Marine engine

Abstract

To provide a marine engine with improved efficiency compared to conventional engines.SOLUTION: A marine engine uses a fuel gas as fuel, and comprises a plurality of cylinders, a gas valve for supplying the fuel gas to the cylinders, an air intake port for supplying air into the cylinders, and an exhaust port for discharging the air in the cylinders. The cylinder has a piston, a rod, and a main combustion chamber above the piston. The marine engine further comprises a plurality of auxiliary chamber units that are connected to the main combustion chambers of the cylinders and equipped with an ignition device.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a gas-fueled marine engine. [Background technology]

[0002] Traditionally, heavy oil has been the standard fuel for ships. Burning heavy oil releases large amounts of nitrogen oxides (NOx), which cause air pollution. As a result, the International Maritime Organization (IMO) has imposed restrictions on NOx emissions. To meet these restrictions, there has been a trend toward converting fuel to gas fuels such as liquefied natural gas (LNG), which emits less NOx than heavy oil. Therefore, there is growing interest in maximizing the efficiency of gas engines that use gas fuel as combustion fuel.

[0003] Conventional gas engines are configured to introduce a mixture of main fuel gas and air supplied through a main fuel gas passage into the main combustion chamber of the engine, and to eject an ignition flame generated in an auxiliary chamber into the main combustion chamber to ignite and burn the main fuel gas, and to continuously supply auxiliary fuel gas, which has a greater calorific value than the main fuel gas, into the auxiliary chamber to generate the ignition flame (see Patent Document 1).

[0004] However, in this prior art (see Patent Document 1), if the ignition device in the pre-combustion chamber fails to ignite due to an error, the engine will not start, and if the air-fuel mixture in the main combustion chamber spontaneously ignites before flame propagation, knocking will occur, resulting in serious problems that impair engine efficiency.In addition, gas fuels emit less carbon dioxide and NOx than heavy oil, but they also have the problem of lower engine efficiency.

[0005] Another issue with gas engines is that when gas is compressed in the combustion chamber and becomes hot, the gas fuel can spontaneously ignite in unburned areas, which can easily cause knocking. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 2005-171975 Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention has been proposed in view of the above-mentioned problems of the prior art, and aims to provide a marine engine that improves gas engine efficiency and suppresses the occurrence of knocking. [Means for solving the problem]

[0008] One aspect of the marine engine according to the present invention is a gas-fueled marine engine comprising a plurality of cylinders, a gas valve for supplying fuel gas to the cylinders, an air inlet port for supplying air into the cylinders, and an exhaust port for discharging the air from the cylinders, wherein the cylinders each have a piston, a rod, and a main combustion chamber above the piston, and the engine further comprises a plurality of sub-chamber units connected to the main combustion chambers of the cylinders and equipped with an ignition device.

[0009] With this configuration, the fuel gas sent into the cylinder can be used as the combustion fuel for operating the marine engine, thereby reducing NOx emissions compared to using heavy oil as the combustion fuel. Furthermore, the auxiliary combustion chamber unit has an ignition device, which generates a strong jet flame in the auxiliary combustion chamber to ignite and burn the fuel gas in the main combustion chamber. This allows for stable ignition and combustion, improving engine efficiency.

[0010] In addition, by providing multiple auxiliary chamber units each equipped with an ignition device, multiple flames are supplied to the main combustion chamber, shortening the distance the flame propagates within the main combustion chamber compared to a single flame, thereby improving engine efficiency and suppressing spontaneous ignition in unburned areas, thereby suppressing knocking.

[0011] This marine engine is characterized in that the air intake port is arranged to generate a swirl flow in the main combustion chamber within the cylinder, a jet flame is generated by the ignition device of the auxiliary combustion chamber unit, the flame is supplied into the main combustion chamber, and the flame and the swirl flow cause the flame to propagate within the main combustion chamber.

[0012] With this configuration, the swirl flow promotes flame propagation within the main combustion chamber, allowing the flame to circulate efficiently and quickly within the main combustion chamber, igniting the fuel gas and stabilizing flame combustion. Furthermore, because flame propagation and ignition are completed before the fuel gas in the main combustion chamber spontaneously ignites, knocking can be suppressed. Here, the flame serves as a flame source that burns the fuel gas in the main combustion chamber.

[0013] This marine engine is characterized in that at least two auxiliary combustion chamber units are connected to the main combustion chamber of the cylinder, and each of the two auxiliary combustion chamber units is equipped with the ignition device.

[0014] With this configuration, at least two flames can be generated within the main combustion chamber, which shortens the distance and time required for flame propagation within the main combustion chamber compared to when there is only one, improving the efficiency of flame propagation and suppressing knocking. Furthermore, even if one of the pre-combustion chamber units is unable to generate a flame due to a malfunction or other reason, the other pre-combustion chamber units can generate a flame, providing redundancy that allows the engine to continue operating.

[0015] This marine engine is characterized in that jet flames are generated by the ignition devices of the two auxiliary combustion chamber units, two flames are supplied into the main combustion chamber, and the two flames and the swirl flow cause the flames to propagate within the main combustion chamber.

[0016] With this configuration, the flame propagation distance is shorter with two flames than with one flame, and the flame propagates faster within the main combustion chamber, improving combustion efficiency and suppressing knocking. Furthermore, even if one pre-combustion chamber unit is unable to generate a flame due to a malfunction or other reason, the other pre-combustion chamber unit can generate a flame, providing redundancy so that the engine can continue to operate.

[0017] This marine engine is characterized in that the two sub-chamber units are arranged opposite each other when the cylinder is viewed from above.

[0018] With this configuration, the jet flames from the two sub-chambers equally share the distance that the flames must propagate within the main combustion chamber, resulting in the fastest flame propagation of any two flames, enabling efficient flame propagation and suppression of knocking.

[0019] This marine engine is characterized in that the two sub-chamber units are arranged in the path of the swirl flow when the cylinder is viewed from above.

[0020] With this configuration, the jet flames in the two sub-chambers are carried by the swirl flow, promoting flame propagation in the main combustion chamber, improving the efficiency of flame propagation and suppressing knocking.

[0021] This marine engine is characterized by being a four-stroke cycle engine.

[0022] This configuration provides stable output characteristics even at low revolutions compared to a two-stroke cycle engine, allowing for smooth operation across the entire load range, and is therefore suitable for improving engine efficiency, which is the objective of the present invention.

[0023] The marine engine is characterized in that the cylinder further includes a pressure sensor that measures the pressure in the main combustion chamber.

[0024] With this configuration, the pressure sensor can measure and monitor the pressure inside the main combustion chamber, allowing the state of the fuel gas inside the main combustion chamber to be understood, and the supply of fuel gas and ignition timing can be controlled, thereby improving the efficiency of the gas engine.

[0025] The marine engine further includes a combustion analysis device connected to the pressure sensor and a control device that controls the engine, and the control device and the combustion analysis device control the ignition timing of the sub-chamber unit.

[0026] This configuration allows the ignition timing in the auxiliary combustion chamber to be controlled according to the pressure in the main combustion chamber, thereby improving engine efficiency.

[0027] This marine engine is characterized in that the ignition timing in the sub-chamber unit is controlled for each of a plurality of cylinders.

[0028] This configuration allows the ignition timing of each of the multiple cylinders to be controlled individually, thereby enabling the ignition timing to be controlled to optimize combustion in each cylinder while taking into account the condition and individual differences of each cylinder, thereby improving engine efficiency.

[0029] This marine engine is characterized in that the ignition timing control includes means for acquiring pressure waveform data using the pressure sensor, means for performing frequency analysis on the pressure waveform data, means for calculating knocking intensity from the frequency analysis, and means for controlling the ignition timing based on the calculated knocking intensity.

[0030] According to this configuration, the fuel gas in the pre-chamber is ignited at the timing when the time required for flame propagation is shortest, thereby generating a jet flame, thereby making it possible to suppress knocking and improve engine efficiency.

[0031] This marine engine is characterized by including a control means for controlling the flow of lean gas from the main combustion chamber into the auxiliary combustion chamber, which has a rich gas atmosphere, after the completion of flame injection from the auxiliary combustion chamber unit to the main combustion chamber, and for controlling the mixing of the rich gas and lean gas within the auxiliary combustion chamber unit.

[0032] This configuration enables stable operation even when the main combustion chamber is in a lean state. Specifically, when the pre-chamber becomes a rich gas atmosphere after the supply of fuel gas to the pre-chamber is stopped, lean gas flows in from the main combustion chamber, and the rich gas and lean gas are mixed uniformly in the pre-chamber. This stabilizes the gas concentration, which stabilizes combustion and allows operation to continue even when the main combustion chamber becomes lean, achieving stable operation.

[0033] The marine engine is characterized in that the gas valve includes a main gas valve that supplies fuel gas to the main combustion chamber of the cylinder, and a pre-chamber gas valve that supplies fuel gas to the pre-chamber unit.

[0034] According to this configuration, gas can be independently injected into the sub-chamber, which generates a powerful jet flame and enables stable ignition and combustion of the fuel gas in the main combustion chamber.

[0035] The marine engine is characterized by further comprising a reversing gear.

[0036] With this configuration, the reverse gear directly connects to the propeller, eliminating gear losses and allowing for efficient use of engine output. Furthermore, compared to a reduction gear with a complex structure, component failures are less likely to occur, reducing maintenance costs.

[0037] The marine engine further includes a fuel injection nozzle connected to the cylinder and a passage for supplying diesel fuel to the fuel injection nozzle, and is characterized by having a diesel operating mode in which the marine engine is operated using the diesel fuel.

[0038] With this configuration, even if fuel gas cannot be supplied, the engine can be operated using diesel fuel.

[0039] This marine engine may be configured to include a plurality of pilot injectors instead of a plurality of sub-chamber units. [Effects of the Invention]

[0040] According to the configuration of the present invention, a marine engine uses gas as fuel and has improved engine efficiency compared to conventional engines. [Brief explanation of the drawings]

[0041] [Figure 1] 1 is a diagram showing the overall configuration of a marine engine according to an embodiment of the present invention; [Figure 2] FIG. 2 is a cross-sectional view showing the internal structure of a cylinder of a marine engine. [Figure 3] This is an enlarged schematic diagram of the main combustion chamber and auxiliary combustion chamber in the internal structure of the cylinder. [Figure 4] FIG. 3 is an explanatory diagram showing a swirl flow in the main combustion chamber. [Figure 5] FIG. 2 is an explanatory diagram showing flame propagation in the main combustion chamber. [Figure 6] FIG. 10 is an explanatory diagram showing the state of gas in the auxiliary chamber. [Figure 7] 10 is a graph comparing the effect of lean control in the auxiliary chamber with normal control. [Figure 8] FIG. 2 is a block diagram illustrating a control unit of the marine engine. [Figure 9] 1 is a chart showing the state of each cylinder. [Figure 10] FIG. 1 is a block diagram showing a schematic configuration of a portion of a marine engine. [Figure 11] FIG. 6 is a schematic diagram of the internal structure of a cylinder in a marine engine according to a second embodiment. [Figure 12] FIG. 10 is a schematic view of the internal structure of a cylinder in a marine engine according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0042] A marine engine according to the present invention will be described below with reference to the drawings, but the present invention is not limited to this embodiment. Furthermore, the components in the following embodiment include those that are easily replaceable by those skilled in the art, or those that are substantially identical. Furthermore, the configurations described below can be combined as appropriate. Furthermore, various omissions, substitutions, or modifications of the configuration can be made without departing from the spirit of the present invention.

[0043] First Embodiment (Engine overall configuration) Fig. 1 is a diagram showing the overall configuration of a marine engine according to one embodiment of the present invention. Fig. 2 is a cross-sectional view cut so that the internal structure of the cylinder can be seen. Fig. 3 is an enlarged schematic diagram showing the main combustion chamber and auxiliary combustion chamber in the internal structure of the cylinder.

[0044] As shown in Fig. 1, the engine 1 of this embodiment is a four-stroke marine engine equipped with six cylinders 10. As shown in Figs. 2 and 3, each cylinder 10 includes a piston 20 and a rod 21. When the piston 20 moves up and down through the action of the rod 21, the main combustion chamber 50, which is the space above the piston 20, repeatedly undergoes compression and expansion.

[0045] When the main combustion chamber 50 is compressed, the fuel gas inside the chamber is compressed into a high-temperature, high-pressure state and ignites, causing combustion and explosion within the main combustion chamber 50. This energy is converted into kinetic energy and becomes a power source.

[0046] (Cylinder configuration) 3, the cylinder 10 is equipped with an intake port 30 that supplies air to the main combustion chamber 50 and an exhaust port 40 that discharges the air. Fuel gas is supplied to an intake pipe connected to the intake port 30 via a main gas valve 81, and a mixture of fuel gas and air is supplied to the main combustion chamber 50. As a result, the mixture of fuel gas and air is ignited in the main combustion chamber 50, causing an explosion. The intake port 30 and the exhaust port 40 are arranged so as to generate a swirl flow in the main combustion chamber 50 (see FIG. 4).

[0047] The cylinder 10 is further provided with a pressure sensor 90, which is configured to measure and monitor the pressure inside the main combustion chamber 50. The pressure sensor 90 is connected to a combustion analyzer 91, which will be described later, and the combustion analyzer 91 is connected to an engine control unit 92 and a control device 93 in that order (see FIG. 7).

[0048] Two auxiliary chamber units 60 are connected to the piston 10. The auxiliary chamber unit 60 is connected to the main combustion chamber 50 of the piston 10 and includes an auxiliary chamber 61 that supplies flame to the main combustion chamber 50, and a spark plug 62 that serves as an ignition device. Fuel gas is supplied into the auxiliary chamber 61 via an auxiliary chamber gas valve 82 and ignited by the spark plug 62, generating a jet flame in the auxiliary chamber 61. This jet flame is then supplied from the auxiliary chamber 61 to the main combustion chamber 50, igniting the fuel gas in the main combustion chamber 50.

[0049] Figure 4 is a schematic diagram of the interior of the main combustion chamber 50 as seen from above. As shown in Figure 4, the flow from the intake port 30 to the exhaust port 40 generates a swirl flow, i.e., a horizontally swirling flow, within the main combustion chamber 50. The main combustion chamber 50 of the cylinder 10 is circular when viewed from above, and flame ports 51 leading from the auxiliary chamber 61 to the main combustion chamber 50 are arranged opposite the center of the circle.

[0050] The jet flame generated in the auxiliary chamber 61 is then injected into the main combustion chamber 50 through the flame port 51 of the main combustion chamber 50. This flame propagates while swirling horizontally along the swirl flow, spreading throughout the entire main combustion chamber 50 (see FIG. 5). When the piston 20 rises in the cylinder and the pressure and temperature of the mixture of fuel gas and air in the main combustion chamber 50 increase, this flame ignites the fuel gas in the main combustion chamber 50, causing combustion and explosion.

[0051] As described above, the two auxiliary chambers 61 are arranged opposite to the main combustion chamber 50 and are efficiently arranged to shorten the propagation distance, so that the two jet flames generated by the two auxiliary chambers 61 are carried by the swirl flow and efficiently propagate throughout the main combustion chamber 50. This improves engine efficiency and also makes it possible to suppress knocking caused by accidental combustion in unburned areas.

[0052] Furthermore, even if one of the auxiliary chamber units 60 malfunctions due to a problem or the like, although engine efficiency will decrease, it is possible to continue operation using the other auxiliary chamber unit 60. Furthermore, although this embodiment is configured with two auxiliary chamber units 60, it is also possible to configure with three or four.

[0053] (Combustion process in the main combustion chamber) Combustion in the cylinder 10 described above occurs in the following steps: First, when the piston 20 in the cylinder descends, a mixture of fuel gas and air flowing from the main gas valve 81 into the air supply pipe is supplied into the main combustion chamber 50 through the intake port 30 (step 1).

[0054] Next, the piston 20 rises, compressing the inside of the main combustion chamber 50 and increasing the pressure and temperature of the mixture of fuel gas and air, and jet flames from the two auxiliary chambers 61 are injected into the main combustion chamber 50. Then, the two flames ride the swirl flow and move through the main combustion chamber 50, igniting the fuel gas in the main combustion chamber 50, causing combustion and explosion in the main combustion chamber 50 (Step 2).

[0055] Then, as the fuel gas burns and explodes, the piston 20 descends (step 3).

[0056] Next, the exhaust port 40 is opened, and the gas in the main combustion chamber 50 is exhausted from the exhaust port 40 (step 4).

[0057] The engine 1 operates by repeating the four-cycle flow from step 1 to step 4 for each of the six cylinders 10.

[0058] (Combustion process in the pre-chamber unit) On the other hand, as shown in FIG. 6, in the auxiliary chamber unit 60, before the fuel gas is supplied, the interior of the auxiliary chamber 61 is in a very lean state (immediately before the fuel gas is injected).

[0059] When fuel gas is supplied into the auxiliary chamber 61, the auxiliary chamber 61 is filled with fuel gas and becomes in a very rich state (when fuel gas injection ends).

[0060] Next, as the piston 20 rises in the cylinder 10 and the main combustion chamber 50 is compressed (step 2 of the main combustion chamber), the lean gas in the main combustion chamber 50 flows into the auxiliary chamber 61 and is mixed with the fuel gas in the auxiliary chamber 61, forming a homogeneous gas mixture that is moderately richer than the surrounding air (just before ignition in the auxiliary chamber).

[0061] At this time, the spark plug 62 of the auxiliary chamber unit 60 ignites the fuel gas in the auxiliary chamber 61 to generate a jet flame, and supplies this flame into the main combustion chamber 50 (step 2 of the main combustion chamber).

[0062] By controlling the fuel gas in the auxiliary combustion chamber 61 and the main combustion chamber 50 in this manner (lean control), the engine 1 of this embodiment can operate stably even in a lean state. As a result, by using a mixture gas that is leaner than normal, i.e., because the fuel gas concentration is lower and the amount of fuel gas is smaller than in normal control, the ignition delay and combustion period of the fuel gas throughout the main combustion chamber 50 can be shortened (see FIG. 7). Note that FIG. 7(a) is a graph showing the ignition timing, ignition delay, and combustion period for normal control and the lean control of this embodiment. FIG. 7(b) is a graph showing the efficiency under normal control and lean control.

[0063] Therefore, by using the lean control of this embodiment, combustion and engine operation can be performed in a leaner state than in the case of normal control, thereby reducing the amount of fuel gas used and improving fuel economy.

[0064] The above-mentioned control is realized by the following configuration: As shown in Fig. 8, a pressure sensor 90 in the main combustion chamber 50 monitors the pressure inside the main combustion chamber 50, and a combustion analyzer 91, an engine control unit 92, and a control device 93, which are connected in this order to the pressure sensor 90, control the amount of fuel gas supplied, the supply timing, the ignition timing, etc.

[0065] For example, the ignition timing is determined by measuring the pressure inside the main combustion chamber 50 with a pressure sensor 90, sending the pressure data to a combustion analyzer 91, which calculates pressure waveform data. The combustion analyzer 91 then performs frequency analysis based on the pressure waveform data, calculates the knocking intensity, and determines the ignition timing so that a certain knock control limit is reached. This ignition timing data is sent to an engine control unit 92 and a control device 93, which controls the ignition timing in the sub-combustion chamber unit 60.

[0066] This configuration allows appropriate ignition timing to be set for each cylinder, eliminating the effects of unevenness due to cylinder position and achieving optimal combustion in all cylinders, thereby improving thermal efficiency and engine efficiency.

[0067] Like a computer, the combustion analysis device 91, engine control unit 92, and control device 93 are equipped with a CPU, memory, storage devices such as SSDs and HDDs, output devices, input devices, etc. (not shown), which enable the above calculations and controls to be performed.

[0068] Furthermore, while it goes without saying that it is preferable to use fuel gas control in the pre-chamber unit 60 as in this embodiment, a configuration without this control is also possible, in which case ordinary fuel gas is supplied to each of the main combustion chamber and the pre-chamber, as with normal fuel control. Even if this control is not used, by providing two pre-chamber units 60 in the main combustion chamber 50, it is possible to obtain certain effects, such as improved engine efficiency due to improved flame propagation efficiency.

[0069] 10, the engine 1 of this embodiment is connected to the propeller 3 via the reverse gear 2. By connecting the reverse gear 2 to the engine 1, rotation can be transmitted stably and without loss to the propeller 3. Furthermore, fuel gas is supplied to the engine 1 in a state compressed by the gas compressor 4.

[0070] Second Embodiment Next, a second embodiment will be described. The main difference between the second embodiment and the first embodiment is that a pilot injection unit is provided instead of a sub-chamber unit. Therefore, for the second embodiment, only the parts that differ from the first embodiment will be described, and similar components will be denoted by similar reference numerals and will not be described as appropriate.

[0071] Fig. 11 is a schematic diagram of an engine 100 equipped with pilot injection according to the second embodiment. In Fig. 11, the cylinder 10 of the engine 100 has a main combustion chamber 50 and two pilot injectors 160. Fuel gas is injected from the main gas valve 81 into the air flowing in the intake port 30, and a mixture of gas and air is supplied into the main combustion chamber 50, generating a swirl flow.

[0072] Furthermore, the injection of liquid fuel, particularly pilot fuel, supplied for the purpose of ignition is referred to as pilot injection. The pilot fuel is sent from the pilot fuel pipe 180 to the two pilot injectors 160 via the pilot fuel valve 182 at the timing when the gas mixture is compressed in the main combustion chamber 50, and a pilot flame is injected into the main combustion chamber 50. This ignites the gas mixture of gas fuel and air in the main combustion chamber 50, causing combustion and explosion.

[0073] <Third embodiment> Next, a third embodiment will be described. The main difference between the third embodiment and the first embodiment is that the third embodiment includes a diesel fuel mode in which the fuel is switched from fuel gas to diesel fuel. Therefore, for the third embodiment, only the parts that differ from the first embodiment will be described, and similar components will be denoted by the same reference numerals and will not be described as appropriate.

[0074] The engine 200 of the third embodiment can have redundancy in the engine by using diesel fuel instead of gas fuel in an emergency when fuel gas cannot be supplied, for example.

[0075] 12 is a schematic diagram of an engine with a diesel fuel operating mode. As shown in FIG. 12, engine 200 further includes a fuel injection nozzle 260 that compresses and injects diesel fuel into the main combustion chamber of cylinder 10.

[0076] Air is supplied to the main combustion chamber 50 in the cylinder 10 through the intake port 30. The piston moves down during this intake. Next, the piston in the main combustion chamber 50 moves up, compressing the air in the main combustion chamber 50.

[0077] At this time, diesel fuel is supplied from a diesel fuel pipe 280 for supplying diesel fuel to a fuel injection nozzle 260 via a diesel fuel valve 281. Then, the atomized diesel fuel compressed in the main combustion chamber 50 is injected into the high-temperature, high-pressure air in the main combustion chamber 50, causing the diesel fuel to self-ignite.

[0078] Fuel injection times and other factors are roughly the same as those of a normal diesel engine under high load, achieving moderate diesel combustion.

[0079] The switching between diesel fuel and fuel gas and the operation mode can be configured to be performed manually or automatically by the control device 93, for example.

[0080] <Other embodiments> While the preferred embodiment of the present invention has been described above with reference to the drawings, various additions, modifications, and deletions are possible without departing from the spirit of the present invention. For example, in this embodiment, two auxiliary combustion chamber units 60 are arranged for one main combustion chamber 50, but this is not limiting, and a configuration with three or four auxiliary combustion chamber units is also possible. [Explanation of symbols]

[0081] 1 engine 2 Reverse gear 3 propellers 4 Compressor 10 cylinders 20 pistons 30 Air supply port 40 exhaust port 50 Main combustion chamber 60 Antechamber Unit 61 Antechamber 62 Spark plug 80 Gas Pipe 81 Main gas valve 82 Sub-chamber gas valve 90 Pressure Sensor 91 Combustion analyzer 92 Engine Control Unit 93 Control Device 100 Engine 110 cylinders 160 Pilot Injector 180 Pilot fuel line 182 Fuel valve 200 Engine 210 cylinders 260 Fuel injection nozzle 280 Diesel fuel pipe 281 Diesel fuel valve

Claims

1. A marine engine that uses fuel gas as fuel, A plurality of cylinders; a gas valve for supplying fuel gas to the cylinder; an air supply port for supplying air into the cylinder; an exhaust port for discharging air from the cylinder; The cylinder is a piston, a rod, and a main combustion chamber above the piston; The engine further comprises a plurality of sub-combustion chamber units connected to the main combustion chambers of the cylinders and equipped with ignition devices. Marine engines.

2. The intake port is provided so as to generate a swirl flow in the main combustion chamber within the cylinder, A jet flame is generated by the ignition device of the auxiliary combustion chamber unit, and the flame is supplied into the main combustion chamber; The flame and the swirl flow cause flame propagation within the main combustion chamber.

2. A marine engine according to claim 1.

3. At least two sub-chamber units are connected to the main combustion chamber of the cylinder, The two sub-chamber units each include the ignition device.

3. A marine engine according to claim 2.

4. generating jet flames by the ignition devices of the two auxiliary combustion chamber units, and supplying two flames into the main combustion chamber; The method is characterized in that the flame is propagated in the main combustion chamber by the two flames and the swirl flow.

4. A marine engine according to claim 3.

5. The two sub-chamber units are arranged opposite to each other when viewed from above the cylinder.

5. A marine engine according to claim 4.

6. The two sub-chamber units are arranged in a path of the swirl flow when the cylinder is viewed from above.

8. A marine engine according to claim 7.

7. It is a four-stroke cycle engine, 2. A marine engine according to claim 1.

8. The cylinder is The invention further comprises a pressure sensor for measuring the pressure of the main combustion chamber.

2. A marine engine according to claim 1.

9. a combustion analysis device connected to the pressure sensor; a control device that controls the engine, The control device and the combustion analysis device control the ignition timing of the sub-chamber unit.

9. A marine engine according to claim 8.

10. The ignition timing in the sub-chamber unit is controlled for each of a plurality of cylinders.

10. A marine engine according to claim 9.

11. The control of the ignition timing means for acquiring pressure waveform data by the pressure sensor; means for performing frequency analysis on the pressure waveform data; means for calculating knocking intensity from the frequency analysis; The ignition timing is controlled based on the calculated knocking intensity. A marine engine according to claim 10.

12. After the flame injection from the auxiliary combustion chamber unit to the main combustion chamber is completed, Lean gas flows from the main combustion chamber into the auxiliary combustion chamber unit, which has a rich gas atmosphere. A control means is provided for mixing rich gas and lean gas in the auxiliary chamber unit. The gas engine according to claim 1.

13. The gas valve is a main gas valve for supplying fuel gas to the main combustion chamber of the cylinder; a pre-chamber gas valve for supplying fuel gas to the pre-chamber unit; characterized in that it comprises 2. A marine engine according to claim 1.

14. Further comprising a reversing gear, 2. A marine engine according to claim 1.

15. a fuel injection nozzle connected to the cylinder; a passage for supplying diesel fuel to the fuel injection nozzle; Furthermore, The present invention is characterized in that it has a diesel operation mode in which the device is operated using the diesel fuel.

2. A marine engine according to claim 1.

16. A plurality of pilot injectors are provided instead of the plurality of sub-chamber units. A marine engine according to any one of claims 1 to 15.

Images