TWI813751B - Internal combustion engine and control system - Google Patents

Abstract

The exhaust gas discharged from the combustion chamber 20 flows through the exhaust flow passage 42 of the internal combustion engine 1. The reducing agent supply unit supplies the reducing agent to the exhaust flow passage 42 via the nozzle 61 attached to the exhaust flow passage 42 and mixes it with the exhaust gas. The reactor 66 brings the exhaust flowing in from the exhaust flow passage 42 into contact with the catalyst to carry out the NOx removal treatment. The exhaust gas that has passed through the reactor 66 is led to the flue 81. The bypass passage 681 bypasses the reactor 66 and connects the exhaust passage 42 and the flue 81. The bypass valve 682 opens and closes the bypass passage 681. When the valve opening process of the bypass valve 682 is detected, the supply control unit controls the reducing agent supply unit to stop the supply of the reducing agent to the exhaust flow path 42. Thereby, the inflow of the reducing agent to a part downstream of the reactor 66 can be suppressed. A control system is also provided.

Description

Internal combustion engine and control system

The invention relates to an internal combustion engine and a control system.

Previously, in order to reduce nitrogen oxides (ie, _NOx ) contained in the exhaust gas of marine diesel engines, SCR (Selective catalytic reduction: Selective catalytic reduction) denitrification devices were installed on ships. For example, in the exhaust gas denitration device of Japanese Patent Application Laid-Open No. 9-150038 (Document 1), urea water is mixed into the exhaust gas as a reducing agent and sent to the exhaust gas denitration device, thereby reducing the amount of urea in the exhaust gas. Nitrogen oxides are reduced and converted into harmless substances such as nitrogen and water.

In addition, Japanese Patent Application Laid-Open No. 2017-186999 (Document 2) proposes a technology for updating the high-pressure SCR system in a marine engine system. In the marine engine system shown in FIG. 4 , the exhaust gas sent from the combustion chamber to the exhaust collector (receiver) is guided to the turbine of the supercharger via the high-pressure SCR system. In the high-pressure SCR system, first, urea water or the like is supplied as a reducing agent to the exhaust gas sent from the exhaust gas header to the gasification/mixer via the reactor/sealing valve. In the gasification/mixer, the reducing agent is gasified and decomposed into ammonia, which is mixed with the exhaust gas and then directed to the SCR reactor. In the SCR reactor, nitrogen oxides in the exhaust gas are reduced and converted into nitrogen, water, etc. The marine engine system is provided with a bypass flow path that allows the exhaust gas from the exhaust collector to be directed to the turbine without passing through the SCR reactor by closing the reactor seal valve.

However, in the denitration system as described above, if the reducing agent flows into the turbine without passing through the reactor, deposits originating from the reducing agent may be generated inside the turbine. In addition, the deposit may be generated in an exhaust economizer, a flue, etc. located downstream of the turbine. Furthermore, the reducing agent may flow out to the outside through the turbine.

The present invention relates to an internal combustion engine, the object of which is to suppress the inflow of a reducing agent downstream of a reactor. [Technical means to solve problems]

An internal combustion engine according to a preferred aspect of the present invention includes: an exhaust flow path through which exhaust gas flows; and a reducing agent supply unit that supplies a reducing agent to the exhaust flow path through a nozzle attached to the exhaust flow path and interacts with the exhaust flow path. The exhaust gas is mixed; the reactor is used to make the exhaust gas flowing in from the exhaust flow path contact the catalyst to perform denitration treatment; the flue is to guide the exhaust gas passing through the reactor; the bypass flow path is to bypass all The reactor connects the exhaust flow path to the flue; a bypass valve opens and closes the bypass flow path; a turbine is configured between the reactor, the bypass flow path, and the Between the flues, the exhaust gas rotates; the compressor uses the rotation of the turbine as power to pressurize the intake air; and the supply control unit detects the valve opening process of the bypass valve. The reducing agent supply unit controls to stop supplying the reducing agent to the exhaust gas flow path. With the bypass valve closed, exhaust gas passing through the reactor flows into the turbine. With the bypass valve open, the exhaust gas passing through the reactor and the bypass flow path flows into the turbine. According to the internal combustion engine, the inflow of the reducing agent to the downstream side of the reactor can be suppressed.

Preferably, the reducing agent supply unit includes: a reducing agent supply source that stores the reducing agent; a pipe that connects the reducing agent supply source with the nozzle; and a pump that passes from the reducing agent supply source through the nozzle. a piping conveying the reducing agent to the nozzle; and a switching unit provided on the piping to switch the conveying of the reducing agent conveyed by the pump between the nozzle and a structure other than the nozzle. , and when detecting the valve opening process of the bypass valve, the supply control unit controls the switching unit to switch the delivery location of the reducing agent from the nozzle to the other configuration. , thereby stopping the supply of the reducing agent from the nozzle to the exhaust gas flow path.

It is preferable that the other structure is the reducing agent supply source or the pipe located upstream of the switching unit.

Preferably, when the supply control unit detects a stop process of the pump, it controls the switching unit to switch the delivery location of the reducing agent from the nozzle to the other configuration.

Preferably, the reducing agent supply unit further includes a check valve, and the check valve is provided on the pipe near the nozzle between the switching unit and the nozzle.

Preferably, the gas supply unit further includes a gas supply unit for supplying gas to the nozzle, and after the supply of the reducing agent from the nozzle to the exhaust gas flow path is stopped, the supply control unit controls the gas supply unit to control the gas supply unit. The nozzle supplies the gas.

Preferably, the cleaning liquid supply unit further includes a cleaning liquid supply unit for supplying cleaning liquid to the nozzle, and the supply control unit controls the cleaning liquid supply unit after stopping the supply of the reducing agent from the nozzle to the exhaust gas flow path. , thereby supplying the cleaning liquid to the nozzle. The supply of the gas from the gas supply part to the nozzle starts from the time when the cleaning liquid is supplied from the cleaning liquid supply part to the nozzle. Start after the specified time.

Preferably, when the supply control unit detects a valve closing process of the bypass valve in an open state of the bypass valve, it is preferable to stop supply from the cleaning liquid supply unit to the nozzle after a predetermined time has elapsed. The cleaning fluid.

Preferably, the reducing agent supply unit includes: a reducing agent supply source that stores the reducing agent; a pipe that connects the reducing agent supply source with the nozzle; and a pump that passes from the reducing agent supply source through the nozzle. The pipe transports the reducing agent to the nozzle, and when the supply control unit detects the valve opening process of the bypass valve, it stops the operation of the pump, thereby stopping the flow of the reducing agent from the nozzle to the nozzle. The exhaust flow path supplies the reducing agent.

The invention also relates to a control system. The control system according to a preferred aspect of the present invention controls the reducing agent supply unit in the internal combustion engine. The internal combustion engine includes: an exhaust flow path through which exhaust gas flows; a reducing agent supply unit that supplies a reducing agent to the exhaust flow path through a nozzle installed in the exhaust flow path and mixes it with the exhaust gas; and a reaction. The exhaust gas flowing in from the exhaust flow path is brought into contact with the catalyst to perform denitration treatment; the flue is used to guide the exhaust gas passing through the reactor; the bypass flow path is used to bypass the reactor and transfer all the exhaust gas to the reactor. The exhaust flow path is connected to the flue; a bypass valve opens and closes the bypass flow path; a turbine is configured between the reactor, the bypass flow path, and the flue, It is rotated by the exhaust gas; and a compressor uses the rotation of the turbine as power to pressurize the intake air. With the bypass valve closed, exhaust gas passing through the reactor flows into the turbine. With the bypass valve open, the exhaust gas passing through the reactor and the bypass flow path flows into the turbine. The control system includes: a detection unit that detects the valve opening process of the bypass valve; and a supply control unit that supplies the reducing agent when the detection unit detects the valve opening process of the bypass valve. The control unit performs control to stop the supply of the reducing agent to the exhaust gas flow path. According to the control system, the inflow of the reducing agent to the downstream side of the reactor can be suppressed.

The above object and other objects, features, aspects and advantages will be clarified by the following detailed description of the invention with reference to the accompanying drawings.

FIG. 1 is a diagram showing the structure of an internal combustion engine 1 according to the first embodiment of the present invention. The internal combustion engine 1 is, for example, a diesel engine. In the example shown in FIG. 1 , the internal combustion engine 1 is a two-stroke engine used as a main engine of a ship.

The internal combustion engine 1 includes a cylinder 2, a piston 3, a scavenging flow path 41, an exhaust flow path 42, an air cooler 43, a supercharger 5, a denitration system 6, and a flue 81. The cylinder 2 is a covered, substantially cylindrical member centered on a central axis extending in the vertical direction in FIG. 1 . The piston 3 is a substantially cylindrical member centered on the central axis, and its upper part is arranged inside the cylinder 2 . The piston 3 can move in the up and down direction. Furthermore, the up-down direction in Figure 1 does not necessarily need to be parallel to the direction of gravity.

The cylinder 2 includes a cylinder liner 21 , a cylinder head 22 and an exhaust valve 25 . The cylinder liner 21 is a substantially cylindrical member centered on the central axis. The cylinder head 22 is a covered, substantially cylindrical member that is attached to the upper portion of the cylinder liner 21 . An exhaust port 24 is formed in the top cover portion of the cylinder head 22 . The exhaust port 24 is connected to the exhaust flow path 42 . The exhaust port 24 is opened and closed by an exhaust valve 25 . As shown by the solid line in FIG. 1 , the exhaust valve 25 is separated downward from the exhaust port 24 and the exhaust port 24 is opened. In addition, as shown by the two-dot chain line in FIG. 1 , the exhaust valve 25 contacts the cylinder head 22 and overlaps the exhaust port 24 , so that the exhaust port 24 is closed. A scavenging port 23 is provided near the lower end of the cylinder liner 21 . The scavenging port 23 is a collection of a plurality of through holes formed in a circumferential array on the side surface of the cylinder liner 21 . The scavenging port 23 is connected to the scavenging flow path 41 .

The piston 3 has a piston head 31 and a piston rod 32 . The piston head 31 is a thick, substantially disc-shaped portion centered on the central axis. The piston head 31 is arranged inside the cylinder liner 21 . The piston rod 32 is a substantially cylindrical portion extending downward from the lower surface of the piston head 31 . The lower end of the piston rod 32 is connected to a crank mechanism (not shown). The crank mechanism causes the piston 3 to reciprocate in the up and down direction. In FIG. 1 , the piston 3 located at the bottom dead center of the reciprocating movement is depicted by a solid line, and the piston 3 located at the top dead center is depicted by a two-dot chain line.

In the internal combustion engine 1 , the space surrounded by the cylinder liner 21 , the cylinder head 22 , the exhaust valve 25 and the upper surface of the piston head 31 (that is, the upper surface of the piston 3 ) is a combustion chamber 20 for burning fuel and air. .

Scavenging air is supplied to the combustion chamber 20 from the scavenging air flow path 41 via the scavenging port 23 . The scavenging flow path 41 includes a scavenging chamber 411 and a scavenging collector 412 . The scavenging chamber 411 is a space (that is, a scavenging piping) provided around the scavenging port 23 of the cylinder liner 21 . The scavenging port 23 communicates with the scavenging collector 412 via the scavenging chamber 411 . The scavenging air collector 412 is a large, substantially cylindrical container that supplies scavenging air to the scavenging chamber 411 .

Gas generated by the combustion of fuel and air in the combustion chamber 20 (that is, combustion gas) is discharged to the exhaust flow path 42 through the exhaust port 24 . The exhaust flow path 42 is a pipe through which gas discharged from the combustion chamber 20 (hereinafter referred to as “exhaust gas”) flows. The exhaust flow path 42 includes an exhaust pipe 421 and an exhaust collector 422 . The exhaust pipe 421 is a pipe that connects the exhaust port 24 and the exhaust collector 422 . The exhaust gas collector 422 is a substantially cylindrical large container that receives the exhaust gas from the combustion chamber 20 . Furthermore, the combustion chamber 20 can also be understood as a part of the exhaust gas flow path 42 through which exhaust gas flows.

In the internal combustion engine 1, multiple sets of cylinders 2 and pistons 3 are provided. As shown in FIG. 2, multiple combustion chambers 20 are connected to a scavenging collector 412 and an exhaust collector 422. That is, the scavenging collector 412 is a scavenging manifold for distributing and supplying scavenging gas to the plurality of combustion chambers 20 . In addition, the exhaust collector 422 is an exhaust manifold (also referred to as an exhaust manifold) that collects exhaust gas discharged from the plurality of combustion chambers 20 . Since the exhaust gases from the plurality of combustion chambers 20 are sequentially sent to the exhaust gas collector 422 at different timings, a turbulent flow of exhaust gas is formed in the exhaust gas collector 422 .

The exhaust gas collected in the exhaust collector 422 is denitrated by the denitration system 6 shown in FIG. 1 and then sent to the supercharger 5 . The denitration process using the denitration system 6 will be described later. The supercharger 5 is a turbocharger including a turbine 51 and a compressor 52 . In the supercharger 5, the exhaust gas is used to pressurize the intake air to generate scavenging air.

Specifically, the turbine 51 is rotated by the exhaust gas sent from the exhaust collector 422 to the supercharger 5 . The exhaust gas used for the rotation of the turbine 51 is guided to the flue 81 and discharged from the flue 81 to the outside of the internal combustion engine 1 . The compressor 52 uses the rotational force generated by the turbine 51 (that is, uses the rotation of the turbine 51 as motive power) to pressurize and compress the intake air (air) taken in from the outside of the internal combustion engine 1 through the intake path 82 . The pressurized air (ie, the scavenging air) is cooled by the air cooler 43 and then supplied to the scavenging collector 412 , and is supplied from the scavenging collector 412 to each combustion chamber 20 .

FIG. 3 is a diagram showing a part of the structure of the denitration system 6 . In FIG. 3 , structures other than the denitration system 6 are also shown. As shown in FIGS. 1 and 3 , the denitration system 6 includes a nozzle 61 , a common pipe 62 , a reducing agent supply part 63 , a cleaning liquid supply part 64 , a gas supply part 65 , a reactor 66 , an SCR flow path 67 , and a bypass. Flow path 681, bypass valve 682, and control system 70.

The control system 70 is, for example, a programmable logic controller (Programmable Logic Controller, PLC). The PLC includes: a processor, a memory, an input and output unit, and a bus. The bus is a signal circuit that connects the processor, memory, and input and output units. The memory stores programs and various information. The processor executes various processes (for example, numerical operations, etc.) while using the memory and the like based on the program etc. stored in the memory. The input/output unit receives input from the operator and signal input from other devices, and outputs the signal to the other device. The PLC performs processing based on a predetermined program, thereby realizing each function of the control system 70 (for example, the detection unit 71 and the supply control unit 72). The detection unit 71 is mainly realized by a processor, and detects the valve opening process and the valve closing process of the bypass valve 682 described later. The supply control unit 72 is mainly implemented by a processor, and controls the reducing agent supply unit 63 and the like. The control system 70 may be a general computer system including a keyboard, a display, etc., or may be a circuit board or the like. Furthermore, the control system 70 is omitted from the illustration in FIG. 1 .

The nozzle 61 is attached to the exhaust collector 422 in the exhaust flow path 42 . The nozzle 61 is connected to the reducing agent supply part 63, the cleaning liquid supply part 64, and the gas supply part 65 via a common pipe 62. The reducing agent supply part 63 , the cleaning liquid supply part 64 , and the gas supply part 65 are controlled by the supply control part 72 of the control system 70 . The reducing agent supply unit 63 is driven when denitration processing of exhaust gas is performed. The cleaning liquid supply part 64 and the gas supply part 65 are driven when the denitration process is stopped, and are used for cleaning the nozzle 61 and the like.

The reducing agent supply unit 63 supplies the reducing agent used for denitration processing of exhaust gas to the nozzle 61 . As the reducing agent, urea water (CO(NH ₂ ) ₂ ), ammonia water (NH ₃ ), etc. can be used. In this embodiment, urea water is used as the reducing agent. The reducing agent supply unit 63 includes a reducing agent supply source 631, a reducing agent pipe 632, a reducing agent pump 633, a switching unit 634, a check valve 635, and a circulation channel 636. The reducing agent supply source 631 is, for example, a storage tank that stores reducing agent. The reducing agent pipe 632 is a pipe that connects the reducing agent supply source 631 and the nozzle 61 . The reducing agent pump 633 is a pump that delivers the reducing agent from the reducing agent supply source 631 to the nozzle 61 via the reducing agent pipe 632 . The flow rate of the reducing agent delivered to the nozzle 61 by the reducing agent pump 633 is, for example, several liters/hour to several hundred liters/hour. The reducing agent pump 633 is, for example, a variable frequency pump.

The switching unit 634 is provided in the reducing agent pipe 632 between the reducing agent pump 633 and the nozzle 61 . The switching unit 634 is, for example, a solenoid valve. One end of the circulation flow path 636 is connected to the switching part 634 . The other end of the circulation flow path 636 is connected to the reducing agent supply source 631 . The other end of the circulation flow path 636 may be connected to the reducing agent pipe 632 between the reducing agent supply source 631 and the reducing agent pump 633 or between the reducing agent pump 633 and the switching unit 634. In other words, the other end of the circulation flow path 636 may be connected to the reducing agent pipe 632 on the upstream side of the switching unit 634 .

In the state shown in FIG. 3 , the reducing agent sent from the reducing agent pump 633 to the switching unit 634 is supplied to the nozzle 61 via the switching unit 634 , the reducing agent pipe 632 , the check valve 635 and the common pipe 62 . The reducing agent does not flow from the switching unit 634 to the circulation flow path 636 . On the other hand, when the switching unit 634 is switched, the reducing agent sent from the reducing agent pump 633 to the switching unit 634 is not supplied to the nozzle 61 but is circulated to the reducing agent supply source 631 (or the reducing agent pipe 632) via the circulation flow path 636. . In other words, the switching unit 634 switches the delivery location of the reducing agent delivered by the reducing agent pump 633 between the nozzle 61 and other structures other than the nozzle 61 (that is, the reducing agent supply source 631 or the reducing agent pipe 632).

The check valve 635 is provided in the reducing agent pipe 632 near the nozzle 61 between the nozzle 61 and the switching part 634 . Specifically, the check valve 635 is disposed between the merging point of the reducing agent pipe 632 and the common piping 62 and the switching unit 634 in the vicinity of the merging point. The check valve 635 prevents fluid from flowing backward from the merging point side to the switching part 634 .

The cleaning liquid supply unit 64 supplies the cleaning liquid used for cleaning the nozzle 61 to the nozzle 61 . As the cleaning fluid, clean water used for other purposes in ships, etc. can be used. Furthermore, liquids other than clean water can also be used as the cleaning liquid. The cleaning liquid supply unit 64 includes a cleaning liquid supply source 641, a cleaning liquid pipe 642, a cleaning liquid pump 643, and a check valve 645. The cleaning liquid supply source 641 is, for example, a storage tank that stores cleaning liquid. The cleaning liquid pipe 642 is a pipe that connects the cleaning liquid supply source 641 and the nozzle 61 . The cleaning liquid pump 643 is a pump that delivers the cleaning liquid from the cleaning liquid supply source 641 to the nozzle 61 via the cleaning liquid pipe 642 .

The check valve 645 is provided in the cleaning fluid pipe 642 near the nozzle 61 between the nozzle 61 and the cleaning fluid pump 643 . Specifically, the check valve 645 is disposed between the merging point of the cleaning liquid pipe 642 and the common piping 62 and the cleaning liquid pump 643 in the vicinity of the merging point. The check valve 645 prevents fluid from flowing backward from the merging point side to the cleaning liquid pump 643 .

The gas supply unit 65 supplies gas to the nozzle 61 for cleaning the nozzle 61 and for promoting the delivery of exhaust gas from the exhaust gas collector 422 . As the gas, compressed air (for example, air with a pressure of several hundred kPa to several MPa) or the like can be used. Furthermore, gas other than compressed air may be supplied from the gas supply part 65 to the nozzle 61 . The gas supply unit 65 includes a gas supply source 651, a gas pipe 652, a gas supply valve 653, and a check valve 655. The gas supply source 651 is, for example, a storage tank that stores compressed air. The gas pipe 652 is a pipe that connects the gas supply source 651 and the nozzle 61 . The gas supply valve 653 is provided on the gas pipe 652, and the gas from the gas supply source 651 is supplied to the nozzle 61 by opening the valve. In addition, by closing the gas supply valve 653, the gas supply to the nozzle 61 is stopped. Furthermore, instead of the gas supply source 651 and the gas supply valve 653, a blower that compresses and delivers air may be provided.

The check valve 655 is provided on the gas pipe 652 near the nozzle 61 between the nozzle 61 and the gas supply valve 653 . Specifically, the check valve 655 is disposed between the merging point of the gas pipe 652 and the common piping 62 and the gas supply valve 653 in the vicinity of the merging point. The check valve 655 prevents fluid from flowing backward from the merging point side to the gas supply valve 653 and the gas supply source 651 .

The SCR flow path 67 is a pipe that connects the exhaust collector 422 of the exhaust flow path 42 and the turbine 51 of the supercharger 5 . A reactor 66 is provided on the SCR flow path 67 . The reactor 66 contains a catalyst used for denitration treatment of exhaust gas. In the reactor 66, denitration treatment of the exhaust gas is performed using the SCR (Selective catalytic reduction) method.

The bypass flow path 681 is a pipe branched from the SCR flow path 67 in the middle and bypasses the reactor 66 to merge with the SCR flow path 67 . In other words, the bypass flow path 681 connects the exhaust gas collector 422 of the exhaust gas flow path 42 to the turbine 51 and flue 81 of the supercharger 5 while bypassing the reactor. Specifically, the bypass flow path 681 branches from the SCR flow path 67 between the exhaust collector 422 and the reactor 66 , and merges with the SCR flow path 67 between the reactor 66 and the turbine 51 . The bypass valve 682 is provided on the bypass flow path 681 and is used to open and close the bypass flow path 681 . The bypass valve 682 is driven by, for example, a drive control unit (not shown) of the internal combustion engine 1 .

When the denitration process of the exhaust gas is being performed in the denitration system 6, as shown in FIG. 4, the reducing agent pump 633 is connected to the nozzle 61 through the switching part 634 of the reducing agent supply part 63, and the reducing agent pump 633 is connected to the nozzle 61. The reducing agent supplied from the reducing agent supply source 631 is continuously supplied to the exhaust collector 422 via the switching unit 634 , the reducing agent pipe 632 , the check valve 635 , the common pipe 62 and the nozzle 61 . Spray gas is supplied to the nozzle 61 from a spray gas supply unit (not shown), and the reducing agent from the nozzle 61 is supplied into the exhaust collector 422 in a state of being atomized by the spray gas (that is, in a mist state). The supply amount of the reducing agent is controlled based on the nitrogen oxide content in the exhaust gas and the like. Furthermore, while the reducing agent is being supplied to the nozzle 61, the cleaning liquid pump 643 of the cleaning liquid supply unit 64 is stopped. In addition, since the gas supply valve 653 of the gas supply unit 65 is closed, the cleaning liquid and compressed air are not supplied to the nozzle 61. Nozzle 61. In FIG. 4 , the path in which the reducing agent flows is drawn with a solid line, and the other path in which the fluid does not flow is drawn with a broken line (the same is true in FIG. 8 ).

The reducing agent (ie, urea water) supplied from the nozzle 61 to the exhaust gas collector 422 is mixed with the exhaust gas. As described above, in the exhaust collector 422, the exhaust gas from each exhaust pipe 421 flows in to form a turbulent flow of the exhaust gas, so that the reducing agent and the exhaust gas are mixed efficiently. In the exhaust collector 422, urea mixed with the high-temperature exhaust gas is thermally decomposed to generate ammonia and isocyanic acid (HNCO). In addition, isocyanic acid is hydrolyzed, thereby generating ammonia. The exhaust gas mixed with ammonia is sent from the exhaust gas collector 422 to the SCR flow path 67 .

While the denitration process of the exhaust gas is being performed, the bypass valve 682 is closed. Therefore, as shown in FIG. 5 , the exhaust gas sent from the exhaust collector 422 to the SCR flow path 67 (that is, the exhaust gas containing ammonia) flows in. to reactor 66 and contacted with the catalyst. As a result, nitrogen oxides (NO _x ) in the exhaust gas react with ammonia and are reduced, and decomposed into nitrogen (N ₂ ) and water (H ₂ O). The denitrated exhaust gas that has passed through the reactor 66 is supplied to the turbine 51 disposed between the reactor 66 and the flue 81 via the SCR flow path 67 . The turbine 51 is rotated using the exhaust gas from the reactor 66 . The exhaust gas passing through the turbine 51 is guided to the flue 81 and discharged from the flue 81 to the outside of the internal combustion engine 1 . In addition, in FIG. 5 , a path through which the exhaust gas does not flow (that is, the bypass flow path 681 ) is drawn with a dotted line.

On the other hand, when the bypass valve 682 is opened, as shown in FIG. 6 , the exhaust gas sent from the exhaust collector 422 to the SCR flow path 67 flows through the reactor 66 and the bypass flow path 681 and is supplied to the reactor. 66 and the turbine 51 between the bypass flow path 681 and the flue 81. In other words, the exhaust gas that has passed through the reactor 66 and the exhaust gas that has passed through the bypass flow path 681 without flowing into the reactor 66 (that is, bypassing the reactor 66 ) flow into the turbine 51 . The turbine 51 rotates using the exhaust gas from the reactor 66 and the bypass flow path 681 . The exhaust gas passing through the turbine 51 is guided to the flue 81 and discharged from the flue 81 to the outside of the internal combustion engine 1 .

The bypass valve 682 is opened, for example, when the temperature of the exhaust gas at the inlet of the turbine 51 is insufficient when the ship is accelerating. Specifically, for example, the drive control unit obtains the exhaust gas temperature at the inlet of the SCR flow path 67 and the exhaust gas temperature at the turbine 51 inlet, and when the difference between the two temperatures is greater than or equal to a predetermined threshold value, The bypass valve 682 is opened by the drive control unit. When the bypass valve 682 is open, the exhaust gas passing through the bypass flow path 681 flows into the turbine 51 , so the exhaust gas temperature at the inlet of the turbine 51 can be increased.

In the internal combustion engine 1 , in order to prevent the reducing agent from flowing into the turbine 51 without passing through the reactor 66 while the bypass valve 682 is open, the supply of the reducing agent from the nozzle 61 to the exhaust collector 422 is stopped. When the reducing agent flows into the turbine 51 , solid matter derived from the reducing agent may be generated and accumulated in the turbine 51 due to temperature conditions and the like. In addition, ammonia generated from urea may be released from the flue 81 to the outside of the internal combustion engine 1 (that is, ammonia loss may occur).

Hereinafter, the flow of stopping the supply of the reducing agent will be described with reference to FIG. 7 . First, when the drive control unit determines that the bypass valve 682 in the closed state needs to be opened, the valve opening process of the bypass valve 682 is started (step S11 ). Specifically, a valve opening command (also referred to as a valve opening signal) is issued from the drive control unit to the pneumatic actuator that is a driving unit of the bypass valve 682 . Then, the pressure inside the pneumatic actuator rises, and after a predetermined time has elapsed since the valve opening command was issued, the bypass valve 682 opens with a predetermined opening degree. The predetermined time is a time lag required for driving the so-called bypass valve 682, and is, for example, approximately 3 seconds. In the internal combustion engine 1, during the time lag period, steps S12 to S15 described below are executed.

The detection unit 71 of the control system 70 continues to monitor the valve opening process and the valve closing process of the bypass valve 682 . When the detection unit 71 detects the valve opening process of the bypass valve 682, it sends a signal to the supply control unit 72 to notify the start of the valve opening process. When the detection unit 71 detects the valve opening process of the bypass valve 682 , the supply control unit 72 controls the reducing agent supply unit 63 to stop the supply of the reducing agent from the nozzle 61 to the exhaust collector 422 (step S12 ).

Specifically, the detection unit 71 detects the valve opening command sent from the drive control unit to the bypass valve 682 and detects the start of the valve opening process of the bypass valve 682 . Then, the supply control unit 72 controls the switching unit 634 of the reducing agent supply unit 63 to block the connection between the reducing agent pump 633 and the nozzle 61 and connect the reducing agent pump 633 to the circulation flow path 636 as shown in FIG. 8 . Since the reducing agent pump 633 continues to operate, the reducing agent transported from the reducing agent supply source 631 by the reducing agent pump 633 returns to the reducing agent supply source 631 (or the reducing agent pipe 632 upstream of the switching unit 634) via the circulation flow path 636. . In other words, the reducing agent sent from the reducing agent pump 633 is not supplied to the nozzle 61 but circulates in the reducing agent supply part 63 . In addition, the operation of the reducing agent pump 633 continues from step S11 to step S20 (described later).

In this way, the supply control unit 72 switches the delivery location of the reducing agent delivered from the reducing agent pump 633 from the nozzle 61 to another structure other than the nozzle 61 (that is, the reducing agent supply source 631 or the reducing agent pipe 632), thereby stopping the delivery of the reducing agent from the nozzle 61. The nozzle 61 supplies the reducing agent to the exhaust collector 422 . Furthermore, the detection unit 71 can detect the start of the valve opening process of the bypass valve 682 by detecting a pressure change inside the pneumatic actuator that is a driving unit of the bypass valve 682 . In this case, the detection unit 71 may include a sensor that measures the pressure inside the pneumatic actuator and/or a receiving unit that receives a measurement value measured by the sensor. In addition, the driving part of the bypass valve 682 may be a mechanism other than a pneumatic actuator (for example, a hydraulic actuator or an electric actuator).

When the supply of the reducing agent from the nozzle 61 to the exhaust collector 422 is stopped, the supply control unit 72 controls the cleaning liquid supply unit 64 to start supplying the cleaning liquid such as clean water to the nozzle 61 (step S13 ). Specifically, the supply control unit 72 drives the cleaning liquid pump 643 of the cleaning liquid supply unit 64 to transport the cleaning liquid from the cleaning liquid supply source 641 to the nozzle 61 . The cleaning liquid is sprayed from the nozzle 61 together with the reducing agent remaining in the common pipe 62 and the nozzle 61 , and is supplied to the exhaust collector 422 in a state of being atomized by the spray gas. Thereby, the reducing agent remaining inside the common pipe 62 and the nozzle 61 is flushed and replaced with a cleaning liquid. In this way, by cleaning the common pipe 62 and the nozzle 61 , it is possible to prevent or suppress solid matter derived from the reducing agent from accumulating in the common pipe 62 or the nozzle 61 and clogging the nozzle 61 .

Next, the supply control unit 72 controls the gas supply unit 65 to start supplying gas such as compressed air to the nozzle 61 (step S14 ). Specifically, the supply control unit 72 opens the gas supply valve 653 of the gas supply unit 65 and supplies the gas to the nozzle 61 via the common pipe 62 . At this time, the cleaning liquid is continued to be supplied from the cleaning liquid supply part 64 to the nozzle 61 , and the gas is injected into the exhaust collector 422 from the nozzle 61 together with the cleaning liquid. Thereby, the common pipe 62 and the nozzle 61 are further cleaned, and the reducing agent in the common pipe 62 and the nozzle 61 is almost completely removed. That is, the gas supplied from the gas supply part 65 to the nozzle 61 is a flushing gas for discharging the reducing agent from the nozzle 61 .

Preferably, the gas supply from the gas supply unit 65 to the nozzle 61 starts after a predetermined time (for example, about 1 second) has elapsed since the cleaning liquid supply unit 64 starts supplying the cleaning liquid to the nozzle 61 (step S13). . Before the gas is supplied to the common pipe 62 and the nozzle 61 , the reducing agent in the common pipe 62 and the nozzle 61 is flushed by the cleaning liquid to a certain extent (that is, the reducing agent is diluted with the cleaning liquid), thereby preventing the reducing agent from remaining in the common pipe 62 The reducing agent in the nozzle 61 is discharged in a large amount into the exhaust collector 422 in a very short time by the gas from the gas supply part 65 (that is, an excess supply of the reducing agent). The time difference between the start of cleaning liquid supply and the start of gas supply is realized by a delay timer, for example.

After a predetermined time (for example, approximately 2 seconds) elapses from the start of gas supply in step S14 , the gas supply valve 653 is closed to stop the supply of gas from the gas supply unit 65 to the nozzle 61 (step S15 ). The supply of gas from the gas supply unit 65 to the nozzle 61 is completed before the valve opening process of the bypass valve 682 is completed and the bypass valve 682 is actually opened (step S16 ). Alternatively, the supply of gas from the gas supply unit 65 may be stopped (step S15 ) at the same time as the valve opening process of the bypass valve 682 is completed (step S16 ). In other words, as described above, steps S14 and S15 are performed during the time lag (for example, about 3 seconds) from when the valve opening command of the bypass valve 682 is issued to when the bypass valve 682 is actually opened. This allows the reducing agent in the nozzle 61 to be pushed out to the exhaust collector 422 before the bypass valve 682 is actually opened, and the exhaust gas flowing in from each exhaust pipe 421 can reduce the reducing agent in the exhaust collector 422 . The agent is pushed out to the SCR flow path 67.

After a predetermined time (for example, 15 seconds) elapses after the gas supply from the gas supply unit 65 is stopped, the driving of the cleaning liquid pump 643 is stopped, and the supply of cleaning liquid from the cleaning liquid supply unit 64 to the nozzle 61 is stopped (step S17 ). Thereafter, while the bypass valve 682 is in the open state, the reducing agent, cleaning liquid, and gas are not supplied from the nozzle 61 to the exhaust collector 422 .

Then, when the drive control unit determines that it is necessary to close the bypass valve 682 in the open state, the valve closing process of the bypass valve 682 is started (step S18 ). Specifically, a valve closing command (also referred to as a valve closing signal) is issued from the drive control unit to the driving unit of the bypass valve 682 . The bypass valve 682 is closed after a predetermined time (ie, time lag) has elapsed since the valve closing command was issued. In other words, the valve closing process of the bypass valve 682 ends (step S19).

When the detection unit 71 detects the valve closing command of the bypass valve 682 , the supply control unit 72 controls the reducing agent supply unit 63 to restart after a predetermined time (for example, about 10 seconds) has elapsed since the valve closing process was detected. The reducing agent is supplied to the nozzle 61 (step S20). Specifically, the switching unit 634 switches from the state shown in FIG. 8 to the state shown in FIG. 4 , and switches the place where the reducing agent is transported from the reducing agent pump 633 from the reducing agent supply source 631 (or the reducing agent pipe 632 ). Nozzle 61.

The predetermined time is set so that the supply of the reducing agent to the nozzle 61 starts after the bypass valve 682 is actually closed (that is, after the time lag has elapsed). This prevents the reducing agent from being supplied to the exhaust collector 422 while the bypass valve 682 is not yet closed. As a result, the exhaust gas containing the reducing agent and the like is suppressed from flowing into the turbine 51 and the flue 81 via the bypass flow path 681 . Furthermore, the detection unit 71 can detect the start of the valve closing process of the bypass valve 682 by detecting a pressure change inside a pneumatic actuator or the like that is a driving unit of the bypass valve 682 . In addition, the time difference between the detection of the valve closing process and the start of supply of the reducing agent is realized by a delay timer, for example.

As described above, the internal combustion engine 1 includes the exhaust flow path 42, the reducing agent supply part 63, the reactor 66, the flue 81, the bypass flow path 681, the bypass valve 682, the turbine 51, the compressor 52, and the supply Control unit 72. In the exhaust flow path 42, exhaust gas flows. The reducing agent supply part 63 supplies the reducing agent to the exhaust flow path 42 via the nozzle 61 attached to the exhaust flow path 42 and mixes it with the exhaust gas. The reactor 66 brings the exhaust gas flowing in from the exhaust gas flow path 42 into contact with the catalyst to perform denitration processing. Exhaust gas passing through reactor 66 is directed to flue 81 . The bypass flow path 681 bypasses the reactor 66 and connects the exhaust flow path 42 to the flue 81 . The bypass valve 682 opens and closes the bypass flow path 681. The turbine 51 is disposed between the reactor 66, the bypass flow path 681, and the flue 81, and rotates using exhaust gas. The compressor 52 uses the rotation of the turbine 51 as power to pressurize the intake air. When detecting the valve opening process of the bypass valve 682 , the supply control unit 72 controls the reducing agent supply unit 63 to stop the supply of the reducing agent to the exhaust flow path 42 . With the bypass valve 682 closed, the exhaust gas passing through the reactor 66 flows into the turbine 51 . With the bypass valve 682 open, the exhaust gas passing through the reactor 66 and the bypass flow path 681 flows into the turbine 51 .

In the internal combustion engine 1 , the inflow of the reducing agent to the downstream side of the reactor 66 can be suppressed. Specifically, the reducing agent can be suppressed from flowing into the turbine 51 and the flue 81 located downstream of the reactor 66 in the flow of the exhaust gas. As a result, it is possible to prevent or suppress the generation of deposits originating from the reducing agent in the turbine 51 and the flue 81 which are downstream devices of the reactor 66 . In addition, leakage of the reducing agent to the outside of the internal combustion engine 1 can also be prevented or suppressed.

As described above, the reducing agent supply unit 63 preferably includes a reducing agent supply source 631, a reducing agent pipe 632, a reducing agent pump 633, and a switching unit 634. The reducing agent supply source 631 stores reducing agent. The reducing agent pipe 632 is a pipe that connects the reducing agent supply source 631 and the nozzle 61 . The reducing agent pump 633 delivers the reducing agent from the reducing agent supply source 631 to the nozzle 61 via the reducing agent pipe 632 . The switching unit 634 is provided in the reducing agent pipe 632 . The switching unit 634 switches the delivery location of the reducing agent delivered by the reducing agent pump 633 between the nozzle 61 and a configuration other than the nozzle 61 . When the supply control unit 72 detects the valve opening process of the bypass valve 682, it controls the switching unit 634 to switch the delivery location of the reducing agent from the nozzle 61 to the other configuration, thereby stopping the exhaust gas from the nozzle 61. The flow path 42 supplies the reducing agent.

Accordingly, the supply of the reducing agent to the exhaust gas flow path 42 can be stopped without stopping the reducing agent pump 633 . As a result, when the supply of the reducing agent to the exhaust gas flow path 42 is stopped, the control of the denitration system 6 can be simplified. In addition, since the reducing agent pump 633 can be prevented from being repeatedly started, the life of the reducing agent pump 633 can be extended. In addition, the nozzle 61 can be understood as a part of the reducing agent supply part 63 .

More preferably, the other components described above are the reducing agent supply source 631 or the reducing agent pipe 632 upstream of the switching unit 634 . Thereby, when the supply of the reducing agent to the exhaust gas flow path 42 is stopped, the reducing agent transported from the reducing agent pump 633 can be circulated in the reducing agent supply part 63 . As a result, compared with the case where the reducing agent transported from the reducing agent pump 633 is discarded (that is, compared with the case where the other configuration is a drain pipe), the usage amount of the reducing agent in the internal combustion engine 1 can be reduced.

As mentioned above, it is preferable that the internal combustion engine 1 further includes the gas supply part 65 . The gas supply unit 65 supplies gas to the nozzle 61 . In the internal combustion engine 1 , after the supply of the reducing agent from the nozzle 61 to the exhaust flow path 42 is stopped, the supply control unit 72 controls the gas supply unit 65 to supply the gas to the nozzle 61 .

This allows the nozzle 61 after the supply of the reducing agent to be stopped to be appropriately cleaned (that is, cleaning processing). As a result, clogging of the nozzle 61 due to accumulation of solid matter derived from the reducing agent or the like can be prevented or suppressed.

As mentioned above, it is preferable that the internal combustion engine 1 further includes a cleaning fluid supply part 64 . The cleaning liquid supply part 64 supplies cleaning liquid to the nozzle 61 . In the internal combustion engine 1 , after the supply of the reducing agent from the nozzle 61 to the exhaust flow path 42 is stopped, the supply control unit 72 controls the cleaning liquid supply unit 64 to supply the cleaning liquid to the nozzle 61 . Preferably, the gas supply from the gas supply unit 65 to the nozzle 61 starts after a predetermined time has elapsed since the cleaning liquid supply unit 64 starts supplying the cleaning liquid to the nozzle 61 . This can prevent the reducing agent remaining in the nozzle 61 from being discharged into the exhaust collector 422 in a very short period of time by the gas (that is, excessive supply of the reducing agent). As a result, it is possible to suppress the reducing agent and the like from passing through the reactor 66 in an unreacted state and flowing into the turbine 51 and the flue 81 .

As mentioned above, it is preferable that the reducing agent supply part 63 further includes the check valve 635 . The check valve 635 is provided in the reducing agent pipe 632 near the nozzle 61 between the switching part 634 and the nozzle 61 . This can prevent the fluid from flowing back from the nozzle 61 side to the switching unit 634 . In addition, when the cleaning liquid supply part 64 and the gas supply part 65 are used to clean the nozzle 61, by arranging the check valve 635 near the nozzle 61, the amount of reducing agent that needs to be flushed during cleaning can be reduced (i.e., The amount of reducing agent remaining between the nozzle 61 and the check valve 635). As a result, the time required for cleaning the nozzle 61 can be shortened, and the reducing agent in the nozzle 61 can be pushed out to the exhaust collector 422 before the bypass valve 682 is actually opened, and can be passed through the exhaust pipe 421 flowing in. The exhaust gas pushes the reducing agent in the exhaust gas collector 422 to the SCR flow path 67 . The piping length from the check valve 635 to the nozzle 61 is preferably within 3 m, more preferably within 2 m.

As described above, it is preferable that the exhaust gas flow path 42 includes the exhaust gas collector 422 that collects the exhaust gas exhausted from the combustion chamber 20 and the exhaust gas exhausted from other combustion chambers 20, and collects the exhaust gas exhausted from the nozzle. 61 supplies the reducing agent to the exhaust collector 422. This makes it possible to efficiently mix the reducing agent and the exhaust gas by utilizing the turbulent flow formed in the exhaust gas collector 422 due to the exhaust gas being sequentially transported from the plurality of combustion chambers 20 . As a result, the denitration process using the exhaust gas of the denitration system 6 can be appropriately performed.

In the internal combustion engine 1 , the opening and closing of the bypass valve 682 may be repeated in a short period of time due to load fluctuations of the internal combustion engine 1 due to the influence of ocean phenomena. For example, there is a possibility that immediately after the valve opening process of the bypass valve 682 ends in step S16 (for example, a few seconds later), the valve closing process of the bypass valve 682 starts (step S18). After the valve closing process of 682 is completed, the valve opening process of the bypass valve 682 is also started immediately (for example, several seconds later) (step S11).

In the internal combustion engine 1 , when the supply control unit 72 detects the valve closing process of the bypass valve 682 while the bypass valve 682 is open, it stops supplying the cleaning liquid from the cleaning liquid supply unit 64 to the nozzle 61 after a predetermined time has elapsed. Therefore, when the valve opening process of the temporarily closed bypass valve 682 is restarted before the predetermined time (for example, about 10 seconds) elapses, since the cleaning liquid supply unit 64 continues to supply the nozzle 61 Therefore, the nozzle 61 can be cleaned without changing the operation of the cleaning liquid pump 643. In other words, even when the bypass valve 682 is opened and closed repeatedly in a short period of time, it is possible to prevent the cleaning liquid pump 643 from being repeatedly activated in a short period of time. As a result, the life of the cleaning liquid pump 643 (that is, the driving unit of the cleaning liquid supply unit 64) can be extended. In addition, the time difference between the detection of the valve closing process and the stop of the supply of the cleaning liquid is realized by a delay timer, for example.

As described above, when the supply control unit 72 detects the valve closing process of the bypass valve 682 while the bypass valve 682 is open, it starts supplying the reducing agent from the reducing agent supply unit 63 to the nozzle 61 after the predetermined time has elapsed. . Therefore, when the valve opening process of the temporarily closed bypass valve 682 is restarted before the predetermined time (for example, about 10 seconds) elapses, the supply of the reducing agent from the reducing agent supply unit 63 to the nozzle 61 is still stopped. Accordingly, even if the opening and closing of the bypass valve 682 is repeated in a short period of time, it is possible to suppress the supply of the reducing agent to the exhaust gas collector 422 with the bypass valve 682 open, thereby suppressing the exhaust gas including the reducing agent and the like. The gas flows into the turbine 51 and the flue 81 through the bypass flow path 681 .

In the internal combustion engine 1 , when some abnormality occurs, the denitration system 6 performs a process of opening the bypass valve 682 and stopping the reducing agent pump 633 (so-called SCR OFF or SCR stop). In this case, the valve opening process of the bypass valve 682 is started (step S11 ) and the operation of the reducing agent pump 633 is stopped, thereby stopping the supply of the reducing agent to the nozzle 61 (step S12 ). That is, when SCR closing or SCR stop is performed, when the supply control unit 72 detects the valve opening process of the bypass valve 682 and/or the stopping process of the reducing agent pump 633 , the supply of the reducing agent to the nozzle 61 is stopped. This can suppress the reducing agent from flowing into the downstream side of the reactor 66 . Thereafter, the nozzle 61 and the common pipe 62 are cleaned.

In the internal combustion engine 1 , when the supply control unit 72 detects the stop process of the reducing agent pump 633 , it is preferable to control the switching unit 634 to switch the delivery location of the reducing agent from the nozzle 61 to the other configuration (for example, reducing agent supply source 631 or reducing agent pipe 632). This can prevent or suppress the reducing agent remaining in the reducing agent pipe 632 between the reducing agent pump 633 and the switching unit 634 when the SCR is turned off, etc., from moving to the nozzle 61 side and leaking from the nozzle 61 (that is, from the nozzle 61 droplets of reducing agent).

Next, the internal combustion engine 1a according to the second embodiment of the present invention will be described. FIG. 9 is a diagram showing a part of the structure of the denitration system 6a of the internal combustion engine 1a. The internal combustion engine 1a has the same structure as the internal combustion engine 1 shown in FIG. 1 except that the switching part 634 is omitted from the reducing agent supply part 63. In the following description, each component of the internal combustion engine 1 a is denoted by the same reference numeral as the corresponding component of the internal combustion engine 1 .

In the internal combustion engine 1a, the reducing agent supply part 63 includes a reducing agent supply source 631, a reducing agent pipe 632, and a reducing agent pump 633. Similar to the internal combustion engine 1 described above, the reducing agent supply source 631 stores the reducing agent. The reducing agent pipe 632 is a pipe that connects the reducing agent supply source 631 and the nozzle 61 . The reducing agent pump 633 delivers the reducing agent from the reducing agent supply source 631 to the nozzle 61 via the reducing agent pipe 632 .

In the internal combustion engine 1 a, the operation of the bypass valve 682 (see FIG. 1 ) during the valve opening process and the valve closing process is substantially the same as steps S11 to S20 shown in FIG. 7 . In the internal combustion engine 1 a , the supply of the reducing agent in step S12 is stopped by not switching the supply of the reducing agent by the switching unit 634 , but by stopping the reducing agent pump 633 .

Specifically, when detecting the valve opening process of the bypass valve 682 , the supply control unit 72 stops the operation of the reducing agent pump 633 , thereby stopping the supply of the reducing agent from the nozzle 61 to the exhaust flow path 42 . This makes it possible to stop the supply of the reducing agent to the exhaust flow path 42 with a simple structure. In addition, the structure of the internal combustion engine 1 a is the same as that of the internal combustion engine 1 , and is particularly suitable for an internal combustion engine in which the turbine 51 is provided downstream of the reactor 66 .

Various modifications can be made to the internal combustion engine 1 and the internal combustion engine 1a.

For example, in the reducing agent supply part 63 of the denitration system 6, the check valve 635 may be omitted. Similarly, in the cleaning liquid supply part 64 and the gas supply part 65, the check valve 645 and the check valve 655 may be omitted. The same applies to the denitration system 6a.

In the reducing agent supply part 63 of the denitration system 6, the circulation flow path 636 may be omitted. In this case, the delivery location of the reducing agent from the reducing agent pump 633 can be switched, for example, between the nozzle 61 and the drain pipe by the switching unit 634 so that the reducing agent not supplied to the nozzle 61 is discarded. Furthermore, the switching part 634 does not necessarily need to be a solenoid valve, and may also be a component with other structures (for example, an electric valve driven by a motor or a pilot valve driven by air).

In the control by the supply control unit 72 , when the valve closing process of the bypass valve 682 is detected during the supply of the cleaning liquid from the cleaning liquid supply unit 64 , the supply of the cleaning liquid does not necessarily need to be stopped after the detection of the valve closing process. It can be performed after a specified time has elapsed. For example, it can also be performed immediately after the valve closing process is detected.

In addition, when cleaning the nozzle 61 after stopping the supply of the reducing agent to the nozzle 61 , the supply of gas from the gas supply unit 65 does not necessarily need to be performed after a predetermined time has elapsed since the supply of the cleaning liquid from the cleaning liquid supply unit 64 , for example, it may be performed substantially simultaneously with the supply of the cleaning liquid. In cleaning the nozzle 61 , it is not necessarily necessary to supply the cleaning liquid, and the nozzle 61 may be cleaned using only the supply of gas from the gas supply unit 65 . In this case, the cleaning liquid supply part 64 may be omitted. In addition, it is not necessarily necessary to clean the nozzle 61 after the supply of the reducing agent is stopped. In this case, the cleaning liquid supply part 64 and the gas supply part 65 can be omitted.

In the denitration system 6 , it is not necessarily necessary to use the switching unit 634 to switch the reducing agent transportation location from the nozzle 61 to another structure when the SCR is turned off, so the switching unit 634 does not need to be driven.

In the denitration system 6, a multi-port valve spanning the reducing agent pipe 632 and the cleaning liquid pipe 642 is provided as the switching unit 634 shown in FIG. 3, and when the bypass valve 682 is opened, the multi-port valve is switched , the delivery location of the reducing agent from the reducing agent pump 633 is switched from the nozzle 61 to the reducing agent supply source 631, and at the same time, the cleaning liquid from the cleaning liquid pump 643 can be delivered to the nozzle 61 through the multi-port valve.

The nozzle 61 does not necessarily need to supply the reducing agent to the exhaust gas collector 422 , but may supply the reducing agent to any part of the exhaust gas flow path 42 . For example, the nozzle 61 can be attached to the exhaust pipe 421 or the combustion chamber 20 to supply the reducing agent to the exhaust pipe 421 or the combustion chamber 20 .

The internal combustion engine 1 and the internal combustion engine 1 a do not necessarily need to include a plurality of combustion chambers 20 , nor do they need to provide an exhaust gas collector 422 in the exhaust gas flow path 42 .

The supercharger 5 can be omitted from the internal combustion engine 1 and the internal combustion engine 1a. In this case, the reactor 66 and the bypass flow path 681 can be directly connected to the flue 81 .

The internal combustion engine 1 and the internal combustion engine 1a do not necessarily need to be the main engine of the ship, nor do they need to be a two-stroke diesel engine. The internal combustion engine 1 and the internal combustion engine 1 a may be, for example, a four-stroke diesel engine, or may be an engine other than a diesel engine. The internal combustion engine 1 and the internal combustion engine 1a can be used for purposes other than main engines of ships (for example, engines of automobiles, etc.). In addition, the internal combustion engine 1 and the internal combustion engine 1a can be used as a generator installed in a body of a garbage incineration facility or the like.

The configurations of the above-described embodiments and modifications may be appropriately combined as long as they do not conflict with each other.

The invention has been described and explained in detail, but the description is illustrative and not restrictive. Therefore, various modifications and modes can be made without departing from the scope of the present invention.

1. 1a: Internal combustion engine 2: Cylinder 3:piston 5:Supercharger 6. 6a: Denitrification system 20: Combustion chamber 21: Cylinder liner 22:Cylinder head 23:Scavenging port 24:Exhaust port 25:Exhaust valve 31:Piston head 32:piston rod 41:Scavenging air flow path 42:Exhaust flow path 43:Air cooler 51:Turbine 52:Compressor 61:Nozzle 62:Shared piping 63:Reducing agent supply department 64: Cleaning fluid supply department 65:Gas supply department 66:Reactor 67:SCR flow path 70:Control system 71:Testing Department 72: Supply Control Department 81: Flue 82: Inspiratory path 411:Scavenging chamber 412:Scavenging collector 421:Exhaust piping 422:Exhaust collector 631:Reducing agent supply source 632:Reducing agent piping 633:Reducing agent pump 634:Switching department 635, 645, 655: Check valve 636: Circulation flow path 641: Cleaning fluid supply source 642:Cleaning fluid piping 643:Cleaning fluid pump 651:Gas supply source 652:Gas piping 653:Gas supply valve 681:Bypass flow path 682:Bypass valve S11～S20: steps

FIG. 1 is a diagram showing the structure of an internal combustion engine according to the first embodiment. FIG. 2 is a diagram showing a part of the structure of the internal combustion engine. FIG. 3 is a diagram showing a part of the structure of the denitration system. FIG. 4 is a diagram showing the structure of an internal combustion engine. FIG. 5 is a diagram showing a part of the structure of the internal combustion engine. FIG. 6 is a diagram showing a part of the structure of the internal combustion engine. FIG. 7 is a diagram showing a flow of stopping the supply of the reducing agent. Fig. 8 is a diagram showing the structure of an internal combustion engine. FIG. 9 is a diagram showing a part of the structure of the denitration system of the internal combustion engine according to the second embodiment.

1: Internal combustion engine

2: Cylinder

3:piston

5:Supercharger

6:Denitrification system

20: Combustion chamber

21: Cylinder liner

22:Cylinder head

23:Scavenging port

24:Exhaust port

25:Exhaust valve

31:Piston head

32:piston rod

41:Scavenging air flow path

42:Exhaust flow path

43:Air cooler

51:Turbine

52:Compressor

61:Nozzle

66:Reactor

67:SCR flow path

81: Flue

82: Inspiratory path

411:Scavenging chamber

412:Scavenging collector

421:Exhaust piping

422:Exhaust collector

681:Bypass flow path

682:Bypass valve

Claims (16)

An internal combustion engine, including: an exhaust flow path through which exhaust gas flows; a reducing agent supply unit that supplies a reducing agent to the exhaust flow path through a nozzle installed in the exhaust flow path and mixes it with the exhaust gas; and a reactor. The exhaust gas flowing in from the exhaust flow path is brought into contact with the catalyst to perform denitration treatment; the flue guides the exhaust gas passing through the reactor; the bypass flow path bypasses the reactor and passes the exhaust gas The air flow path is connected to the flue; a bypass valve opens and closes the bypass flow path; a turbine is configured between the reactor, the bypass flow path, and the flue, and passes through the exhaust The compressor rotates with the air; the compressor uses the rotation of the turbine as power to pressurize the suction air; and the supply control part controls the reducing agent supply part, and the reducing agent supply part includes: a reducing agent supply source, a storage the reducing agent; a pipe connecting the reducing agent supply source and the nozzle; and a pump transporting the reducing agent from the reducing agent supply source to the nozzle through the pipe, the supply control unit When the valve opening process of the bypass valve is detected, the reducing agent supply unit is controlled to stop supplying the reducing agent to the exhaust flow path. When the bypass valve is closed, the exhaust gas passing through the reactor flows into the turbine, and when the bypass valve is open, the exhaust gas passes through the reactor and the bypass The exhaust gas from the flow path flows into the turbine. The internal combustion engine according to claim 1, wherein the reducing agent supply part further includes a switching part provided on the pipe, and switches between the nozzle and other components other than the nozzle. The delivery place of the reducing agent delivered by the pump, when the supply control unit detects the valve opening process of the bypass valve, controls the switching unit so that the delivery place of the reducing agent is changed from the delivery place of the reducing agent. The nozzle is switched to the other configuration, thereby stopping the supply of the reducing agent from the nozzle to the exhaust gas flow path. The internal combustion engine according to claim 2, wherein the other component is the reducing agent supply source or the piping upstream of the switching unit. As in the internal combustion engine described in claim 3 of the patent application, the reducing agent supply part further includes a check valve, and the check valve is between the switching part and the nozzle and is provided near the nozzle. on the above mentioned piping. As in the internal combustion engine of claim 2, the reducing agent supply part further includes a check valve, the check valve is between the switching part and the nozzle, and is provided near the nozzle. on the above mentioned piping. The internal combustion engine according to claim 1, wherein when the supply control unit detects the valve opening process of the bypass valve, it stops the operation of the pump, thereby stopping the flow of water from the nozzle to the exhaust gas. The reducing agent is supplied from the gas flow path. The internal combustion engine according to any one of claims 1 to 6, further comprising: a gas supply unit that supplies gas to the nozzle, and stops supplying gas from the nozzle to the exhaust gas flow path. After the reducing agent is supplied, the supply control unit controls the gas supply unit to supply the gas to the nozzle. An internal combustion engine, including: an exhaust flow path through which exhaust gas flows; a reducing agent supply unit that supplies a reducing agent to the exhaust flow path through a nozzle installed in the exhaust flow path and mixes it with the exhaust gas; and a reactor. The exhaust gas flowing in from the exhaust flow path is brought into contact with the catalyst to perform denitration treatment; the flue guides the exhaust gas passing through the reactor; the bypass flow path bypasses the reactor and passes the exhaust gas The air flow path is connected to the flue; a bypass valve opens and closes the bypass flow path; a turbine is configured between the reactor, the bypass flow path, and the flue, and passes through the exhaust The gas rotates; a compressor uses the rotation of the turbine as power to pressurize the suction gas; and A supply control unit controls the reducing agent supply unit, and the reducing agent supply unit includes: a reducing agent supply source that stores the reducing agent; a pipe that connects the reducing agent supply source and the nozzle; and a pump that connects the reducing agent supply source to the nozzle. The reducing agent supply source delivers the reducing agent to the nozzle via the pipe, and the supply control unit detects an opening process of the bypass valve or a stop process of the pump. The reducing agent supply unit controls the supply of the reducing agent to the exhaust gas flow path, and in a state where the bypass valve is closed, the exhaust gas passing through the reactor flows into the turbine. When the bypass valve is open, the exhaust gas passing through the reactor and the bypass flow path flows into the turbine, and the reducing agent supply part further includes: a switching part provided on the pipe, The supply control unit switches the delivery location of the reducing agent delivered by the pump between the nozzle and a structure other than the nozzle, and the supply control unit detects the valve opening process of the bypass valve or the During the stop process of the pump, the switching unit is controlled to switch the delivery location of the reducing agent from the nozzle to the other configuration, thereby stopping supply from the nozzle to the exhaust gas flow path. The reducing agent, the reducing agent supply part further includes a check valve, and the check valve is provided on the pipe near the nozzle between the switching part and the nozzle. The internal combustion engine according to claim 8, wherein the other component is the reducing agent supply source or the piping upstream of the switching unit. The internal combustion engine according to claim 8 or 9, further comprising: a gas supply unit that supplies gas to the nozzle, and stops supplying the reducing agent from the nozzle to the exhaust flow path. , the supply control unit controls the gas supply unit to supply the gas to the nozzle. The internal combustion engine according to claim 10, further comprising: a cleaning fluid supply unit that supplies cleaning fluid to the nozzle, and after stopping the supply of the reducing agent from the nozzle to the exhaust flow path, the The supply control section controls the cleaning liquid supply section to supply the cleaning liquid to the nozzle, and the supply of the gas from the gas supply section to the nozzle is started from the cleaning liquid supply section to the nozzle. The nozzle supplies the cleaning liquid and starts after a predetermined time has elapsed. The internal combustion engine according to claim 11, wherein when the supply control unit detects the valve closing process of the bypass valve while the bypass valve is open, the supply control unit stops the valve from the bypass valve after a predetermined time has elapsed. The cleaning liquid supply part supplies the cleaning liquid to the nozzle. An internal combustion engine includes: an exhaust flow path for exhaust gas to flow; a reducing agent supply unit that supplies the reducing agent to the exhaust gas flow channel through a nozzle installed in the exhaust gas flow channel and mixes it with the exhaust gas; and a reactor that brings the exhaust gas flowing in from the exhaust gas flow channel into contact with the catalyst to carry out denitration treatment; a flue to guide the exhaust gas through the reactor; a bypass flow path to bypass the reactor and connect the exhaust flow path to the flue; a bypass valve to open and closing the bypass flow path; a turbine arranged between the reactor, the bypass flow path, and the flue, and rotated by the exhaust gas; and a compressor using the rotation of the turbine as power and pressurizing the suction air; and a supply control part to control the reducing agent supply part, and the reducing agent supply part includes: a reducing agent supply source to store the reducing agent; and a pipe to connect the reducing agent supply source to The nozzle is connected; and a pump transports the reducing agent from the reducing agent supply source to the nozzle through the pipe, and the supply control unit detects the valve opening process of the bypass valve or the During the pump stop process, the reducing agent supply unit is controlled to stop supplying the reducing agent to the exhaust flow path, and the exhaust gas passing through the reactor is closed in a state where the bypass valve is closed. The air flows into the turbine, When the bypass valve is open, the exhaust gas passing through the reactor and the bypass flow path flows into the turbine. The internal combustion engine further includes a gas supply part that supplies gas to the nozzle. After stopping the supply of the reducing agent from the nozzle to the exhaust flow path, the supply control unit controls the gas supply unit to supply the gas to the nozzle, and the internal combustion engine further includes a cleaning fluid supply unit , supply cleaning liquid to the nozzle, and after stopping supply of the reducing agent from the nozzle to the exhaust flow path, the supply control unit controls the cleaning liquid supply unit to supply the cleaning liquid to the nozzle. The supply of the cleaning liquid from the gas supply part to the nozzle is started after a predetermined time has elapsed since the supply of the cleaning liquid from the cleaning liquid supply part to the nozzle is started. The supply control When the unit detects the valve closing process of the bypass valve in the open state of the bypass valve, after a predetermined time has elapsed, the supply of the cleaning liquid from the cleaning liquid supply unit to the nozzle is stopped. The internal combustion engine according to claim 13, wherein the reducing agent supply part further includes a switching part provided on the pipe, and switches between the nozzle and other components other than the nozzle. The reducing agent transported by the pump is transported, and when the supply control unit detects the valve opening process of the bypass valve or the stopping process of the pump, the switching unit controls the switching unit so that the reducing agent is transported by the pump. The delivery method of the reducing agent is switched from the nozzle to the other configuration, thereby stopping the delivery of the reducing agent from the nozzle to the other structure. The exhaust flow path supplies the reducing agent. The internal combustion engine according to claim 14, wherein the other component is the reducing agent supply source or the piping upstream of the switching unit. A control system for controlling the reducing agent supply part in an internal combustion engine including an exhaust gas flow path, a reducing agent supply part, a reactor, a flue bypass flow path, a bypass valve, a turbine, and a compressor, wherein the exhaust gas The flow path allows the exhaust gas to flow; the reducing agent supply unit supplies the reducing agent to the exhaust gas flow path through a nozzle installed in the exhaust gas flow path and mixes it with the exhaust gas; and the reactor makes the exhaust gas flow from the exhaust gas. The exhaust gas flowing into the flow path contacts the catalyst to perform denitration treatment; the flue guides the exhaust gas passing through the reactor; the bypass flow path bypasses the reactor and connects the exhaust gas flow path with The flue is connected; the bypass valve opens and closes the bypass flow path; the turbine is disposed between the reactor, the bypass flow path, and the flue, and is emitted by exhaust gas. Rotate; the compressor uses the rotation of the turbine as power to pressurize the suction air, and with the bypass valve closed, the exhaust gas passing through the reactor flows into the turbine, When the bypass valve is open, the exhaust gas passing through the reactor and the bypass flow path flows into the turbine, wherein the reducing agent supply part includes: a reducing agent supply source that stores the reducing agent. agent; piping to connect the reducing agent supply source and the nozzle; and a pump to transport the reducing agent from the reducing agent supply source to the nozzle through the piping, The control system includes: a detection unit that detects the valve opening process of the bypass valve; and a supply control unit that supplies the reducing agent when the detection unit detects the valve opening process of the bypass valve. The control unit performs control to stop the supply of the reducing agent to the exhaust gas flow path.