Multi-fuel engine

Abstract

To provide a multi-fuel engine that reduces the difficulty of installation work when mounting the engine. [Solution] The present invention is characterized by comprising an engine body having a plurality of cylinders and a plurality of pumps arranged in the engine body, the plurality of pumps including a first pump that pumps a first fuel to be supplied to the combustion chambers of the cylinders, and a second pump that pumps a second fuel different from the first fuel to be supplied to the combustion chambers of the cylinders.

Description

[Technical Field]

[0001] The present invention relates to a multi-fuel engine that can use multiple types of fuel. [Background technology]

[0002] Conventionally, engines that can use multiple types of fuel, such as diesel fuel and methanol, have been known (see Non-Patent Document 1). In such engines, fuel is supplied at high pressure to facilitate ignition in the engine combustion chamber. [Prior art documents] [Patent documents]

[0003] [Non-Patent Document 1] Wartsila, "THE WARTSILA 32 METHANOL ENGINE" brochure, p.4-p.5, [online], [Retrieved May 1, 2024], Internet <URL:https: / / cdn.wartsila.com / docs / default-source / product-files / engines / Wartsila-32-Methanol-leaflet.pdf?utm_source=engines&utm_medium=dfengines&utm_term=w32&utm_content=brochure&utm_campaign=mp-engines-and-generating-sets-brochures> Summary of the Invention [Problem to be solved by the invention]

[0004] When the above engine is mounted on a ship, for example, as shown in Fig. 2, a high-pressure fuel pump 101 for supplying fuel at high pressure to the engine 100 is arranged separately from the engine 100 (in the example shown in Fig. 2, in a fuel preparation space R2 separate from the engine room R1), and high-pressure fuel pump 101 and engine 100 are connected by piping 102. In this case, because high-pressure fuel flows through piping 102, it is necessary to construct piping with a double pipe structure from the viewpoint of preventing leakage to the outside, which makes the construction extremely difficult.

[0005] Therefore, an object of the present invention is to provide a multi-fuel engine that reduces the difficulty of installation work when mounting the engine. [Means for solving the problem]

[0006] The multi-fuel engine of the present invention comprises: an engine body having a plurality of cylinders; a plurality of pumps disposed in the engine body, The plurality of pumps include a first pump that pumps a first fuel to be supplied to the combustion chamber of the cylinder, and a second pump that pumps a second fuel different from the first fuel to be supplied to the combustion chamber of the cylinder.

[0007] With this configuration, the fuel is pressurized and supplied to the cylinders by the pump installed in the multi-fuel engine, so the pressure of the fuel sent to the pump from the side farther from the multi-fuel engine can be reduced, which makes it easier to install piping upstream of the pump.

[0008] In the multi-fuel engine, The number of the first pumps and the number of the second pumps may be set according to the amounts of the first fuel and the second fuel supplied to the cylinders.

[0009] With this configuration, it is possible to prevent the load on some of the pumps from becoming too large.

[0010] In addition, in the multi-fuel engine, The first pump and the second pump may be driven in conjunction with the driving of the multi-fuel engine.

[0011] According to this configuration, the pump configuration can be simplified compared to an electric pump.

[0012] The multi-fuel engine also includes: a first accumulator disposed in a first supply path extending from the first pump to the cylinder and through which the first fuel flows, the first accumulator storing the compressed first fuel; The engine may further include a second accumulator disposed in a second supply path extending from the second pump to the cylinder and through which the second fuel flows, the second accumulator storing the compressed second fuel.

[0013] With this configuration, pressure fluctuations in the fuel supplied to each cylinder can be suppressed. [Effects of the Invention]

[0014] As described above, according to the present invention, it is possible to provide a multi-fuel engine that reduces the difficulty of installation work when mounting the engine. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a schematic diagram for explaining the configuration of a multi-fuel engine according to this embodiment. [Figure 2] FIG. 2 is a schematic diagram for explaining a conventional engine capable of using multiple types of fuel. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, one embodiment of the present invention will be described with reference to FIG.

[0017] The multi-fuel engine according to this embodiment is an engine capable of using multiple types of fuel, for example, heavy oil (first fuel) and methanol (second fuel). This multi-fuel engine is a diesel engine (i.e., an engine that operates by igniting fuel sprayed into a combustion chamber heated to a high temperature by compressing air) and does not use spark plugs. The multi-fuel engine according to this embodiment is a so-called direct injection engine in which fuel is directly injected (sprayed) into the combustion chamber, and is installed, for example, on a ship.

[0018] 1, the multi-fuel engine 1 includes an engine body 2 having a plurality of cylinders 3, and a fuel supply system 6 including a plurality of pumps 5 disposed in the engine body 2. The multi-fuel engine 1 also includes main motion system components.

[0019] The engine body 2 has a cylinder block, a cylinder head, and a crankcase, and the cylinder block and the cylinder head form a cylinder 3. The engine body 2 of this embodiment has a plurality of cylinders 3 (six in the example shown in FIG. 1).

[0020] Intake and exhaust valves are located above each cylinder 3, and the valves of each cylinder 3 are driven to open and close by a camshaft. More specifically, the camshaft is rotated by power (rotational power) transmitted from the crankshaft (described below) via a belt, gears, etc., to open and close each valve.

[0021] The main moving system components include a piston that is arranged in the cylinder 3 so as to be able to reciprocate and that, together with the cylinder 3, forms the combustion chamber 4; a crankshaft that converts the reciprocating motion of the piston into rotational motion for output; a connecting rod that connects the piston and crankshaft; and a flywheel that is arranged on the crankshaft and uses inertia force to suppress rotational irregularities (torque fluctuations) in the multi-fuel engine.

[0022] The multiple pumps 5 include a first pump 51 that pumps heavy oil to be supplied to the combustion chamber 4, and a second pump 52 that pumps methanol to be supplied to the combustion chamber 4. The multiple pumps 5 of this embodiment also include a third pump 53 that pumps lubricating oil to be supplied to the combustion chamber 4.

[0023] Each pump 5 (first pump 51, second pump 52, third pump 53) is driven in conjunction with the driving of the multi-fuel engine 1. The pump 5 of this embodiment is driven by power transmitted from a camshaft for opening and closing the valves of the combustion chambers 4. In other words, each of the pumps 51, 52, 53 is a camshaft-driven pump.

[0024] The numbers of first pumps 51, second pumps 52, and third pumps 53 in the plurality of pumps 5 are set according to the amounts of heavy oil, methanol, and lubricating oil supplied to the cylinders 3 (combustion chambers 4). In the multi-fuel engine 1 of this embodiment, for example, three first pumps 51, two second pumps 52, and one third pump 53 are arranged.

[0025] The first pump 51 pumps out heavy oil at high pressure (for example, up to 150 MPa) that has been supplied at low pressure (for example, up to 1 MPa) from a heavy oil tank arranged in the hull through a pipe P1, that is, pumps the heavy oil.

[0026] The second pump 52 pumps out methanol, which is supplied at low pressure (for example, up to 1 MPa) from a methanol tank arranged in the hull through a pipe P2, at high pressure (for example, up to 60 MPa), that is, pumps out the methanol.

[0027] Furthermore, the third pump 53 pumps out, that is, pumps out, at high pressure (for example, up to 70 MPa), lubricating oil that is supplied at low pressure (for example, up to 1 MPa) from a lubricating oil tank arranged in the hull through the pipe P3.

[0028] In addition to these multiple pumps 5, the fuel supply system 6 has a first supply path 61 that extends from the first pump 51 to the cylinder 3 (combustion chamber 4) and through which heavy oil flows, and a second supply path 62 that extends from the second pump 52 to the cylinder 3 (combustion chamber 4) and through which methanol flows. The fuel supply system 6 of this embodiment also has a third supply path 63 that extends from the third pump 53 to the cylinder 3 (combustion chamber 4) and through which lubricating oil flows.

[0029] The first supply path 61 is a pipeline that supplies heavy oil discharged from the three first pumps 51 to each cylinder 3 (each combustion chamber 4), the second supply path 62 is a pipeline that supplies methanol discharged from the two second pumps 52 to each cylinder 3 (each combustion chamber 4), and the third supply path 63 is a pipeline that supplies lubricating oil discharged from one third pump 53 to each cylinder 3 (each combustion chamber 4).

[0030] The fuel supply system 6 also has a first accumulator 65 that is arranged in the first supply path 61 and stores compressed heavy oil, and a second accumulator 66 that is arranged in the second supply path 62 and stores compressed methanol. The fuel supply system 6 of this embodiment also has a third accumulator 67 that is arranged in the third supply path 63 and stores compressed lubricating oil.

[0031] In the multi-fuel engine 1 configured as above, the fuel to be used is switched by switching the operation mode.

[0032] For example, when the multi-fuel engine 1 is operated in the first operating mode, only heavy oil is supplied to each cylinder 3 (each combustion chamber 4), and the multi-fuel engine 1 is driven by the combustion of this heavy oil.

[0033] At this time, the methanol is pressurized by the second pump 52, but the fuel is not injected because the fuel injection valve is electronically controlled. Also, if the pressure is increased too much, the fuel is relieved to the pump inlet side via a safety valve or the like attached to the pump. Therefore, the methanol is not injected into the combustion chamber.

[0034] On the other hand, when the multi-fuel engine 1 is operated in the second operating mode, heavy oil and methanol are each supplied to each cylinder 3 (each combustion chamber 4). More specifically, in the second operating mode, when methanol is supplied as fuel to the combustion chamber 4, a small amount of heavy oil is also supplied to the combustion chamber 4 at the same time to combust the methanol. At this time, the heavy oil is ignited first in the combustion chamber 4, and the heat generated by the ignition and combustion of this heavy oil causes the methanol to ignite and burn. In this way, in the second operating mode, heavy oil is used as a pilot fuel for igniting methanol.

[0035] The above-described multi-fuel engine 1 includes an engine body 2 having a plurality of cylinders 3, and a plurality of pumps 5 disposed in the engine body 2. The plurality of pumps 5 includes a first pump 51 that pumps heavy oil (first fuel) to be supplied to the combustion chambers 4 of the cylinders 3, and a second pump 52 that pumps methanol (second fuel different from the first fuel) to be supplied to the combustion chambers 4 of the cylinders 3.

[0036] In this way, the fuel is pressurized by the pump 5 arranged in the multi-fuel engine 1 and supplied to the cylinders 3, so the pressure of the fuel sent to the pump 5 from the side away from the multi-fuel engine 1 can be lowered through the pump 5. This makes it possible to reduce the difficulty of piping construction upstream of the pump 5. In other words, even if fuel (heavy oil and methanol) is supplied to the multi-fuel engine 1 at low pressure, the pumps 5 (first pump 51 and second pump 52) can supply high-pressure fuel (heavy oil, methanol) to the cylinders 3 (combustion chambers). Therefore, only low-pressure fuel flows through the fuel supply pipes from the fuel tanks (heavy oil tank and methanol tank) to the multi-fuel engine 1. This eliminates the need to construct double-pipe piping, making it easier to construct the piping.

[0037] Furthermore, in the multi-fuel engine 1 of this embodiment, the multiple pumps 5 also include a third pump 53 that pressurizes the lubricating oil to be supplied to the combustion chamber 4 of the cylinder 3, which reduces the difficulty of installing piping for supplying the lubricating oil from the lubricating oil tank to the multi-fuel engine 1.

[0038] Furthermore, in the multi-fuel engine 1 of this embodiment, the number of first pumps 51 and the number of second pumps 52 are set according to the amounts of heavy oil (first fuel) and methanol (second fuel) supplied to the cylinders 3. Similarly to the number of first pumps and the number of second pumps, the number of third pumps 53 is also set according to the amounts of fuel supplied to the cylinders 3. This makes it possible to prevent the load on some of the pumps 5 from becoming too large.

[0039] Furthermore, in the multi-fuel engine 1 of this embodiment, the first pump 51 and the second pump 52 are driven in conjunction with the driving of the multi-fuel engine 1. The third pump 53 is also driven in conjunction with the driving of the multi-fuel engine 1. With this configuration, the pump configuration can be simplified compared to an electric pump.

[0040] The multi-fuel engine 1 of this embodiment also includes a first accumulator 65 that is disposed in a first supply path 61 that extends from the first pump 51 to the cylinder 3 and through which heavy oil (first fuel) flows, and that stores compressed heavy oil, and a second accumulator 66 that is disposed in a second supply path 62 that extends from the second pump 52 to the cylinder 3 and through which methanol (second fuel) flows, and that stores compressed methanol. The multi-fuel engine 1 also includes a third accumulator 67 that is disposed in a third supply path 63 that extends from the third pump 53 to the cylinder 3 and through which lubricating oil flows, and that stores compressed lubricating oil. This suppresses pressure fluctuations in the fuel and lubricating oil supplied to each cylinder 3.

[0041] The multi-fuel engine of the present invention is not limited to the above-described embodiment, and various modifications may be made without departing from the spirit of the present invention. For example, the configuration of one embodiment may be added to the configuration of another embodiment, or part of the configuration of one embodiment may be replaced with the configuration of another embodiment. Furthermore, part of the configuration of one embodiment may be deleted.

[0042] Furthermore, although the multi-fuel engine 1 of the above embodiment uses heavy oil (first fuel) and methanol (second fuel) as fuel, the present invention is not limited to this configuration. As a so-called carbon-neutral fuel (second fuel), ethanol, methanol, ammonia, hydrogen, etc. may be used instead of methanol. Furthermore, as a fuel (first fuel) for igniting and burning the fuel, biofuel, etc. may be used instead of heavy oil. Furthermore, three or more types of fuel may be used.

[0043] Furthermore, although the multi-fuel engine 1 in the above embodiment is a direct injection engine, the present invention is not limited to this configuration. The multi-fuel engine 1 may be a port injection engine. Furthermore, the configuration may be such that direct injection and port injection are different for each type of fuel supplied to the cylinder 3 (combustion chamber 4).

[0044] Furthermore, although the multi-fuel engine 1 in the above embodiment is a diesel engine (an engine without spark plugs), the multi-fuel engine 1 is not limited to this configuration. The multi-fuel engine 1 may also be an engine in which fuel supplied to the combustion chamber 4 is ignited by spark plugs.

[0045] Furthermore, in the multi-fuel engine 1 of the above embodiment, each pump 5 is driven by a camshaft, but this configuration is not limiting. Each pump 5 may be configured to receive power from the crankshaft via a plurality of gears, belts, chains, or the like. That is, each pump 5 may be configured to be driven in conjunction with the drive of the multi-fuel engine 1. Each pump 5 may be configured to be driven by a control unit such as a CPU. Each pump 5 may also be an electric pump, or the like. That is, the pump 5 may be configured to be disposed in the engine main body 2.

[0046] Furthermore, the multi-fuel engine 1 of the above embodiment has the third pump 53 and the third supply path 63, and is configured so that lubricating oil is supplied to each combustion chamber 4 when the multi-fuel engine 1 is running, but is not limited to this configuration. The multi-fuel engine 1 may also have a configuration that does not include the third pump 53 and the third supply path 63.

[0047] Furthermore, although the multi-fuel engine 1 in the above embodiment is mounted on a ship, it may be mounted on other vehicles or placed in a building, etc. Furthermore, the multi-fuel engine 1 may be used to drive a vehicle, or may be used for power generation, etc.

[0048] Furthermore, in the multi-fuel engine 1 of the above embodiment, fuel discharged from a plurality of pumps (for example, the first pump 51) that pump the same type of fuel is stored in a common accumulator (for example, the first accumulator 65) and then supplied to all of the cylinders 3 (combustion chambers 4), respectively, but this configuration is not limiting. For example, a configuration in which one of the two first pumps 51 supplies the first fuel to two of the cylinders 3, and the other of the two first pumps supplies the first fuel to the remaining cylinder 3, etc., is also possible.

[0049] Furthermore, for example, when the multi-fuel engine 1 is operated in the first operating mode, fuel (heavy oil) is supplied to six (all) of the cylinders 3, and when it is operated in the second operating mode, fuel (heavy oil and methanol) is supplied to three (some) of the cylinders 3; that is, the number of cylinders 3 used may differ between the first operating mode and the second operating mode.

[0050] Furthermore, in the multi-fuel engine 1 of the above embodiment, the number of cylinders 3 and the number of pumps 5 are the same, but they may be different.

[0051] Furthermore, the specific numbers of first pumps 51, second pumps 52, and third pumps 53 are not limited. It is sufficient that the number of first pumps 51 (three in the above embodiment) is smaller than the number of cylinders 3 (six in the above embodiment). It is also sufficient that the number of second pumps 52 (two in the above embodiment) is smaller than the number of cylinders 3. This allows the number and arrangement of pumps 5 to be set arbitrarily depending on the target performance of the multi-fuel engine 1. [Explanation of symbols]

[0052] 1...multi-fuel engine, 2...engine body, 3...cylinder, 4...combustion chamber, 5...pump, 51...first pump, 52...second pump, 53...third pump, 6...fuel supply system, 61...first supply path, 62...second supply path, 63...third supply path, 65...first accumulator, 66...second accumulator, 67...third accumulator, 100...engine, 101...high-pressure fuel pump, 102...piping, P1, P2, P3...piping, R1...engine compartment, R2...fuel preparation space

Claims

1. an engine body having a plurality of cylinders; a plurality of pumps disposed in the engine body, the plurality of pumps including a first pump that pumps a first fuel for delivery to the combustion chambers of the cylinders, and a second pump that pumps a second fuel different from the first fuel for delivery to the combustion chambers of the cylinders.

2. 2. The multi-fuel engine according to claim 1, wherein the number of the first pumps and the number of the second pumps are set according to the amounts of the first fuel and the second fuel supplied to the cylinders.

3. 3. The multi-fuel engine according to claim 1, wherein the first pump and the second pump are driven in conjunction with the driving of the multi-fuel engine.

4. a first accumulator disposed in a first supply path extending from the first pump to the cylinder and through which the first fuel flows, the first accumulator storing the compressed first fuel; 3. The multi-fuel engine according to claim 1, further comprising: a second accumulator arranged in a second supply path extending from the second pump to the cylinder and through which the second fuel flows, the second accumulator storing the compressed second fuel.

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