutoff valve is in the open state, the exhaust gas is supplied to the turbine portion of the first supercharger through the exhaust pipe. At this time, the exhaust gas is also supplied to the turbine section of the second supercharger, and power is generated by the generator.

  On the other hand, when the shut-off valve is in the closed state, the supply of exhaust gas to the first supercharger is shut off, and the exhaust gas is supplied only to the turbine portion of the second supercharger. As a result, the exhaust gas that has been supplied to the first supercharger is supplied to the second supercharger. Therefore, for example, the amount of exhaust gas from the engine body decreases, the exhaust turbine work of the first supercharger or the second supercharger decreases, and the amount of air required for the output of the engine body decreases. When the compressor work decreases, the amount of power generated by the generator of the second supercharger decreases. By closing the shut-off valve, the exhaust turbine work of the second supercharger increases, Reduction can be suppressed.

  When the output of the engine body decreases, the amount of compressor work decreases relatively compared to the exhaust turbine work. Therefore, surplus energy can be used for power generation by the generator of the second supercharger. For example, the difference between the acquired exhaust turbine work and the compressor work is compared with a predetermined threshold value, and when the difference becomes equal to or greater than the threshold value, the control unit controls the shut-off valve to the closed state. This threshold value is determined based on, for example, the difference when the difference between the exhaust turbine work and the compressor work is recovered by the generator and the generator generates power effectively. The exhaust turbine work is calculated from, for example, an air flow rate, a fuel flow rate, a turbine inlet temperature, and a turbine inlet pressure.

  Moreover, the internal combustion engine which concerns on this invention is provided with an engine main body, and said supercharger system is provided.

  According to this invention, when the output is reduced in the engine body, the supply of the exhaust gas to the first supercharger is shut off, and the corresponding exhaust gas is supplied to the second supercharger. A decrease in power generation can be suppressed.

  The supercharger system control method according to the present invention includes a turbine section that is driven by exhaust gas guided from the engine body, and a compressor section that is driven by the turbine section and that pumps outside air to the engine body. 1 a turbocharger, a turbine section driven by exhaust gas guided from the engine body, a compressor section driven by the turbine section to pump outside air to the engine body, and a rotating shaft of the turbine section and the compressor section. A second supercharger having a generator having a rotating shaft, an exhaust pipe for supplying exhaust gas from the engine body to the turbine section of the first supercharger, and an exhaust pipe provided to block the flow of exhaust gas A control method for a turbocharger system comprising: a shut-off valve that can perform a step of obtaining a rotational speed of the first supercharger or the second supercharger; And a step of opening and closing the shutoff valve based on.

  According to this invention, the rotation speed of a 1st supercharger or a 2nd supercharger is acquired, and the cutoff valve provided in the exhaust pipe is opened and closed based on the acquired rotation speed. Therefore, when the shutoff valve is in the open state, the exhaust gas is supplied to the turbine portion of the first supercharger through the exhaust pipe. At this time, the exhaust gas is also supplied to the turbine section of the second supercharger, and power is generated by the generator.

  On the other hand, when the shut-off valve is in the closed state, the supply of exhaust gas to the first supercharger is shut off, and the exhaust gas is supplied only to the turbine portion of the second supercharger. As a result, the exhaust gas that has been supplied to the first supercharger is supplied to the second supercharger. Therefore, for example, when the amount of exhaust gas from the engine body decreases and the rotation speed of the first supercharger or the second supercharger decreases, the amount of power generated by the generator of the second supercharger decreases. However, by closing the shut-off valve, the rotation speed of the second supercharger increases, and a decrease in the amount of power generation can be suppressed.

  The supercharger system control method according to the present invention includes a turbine section that is driven by exhaust gas guided from the engine body, and a compressor section that is driven by the turbine section and that pumps outside air to the engine body. 1 a turbocharger, a turbine section driven by exhaust gas guided from the engine body, a compressor section driven by the turbine section to pump outside air to the engine body, and a rotating shaft of the turbine section and the compressor section. A second supercharger having a generator having a rotating shaft, an exhaust pipe for supplying exhaust gas from the engine body to the turbine section of the first supercharger, and an exhaust pipe provided to block the flow of exhaust gas A turbocharger system control method comprising a shutoff valve capable of performing exhaust gas, and an exhaust turbine using exhaust gas supplied to the first supercharger or the second supercharger Based on the work, the compressor work when the first supercharger or the second supercharger pumps the amount of air required for the output of the engine body to the engine body, and the exhaust turbine work and the compressor work Opening and closing the shut-off valve.

  According to this invention, the exhaust gas turbine work by the exhaust gas supplied to the first supercharger or the second supercharger and the amount of air required for the output of the engine main body are converted into the first supercharger or the second supercharger. The compressor work when the machine is pumped to the engine body is acquired, and the shut-off valve provided in the exhaust pipe is opened and closed based on the acquired exhaust turbine work and compressor work. Therefore, when the shutoff valve is in the open state, the exhaust gas is supplied to the turbine portion of the first supercharger through the exhaust pipe. At this time, the exhaust gas is also supplied to the turbine section of the second supercharger, and power is generated by the generator.

  On the other hand, when the shut-off valve is in the closed state, the supply of exhaust gas to the first supercharger is shut off, and the exhaust gas is supplied only to the turbine portion of the second supercharger. As a result, the exhaust gas that has been supplied to the first supercharger is supplied to the second supercharger. Therefore, for example, the amount of exhaust gas from the engine body decreases, the exhaust turbine work of the first supercharger or the second supercharger decreases, and the amount of air required for the output of the engine body decreases. When the compressor work decreases, the amount of power generated by the generator of the second supercharger decreases. By closing the shut-off valve, the exhaust turbine work of the second supercharger increases, Reduction can be suppressed.

  When the output of the engine body decreases, the amount of compressor work decreases relatively compared to the exhaust turbine work. Therefore, surplus energy can be used for power generation by the generator of the second supercharger. For example, the difference between the acquired exhaust turbine work and the compressor work is compared with a predetermined threshold value, and when the difference becomes equal to or greater than the threshold value, the control unit controls the shut-off valve to the closed state. This threshold value is determined based on, for example, the difference when the difference between the exhaust turbine work and the compressor work is recovered by the generator and the generator generates power effectively. The exhaust turbine work is calculated from, for example, an air flow rate, a fuel flow rate, a turbine inlet temperature, and a turbine inlet pressure.

  According to the present invention, exhaust energy can be recovered more efficiently.

It is a lineblock diagram showing a marine diesel engine concerning a 1st embodiment of the present invention. It is a graph which shows the relationship between a supercharger rotation speed and an engine output. It is a flowchart which shows operation | movement of the supercharger system which concerns on 1st Embodiment of this invention. It is a graph which shows the relationship between exhaust turbine work or compressor work, and energy. It is a flowchart which shows operation | movement of the supercharger system which concerns on 2nd Embodiment of this invention.

Embodiments according to the present invention will be described below with reference to the drawings.
[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIG.
As shown in FIG. 1, the supercharger system according to the present embodiment includes a first supercharger 6, a second supercharger 7, a first exhaust pipe 12, a cut valve (shutoff valve) 9, The control unit 30 and the like are provided. The supercharger system of this embodiment is applied to the marine diesel engine 1, for example. The marine diesel engine 1 includes a fuel pump 2, a diesel engine main body (for example, a two-cycle diesel engine) 3, and the like.

  A screw propeller (not shown) is directly or directly connected to a crankshaft (not shown) constituting the diesel engine main body (hereinafter referred to as “engine main body”) 3 via a propeller shaft (not shown). It is attached indirectly. Further, the engine body 3 is provided with a cylinder portion 4 including a cylinder liner (not shown), a cylinder cover (not shown) and the like, and each cylinder portion 4 is connected to a crankshaft. A piston (not shown) is arranged.

  Fuel is supplied to the engine body 3 via the fuel pump 2 and the supply pipe 10, and the fuel is combusted in each cylinder portion 4.

  Further, an exhaust port (not shown) of each cylinder portion 4 is connected to the exhaust collecting pipe 5. The exhaust collecting pipe 5 is connected to the inlet side of the turbine section 6 a of the first supercharger 6 through the first exhaust pipe 12, and the turbine section of the second supercharger 7 through the second exhaust pipe 19. 7a is connected to the inlet side. On the other hand, an air supply port (not shown) of each cylinder portion 4 is connected to a scavenging chamber 8, and the scavenging chamber 8 is connected to a compressor portion 6 b of the first supercharger 6 through an air supply pipe 17. In addition, the compressor unit 7 b of the second supercharger 7 is connected via the air supply pipe 24.

  The first supercharger 6 is driven by an exhaust gas (combustion gas) guided from the engine body 3 via the exhaust collecting pipe 5 and the first exhaust pipe 12, and is driven by the turbine part 6a. The compressor 6b that pumps outside air to the engine body 3 and a casing (not shown) that is provided between the turbine 6a and the compressor 6b and supports them are mainly configured. It is.

  The casing is inserted with a rotating shaft 6c having one end projecting toward the turbine section 6a and the other end projecting toward the compressor section 6b. One end portion of the rotating shaft 6c is attached to a turbine disk (not shown) of a turbine rotor (not shown) constituting the turbine portion 6a, and the other end portion of the rotating shaft 6c is a compressor portion. It is attached to a hub (not shown) of a compressor impeller (not shown) constituting 6b.

  A cut valve 9 that is opened and closed by the control unit 30 is connected midway through the first exhaust pipe 12. The cut valve 9 supplies exhaust gas from the engine body 3 to the first supercharger in the open state, and shuts off the supply of exhaust gas in the closed state.

  The second supercharger 7 is driven by exhaust gas guided from the engine body 3 through the exhaust collecting pipe 5 and the second exhaust pipe 19, and is driven by the turbine section 7a to be driven by the engine body. 3, a compressor part 7b for pumping outside air, a casing (not shown) provided between and supporting the turbine part 7a and the compressor part 7b, and a generator driven by the turbine part 7a to generate electric power 7d is the main element.

  A rotating shaft 7c having one end projecting toward the turbine section 7a and the other end projecting to the compressor section 7b is inserted into the casing. One end portion of the rotating shaft 7c is attached to a turbine disk (not shown) of a turbine rotor (not shown) constituting the turbine portion 7a, and the other end portion of the rotating shaft 7c is a compressor portion. It is attached to a hub (not shown) of a compressor impeller (not shown) constituting 7b.

  The rotating shaft of the turbine part 7a and the rotating shaft of the generator 7b are connected via a coupling. That is, the rotating shaft of the generator 7d rotates together with the rotating shaft of the turbine unit 7a.

  The generator 7d is electrically connected to a switchboard or the like separately installed in the ship (for example, the engine room), and the generator 7d can use (use) the power generated as the generator as the ship power. it can.

  The exhaust gas that has passed through the turbine parts 6a and 7a is led to a funnel (not shown) via exhaust pipes 14 and 21 connected to the outlet sides of the turbine parts 6a and 7a, respectively, and then discharged outside the ship. Is done.

  A silencer (not shown) is disposed in the air supply pipes 15 and 22 connected to the respective inlet sides of the compressor parts 6b and 7b, and the outside air that has passed through the silencer is compressed by the compressor parts 6b and 7b. Each led to In addition, an air cooler (not shown) and a surge tank (not shown) are connected in the middle of the supply pipes 17 and 24 connected to the outlet side of the compressor parts 6b and 7b. The outside air that has passed through 6b and 7b passes through the air cooler and the surge tank, and is then supplied to the scavenging chamber 8 connected to the engine body 3.

  The supply pipe 10, the first exhaust pipe 12, the second exhaust pipe 19, and the supply pipes 15, 17, 22, and 24 are provided with detection units 11, 13, 20, 16, 18, 23, and 25, respectively. The detection unit 11 has a flow rate sensor, for example, and detects the flow rate of the fuel supplied to the engine body 3. The detection units 16 and 23 have a flow rate sensor, a temperature sensor, and a pressure sensor, and measure the flow rate of air supplied to the compressor units 6b and 7b, the input temperature and the inlet pressure of the compressor units 6b and 7b. The detection units 18 and 25 have, for example, pressure sensors, and measure the outlet pressures of the compressor units 6b and 7b. The detection units 13 and 20 have a flow rate sensor, a temperature sensor, and a pressure sensor, and measure the flow rate of exhaust gas supplied to the turbine units 6a and 7a, the input temperature and the inlet pressure of the turbine units 6a and 7a.

  Further, the first supercharger 6 and the second supercharger 7 may be provided with a rotational speed measurement sensor (not shown), and the rotational speed measurement sensor may measure the rotational speed of the rotating shaft.

  The control part 30 acquires the rotation speed of the 1st supercharger 6 or the 2nd supercharger 7, and opens and closes the cut valve 9 provided in the 1st exhaust pipe 12 based on the acquired rotation speed. For example, the rotation speed acquired is compared with a predetermined threshold value, and the control unit 30 controls the cut valve 9 to be closed when the rotation speed is equal to or less than the threshold value. This threshold value is determined based on, for example, the number of revolutions when the generator 7d of the second supercharger 7 effectively generates power. The rotational speed of the first supercharger 6 or the second supercharger 7 may be obtained by directly measuring, the air flow rate, the inlet temperature of the compressor units 6b and 7b, the inlet pressure of the compressor units 6b and 7b, It may be calculated from the outlet pressure of the compressor units 6b and 7b, the specifications of the compressor units 6b and 7b, and the like.

  Next, the operation of the supercharger system according to the present embodiment will be described with reference to FIG.

  First, an air flow rate, a fuel flow rate, an inlet temperature of the compressor units 6b and 7b, an inlet pressure of the compressor units 6b and 7b, and an outlet pressure of the compressor units 6b and 7b are acquired (step S1). And based on the air flow rate, the fuel flow rate, the inlet temperature of the compressor units 6b and 7b, the inlet pressure of the compressor units 6b and 7b, the outlet pressure of the compressor units 6b and 7b, the specifications of the compressor units 6b and 7b, etc. The rotation speed of the first supercharger 6 or the second supercharger 7 is calculated (step S2). Here, it is assumed that the rotation speed of the first supercharger 6 or the second supercharger 7 is acquired by executing Step S1 and Step S2, but the first supercharger 6 or the second supercharger is obtained. The rotation speed of the machine 7 may be a value directly measured by a rotation speed measurement sensor.

  Next, the calculated rotation speed is compared with a predetermined threshold value (step S3). As shown in FIG. 2, when the engine output is high and exhaust gas is sufficiently supplied from the engine body 3 to the first supercharger 6 or the second supercharger 7, the first supercharger 6 or the second supercharger is supplied. The rotation speed of the feeder 7 is large. On the other hand, as the engine output decreases and the exhaust gas amount decreases, the rotational speed of the first supercharger 6 or the second supercharger 7 also decreases.

  If the rotation speed of the first supercharger 6 or the second supercharger 7 is equal to or greater than a predetermined threshold value, the first supercharger 6 and the second supercharger 7 remain open with the cut valve 9 open. Exhaust gas is supplied to both. On the other hand, when the rotation speed of the 1st supercharger 6 or the 2nd supercharger 7 becomes smaller than a predetermined threshold value, the cut valve 9 is made into a closed state (step S4). At this time, the supply of the exhaust gas to the first supercharger 6 is interrupted, and the exhaust gas is supplied only to the turbine section 7a of the second supercharger 7. As a result, the exhaust gas that has been supplied to the first supercharger 6 is supplied to the second supercharger 7. Therefore, when the amount of exhaust gas from the engine body 3 decreases and the rotational speed of the first supercharger 6 or the second supercharger 7 decreases, the amount of power generated by the generator 7c of the second supercharger 7 However, when the cut valve 9 is closed, the rotational speed of the second supercharger 7 is increased as shown in FIG.

  Therefore, even if the engine output is low load, the engine output range in which the second supercharger 7 can obtain a rotational speed that is equal to or higher than a predetermined threshold and can obtain electric power by the second supercharger 7. Can be spread. Further, when the engine load is low, the exhaust turbine work generated in the turbine section 7a by the exhaust energy exceeds the compressor work required for air compression required in the engine body 3. Therefore, surplus energy can be recovered by the generator 7d, and the fuel consumption rate in the marine diesel engine 1 can be improved.

[Second Embodiment]
Next, a supercharger system according to a second embodiment of the present invention will be described with reference to FIGS. 4 and 5.

  In the first embodiment described above, the case where the opening / closing of the cut valve 9 is controlled according to the rotational speed of the first supercharger 6 or the second supercharger 7 has been described. In the second embodiment, the exhaust turbine is controlled. Based on the work, the opening and closing of the cut valve 9 is controlled. Below, description is abbreviate | omitted about the component which overlaps with 1st Embodiment.

  The control unit 30 shown in FIG. 1 determines the exhaust turbine work by the exhaust gas supplied from the engine body 3 to the first supercharger 6 or the second supercharger 7 and the amount of air required for the output of the engine body 3. The compressor work when the first supercharger 6 or the second supercharger 7 is pumped to the engine body 3 is acquired. And the control part 30 opens and closes the cut valve 9 provided in the 1st exhaust pipe 12 based on the acquired exhaust turbine work and compressor work. For example, the difference between the acquired exhaust turbine work and the compressor work is compared with a predetermined threshold value, and when the difference becomes equal to or greater than the threshold value, the control unit 30 controls the cut valve 9 to be closed. This threshold is determined based on, for example, the difference between the exhaust turbine work and the compressor work when the difference between the exhaust turbine work and the compressor work is recovered by the generator 7d and the generator 7d performs effective power generation. The exhaust turbine work is calculated from, for example, an air flow rate, a fuel flow rate, a turbine inlet temperature, and a turbine inlet pressure.

  The relationship between the exhaust turbine work and the compressor work and the engine output is as shown in FIG. The solid line in FIG. 4 shows the relationship between the exhaust turbine work and the engine output, and the broken line in FIG. 4 shows the relationship between the compressor work and the engine output. Regardless of engine power, exhaust turbine work is greater than compressor work.

  The lower the engine load is, the more the exhaust turbine work generated in the turbine section 7a by the exhaust gas from the engine body 3 is relatively more than the compressor work required for air compression required in the engine body 3. large. Therefore, surplus energy can be recovered by the generator 7d, and the fuel consumption rate in the marine diesel engine 1 can be improved.

  Next, the operation of the supercharger system according to the present embodiment will be described with reference to FIG.

  First, an air flow rate, a fuel flow rate, an inlet temperature of the turbine parts 6a and 7a, and an inlet pressure of the turbine parts 6a and 7a are acquired (step S11). Then, the exhaust turbine work is calculated based on the air flow rate, the fuel flow rate, the inlet temperature of the turbine parts 6a and 7a, and the inlet pressure of the turbine parts 6a and 7a. Further, in consideration of the efficiency of the first supercharger 6 and the efficiency of the second supercharger 7, the first supercharger 6 and the second supercharger 7 set the amount of air required for a certain engine output. Compressor work for pressure feeding to the engine body 3 is calculated (step S12).

  Next, the calculated difference between the exhaust turbine work and the compressor work is compared with a predetermined threshold (step S13). If the difference between the exhaust turbine work and the compressor work of the first supercharger 6 or the second supercharger 7 is equal to or greater than a predetermined threshold value, the first supercharger 6 and the second supercharger 6 are kept with the cut valve 9 open. Exhaust gas is supplied to any of the two superchargers 7. On the other hand, when the difference between the exhaust turbine work and the compressor work of the first supercharger 6 or the second supercharger 7 becomes smaller than a predetermined threshold value, the cut valve 9 is closed (step S14). At this time, the supply of the exhaust gas to the first supercharger 6 is interrupted, and the exhaust gas is supplied only to the turbine section 7a of the second supercharger 7. As a result, the exhaust gas that has been supplied to the first supercharger 6 is supplied to the second supercharger 7. Therefore, when the amount of exhaust gas from the engine body 3 decreases and the rotational speed of the first supercharger 6 or the second supercharger 7 decreases, the amount of power generated by the generator 7c of the second supercharger 7 However, when the cut valve 9 is closed, the rotation speed of the second supercharger 7 is increased, and a decrease in the amount of power generation can be suppressed.

  Therefore, when the engine load is low, the exhaust turbine work generated in the turbine section 7a by the exhaust energy is relatively higher than the compressor work necessary for air compression required in the engine body 3. Therefore, when the engine load is low, surplus energy can be recovered by the generator 7d, and the fuel consumption rate in the marine diesel engine 1 can be improved.

DESCRIPTION OF SYMBOLS 1 Marine diesel engine 2 Fuel pump 3 Engine main body 4 Cylinder part 5 Exhaust collecting pipe 6 1st supercharger 6a, 7a Turbine part 6b, 7b Compressor part 6c, 7c Rotating shaft 7 2nd supercharger 7d Generator 8 Scavenging chamber 9 Cut valve (shutoff valve)
11, 13, 16, 18, 20, 23, 25 Detector 12 First exhaust pipe (exhaust pipe)
15, 17, 22, 24 Supply pipe 19 Second exhaust pipe 30 Control unit

Claims (5)

A first turbocharger having a turbine section driven by exhaust gas guided from the engine body, and a compressor section driven by the turbine section to pump outside air to the engine body;
The turbine unit is driven by exhaust gas guided from the engine body, the compressor unit is driven by the turbine unit to pump outside air to the engine body, and the turbine unit and the rotation shaft of the compressor unit are connected to each other. A second supercharger having a generator having a rotating shaft;
An exhaust pipe for supplying the exhaust gas from the engine body to the turbine portion of the first supercharger;
A shut-off valve provided in the exhaust pipe and capable of shutting off the flow of the exhaust gas;
A controller that obtains the rotational speed of the first supercharger or the second supercharger, and controls opening and closing of the shut-off valve based on the rotational speed;
A supercharger system comprising. A first turbocharger having a turbine section driven by exhaust gas guided from the engine body, and a compressor section driven by the turbine section to pump outside air to the engine body;
The turbine unit is driven by exhaust gas guided from the engine body, the compressor unit is driven by the turbine unit to pump outside air to the engine body, and the turbine unit and the rotation shaft of the compressor unit are connected to each other. A second supercharger having a generator having a rotating shaft;
An exhaust pipe for supplying the exhaust gas from the engine body to the turbine portion of the first supercharger;
A shut-off valve provided in the exhaust pipe and capable of shutting off the flow of the exhaust gas;
Exhaust turbine work by the exhaust gas supplied to the first supercharger or the second supercharger, and the amount of air required for the output of the engine main body are set as the first supercharger or the second supercharger. A controller that obtains compressor work when a machine is pumped to the engine body, and controls opening and closing of the shutoff valve based on the exhaust turbine work and the compressor work;
A supercharger system comprising. Equipped with an engine body,
An internal combustion engine provided with the supercharger system according to claim 1 or 2. A first turbocharger having a turbine section driven by exhaust gas guided from the engine body, and a compressor section driven by the turbine section to pump outside air to the engine body;
The turbine unit is driven by exhaust gas guided from the engine body, the compressor unit is driven by the turbine unit to pump outside air to the engine body, and the turbine unit and the rotation shaft of the compressor unit are connected to each other. A second supercharger having a generator having a rotating shaft;
An exhaust pipe for supplying the exhaust gas from the engine body to the turbine portion of the first supercharger;
A shut-off valve provided in the exhaust pipe and capable of shutting off the flow of the exhaust gas;
A method for controlling a turbocharger system comprising:
Obtaining the rotational speed of the first supercharger or the second supercharger;
Opening and closing the shut-off valve based on the rotational speed;
A method for controlling a turbocharger system. A first turbocharger having a turbine section driven by exhaust gas guided from the engine body, and a compressor section driven by the turbine section to pump outside air to the engine body;
The turbine unit is driven by exhaust gas guided from the engine body, the compressor unit is driven by the turbine unit to pump outside air to the engine body, and the turbine unit and the rotation shaft of the compressor unit are connected to each other. A second supercharger having a generator having a rotating shaft;
An exhaust pipe for supplying the exhaust gas from the engine body to the turbine portion of the first supercharger;
A shut-off valve provided in the exhaust pipe and capable of shutting off the flow of the exhaust gas;
A method for controlling a turbocharger system comprising:
Exhaust turbine work by the exhaust gas supplied to the first supercharger or the second supercharger, and the amount of air required for the output of the engine main body are set as the first supercharger or the second supercharger. Obtaining compressor work when the machine pumps to the engine body;
Opening and closing the shutoff valve based on the exhaust turbine work and the compressor work;
A method for controlling a turbocharger system.

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