Internal combustion engine

Abstract

The invention relates to an internal combustion engine for propulsion of a marine vessel, the internal combustion engine having at least one cylinder and comprising a fuel supply system, the fuel supply system comprising a first cylinder fuel supply passage comprising a first main valve and a first secondary valve arranged upstream of the first main valve, and a second cylinder fuel supply passage comprising a second main valve and a second secondary valve arranged upstream of the second main valve, wherein a first pressure sensor providing a first pressure signal is arranged between the first main valve and the first secondary valve, and a second pressure sensor providing a second pressure signal is arranged between the second main valve and the second secondary valve, and the internal combustion engine further comprises a comparison unit comparing the first pressure signal with the second pressure signal for detecting a difference between the first pressure signal and the second pressure signal. The invention further relates to a leakage detection method for detecting a leakage in a valve in a fuel supply system, and to a computer program product.

Description

Technical Field

[0001] This invention relates to an internal combustion engine for propelling a vessel, the engine having at least one cylinder. The invention also relates to a leak detection method for detecting valve leaks in a fuel supply system, and a computer program product. Background Technology

[0002] When designing vessels (such as container ships and tankers), the primary focus is on onboard safety and prevention of environmental damage, while operating in a cost-effective manner. For safe and cost-effective operation, it is crucial to detect any engine component failures before serious defects necessitate replacement and before these failures affect other engine parts.

[0003] Tiny leaks in fluid passages, valves, and other similar locations are difficult to detect, yet they are significant because, although the leak is small, the damage is minimal. Therefore, only minor repairs or replacement of the leaking valve are needed, without the need to replace related parts. However, if a small leak goes undetected, repairs become much more arduous and expensive, and the vessel may even become inoperable during the repair process.

[0004] DK201970373 shows an internal combustion engine used to propel ships. Summary of the Invention

[0005] One object of the present invention is to overcome, in whole or in part, the aforementioned disadvantages and defects of the prior art. More specifically, one object of the present invention is to provide an improved internal combustion engine that can detect any leakage in valves of the fuel supply system in a simple manner to avoid serious damage and potential safety hazards, while still saving costs.

[0006] The foregoing objectives, as well as many other objectives, advantages, and features that are apparent from the following description, are achieved by means of an internal combustion engine for ship propulsion, having at least one cylinder and comprising:

[0007] - Fuel supply system, including:

[0008] - The fuel supply passage for the first cylinder includes a first main valve and a first-stage valve disposed upstream of the first main valve, and

[0009] - The fuel supply passage for the second cylinder includes a second main valve and a second-stage valve arranged upstream of the second main valve.

[0010] Specifically, a first pressure sensor providing a first pressure signal is arranged between the first main valve and the first stage valve, and a second pressure sensor providing a second pressure signal is arranged between the second main valve and the second stage valve.

[0011] The internal combustion engine also includes a comparison unit that compares a first pressure signal with a second pressure signal to detect the difference between the two pressure signals.

[0012] Moreover, at least one cylinder can be the first cylinder, and the internal combustion engine can also include a second cylinder.

[0013] In addition, the fuel supply passage of the first cylinder supplies fuel to one of the first cylinder and the second cylinder, and the fuel supply passage of the second cylinder supplies fuel to one of the first cylinder and the second cylinder.

[0014] In another type of internal combustion engine for ship propulsion, the internal combustion engine may have at least a first cylinder and a second cylinder, and may include:

[0015] - Fuel supply system, which includes:

[0016] - A first cylinder fuel supply passage for supplying fuel to one of the first and second cylinders, comprising a first main valve and a first-stage valve disposed upstream of the first main valve, and

[0017] - A second cylinder fuel supply passage for supplying fuel to one of the first and second cylinders, comprising a second main valve and a second stage valve located upstream of the second main valve.

[0018] Specifically, a first pressure sensor providing a first pressure signal is arranged between the first main valve and the first stage valve, and a second pressure sensor providing a second pressure signal is arranged between the second main valve and the second stage valve.

[0019] The internal combustion engine also includes a comparison unit that compares a first pressure signal with a second pressure signal to detect the difference between the two pressure signals.

[0020] When an internal combustion engine operates under low load and / or low pressure, the pressure in the fuel supply system does not accumulate to the level seen when the engine operates under high load or high pressure (e.g., 300 bar with the valve closed). Therefore, more traditional leak detection methods are not efficient enough. However, small leaks or malfunctions can be detected by measuring and comparing the pressure, or its representation, between the main and secondary valves in the first and second cylinder fuel supply passages. This is because ambient factors (e.g., low pressure and low load) affect the pressure in the first and second cylinder fuel supply passages equally, respectively, so that the pressure accumulation does not need to be too high to detect small leaks.

[0021] Leaks or faults can be detected by measuring and comparing the pressure or its representation between the main valve and the secondary valve on the fuel supply passage of the first cylinder and the fuel supply passage of the second cylinder, although the leaks or faults are still very small because the pressure signals can be compared. Therefore, even if the pressure signals change, the correlation between them will be very stable, even if the supply pressure changes or other factors around the fuel supply system change.

[0022] This results in an improved internal combustion engine that can easily detect any leaks or malfunctions in the valves of the fuel supply system. This detection can prevent serious damage and safety hazards, meaning the internal combustion engine is more cost-effective because leaking or malfunctioning valves can be repaired or replaced before major damage occurs.

[0023] In known internal combustion engines, leak detection of valves in the fuel supply passage that supplies fuel to the cylinders is performed through various tests, such as volumetric testing, drop testing, curve fitting testing, variation testing, and maximum pressure testing, to detect any leaks or malfunctions at an early stage. In particular, curve fitting testing has proven unsuitable for engines operating under low pressure and low load conditions. This invention requires only one test.

[0024] Furthermore, the fuel supply passage of the first cylinder can be fluidly connected to the first cylinder, and the fuel supply passage of the second cylinder can be fluidly connected to either the first cylinder or the second cylinder.

[0025] Furthermore, the fuel supply passage of the first cylinder can be fluidly connected to the first cylinder for injecting fuel into the first cylinder, and the fuel supply passage of the second cylinder can be fluidly connected to the first cylinder for injecting fuel into the first cylinder, or the fuel supply passage of the second cylinder can be fluidly connected to the second cylinder for injecting fuel into the second cylinder.

[0026] In addition, the fuel supply system may include a main supply channel that is fluidly connected to the fuel supply passage of the first cylinder and the fuel supply passage of the second cylinder.

[0027] In addition, the main supply channel can be located upstream of the fuel supply channel for the first cylinder and the fuel supply channel for the second cylinder.

[0028] In addition, the fuel supply system may include a pump, and the main supply channel may be fluidly connected to the pump for supplying fuel to both the first cylinder fuel supply channel and the second cylinder fuel supply channel.

[0029] In addition, the fuel supply system may include a pressure control valve, and the main supply passage may be fluidly connected to the pressure control valve for controlling the flow of fuel to the first cylinder fuel supply passage and the second cylinder fuel supply passage.

[0030] Furthermore, the first pressure sensor can measure a real-time and / or continuous first pressure signal, and the second pressure sensor can measure a real-time and / or continuous second pressure signal.

[0031] In addition, the fuel can be propane, butane, methanol, methane, ethanol, ethylene, ethane, ammonia, propylene, butene, isobutane, n-butane, hydrogen, kerosene, nitromethane, liquefied petroleum gas, bioethanol, or biodiesel.

[0032] Furthermore, this fuel can be the only fuel supplied to at least one cylinder.

[0033] In addition, the fuel can be a secondary fuel, and the primary fuel can be diesel, gasoline or petroleum.

[0034] In addition, the sulfur content of the primary fuel may be at least 0.05%.

[0035] In addition, the fuel can be liquid or gas.

[0036] Moreover, the opening period of the main valve can be shorter than that of the secondary valve.

[0037] In addition, the secondary valve can be opened before the main valve opens.

[0038] The measurement and comparison methods of this invention enable the monitoring and detection of leaks or malfunctions, particularly in secondary valves, which is very difficult for known systems performing curve-fit tests. When using curve-fit tests, the measured pressure is typically compared to a reference curve; however, external factors such as operation under low load or low pressure will affect the results, requiring a very wide range of difference between the measured pressure and the reference curve to also accommodate engine operation under low load and low pressure. When the range needs to be wide to prevent the engine from unexpectedly stopping, small leaks cannot be detected. Leaks in secondary valves (also known as window valves) can be a potential safety hazard, therefore, detecting such leaks at an early stage is crucial.

[0039] Additionally, the secondary valve may open when the main valve is closed.

[0040] In addition, the secondary valve may close when the main valve is closed.

[0041] Furthermore, when the secondary valve opens, the main valve may open and / or close.

[0042] Furthermore, the first pressure signal can form a first pattern, the second pressure signal can form a second pattern, and the comparison unit can compare the first pattern with the second pattern to detect correlation and verify whether the correlation is within a predetermined range.

[0043] "Association" refers to any statistical relationship between two sets of pressure signal data, such as statistical variance, i.e., any type of association, which refers to the degree of linear correlation between a pair of variables.

[0044] Furthermore, the comparison unit can be a central processing unit (CPU), a control unit, an integrated circuit (e.g., a microchip or chip), a comparison unit, or a hardware- or software-based comparator.

[0045] Furthermore, the comparison unit may include pattern recognition software.

[0046] In addition, the internal combustion engine may also include a third and a fourth cylinder, each of which is supplied with fuel from two fuel supply passages, each of which has a pressure sensor, a secondary valve and a main valve.

[0047] In addition, an internal combustion engine can also include at least six cylinders.

[0048] In addition, the first pressure signal can have a predetermined number of data points within a predetermined time period.

[0049] In addition, the second pressure signal can have a predetermined number of data points within a predetermined time period.

[0050] In addition, the predetermined time period can start from one of the valves' operating positions until the same operating position is reached again.

[0051] Furthermore, the predetermined time period can be from the time the secondary valve closes until the time the secondary valve closes again.

[0052] In addition, the internal combustion engine system may also include a turbocharger located downstream of the internal combustion engine.

[0053] In addition, a turbocharger can include a turbine and a compressor.

[0054] Additionally, the present invention relates to a leakage or malfunction detection method for detecting leakage or malfunction of a valve in a fuel supply system supplying fuel to at least one cylinder of an internal combustion engine, the method comprising:

[0055] -A first pressure signal is measured within a first time period by a first pressure sensor between the first main valve and the first stage valve on the fuel supply passage of the first cylinder of the fuel supply system.

[0056] -The second pressure signal during the first or second time period is measured by a second pressure sensor between the second main valve and the second stage valve on the fuel supply passage of the second cylinder of the fuel supply system, and

[0057] - Compare the first pressure signal with the second pressure signal to detect a leak or malfunction in one of the valves.

[0058] Furthermore, the present invention relates to a computer program product comprising a computer-readable medium storing computer program code, and, when loaded, the computer program product causes a computer to perform a leak or fault detection method.

[0059] In addition, the internal combustion engine can be a large two-stroke internal combustion engine.

[0060] Alternatively, the internal combustion engine can be a large turbocharged two-stroke crosshead type internal combustion engine.

[0061] Furthermore, the internal combustion engine can be a two-stroke or a four-stroke internal combustion engine. Attached Figure Description

[0062] The invention and its many advantages will now be described in more detail with reference to the accompanying drawings, which illustrate some non-limiting embodiments for illustrative purposes.

[0063] Figure 1 A schematic diagram of the fuel supply system for an internal combustion engine is shown.

[0064] Figure 2 A schematic diagram of another fuel supply system for an internal combustion engine is shown.

[0065] Figure 3 A schematic diagram of another fuel supply system for an internal combustion engine is shown.

[0066] Figure 4 A schematic diagram of the first pressure signal and the second pressure signal is shown.

[0067] All accompanying drawings are highly schematic and not necessarily drawn to scale, and they only show the parts necessary to illustrate the invention, while other parts are omitted or merely implied. Detailed Implementation

[0068] Figure 1A schematic diagram of a fuel supply system 4 for an internal combustion engine 1 used to propel a vessel (e.g., a container ship or tanker) is shown. The internal combustion engine 1 can also be a stationary engine. Therefore, the internal combustion engine 1 can be a two-stroke or four-stroke internal combustion engine 1. The internal combustion engine 1 includes a first cylinder 2 and a fuel supply system 4. The fuel supply system 4 includes first cylinder fuel supply passages 5, 5a for supplying fuel to the first cylinder 2 and second cylinder fuel supply passages 5, 5b for supplying fuel to the first cylinder 2. Thus, the first cylinder fuel supply passages 5, 5a are fluidly connected to the first cylinder 2 to inject fuel into the first cylinder 2, and the second cylinder fuel supply passages 5, 5b are fluidly connected to the same first cylinder 2 to inject fuel into the first cylinder 2 at different locations along the periphery of the first cylinder 2. The first cylinder fuel supply passages 5, 5a include first main valves 6, 6a and first stage valves 7, 7a disposed upstream of the first main valves 6, 6a. The second cylinder fuel supply passages 5, 5b include second main valves 6, 6b and secondary stage valves 7, 7b located upstream of the second main valves 6, 6b. Furthermore, the fuel supply system 4 includes first pressure sensors 8, 8a that provide first pressure signals 9, 9a, and these first pressure sensors 8, 8a are arranged to measure the pressure between the first main valves 6, 6a and the first stage valves 7, 7a. Also, the fuel supply system 4 includes second pressure sensors 8, 8b that provide second pressure signals 9, 9b and are arranged to measure the pressure between the second main valves 6, 6b and the second stage valves 7, 7b. The internal combustion engine 1 also includes a comparison unit 10 that compares the first pressure signals 9, 9a and the second pressure signals 9, 9b to detect any difference between the first pressure signals 9, 9a and the second pressure signals 9, 9b, which indicates a leak in one of the valves 6, 6a, 6b, 7, 7a, 7b. Figure 1 As shown by the dashed lines, the comparison unit 10 receives first pressure signals 9 and 9a from the first pressure sensors 8 and 8a, and receives second pressure signals 9 and 9b from the second pressure sensors 8 and 8b.

[0069] Small leaks or malfunctions in main valves 6, 6a, 6b or secondary valves 7, 7a, 7b are difficult to detect, but are important because while the leaks are small, the damage is also minimal, requiring only minor repairs or replacement of the leaking valve. Furthermore, leaks or malfunctions in secondary valves 7, 7a, 7b can pose safety hazards. However, if leaks or malfunctions go undetected due to their small size, repair work becomes much more arduous and expensive, and the vessel may even be rendered inoperable during repairs.

[0070] When the internal combustion engine 1 operates at low load and / or low pressure, the pressure in the fuel supply system 4 will not accumulate to the level seen when the engine operates at high load or high pressure (e.g., 300 bar when valves 6 and 7 are closed). Therefore, more traditional leak detection methods are not efficient enough.

[0071] In known internal combustion engines, various tests are used to detect leaks in valves within the fuel supply passage that supplies fuel to the cylinders, such as volumetric testing, drop testing, curve fitting testing, variation testing, and maximum pressure testing, in order to detect any leaks or malfunctions at an early stage. In particular, curve fitting testing has proven unsuitable for engines operating under low pressure and low load conditions.

[0072] However, small leaks or malfunctions can be detected by measuring and comparing the pressure, or its representation, between the main valve 6 and the secondary valve 7 on both the first cylinder fuel supply passages 5, 5a and the second cylinder fuel supply passages 5, 5b, because ambient factors (such as low load and low pressure) affect the pressure in the first cylinder fuel supply passages 5, 5a and the second cylinder fuel supply passages 5, 5b equally, so that the pressure buildup does not have to be too high to detect small leaks or any malfunctions.

[0073] Leaks or malfunctions can be detected by measuring the pressure, or its representation, between the main valves 6, 6a, 6b and the secondary valves 7, 7a, 7b on both the first cylinder fuel supply passages 5, 5a and the second cylinder fuel supply passages 5, 5b. Although the leakage or malfunction is very small, the pressure signals can be compared, and therefore the correlation between them remains very stable even if the pressure signals 9a, 9b change, regardless of changes in the supply pressure or other factors surrounding the fuel supply system 4. Thus, an improved internal combustion engine 1 is obtained, capable of detecting any leaks or malfunctions in the valves 6, 7 of the fuel supply system 4 in a simple manner. This detection can prevent serious damage and safety hazards, meaning the internal combustion engine 1 is more cost-effective because leaking or malfunctioning valves 6, 7 can be repaired or replaced before major damage occurs. Furthermore, this invention requires only one test.

[0074] The opening times of main valves 6, 6a, and 6b are shorter than those of secondary valves 7, 7a, and 7b. Secondary valves 7, 7a, and 7b open before main valves 6, 6a, and 6b open; therefore, they are also referred to as window valves because they provide a fluid communication window with main valves 6, 6a, and 6b. Thus, secondary valves 7, 7a, and 7b open when main valves 6, 6a, and 6b are closed, and close when main valves 6, 6a, and 6b are closed. Main valves 6, 6a, and 6b open and / or close when secondary valves 7, 7a, and 7b open.

[0075] First pressure sensors 8 and 8a measure real-time and / or continuous first pressure signals 9 and 9a, and second pressure sensors 8 and 8b measure real-time and / or continuous second pressure signals 9 and 9b. Thus, although still very small, leaks or malfunctions can be detected at any time during the opening and closing sequence of valves 6, 6a, 6b, 7, 7a, 7b, because pressure signals 9, 9a, 9b can be compared at any given time during that sequence.

[0076] exist Figure 2 In this internal combustion engine 1, there are a first cylinder 2 and a second cylinder 3. The fuel supply system 4 includes first cylinder fuel supply passages 5 and 5a for supplying fuel to the first cylinder 2 and second cylinder fuel supply passages 5 and 5b for supplying fuel to the second cylinder 3. The first cylinder fuel supply passages 5 and 5a include first master valves 6 and 6a, first pressure sensors 8 and 8a, and first stage valves 7 and 7a; the second cylinder fuel supply passages 5 and 5b include second master valves 6 and 6b, second pressure sensors 8 and 8b, and second stage valves 7 and 7b. The first cylinder fuel supply passages 5 and 5a are fluidly connected to the first cylinder 2 for injecting fuel into the first cylinder 2, and the second cylinder fuel supply passages 5 and 5b are fluidly connected to the second cylinder 3 for injecting fuel into the second cylinder 3. Figure 2 In this process, the comparison unit 10 compares the first pressure signals 9, 9a from the first pressure sensors 8, 8a with the second pressure signals 9, 9b from the second pressure sensors 8, 8b to detect any differences between the first pressure signals 9, 9a and the second pressure signals 9, 9b. The first pressure signals 9, 9a correspond to the pressure measured in the first cylinder fuel supply passages 5, 5a that supply fuel to the first cylinder 2, while the second pressure signals 9, 9b correspond to the pressure measured in the second cylinder fuel supply passages 5, 5b that supply fuel to the second cylinder 3. Because fuel is injected into the first cylinder 2 before being injected into the second cylinder 3, the peak values ​​of the first pressure signals 9, 9a will be shifted relative to the peak values ​​of the second pressure signals 9, 9b in a timely manner.

[0077] exist Figure 1-3In this system, the fuel supply system 4 also includes a main supply channel 12, which is fluidly connected to the first cylinder fuel supply channels 5, 5a and the second cylinder fuel supply channels 5, 5b for supplying fuel from the pump 11. Therefore, the main supply channel 12 is positioned upstream of the first cylinder fuel supply channels 5, 5a and the second cylinder fuel supply channels 5, 5b. The pressure of the fuel entering the first cylinder fuel supply channels 5, 5a may differ slightly from the pressure of the fuel entering the second cylinder fuel supply channels 5, 5b, but the correlation between the first pressure signals 9, 9a and the second pressure signals 9, 9b is the same because the pressure difference will be significantly the same. Comparing the first pressure signals 9, 9a and the second pressure signals 9, 9b will still provide an early warning of any leak or malfunction of one of the valves 6, 6a, 6b, 7, 7a, 7b, and leak or malfunction detection is therefore independent of such pressure changes in the main supply channel 12.

[0078] Figure 3 The internal combustion engine 1 includes four cylinders: a first cylinder 2, a second cylinder 3, a third cylinder 14, and a fourth cylinder 15. Both the third cylinder 14 and the fourth cylinder 15 are supplied with fuel via two fuel supply channels 5, 5a, and 5b through a first portion 12a and a second portion 12b of a main supply channel 12. Each of the two fuel supply channels 5, 5a, and 5b has a pressure sensor 8, a secondary valve 7, and a main valve 6. The fuel supply system 4 includes a pump 11 that supplies fuel to all four cylinders 2, 3, 14, and 15 via fuel supply channels 5, 5a, and 5b.

[0079] like Figure 4 As shown, the first pressure signals 9 and 9a form the first mode P1, and the second pressure signals 9 and 9b form the second mode P2. Comparing the first mode P1 and the second mode P2 will generate a correlation. The comparison unit 10 compares the first mode P1 with the second mode P2 to detect the correlation; if the correlation is within a predetermined range, valves 6, 6a, 6b, 7, 7a, and 7b operate as planned; however, if the correlation is outside the predetermined range, one of valves 6, 6a, 6b, 7, 7a, and 7b may have a leak or malfunction. Figure 4 In the second pressure signals 9 and 9b, the correlation is relatively small. When the first pressure signals 9 and 9a and the second pressure signals 9 and 9b are continuously measured and compared, modes P1 and P2 are the same, and the correlation remains the same as long as valves 6, 6a, 6b, 7, 7a, and 7b operate as planned without any leaks or malfunctions. Figure 4As shown. If one of the first main valves 6, 6a or the first secondary valves 7, 7a fails to operate as planned, the first pressure signals 9, 9a will change the first mode P1, and the correlation will be outside the predetermined range. Since the first mode P1 may change due to pressure fluctuations elsewhere in the fuel supply system 4, such fluctuations will also affect the second mode P2; when comparing the first pressure signals 9, 9a and the second pressure signals 9, 9b, if the change is due to changes elsewhere in the fuel supply system 4 and not due to a failure of one of the main valves or secondary valves 6, 6a, 6b, 7, 7a, 7b, the correlation will be the same and within the predetermined range. Therefore, by comparing the first pressure signals 9, 9a and the second pressure signals 9, 9b, small changes caused by leaks or failures of the main valves 6, 6a, 6b or the secondary valves 7, 7a, 7b can be detected as early as possible, because the predetermined range of the correlation can be set very narrow, since other system changes are leveled out when comparing the continuously measured first and second pressures, i.e., when comparing the first pressure signals 9, 9a and the second pressure signals 9, 9b. If the first pressure signals 9, 9a are compared with another pressure signal, the system change may only affect one of the pressure signals, and the correlation interval must then be set wider, because otherwise the operation will stop too frequently, and small leaks or faults will not be detected as early as when comparing the first pressure signals 9, 9a and the second pressure signals 9, 9b.

[0080] exist Figure 4 In the diagram, the first pressure signals 9 and 9a have a predetermined number of data points within a predetermined time period during continuous real-time measurement. The second pressure signals 9 and 9b are shown as dashed lines, but they also have a predetermined number of data points within a predetermined time period during continuous real-time measurement. The predetermined time period can be the period from when the secondary valves 7, 7a, and 7b are closed. Figure 4 (Indicated by arrow C2) until the next closure of secondary valves 7, 7a, and 7b, as shown. Figure 4 As shown, or any other time period from one operating position to the reappearance of the same operating position, that is, a sequence including one or all operating positions of valves 6, 6a, 6b, 7, 7a, 7b, meaning all operating positions of main valves 6, 6a, 6b open and closed, and secondary valves 7, 7a, 7b open and closed, and these positions are counted. Arrow C1 indicates the closure of main valves 6, 6a, 6b, arrow O1 indicates the opening of main valves 6, 6a, 6b, arrow O2 indicates the opening of secondary valves 7, 7a, 7b, and arrow C2 indicates the closure of secondary valves 7, 7a, 7b. The predetermined time period can also be a shorter interval than the sequence including one or all operating positions of valves 6, 6a, 6b, 7, 7a, 7b, for example, from the closure of main valves 6, 6a, 6b as shown by arrow C1 to the closure of secondary valves 7, 7a, 7b as shown by arrow C2.

[0081] Two similar valves, 6, 6a, 6b, 7, 7a, 7b, will never operate in exactly the same way, and when setting up the fuel supply system 4, cylinders 2, 3, 14, 15, etc., the fuel supply channels 5, 5a, 5b will change from one to the other. By measuring and comparing the pressure in the two similar channels 5, 5a, 5b, leaks or malfunctions in the main valve or secondary valves 6, 6a, 6b, 7, 7a, 7b can be detected as early as possible. The changes in pressure signals 9, 9a, and 9b may be due to pressure changes caused by the internal combustion engine 1 or the valves 6, 6a, 6b, 7, 7a, and 7b themselves. However, once the internal combustion engine 1 and valves 6, 6a, 6b, 7, 7a, and 7b are installed and operating as expected, the pressure signals 9, 9a, and 9b of one fuel supply passage 5, 5a, and 5b with main valves 6, 6a, and 6b and secondary valves 7, 7a, and 7b will change in the same way as the other fuel supply passage 5, 5a, and 5b with both main valves 6, 6a, and 6b and secondary valves 7, 7a, and 7b.

[0082] As described above, fuel is first injected into the first cylinder 2 and then into the second cylinder 3. Therefore, the peak values ​​of the first pressure signals 9, 9a will shift relative to the peak values ​​of the second pressure signals 9, 9b. Thus, by measuring and comparing the pressures in two similar channels 5, 5a, 5b, one supplying fuel to the first cylinder 2 and the other supplying fuel to the second cylinder 3, the first pressure signals 9, 9a will shift relative to the second pressure signals 9, 9b. When these pressure signals 9, 9a, 9b are compared, the first pressure signals 9, 9a shift in time to match the pattern / sequence of the second pressure signals 9, 9b, thereby aligning the opening and closing of valves 6, 6a, 6b, 7, 7a, 7b.

[0083] The comparison unit 10 may be a central processing unit (CPU), a control unit, a comparison unit, or a hardware- or software-based comparator. The comparison unit 10 may use pattern recognition software.

[0084] The fuel supplied via the main supply channel 12 can be propane, ethylene, ethane, butane, methanol, methane, ethanol, ammonia, propylene, butene, isobutane, n-butane, hydrogen, kerosene, nitromethane, liquefied petroleum gas, bioethanol, or biodiesel. Therefore, the fuel can be the sole fuel supplied to cylinders 2, 3, 14, and 15, or it can be a secondary fuel, where the primary fuel is diesel, gasoline, or petroleum. The fuel can be liquid or gaseous. Therefore, the sulfur content of the primary fuel can be at least 0.05%.

[0085] The present invention also relates to a leakage detection method for detecting leakage in valves 6, 6a, 6b, 7, 7a, 7b in a fuel supply system 4 of at least a first cylinder 2 and a second cylinder 3 of an internal combustion engine. In this method, during a first time period, a first pressure signal 9, 9a is measured by a first pressure sensor 8, 8a between a first main valve 6, 6a and a first stage valve 7, 7a on the fuel supply passages 5, 5a of the first cylinder of the fuel supply system 4. During a first time period or a second time period, a second pressure signal 9, 9b is measured by a second pressure sensor 8, 8b between a second main valve 6, 6b and a second stage valve 7, 7b on the fuel supply passages 5, 5b of the second cylinder of the fuel supply system 4. The first pressure signal 9, 9a is compared with the second pressure signal 9, 9b to detect leakage in one of valves 6, 6a, 6b, 7, 7a, 7b.

[0086] The present invention also relates to a computer program product comprising a computer-readable medium storing computer program code, wherein, when loaded, the computer program product causes a computer to execute the leak detection method.

[0087] Although the invention has been described above in conjunction with preferred embodiments thereof, it will be apparent to those skilled in the art that various modifications may be conceived without departing from the invention as defined by the following claims.

Claims

1. An internal combustion engine (1) for ship propulsion, the internal combustion engine having at least one cylinder (2), and comprising: - Fuel supply system (4), which includes: - A first cylinder fuel supply passage (5, 5a), comprising a first main valve (6, 6a) and a first stage valve (7, 7a) disposed upstream of the first main valve (6, 6a), and - The second cylinder fuel supply passage (5, 5b) includes a second main valve (6, 6b) and a secondary stage valve (7, 7b) disposed upstream of the second main valve (6, 6b). Specifically, a first pressure sensor (8, 8a) providing a first pressure signal (9, 9a) is arranged between the first main valve (6, 6a) and the first stage valve (7, 7a), and a second pressure sensor (8, 8b) providing a second pressure signal (9, 9b) is arranged between the second main valve (6, 6b) and the second stage valve (7, 7b). The internal combustion engine (1) is characterized in that it further includes a comparison unit (10) which compares the first pressure signal (9, 9a) with the second pressure signal (9, 9b) to detect the difference between the first pressure signal (9, 9a) and the second pressure signal (9, 9b).

2. The internal combustion engine (1) according to claim 1, wherein, The at least one cylinder is a first cylinder (2), and the internal combustion engine (1) also includes a second cylinder (3).

3. The internal combustion engine (1) according to claim 2, wherein, The first cylinder fuel supply passage (5, 5a) is fluidly connected to the first cylinder (2), and the second cylinder fuel supply passage (5, 5b) is fluidly connected to the first cylinder (2) or the second cylinder (3).

4. The internal combustion engine (1) according to any one of claims 1-3, wherein, The fuel supply system (4) includes a main supply channel (12) that is fluidly connected to the fuel supply channels (5, 5a) of the first cylinder and the fuel supply channels (5, 5b) of the second cylinder.

5. The internal combustion engine (1) according to any one of claims 1-3, wherein, The first pressure sensor (8, 8a) is configured to measure a real-time and / or continuous first pressure signal (9, 9a), and the second pressure sensor (8, 8b) is configured to measure a real-time and / or continuous second pressure signal (9, 9b).

6. The internal combustion engine (1) according to any one of claims 1-3, wherein, The fuel is propane, butane, methanol, methane, ethanol, ethane, ethylene, ammonia, propylene, butene, isobutane, n-butane, hydrogen, kerosene, nitromethane, liquefied petroleum gas, bioethanol, or biodiesel.

7. The internal combustion engine (1) according to any one of claims 1-3, wherein, The opening time of the first main valve (6, 6a) is shorter than the opening time of the first stage valve (7, 7a), and / or the opening time of the second main valve (6, 6b) is shorter than the opening time of the second stage valve (7, 7b).

8. The internal combustion engine (1) according to any one of claims 1-3, wherein, The primary stage valve (7, 7a) is configured to open before the first main valve (6, 6a) opens, and / or the secondary stage valve (7, 7b) is configured to open before the second main valve (6, 6b) opens.

9. The internal combustion engine (1) according to any one of claims 1-3, wherein, The first pressure signal (9, 9a) is configured to form a first mode (P1), and the second pressure signal (9, 9b) is configured to form a second mode (P2), wherein the comparison unit (10) is configured to compare the first mode (P1) with the second mode (P2) to detect correlation and verify whether the correlation is within a predetermined range.

10. A leakage detection method for detecting leakage in a valve in a fuel supply system (4), said fuel supply system (4) for supplying fuel to at least one cylinder (2) of an internal combustion engine (1) according to any one of claims 1-9, said method comprising: -A first pressure signal (9, 9a) is measured during a first time period by the first pressure sensor (8, 8a) between the first main valve (6, 6a) and the first stage valve (7, 7a) on the first cylinder fuel supply passage (5, 5a) of the fuel supply system (4). -The second pressure signal (9, 9b) is measured during the first or second time period by the second pressure sensor (8, 8b) between the second main valve (6, 6b) and the second stage valve (7, 7b) on the second cylinder fuel supply passage (5, 5b) of the fuel supply system (4), and - Compare the first pressure signal (9, 9a) with the second pressure signal (9, 9b) to detect leakage in one of the first main valve, the first stage valve, the second main valve, and the second stage valve.

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