Engine device

Abstract

Provided is an engine device equipped with an engine capable of idling and low-load operation using a main fuel containing a low-GHG fuel having a low global warming gas discharge amount while suppressing an increase in product cost. An engine device (1) is provided with a multi-fuel engine (2) that operates by combusting a main fuel containing a low GHG fuel having a lower global warming potential (GHG) discharge amount than a petroleum fuel and a hydrocarbon sub-fuel, and is provided with: a main fuel injection unit (7a) of a fuel injection unit (7) that injects the main fuel by electric power control; a sub-fuel injection unit (7b) of the fuel injection unit (7) that injects sub-fuel by mechanical control; and a control device (8) that performs power control on at least one of the injection amount, injection pressure, injection timing, and injection count of the main fuel by the main fuel injection unit (7a), and that controls the rotational speed of the multi-fuel engine (2) during idle operation.

Description

Technical Field

[0001] The present invention relates to an engine device including a multi-fuel engine that operates by burning a main fuel containing a low-GHG fuel having a lower greenhouse gas emission than petroleum-based fuel and a hydrocarbon-based auxiliary fuel. Background Art

[0002] In the past, there was a structure in an engine device that supplies multiple fuels to an engine that supports multiple fuels, that is, a multi-fuel engine. In order to cope with the main fuel containing low-GHG (Green House Gas) fuels such as ammonia and alcohol that emit less greenhouse gases than petroleum fuels, the multi-fuel engine needs to burn even the main fuel with poor ignition properties. In order to burn this difficult-to-ignite main fuel, the engine device also supplies a hydrocarbon secondary fuel such as light oil, kerosene, and heavy oil with good ignition properties to the multi-fuel engine in addition to the main fuel, thereby enabling the main fuel and the secondary fuel to be burned together.

[0003] For example, Patent Document 1 discloses a fuel injection device for injecting fuel into a cylinder of an internal combustion engine. The fuel injection device includes a main fuel system that injects fuel, and a subsidiary fuel system that injects fuel at a higher pressure than the main fuel system's injection pressure during the initial period of fuel injection. Alternatively, the fuel injection device includes a main fuel system that injects fuel, and a subsidiary fuel system that injects fuel at a higher pressure than the main fuel system's injection pressure during simultaneous injection with the main fuel system.

[0004] According to Patent Document 1, a fuel injection device includes a pressure detection unit that detects the pressure within the cylinder of an internal combustion engine; and a control unit that changes the injection conditions of the auxiliary fuel based on the pressure detected by the pressure detection unit. Alternatively, the fuel injection device includes a control unit that changes the injection conditions of the auxiliary fuel system according to the load conditions of the internal combustion engine, and performs injection of the auxiliary fuel system during low-load operation of the internal combustion engine. Furthermore, according to Patent Document 1, the auxiliary fuel system includes a pressure accumulator that accumulates pressurized fuel, and the internal combustion engine is a diesel engine, and the pressure accumulator includes a common rail.

[0005] In addition, patent document 2 discloses a fuel injection device that injects fuel into the cylinder of an internal combustion engine, which fuel injection device includes: a main fuel injection unit that injects main fuel; a sub-fuel injection unit that injects sub-fuel; and a control unit that injects sub-fuel before injecting the main fuel and controls the sub-fuel injection unit based on changes in initial combustion of the sub-fuel injection.

[0006] According to Patent Document 2, the internal combustion engine is a diesel internal combustion engine. The main fuel injection unit injects the main fuel by mechanical control, and the auxiliary fuel injection unit has a pressure accumulation unit including a common rail for accumulating pressurized fuel and injects the auxiliary fuel by electrical control.

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 2010-133391

[0008] Patent Document 2: Japanese Patent Application Laid-Open No. 2013-036462 Summary of the Invention

[0009] The prior art disclosed in Patent Documents 1 and 2 utilizes a mechanically controlled injection device or a common rail system to supply a main fuel such as ammonia or alcohol to the engine, and a common rail system to supply a secondary fuel such as light oil, kerosene, or heavy fuel oil to the engine. However, utilizing a common rail system for both the main and secondary fuel supply units increases product costs.

[0010] Furthermore, the prior art disclosed in Patent Documents 1 and 2 utilizes a common rail system for the auxiliary fuel supply unit. Therefore, to mitigate product cost increases, a mechanically controlled injection device is employed for the main fuel supply unit. However, compared to common rail systems, mechanically controlled injection devices have limitations in micro-injection, with lower injection pressures and less flexibility in changing the injection timing. Consequently, when using a mechanically controlled injection device to supply the main fuel to the engine, the following problem arises: rotational stability decreases during engine idling, making it impossible to reduce the idle speed. For similar reasons, when using a mechanically controlled injection device to supply the main fuel to the engine, the following problem arises: rotational stability decreases during low-load engine operation.

[0011] To address this problem, conventional engine systems employ a common rail system to operate the engine using auxiliary fuel during idling and low-load operation. However, this restricts the use of low-GHG fuels such as ammonia or alcohol, preventing the reduction of greenhouse gas emissions.

[0012] Furthermore, in general, mechanically controlled injection devices have lower injection pressures than common rail systems. Furthermore, the degree of freedom in changing injection pressure, injection timing, and multi-stage injection is limited. Therefore, if a mechanically controlled injection device is applied to a supply unit for a main fuel having low ignitability and combustion speed, it is difficult to improve the combustion performance of the main fuel, such as atomization and penetration enhancement. Consequently, the usage limits of the main fuel (e.g., usage amount, main fuel co-combustion ratio during co-combustion, etc.) are restricted to a low level.

[0013] An object of the present invention is to provide an engine device having an engine capable of idling and low-load operation using a main fuel containing a low-GHG fuel having low greenhouse gas emissions while suppressing an increase in product cost.

[0014] In order to solve the above-mentioned problems, the engine device of the present invention operates by burning a main fuel containing a low-GHG fuel that emits less greenhouse gases than petroleum fuels and a hydrocarbon auxiliary fuel, and is characterized in that the engine device comprises: a main fuel injection unit that injects the main fuel through electrical control; an auxiliary fuel injection unit that injects the auxiliary fuel through mechanical control; and a control device that electrically controls at least one of the injection amount, injection pressure, injection period and number of injections of the main fuel based on the main fuel injection unit, and the control device controls the rotational speed of the engine during idling.

[0015] Effects of the Invention

[0016] According to the present invention, an engine device is provided that includes an engine capable of idling and low-load operation using a main fuel containing a low-GHG fuel having low greenhouse gas emissions while suppressing an increase in product cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram showing an engine device according to an embodiment of the present invention.

[0018] Figure 2 This is a schematic diagram showing an engine device according to another embodiment of the present invention.

[0019] Description of Reference Numerals

[0020] 1…Engine unit; 2…Multi-fuel engine; 3…Intake passage; 4…Exhaust passage; 5…Main fuel supply device; 6…Auxiliary fuel supply device; 7…Fuel injection unit; 7a…Main fuel injection unit; 7b…Auxiliary fuel injection unit; 8…Control unit; 11…Main fuel tank; 12…Main fuel pump; 13…Common rail; 14…Main fuel supply path; 15…Main fuel supply valve; 16…Auxiliary fuel tank; 17…Auxiliary fuel pump; 18…adjustment frame; 19…actuator; 20…auxiliary fuel supply path; 30…cylinder block; 31…cylinder; 31a…combustion chamber; 32…crankcase; 33…cylinder block; 34…piston; 35…cylinder head; 37…crankshaft; 38…connecting rod; 39…intake port; 40…exhaust port; 41…intake valve; 42…exhaust valve; 43…intake manifold; 43a…branch flow path; 44…exhaust manifold; 44a…branch flow path. DETAILED DESCRIPTION

[0021] An engine device 1 according to an embodiment of the present invention will be described with reference to the accompanying drawings. Figure 1 As shown, the engine device 1 includes a multi-fuel engine 2 , an intake passage 3 , an exhaust passage 4 , a main fuel supply device 5 , a sub-fuel supply device 6 , a fuel injection unit 7 , and a control device 8 .

[0022] In this embodiment, the multi-fuel engine 2 is configured to operate by burning at least one of a main fuel containing a low-GHG (Green House Gas) fuel such as ammonia or alcohol (e.g., ethanol, butanol, or methanol) that emits less greenhouse gases than petroleum-based fuels, and a hydrocarbon fuel (e.g., light oil, kerosene, or heavy oil) (i.e., auxiliary fuel) in the combustion chamber 31a of each cylinder 31 formed by a cylinder block 33 and a piston 34. The engine device 1 supplies a mixture of the main fuel and air to the combustion chamber 31a of each cylinder 31 of the multi-fuel engine 2. Furthermore, the supply of the main fuel and the auxiliary fuel is controlled by a control device 8.

[0023] The main fuel supply device 5 is composed of a common rail system including a main fuel tank 11, a main fuel pump 12, a common rail 13, a main fuel supply path 14 and a main fuel supply valve 15. When the multi-fuel engine 2 has a plurality of cylinders 31, Figure 1 The main fuel supply path 14 and the main fuel supply valve 15 for one cylinder 31 are shown in FIG. 1 , and the main fuel supply paths 14 and the main fuel supply valves 15 for the other cylinders 31 are omitted from illustration.

[0024] The main fuel tank 11 is filled with and stores a low-GHG fuel such as ammonia or alcohol that emits relatively little greenhouse gases, and is connected to a common rail 13 via a main fuel pump 12. The main fuel pump 12 pressurizes the main fuel stored in the main fuel tank 11 and supplies it to the common rail 13.

[0025] The common rail 13 is a main fuel pressure accumulator that accumulates the main fuel pressurized by the main fuel pump 12. It is provided commonly for the multiple cylinders 31 of the multi-fuel engine 2 and is connected to the fuel injectors 7 of each cylinder 31 via a main fuel supply path 14 provided for each cylinder 31. Each main fuel supply path 14 is provided with a main fuel supply valve 15 that opens and closes the supply of main fuel from the common rail 13 to the fuel injectors 7. The main fuel supply valve 15 is electrically controlled by the control device 8. When opened, the main fuel accumulated in the common rail 13 is supplied to the fuel injectors 7 via the main fuel supply path 14. In this manner, the main fuel supply device 5 is electrically controlled by the control device 8 to inject and supply the main fuel to the fuel injectors 7.

[0026] The auxiliary fuel supply device 6 is a mechanically controlled device including an auxiliary fuel tank 16, an auxiliary fuel pump 17, an adjustment frame 18, an actuator 19, and an auxiliary fuel supply path 20. When the multi-fuel engine 2 has a plurality of cylinders 31, Figure 1 The auxiliary fuel pump 17 and the auxiliary fuel supply path 20 for one cylinder 31 are shown in the figure, and the auxiliary fuel pumps 17 and the auxiliary fuel supply paths 20 for the other cylinders 31 are omitted from illustration.

[0027] The auxiliary fuel tank 16 is filled from the outside and stores an auxiliary fuel, namely, a hydrocarbon fuel such as light oil, kerosene, or heavy oil, and is connected to an auxiliary fuel pump 17 via an auxiliary fuel feed pump 16a. The auxiliary fuel pump 17 is an auxiliary fuel pressure accumulator provided for each cylinder 31 of the multi-fuel engine 2 and supplies the auxiliary fuel to the fuel injection unit 7. The auxiliary fuel pump 17 includes, for example, a cylindrical plunger sleeve 21, a cylindrical plunger 22, and an auxiliary fuel valve 23, and accumulates pressurized auxiliary fuel.

[0028] The plunger sleeve 21 is connected to the auxiliary fuel tank 16, and the auxiliary fuel is supplied from the auxiliary fuel tank 16 to the interior of the plunger sleeve 21 by the auxiliary fuel feed pump 16a. The plunger 22 is arranged in the interior of the plunger sleeve 21 and is slidable in the direction of penetration of the interior of the plunger sleeve 21.

[0029] In addition, the auxiliary fuel supply device 6 includes: a cam 24, which abuts against the plunger 22 at the other end side of the plunger sleeve 21 of each auxiliary fuel pump 17 in the penetration direction; a cam shaft 25, which supports the cam 24 of each auxiliary fuel pump 17 on the same axis; and a plunger spring 26, which urges the plunger 22 of each auxiliary fuel pump 17 toward the cam 24 side.

[0030] The cam 24 rotates together with the camshaft 25, and the plunger 22 in contact with the cam 24 reciprocates relative to the plunger sleeve 21. The plunger 22 moves toward the other end side in the penetration direction to introduce the auxiliary fuel, which is pressurized from the auxiliary fuel tank 16 by the auxiliary fuel feed pump 16a, into the interior space of the plunger sleeve 21. On the other hand, the plunger 22 moves toward the one end side in the penetration direction to pressurize the auxiliary fuel introduced into the interior space of the plunger sleeve 21.

[0031] The auxiliary fuel valve 23 is provided at one end of the plunger sleeve 21 in the direction of penetration and is connected to the auxiliary fuel supply passage 20. When the auxiliary fuel accumulated in the internal space of the plunger sleeve 21 reaches or exceeds a predetermined pressure threshold, the auxiliary fuel valve 23 opens, connecting the internal space of the plunger sleeve 21 with the auxiliary fuel supply passage 20, and supplying the auxiliary fuel from the auxiliary fuel pump 17 to the auxiliary fuel supply passage 20. For example, the auxiliary fuel valve 23 includes a biasing member. When the pressure applied to the auxiliary fuel valve 23 reaches or exceeds a predetermined pressure threshold, the auxiliary fuel valve 23 opens against the biasing force of the biasing member.

[0032] The adjustment frame 18 is provided commonly for the multiple cylinders 31 of the multi-fuel engine 2 and adjusts the amount of auxiliary fuel supplied by each auxiliary fuel pump 17. For example, the auxiliary fuel supply device 6 includes a pinion 27 that rotates integrally with the plunger 22 of each auxiliary fuel pump 17, and the adjustment frame 18 is configured to mesh with each pinion 27. By linearly moving the adjustment frame 18, the pinions 27 rotate simultaneously, thereby simultaneously rotating the plungers 22 of each auxiliary fuel pump 17. The auxiliary fuel supply device 6 employs a known mechanism that utilizes the rotation of the plungers 22, enabling the auxiliary fuel supply amount to be adjusted by the rotation of the plungers 22. In other words, the auxiliary fuel supply amount can be adjusted by utilizing the movement of the adjustment frame 18.

[0033] The actuator 19 drives the adjustment frame 18 to linearly move, and can be configured using, for example, a solenoid or a motor. The actuator 19 operates in response to an electrical signal from the control device 8 to drive the adjustment frame 18 .

[0034] In this manner, the auxiliary fuel supply device 6 operates in a mechanically controlled manner, injecting and supplying the auxiliary fuel pressurized by the auxiliary fuel pump 17 to the fuel injection portion 7 via the auxiliary fuel supply passage 20. Furthermore, the actuator 19 operates in response to an electrical signal from the control device 8. However, as with conventional mechanically controlled fuel supply devices, the auxiliary fuel supply amount is mechanically adjusted by the movement of the adjustment frame 18. In this specification, the configuration in which the fuel supply amount is adjusted using the adjustment frame 18 is referred to as a mechanically controlled (mechanical) configuration.

[0035] The fuel injection unit 7 supplies the main fuel and the auxiliary fuel separately to the combustion chamber 31a. The fuel injection unit 7 includes a main fuel injection unit 7a, which injects the main fuel into the combustion chamber 31a, and an auxiliary fuel injection unit 7b, which injects the auxiliary fuel into the combustion chamber 31a. The fuel injection unit 7 is composed of, for example, two integrated fuel injectors. The control device 8 controls the injection timing, injection amount, injection pressure, number of injections, etc. of the main fuel, as well as the injection amount of the auxiliary fuel.

[0036] The fuel injection unit 7 injects the main fuel into the combustion chamber 31a when the piston 34 approaches bottom dead center. Furthermore, when the mixture of the main fuel and air supplied to the combustion chamber 31a is compressed and heated and pressurized by the piston 34 approaching top dead center, the auxiliary fuel is injected into the mixture in the combustion chamber 31a, thereby igniting the mixture and causing combustion. In other words, the fuel injection unit 7 (auxiliary fuel injection unit 7b) functions as an ignition device that ignites the mixture in the combustion chamber 31a.

[0037] The two types of fuel injectors constituting the fuel injection unit 7 are configured, for example, to include a first valve chamber for supplying the main fuel to a single valve body and a second valve chamber for supplying the auxiliary fuel. The main fuel and auxiliary fuel can be supplied separately by opening and closing valve bodies provided in the respective valve chambers. Alternatively, the two types of fuel injectors are configured to include a first passage for supplying the main fuel and a second passage for supplying the auxiliary fuel to a single valve body, and to include injection holes communicating with each passage. The main fuel and auxiliary fuel can be supplied separately by switching the first and second passages with respect to the injection holes.

[0038] The multi-fuel engine 2 is, for example, a four-stroke engine, and is configured such that a cylinder block 30 includes a plurality of cylinders 31 and a crankcase 32 (see Figure 2 ).exist Figure 1 1 cylinder 31 is shown in FIG, and the illustration of the other cylinders 31 is omitted. Figure 1 As shown, each cylinder 31 is configured to include a cylinder block 33 , a piston 34 , and a cylinder head 35 .

[0039] The cylinder 33 is formed into a cylindrical shape, for example, within the cylinder block 30, and the piston 34 is slidably housed within the cylinder 33. A cylinder head 35 is mounted on the upper side of the cylinder 33, and a combustion chamber 31a is formed inside the cylinder 33 and the cylinder head 35. The fuel injection unit 7 for injecting the main fuel and the auxiliary fuel into the combustion chamber 31a is provided in the cylinder head 35.

[0040] Each cylinder block 33 of the plurality of cylinders 31 is connected to a crankcase 32, and a crankshaft 37 is rotatably supported by the crankcase 32. The piston 34 of each cylinder 31 is connected to the crankshaft 37 via a connecting rod 38, and the reciprocating motion of the piston 34 is converted into rotational motion of the crankshaft 37 via the connecting rod 38.

[0041] The cylinder head 35 has an intake port 39 and an exhaust port 40 communicating with the combustion chamber 31 a of the cylinder block 33 , and includes an intake valve 41 and an exhaust valve 42 for opening and closing the intake port 39 and the exhaust port 40 , respectively, with respect to the combustion chamber 31 a .

[0042] The intake port 39 is connected to the intake passage 3 and introduces air supplied from the intake passage 3 into the combustion chamber 31a. The exhaust port 40 is connected to the exhaust passage 4 and discharges exhaust gas generated in the combustion chamber 31a into the exhaust passage 4. By opening the intake valve 41, a mixture of main fuel and air can be drawn into the combustion chamber 31a through the intake port 39. On the other hand, by opening the exhaust valve 42, the exhaust gas generated in the combustion chamber 31a can be discharged through the exhaust port 40.

[0043] The intake passage 3 is connected to the multiple cylinders 31 of the multi-fuel engine 2, supplying compressed and cooled air to each cylinder 31. A mixture of air supplied from the intake passage 3 and a main fuel supplied from the main fuel supply device 5 is supplied from the intake passage 3 to the combustion chamber 31a of each cylinder 31. For example, the intake passage 3 is connected to the multi-fuel engine 2 via an intake manifold 43. The intake manifold 43 has branching flow paths 43a that branch toward the multiple cylinders 31, and each branch flow path 43a is connected to a respective intake port 39.

[0044] The exhaust passage 4 is connected to the multiple cylinders 31 of the multi-fuel engine 2, allowing exhaust gas generated in each cylinder 31 to flow and be discharged. For example, the exhaust passage 4 is connected to the multi-fuel engine 2 via an exhaust manifold 44. The exhaust manifold 44 has branching flow paths 44a that branch to the multiple cylinders 31, and each branch flow path 44a is connected to a respective exhaust port 40. Furthermore, the exhaust passage 4 may include a treatment device, such as a selective reduction catalyst or an ammonia adsorption catalyst, on the downstream side of the exhaust direction for treating the exhaust gas flowing through the exhaust passage 4.

[0045] The control device 8 is a computer such as an ECU (Engine Control Unit) that controls the operation of the multi-fuel engine 2. It includes a CPU, ROM, RAM, etc., and is configured to control various components of the multi-fuel engine 2. The control device 8 can store various programs for controlling the multi-fuel engine 2 and controls the multi-fuel engine 2 by reading and executing the programs.

[0046] In this embodiment, the control device 8 electrically controls at least one of the injection amount, injection pressure, injection timing, and number of injections of the main fuel from the main fuel injectors 7a of the fuel injection unit 7, and also controls the rotational speed of the multi-fuel engine 2 during idling or low-load operation. Specifically, when the control device 8 causes the multi-fuel engine 2 to operate at a relatively low rotational speed, the control device 8 controls at least one of the injection amount, injection pressure, injection timing, and number of injections of the main fuel to correspond to the low rotational speed of the multi-fuel engine 2, thereby performing a small injection of the main fuel. In this case, the control device 8 electrically controls each main fuel supply valve 15 corresponding to each cylinder 31, thereby controlling at least one of the injection amount, injection pressure, injection timing, and number of injections of the main fuel, so that the main fuel from the main fuel injectors 7a can be injected in a small amount.

[0047] For example, when the multi-fuel engine 2 is idling or operating at low load, and a small amount of main fuel is injected, the control device 8 controls the injection of the main fuel by the main fuel injection portion 7a (injection amount, injection pressure, injection timing, number of injections, etc.) so that the calorific value of the main fuel relative to the total calorific value of the main fuel and the auxiliary fuel is 50% or more. Furthermore, the control device 8 may control the injection of the main fuel so that the calorific value of the main fuel relative to the total calorific value of the main fuel and the auxiliary fuel is 50% or more during a predetermined period of idling or operating at low load.

[0048] Furthermore, for example, when a small amount of main fuel is injected during idling or low-load operation of the multi-fuel engine 2, the control device 8 controls the injection of the main fuel by the main fuel injector 7a (injection amount, injection pressure, injection timing, number of injections, etc.) so that the injection pressure of the main fuel by the main fuel injector 7a is higher than the injection pressure of the auxiliary fuel by the auxiliary fuel injector 7b. In this case, the control device 8 can control so that the maximum injection pressure of the main fuel is higher than the maximum injection pressure of the auxiliary fuel during one cycle of the multi-fuel engine 2.

[0049] Furthermore, for example, during idling or low-load operation of the multi-fuel engine 2, the control device 8 controls the injection of the main fuel by the main fuel injection portion 7a so that the main fuel is injected multiple times into each cylinder 31 during one cycle of the multi-fuel engine 2. In this case, the control device 8 may control the injection of the main fuel multiple times during the compression stroke of each cylinder 31, and may perform the control when the piston 34 is approaching top dead center, when the piston 34 reaches top dead center, or immediately after the piston 34 reaches top dead center.

[0050] Furthermore, the control device 8 can control the amount of auxiliary fuel injected by the auxiliary fuel injection unit 7b. For example, the control device 8 controls the amount of auxiliary fuel injected by the auxiliary fuel injection unit 7b by sending an electrical signal to the actuator 19 of the auxiliary fuel supply device 6 and controlling the movement of the adjustment frame 18.

[0051] As described above, according to the present invention, an engine device 1 that operates by burning a main fuel containing a low-GHG fuel that emits fewer greenhouse gases than petroleum-based fuels and a hydrocarbon-based auxiliary fuel includes: a main fuel injection portion 7a of a fuel injection portion 7 that electrically controls the injection of the main fuel; an auxiliary fuel injection portion 7b of the fuel injection portion 7 that mechanically controls the injection of the auxiliary fuel; and a control device 8 that electrically controls at least one of the injection amount, injection pressure, injection timing, and number of injections of the main fuel by the main fuel injection portion 7a. The control device 8 controls the rotational speed of the multi-fuel engine 2 during idling. For example, the main fuel contains ammonia or alcohol as the low-GHG fuel.

[0052] Thus, according to the engine device 1 of the present invention, a common rail system is used as the injection unit for the main fuel, and a mechanically controlled device is used as the injection unit for the auxiliary fuel, thereby suppressing cost increases. In addition, by using the common rail system to inject a flame-retardant main fuel such as ammonia or alcohol, it is possible to achieve micro-injection, high-pressure injection, and injection at the optimal injection time. Therefore, stable idling and low-load operation using the main fuel can be achieved, and the idle speed can also be reduced. In addition, during idling and low-load operation, the use of main fuels such as ammonia or alcohol, which are low-GHG fuels, is not restricted, which can promote the reduction of greenhouse gas emissions.

[0053] In the engine device 1 of the present invention, the control device 8 controls the injection of the main fuel so that the calorific value of the main fuel becomes 50% or more of the total calorific value of the main fuel and the auxiliary fuel during idling of the multi-fuel engine 2.

[0054] As a result, the engine device 1 can use more main fuel during idling, thereby suppressing consumption of hydrocarbon auxiliary fuel and increasing consumption of main fuel, which is a low-GHG fuel, thereby contributing to protection of the global environment.

[0055] Furthermore, in the engine device 1 of the present invention, the control device 8 performs control so that the injection pressure of the main fuel becomes higher than the injection pressure of the auxiliary fuel.

[0056] Thus, the engine device 1 can inject the flame-retardant main fuel at a higher pressure than the auxiliary fuel using the common rail system to further atomize and enhance permeation, thereby improving the flame-retardancy of the main fuel.

[0057] Furthermore, in the engine device 1 of the present invention, the control device 8 controls the injection of the main fuel so that the injection of the main fuel into each cylinder 31 is performed a plurality of times in one cycle of the multi-fuel engine 2 .

[0058] Thus, the engine device 1 can improve exhaust gas properties and fuel efficiency by injecting and burning the main fuel multiple times.

[0059] Furthermore, in the engine system 1 of the present invention, the control device 8 controls the injection amount of the auxiliary fuel. For example, the engine system 1 of the present invention includes: an auxiliary fuel pump 17 that supplies the auxiliary fuel to the auxiliary fuel injection portion 7b; an adjustment rack 18 that adjusts the supply amount of the auxiliary fuel by the auxiliary fuel pump 17; and an actuator 19 that drives the adjustment rack 18. The actuator 19 operates in response to an electrical signal from the control device 8.

[0060] As a result, the engine system 1 can control the injection amount of the auxiliary fuel under the control of the common rail system control device 8, eliminating the need for a mechanically controlled device control device. Furthermore, it can avoid the dual control of injection control of multiple fuels. In particular, with respect to the mechanically controlled device serving as the auxiliary fuel injection unit, while determining the injection amount of the auxiliary fuel based on the operation of the regulating rack 18 with respect to the auxiliary fuel pump 17, the common rail system control device 8 controls the actuator 19 that drives the regulating rack 18, thereby enabling the auxiliary fuel injection amount to be controlled under the control of the common rail system control device 8.

[0061] In addition, in the above embodiment, the fuel injection unit 7 is described as comprising two types of fuel injectors, namely, the main fuel injection unit 7a for injecting the main fuel and the auxiliary fuel injection unit 7b for injecting the auxiliary fuel, but the present invention is not limited to this example. For example, in other embodiments, Figure 2 As shown, the fuel injection unit 7 may be composed of separate injectors, each comprising a main fuel injection unit 7a for injecting the main fuel and a secondary fuel injection unit 7b for injecting the secondary fuel. In this case, the main fuel injection unit 7a for injecting the main fuel may be configured to directly supply the main fuel to the combustion chamber 31a by injecting the main fuel directly into the combustion chamber 31a, or may be configured to indirectly supply the main fuel to the combustion chamber 31a by injecting the main fuel into the intake passage 3, the branch flow passage 43a, or the intake port 39.

[0062] Furthermore, the present invention may be modified as appropriate within the scope not departing from the gist or concept of the invention as reflected in the claims and the entire specification, and engine devices with such modifications are also encompassed within the technical concept of the present invention.

[0063] [Supplementary Notes on the Invention]

[0064] The following is a supplementary note on the outline of the invention extracted from the above embodiments. In addition, the various structures and processing functions described in the following supplementary notes can be selected and combined arbitrarily.

[0065] Note 1

[0066] An engine device is operated by burning a main fuel containing a low-GHG fuel having a lower greenhouse gas emission than petroleum-based fuel and a hydrocarbon-based auxiliary fuel, characterized in that:

[0067] The engine device comprises:

[0068] a main fuel injection portion that injects the main fuel by electric control;

[0069] a sub-fuel injection portion that injects the sub-fuel by mechanical control; and

[0070] a control device that electrically controls at least one of the injection amount, injection pressure, injection timing, and number of injections of the main fuel by the main fuel injection portion;

[0071] The control device controls the rotation speed of the engine during idling.

[0072] Note 2

[0073] The engine device according to Supplementary Note 1 is characterized in that:

[0074] The control device controls injection of the main fuel so that the calorific value of the main fuel becomes 50% or more with respect to the total calorific value of the main fuel and the auxiliary fuel during idling of the engine.

[0075] Note 3

[0076] The engine device according to Supplement 1 or 2 is characterized in that:

[0077] The control device controls injection of the main fuel so that an injection pressure of the main fuel becomes higher than an injection pressure of the sub-fuel.

[0078] Note 4

[0079] The engine device according to any one of Supplementary Notes 1 to 3, characterized in that:

[0080] The control device performs control so that the injection of the main fuel into each cylinder is performed a plurality of times in one cycle of the engine.

[0081] Note 5

[0082] The engine device according to any one of Supplementary Notes 1 to 4, characterized in that:

[0083] The control device controls the injection amount of the auxiliary fuel.

[0084] <Note 6>

[0085] The engine device according to Supplementary Note 5 is characterized in that:

[0086] The engine device comprises:

[0087] a sub-fuel pump that supplies the sub-fuel to the sub-fuel injection portion;

[0088] an adjustment frame for adjusting the supply amount of the auxiliary fuel by the auxiliary fuel pump; and an actuator for driving the adjustment frame.

[0089] The actuator performs an action according to an electrical signal from the control device.

[0090] <Note 7>

[0091] The engine device according to any one of Supplementary Notes 1 to 6, wherein the main fuel contains ammonia or alcohol as the low-GHG fuel.

Claims

1. An engine device that operates by burning a main fuel containing a low-GHG fuel that emits less greenhouse gases than petroleum-based fuels and a secondary fuel of a hydrocarbon type. It is characterized in that The engine device comprises: a main fuel injection portion that injects the main fuel by electric power control; a sub-fuel injection portion that injects the sub-fuel by mechanical control; and a control device that electrically controls at least one of the injection amount, injection pressure, injection timing, and number of injections of the main fuel by the main fuel injection portion; The control device controls the rotation speed of the engine during idling.

2. The engine device according to claim 1, characterized in that The control device controls injection of the main fuel so that the calorific value of the main fuel becomes 50% or more with respect to the total calorific value of the main fuel and the auxiliary fuel during idling of the engine.

3. The engine device according to claim 1, characterized in that The control device performs control so that the injection pressure of the main fuel becomes higher than the injection pressure of the sub-fuel.

4. The engine device according to claim 1, characterized in that The control device performs control so that the injection of the main fuel into each cylinder is performed a plurality of times in one cycle of the engine.

5. The engine device according to claim 1, characterized in that The control device controls the injection amount of the auxiliary fuel.

6. The engine device according to claim 5, characterized in that The engine device comprises: a sub-fuel pump that supplies the sub-fuel to the sub-fuel injection portion; an adjustment rack that adjusts a supply amount of the auxiliary fuel by the auxiliary fuel pump; as well as an actuator for driving the adjustment mount, The actuator performs an action according to an electrical signal from the control device.

7. The engine device according to claim 1, characterized in that The main fuel contains ammonia or alcohol as the low GHG fuel.

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