JP2024046331A - engine intake and exhaust system - Google Patents

Abstract

[Problem] To suppress greenhouse gas emissions. [Solution] An intake and exhaust system 1 for an engine 100 includes the engine 100, an intake passage 200 that communicates with a combustion chamber 108 of the engine 100, an ammonia injector provided in the intake passage 200 or the combustion chamber 108, a throttle valve V1 provided in the intake passage 200, and a control device 600 that controls the opening degree of the throttle valve V1 based on the output of the engine 100. [Selected Figure]

Description

The present disclosure relates to an engine intake and exhaust system.

Various engine-related proposals have been made in the past. For example, as disclosed in Patent Document 1, a technology has been proposed that uses ammonia as engine fuel. By using ammonia as engine fuel, carbon dioxide emissions are suppressed.

JP 2020-148198 A

By the way, when ammonia is used as engine fuel, if the ammonia concentration, which is the ratio of the amount of ammonia supplied to the amount of air supplied to the combustion chamber of the engine, is low, nitrous oxide (N ₂ O), which is a greenhouse gas, will be A lot of it is discharged. Therefore, it is desirable to optimize the ammonia concentration and suppress greenhouse gas emissions.

The objective of this disclosure is to provide an engine intake and exhaust system that can reduce greenhouse gas emissions.

In order to solve the above problems, an engine intake and exhaust system of the present disclosure includes an engine, an intake flow path communicating with a combustion chamber of the engine, an ammonia injection valve provided in the intake flow path or the combustion chamber, and an intake flow path. and a control device that controls the opening degree of the throttle valve based on the output of the engine.

The control device may fully open the throttle valve when the output is higher than the reference output, and may open the throttle valve less than fully open when the output is lower than the reference output.

When the output is lower than the reference output, the control device may reduce the opening degree of the throttle valve as the output decreases.

The turbocharger has an exhaust passage communicating with the combustion chamber, a compressor provided in the intake passage, and a turbine provided in the exhaust passage; a bypass passage connecting the intake passage upstream and downstream of the compressor; and a bypass valve provided in the bypass passage. The control device may fully open the bypass valve when the output is lower than the reference output, and may open the bypass valve less than when fully open when the output is higher than the reference output.

The control device may reduce the opening of the bypass valve as the output increases when the output is higher than the reference output.

According to the present disclosure, greenhouse gas emissions can be suppressed.

FIG. 1 is a schematic diagram showing the configuration of an intake and exhaust system according to an embodiment of the present disclosure. FIG. 2 is a schematic diagram showing the configuration of each cylinder of the engine according to the embodiment of the present disclosure. FIG. 3 is a flowchart showing an example of a process flow related to the control of the throttle valve performed by the control device according to the embodiment of the present disclosure. FIG. 4 is a diagram illustrating an example of the relationship between the engine output, the bypass valve opening degree, and the throttle valve opening degree according to the embodiment of the present disclosure. FIG. 5 is a schematic diagram showing the configuration of an intake and exhaust system according to a first modification. FIG. 6 is a schematic diagram showing the configuration of an intake and exhaust system according to a second modification.

Embodiments of the present disclosure will be described below with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiments are merely examples for easy understanding, and do not limit the present disclosure unless otherwise specified. In this specification and drawings, elements having substantially the same functions and configurations are designated by the same reference numerals to omit redundant explanation, and elements not directly related to the present disclosure are omitted from illustration. do.

FIG. 1 is a schematic diagram showing the configuration of an intake/exhaust system 1 according to the present embodiment. The intake and exhaust system 1 is a system related to intake and exhaust of the engine 100. As shown in FIG. 1, the intake and exhaust system 1 includes an engine 100, an intake flow path 200, an exhaust flow path 300, a supercharger 400, a bypass flow path 500, and a control device 600.

Engine 100 is a gas engine. Engine 100 has multiple cylinders. In the example of FIG. 1, engine 100 has a first cylinder #1, a second cylinder #2, a third cylinder #3, a fourth cylinder #4, a fifth cylinder #5, and a sixth cylinder #6. However, the number of cylinders of engine 100 may be other than six.

Figure 2 is a schematic diagram showing the configuration of each cylinder of the engine 100 according to this embodiment. In Figure 2, the intake port 104a, the exhaust port 104b, the ammonia injector 112, and the non-ammonia fuel injector 114 are illustrated on the same cross section. However, the intake port 104a, the exhaust port 104b, the ammonia injector 112, and the non-ammonia fuel injector 114 do not have to be located on the same cross section.

As shown in FIG. 2, the engine 100 includes a cylinder liner 102, a cylinder head 104, and a piston 106. The piston 106 is housed within the cylinder liner 102. The cylinder liner 102, the cylinder head 104, and the piston 106 form a combustion chamber 108.

The cylinder head 104 is formed with an intake port 104a and an exhaust port 104b. Intake port 104a and exhaust port 104b open into combustion chamber 108. The intake valve 110a opens and closes the opening on the combustion chamber 108 side of the intake port 104a. The exhaust valve 110b opens and closes the opening on the combustion chamber 108 side of the exhaust port 104b. The opening and closing operations of the intake valve 110a and the exhaust valve 110b are performed in accordance with the rotation of a camshaft (not shown).

A pipe forming a branch passage 202 of an intake passage 200, which will be described later, is connected to the intake port 104a. Intake air flows into the combustion chamber 108 via the intake port 104a. A pipe forming a branch flow path 302 of an exhaust flow path 300, which will be described later, is connected to the exhaust port 104b. Exhaust gas is exhausted from the combustion chamber 108 through the exhaust port 104b.

Ammonia injection valve 112 is connected to a source of ammonia used as fuel. The ammonia supply source is, for example, an ammonia tank (not shown). In the example of FIG. 2, the ammonia injection valve 112 is provided in a branch flow path 202 of the intake flow path 200. The tip of the ammonia injection valve 112 faces the intake port 104a. The ammonia injection valve 112 injects ammonia as fuel gas into the intake port 104a. Gaseous ammonia is injected from the ammonia injection valve 112. Thus, engine 100 is an engine that uses ammonia as fuel.

However, the ammonia injector 112 may be provided in the combustion chamber 108. In this case, the ammonia injector 112 is provided, for example, in the cylinder head 104 so as to face the inside of the combustion chamber 108, and injects ammonia directly into the combustion chamber 108. In this case, gaseous or liquid ammonia is injected from the ammonia injector 112.

The non-ammonia fuel injection valve 114 is connected to a source of non-ammonia fuel, which is a fuel other than ammonia. For example, light oil is used as the non-ammonia fuel. In this case, the non-ammonia fuel supply source is, for example, a light oil tank (not shown). However, fuel other than light oil such as heavy oil may be used as the non-ammonia fuel. A non-ammonia fuel injector 114 is provided in the combustion chamber 108. In the example of FIG. 2, the non-ammonia fuel injection valve 114 is provided in the cylinder head 104 so as to face into the combustion chamber 108, and injects non-ammonia fuel directly into the combustion chamber 108. For example, liquid non-ammonia fuel is injected from the non-ammonia fuel injection valve 114.

Ammonia is less combustible than other fuels. Therefore, in the engine 100, in order to prevent a decrease in combustibility in the combustion chamber 108 and ensure combustibility, a non-ammonia fuel is used in addition to ammonia.

Engine 100 is a four-stroke engine. In the intake stroke, ammonia is injected from the ammonia injection valve 112, the intake valve 110a is opened, and the exhaust valve 110b is closed. The piston 106 moves toward the bottom dead center, and intake air and ammonia are sucked into the combustion chamber 108 from the intake port 104a. In the compression stroke, the intake valve 110a and the exhaust valve 110b are in a closed state. The piston 106 moves toward top dead center, and the air-fuel mixture in the combustion chamber 108 is compressed. At the timing when the piston 106 reaches near the top dead center, non-ammonia fuel is injected from the non-ammonia fuel injection valve 114, and the combustibility in the combustion chamber 108 is enhanced. As a result, the air-fuel mixture within the combustion chamber 108 is ignited and combusted. During the expansion stroke, the piston 106 is pushed toward the bottom dead center. In the exhaust stroke, the intake valve 110a is closed and the exhaust valve 110b is opened. The piston 106 moves toward the top dead center, and the exhaust gas after combustion is discharged from the combustion chamber 108 through the exhaust port 104b. Hereinafter, referring back to FIG. 1, the explanation will be continued.

Intake flow path 200 communicates with combustion chamber 108 of engine 100. Intake air, which is air supplied to the combustion chamber 108, flows through the intake flow path 200. An intake port (not shown) through which air is taken in from the outside is provided at the upstream end of the intake flow path 200. The intake flow path 200 has a plurality of branch flow paths 202 each communicating with a plurality of combustion chambers 108 . The plurality of branch channels 202 are provided on the downstream side of the intake channel 200. Each of the plurality of combustion chambers 108 and the intake flow path 200 are connected by a plurality of branch flow paths 202. As described above, the pipe forming the branch flow path 202 is connected to the intake port 104a of the engine 100. The intake port 104a corresponds to the downstream end of the branch flow path 202. Intake port 104a is included in intake flow path 200.

Each branch flow path 202 is provided with a throttle valve V1. However, the slot valve V1 may be provided upstream of the branch flow path 202 in the intake flow path 200. The throttle valve V1 adjusts the amount of air supplied to each combustion chamber 108 through each branch flow path 202. By changing the opening degree of the throttle valve V1, the amount of air supplied to the combustion chamber 108 changes. Specifically, the larger the opening degree of the throttle valve V1, the larger the amount of air supplied to the combustion chamber 108. In the intake/exhaust system 1, greenhouse gas emissions are suppressed by appropriately controlling the opening degree of the throttle valve V1. Details of the control of the throttle valve V1 will be described later.

Exhaust flow path 300 communicates with combustion chamber 108 of engine 100. Exhaust gas discharged from the combustion chamber 108 flows through the exhaust flow path 300 . An exhaust port (not shown) through which exhaust gas is discharged to the outside is provided at the downstream end of the exhaust flow path 300. The exhaust flow path 300 has a plurality of branch flow paths 302 each communicating with a plurality of combustion chambers 108 . The plurality of branch channels 302 are provided on the upstream side of the exhaust channel 300. As described above, the pipe forming the branch flow path 302 is connected to the exhaust port 104b of the engine 100. The exhaust port 104b corresponds to the upstream end of the branch flow path 302. Exhaust port 104b is included in exhaust flow path 300.

Supercharger 400 includes a compressor 402 and a turbine 404. The impeller of compressor 402 and the impeller of turbine 404 rotate as a unit. The impeller of the compressor 402 and the impeller of the turbine 404 are connected by a shaft.

The compressor 402 is provided in the intake flow path 200 on the upstream side of the branch flow path 202 . Compressor 402 compresses intake air taken in from the intake port and sends it downstream. An intercooler 204 is provided in the intake flow path 200 upstream of the branch flow path 202 and downstream of the compressor 402 . The intake air flowing inside the intercooler 204 is cooled by exchanging heat with air outside the intercooler 204 or cooling water supplied from the outside. The intake air that has passed through the intercooler 204 is sent to each combustion chamber 108 via each branch flow path 202.

The upstream and downstream sides of the intake flow path 200 relative to the compressor 402 are connected by a bypass flow path 500. In the example of FIG. 1, the upstream end of the bypass flow path 500 is connected to the upstream side of the intake flow path 200 relative to the compressor 402. The downstream end of the bypass flow path 500 is connected to the downstream side of the intake flow path 200 relative to the intercooler 204. A portion of the intake air flowing downstream of the compressor 402 in the intake flow path 200 passes through the bypass flow path 500, bypasses the compressor 402, and can be sent to the upstream side of the intake flow path 200 relative to the compressor 402.

The bypass flow passage 500 is provided with a bypass valve V2. The bypass valve V2 adjusts the flow rate of air flowing through the bypass flow passage 500. By changing the opening degree of the bypass valve V2, the flow rate of air sent to the bypass flow passage 500 from the intake air flowing downstream of the compressor 402 in the intake flow passage 200 changes. Specifically, the larger the opening degree of the bypass valve V2, the greater the flow rate of air sent from the intake air flow passage 200 downstream of the compressor 402 to the bypass flow passage 500, and the smaller the flow rate of air sent to the branch flow passage 202. Details of the control of the bypass valve V2 will be described later.

The turbine 404 is provided downstream of the branch passage 302 in the exhaust flow path 300. The exhaust gas discharged from the engine 100 is sent to the turbine 404 through each branch passage 302. The turbine 404 generates rotational power by rotating the impeller of the turbine 404 with the exhaust. The rotational power generated by the turbine 404 is transmitted to the compressor 402 via the shaft. The catalyst 304 is provided downstream of the turbine 404 in the exhaust flow path 300. The exhaust gas that passes through the turbine 404 is sent to the catalyst 304. The catalyst 304 removes harmful components in the exhaust gas. The exhaust gas that passes through the catalyst 304 is discharged from the exhaust port. The catalyst 304 is, for example, an ammonia decomposition catalyst that removes unburned ammonia, or a particulate filter that removes particulate matter.

The control device 600 includes a central processing unit (CPU), a ROM in which programs and the like are stored, and a RAM as a work area. The control device 600 controls the operation of each device in the intake and exhaust system 1. For example, the control device 600 controls the operation of the engine 100, the throttle valve V1, and the bypass valve V2.

Further, the control device 600 acquires information from each sensor in the intake and exhaust system 1. For example, in the intake/exhaust system 1, the intake pressure sensor 206 is provided in the intake flow path 200, and the N ₂ O sensor 306 is provided in the exhaust flow path 300. The intake pressure sensor 206 detects intake pressure, which is the pressure of intake air in the intake flow path 200. In the example of FIG. 1, the intake pressure sensor 206 is provided upstream of the branch channel 202 in the intake channel 200 and downstream of the downstream end of the bypass channel 500. N ₂ O sensor 306 detects the N ₂ O discharge concentration, which is the concentration of N ₂ O discharged from exhaust flow path 300 . In the example of FIG. 1, the N ₂ O sensor 306 is provided downstream of the catalyst 304 in the exhaust flow path 300.

Figure 3 is a flowchart showing an example of the process flow for controlling the throttle valve V1 performed by the control device 600 according to this embodiment. For example, the control flow shown in Figure 3 is repeatedly executed at preset time intervals.

When the control flow shown in FIG. 3 is started, in step S101, the control device 600 acquires the engine output, which is the output of the engine 100. Here, the control device 600 changes the amount of ammonia injected from the ammonia injector 112 according to the engine output. Specifically, the control device 600 reduces the amount of ammonia injected as the engine output becomes lower. Therefore, the lower the engine output, the less ammonia is supplied to the combustion chamber 108.

After step S101, in step S102, the control device 600 acquires the intake pressure. The intake pressure can be acquired, for example, from the intake pressure sensor 206.

After step S102, in step S103, the control device 600 determines a target opening degree, which is a target value for the opening degree of the throttle valve V1. Here, the control device 600 determines the target opening degree of the throttle valve V1 based on the engine output. For example, the lower the engine output, the smaller the value the control device 600 determines as the target opening degree of the throttle valve V1. This reduces the amount of ammonia injection and the amount of ammonia supplied to the combustion chamber 108, so that the amount of air supplied to the combustion chamber 108 can be reduced. Therefore, fluctuations in the ammonia concentration due to fluctuations in the engine output are suppressed.

Further, it is preferable that the control device 600 determines the target opening degree of the throttle valve V1 based on the intake pressure in addition to the engine output. For example, when the engine output is constant, the control device 600 determines a smaller value as the target opening degree of the throttle valve V1 as the intake pressure becomes higher. This suppresses fluctuations in the amount of air supplied to the combustion chamber 108 due to fluctuations in intake pressure.

After step S103, in step S104, the control device 600 controls the opening degree of the throttle valve V1 to the target opening degree.

After step S104, in step S105, the control device 600 determines whether the N ₂ O emission concentration is within the target range. Specifically, control device 600 determines that the N ₂ O emission concentration is within the target range when the N ₂ O emission concentration is below the reference value. N ₂ O emission concentration may be obtained from N ₂ O sensor 306, for example. If it is determined that the N ₂ O emission concentration is within the target range (step S105/YES), the control flow shown in FIG. 3 ends. On the other hand, if it is determined that the N ₂ O emission concentration is outside the target range (step S105/NO), the process advances to step S106.

If the determination in step S105 is NO, the control device 600 adjusts the opening degree of the throttle valve V1 in step S106, and the control flow shown in FIG. 3 ends. In step S106, the control device 600 reduces the opening degree of the throttle valve V1 by a predetermined opening degree, for example. Further, the control device 600 may, for example, reduce the opening degree of the throttle valve V1 by the opening degree according to the difference between the N ₂ O emission concentration and the reference value. By adjusting the opening degree of the throttle valve V1 in step S106 as described above, even if it is determined in step S105 that the N ₂ O emission concentration is outside the target range, the N ₂ O emission concentration will be reduced. is adjusted within the target range.

As described above, in the intake and exhaust system 1, the control device 600 controls the opening degree of the throttle valve V1 based on the engine output, which is the output of the engine 100. This suppresses fluctuations in ammonia concentration due to fluctuations in engine output. Therefore, the emission of N ₂ O, which is a greenhouse gas, is suppressed due to the lower ammonia concentration.

In the above, an example of the flow of the process related to the control of the throttle valve V1 performed by the control device 600 has been described with reference to FIG. 3. However, the process related to the control of the throttle valve V1 performed by the control device 600 is not limited to the above example. For example, steps S105 and S106 may be omitted from the control flow of FIG. 3 described above. Also, for example, in the above step S105, instead of determining whether the N ₂ O emission concentration is within the target range, the control device 600 may determine whether the ammonia concentration is within the target range. Even in this case, if the determination in step S105 is NO, the process proceeds to step S106, and the opening degree of the throttle valve V1 is adjusted. For example, in the case where a pressure sensor is provided downstream of the throttle valve V1 in each branch passage 202, the control device 600 can estimate the amount of air supplied to the combustion chamber 108 based on the detection result of the pressure sensor. Therefore, the control device 600 can calculate the ammonia concentration based on the estimation result of the amount of air supplied to the combustion chamber 108 and the ammonia injection amount.

The control of the throttle valve V1 and the bypass valve V2 will be described in more detail below with reference to FIG. 4. FIG. 4 is a diagram showing an example of the relationship between the engine output, the opening degree of the bypass valve V2, and the opening degree of the throttle valve V1 according to the present embodiment. In FIG. 4, the horizontal axis shows the engine output, and the vertical axis shows the opening degree of the bypass valve V2 and the opening degree of the throttle valve V1.

In the above, the point that the amount of air supplied to the combustion chamber 108 is adjusted by controlling the throttle valve V1 has been mainly explained. However, the control device 600 can also adjust the amount of air supplied to the combustion chamber 108 by controlling the bypass valve V2.

As shown in FIG. 4, the control device 600 fully opens the throttle valve V1 when the engine output is higher than the reference output. On the other hand, when the engine output is lower than the reference output, the control device 600 reduces the opening of the throttle valve V1 to less than when it is fully open. The reference output can be set appropriately according to the specifications of the engine 100, etc. In the example of FIG. 4, when the engine output is higher than the reference output, the opening of the throttle valve V1 is 100% regardless of the engine output. On the other hand, when the engine output is lower than the reference output, the lower the engine output, the smaller the opening of the throttle valve V1.

Here, when the engine output is lower than the reference output, the amount of ammonia supplied to the combustion chamber 108 is reduced, and N ₂ O emissions due to the reduced ammonia concentration are more likely to occur. Therefore, in such a case, by making the opening of the throttle valve V1 smaller than when fully open, the decrease in ammonia concentration is suppressed, and the emission of N ₂ O is appropriately suppressed. In particular, when the engine output is lower than the reference output, the control device 600 reduces the opening of the throttle valve V1 as the engine output decreases. This more appropriately suppresses the decrease in ammonia concentration, and more appropriately suppresses the emission of N ₂ O.

On the other hand, when the engine output is higher than the reference output, by fully opening the throttle valve V1, the ammonia concentration is prevented from becoming excessively high, and the generation of unburned ammonia is appropriately suppressed.

As shown in FIG. 4, the control device 600 fully opens the bypass valve V2 when the engine output is lower than the reference output. On the other hand, when the engine output is higher than the reference output, the control device 600 makes the opening degree of the bypass valve V2 smaller than when it is fully open. In the example of FIG. 4, when the engine output is lower than the reference output, the opening degree of the bypass valve V2 is 100% regardless of the engine output. On the other hand, when the engine output is higher than the reference output, the higher the engine output, the smaller the opening degree of the bypass valve V2.

As described above, when the engine output is lower than the reference output, the amount of ammonia supplied to the combustion chamber 108 is reduced, and N ₂ O emissions due to the reduced ammonia concentration are more likely to occur. Therefore, in such a case, by fully opening the bypass valve V2, it is possible to increase the flow rate of air sent to the bypass flow path 500 out of the intake air flowing downstream of the compressor 402 in the intake flow path 200. This makes it possible to reduce the flow rate of air sent to the branch flow path 202. Therefore, since the amount of air supplied to the combustion chamber 108 can be reduced, the reduction in the ammonia concentration is suppressed, and the emission of N ₂ O is appropriately suppressed.

On the other hand, when the engine output is higher than the standard output, by making the opening degree of the bypass valve V2 smaller than when it is fully opened, the ammonia concentration is suppressed from becoming excessively high, and the generation of unburned ammonia is appropriately prevented. suppressed. In particular, when the engine output is higher than the reference output, the control device 600 reduces the opening degree of the bypass valve V2 as the engine output increases. Thereby, as the amount of ammonia injection increases and the amount of ammonia supplied to the combustion chamber 108 increases, the amount of air supplied to the combustion chamber 108 can be increased. Therefore, excessively high ammonia concentration is more appropriately suppressed, and generation of unburned ammonia is more appropriately suppressed.

Hereinafter, intake and exhaust systems according to each modification will be described with reference to FIGS. 5 and 6.

Figure 5 is a schematic diagram showing the configuration of an intake and exhaust system 1A according to a first modified example. As shown in Figure 5, the intake and exhaust system 1A according to the first modified example differs from the intake and exhaust system 1 described above in that flow paths 702, 704, and 706 that connect the intake flow path 200 and the exhaust flow path 300 are added.

As shown in FIG. 5, the intake and exhaust system 1A is provided with flow paths 702, 704, and 706 that connect the intake flow path 200 and the exhaust flow path 300. A portion of the intake air flowing through the intake flow path 200 is sent to the flow paths 702, 704, and 706, and can be sent to the exhaust flow path 300 through the flow paths 702, 704, and 706. Therefore, in the flow paths 702, 704, and 706, the upstream side is the intake flow path 200 side, and the downstream side is the exhaust flow path 300 side.

The upstream end of the flow path 702 is connected to the intake flow path 200 downstream of the intercooler 204 and upstream of the branch flow path 202 . The upstream end of the flow path 704 and the upstream end of the flow path 706 are connected to the downstream end of the flow path 702 . The downstream end of the flow path 704 is connected to the exhaust flow path 300 upstream of the turbine 404 and downstream of the branch flow path 302 . The downstream end of the flow path 706 is connected to the exhaust flow path 300 downstream of the turbine 404 and upstream of the catalyst 304 .

The flow path 702 is provided with a first valve V3. The first valve V3 is a flow rate adjustment valve that adjusts the flow rate of intake air sent from the intake flow path 200 to the flow path 702. By changing the opening degree of the first valve V3, the flow rate of intake air sent from the intake flow path 200 to the flow path 702 changes. Specifically, the larger the opening degree of the first valve V3, the greater the flow rate of the intake air sent from the intake flow path 200 to the flow path 702. A second valve V4 is provided at the merging portion of the flow path 702, flow path 704, and flow path 706. The second valve V4 is a flow path switch that switches between a state where the flow path 702 communicates with the flow path 704 and does not communicate with the flow path 706, and a state where the flow path 702 communicates with the flow path 706 and does not communicate with the flow path 704. It's a valve. The second valve V4 switches the supply destination of the intake air sent to the flow path 702 between the flow path 704 and the flow path 706. The second valve V4 is, for example, a three-way valve.

The intake air that passes through flow paths 702 and 704 and is sent from the intake flow path 200 to the exhaust flow path 300 is sent to the turbine 404, cooling the turbine 404. In the intake and exhaust system 1A, the control device 600 controls the opening of the first valve V3 and the switching of the flow paths by the second valve V4. This controls the flow rate of the intake air that passes through flow paths 702 and 704 and is sent from the intake flow path 200 to the exhaust flow path 300. Therefore, the turbine 404 can be appropriately cooled by the intake air.

The intake air that passes through flow paths 702 and 706 and is sent from the intake flow path 200 to the exhaust flow path 300 is sent to the catalyst 304, cooling the catalyst 304. As described above, in the intake and exhaust system 1A, the control device 600 controls the opening degree of the first valve V3 and the switching of the flow paths by the second valve V4. This controls the flow rate of the intake air that passes through flow paths 702 and 706 and is sent from the intake flow path 200 to the exhaust flow path 300. Therefore, the catalyst 304 can be appropriately cooled by the intake air.

It should be noted that one of the flow paths 704 and 706 may be omitted from the intake and exhaust system 1A. In that case, the intake air can still be used to cool either the turbine 404 or the catalyst 304 as appropriate.

FIG. 6 is a schematic diagram showing the configuration of an intake/exhaust system 1B according to a second modification. As shown in FIG. 6, in the intake/exhaust system 1B according to the second modification, compared to the intake/exhaust system 1 described above, channels 802, 804 connecting the intake channel 200 and the exhaust channel 300, The difference is that 806 is added.

As shown in FIG. 6, in the intake/exhaust system 1B, channels 802, 804, and 806 are provided that connect the intake channel 200 and the exhaust channel 300. A portion of the intake air flowing through the intake flow path 200 may be sent to the flow paths 802 , 804 , 806 , through the flow paths 802 , 804 , 806 , and into the exhaust flow path 300 . Therefore, in the flow paths 802, 804, and 806, the upstream side is the intake flow path 200 side, and the downstream side is the exhaust flow path 300 side.

The upstream end of the flow path 802 is connected to the intake flow path 200 downstream of the compressor 402 and upstream of the intercooler 204 . The upstream end of the flow path 804 and the upstream end of the flow path 806 are connected to the downstream end of the flow path 802 . The downstream end of the flow path 804 is connected to the exhaust flow path 300 upstream of the turbine 404 and downstream of the branch flow path 302 . The downstream end of the flow path 806 is connected to the exhaust flow path 300 downstream of the turbine 404 and upstream of the catalyst 304 .

A third valve V5 is provided in the flow path 804. The third valve V5 is a flow rate adjustment valve that adjusts the flow rate of the intake air that passes through the flow paths 802 and 804 and is sent from the intake flow path 200 to the exhaust flow path 300. The flow rate of the intake air that passes through the flow paths 802 and 804 changes as the opening degree of the third valve V5 changes. Specifically, the larger the opening degree of the third valve V5, the greater the flow rate of the intake air that passes through the flow paths 802 and 804. The intake air that passes through the flow paths 802 and 804 and is sent from the intake flow path 200 to the exhaust flow path 300 is sent to the turbine 404 and cools the turbine 404. In the intake and exhaust system 1B, the control device 600 controls the opening degree of the third valve V5. Thereby, the flow rate of the intake air that passes through the flow paths 802 and 804 and is sent from the intake flow path 200 to the exhaust flow path 300 is controlled. Therefore, the turbine 404 can be appropriately cooled by the intake air. Furthermore, by supplying high-temperature (i.e., high-enthalpy) intake air upstream of the intercooler 204 to the turbine 404, it is possible to assist in the recovery of energy in the turbine 404, which in turn assists in driving the compressor 402.

A fourth valve V6 is provided in the flow path 806. The fourth valve V6 is a flow rate adjustment valve that adjusts the flow rate of the intake air that passes through the flow paths 802 and 806 and is sent from the intake flow path 200 to the exhaust flow path 300. The flow rate of the intake air that passes through the flow paths 802 and 806 changes as the opening degree of the fourth valve V6 changes. Specifically, the larger the opening degree of the fourth valve V6, the greater the flow rate of the intake air that passes through the flow paths 802 and 806. The intake air that passes through the flow paths 802 and 806 and is sent from the intake flow path 200 to the exhaust flow path 300 is sent to the catalyst 304 and cools the catalyst 304. In the intake and exhaust system 1B, the control device 600 controls the opening degree of the fourth valve V6. Thereby, the flow rate of the intake air that passes through the flow paths 802 and 806 and is sent from the intake flow path 200 to the exhaust flow path 300 is controlled. Therefore, the catalyst 304 can be appropriately cooled by the intake air. Furthermore, by supplying high-temperature (i.e., high-enthalpy) intake air upstream of the intercooler 204 to the catalyst 304, the temperature rise of the catalyst 304 can be assisted.

Note that one of the flow path 804 and the flow path 806 may be omitted from the intake/exhaust system 1B. In that case as well, one of the turbine 404 and the catalyst 304 can be appropriately cooled by the intake air.

In addition, in the intake/exhaust system 1B, instead of the third valve V5 and the fourth valve V6, a flow rate adjustment valve is provided in the flow path 802 as in the above-mentioned intake/exhaust system 1A, and the flow path 802 and the flow path 804 are A flow path switching valve may be provided at the confluence with the flow path 806. Furthermore, in the intake/exhaust system 1A described above, instead of the first valve V3 and the second valve V4, flow rate adjustment valves may be provided in the flow path 704 and the flow path 706, respectively, as in the intake/exhaust system 1B.

Although the embodiments of the present disclosure have been described above with reference to the attached drawings, it goes without saying that the present disclosure is not limited to such embodiments. It is clear that a person skilled in the art can come up with various modified or revised examples within the scope of the claims, and it is understood that these also naturally fall within the technical scope of the present disclosure.

This disclosure can contribute, for example, to Goal 7 of the United Nations-led Sustainable Development Goals (SDGs): "Ensure access to affordable, reliable, sustainable and modern energy."

1 Intake and exhaust system 1A Intake and exhaust system 1B Intake and exhaust system 100 Engine 108 Combustion chamber 112 Ammonia injection valve 200 Intake flow path 300 Exhaust flow path 400 Supercharger 402 Compressor 404 Turbine 500 Bypass flow path 600 Control device V1 Throttle valve V2 Bypass valve

Claims (5)

The engine,
an intake passage communicating with a combustion chamber of the engine;
an ammonia injector provided in the intake passage or the combustion chamber;
a throttle valve provided in the intake passage;
a control device that controls an opening degree of the throttle valve based on an output of the engine;
Equipped with
Engine intake and exhaust system. The control device includes:
fully opening the throttle valve when the output is higher than a reference output;
when the output is lower than the reference output, the opening degree of the throttle valve is made smaller than when it is fully open;
An intake and exhaust system for an engine according to claim 1. When the output is lower than the reference output, the control device reduces the opening degree of the throttle valve as the output becomes lower.
3. The engine intake and exhaust system according to claim 2. an exhaust passage communicating with the combustion chamber;
a turbocharger including a compressor provided in the intake passage and a turbine provided in the exhaust passage;
a bypass flow passage connecting an upstream side and a downstream side of the compressor in the intake air flow passage;
a bypass valve provided in the bypass flow path;
Equipped with
The control device includes:
When the output is lower than the reference output, the bypass valve is fully opened;
When the output is higher than the reference output, the opening degree of the bypass valve is made smaller than when the bypass valve is fully open.
4. The engine intake and exhaust system according to claim 2 or 3. When the output is higher than the reference output, the control device decreases the opening degree of the bypass valve as the output increases.
The engine intake and exhaust system according to claim 4.

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