JP6700860B2 - Control device for internal combustion engine and internal combustion engine - Google Patents

Description

  The present invention relates to a control device for an internal combustion engine that includes a supercharger, and an internal combustion engine that includes the control device for the internal combustion engine.

For example, an internal combustion engine as a main engine mounted on a ship is equipped with a supercharger in order to improve fuel efficiency and reduce CO ₂ in exhaust gas. This supercharger drives exhaust gas discharged from an internal combustion engine to drive a turbine and a compressor to compressively supply combustion gas to the internal combustion engine to improve the output of the internal combustion engine.

  As such a supercharger, there is a variable turbine system including a variable capacity turbine. In this variable turbine system, a variable turbine nozzle is arranged at an exhaust gas inlet portion, an exhaust gas gas inlet passage is divided into two systems, and an opening/closing valve is provided in one gas inlet passage. Therefore, it is possible to change the nozzle throat area by the opening/closing operation of the opening/closing valve, and in the low load operation range of the internal combustion engine, the nozzle throat area can be reduced to increase the scavenging pressure and reduce the fuel consumption rate. . As such a technique, for example, there is one described in the following patent document.

JP, 2010-216468, A

  In the variable turbine system described above, the nozzle throat area is changed by the opening/closing operation of the opening/closing valve provided in the one gas inlet passage, and the scavenging pressure is controlled according to the operating state of the internal combustion engine. On the other hand, there are, for example, fuel injection time, fuel injection timing, exhaust valve drive time, exhaust valve opening/closing timing, etc., which are adjusted according to the operating state of the internal combustion engine, and these are controlled by preset operating parameters. ing. Therefore, there is a problem that the performance of the internal combustion engine varies when the scavenging pressure of the variable turbine displacement system changes.

  The present invention solves the above-mentioned problems, and provides an internal combustion engine control device and an internal combustion engine that reduce the behavior of the in-cylinder pressure in accordance with changes in the scavenging pressure to stabilize the performance of the internal combustion engine. The purpose is to

  The control device for an internal combustion engine of the present invention to achieve the above object is an internal combustion engine main body, a compressor connected to the internal combustion engine main body for supplying combustion gas to the internal combustion engine main body, and a coaxial with the compressor. A supercharger including a rotating variable capacity turbine, and an operating member that is provided in the internal combustion engine body and affects cylinder pressure, and determines an operation amount of the operating member according to the capacity of the turbine. A plurality of operating parameters are provided, and the operating parameters are switched after a predetermined delay time set in advance when the capacity of the turbine is changed.

  Therefore, when the turbine capacity is changed, the operating parameters of the operating member are switched after the elapse of a predetermined delay time, whereby the behavior of the in-cylinder pressure due to the change of the scavenging pressure and the switching of the operating parameters is reduced and the performance of the internal combustion engine is stabilized. Can be promoted.

  The control device for an internal combustion engine according to the present invention is characterized in that the operation parameter is switched after the delay time has elapsed from the time of outputting the turbine capacity change command.

  Therefore, by switching the operating parameters after the delay time has elapsed from the time of outputting the turbine capacity change command, it is possible to switch the operating parameters at an appropriate time regardless of the time required to change the turbine capacity.

  In the control device for an internal combustion engine of the present invention, when the capacity of the turbine is increased, the operating parameters are switched at the same time when the capacity of the turbine is changed, while when the capacity of the turbine is decreased, when the capacity of the turbine is changed. From the above, the operating parameter is switched after the lapse of the delay time.

  Therefore, when the turbine capacity increases, the scavenging pressure decreases, but when the turbine capacity decreases, the scavenging pressure increases, so that the operating parameters are switched after a delay time has elapsed since the turbine capacity was changed. Therefore, the rapid increase in the cylinder pressure is suppressed, and the reliability of the internal combustion engine can be improved.

  In the control device for an internal combustion engine of the present invention, the supercharger is provided with a switching valve capable of changing and switching the capacity of the turbine, and the delay time is a margin time preset in the switching time of the switching valve. The feature is that they are added and set.

  Therefore, by adding the allowance time to the switching time of the switching valve and setting the delay time, the operating parameters are switched after the switching valve has completely moved to the switching position, and the cylinder pressure can be rapidly changed by simple control. The rise can be suppressed.

  In the control device for an internal combustion engine of the present invention, a scavenging pressure or an in-cylinder pressure measurement estimating device for measuring or estimating the scavenging pressure or the in-cylinder pressure is provided, and the delay time is a constant value of the scavenging pressure or the in-cylinder pressure. It is characterized by the time it takes to reach.

  Therefore, by setting the time until the measured or estimated scavenging pressure or in-cylinder pressure reaches a certain value as a delay time, the operating parameters are switched while waiting for the in-cylinder pressure to stabilize, and the in-cylinder pressure suddenly changes. Can be suppressed.

  In the control device for the internal combustion engine of the present invention, the operating member is at least one of an exhaust valve, a fuel injection valve, and a hydraulically operated device.

  Therefore, the operating parameters such as the opening/closing timing of the exhaust valve, the fuel injection timing of the fuel injection valve, the fuel injection time, the operating pressure of the hydraulically operated device, etc. can be set to appropriate timings according to the turbine capacity.

  Further, an internal combustion engine of the present invention includes a main body of an internal combustion engine, a compressor connected to the main body of the internal combustion engine to supply combustion gas to the main body of the internal combustion engine, and a variable capacity turbine that rotates coaxially with the compressor. Machine, an operating member provided in the main body of the internal combustion engine for influencing cylinder pressure, and a plurality of operating parameters for determining the operating amount of the operating member according to the capacity of the turbine are provided. And a control device that switches the operation parameters after a predetermined delay time that has been set in advance is changed.

  Therefore, when the turbine capacity is changed, the operation parameters of the operating member are switched after a lapse of a predetermined delay time, whereby the behavior of the in-cylinder pressure due to the change of the scavenging pressure and the switching of the operation parameters is reduced, and the performance of the internal combustion engine is stabilized. Can be promoted.

  According to the control device for an internal combustion engine and the internal combustion engine of the present invention, the behavior of the in-cylinder pressure due to the change of the scavenging pressure and the switching of the operating parameters is reduced, and the performance of the internal combustion engine can be stabilized.

FIG. 1 is a schematic configuration diagram showing a marine diesel engine as an internal combustion engine of the present embodiment. FIG. 2 is a schematic diagram showing a VTI supercharger equipped with a variable capacity turbine. FIG. 3 is a time chart showing the supercharger switching control when the main engine load is constant by the control device of the internal combustion engine. FIG. 4 is a time chart showing the supercharger switching control when the load of the main engine is changed by the control device of the internal combustion engine.

  Exemplary embodiments of a control device for an internal combustion engine and an internal combustion engine according to the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that the present invention is not limited to this embodiment, and when there are a plurality of embodiments, the present invention also includes those configured by combining the respective embodiments.

  FIG. 1 is a schematic configuration diagram showing a marine diesel engine as an internal combustion engine of the present embodiment.

  In the present embodiment, as shown in FIG. 1, a marine diesel engine 10 as an internal combustion engine includes a diesel engine body (internal combustion engine body) 11, a VTI supercharger 12, and a control device 13.

  The diesel engine main body 11 is provided with a plurality of cylinder parts 21, each of which has a piston 22 supported therein so as to be reciprocally movable. Each piston 22 has a lower part of a piston rod 23. It is connected to the crankshaft via a crosshead (not shown).

  In the cylinder portion 21, a scavenging trunk 25 is connected via a scavenging port 24 provided on the lower portion, and an exhaust manifold 27 is connected to an exhaust port 26 provided on the upper portion. The scavenging trunk 25 is connected to a compressor (compressor) 31 of the VTI supercharger 12 via an intake pipe L1. The exhaust manifold 27 is connected to the turbine 32 of the VTI supercharger 12 via the exhaust pipe L2. Further, the cylinder part 21 is provided with an exhaust valve 28 for discharging exhaust gas to the exhaust port 26 at the upper part. Further, the cylinder part 21 is provided with an injector (fuel injection valve) 29 for injecting fuel (for example, heavy oil, natural gas, etc.) into the inside (combustion chamber).

  Therefore, when the piston 22 moves to the bottom dead center (the solid line position in FIG. 1), the scavenging port 24 opens, so that the combustion gas in the scavenging trunk 25 is introduced into the combustion chamber from the scavenging port 24, and the piston 22 rises. The piston 22 blocks the conduction between the scavenging port 24 and the combustion chamber. Further, by closing the exhaust port 26 with the exhaust valve 28, the combustion gas in the combustion chamber is compressed. When the piston 22 moves to the top dead center (the position indicated by the chain double-dashed line in FIG. 2), the pressure in the combustion chamber reaches a predetermined compression pressure, and the injector 29 injects fuel. Then, the combustion gas and the fuel are mixed and burned in the combustion chamber, and the piston 22 descends due to the combustion energy. At this time, the exhaust port 28 is opened by the exhaust valve 28, so that the exhaust gas (combustion gas) in the combustion chamber is discharged to the exhaust port 26.

  The exhaust valve 28 can be opened and closed by an exhaust valve operating device 41. The exhaust valve 28 is biased and supported by a biasing member (not shown) (for example, a compression spring, an air spring, etc.) in the direction of closing the exhaust port. The hydraulic oil supply pipe 42 has one end connected to a hydraulic oil tank (not shown), the other end connected to the exhaust valve 28, and an oil supply pump 43 provided in the middle. When the opening/closing valve 44 is opened from the state where the exhaust valve 28 closes the exhaust port 26 by the biasing member, the oil supply pump 43 is driven, and the hydraulic oil pressurized by the oil supply pump 43 passes through the hydraulic oil supply pipe 42. It is supplied to the exhaust valve actuating device 41 to lower the exhaust valve 28 against the biasing member. Then, the exhaust valve 28 opens the exhaust port 16 only while the opening/closing valve 44 is open.

  The injector 29 can inject fuel into the combustion chamber of the cylinder portion 21. A fuel tank (not shown) is connected to one end of the fuel supply pipe 46, the other end is connected to the injector 29, a fuel pump 47 is provided in the middle of the fuel supply pipe 46, and the opening/closing valve 48 is opened. The fuel pump 47 is driven, and the fuel pressurized by the fuel pump 47 is supplied to the injector 29 through the fuel supply pipe 46. Then, the injector 29 injects fuel into the combustion chamber of the cylinder portion 21 only while the on-off valve 48 is open.

  The VTI supercharger 12 is a VTI (Variable Turbine Inlet) supercharger including a variable capacity turbine capable of changing the turbine capacity in two stages. The VTI supercharger 12 is configured such that a compressor 31 and a turbine (axial flow turbine) 32 are coaxially connected via a rotating shaft 33, and the compressor 31 and the turbine 32 are integrally rotated by the rotating shaft 33. You can The compressor 31 is an outside air suction type, and an intake pipe L1 reaching the scavenging trunk 25 is connected. The turbine 32 is connected to an exhaust pipe L2 reaching the exhaust manifold 27, and is also connected to an exhaust pipe L4 for exhausting to the outside.

  Here, the VTI supercharger 12 will be described in detail. FIG. 2 is a schematic diagram showing a VTI supercharger equipped with a variable capacity turbine.

  In the VTI supercharger 12, as shown in FIG. 2, the gas inlet casing 50 is configured by integrally fastening an inner casing 51 and an outer casing 52, and is formed between the inner casing 51 and the outer casing 52. A main exhaust gas passage 54 for guiding the exhaust gas G to the turbine nozzle 53 is provided in the space. The main exhaust gas passage 54 is formed over the entire circumference in the rotation direction of the gas inlet casing 50, and the exhaust gas G introduced from the gas inlet portion 50 a of the gas inlet casing 50 passes through the main exhaust gas passage 54 and the gas outlet. After being guided to 50b, the gas is discharged from the outlet of the gas outlet casing 55 to the outside.

  The turbine nozzle 53 is provided at the gas outlet 50b of the gas inlet casing 50. The rotating shaft 33 is rotatably supported by a bearing (not shown), and the turbine 32 is integrally fixed to one end portion in the axial direction. The turbine 32 is provided with a plurality of turbine rotor blades 56 on the outer peripheral portion in the circumferential direction. The turbine rotor blade 56 is provided close to the downstream side that is the outlet of the turbine nozzle 53, and the high-temperature exhaust gas ejected from the turbine nozzle 53 passes through the turbine rotor blade 56 and expands, so that the turbine 32 is Rotate.

  In the inner casing 51, a sub-exhaust gas flow passage 57 is formed over the entire circumference in the rotation direction of the turbine 32 to guide the exhaust gas branched to the inner peripheral side in the middle of the main exhaust gas flow passage 54 to the inner peripheral side of the turbine nozzle 53. .. The auxiliary exhaust gas passage 57 is provided on the inner peripheral side of the main exhaust gas passage 54, and the main exhaust gas passage 54 and the auxiliary exhaust gas passage 57 are partitioned by a partition wall 58 forming the inner casing 51. There is.

  Further, one end of the connecting pipe 59 is connected to the inner casing 51 and communicates with the main exhaust gas passage 54, while the other end is connected to the inner casing 51 and communicates with the auxiliary exhaust gas passage 57. Further, the connecting pipe 59 is provided with an opening/closing valve (switching valve, for example, a butterfly valve) 60 in the middle thereof. Therefore, when the on-off valve 60 is opened, the exhaust gas G branched in the middle of the main exhaust gas passage 54 is guided to the auxiliary exhaust gas passage 57 through the passage inside the connecting pipe 59. Further, the turbine nozzle 53 is provided with a partition wall 61 for partitioning the inner peripheral side and the outer peripheral side of the turbine nozzle 53 so as to be continuous with the end portion of the partition wall 58 on the root side (rotation center side of the turbine 32). There is.

  Here, when the load of the marine diesel engine 10 is low and the amount of exhaust gas G is small, the on-off valve 60 is closed. Then, the entire amount of the exhaust gas G introduced from the gas inlet 50a of the gas inlet casing 50 is guided to the gas outlet 50b through the main exhaust gas passage 54. The exhaust gas G guided to the gas outlet 50b is sucked into the outer peripheral side of the turbine nozzle 53 (a space on the outer peripheral side of the partition wall 61), expands when passing through the turbine rotor blades 56, and passes through the turbine 32 and the rotary shaft 33. Rotate.

  On the other hand, when the load of the marine diesel engine 10 is high and the amount of exhaust gas G is large, the opening/closing valve 60 is opened. Then, the exhaust gas G introduced from the gas inlet 50a of the gas inlet casing 50 is guided to the gas outlet 50b through the main exhaust gas passage 54, and further through the connecting pipe 59 through the auxiliary exhaust gas passage 57 to the gas outlet 57a. Be led to. The exhaust gas G guided to the gas outlet 50b is sucked in on the outer peripheral side of the turbine nozzle 53, and the exhaust gas G guided to the gas outlet 57a is on the inner peripheral side of the turbine nozzle 53 (the space on the inner peripheral side of the partition wall 61). Are sucked in and are expanded when passing through the turbine rotor blades 56, thereby rotating the turbine 32 and the rotating shaft 33.

  Therefore, as shown in FIG. 1, the turbine 32 is driven by the exhaust gas (combustion gas) guided from the exhaust manifold 27 through the exhaust pipe L2, drives the compressor 31, and then discharges the exhaust gas from the exhaust pipe L4 to the outside. .. On the other hand, the compressor 31 is driven by the turbine 32, compresses a gas such as air sucked from the outside air, and then sends the compressed gas such as air as a combustion gas under pressure from the intake pipe L1 to the scavenging trunk 25.

  As shown in FIG. 1, the control device 13 can control opening/closing of the opening/closing valves 44, 48, 60. That is, the control device 13 controls the opening timing, closing timing, and driving time (opening time) of the exhaust valve 28 by opening/closing the opening/closing valve 44 according to the operating state of the marine diesel engine 10. Further, the control device 13 controls the fuel injection start timing, the fuel injection end timing, the fuel injection amount, and the fuel injection time by the injector 29 by opening/closing the opening/closing valve 48 according to the operating state of the marine diesel engine 10. . Further, the control device 13 controls the scavenging pressure by the VTI supercharger 12 by opening/closing the opening/closing valve 60 according to the operating state of the marine diesel engine 10.

  Here, the control device 13 is provided with a plurality of operation parameters that determine the operation amount of the operation member according to the turbine capacity of the turbine (variable capacity turbine) 32. Here, the actuating members are the exhaust valve 28 and the injector 29 described above, and there are various hydraulic operating devices other than the exhaust valve 28 and the injector 29. That is, the VTI supercharger 12 has a low load operation mode in which the opening/closing valve 60 is closed when the diesel engine main body 11 has a low load, and a high load operation mode in which the opening/closing valve 60 is opened when the diesel engine main body 11 has a high load. Is set. Therefore, the control device 13 switches between the low load operation mode and the high load operation mode according to the operation state of the diesel engine main body 11.

  On the other hand, the optimal opening timing, closing timing, and driving time of the exhaust valve 28 are set according to the operating state of the marine diesel engine 10, and the fuel injection start timing, fuel injection end timing, fuel injection amount, fuel of the injector 29 are set. The injection time is set. Therefore, the optimal opening timing, closing timing, drive time of the exhaust valve 28 according to the low load operation mode of the VTI supercharger 12, fuel injection start timing by the injector 29, fuel injection end timing, fuel injection amount, fuel injection time. The optimum opening timing, closing timing, driving time and fuel injection start timing of the injector 29, fuel injection end timing, fuel injection amount, fuel injection of the exhaust valve 28 according to the operating parameter A set by The operation parameter B whose time is set is set.

  When the operation mode of the VTI supercharger 12 switches between the low load operation mode and the high load operation mode, the control device 13 switches between the operation parameter A and the operation parameter B to optimally open the exhaust valve 28. The timing, the closing timing, the driving time, the fuel injection start timing by the injector 29, the fuel injection end timing, the fuel injection amount, and the fuel injection time are set.

Further, when the capacity of the turbine 32 increases due to the VTI supercharger 12 switching from the low load operation mode to the high load operation mode, the control device 13 switches the operation parameter A to the operation parameter B simultaneously with the mode switching. .. On the other hand, when the capacity of the turbine 32 decreases due to the VTI supercharger 12 switching from the high load operation mode to the low load operation mode, the control device 13 passes a predetermined delay time from the mode switching. After that, the operating parameter B is switched to the operating parameter A.

  In this case, since the control device 13 outputs the opening/closing command signal to the opening/closing valve 60 and the switching time from when the opening/closing valve 60 actually moves to the open position or the closed position occurs, the delay time is It is desirable to set the switching time of the on-off valve 60 by adding a preset margin time. Then, it is desirable that the switching time and the margin time of the on-off valve 60 are set based on the design data of the on-off valve 60 and the experimental data to be conducted in advance.

  The delay time is not limited to this setting method. For example, in the diesel engine main body 11, a pressure sensor (cylinder pressure measurement estimation device) that measures the pressure of the combustion chamber in the cylinder portion 21 (hereinafter, cylinder pressure) is provided, and when switching the mode of the VTI supercharger 12. The delay time may be set as a time period until the preset constant value (for example, the rate of change of the in-cylinder pressure reaches a predetermined value or less) after the in-cylinder pressure decreases or increases. In this case, a pressure sensor (cylinder pressure measurement estimation device) that measures the scavenging pressure may be used instead of the pressure sensor that measures the cylinder pressure. Further, the in-cylinder pressure and the scavenging pressure may be estimated from various detection data.

  Hereinafter, the switching control of the operation parameter associated with the switching of the operation mode of the VTI supercharger 12 will be described in detail. FIG. 3 is a time chart showing the supercharger switching control by the control device of the internal combustion engine when the main engine load is constant, and FIG. 4 is a time chart showing the supercharger switching control by the control device of the internal combustion engine when the main engine load changes. is there.

(When the load of the diesel engine 11 is constant and the turbine capacity increases)
As shown in FIGS. 1 and 3, the VTI supercharger 12 is set to the low load operation mode until the time t1, and the opening/closing valve 60 is closed, so that the total amount of the exhaust gas G is reduced to the main exhaust gas flow. It is sucked into the outer peripheral side of the turbine nozzle 53 through the passage 54 and rotates the turbine 32 and the compressor 31. Therefore, compared with the case where the load of the diesel engine main body 11 is the same and the on-off valve 60 is not closed, the rotation of the compressor 31 increases, the scavenging pressure increases, and the cylinder pressure also increases.

  When the load of the main engine and the scavenging pressure are constant, the control device 13 outputs the open/close valve 60 to the open/close valve 60 at time t1 when the open/close command signal for opening the open/close valve 60 is output. Is operated to the open side, the VTI supercharger 12 is switched to the high load operation mode. At this time, since the on-off valve 60 is gradually opened, the exhaust gas G also flows to the side of the sub-exhaust gas flow path 57 and the gas passage area of the turbine nozzle 53 increases, so the rotational speeds of the turbine 32 and the compressor 31 decrease. However, the scavenging pressure decreases and the in-cylinder pressure also decreases.

  Further, the control device 13 outputs the opening/closing command signal for opening the opening/closing valve 60, and at the same time, the operating parameter A is switched to the operating parameter B. Therefore, the maximum in-cylinder pressure sharply decreases until time t2 in response to changes in the opening timing of the exhaust valve 28, the fuel injection timing by the injector 29, and the time, but thereafter, it gradually decreases. When the on-off valve 60 moves to the open position at time t3, the scavenging pressure becomes stable and the in-cylinder pressure also becomes stable after time t4.

(When the load on the diesel engine 11 is constant and the turbine capacity decreases)
On the other hand, at time t5, when the opening/closing command signal for closing the opening/closing valve 60 is output to the opening/closing valve 60, the control device 13 operates the opening/closing valve 60 to the closing side, thereby causing VTI. The supercharger 12 switches to the low load operation mode. At this time, the opening/closing valve 60 is gradually closed, so that the nozzle passage area of the exhaust gas G flowing to the side of the sub-exhaust gas flow passage 57 is reduced, the rotational speeds of the turbine 32 and the compressor 31 are increased, and the scavenging pressure is increased. As the pressure rises, the cylinder pressure also rises.

  On the other hand, when outputting the opening/closing command signal for closing the opening/closing valve 60, the control device 13 does not switch from the operation parameter B to the operation parameter A, but at the time t7 after the lapse of the delay time t+Δt, from the operation parameter B. Switch to operating parameter A. Therefore, from the time t5 to the time t6, since the opening timing of the exhaust valve 28, the fuel injection timing by the injector 29, and the time are not changed, the maximum in-cylinder pressure gradually increases without rapidly increasing.

  After that, when the open/close valve 60 moves to the closed position at time t6, the delay time t+Δt elapses at time t7, so the control device 13 switches from the operation parameter B to the operation parameter A here. Then, after time t8, the scavenging pressure is stable and the in-cylinder pressure is also stable. Here, the delay time t+Δt is set by adding the margin time Δt to the switching time t of the opening/closing valve 60.

  When the control device 13 outputs the opening/closing command signal for closing the opening/closing valve 60, if the operation parameter B is switched to the operation parameter A, the opening timing of the exhaust valve 28, the fuel injection timing by the injector 29, and the time are changed. Is changed, there is a possibility that the maximum in-cylinder pressure rapidly increases and overshoots between time t5 and time t6. Further, if the operating parameter corresponding to the operation mode of the VTI supercharger 12 is not set, the maximum in-cylinder pressure in the low load operation mode of the VTI supercharger 12 as indicated by the chain double-dashed line in FIG. Will be low. On the other hand, by switching from the operation parameter B to the operation parameter A in the low load operation mode of the VTI supercharger 12, as shown by the solid line in FIG. High in-cylinder pressure can be maintained.

(When the load of the diesel engine 11 increases and the turbine capacity increases )
As shown in FIGS. 1 and 4, when the load on the main engine increases, at time t11, the control device 13 outputs an opening/closing command signal to the opening/closing valve 60 to open the opening/closing valve 60. Then, the opening/closing valve 60 is operated to the open side, whereby the VTI supercharger 12 is switched to the high load operation mode. At this time, since the on-off valve 60 is gradually opened, the exhaust gas G also flows to the side of the sub-exhaust gas passage 57 and the gas passage area of the turbine nozzle 53 increases, so that the rotational speeds of the turbine 32 and the compressor 31 decrease. However, the scavenging pressure decreases and the in-cylinder pressure also decreases.

  Further, the control device 13 outputs the opening/closing command signal for opening the opening/closing valve 60, and at the same time, the operating parameter A is switched to the operating parameter B. Therefore, the maximum in-cylinder pressure sharply decreases until time t12 in response to changes in the opening timing of the exhaust valve 28, the fuel injection timing by the injector 29, and the time, but thereafter, it gradually decreases. At time t13, when the on-off valve 60 moves to the open position, the scavenging pressure rises as the load on the main engine rises, and the cylinder pressure also rises. After time t14, the load on the main engine becomes constant, the scavenging pressure becomes stable, and the in-cylinder pressure also becomes stable.

(When the load of the diesel engine 11 decreases and the turbine capacity decreases and increases)
On the other hand, at time t15, when the load on the main engine is reduced and the scavenging pressure and the in-cylinder pressure are also reduced, at time t16, the control device 13 opens and closes the on-off valve 60 to close the on-off valve 60. When the command signal is output, the opening/closing valve 60 operates toward the closing side, so that the VTI supercharger 12 is switched to the low load operation mode. At this time, the opening/closing valve 60 is gradually closed to reduce the nozzle passage area of the exhaust gas G flowing to the side of the auxiliary exhaust gas flow path 57, the rotational speeds of the turbine 32 and the compressor 31 are increased, and the scavenging pressure is increased. As the pressure rises, the cylinder pressure also rises.

  On the other hand, when outputting the opening/closing command signal for closing the opening/closing valve 60, the control device 13 does not switch from the operation parameter B to the operation parameter A, but at the time t8 after the delay time t+Δt, from the operation parameter B. Switch to operating parameter A. Therefore, from the time t16 to the time t18, the opening timing of the exhaust valve 28, the fuel injection timing by the injector 29, and the time are not changed, and the maximum in-cylinder pressure gradually increases without rapidly increasing.

  After that, when the open/close valve 60 moves to the closed position at time t17, the delay time t+Δt elapses at time t18, so the control device 13 switches from the operation parameter B to the operation parameter A here. When the control device 13 outputs the opening/closing command signal for closing the opening/closing valve 60, if the operating parameter B is switched to the operating parameter A, the opening timing of the exhaust valve 28, the fuel injection timing by the injector 29, and the time are changed. Is changed, the maximum in-cylinder pressure may suddenly increase and overshoot between time t16 and time t17 as indicated by the chain double-dashed line in FIG. Further, if the operation parameter corresponding to the operation mode of the VTI supercharger 12 is not set, the maximum in-cylinder pressure becomes lower than the optimum value for the load in the low load operation mode of the VTI supercharger 12. On the other hand, by switching from the operating parameter B to the operating parameter A in the low load operation mode of the VTI supercharger 12, as shown by the solid line in FIG. The cylinder pressure can be maintained at the optimum value.

  As described above, in the control device for the internal combustion engine of the present embodiment, the diesel engine main body 11, the VTI supercharger 12 including the compressor 31 and the turbine 32 that supply the combustion gas to the diesel engine main body 11, and the in-cylinder An exhaust valve 28 and an injector 29 are provided as operating members that affect the pressure, and the control device 13 controls a plurality of operating parameters A and B that determine the operation amounts of the exhaust valve 28 and the injector 29 according to the capacity of the turbine 32. When the capacity of the turbine 32 is changed, the operating parameters A and B are switched after the elapse of a predetermined delay time t+Δt set in advance.

  Therefore, when the capacity of the turbine 32 of the VTI supercharger 12 is changed, the operation parameters A and B are switched after the lapse of the delay time t+Δt, thereby changing the scavenging pressure and the behavior of the in-cylinder pressure due to the switching of the operation parameters A and B. Is reduced, and the performance of the marine diesel engine 10 can be stabilized.

  In the control device for the internal combustion engine of the present embodiment, the operating parameters A and B are switched after a delay time t+Δt has elapsed since the opening/closing command signal of the opening/closing valve 60 of the VTI supercharger 12 was output. Therefore, the operating parameters A and B can be switched at an appropriate time regardless of the time required to change the turbine capacity.

  In the control device for the internal combustion engine of the present embodiment, when the capacity of the turbine 32 increases, the operating parameters A and B are switched simultaneously with the change of the capacity of the turbine 32, while the capacity of the turbine 32 decreases when the capacity of the turbine 32 decreases. The operating parameters A and B are switched after the delay time t+Δt has elapsed from the time of changing. Therefore, when the capacity of the turbine 32 decreases, the scavenging pressure rises. At this time, the operating parameters A and B are switched after the delay time t+Δt elapses, whereby a rapid increase in the cylinder pressure is suppressed and the marine diesel engine is suppressed. The reliability of the engine 10 can be improved.

  In the control device for the internal combustion engine of the present embodiment, the delay time is set by adding the margin time Δt to the switching time t of the opening/closing valve 60 to set the delay time so that the operating parameter A, after the opening/closing valve 60 is completely moved to the switching position. Since B is switched, it is possible to suppress a rapid increase in the in-cylinder pressure with simple control.

  In the control device for the internal combustion engine of the present embodiment, a scavenging pressure or an in-cylinder pressure measurement/estimation device for measuring or estimating the scavenging pressure or the in-cylinder pressure is provided, and the delay time is set until the scavenging pressure or the in-cylinder pressure reaches a constant value. It's time. Therefore, the operating parameters A and B are switched after waiting for the in-cylinder pressure to stabilize, and a sudden increase in the in-cylinder pressure can be suppressed.

  Further, in the internal combustion engine of the present embodiment, the diesel engine main body 11, the VTI supercharger 12 including the compressor 31 and the turbine 32 that supply the combustion gas to the diesel engine main body 11, and the cylinder pressure are affected. An exhaust valve 28 and an injector 29 as an actuating member to be provided, and a plurality of operating parameters A and B for determining the operation amounts of the exhaust valve 28 and the injector 29 according to the capacity of the turbine 32 are provided to change the capacity of the turbine 32 in advance. The control device 13 is provided to switch the operation parameters A and B after the set predetermined delay time t+Δt has elapsed. Therefore, the behavior of the in-cylinder pressure due to the change of the scavenging pressure and the switching of the operating parameters A and B is reduced, and the performance of the marine diesel engine 10 can be stabilized.

10 Marine diesel engine (internal combustion engine)
11 Diesel engine body (internal combustion engine body)
12 VTI supercharger (supercharger)
13 Control device 21 Cylinder part 22 Piston 24 Scavenging port 25 Scavenging trunk 26 Exhaust port 27 Exhaust manifold 28 Exhaust valve 29 Injector (fuel injection valve)
31 Compressor
32 turbine 41 exhaust valve actuating device 44, 48 on-off valve 53 turbine nozzle 54 main exhaust gas flow path 57 auxiliary exhaust gas flow path 60 on-off valve (switching valve)

Claims (7)

The internal combustion engine body,
A supercharger comprising a compressor connected to the internal combustion engine body to supply combustion gas to the internal combustion engine body, and a variable capacity turbine rotating coaxially with the compressor,
An operating member provided on the internal combustion engine body to influence the cylinder pressure,
Equipped with
A plurality of operating parameters for determining the operating amount of the operating member according to the capacity of the turbine are provided, and the operating parameters are switched after a predetermined delay time set in advance when the capacity of the turbine is changed,
A control device for an internal combustion engine, which is characterized in that:   The control device for an internal combustion engine according to claim 1, wherein the operation parameter is switched after the delay time has elapsed from the time when the command for changing the capacity of the turbine was output.   When the capacity of the turbine is increased, the operating parameters are switched at the same time when the capacity of the turbine is changed.On the other hand, when the capacity of the turbine is decreased, the operation parameters are changed after the delay time has elapsed since the capacity of the turbine was changed. The control device for the internal combustion engine according to claim 1 or 2, wherein the control device is switched over.   The supercharger is provided with a switching valve capable of switching the capacity of the turbine, and the delay time is set by adding a preset margin time to the switching time of the switching valve. The control device for an internal combustion engine according to any one of claims 1 to 3.   A scavenging air pressure or in-cylinder pressure measurement estimating device for measuring or estimating the scavenging air pressure or in-cylinder pressure is provided, and the delay time is a time until the scavenging air pressure or the in-cylinder pressure reaches a constant value. The control device for an internal combustion engine according to any one of claims 1 to 3, which is characterized.   The control device for an internal combustion engine according to any one of claims 1 to 5, wherein the operating member is at least one of an exhaust valve, a fuel injection valve, and a hydraulically operated device. The internal combustion engine body,
A supercharger comprising a compressor connected to the internal combustion engine body to supply combustion gas to the internal combustion engine body, and a variable capacity turbine rotating coaxially with the compressor,
An operating member provided on the internal combustion engine body to influence the cylinder pressure,
A control device that is provided with a plurality of operation parameters that determine the operation amount of the operation member according to the capacity of the turbine, and that switches the operation parameters after a lapse of a predetermined delay time preset when the capacity of the turbine is changed, ,
An internal combustion engine comprising:

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