Engine device

Abstract

The present invention provides an engine device capable of stably combusting a main fuel, which is a low GHG fuel having a small amount of global warming gas emission, using a single fuel injection valve for injecting two types of fuels independently from each other. An engine device (1) is provided with: an engine (2) that operates by combusting two types of fuel; and one fuel injection valve (7) capable of individually injecting two types of fuel to the engine (2). In the engine device (1), when a control device (8) uses a fuel injection valve (7) to inject a main fuel containing a low GHG fuel having a lower global warming gas emission than a petroleum fuel and a hydrocarbon sub-fuel into an engine (2) as two types of fuels, before 50% of the total injection amount of the main fuel is injected into one cycle of the engine (2), the fuel injection valve (7) injects the main fuel into the engine (2), and the fuel injection valve (7) injects the hydrocarbon sub-fuel into the engine (2) before 50% of the total injection amount of the main fuel into the engine (2). 90% of the total injection amount of the auxiliary fuel is injected.

Description

Technical Field

[0001] The present invention relates to an engine device including: an engine that operates by burning two types of fuel; and a fuel injection valve that can independently inject the two types of fuel into the engine. Background Art

[0002] Conventionally, some engine devices include an engine that operates by burning two types of fuel, and it is necessary to supply the two types of fuel separately to the engine. Therefore, the engine device includes a single fuel injection valve that can inject the two types of fuel separately to the engine.

[0003] For example, Patent Document 1 discloses a fuel injection device for an internal combustion engine that injects a first fuel and a second fuel, each different from the first fuel, into a cylinder from a common fuel injection valve. The fuel injection valve has a first valve chamber disposed at its center and a second valve chamber disposed on its periphery, separated from the first valve chamber by a partition wall. The fuel injection valve comprises a valve body at its distal end, having a first injection hole communicating with the first valve chamber and a second injection hole communicating with the second valve chamber; a first valve element disposed in the first valve chamber to open and close the first injection hole; a second valve element disposed in the second valve chamber to open and close the second injection hole; a first drive mechanism to open and close the first valve element; and a second drive mechanism to open and close the second valve element independently of the first drive mechanism's drive of the first valve element, thereby directing the first fuel to either the first or second valve chamber and directing the other fuel to the other valve chamber.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2009-057884 Summary of the Invention

[0007] In the prior art disclosed in Patent Document 1, the fuel injection device essentially incorporates two common rail systems, which are used to independently inject two types of fuel from a single fuel injection valve. However, compared to other technologies that independently inject two types of fuel from two fuel injection valves using two common rail systems, this prior art is structurally complex and sophisticated, resulting in increased commercial costs and manufacturing difficulties.

[0008] Furthermore, Patent Document 1 provides only limited disclosure regarding the control and usage methods for injecting two fuels. However, based on the prior art described above, there is no disclosure or suggestion regarding the effective use of two fuels when injecting a primary fuel (a low-GHG (Green House Gas) fuel with low greenhouse gas emissions, such as ammonia or alcohol) and a secondary fuel (a hydrocarbon fuel, such as light oil). Consequently, there are challenges in improving the combustion instability of the flame-retardant primary fuel or promoting the reduction of greenhouse gas emissions.

[0009] An object of the present invention is to provide an engine device capable of stably burning a main fuel that is a low-GHG fuel having low greenhouse gas emissions, using a single fuel injection valve that injects two fuels independently of each other.

[0010] In order to solve the above-mentioned problems, the engine device of the present invention comprises: an engine that operates by burning two types of fuels; and a fuel injection valve that can separately inject the two types of fuels into the engine, and is characterized in that, when a main fuel containing a low-GHG fuel that emits less greenhouse gases than petroleum fuels and a hydrocarbon-based auxiliary fuel are injected into the engine using the fuel injection valve, in one cycle of the engine, 90% of the total injection amount of the auxiliary fuel is injected before 50% of the total injection amount of the main fuel is injected.

[0011] Effects of the Invention

[0012] According to the present invention, an engine device is provided that can stably burn a main fuel that is a low-GHG fuel having low greenhouse gas emissions, using a single fuel injection valve that injects two fuels independently of each other. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram showing an example of an engine device according to an embodiment of the present invention.

[0014] Figure 2 Schematic diagram showing an example of a fuel injection valve of an engine device according to an embodiment of the present invention.

[0015] Figure 3 This is a graph showing an example of the injection timing of the main fuel and the auxiliary fuel in the engine device according to the embodiment of the present invention.

[0016] Figure 4 This is a graph showing an example of the injection timing of the main fuel and the auxiliary fuel in the engine device according to the first modified example of the present invention.

[0017] Figure 5This is a graph showing an example of the injection timing of the main fuel and the auxiliary fuel in the engine device according to the second modified example of the present invention.

[0018] Figure 6 This is a graph showing an example of the injection timing of the main fuel and the auxiliary fuel in the engine device according to the third modified example of the present invention.

[0019] Figure 7 This is a graph showing an example of the injection timing of the main fuel and the auxiliary fuel in the engine device according to the fourth modified example of the present invention.

[0020] Figure 8 This is a graph showing an example of the injection timing of the main fuel and the auxiliary fuel in the engine device according to the fifth modified example of the present invention.

[0021] Description of Reference Numerals

[0022] 1…Engine unit; 2…Engine; 3…Intake passage; 4…Exhaust passage; 5…Main fuel supply device; 6…Auxiliary fuel supply device; 7…Fuel injection valve; 7a…Main fuel injection unit; 7b…Auxiliary fuel injection unit; 8…Control unit; 11…Main fuel container; 12…Main fuel supply unit; 14…Auxiliary fuel container; 15…Auxiliary fuel supply unit; 20…Valve body; 21…First valve chamber; 22…Second valve chamber; 23…First injection hole; 24…Second injection hole ; 25…first valve body; 26…second valve body; 27…first drive unit; 28…second drive unit; 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

[0023] 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 an engine 2 , an intake passage 3 , an exhaust passage 4 , a main fuel supply device 5 , a sub-fuel supply device 6 , fuel injection valves 7 , and a control device 8 .

[0024] In this embodiment, the 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 (i.e., auxiliary fuel) such as light oil, kerosene, or heavy oil, in the combustion chamber 31a of each cylinder 31 formed by the cylinder block 33 and piston 34. The engine device 1 supplies the main fuel, auxiliary fuel, and air to the combustion chamber 31a of each cylinder 31 of the engine 2, generating a mixture of the main fuel and air, a mixture of the auxiliary fuel and air, or a mixture of the main fuel, auxiliary fuel, and air in the combustion chamber 31a. Furthermore, the supply of the main fuel and the auxiliary fuel is controlled by the control device 8 of the engine device 1.

[0025] The main fuel supply device 5 includes a main fuel tank 11 and a main fuel supply portion 12 .

[0026] The main fuel tank 11 is filled from the outside with a main fuel such as ammonia or alcohol, which emits relatively little greenhouse gas, and stores the main fuel. The main fuel tank 11 is connected to the fuel injection valve 7 via a main fuel supply unit 12 .

[0027] The main fuel supply unit 12 pressurizes the main fuel supplied from the main fuel tank 11 and supplies it to the fuel injection valve 7. The main fuel supply unit 12 may pressurize and supply the main fuel using a common rail system or a mechanically controlled device.

[0028] The auxiliary fuel supply device 6 includes an auxiliary fuel tank 14 and an auxiliary fuel supply portion 15 .

[0029] The auxiliary fuel tank 14 is filled from the outside and stores an auxiliary fuel such as a hydrocarbon fuel such as light oil, kerosene, or heavy oil, and is connected to an auxiliary fuel supply unit 15 .

[0030] The auxiliary fuel supply unit 15 pressurizes the auxiliary fuel supplied from the auxiliary fuel tank 14 and supplies it to the fuel injection valve 7. The auxiliary fuel supply unit 15 may pressurize and supply the auxiliary fuel using a common rail system or a mechanically controlled device.

[0031] A fuel injection valve 7 is provided for each cylinder 31 of the engine 2, and supplies a main fuel and a secondary fuel to the combustion chamber 31a of each cylinder 31. The fuel injection valve 7 is composed of, for example, two integrated fuel injectors, comprising a main fuel injection portion 7a that injects the main fuel into the combustion chamber 31a, and a secondary fuel injection portion 7b that injects the secondary fuel into the combustion chamber 31a. The fuel injection valve 7 is provided in the cylinder head 35 so as to inject the main fuel and the secondary fuel from near the radial center of each combustion chamber 31a (cylinder body 33). The fuel injection valve 7 is controlled by a control device 8 in terms of the injection timing, injection amount, injection pressure, and number of injections of the main and secondary fuels.

[0032] For example Figure 2 As shown, the fuel injection valve 7, which serves as two types of fuel injectors, includes a cylindrical first valve chamber 21 for supplying a main fuel to a cylindrical valve body 20, and a cylindrical second valve chamber 22 for supplying an auxiliary fuel. Each valve chamber 21 is provided with a first injection hole 23 connecting the first valve chamber 21 to the outside, and a second injection hole 24 connecting the second valve chamber 22 to the outside. The fuel injection valve 7 includes a cylindrical first valve body 25 that slides within the first valve chamber 21, and a cylindrical second valve body 26 that slides within the second valve chamber 22. Each valve chamber 22 includes a first drive unit 27 for driving the first valve body 25, and a second drive unit 28 for driving the second valve body 26.

[0033] The main fuel injection unit 7a is configured to include a first valve chamber 21, a first injection hole 23, a first valve body 25, and a first drive unit 27. Furthermore, the auxiliary fuel injection unit 7b is configured to include a second valve chamber 22, a second injection hole 24, a second valve body 26, and a second drive unit 28. The auxiliary fuel injection unit 7b functions as an ignition device that injects auxiliary fuel into a mixture of main fuel and air or compressed air compressed in the combustion chamber 31a to ignite the mixture.

[0034] The first drive unit 27 drives the first valve body 25 in response to an electrical signal from the control device 8, causing the first valve body 25 to slide within the first valve chamber 21 between a closed position for closing the first injection hole 23 and an open position for opening the first injection hole 23. The second drive unit 28 drives the second valve body 26 in response to an electrical signal from the control device 8, causing the second valve body 26 to slide within the second valve chamber 22 between a closed position for closing the second injection hole 24 and an open position for opening the second injection hole 24.

[0035] The first valve chamber 21 is connected to the main fuel supply section 12, and pressurized main fuel is supplied from the main fuel supply section 12 to the first valve chamber 21. The first valve body 25 opens the first injection hole 23, thereby injecting the main fuel from the first valve chamber 21 through the first injection hole 23 to the outside of the fuel injection valve 7. The second valve chamber 22 is connected to the auxiliary fuel supply section 15, and pressurized auxiliary fuel is supplied from the auxiliary fuel supply section 15 to the second valve chamber 22. The second valve body 26 opens the second injection hole 24, thereby injecting the auxiliary fuel from the second valve chamber 22 through the second injection hole 24 to the outside of the fuel injection valve 7.

[0036] The fuel injection valve 7 usually injects main fuel into the combustion chamber 31a when the piston 34 is toward the top dead center. In addition, when the mixture of the main fuel and air supplied to the combustion chamber 31a is compressed and heated / pressurized by the piston 34 toward the top dead center, the auxiliary fuel is injected into the mixture in the combustion chamber 31a, thereby igniting the mixture and causing it to burn.

[0037] The engine 2 is, for example, a 4-stroke engine, and is configured such that a cylinder block 30 includes a plurality of cylinders 31 and a crankcase 32. Figure 1 In FIG, one cylinder 31 is shown, and the other cylinders 31 are omitted. Figure 1 As shown, each cylinder 31 is composed of a cylinder block 33 , a piston 34 and a cylinder head 35 .

[0038] 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 combustion chambers 31a are formed inside the cylinder 33 and the cylinder head 35. Fuel injection valves 7 for injecting main fuel and auxiliary fuel into each combustion chamber 31a are provided in the cylinder head 35 so as to inject fuel from the radial center of each combustion chamber 31a (cylinder 33).

[0039] 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.

[0040] 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 .

[0041] The intake port 39 is connected to the intake passage 3 to introduce air supplied from the intake passage 3 into the combustion chamber 31a, and the exhaust port 40 is connected to the exhaust passage 4 to discharge exhaust gas generated in the combustion chamber 31a into the exhaust passage 4. By opening the intake valve 41, air from the intake passage 3 can be drawn into the combustion chamber 31a via the intake port 39, while by opening the exhaust valve 42, exhaust gas generated in the combustion chamber 31a can be discharged via the exhaust port 40.

[0042] The intake passage 3 is connected to the multiple cylinders 31 of the engine 2, supplying compressed and cooled air to each cylinder 31. Air is supplied from the intake passage 3 to the combustion chamber 31a of each cylinder 31, and a main fuel is supplied from the main fuel supply device 5 to the combustion chamber 31a of each cylinder 31, thereby generating a mixed gas composed of the main fuel and air in the combustion chamber 31a of each cylinder 31. Alternatively, a secondary fuel is supplied from the secondary fuel supply device 6 to the combustion chamber 31a of each cylinder 31, thereby generating a mixed gas composed of the secondary fuel and air in the combustion chamber 31a of each cylinder 31. The intake passage 3 is connected to the engine 2 via, for example, 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.

[0043] The exhaust passage 4 is connected to the plurality of cylinders 31 of the engine 2, allowing exhaust gas generated in each cylinder 31 to flow through and be discharged. The exhaust passage 4 is connected to the engine 2 via, for example, an exhaust manifold 44. The exhaust manifold 44 has branching flow paths 44a that branch toward the plurality of 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.

[0044] The control device 8 is a computer such as an ECU (Engine Control Unit) that controls the operation of the engine 2. It includes a CPU, ROM, RAM, etc., and is configured to control various components of the engine 2. The control device 8 can store various programs for controlling the engine 2, read out the programs, and execute them to control the engine 2.

[0045] In this embodiment, the control device 8 uses electricity to control the injection amount, injection pressure, injection timing, and number of injections of the main fuel by the main fuel injector 7a of the fuel injection valve 7, and also uses electricity to control the injection amount, injection pressure, injection timing, and number of injections of the auxiliary fuel by the auxiliary fuel injector 7b. In this case, the control device 8 controls the injection amount and / or injection timing of the main fuel and the auxiliary fuel so that 90% of the total injection amount of the auxiliary fuel is injected before 50% of the total injection amount of the main fuel, when injecting a predetermined total injection amount of the main fuel and a predetermined total injection amount of the auxiliary fuel into the combustion chamber 31a of the engine 2 during each cycle of the engine 2. Furthermore, the total injection amount of the main fuel can be determined by weight, volume, calorific value, or the like, and the total injection amount of the auxiliary fuel can be determined by weight, volume, calorific value, or the like.

[0046] For example Figure 3 As shown, when the piston 34 reaches the top dead center during the compression stroke of each cylinder 31, the control device 8 controls the fuel injection valve 7 so that 90% of the total injection amount of the auxiliary fuel is injected before 50% of the total injection amount of the main fuel is injected. Figure 3 In the example shown, the auxiliary fuel is started before the main fuel is started. The main fuel is injected into the combustion chamber 31a while the auxiliary fuel is compressed and ignited and burned in the combustion chamber 31a, thereby facilitating the combustion of the difficult-to-combust main fuel.

[0047] In addition, in the above embodiment, if Figure 3 The figure shows an example in which the fuel injection valve 7 injects the main fuel around the time when the piston 34 reaches top dead center. However, the present invention only requires that 90% of the total injection amount of the auxiliary fuel be injected before 50% of the total injection amount of the main fuel is injected, and the timing of main fuel injection is not limited to this example. Alternatively, in other examples, the fuel injection valve 7 may complete injection of the total injection amount of the main fuel before the piston 34 reaches top dead center, or may begin injection of the main fuel after the piston 34 reaches top dead center.

[0048] In addition, in the above embodiment, if Figure 3 The figure shows an example in which the fuel injection valve 7 injects the auxiliary fuel around the time when the piston 34 reaches top dead center. However, the present invention only requires that 90% of the total injection amount of the auxiliary fuel be injected before 50% of the total injection amount of the main fuel is injected, and the timing of auxiliary fuel injection is not limited to this example. Alternatively, in other examples, the fuel injection valve 7 may complete injection of the total injection amount of the auxiliary fuel before the piston 34 reaches top dead center, or may begin injection of the auxiliary fuel after the piston 34 reaches top dead center.

[0049] As described above, according to the present invention, an engine device 1 includes an engine 2 that operates by combusting two fuels, and a fuel injection valve 7 capable of independently injecting each of the two fuels into the engine 2. In this engine device 1, when a control device 8 injects a main fuel containing a low-GHG fuel that emits fewer greenhouse gases than petroleum-based fuels and a hydrocarbon-based auxiliary fuel into the engine 2 via the fuel injection valve 7, 90% of the total auxiliary fuel injection amount is injected before 50% of the total main fuel injection amount is injected during one cycle of the engine 2. For example, the main fuel contains ammonia or alcohol as the low-GHG fuel.

[0050] Thus, according to the engine device 1 of the present invention, by independently injecting the main fuel and the auxiliary fuel from a single fuel injection valve 7, the main fuel and the auxiliary fuel can be injected from the radial center of the cylinder 33 (combustion chamber 31a). Furthermore, during a single cycle of the engine 2, a large amount of the auxiliary fuel is injected in the first half of the main fuel injection, thereby promoting combustion in the first half of combustion, with the highly flammable auxiliary fuel as the primary fuel. Subsequently, the heat and flame generated by the combustion of the auxiliary fuel promote the combustion of the less flammable main fuel, thereby achieving stable combustion. Thus, according to the engine device 1, by utilizing a single fuel injection valve 7 that independently injects two fuels, it is possible to stably combust the main fuel, which is a low-GHG fuel with low greenhouse gas emissions.

[0051] And, as a first modification, Figure 4 As shown, the control device 8 controls the fuel injection valve 7 in such a manner that, while a mixture of main fuel and air is generated in each combustion chamber 31a of the engine 2 by injection of the main fuel, the auxiliary fuel is injected from the radial center of the combustion chamber 31a, and 90% of the total injection amount of the auxiliary fuel is injected before 50% of the total injection amount of the main fuel is injected. For example, Figure 4 In the example shown, the injection of the main fuel is started to generate a mixed gas of the main fuel and air in each combustion chamber 31a and compress it, then the injection of the auxiliary fuel is started and the mixed gas of the main fuel is ignited in each combustion chamber 31a, and then the main fuel is injected into each combustion chamber 31a and burned.

[0052] Thus, while the main fuel mixture is generated in the combustion chamber 31a, the auxiliary fuel is injected from the radial center of the combustion chamber 31a, thereby igniting the main fuel mixture with the auxiliary fuel and propagating the flame to the main fuel mixture, thereby achieving stable combustion.

[0053] Or, as a second variation, Figure 5As shown, the control device 8 controls the fuel injection valve 7 in such a manner that, while a mixed gas of auxiliary fuel and air is generated in each combustion chamber 31a of the engine 2 by injection of auxiliary fuel, the main fuel is injected from the radial center of the combustion chamber 31a, and 90% of the total injection amount of the auxiliary fuel is injected before 50% of the total injection amount of the main fuel is injected. For example, Figure 5 In the example shown, injection of the auxiliary fuel is started to generate a mixture of the auxiliary fuel and air in each combustion chamber 31a. Then, when the mixture of the auxiliary fuel is compressed and ignited, injection of the main fuel is started and the main fuel is burned in each combustion chamber 31a.

[0054] Thus, while a mixture of auxiliary fuel and main fuel is generated in the combustion chamber 31a, the main fuel is injected from the radial center of the combustion chamber 31a, thereby igniting the auxiliary fuel and starting combustion mainly based on the auxiliary fuel. Then, the combustion of the auxiliary fuel causes the flame to propagate to the main fuel, thereby achieving stable combustion.

[0055] In addition, as a third modification example, Figure 6 As shown, the control device 8 controls the fuel injection valve 7 in such a manner that, while the auxiliary fuel is ignited in each combustion chamber 31a of the engine 2 by injection of the auxiliary fuel, the main fuel is injected from the radial center of the combustion chamber 31a, and the injection of 90% of the total injection amount of the auxiliary fuel is completed before 50% of the total injection amount of the main fuel is injected. For example, Figure 6 In the example shown, injection of the auxiliary fuel is started, and a mixture of the auxiliary fuel and air generated in each combustion chamber 31 a is compressed and ignited. Then, injection of the main fuel is started, and the main fuel is combusted in each combustion chamber 31 a.

[0056] Thus, while the auxiliary fuel is ignited to generate flames in the combustion chamber 31a, the main fuel is injected from the radial center of the combustion chamber 31a. The combustion of the auxiliary fuel propagates the flames to the main fuel, thereby achieving stable combustion.

[0057] In addition, the fuel injection valve 7 may be as in the second modified example (see Figure 5 ) after the injection of the auxiliary fuel (injection of 100% of the total injection amount) is completed, or the injection of the main fuel may be started as in the third modification (refer to Figure 6 ) as in the case where the injection of the main fuel is started after the injection of 90% of the total injection amount of the sub-fuel is completed and before the injection of 100% of the total injection amount of the sub-fuel is completed.

[0058] In addition, as a fourth modification example, Figure 7As shown, the control device 8 controls the fuel injection valve 7 in the following manner: in one cycle of the engine 2, the main fuel is injected multiple times, and before 50% of the total injection amount of the main fuel is injected, 90% of the total injection amount of the auxiliary fuel is injected. Figure 7 In the example shown, the main fuel is injected twice, half the total injection amount. The first injection of the main fuel and the injection of the auxiliary fuel are initiated to generate a mixture of the main fuel, the auxiliary fuel, and air in each combustion chamber 31a. The auxiliary fuel mixture is compressed and ignited, and the main fuel mixture is combusted. Finally, the second injection of the main fuel is initiated and combusted in each combustion chamber 31a. In the fourth modified example, the number of main fuel injections is not limited to two, and may be three or more.

[0059] Thus, the main fuel injection is divided into multiple times, thereby controlling the combustion rate of the main fuel, suppressing a sudden increase in pressure and temperature and the resulting combustion noise, and achieving improved exhaust gas properties and reduced fuel consumption.

[0060] In addition, as a fifth modification, Figure 8 As shown, the control device 8 controls the fuel injection valve 7 in the following manner: in one cycle of the engine 2, the auxiliary fuel is injected multiple times, and before 50% of the total injection amount of the main fuel is injected, 90% of the total injection amount of the auxiliary fuel is injected. Figure 8 In the illustrated example, the auxiliary fuel is injected twice, half the total injection amount. The first and second injections of the auxiliary fuel are initiated to generate a mixture of the auxiliary fuel and air in each combustion chamber 31a. Once the auxiliary fuel mixture is compressed and ignited, the main fuel is injected and combusted in each combustion chamber 31a. In the fifth modified example, the number of auxiliary fuel injections is not limited to two, and may be three or more.

[0061] By thus performing injection of the auxiliary fuel in multiple steps, the combustion timing of the main fuel can be controlled, a sudden increase in pressure and temperature and the resulting combustion noise can be suppressed, and exhaust gas properties and fuel efficiency can be improved.

[0062] Furthermore, in the above embodiment, the fuel injection valve 7 is described as including a main fuel injection portion 7a having a first valve chamber 21, a first nozzle hole 23, a first valve body 25, and a first drive portion 27; and a secondary fuel injection portion 7b having a second valve chamber 22, a second nozzle hole 24, a second valve body 26, and a second drive portion 28. However, the present invention is not limited to this example. Alternatively, in another example, the fuel injection valve 7 may include a first passage for supplying the main fuel and a second passage for supplying the secondary fuel to a single valve body, and a nozzle hole communicating with each passage. The first and second passages may be switched with respect to the nozzle hole to enable separate supply of the main fuel and the secondary fuel.

[0063] 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.

[0064] [Supplementary Notes on the Invention]

[0065] 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.

[0066] Note 1

[0067] An engine device includes: an engine that operates by burning two types of fuel; and a fuel injection valve that can independently inject the two types of fuel into the engine.

[0068] It is characterized by:

[0069] When a main fuel containing a low-GHG fuel having lower greenhouse gas emissions than petroleum-based fuels and a hydrocarbon-based auxiliary fuel are injected into the engine using the fuel injection valve as the two fuels, 90% of the total injection amount of the auxiliary fuel is injected before 50% of the total injection amount of the main fuel is injected in one cycle of the engine.

[0070] Note 2

[0071] The engine device according to Supplementary Note 1 is characterized in that:

[0072] The auxiliary fuel is injected from the radial center of the combustion chamber in a state where a mixed gas of the main fuel and air is generated in the combustion chamber of the engine by injection of the main fuel.

[0073] Note 3

[0074] The engine device according to Supplementary Note 1 is characterized in that:

[0075] The main fuel is injected from the radial center of the combustion chamber in a state where a mixed gas of the auxiliary fuel and air is generated in the combustion chamber of the engine by injection of the auxiliary fuel.

[0076] Note 4

[0077] The engine device according to Supplementary Note 3 is characterized in that:

[0078] The main fuel is injected from a radial center of the combustion chamber in a state where the auxiliary fuel is ignited in the combustion chamber of the engine by injection of the auxiliary fuel.

[0079] Note 5

[0080] The engine device according to any one of Supplementary Notes 1 to 4, characterized in that:

[0081] The main fuel is injected multiple times in one cycle of the engine.

[0082] <Note 6>

[0083] The engine device according to any one of Supplementary Notes 1 to 5, characterized in that:

[0084] The auxiliary fuel is injected multiple times in one cycle of the engine.

[0085] <Note 7>

[0086] The engine device according to any one of Supplementary Notes 1 to 6, characterized in that:

[0087] The main fuel contains ammonia or alcohol as the low GHG fuel.

Claims

1. An engine device comprising: an engine that operates by burning two types of fuel; and a fuel injection valve that can independently inject the two types of fuel into the engine. It is characterized by: When a main fuel containing a low-GHG fuel having lower greenhouse gas emissions than petroleum-based fuels and a hydrocarbon-based auxiliary fuel are injected into the engine using the fuel injection valve as the two fuels, 90% of the total injection amount of the auxiliary fuel is injected before 50% of the total injection amount of the main fuel is injected in one cycle of the engine.

2. The engine device according to claim 1, characterized in that The auxiliary fuel is injected from the radial center of the combustion chamber in a state where a mixed gas of the main fuel and air is generated in the combustion chamber of the engine by injection of the main fuel.

3. The engine device according to claim 1, characterized in that The main fuel is injected from the radial center of the combustion chamber in a state where a mixed gas of the auxiliary fuel and air is generated in the combustion chamber of the engine by injection of the auxiliary fuel.

4. The engine device according to claim 3, characterized in that The main fuel is injected from a radial center of the combustion chamber in a state where the auxiliary fuel is ignited in the combustion chamber of the engine by injection of the auxiliary fuel.

5. The engine device according to claim 1, characterized in that The main fuel is injected multiple times in one cycle of the engine.

6. The engine device according to claim 1, characterized in that The auxiliary fuel is injected multiple times in one cycle of the engine.

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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