Engine device

Abstract

To provide an engine device capable of suppressing leakage of blow-by gas containing a toxic substance and thus improving safety without depending on single means when treating the blow-by gas.SOLUTION: An engine device 1 is driven by using fuel containing a toxic substance. As a device for treating blow-by gas, the engine device 1 includes: a plurality of treatment devices having different functions; and a path changeover valve 12 for switching to a treatment device that treats the blow-by gas out of the plurality of treatment devices. The toxic substance included in the fuel is ammonia or methanol. The engine device 1 includes an external driving pump 8 for causing the blow-by gas to flow in a blow-by path 6, and also includes an exhaust emission control catalyst device 9, a detoxification device 10 and an intake air reduction device 11, as the plurality of treatment devices.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an engine system that runs on a fuel that contains toxic substances. [Background technology]

[0002] Conventionally, some engine systems are operated by fuels containing toxic substances such as ammonia and methanol, i.e., "harmful substances that should be labeled" under the Industrial Safety and Health Act. In addition, in engine systems, fuel gas supplied to the combustion chamber may leak into the crank chamber (crank case) as blow-by gas. Therefore, engine systems are required to treat such blow-by gas.

[0003] For example, Patent Document 1 discloses a blow-by gas recirculation device used in an internal combustion engine in which a turbocharger and an intercooler for cooling the intake gas pressurized by the turbocharger are provided on the intake passage, and the device includes an air introduction passage for introducing the intake gas in the intake passage into the crankcase of the internal combustion engine, and a gas recirculation passage for recirculating the blow-by gas in the crankcase of the internal combustion engine into the intake passage. The gas recirculation passage is connected to the intake passage on the intake upstream side of the turbocharger, thereby recirculating the blow-by gas in the crankcase to the intake passage and causing it to flow again into the combustion chamber. In addition, the air introduction passage is connected to the intake passage on the intake downstream of the turbocharger and on the intake upstream of the intercooler, thereby supplying a part of the air compressed by the turbocharger into the crankcase and ventilating the crankcase. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 4383983 Summary of the Invention [Problem to be solved by the invention]

[0005] In an engine system, if fuel containing toxic and harmful substances such as ammonia and methanol, i.e., "harmful substances that should be labeled" under the Industrial Safety and Health Act, leaks from a location other than where it is likely to be present, such as the intake and exhaust pipes or fuel pipes, for example, if it leaks from the crankcase as blow-by gas, there is a possibility of human injury. In conventional technology such as Patent Document 1, the blow-by gas is treated by a single means of refluxing from the gas reflux passage to the intake passage, but if an abnormality occurs in this single means, the blow-by gas treatment function is impaired, and toxic and harmful substances may leak to the outside, reducing safety.

[0006] In addition, when blow-by gas in the crankcase is ventilated with air from a turbocharger that operates while the engine (internal combustion engine) is running, the turbocharger cannot be stopped to ventilate the blow-by gas trapped in the crankcase when the engine is stopped, which may result in toxic and harmful substances leaking to the outside.

[0007] Furthermore, if the only method used to treat blow-by gas is to recirculate (reduc) corrosive fuel such as ammonia back into the intake passage, there is a concern that the contamination of intake system parts will progress faster and the replacement intervals for intake system parts will become shorter. In contrast, if corrosion-resistant materials or corrosion-resistant coatings are used for the intake system parts, the cost will increase and there is a risk of the product being less attractive.

[0008] An object of the present invention is to provide an engine device that can improve safety by suppressing leakage of blow-by gas without relying on a single means for treating blow-by gas containing toxic substances. [Means for solving the problem]

[0009] In order to solve the above problems, the engine device of the present invention is an engine device that runs on fuel containing toxic substances, and is characterized in that it is equipped with a plurality of treatment devices with different functions as a device for treating blow-by gas, and a path switching valve that switches to the treatment device among the plurality of treatment devices that performs treatment of the blow-by gas. Effect of the Invention

[0010] According to the present invention, there is provided an engine device capable of suppressing leakage of blow-by gas and improving safety without relying on a single means for treating blow-by gas containing toxic substances. [Brief description of the drawings]

[0011] [Figure 1] 1 is a schematic diagram illustrating an example of an engine device according to an embodiment of the present invention. [Diagram 2] 4 is a graph showing the relationship between the concentration and mixture ratio of ammonia contained in blow-by gas input / output to / from an exhaust purification catalyst device in an engine device according to an embodiment of the present invention. [Diagram 3] 4 is a table showing an example of a processing device to be used depending on the state of the engine in the engine device according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] An engine device 1 according to an embodiment of the present invention will be described with reference to the drawings. As shown in Fig. 1, the engine device 1 includes an engine 2, an intake passage 3, an exhaust passage 4, and a turbocharger 5. Furthermore, the engine device 1 includes a blow-by path 6, a filter 7, an externally driven pump 8, an exhaust purification catalyst device 9, a detoxification device 10, an intake reduction device 11, a path switching valve 12, and a control unit 13.

[0013] Particularly in this embodiment, the engine device 1 is an engine that operates by feeding fuel containing toxic substances such as ammonia and methanol, i.e., “harmful substances that should be labeled” under the Industrial Safety and Health Act, into the combustion chamber 21a of the engine 2. The fuel is supplied to the combustion chamber 21a as a mixture with air.

[0014] The engine 2 is, for example, a four-stroke engine, and is configured with a cylinder block 20 including a plurality of cylinders 21 and a crankcase 22. Although six cylinders 21 are illustrated in Fig. 1, the number of cylinders 21 is not limited to six. As shown in Fig. 1, each cylinder 21 is configured with a cylinder 23, a piston 24, and a cylinder head 25.

[0015] The cylinder 23 is formed, for example, in a cylindrical shape within the cylinder block 20, and the piston 24 is slidably housed within the cylinder 23. The cylinder head 25 is attached to the upper side of the cylinder 23, and a combustion chamber 21a is formed inside the cylinder 23 and the cylinder head 25. The cylinder head 25 is provided with an ignition device (not shown) that ignites fuel in the combustion chamber 21a.

[0016] Each cylinder 23 of the multiple cylinders 21 is connected to a crankcase 22, and a crankshaft 26 is rotatably supported by the crankcase 22. A piston 24 of each cylinder 21 is connected to the crankshaft 26 via a connecting rod 27, and the reciprocating motion of the piston 24 is converted into the rotational motion of the crankshaft 26 via the connecting rod 27.

[0017] The cylinder head 25 is connected to the intake passage 3 via an intake port (not shown) and the like, and introduces the air-fuel mixture supplied from the intake passage 3 into the combustion chamber 21a. In addition, the cylinder head 25 is connected to the exhaust passage 4 via an exhaust port (not shown) and the like, and discharges exhaust gas generated in the combustion chamber 21a into the exhaust passage 4.

[0018] 1 illustrates an example in which the intake passage 3 and the multiple cylinders 21 are directly connected, but in order to connect the intake passage 3 and the multiple cylinders 21, an intake manifold having branch passages branching from the intake passage 3 to the multiple cylinders 21 may be provided between the intake passage 3 and the engine 2. Also, in FIG. 1 illustrates an example in which the exhaust passage 4 and the multiple cylinders 21 are directly connected, but in the case of connecting the exhaust passage 4 and the multiple cylinders 21, an exhaust manifold having branch passages branching from the exhaust passage 4 to the multiple cylinders 21 may be provided between the exhaust passage 4 and the engine 2.

[0019] The intake passage 3 is connected to a plurality of cylinders 21 of the engine 2 and supplies compressed and cooled air to each of the cylinders 21. A mixture of air supplied from the intake passage 3 and fuel supplied from a fuel tank (not shown) is supplied from the intake passage 3 to a combustion chamber 21a of each of the cylinders 21. A supercharger 5 is provided upstream in the intake direction of the intake passage 3 for compressing air or a mixture of fuel and air flowing through the intake passage 3 and sending it downstream in the intake direction.

[0020] The intake passage 3 is provided with a fuel supply device (not shown) that supplies fuel to the intake passage 3 on the upstream or downstream side of the turbocharger 5. The intake passage 3 may also be provided with an air filter (not shown) that purifies fresh air and introduces it into the intake passage 3, and an intercooler (not shown) that cools the air flowing through the intake passage 3. The fuel supply device is controlled by the control unit 13 in terms of the amount of fuel supplied (supply pressure) and supply timing. The fuel supply device may be formed of a venturi mixer that mixes fuel with the air flowing upstream or downstream of the turbocharger 5, or may be formed of an admission valve, an injector, or the like that injects fuel into the intake passage 3 for each of the cylinders 21.

[0021] The exhaust passage 4 is connected to a plurality of cylinders 21 of the engine 2, and discharges exhaust gas generated in each cylinder 21. An exhaust purification catalyst device 9 is provided downstream in the exhaust direction of the exhaust passage 4, which purifies the exhaust gas flowing through the exhaust passage 4 by catalytic reduction using a reducing agent such as urea water.

[0022] The turbocharger 5 compresses the air or air-fuel mixture flowing through the intake passage 3 and sends it downstream in the intake direction. The turbocharger 5 has a turbine 5a and a compressor 5b. The turbine 5a is disposed in the exhaust passage 4, and the compressor 5b is disposed in the intake passage 3. The turbine 5a is rotated by the exhaust gas flowing through the exhaust passage 4, and the compressor 5b is driven by the rotational force of the turbine 5a, thereby compressing the air or air-fuel mixture flowing through the intake passage 3.

[0023] The blow-by path 6 is connected to the crankcase 22. When fuel gas leaks from the combustion chamber 21a of each cylinder 21 into the crankcase 22, blow-by gas is generated in the crankcase 22, and the blow-by gas flows through the blow-by path 6. Furthermore, the blow-by path 6 is connected to a plurality of treatment devices having different functions for treating the blow-by gas of the crankcase 22.

[0024] In this embodiment, the exhaust gas purification catalyst device 9, the abatement device 10, and the intake air return device 11 are applied as the multiple treatment devices, but in the engine device 1 of the present invention, at least two of the exhaust gas purification catalyst device 9, the abatement device 10, and the intake air return device 11 may be applied. The blow-by path 6 has multiple branch paths 6a, 6b, and 6c that are branched on the way and lead to the exhaust gas purification catalyst device 9, the abatement device 10, and the intake air return device 11. A path switching valve 12 is provided at a branch point in the blow-by path 6 where the multiple branch paths 6a, 6b, and 6c are branched. The path switching valve 12 is controlled by a control unit 13 to switch the path so that the blow-by gas flowing through the blow-by path 6 is circulated to any one of the multiple branch paths 6a, 6b, and 6c.

[0025] The filter 7 is provided upstream in the flow direction of the blow-by gas in the blow-by path 6. The filter 7 separates oil mist contained in the blow-by gas flowing through the blow-by path 6 to produce an unburned air-fuel mixture, and is constituted by, for example, a mist separator.

[0026] The externally driven pump 8 is provided in the blow-by path 6 downstream of the filter 7 in the blow-by gas flow direction and upstream of the path switching valve 12 in the blow-by gas flow direction. The externally driven pump 8 is driven regardless of whether the engine 2 is running (operating) or not, and causes the blow-by gas to flow in the blow-by path 6 communicated with the crankcase 22, thereby ventilating the crankcase 22 and creating a negative pressure in the crankcase 22. This prevents the blow-by gas in the crankcase 22 from leaking from the crankcase 22 at a location other than the blow-by path 6, for example, preventing the blow-by gas from leaking from the crankcase 22 at a pivotal support location of the crankshaft 26. That is, the externally driven pump 8 functions as a treatment device that treats the blow-by gas in the crankcase 22.

[0027] The externally driven pump 8 may be driven at the same intensity regardless of whether the engine 2 is running (operating) or not, and may cause the blow-by gas to flow at the same intensity. Alternatively, the externally driven pump 8 may be driven at a relatively high intensity when the engine 2 is operating, and driven at a relatively low intensity when the engine 2 is stopped. Alternatively, the externally driven pump 8 may be driven until a predetermined time has elapsed after the engine 2 is stopped, and may be stopped after the predetermined time has elapsed.

[0028] The exhaust purification catalyst device 9 is disposed in the exhaust passage 4 downstream of the turbine 5a of the turbocharger 5 in the exhaust direction. A branch path 6a of the blow-by path 6 leading to the exhaust purification catalyst device 9 is connected to the exhaust passage 4 downstream of the turbine 5a of the turbocharger 5 in the exhaust direction and upstream of the exhaust purification catalyst device 9 in the exhaust direction. FIG. 1 illustrates an example in which the branch path 6a and the exhaust passage 4 are directly connected, but a valve such as a check valve that prevents exhaust gas from flowing into the branch path 6a may be provided between the branch path 6a and the exhaust passage 4. The exhaust purification catalyst device 9 operates in response to the operation of the engine 2, and is activated by warming up the catalyst. The exhaust purification catalyst device 9 purifies the exhaust gas flowing through the exhaust passage 4 by catalytic reduction, and the exhaust purification catalyst device 9 as a treatment device also purifies the blow-by gas flowing through the branch path 6a of the blow-by path 6 by catalytic reduction.

[0029] For example, Fig. 2 shows the relationship between the concentration and mixture ratio of ammonia contained in the blow-by gas input and output to the exhaust purification catalytic device 9. In Fig. 2, the blow-by gas input to the exhaust purification catalytic device 9 is plotted with white circles, and the blow-by gas output from the exhaust purification catalytic device 9 is plotted with black circles. As shown in Fig. 2, regardless of the mixture ratio of ammonia, the concentration of ammonia output can be sufficiently suppressed by the exhaust purification catalytic device 9.

[0030] The abatement device 10 is disposed in the branch path 6b of the blow-by path 6. The abatement device 10 is driven regardless of whether the engine 2 is running (operating) or not, and renders the blow-by gas harmless by removing target substances (toxic substances such as ammonia and methanol) contained in the blow-by gas flowing through the branch path 6b. The branch path 6b is not connected to either the intake path 3 or the exhaust path 4, and discharges the blow-by gas rendered harmless by the abatement device 10. The abatement device 10 is configured, for example, as a gas decomposition type abatement device, a scrubber type abatement device, a combustion abatement type abatement device, or a catalytic decomposition type abatement device.

[0031] Gas decomposition type abatement devices are devices that use decomposition elements to electrically and chemically decompose and remove target substances (toxic substances) in blow-by gas. Gas decomposition type abatement devices consume relatively little power and can be constructed with relatively inexpensive equipment, but they require a neutralizing agent. Scrubber type abatement devices are devices that utilize the solubility of target substances (toxic substances) in water and specific chemical solutions to remove target substances by spraying cleaning solutions such as water and sulfuric acid into the blow-by gas. Scrubber type abatement devices can be constructed with relatively inexpensive equipment, but the equipment size is large.

[0032] In addition, the combustion abatement type abatement device is a device that decomposes and abats target substances (toxic substances) by burning the blow-by gas with a burner or the like to heat it up. The combustion abatement type abatement device is suitable for abating high concentrations of target substances, but it consumes a lot of power, incurs fuel costs, and is large in equipment size. The catalytic decomposition type abatement device is a device that abats target substances at low temperatures by utilizing a catalyst that promotes the reduction and decomposition of target substances (toxic substances) contained in the blow-by gas. The catalytic decomposition type abatement device can abating target substances at relatively low temperatures, but the equipment size is large, the equipment is expensive, and the running costs increase. In the engine system 1, an appropriate abatement device 10 is applied after taking into consideration the advantages and disadvantages as described above.

[0033] The intake air return device 11 returns the blow-by gas to the intake passage 3 through the branch passage 6c of the blow-by passage 6. The branch passage 6c is connected to the intake passage 3 upstream of the compressor 5b of the turbocharger 5 in the intake direction. FIG. 1 illustrates an example in which the branch passage 6c and the intake passage 3 are directly connected, but a valve such as a check valve that prevents the intake air from flowing into the branch passage 6c may be provided between the branch passage 6c and the intake passage 3. In other words, the intake air return device 11 is configured by the branch passage 6c and a part of the intake passage 3 from the branch passage 6c to the turbocharger 5, and processes the blow-by gas by mixing the blow-by gas flowing through the branch passage 6c with the air or mixture flowing through the intake passage 3. The intake passage 3 and the turbocharger 5 operate in response to the operation of the engine 2 to supply the mixture to the engine 2, so the intake air return device 11 also operates in response to the operation of the engine 2 to return the blow-by gas to the intake passage 3.

[0034] The control unit 13 is a computer such as an ECU (Engine Control Unit) that controls the operation of the engine 2, and includes a CPU, ROM, RAM, etc., and is configured to control each part of the engine 2. The control unit 13 may store various programs for controlling the engine 2, and control the engine 2 by reading and executing the programs.

[0035] In particular, the control unit 13 controls the path switching valve 12 in accordance with the state of the engine 2 and the plurality of processing devices to switch to one of the plurality of branch paths 6a, 6b, and 6c, thereby switching the processing device that processes the blow-by gas among the plurality of processing devices. Fig. 3 shows examples of processing devices that are used in accordance with the state of the engine 2. In Fig. 3, the processing device that is used as the main processing device is shown by a black circle, the processing device that is used as a backup in case of a malfunction of the main processing device is shown by a white circle, and the processing device that is not used regardless of the engine 2 is shown by a cross.

[0036] Specifically, the control unit 13 monitors whether the engine 2 is operating or stopped. When the engine 2 is operating, the control unit 13 normally controls the exhaust gas purification catalyst device 9 to treat the blow-by gas, i.e., switches the route of the blow-by gas to the branch route 6a by the route switching valve 12.

[0037] On the other hand, even when the engine 2 is in operation, if an abnormality occurs in the treatment of blow-by gas by the exhaust purification catalyst device 9, the control unit 13 controls the treatment of the blow-by gas to be switched from the exhaust purification catalyst device 9 to the detoxification device 10 or the intake air reduction device 11, that is, the path of the blow-by gas is switched to the branch path 6b or 6c by the path switching valve 12. In other words, while the engine 2 is in operation, the control unit 13 mainly uses the exhaust purification catalyst device 9, and uses the detoxification device 10 and the intake air reduction device 11 as backups depending on the state of the engine 2 and multiple treatment devices. At this time, the control unit 13 controls the use of the detoxification device 10 in preference to the intake air reduction device 11, and may control the treatment of the blow-by gas to be switched from the detoxification device 10 to the intake air reduction device 11 if an abnormality occurs in the detoxification device 10.

[0038] For example, in order to determine whether or not an abnormality has occurred in the treatment of blow-by gas by the exhaust purification catalytic device 9, the control unit 13 may monitor whether or not the exhaust purification catalytic device 9 is operating in conjunction with the operation of the engine 2, and may determine that an abnormality has occurred in the treatment of blow-by gas when the exhaust purification catalytic device 9 is not operating. Alternatively, the engine device 1 may be provided with a sensor that detects harmful substances such as ammonia and methanol contained in the exhaust gas from the exhaust purification catalytic device 9. Then, based on the detection result of the sensor, the control unit 13 may determine that an abnormality has occurred in the treatment of blow-by gas when harmful substances equal to or greater than a predetermined threshold value are detected.

[0039] Furthermore, even when the engine 2 is in operation, if the exhaust gas purification catalyst device 9 is not sufficiently treating the blow-by gas, the control unit 13 controls the treatment of the blow-by gas to be switched from the exhaust gas purification catalyst device 9 to the abatement device 10 or the intake air reduction device 11, that is, switches the route of the blow-by gas to the branch route 6b or 6c by the route switching valve 12. At this time, the control unit 13 controls the use of the abatement device 10 in preference to the intake air reduction device 11, and may control the treatment of the blow-by gas to be switched from the abatement device 10 to the intake air reduction device 11 if an abnormality occurs in the abatement device 10.

[0040] For example, in order to determine whether or not the treatment of blow-by gas by the exhaust purification catalytic device 9 is sufficient, the engine device 1 is provided with a torque sensor that detects the load (torque) of the engine 2 and a temperature sensor that detects the temperature of exhaust gas flowing through the exhaust passage 4. Then, based on the detection results of the torque sensor and the temperature sensor, the control unit 13 may determine that the treatment of blow-by gas is insufficient when it detects a decrease in exhaust gas temperature (e.g., a decrease below a predetermined temperature threshold) associated with a decrease in the load of the engine 2 (e.g., a decrease below a predetermined torque threshold).

[0041] Furthermore, when the engine 2 is stopped, the control unit 13 controls the processing of the blow-by gas to be switched from the exhaust purification catalyst device 9 to the abatement device 10, that is, the path switching valve 12 switches the path of the blow-by gas to the branch path 6b. In other words, after the engine 2 is stopped, the control unit 13 mainly uses the exhaust purification catalyst device 9, and uses the abatement device 10 as a backup depending on the state of the engine 2 and the multiple treatment devices.

[0042] In addition, when the engine 2 is stopped in an emergency, the control unit 13 preferably uses the abatement device 10 as the main device, and uses the exhaust purification catalyst device 9 as a backup device depending on the state of the engine 2 and the multiple treatment devices.

[0043] As described above, according to this embodiment, the engine device 1 is an engine device 1 that runs on fuel containing toxic substances, and includes a plurality of treatment devices (exhaust gas purification catalyst device 9, abatement device 10, and intake reduction device 11) with different functions as devices for treating blow-by gas generated in the crankcase 22, and a path switching valve 12 that switches to a treatment device that treats the blow-by gas among the plurality of treatment devices. The abatement device 10 of the treatment device is a gas decomposition type abatement device, a scrubber type abatement device, a combustion abatement type abatement device, or a catalytic decomposition type abatement device. The toxic substance contained in the fuel is ammonia or methanol.

[0044] As a result, even if an abnormality occurs in one of the processing devices that process blow-by gas, that is, even if a single abnormality occurs, the engine system 1 can process the blow-by gas by switching to another processing device. Therefore, the processing of blow-by gas containing toxic substances does not depend on a single means, and even if a single abnormality occurs, it is possible to prevent the toxic substances contained in the blow-by gas from leaking to the outside, thereby contributing to improved safety.

[0045] Moreover, according to this embodiment, the engine device 1 includes the blow-by path 6 connected to the crankcase 22 and the externally driven pump 8 that causes the blow-by gas to flow in the blow-by path 6.

[0046] As a result, even when the engine 2 stops operating, the engine device 1 uses the externally driven pump 8 to ventilate the crankcase 22 and create a negative pressure in the crankcase 22. Therefore, even when the engine 2 is stopped, it is possible to detoxify toxic substances in the blow-by gas remaining in the crankcase 22, suppress the risk of contamination of the surrounding environment, and contribute to improved safety.

[0047] More specifically, according to this embodiment, the engine unit 1 includes a blow-by path 6 connected to the crankcase 22, and an externally driven pump 8 that causes the blow-by gas to flow in the blow-by path 6, and further includes an exhaust purification catalyst device 9, a detoxification device 10, and an intake reduction device 11 as multiple treatment devices.

[0048] As a result, the engine system 1 can treat blow-by gas by selectively switching between the exhaust purification catalyst device 9, the detoxification device 10, and the intake reduction device 11 as appropriate, depending on the state of the engine 2 and each treatment device.

[0049] Furthermore, according to this embodiment, during engine operation, the engine device 1 normally processes blow-by gas using the exhaust purification catalyst device 9, but if an abnormality occurs in the processing of blow-by gas by the exhaust purification catalyst device 9, the processing of the blow-by gas is switched from the exhaust purification catalyst device 9 to the decontamination device 10 or the intake reduction device 11.

[0050] As a result, even if an abnormality occurs in the exhaust purification catalytic device 9, the engine device 1 can smoothly process the blow-by gas by the detoxification device 10 or the intake reduction device 11.

[0051] Alternatively, according to this embodiment, during engine operation, the engine system 1 normally processes blow-by gas using the exhaust purification catalyst device 9, but if the processing of blow-by gas by the exhaust purification catalyst device 9 is insufficient, the processing of blow-by gas is switched from the exhaust purification catalyst device 9 to the decontamination device 10 or the intake reduction device 11.

[0052] As a result, even if the exhaust purification catalyst device 9 is unable to sufficiently treat the blow-by gas due to a change or abnormality in the operating condition of the engine 2 other than that of the exhaust purification catalyst device 9, such as a decrease in the load on the engine 2 or a drop in the exhaust gas temperature, the engine device 1 can smoothly treat the blow-by gas using the decontamination device 10 or the intake reduction device 11.

[0053] Alternatively, according to this embodiment, the engine device 1 treats blow-by gas using the exhaust purification catalyst device 9 while the engine 2 is operating, and when the engine 2 is stopped, the treatment of the blow-by gas is switched from the exhaust purification catalyst device 9 to the decontamination device 10.

[0054] As a result, even if the engine 2 is stopped and the exhaust gas purification catalyst device 9 or the intake air return device 11 cannot process the blow-by gas, the engine device 1 can process the blow-by gas smoothly using the decontamination device 10. By suppressing the processing of the blow-by gas using the intake air return device 11, the intake system components such as the intake passage 3 and the compressor 5b of the turbocharger 5 can be prevented from being contaminated by the blow-by gas, and the replacement interval of the intake system components can be extended. In addition, the intake system components can be configured without adopting corrosion-resistant members or corrosion-resistant coatings against the blow-by gas, so that an increase in the cost of the intake system components can be suppressed, and a decrease in the marketability of the intake system components can be suppressed.

[0055] In the above embodiment, an example has been described in which the engine device 1 includes the exhaust purification catalytic device 9, the abatement device 10, and the intake reduction device 11 as a plurality of treatment devices, but the present invention is not limited to this example.

[0056] In the first modified example, the engine system 1 does not include an intake return device 11, but includes an exhaust gas purification catalyst device 9 and abatement device 10 as the multiple treatment devices. In the first modified example, similarly to the above-described embodiment, the control unit 13 controls the path switching valve 12 in accordance with the state of the engine 2 and the multiple treatment devices to switch to one of the multiple branch paths 6a and 6b, thereby switching the treatment device that performs the treatment of the blow-by gas to the exhaust gas purification catalyst device 9 or the abatement device 10. As a result, the engine system 1 can treat the blow-by gas by appropriately and selectively switching to the exhaust gas purification catalyst device 9 or the abatement device 10 in accordance with the state of the engine 2 and each treatment device.

[0057] Since the intake return device 11 does not process blow-by gas, it is possible to prevent the intake passage 3, the compressor 5b of the turbocharger 5, and other intake system components from being contaminated by blow-by gas, and to lengthen the replacement interval of the intake system components. Also, since the intake system components can be configured without using corrosion-resistant materials or corrosion-resistant coatings against blow-by gas, it is possible to prevent an increase in the cost of the intake system components and a decrease in the product appeal of the intake system components.

[0058] Specifically, also in the first modified example, when the engine 2 is in operation, the control unit 13 normally controls the exhaust gas purification catalyst device 9 to treat the blow-by gas.

[0059] On the other hand, even when the engine 2 is in operation, if an abnormality occurs in the treatment of blow-by gas by the exhaust purification catalyst device 9, the control unit 13 controls to switch the treatment of blow-by gas from the exhaust purification catalyst device 9 to the abatement device 10. In other words, while the engine 2 is in operation, the control unit 13 mainly uses the exhaust purification catalyst device 9, and uses the abatement device 10 as a backup depending on the state of the engine 2 and the multiple treatment devices. As a result, the engine system 1 can smoothly treat the blow-by gas by the abatement device 10 even if an abnormality occurs in the exhaust purification catalyst device 9.

[0060] Furthermore, even when the engine 2 is in operation, if the exhaust gas purification catalyst device 9 is not sufficiently treating the blow-by gas, the control unit 13 controls to switch the treatment of the blow-by gas from the exhaust gas purification catalyst device 9 to the abatement device 10. As a result, the engine device 1 can smoothly treat the blow-by gas by the abatement device 10 even if the exhaust gas purification catalyst device 9 is not sufficiently treating the blow-by gas due to a change or abnormality in the operating state of the engine 2 other than the exhaust gas purification catalyst device 9, such as a drop in the load of the engine 2 or a drop in the temperature of the exhaust gas.

[0061] Furthermore, in the first modified example as well, when the engine 2 is stopped, the control unit 13 controls to switch the processing of the blow-by gas from the exhaust purification catalyst device 9 to the abatement device 10. As a result, even if the exhaust purification catalyst device 9 is unable to process the blow-by gas due to the stop of the engine 2, the engine device 1 can process the blow-by gas smoothly using the abatement device 10. Note that, in the first modified example as well, when the engine 2 is stopped in an emergency, the control unit 13 preferably mainly uses the abatement device 10 and uses the exhaust purification catalyst device 9 as a backup depending on the state of the engine 2 and the multiple processing devices.

[0062] Alternatively, in the second modified example, the engine system 1 does not include the abatement device 10, but includes an exhaust gas purification catalyst device 9 and an intake air reduction device 11 as the multiple treatment devices. In the second modified example, as in the above-described embodiment, the control unit 13 controls the path switching valve 12 according to the state of the engine 2 and the multiple treatment devices, and switches to one of the multiple branch paths 6a and 6c, thereby switching the treatment device that performs the treatment of the blow-by gas to the exhaust gas purification catalyst device 9 or the intake air reduction device 11. As a result, the engine system 1 can treat the blow-by gas by appropriately and selectively switching to the exhaust gas purification catalyst device 9 or the intake air reduction device 11 according to the state of the engine 2 and each treatment device.

[0063] Specifically, also in the second modified example, when the engine 2 is in operation, the control unit 13 normally controls the exhaust gas purification catalyst device 9 to treat the blow-by gas.

[0064] On the other hand, even when the engine 2 is in operation, if an abnormality occurs in the processing of blow-by gas by the exhaust purification catalyst device 9, the control unit 13 controls to switch the processing of blow-by gas from the exhaust purification catalyst device 9 to the intake air reduction device 11. In other words, while the engine 2 is in operation, the control unit 13 mainly uses the exhaust purification catalyst device 9, and uses the intake air reduction device 11 as a backup depending on the state of the engine 2 and multiple processing devices. As a result, the engine system 1 can smoothly process blow-by gas by the intake air reduction device 11 even if an abnormality occurs in the exhaust purification catalyst device 9.

[0065] Furthermore, even when the engine 2 is in operation, if the exhaust gas purification catalyst device 9 is not sufficiently treating the blow-by gas, the control unit 13 controls to switch the treatment of the blow-by gas from the exhaust gas purification catalyst device 9 to the intake air reduction device 11. As a result, the engine device 1 can smoothly treat the blow-by gas by the intake air reduction device 11 even if the exhaust gas purification catalyst device 9 is not sufficiently treating the blow-by gas due to a change or abnormality in the operating state of the engine 2 other than that of the exhaust gas purification catalyst device 9, such as a drop in the load of the engine 2 or a drop in the temperature of the exhaust gas.

[0066] Furthermore, in the second modified example, since the intake reduction device 11 does not operate when the engine 2 is stopped, the control unit 13 may perform control so as to maintain the processing of blow-by gas in the exhaust purification catalyst device 9. Similarly, in the second modified example, since the intake reduction device 11 does not operate when the engine 2 is stopped in an emergency, the control unit 13 may mainly use the exhaust purification catalyst device 9.

[0067] In addition, the present invention can be modified as appropriate within the scope that does not contradict the gist or concept of the invention that can be read from the claims and the entire specification, and engine devices involving such modifications are also included in the technical concept of the present invention.

[0068] [Appendix to the invention] The following will provide an overview of the invention extracted from the above-described embodiment. Note that the configurations and processing functions described in the following supplementary notes can be selected and combined as desired.

[0069] <Appendix 1> An engine device that runs on a fuel containing a toxic substance, As a device for treating blow-by gas, a plurality of treatment devices having different functions are provided; and a path switching valve that switches to the treatment device that performs treatment of the blow-by gas, among the plurality of treatment devices.

[0070] <Appendix 2> 2. The engine device according to claim 1, further comprising an externally driven pump for causing the blow-by gas to flow through a blow-by passage.

[0071] <Appendix 3> 3. The engine device according to claim 2, wherein the plurality of treatment devices include an exhaust gas purification catalyst device and a detoxification device.

[0072] <Appendix 4> 4. The engine system according to claim 3, characterized in that, when an abnormality occurs in the treatment of the blow-by gas by the exhaust purification catalyst device during engine operation, the treatment of the blow-by gas is switched from the exhaust purification catalyst device to the abatement device.

[0073] <Appendix 5> 5. An engine system according to claim 3 or 4, characterized in that, when the treatment of the blow-by gas by the exhaust purification catalyst device is insufficient during engine operation, the treatment of the blow-by gas is switched from the exhaust purification catalyst device to the abatement device.

[0074] <Appendix 6> An engine device according to any one of claims 3 to 5, characterized in that while the engine is operating, the blow-by gas is treated by the exhaust purification catalyst device, and when the engine is stopped, the blow-by gas is treated by switching from the exhaust purification catalyst device to the abatement device.

[0075] <Appendix 7> 3. The engine device according to claim 2, wherein the plurality of treatment devices include an exhaust gas purification catalyst device and an intake air reduction device.

[0076] <Appendix 8> 8. The engine device according to claim 7, characterized in that, when an abnormality occurs in the treatment of the blow-by gas by the exhaust purification catalyst device during engine operation, the treatment of the blow-by gas is switched from the exhaust purification catalyst device to the intake air reduction device.

[0077] <Appendix 9> 9. The engine system according to claim 7 or 8, characterized in that, when the treatment of the blow-by gas by the exhaust purification catalyst device is insufficient during engine operation, the treatment of the blow-by gas is switched from the exhaust purification catalyst device to the intake air reduction device.

[0078] <Appendix 10> 3. The engine device according to claim 2, wherein the plurality of treatment devices include an exhaust gas purification catalyst device, a detoxification device, and an intake air reduction device.

[0079] <Appendix 11> 11. The engine system according to claim 10, characterized in that, when an abnormality occurs in the treatment of the blow-by gas by the exhaust purification catalyst device during engine operation, the treatment of the blow-by gas is switched from the exhaust purification catalyst device to the abatement device or the intake reduction device.

[0080] <Appendix 12> 12. An engine system according to claim 10 or 11, characterized in that, when the treatment of the blow-by gas by the exhaust purification catalyst device is insufficient during engine operation, the treatment of the blow-by gas is switched from the exhaust purification catalyst device to the abatement device or the intake reduction device.

[0081] <Appendix 13> 13. The engine device according to any one of claims 10 to 12, characterized in that while the engine is operating, the blow-by gas is treated by the exhaust purification catalyst device, and when the engine is stopped, the blow-by gas is treated by switching from the exhaust purification catalyst device to the abatement device.

[0082] <Appendix 14> 14. The engine system according to any one of claims 3 to 6 and claims 10 to 13, wherein the abatement device is a gas decomposition type abatement device, a scrubber type abatement device, a combustion abatement type abatement device, or a catalytic decomposition type abatement device.

[0083] <Appendix 15> 15. The engine device according to any one of claims 1 to 14, wherein the toxic substance is ammonia or methanol. [Explanation of symbols]

[0084] 1 Engine unit 2 Engine 3 Intake passage 4 Exhaust passage 5. Turbocharger 5a Turbine 5b Compressor 6 Blow-by path 6a, 6b, 6c Branching Path 7 Filters 8 Externally driven pump 9. Exhaust gas purification catalyst device 10 Abatement equipment 11. Intake reduction device 12. Path switching valve 13. Control Unit 20 Cylinder block 21 cylinders 21a Combustion chamber 22 Crankcase 23 Cylinder 24 Piston 25 Cylinder head 26 Crankshaft 27 Connecting rod

Claims

1. An engine device that runs on a fuel containing a toxic substance, As a device for treating blow-by gas, a plurality of treatment devices having different functions are provided; and a path switching valve that switches to the treatment device that performs treatment of the blow-by gas, among the plurality of treatment devices.

2. 2. The engine apparatus according to claim 1, further comprising an externally driven pump for causing the blow-by gas to flow through the blow-by passage.

3. 3. The engine system according to claim 2, wherein the plurality of treatment devices include an exhaust gas purification catalyst device and an abatement device.

4. 4. The engine system according to claim 3, wherein, when an abnormality occurs in the treatment of the blow-by gas by the exhaust gas purification catalyst device during engine operation, the treatment of the blow-by gas is switched from the exhaust gas purification catalyst device to the abatement device.

5. 4. The engine system according to claim 3, wherein, when the treatment of the blow-by gas by the exhaust gas purification catalyst device is insufficient during engine operation, the treatment of the blow-by gas is switched from the exhaust gas purification catalyst device to the abatement device.

6. 4. The engine system according to claim 3, wherein the blow-by gas is treated by the exhaust gas purification catalyst device while the engine is operating, and the blow-by gas is treated by switching from the exhaust gas purification catalyst device to the abatement device when the engine is stopped.

7. 3. The engine system according to claim 2, wherein the plurality of treatment devices include an exhaust gas purification catalyst device and an intake air reduction device.

8. 8. The engine system according to claim 7, wherein, when an abnormality occurs in the processing of the blow-by gas by the exhaust purification catalyst device during engine operation, the processing of the blow-by gas is switched from the exhaust purification catalyst device to the intake reduction device.

9. 8. The engine system according to claim 7, wherein, when the blow-by gas is not sufficiently treated by the exhaust gas purification catalyst device during engine operation, the treatment of the blow-by gas is switched from the exhaust gas purification catalyst device to the intake air reduction device.

10. 3. The engine system according to claim 2, wherein the plurality of treatment devices include an exhaust gas purification catalyst device, a detoxification device, and an intake air reduction device.

11. 11. The engine system according to claim 10, wherein, when an abnormality occurs in the treatment of the blow-by gas by the exhaust purification catalyst device during engine operation, the treatment of the blow-by gas is switched from the exhaust purification catalyst device to the abatement device or the intake reduction device.

12. 11. The engine system according to claim 10, wherein, when the treatment of the blow-by gas by the exhaust purification catalyst device is insufficient during engine operation, the treatment of the blow-by gas is switched from the exhaust purification catalyst device to the abatement device or the intake reduction device.

13. 11. The engine system according to claim 10, wherein the blow-by gas is treated by the exhaust gas purification catalyst device while the engine is operating, and the blow-by gas is treated by switching from the exhaust gas purification catalyst device to the abatement device when the engine is stopped.

14. 11. The engine system according to claim 3 or 10, wherein the abatement device is a gas decomposition type abatement device, a scrubber type abatement device, a combustion abatement type abatement device or a catalytic decomposition type abatement device.

15. 2. The engine apparatus according to claim 1, wherein the toxic substance is ammonia or methanol.

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