Engine System

Abstract

To lower a concentration of moisture included in oil stored in an oil storage part.SOLUTION: An engine system 100 includes an internal combustion engine 10, a hydrogen generator 50, and a heat exchange mechanism 70. The internal combustion engine 10 is an internal combustion engine using hydrogen as fuel. The internal combustion engine 10 has an oil pan 25 storing oil. The hydrogen generator 50 generates hydrogen by heating a material of hydrogen. The heat exchange mechanism 70 exchanges heat between the hydrogen generator 50 and the oil that is stored in the oil pan 25.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to engine systems. [Background technology]

[0002] The engine system of Patent Document 1 includes an internal combustion engine and a hydrogen generator. The internal combustion engine uses hydrogen as fuel. The hydrogen generator generates hydrogen from water by electrolysis. The hydrogen generated by the hydrogen generator is then supplied to the internal combustion engine as fuel. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] US Patent Application Publication No. 2018 / 0112608 Summary of the Invention [Problem to be solved by the invention]

[0004] In an engine system such as that described in Patent Document 1, water is generated when hydrogen is burned in the cylinders of the internal combustion engine. Some of the generated water is then mixed with the oil stored in the oil storage unit of the internal combustion engine. If the concentration of water contained in the oil in the oil storage unit becomes excessively high, there is a risk that the oil will deteriorate. [Means for solving the problem]

[0005] An engine system for solving the above problem includes an internal combustion engine that uses hydrogen as fuel and has an oil storage unit that stores oil, a hydrogen generation device that generates hydrogen by heating a raw material for the hydrogen, and a heat exchange mechanism that exchanges heat between the hydrogen generation device and the oil stored in the oil storage unit.

[0006] According to the above configuration, when the hydrogen generator is driven, heat from the hydrogen generator is transferred to the oil stored in the oil storage unit, raising the temperature of the oil, which causes the moisture contained in the oil to evaporate, thereby reducing the moisture concentration in the oil. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 2 is a schematic configuration diagram of an engine system. [Figure 2] 10 is a flowchart showing moisture suppression control. DETAILED DESCRIPTION OF THE INVENTION

[0008] <Outline of engine system configuration> An embodiment of the present invention will now be described with reference to Figures 1 and 2. First, the schematic configuration of an engine system 100 will be described.

[0009] As shown in Fig. 1, the engine system 100 includes an internal combustion engine 10. The internal combustion engine 10 is an internal combustion engine that uses hydrogen as fuel. The internal combustion engine 10 includes a head cover 21, a cylinder head 22, a cylinder block 23, a crankcase 24, and an oil pan 25. The internal combustion engine 10 also includes a plurality of pistons 31, a plurality of connecting rods 32, a crankshaft 33, an intake pipe 41, and an exhaust pipe 42.

[0010] The cylinder block 23 has four cylinders 23A and four upper spaces 23B as internal spaces of the cylinder block 23. The cylinders 23A extend from the upper end of the cylinder block 23 to near the center in the vertical direction. The cylinders 23A are spaces for burning a mixture of fuel and intake air. The upper spaces 23B extend from the lower ends of the cylinders 23A to the lower end of the cylinder block 23. Pistons 31 are located inside the cylinders 23A. The pistons 31 are connected to a crankshaft 33 via connecting rods 32. The pistons 31 reciprocate inside the cylinders 23A as the mixture of fuel and intake air burns in the cylinders 23A. The reciprocating motion of the pistons 31 rotates the crankshaft 33. Note that FIG. 1 shows only one cylinder 23A as a representative.

[0011] The crankcase 24 is connected to the lower end of the cylinder block 23. The crankcase 24 has a so-called ladder frame structure. Therefore, the crankcase 24 has four lower spaces 24A as internal spaces. The lower spaces 24A extend from the upper end to the lower end of the crankcase 24. The lower spaces 24A are connected to the lower ends of the upper spaces 23B. The cylinder block 23 and the crankcase 24 support the crankshaft 33 sandwiched between them. The upper spaces 23B of the cylinder block 23 and the lower spaces 24A of the crankcase 24 function as a crank chamber that houses the crankshaft 33.

[0012] The oil pan 25 is connected to the lower end of the crankcase 24. The oil pan 25 is shaped like a generally rectangular box with a bottom. Therefore, the oil pan 25 has an oil chamber 25A as an internal space of the oil pan 25. The oil chamber 25A stores oil. The oil in the oil chamber 25A is supplied to each part of the internal combustion engine 10 by a pump (not shown). In this embodiment, the oil pan 25 is an example of an oil storage part.

[0013] The cylinder head 22 is connected to the upper end of the cylinder block 23. The cylinder head 22 has four intake ports 22A, four exhaust ports 22B, and four combustion recesses 22C as an internal space of the cylinder head 22. The combustion recesses 22C are recessed upward from the lower surface of the cylinder head 22. The combustion recesses 22C are connected to the upper ends of the cylinders 23A. The combustion recesses 22C, the cylinders 23A, and the pistons 31 define a combustion chamber.

[0014] A first end of the intake port 22A is connected to the combustion recess 22C. A second end of the intake port 22A opens to a side surface of the cylinder head 22. An intake pipe 41 is connected to the second end of the intake port 22A. The intake pipe 41 introduces intake air from outside the internal combustion engine 10 into the intake port 22A. The intake port 22A introduces the intake air that has flowed through the intake pipe 41 into the cylinder 23A.

[0015] A first end of the exhaust port 22B is connected to the combustion recess 22C. A second end of the exhaust port 22B opens to a side surface of the cylinder head 22. An exhaust pipe 42 is connected to the second end of the exhaust port 22B. The exhaust port 22B discharges exhaust gas from the cylinder 23A to the exhaust pipe 42. The exhaust pipe 42 discharges the exhaust gas that has flowed through the exhaust port 22B to the outside of the internal combustion engine 10.

[0016] The head cover 21 is connected to the upper end of the cylinder head 22. The head cover 21 covers the cylinder head 22. The head cover 21, together with the cylinder head 22, defines an accommodation space 21A. The accommodation space 21A accommodates a valve mechanism and the like (not shown).

[0017] The internal combustion engine 10 includes a plurality of intake valves 34, a plurality of exhaust valves 35, a plurality of fuel injection valves 36, a plurality of ignition devices 37, and a throttle valve 38. The intake valve 34 is located at the connection between the intake port 22A and the combustion recess 22C. The intake valve 34 opens and closes the downstream end of the intake port 22A by driving force from a valve mechanism (not shown). The exhaust valve 35 is located at the connection between the exhaust port 22B and the combustion recess 22C. The exhaust valve 35 opens and closes the upstream end of the exhaust port 22B by driving force from a valve mechanism (not shown).

[0018] The throttle valve 38 is located midway through the intake pipe 41. The throttle valve 38 adjusts the amount of intake air flowing through the intake pipe 41. The tip of the fuel injection valve 36 is located midway through the intake port 22A. The fuel injection valve 36 injects hydrogen as fuel into the intake port 22A. As a result, hydrogen is supplied to the cylinder 23A via the intake port 22A and the combustion recess 22C. The tip of the ignition device 37 is located in the combustion recess 22C. The ignition device 37 ignites the mixture of fuel and intake air by spark discharge.

[0019] The engine system 100 includes a motor generator 60 and a battery 65. The motor generator 60 is connected to the crankshaft 33 of the internal combustion engine 10. Therefore, the motor generator 60 can generate electric power using the driving force from the crankshaft 33 of the internal combustion engine 10. The battery 65 can store the electric power generated by the motor generator 60.

[0020] The engine system 100 includes a hydrogen generator 50, a supply passage 56, and a fuel tank 57. One example of the hydrogen generator 50 is a device that generates hydrogen from biomass. The hydrogen generator 50 includes a reactor 51 and a heater 52. The reactor 51 generates hydrogen from a hydrogen raw material accommodated in the reactor 51. Here, the hydrogen raw material is, for example, woody biomass. The heater 52 is capable of heating the hydrogen raw material accommodated in the reactor 51. The hydrogen generator 50 generates hydrogen, for example, as follows. First, the heater 52 heats the woody biomass accommodated in the reactor 51 to approximately 800°C to 1000°C. Then, the woody biomass in the reactor 51 is gasified. This gas contains, for example, ethanol gas, methanol gas, etc. Then, the reactor 51 generates hydrogen by reforming the gas. That is, the hydrogen generator 50 is a device that generates hydrogen by heating the hydrogen raw material. The configuration of the hydrogen generator 50 is well known. For example, the configuration of the hydrogen generator 50 is described in JP 2019-026503 A, JP 2019-041681 A, etc.

[0021] A first end of the supply passage 56 is connected to the hydrogen generator 50. A second end of the supply passage 56 is connected to the fuel injection valve 36. A fuel tank 57 is located midway along the supply passage 56. The fuel tank 57 is capable of storing hydrogen. Therefore, the hydrogen generated by the hydrogen generator 50 is temporarily stored in the fuel tank 57. The hydrogen stored in the fuel tank 57 is then supplied to the fuel injection valve 36 via the supply passage 56 on the fuel injection valve 36 side as viewed from the fuel tank 57. Although not shown, a regulator or the like is provided in the portion of the supply passage 56 on the fuel injection valve 36 side as viewed from the fuel tank 57 to reduce the pressure of the hydrogen fuel.

[0022] The engine system 100 includes a heat exchange mechanism 70. The heat exchange mechanism 70 includes a circulation passage 71 and an oil pump 72. The oil pump 72 pumps oil drawn in through an intake port and pumps it out of a discharge port. In this embodiment, the oil pump 72 is an electric pump driven by an electric motor (not shown), a so-called electric oil pump.

[0023] The upstream end of the circulation passage 71 is connected to the discharge port of the oil pump 72. The downstream end of the circulation passage 71 is connected to the suction port of the oil pump 72. That is, the oil pump 72 can pump the oil in the circulation passage 71. A portion of the circulation passage 71 is located inside the hydrogen generator 50. Specifically, a portion of the circulation passage 71 is located near the reactor 51 and the heater 52 in the hydrogen generator 50. Therefore, the oil in the portion of the circulation passage 71 located near the reactor 51 and the heater 52 in the hydrogen generator 50 is warmed by the reactor 51 and the heater 52. The oil pan 25 also forms a portion of the circulation passage 71. The oil pan 25 is located downstream of the circulation passage 71 as viewed from the hydrogen generator 50. Therefore, the oil that has circulated near the reactor 51 and the heater 52 in the hydrogen generator 50 flows into the oil pan 25. Then, the oil inside the oil pan 25 flows out to the oil pump 72. In other words, the oil in the circulation passage 71 circulates through the oil pump 72, the hydrogen generator 50, and the oil pan 25 in that order. That is, the circulation passage 71 is a passage for circulating the oil between the oil pan 25 and the hydrogen generator 50. In this embodiment, the heat exchange mechanism 70 exchanges heat between the hydrogen generator 50 and the oil stored in the oil pan 25 by circulating the oil as described above.

[0024] 1, the engine system 100 includes a water concentration sensor 81 and a control device 90. The water concentration sensor 81 detects a water concentration MC, which is the concentration of water contained in the oil stored in the oil pan 25. The control device 90 acquires a signal indicating the water concentration MC from the water concentration sensor 81.

[0025] The control device 90 controls the internal combustion engine 10, the hydrogen generation device 50, the motor generator 60, and the heat exchange mechanism 70. Specifically, the control device 90 performs various controls such as adjusting the amount of fuel injected from the fuel injection valve 36, adjusting the ignition timing of the ignition device 37, and adjusting the opening of the throttle valve 38 by outputting a control signal to the internal combustion engine 10. The control device 90 adjusts the amount of hydrogen generated by the hydrogen generation device 50 by outputting a control signal to the hydrogen generation device 50. The control device 90 adjusts the amount of power generated by the motor generator 60 by outputting a control signal to the motor generator 60. The control device 90 adjusts the amount of oil pumped by the oil pump 72 by outputting a control signal to the heat exchange mechanism 70.

[0026] The control device 90 may be configured as a circuit including one or more processors that execute various processes according to a computer program (software). The control device 90 may also be configured as a circuit including one or more dedicated hardware circuits, such as an application-specific integrated circuit (ASIC), that execute at least some of the various processes, or a combination thereof. The processor includes a CPU and memory such as RAM and ROM. The memory stores program code or instructions configured to cause the CPU to execute processes. The memory, i.e., computer-readable medium, includes any medium that can be accessed by a general-purpose or dedicated computer.

[0027] <Moisture suppression control> Next, a description will be given of the moisture suppression control executed by the control device 90. In this embodiment, the control device 90 repeatedly executes the moisture suppression control on the condition that the internal combustion engine 10 is stopped.

[0028] As shown in FIG. 2, when the control device 90 starts the water suppression control, it executes the process of step S11. In step S11, the control device 90 determines whether the water concentration MC is equal to or greater than a predetermined threshold A. Here, the threshold A is determined, for example, as follows: First, an upper limit value that can be tolerated for the water concentration MC is determined through experiments or the like. Then, a value that is a certain value lower than the determined upper limit value is determined as the threshold A. In step S11, if the control device 90 determines that the water concentration MC is less than the threshold A (S11: NO), the control device 90 terminates the current water suppression control. On the other hand, if the control device 90 determines in step S11 that the water concentration MC is equal to or greater than the threshold A (S11: YES), the control device 90 proceeds to step S12. In other words, the control device 90 proceeds with the process from step S12 onward on the condition that the water concentration MC contained in the oil stored in the oil pan 25 is equal to or greater than the threshold A and that the internal combustion engine 10 is stopped.

[0029] In step S12, the control device 90 drives the hydrogen generation device 50 by outputting a control signal to the hydrogen generation device 50. Specifically, the control device 90 heats the hydrogen raw material contained in the reactor 51 with the heater 52. If the hydrogen generation device 50 is already driven due to another factor, the control device 90 maintains that state. Thereafter, the control device 90 advances the process to step S13.

[0030] In step S13, the control device 90 drives the oil pump 72 by outputting a control signal to the oil pump 72. As a result, the oil in the circulation passage 71 is circulated by driving the oil pump 72. In this embodiment, the processes of steps S12 and S13 are a circulation process in which the oil is circulated by driving the oil pump 72 while driving the hydrogen generator 50. Thereafter, the control device 90 ends the current water suppression control. Note that in this embodiment, the control device 90 ends the process of step S13 when driving the internal combustion engine 10.

[0031] <Operation of this embodiment> 2, in the engine system 100, the processing from step S12 onwards is executed on the condition that the water concentration MC contained in the oil stored in the oil pan 25 is equal to or higher than the threshold value A and that the internal combustion engine 10 is stopped. Then, in steps S12 and S13, a circulation process is executed to circulate the oil by driving the oil pump 72 while driving the hydrogen generator 50. When the circulation process is executed in this manner, the oil that has circulated near the reactor 51 and the heater 52 in the hydrogen generator 50 flows into the oil pan 25. Then, heat from the reactor 51 and the heater 52 in the hydrogen generator 50 is transferred to the oil stored in the oil pan 25, causing the temperature of the oil to rise.

[0032] <Effects of this embodiment> (1) In the engine system 100, the oil circulates as described above, making it possible to increase the temperature of the oil stored in the oil pan 25. This causes the moisture contained in the oil stored in the oil pan 25 to evaporate. As a result, the moisture concentration MC of the oil stored in the oil pan 25 can be reduced.

[0033] (2) This embodiment employs a heat exchange mechanism 70 having a circulation passage 71 and an oil pump 72. With this configuration, even if there is a certain distance between the internal combustion engine 10 and the hydrogen generator 50, the heat of the hydrogen generator 50 can be efficiently transferred to the oil in the oil pan 25. Furthermore, if a circulation passage 71 connecting the oil pan 25 and the hydrogen generator 50 can be installed, it is possible to realize a heat exchange mechanism 70 that exchanges heat between the hydrogen generator 50 and the oil stored in the oil pan 25. Therefore, when employing the heat exchange mechanism 70, design changes to the internal combustion engine 10 and the hydrogen generator 50 can be kept to a minimum.

[0034] (3) In the present embodiment, the control device 90 executes the circulation process on the condition that the water concentration MC contained in the oil stored in the oil pan 25 is equal to or greater than the threshold value A. According to this configuration, the circulation process is not executed when the water concentration MC is less than the threshold value A. This makes it possible to prevent the circulation process from being executed unnecessarily when the water concentration MC is relatively low. As a result, it is possible to prevent, for example, the consumption of energy for driving the hydrogen generation device 50 and the oil pump 72 due to the execution of the circulation process.

[0035] (4) In this embodiment, the control device 90 executes the circulation process under the condition that the water concentration MC contained in the oil stored in the oil pan 25 is equal to or greater than the threshold value A and that the internal combustion engine 10 is stopped. With this configuration, the circulation process is not executed when the oil temperature is already reasonably high due to the operation of the internal combustion engine 10. In other words, according to this embodiment, the circulation process is not executed when there is little need to increase the oil temperature.

[0036] (5) In the present embodiment, the oil pump 72 is an electric oil pump. Compared to a configuration including, for example, a mechanical oil pump connected to the crankshaft 33, this configuration makes it possible to adjust the amount of oil circulating through the circulation passage 71 regardless of whether the internal combustion engine 10 is running or the rotation speed of the crankshaft 33 of the internal combustion engine 10.

[0037] <Example of change> This embodiment can be modified as follows: This embodiment and the following modifications can be combined and implemented within the scope of technical compatibility.

[0038] In the above embodiment, the moisture suppression control may be changed. For example, the control device 90 may execute the water suppression control regardless of whether the internal combustion engine 10 is stopped or not. According to this configuration, if a positive determination is made in step S11, the circulation process can be executed even if the internal combustion engine 10 is running.

[0039] For example, the process of step S11 may be omitted. That is, the control device 90 may execute the process of step S12 when the moisture suppression control is started. With this configuration, the circulation process can be executed regardless of the moisture concentration MC.

[0040] In the above embodiment, the configuration for acquiring the water concentration MC may be changed. For example, the control device 90 may calculate the water concentration MC based on the integrated value of hydrogen injected from the fuel injection valve 36, the temperature of the oil stored in the oil pan 25, and the like.

[0041] In the above embodiment, the configuration of the engine system 100 may be changed. For example, the oil pump 72 is not limited to an electric oil pump. Specifically, a mechanical oil pump connected to the crankshaft 33 of the internal combustion engine 10 may be used as the oil pump 72. In this case, even when the internal combustion engine 10 is not in operation, if the motor generator 60 is made to function as an electric motor, the mechanical oil pump can be driven by rotating the crankshaft 33.

[0042] The oil storage unit is not limited to the example in the above embodiment. For example, the internal combustion engine 10 may adopt a lubrication system that includes a storage tank for storing oil separate from the oil pan 25, a so-called dry sump system. In this case, the storage tank can be used as the oil storage unit.

[0043] The configuration of the heat exchange mechanism is not limited to the example of the above embodiment. As a specific example, the heat exchange mechanism may include a heat transfer body that transfers heat from the reactor 51 of the hydrogen generator 50. This heat transfer body extends from the outer surface of the reactor 51, and a portion of it is located inside the oil pan 25. The heat transfer body is made of a metal with good thermal conductivity, such as an aluminum alloy. According to this modification, heat from the reactor 51 is transferred to the heat transfer body, causing the heat transfer body to become hot. Then, the oil is heated by contact with the high-temperature heat transfer body or by radiant heat from the high-temperature heat transfer body. Note that although the heat transfer body extending from the reactor 51 has been described as an example, the heat transfer body may also extend from the heater 52.

[0044] Furthermore, for example, a portion of the outer wall of the reactor 51 may be exposed in the oil pan 25. With this configuration, the heat of the reactor 51 is directly transferred to the oil in the oil pan 25. Similarly, a portion of the outer wall of the heater 52 may be exposed in the oil pan 25. In these modified examples, the portion of the reactor 51 exposed in the oil pan 25 or the portion of the heater 52 exposed in the oil pan 25 functions as a heat transfer body.

[0045] The heat exchange mechanism may have both the circulation passage 71 and the oil pump 72 of the above embodiment and the heat transfer body configuration of the above modified example. The hydrogen generator 50 is not limited to the example of the above embodiment. That is, the hydrogen generator 50 may have various configurations as long as it generates hydrogen by heating a hydrogen source.

[0046] <Related technical ideas> The technical ideas that can be understood from the above-described embodiment and modified examples will be described. (Appendix 1) an internal combustion engine that uses hydrogen as fuel and has an oil storage unit that stores oil; a hydrogen generator that generates the hydrogen by heating the hydrogen raw material; a heat exchange mechanism for exchanging heat between the hydrogen generator and the oil stored in the oil storage section. Institutional system.

[0047] (Appendix 2) The hydrogen generation device is a reactor for producing the hydrogen from the hydrogen source; a heater for heating the hydrogen source in the reactor, the heat exchange mechanism has a heat transfer body that transfers heat from one or more selected from the reactor and the heater, A part or all of the heat transfer body is located within the oil reservoir. 1. An engine system as described in Appendix 1.

[0048] (Appendix 3) The heat exchange mechanism includes: a circulation passage for circulating oil between the oil storage unit and the hydrogen generation device; an oil pump that pumps oil through the circulation passage; 1. An engine system according to claim 1 or 2.

[0049] (Appendix 4) a control device that controls the hydrogen generation device and the oil pump; The control device executes a circulation process for circulating oil by driving the oil pump while driving the hydrogen generation device, on the condition that a concentration of water contained in the oil stored in the oil storage unit is equal to or higher than a predetermined threshold. An engine system as described in Appendix 3.

[0050] (Appendix 5) The control device executes the circulation process on the condition that the concentration of water contained in the oil stored in the oil storage section is equal to or higher than the threshold value and the internal combustion engine is stopped. 1. The engine system described in Appendix 4.

[0051] (Appendix 6) The oil pump is an electric oil pump. An engine system according to any one of Supplementary Notes 3 to 5. [Explanation of symbols]

[0052] 10...Internal combustion engine 21...Head cover 22...Cylinder head 23...Cylinder block 24…Crankcase 25...Oil pan 31...Piston 32...Connecting rod 33...Crankshaft 36...Fuel injection valve 41...intake pipe 42...Exhaust pipe 50...Hydrogen generator 51...Reactor 52...heater 56…Supply passage 57...Fuel tank 60...Motor generator 65...Battery 70...Heat exchange mechanism 71...Circulation passage 72...Oil pump 81...Moisture concentration sensor 90...Control device 100...Engine System

Claims

1. an internal combustion engine that uses hydrogen as fuel and has an oil storage unit that stores oil; a hydrogen generator that generates the hydrogen by heating the hydrogen raw material; a heat exchange mechanism that exchanges heat between the hydrogen generator and the oil stored in the oil storage unit, The hydrogen generation device is a reactor for producing the hydrogen from the hydrogen source; a heater for heating the hydrogen source in the reactor, the heat exchange mechanism has a heat transfer body that transfers heat from one or more selected from the reactor and the heater, A part or all of the heat transfer body is located within the oil reservoir. Institutional system.

2. an internal combustion engine that uses hydrogen as fuel and has an oil storage unit that stores oil; a hydrogen generator that generates the hydrogen by heating the hydrogen raw material; a heat exchange mechanism that exchanges heat between the hydrogen generator and the oil stored in the oil storage unit, The heat exchange mechanism includes: a circulation passage for circulating oil between the oil storage unit and the hydrogen generation device; an oil pump that pumps oil through the circulation passage; Institutional system.

3. a control device that controls the hydrogen generation device and the oil pump; The control device executes a circulation process for circulating oil by driving the oil pump while driving the hydrogen generation device, on the condition that a concentration of water contained in the oil stored in the oil storage unit is equal to or higher than a predetermined threshold. The engine system of claim 2 .

4. The control device executes the circulation process on the condition that the concentration of water contained in the oil stored in the oil storage section is equal to or higher than the threshold value and the internal combustion engine is stopped. The engine system of claim 3 .

5. The oil pump is an electric oil pump. An engine system according to any one of claims 2 to 4.

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