EP4709978A1 - Pipe connection arrangement, fuel supply system, internal combustion engine and method of operating an internal combustion engine - Google Patents

Pipe connection arrangement, fuel supply system, internal combustion engine and method of operating an internal combustion engine

Info

Publication number
EP4709978A1
EP4709978A1 EP23723224.4A EP23723224A EP4709978A1 EP 4709978 A1 EP4709978 A1 EP 4709978A1 EP 23723224 A EP23723224 A EP 23723224A EP 4709978 A1 EP4709978 A1 EP 4709978A1
Authority
EP
European Patent Office
Prior art keywords
fuel
pipe
inert gas
connecting block
inlet
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP23723224.4A
Other languages
German (de)
French (fr)
Inventor
Janne PELTTARI
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Wartsila Finland Oy
Original Assignee
Wartsila Finland Oy
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Wartsila Finland Oy filed Critical Wartsila Finland Oy
Publication of EP4709978A1 publication Critical patent/EP4709978A1/en
Pending legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M37/00—Apparatus or systems for feeding liquid fuel from storage containers to carburettors or fuel-injection apparatus; Arrangements for purifying liquid fuel specially adapted for, or arranged on, internal-combustion engines
    • F02M37/0011—Constructional details; Manufacturing or assembly of elements of fuel systems; Materials therefor
    • F02M37/0017—Constructional details; Manufacturing or assembly of elements of fuel systems; Materials therefor related to fuel pipes or their connections, e.g. joints or sealings
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M21/00—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form
    • F02M21/02—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form for gaseous fuels
    • F02M21/0218—Details on the gaseous fuel supply system, e.g. tanks, valves, pipes, pumps, rails, injectors or mixers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M21/00—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form
    • F02M21/02—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form for gaseous fuels
    • F02M21/0218—Details on the gaseous fuel supply system, e.g. tanks, valves, pipes, pumps, rails, injectors or mixers
    • F02M21/0293—Safety devices; Fail-safe measures
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M37/00—Apparatus or systems for feeding liquid fuel from storage containers to carburettors or fuel-injection apparatus; Arrangements for purifying liquid fuel specially adapted for, or arranged on, internal-combustion engines
    • F02M37/0047—Layout or arrangement of systems for feeding fuel
    • F02M37/0064—Layout or arrangement of systems for feeding fuel for engines being fed with multiple fuels or fuels having special properties, e.g. bio-fuels; varying the fuel composition
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M55/00—Fuel-injection apparatus characterised by their fuel conduits or their venting means; Arrangements of conduits between fuel tank and pump F02M37/00
    • F02M55/002—Arrangement of leakage or drain conduits in or from injectors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M65/00—Testing fuel-injection apparatus, e.g. testing injection timing ; Cleaning of fuel-injection apparatus
    • F02M65/006—Measuring or detecting fuel leakage of fuel injection apparatus
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
    • F16L39/00—Joints or fittings for double-walled or multi-channel pipes or pipe assemblies
    • F16L39/005—Joints or fittings for double-walled or multi-channel pipes or pipe assemblies for concentric pipes
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
    • F16L39/00—Joints or fittings for double-walled or multi-channel pipes or pipe assemblies
    • F16L39/02—Joints or fittings for double-walled or multi-channel pipes or pipe assemblies for hoses
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
    • F16L39/00—Joints or fittings for double-walled or multi-channel pipes or pipe assemblies
    • F16L39/04—Joints or fittings for double-walled or multi-channel pipes or pipe assemblies allowing adjustment or movement

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Fuel-Injection Apparatus (AREA)
  • Pipeline Systems (AREA)

Abstract

The pipe connection arrangement for a fuel supply system of an internal combustion engine (1) comprises a first connecting block (120) attachable to the engine (1), a second connecting block (140) to be arranged at a distance from the engine (1), a double-walled connecting pipe (170) having a first end connectable to the first connecting block (120) and a second end connectable to the second connecting block (140), and an inert gas pipe (174) having a first end connectable to an inert gas outlet (125) or inlet (124) of the first connecting block (120) and a second end connectable to an inert gas inlet (144) or outlet (145) of the second connecting block (140), the second connecting block (140) comprising a leakage channel (149) having an inlet (147) arrangeable in fluid communication with a leakage space (173) of the connecting pipe (170), the leakage channel (149) comprising a closure element (150) being configured to move from a closed position to an open position when the pressure on the inlet side of the closure element (150) exceeds a predetermined threshold.

Description

Pipe connection arrangement, fuel supply system, internal combustion engine and method of operating an internal combustion engine
Technical field of the invention
The present invention concerns a pipe connection arrangement for a fuel supply system of an internal combustion engine, as defined in claim 1 . The invention also concerns a fuel supply system, an internal combustion engine and a method of operating an internal combustion engine.
Background of the invention
There is an increasing need for large internal combustion engines, such as ship and power plant engines, that can be operated using other types of fuel than conventional liquid fuels, such as light fuel oil or heavy fuel oil. Alternative fuels can be either liquid fuels, such as methanol or ammonia, or gaseous fuels, such as natural gas or hydrogen.
The use of alternative fuels helps reducing carbon dioxide and other emissions of the engines. However, the use of alternative fuels also poses many challenges. For instance, leakages of gaseous fuels pose a much more serious safety risk than leakages of liquid fuels with high flash point. Also, some fuels, such as methanol, can be more toxic than conventional fuels, such as light fuel oil.
In many cases, the use of alternative fuels causes a need for extra safety measures. A common safety measure to address both the risk of fires and poisoning is to use double-walled pipes for conveying fuel. A double-walled pipe comprises an inner pipe for conveying the fuel and an outer pipe arranged coaxially around the inner pipe to form an annular leakage space between the two pipes. The leakage space collects the fuel possibly leaking from the inner pipe and allows both detecting leakages and conveying the leaking fuel to a safe place, such as a tank or outdoors. In case of a leakage, the inner pipe and the leakage space can be purged using an inert gas, such as nitrogen.
The double-walled pipes of fuel supply systems are typically steel pipes. However, due to the vibrations of the engine, all the connecting pipes cannot be constructed as rigid pipes, but the fuel supply system needs to comprise a flexible portion allowing movements of the engine. The requirement of flexibility limits the availability of suitable materials.
Summary of the invention
An object of the invention is to provide a pipe connection arrangement for a fuel supply system of an internal combustion engine. Other objects of the invention are to provide an improved fuel supply system for an internal combustion engine, an improved internal combustion engine, and a method of operating an internal combustion engine.
The pipe connection arrangement according to the invention comprises
- a first connecting block configured to be rigidly attached to the engine, the first connecting block comprising a fuel inlet for receiving fuel, a fuel outlet, a fuel channel establishing fluid communication between said fuel inlet and fuel outlet, an inert gas inlet, an inert gas outlet, and an inert gas channel establishing fluid communication between said inert gas inlet and inert gas outlet,
- a second connecting block configured to be arranged at a distance from the engine, the second connecting block comprising a fuel inlet for receiving fuel, a fuel outlet, a fuel channel establishing fluid communication between said fuel inlet and fuel outlet, an inert gas inlet for receiving inert gas, an inert gas outlet, and an inert gas channel establishing fluid communication between said inert gas inlet and inert gas outlet,
- a double-walled connecting pipe having a first end and a second end, the first end being connectable to the first connecting block and the second end being connectable to the second connecting block, the connecting pipe comprising an inner pipe for conveying liquid fuel to the engine and an outer pipe arranged around the inner pipe such that a leakage space is formed between said inner pipe and outer pipe, wherein at the first end of the connecting pipe the inner pipe is connectable to the fuel inlet of the first connecting block and at the second end of the connecting pipe the inner pipe is connectable to the fuel outlet of the second connecting block, and
- an inert gas pipe having a first end and a second end, the first end being connectable to the inert gas outlet or inlet of the first connecting block and the second end being connectable to the inert gas inlet or outlet of the second connecting block.
The second connecting block further comprises a leakage channel having an inlet and an outlet, the inlet being configured to be arranged in fluid communication with the leakage space of the double-walled connecting pipe, the leakage channel comprising a closure element having a closed position, in which flow between said inlet and outlet is prevented, and an open position, in which flow between said inlet and outlet is allowed, the closure element being configured to move from the closed position to the open position when the pressure on the inlet side of the closure element exceeds a predetermined threshold.
The pipe connection arrangement according to the invention can be used in a fuel supply system, where inert atmosphere is maintained in the leakage spaces of double-walled fuel supply pipes. The double-walled connecting pipe can be a flexible pipe. By means of the inert gas pipe, inert gas can be supplied from one of the connecting blocks to the other connecting block while keeping the leakage space of the double-walled connecting pipe free of the inert gas during normal operation of the engine. The double-walled connecting pipe is thus not exposed to the inert gas, which allows more freedom in the selection of the materials of the outer surface of the inner pipe of the connecting pipe and the inner surface of the outer pipe of the connecting pipe and increases the lifetime of the connecting pipe. In case of a leakage of the connecting pipe, the leaking fuel can be discharged via the leakage channel of the connecting block and the leakage space can be purged by the inert gas.
According to an embodiment of the invention, the second connecting block is configured such that an inner pipe of a double-walled fuel supply pipe can be connected to the fuel inlet of the second connecting block and a leakage space formed between the inner pipe and an outer pipe of said fuel supply pipe can be connected to the inert gas outlet or inlet of the second connecting block, and the outlet of the leakage channel is arranged such that the leakage channel is in fluid communication with the leakage space of the fuel supply pipe in a mounted state of the fuel supply pipe. The leakage space of the fuel supply pipe can thus be used for receiving leaking fuel from the leakage space of the connecting pipe and for conveying inert gas to or from the second connecting block.
According to an embodiment of the invention, the second connecting block comprises a leak indicator connected to the leakage channel. This allows easy detection of leakages of the connecting pipe.
According to an embodiment of the invention, the first connecting block further comprises a second fuel inlet, a second fuel outlet, a second fuel channel establishing fluid communication between said second fuel inlet and second fuel outlet, a second inert gas inlet, a second inert gas outlet, a second inert gas channel establishing fluid communication between said second inert gas inlet and inert gas outlet, and the second connecting block comprises a second fuel inlet, a second fuel outlet, a second fuel channel establishing fluid communication between said second fuel inlet and second fuel outlet, a second inert gas inlet, a second inert gas outlet, and a second inert gas channel establishing fluid communication between said second inert gas inlet and inert gas outlet. The pipe connection arrangement further comprises
- a second double-walled connecting pipe having a first end and a second end, the first end being connectable to the first connecting block and the second end being connectable to the second connecting block, the second connecting pipe comprising an inner pipe for conveying liquid fuel from the engine and an outer pipe arranged around the inner pipe such that a leakage space is formed between the inner pipe and the outer pipe, wherein at the first end of the second connecting pipe the inner pipe is connectable to the second fuel outlet of the first connecting block and at the second end of the second connecting pipe the inner pipe is connectable to the second fuel inlet of the second connecting block, and
- a second inert gas pipe having a first end and a second end, the first end being connectable to the second inert gas inlet or outlet of the first connecting block and the second end being connectable to the second inert gas outlet or inlet of the second connecting block.
The second connecting block further comprises a second leakage channel having an inlet and an outlet, the inlet being configured to be arranged in fluid communication with the leakage space of the second connecting pipe, the second leakage channel comprising a closure element having a closed position, in which flow between said inlet and outlet is prevented, and an open position, in which flow between said inlet and outlet is allowed, the closure element being configured to move from the closed position to the open position when the pressure on the inlet side of the closure element exceeds a predetermined threshold.
The pipe connection arrangement can thus be configured to convey also fuel overflow from the engine and the second connecting pipe can be provided in a similar way as the first connecting pipe with a leakage space that is during normal operation of the engine free of inert gas but collects possibly leaking fuel.
According to an embodiment of the invention, the second connecting block is configured such that an inner pipe of a double-walled fuel return pipe can be connected to the second fuel outlet of the second connecting block and a leakage space formed between the inner pipe and an outer pipe of said fuel return pipe can be connected to the second inert gas inlet or outlet of the second connecting block, and the outlet of the second leakage channel is arranged such that the second leakage channel is in fluid communication with the leakage space of the fuel return pipe in a mounted state of the fuel return pipe.
The leakage space of the fuel return pipe can thus be used for receiving leaking fuel from the leakage space of the connecting pipe and for conveying inert gas to or from the second connecting block.
According to an embodiment of the invention, the second connecting block comprises a leak indicator connected to the second leakage channel. This allows easy detection of leakages of the second connecting pipe.
The fuel supply system according to the invention comprises a pipe connection arrangement defined above and a fuel supply pipe connected to the second connecting block.
An internal combustion engine according to the invention comprises a fuel supply system defined above.
The method according to the invention for operating an internal combustion engine defined above comprises the steps of - filling leakage spaces of the fuel supply system with inert gas, apart from the leakage spaces between the second connecting block and the first connecting block to create an inert atmosphere into the filled leakage spaces,
- supplying fuel to the engine via said fuel supply pipe, and
- maintaining the inert atmosphere in the leakage spaces while the engine is operated using the fuel supplied via said fuel supply pipe.
According to an embodiment of the invention, leakages into the leakage space of the connecting pipe are monitored, and in case a leakage is detected, the leakage space is purged by introducing inert gas into the leakage space.
Brief description of the drawings
Embodiments of the invention are described below in more detail with reference to the accompanying drawings, in which
Fig. 1 shows schematically a fuel supply system of an internal combustion engine,
Fig. 2 shows a perspective view of a pipe connection arrangement according to an embodiment of the invention,
Fig. 3 shows schematically a pipe connection arrangement according to an embodiment of the invention,
Fig. 4 shows as a flowchart the method according to the invention,
Fig. 5 shows a partial view of the pipe connection arrangement of figure 2,
Fig. 6 shows a partial cross-sectional view of the pipe connection arrangement of figure 2,
Fig. 7 shows a cross-sectional view of a connecting block, and
Fig. 8 shows another cross-sectional view of a connecting block.
Detailed description of embodiments of the invention
Figure 1 shows schematically a fuel supply system according to an embodiment of the invention. The fuel supply system supplies liquid fuel to an internal combustion engine 1 . The engine 1 is a piston engine. The engine 1 is a large piston engine, such as a main or an auxiliary engine of a ship or a power plant engine. The cylinder diameter of the engine is at least 150 mm and/or the rated power of the engine is at least 500 kW.
The fuel supply system of figure 1 supplies to the engine 1 first, liquid fuel. The first fuel can be, for instance, methanol. However, the first fuel could also be some other fuel. The first fuel can be, in particular, highly toxic and/or highly flammable, thus requiring specific protective measures for preventing the persons operating the engine 1 from being exposed to the fuel and/or for reducing the risk of fires.
The engine 1 can be provided with two or more separate or partly separate fuel supply systems. For instance, the engine 1 can be operable using second fuel and the engine 1 could be provided with a separate fuel supply system for supplying the second fuel to the engine 1 . The second fuel could be liquid fuel, such as light fuel oil, or gaseous fuel, such as natural gas. The engine 1 could also be operable using mixtures of different fuels or using one fuel as main fuel and another fuel as pilot fuel for igniting the main fuel.
The fuel supply system comprises a double-walled fuel line 2 for supplying fuel to the engine 1 . The fuel line 2 comprises an inner pipe 3 that is configured to convey the first fuel and an outer pipe 4 arranged around the inner pipe 3 such that an annular leakage space 5 is formed between the inner pipe 3 and the outer pipe 4. The annular leakage space 5 does not need to be continuous but it can be divided into two or more sections. The fuel supply system comprises at least one fuel pump 19 for pressurizing the first fuel.
The fuel supply system further comprises leak detection means 6, 7, 8, 9, 14, 15, 16 for detecting a leakage of the first fuel into the leakage space 5, means 33, 43, 53 for supplying inert gas into said leakage space 5 when a leakage into the leakage space 5 is detected to purge the leakage space 5, and means 31 , 32, 41 , 42, 51 , 52 for supplying inert gas into the leakage space 5 for maintaining an inert atmosphere within the leakage space 5 when the engine 1 is operated using the first fuel.
In the fuel supply system according to the invention, inert gas is thus used for two purposes: during operation of the engine 1 using the first fuel, the leakage space 5 is kept filled with the inert gas. The inert atmosphere in the leakage space 5 effectively reduces the risk of fires if fuel leaks from the inner pipe 3 into the leakage space 5. In case of a leakage, the inert gas can be used for purging the leakage space 5 to remove the leaked fuel from the leakage space 5. The inert gas can be, for instance, nitrogen.
The leak detection means can comprise one or more pressure sensors 14, 15, 16 and/or one or more level sensors 6, 7, 8, 9. The level sensors 6, 7, 8, 9 can detect even small leakages of liquid fuel, but need to be positioned such that the leaking fuel reaches at least one of the level sensors. Pressure sensors 14, 15, 16 can be positioned more freely, but do not necessarily detect as small leakages as the level sensors 6, 7, 8, 9. On the other hand, the pressure sensors 14, 15, 16 can also be configured to detect leakages from the leakage space 5.
The leakage space 5 can be divided into two or more separate portions 5A, 5B, 5C, 5D such that leakage into one of the portions 5A, 5B, 5C, 5D can be detected independently of the other portions. This allows detecting where the fuel supply system is leaking. Also, in case of a leakage, it is not necessary to purge the whole leakage space 5 but it is sufficient to purge the affected portions of the leakage space 5.
In the embodiment of figure 1 , different functionalities of the fuel supply system are arranged in a leak unit 20. This provides a convenient way for filling the leakage space 5 with inert gas, monitoring leakages and purging the leakage space 5. However, the leak unit 20 is not necessary, but the fuel supply system could be implemented without the leak unit 20.
The leak unit 20 comprises the leak detection means 6, 7, 8, 9, 14, 15, 16 for detecting a leakage into the leakage space 5. The fuel line 2 comprises a first fuel supply portion 2A extending from the fuel pump 19 to the leak unit 20, a second fuel supply portion 2B extending from the leak unit 20 to the engine 1 , a first overflow portion 2C extending from the engine 1 to the leak unit 20, and a second overflow portion 2D extending from the leak unit 20 downstream. The leak unit 20 divides the leakage space 5 into the two or more separate portions 5A, 5B, 5C, 5D. The first fuel is supplied via the first and second fuel supply portions 2A, 2B to the engine 1 . Excess fuel from the engine 1 flows via the overflow portions 2C, 2D to an overflow tank.
In the embodiment of the figures, the leakage space 5 comprises four portions 5A, 5B, 5C, 5D. The leakage space portions 5B, 5C of the second fuel supply portion 2B and the first overflow portion 2C are in fluid communication with each other and thus not completely separated from each other. The fuel supply system is provided with a first pressure sensor 14, second pressure sensor 15 and third pressure sensor 16, which function as leak detection means. The first pressure sensor 14 is configured to monitor pressure in the leakage space portion 5A of the first fuel supply portion 2A, the second pressure sensor 15 is configured to monitor pressure in the leakage space portion 5D of the second overflow portion 2D and the third pressure sensor 16 is configured to monitor pressure in the leakage space portions 5B, 5C of the second fuel supply portion 2B and the first overflow portion 2C.
The leak unit 20 further comprises leak detection spaces 10, 11 , 12, 13 arranged in fluid communication with each leakage space portion 5A, 5B, 5C, 5D of the leakage space 5 and a level sensor 6, 7, 8, 9 arranged to detect presence of liquid in each of the leak detection spaces 10, 11 , 12, 13. The leak unit 20 is arranged such that it forms the lowermost part of the fuel supply system and the fuel leaking into the leakage space 5 thus flows to the leak unit 20 by gravity.
The leak unit 20 further comprises outlets and drain valves for draining each of the leak detection spaces 10, 11 , 12, 13.
For filling the leakage space 5 with the inert gas, the leakage space 5 is connected to an inert gas source 48. The inert gas can be stored in a tank at a pressure that is at least as high as the pressure needed for purging the leakage space 5. Alternatively, a pump can be arranged between the inert gas tank and the leakage space 5 to raise the pressure of the inert gas. The pressure used for purging the leakage space 5 can be, for instance, in the range of 600-1200 kPa.
Each separate portion of the leakage space 5 is connected to the inert gas source 48 via a filling valve 31 , 41 , 51 . The filling valves are controllable valves. In the embodiment of the figures, the fuel supply system comprises a first filling valve 31 for controlling the supply of inert gas into the leakage space portion 5A of the first fuel supply portion 2A, a second filling valve 41 for controlling the supply of inert gas into the leakage space portion 5D of the second overflow portion 2D, and a third filling valve 51 for controlling the supply of inert gas into the leakage space portions 5B, 5C of the second fuel supply portion 2B and the first overflow portion 2C. Each inert gas line supplying inert gas into the leakage space 5 is further provided with a pressure reduction valve 32, 42, 52 for lowering the pressure of the inert gas to the desired pressure level. The pressure of the inert gas supplied into the leakage space 5 for maintaining the inert atmosphere could be, for instance, in the range of 150-400 kPa.
For purging the leakage space 5, the fuel supply system is provided with a purging valve 33, 43, 53 for each separate portion of the leakage space for supplying the inert gas into the respective portion 5A, 5B, 5C, 5D at a higher pressure. In the embodiment of the figures, the fuel supply system thus comprises a first purging valve 33, a second purging valve 43, and a third purging valve 53. Via the purging valves 33, 43, 53, the inert gas can be supplied into the leakage space 5 at a higher pressure than via the filling valves 31 , 41 , 51 .
The same valves could be used both as the purging valves and the filling valves if the pressure of the inert gas can be regulated according to the need.
For preventing the vibrations of the engine 1 from being transmitted to all components of the fuel supply system, the fuel supply system is provided with a flexible portion. The flexible portion of the fuel supply system is arranged between a first connecting block 120 and a second connecting block 140. The first connecting block 120 is rigidly attached to the engine 1 and the second connecting block 140 is arranged at a distance from the engine 1 .
The first connecting block 120 comprises a first fuel inlet 121 for receiving fuel, a first fuel outlet 122, a first fuel channel 123 establishing fluid communication between the first fuel inlet 121 and the first fuel outlet 122, a first inert gas inlet 124, a first inert gas outlet 125, and a first inert gas channel 126 establishing fluid communication between the first inert gas inlet 124 and the first inert gas outlet 125. The second connecting block 140 comprises a first fuel inlet 141 for receiving fuel, a first fuel outlet 142, a first fuel channel 143 establishing fluid communication between the first fuel inlet 141 and the first fuel outlet 142, a first inert gas inlet 144 for receiving inert gas, a first inert gas outlet 145, and a first inert gas channel 146 establishing fluid communication between the first inert gas inlet 144 and the first inert gas outlet 145.
The fuel supply system further comprises a first double-walled connecting pipe
170 having a first end and a second end, the first end being connectable to the first connecting block 120 and the second end being connectable to the second connecting block 140, the first connecting pipe 170 comprising an inner pipe
171 for conveying liquid fuel to the engine 1 and an outer pipe 172 arranged around the inner pipe 171 such that a leakage space 173 is formed between the inner pipe 171 and the outer pipe 172. The first end of the inner pipe 171 of the first connecting pipe 170 is connected to the first fuel inlet 121 of the first connecting block 120 and the second end of the inner pipe 171 of the first connecting pipe 170 is connected to the first fuel outlet 142 of the second connecting block 140. The inner pipe 171 and the outer pipe 172 of the first connecting pipe 170 are flexible. The first connecting pipe 170 thus allows mutual movements of the first connecting block 120 and the second connecting block 140. This ensures that vibrations of the engine 1 do not cause leakages in the fuel supply system.
The fuel supply system further comprises a first inert gas pipe 174 having a first end and a second end, the first end being connected to the first inert gas outlet 125 of the first connecting block 120 and the second end being connectable to the first inert gas inlet 144 of the second connecting block 140. Also the first inert gas pipe 174 is flexible.
The second connecting block 140 further comprises a first leakage channel 149 having an inlet 147 and an outlet 148. The inlet 147 is arranged in fluid communication with the leakage space 173 of the first double-walled connecting pipe 170. The first leakage channel 149 comprises a closure element 150 having a closed position, in which flow between the inlet 147 and the outlet 148 is prevented, and an open position, in which flow between the inlet 147 and the outlet 148 is allowed. The closure element 150 is configured to move from the closed position to the open position when the pressure on the inlet side of the closure element 150 exceeds a predetermined threshold. The opening pressure of the closure element 150 can be, for instance, in the range of 100-300 kPa. When the opening pressure of the closure element 150 has been exceeded and the closure element 150 has moved to the open position, it remains in the open position until being manually moved back to the closed position.
In the embodiment of the figures, an inner pipe 176 of a double-walled fuel supply pipe 175 is connected to the first fuel inlet 141 of the second connecting block 140 and a leakage space 178 formed between the inner pipe 176 and an outer pipe 177 of the fuel supply pipe 175 is connected to the first inert gas outlet 145 of the second connecting block 140. The outlet 148 of the first leakage channel 149 is arranged such that the first leakage channel 149 is in fluid communication with the leakage space 178 of the fuel supply pipe 175.
The second connecting block 140 further comprises a first leak indicator 161 connected to the first leakage channel 149. In the embodiment of the figures, the first leak indicator 161 is a pin that pops out when the pressure in the first leakage channel 149 exceeds a predetermined threshold. In the embodiment of the figures, the leak indicator 161 is connected to the closure element 150 of the first leakage channel 149 and a leakage is indicated when the closure element 150 moves to the open position.
In the embodiment of the figures, the first connecting block 120 further comprises a second fuel inlet 131 , a second fuel outlet 132, a second fuel channel 133 establishing fluid communication between the second fuel inlet 131 and second fuel outlet 132, a second inert gas inlet 134, a second inert gas outlet 135, and a second inert gas channel 136 establishing fluid communication between the second inert gas inlet 134 and the second inert gas outlet 135.
The second connecting block 140 comprises a second fuel inlet 151 , a second fuel outlet 152, a second fuel channel 153 establishing fluid communication between the second fuel inlet 151 and the second fuel outlet 152, a second inert gas inlet 154, a second inert gas outlet 155, and a second inert gas channel 156 establishing fluid communication between the second inert gas inlet 154 and the second inert gas outlet 155. The fuel supply system comprises a second double-walled connecting pipe 180 having a first end and a second end. The first end is connected to the first connecting block 120 and the second end is connected to the second connecting block 140. The second connecting pipe 180 comprises an inner pipe 181 for conveying liquid fuel from the engine 1 and an outer pipe 182 arranged around the inner pipe 181 such that a leakage space 183 is formed between the inner pipe 181 and the outer pipe 182. The first end of the inner pipe of the second connecting pipe 180 is connected to the second fuel outlet 132 of the first connecting block 120 and the second end of the inner pipe 181 of the second connecting pipe 180 is connected to the second fuel inlet 151 of the second connecting block 140.
The fuel supply system further comprises a second inert gas pipe 184 having a first end and a second end. The first end is connected to the second inert gas inlet 134 of the first connecting block 120 and the second end is connected to the second inert gas outlet 155 of the second connecting block 140. The second inert gas pipe 184 is a flexible pipe.
The second connecting block 140 further comprises a second leakage channel 159 having an inlet 157 and an outlet 158. The inlet 157 is arranged in fluid communication with the leakage space 183 of the second connecting pipe 180. The second leakage channel 159 comprises a closure element 160 having a closed position, in which flow between the inlet 157 and the outlet 158 is prevented, and an open position, in which flow between the inlet 157 and the outlet 158 is allowed. The closure element 160 is configured to move from the closed position to the open position when the pressure on the inlet side of the closure element 160 exceeds a predetermined threshold. The closure element 160 of the second leakage channel 159 functions in the same way as the closure element 150 of the first leakage channel 149.
An inner pipe 186 of a double-walled fuel return pipe 185 is connected to the second fuel outlet 152 of the second connecting block 140 and a leakage space 188 formed between the inner pipe 186 and an outer pipe 187 of the fuel return pipe 185 is connected to the second inert gas inlet 154 of the second connecting block 140. The outlet 158 of the second leakage channel 159 is arranged in fluid communication with the leakage space 188 of the fuel return pipe 185. The second connecting block 140 comprises a second leak indicator 162 connected to the second leakage channel 159. The second leak indicator 162 can be similar to the first leak indicator 161 .
The fuel supply pipe 175 and the first connecting pipe 170 form part of the second fuel supply portion 2B of the fuel line 2. The fuel return pipe 185 and the second connecting pipe 180 form part of the first overflow portion 2C of the fuel line 2.
The inert gas introduced into the leakage space 188 of the fuel return pipe 185 can flow via the second connecting block 140 into the second inert gas pipe 184 and further via the first connecting block 120 to the engine 1. From the engine 1 , the inert gas can flow to the first connecting block 120 and via the first inert gas pipe 174 to the second connecting block 140 and further into the leakage space 178 of the fuel supply pipe 175.
During normal operation of the engine 1 , there is no inert gas in the leakage spaces 173, 183 of the first connecting pipe 170 and the second connecting pipe 180. This allows making the outer surfaces of the inner pipes 171 , 181 of the first and second connecting pipes 170, 180 of a material that does not withstand long-term exposure to the inert gas.
In a first step 101 of the method according to the invention the leakage spaces of the double-walled pipes of the fuel supply system are filled with inert gas to create an inert atmosphere into the filled leakage spaces. However, the leakage spaces 173, 183 of the first and second connecting pipes 170, 180 between the first connecting block 120 and the second connecting block 140 are not filled with the inert gas. In a second step 102 of the method, fuel is supplied to the engine via the fuel line 2 of the fuel supply system. In a third step 103 of the method, inert atmosphere in the leakage spaces of the fuel supply system is maintained while the engine is operated using the fuel supplied via the fuel line 2.
In case there is a leakage from the fuel line 2 into the leakage space 173, 183 of one of the connecting pipes 170, 180, the pressure in the respective leakage space 173, 183 rises. When the opening pressure of the closure element 150, 160 of the leakage channel 149, 159 is exceeded, the closure element 150, 160 moves to the open position and the leaking fuel can flow into the leakage space 178, 188 of the fuel supply pipe 175 or the fuel return pipe 185 and further to the leak unit 20. The leak detection means of the leak unit 20 can detect the leakage. The leak is indicated also by the respective leak indicator 161 , 162 of the second connecting block 140. As the closure element 150, 160 moves to the open position, the inert gas in the leakage space 178, 188 of the fuel supply pipe 175 or the fuel return pipe 185 can flow into the leakage space 173, 183 of the respective connecting pipe 170, 180.
When a leakage has been detected, an alarm can be triggered and the engine 1 can be switched to use another fuel or shut down.
In case a leakage into the leakage spaces 173, 183 of the first and second connecting pipes 170, 180 is detected, the respective leakage space 173, 183 can be purged by introducing inert gas into the leakage space 173, 183 at a higher pressure than the pressure of the inert atmosphere maintained during normal operation of the engine 1. After purging of the system, the leakage spaces are emptied and the closure element 150, 160 can be moved back to the closed position.
In the embodiment of the figures, the inert gas is introduced into the leakage spaces between the leak unit 20 and the engine 1 via the leakage space 188 of the fuel return pipe 185. However, the inert gas could be supplied also via the leakage space 178 of the fuel supply pipe 175.
In the embodiment of the figures, the connecting pipes 170, 180 for both the fuel supply and fuel return are arranged between the first and the second connecting blocks 120, 140. However, instead of having common connecting blocks 120, 140 for the fuel supply and fuel return, the fuel supply system could be provided with separate connecting blocks for the fuel supply and fuel return.

Claims

Claims:
1 . A pipe connection arrangement for a fuel supply system of an internal combustion engine (1 ), the pipe connection arrangement comprising
- a first connecting block (120) configured to be rigidly attached to the engine (1 ), the first connecting block (120) comprising a fuel inlet (121 ) for receiving fuel, a fuel outlet (122), a fuel channel (123) establishing fluid communication between said fuel inlet (121 ) and fuel outlet (122), an inert gas inlet (124), an inert gas outlet (125), and an inert gas channel (126) establishing fluid communication between said inert gas inlet (124) and inert gas outlet (125),
- a second connecting block (140) configured to be arranged at a distance from the engine (1 ), the second connecting block (140) comprising a fuel inlet (141 ) for receiving fuel, a fuel outlet (142), a fuel channel (143) establishing fluid communication between said fuel inlet (141 ) and fuel outlet (142), an inert gas inlet (144) for receiving inert gas, an inert gas outlet (145), and an inert gas channel (146) establishing fluid communication between said inert gas inlet (144) and inert gas outlet (145),
- a double-walled connecting pipe (170) having a first end and a second end, the first end being connectable to the first connecting block (120) and the second end being connectable to the second connecting block (140), the connecting pipe (170) comprising an inner pipe
(171 ) for conveying liquid fuel to the engine (1 ) and an outer pipe
(172) arranged around the inner pipe (171 ) such that a leakage space (173) is formed between said inner pipe (171 ) and outer pipe (172), wherein at the first end of the connecting pipe (170) the inner pipe (171 ) is connectable to the fuel inlet (121 ) of the first connecting block (120) and at the second end of the connecting pipe (170) the inner pipe (171 ) is connectable to the fuel outlet (142) of the second connecting block (140), and
- an inert gas pipe (174) having a first end and a second end, the first end being connectable to the inert gas outlet (125) or inlet (124) of the first connecting block (120) and the second end being connectable to the inert gas inlet (144) or outlet (145) of the second connecting block (140), wherein the second connecting block (140) further comprises a leakage channel (149) having an inlet (147) and an outlet (148), the inlet (147) being configured to be arranged in fluid communication with the leakage space (173) of the double-walled connecting pipe (170), the leakage channel (149) comprising a closure element (150) having a closed position, in which flow between said inlet (147) and outlet (148) is prevented, and an open position, in which flow between said inlet (147) and outlet (148) is allowed, the closure element (150) being configured to move from the closed position to the open position when the pressure on the inlet side of the closure element (150) exceeds a predetermined threshold.
2. A pipe connection arrangement according to claim 1 , wherein the second connecting block (140) is configured such that an inner pipe (176) of a double-walled fuel supply pipe (175) can be connected to the fuel inlet (141 ) of the second connecting block (140) and a leakage space (178) formed between the inner pipe (176) and an outer pipe (177) of said fuel supply pipe (175) can be connected to the inert gas outlet (145) or inlet (144) of the second connecting block (140), and the outlet (148) of the leakage channel (149) is arranged such that the leakage channel (149) is in fluid communication with the leakage space (178) of the fuel supply pipe (175) in a mounted state of the fuel supply pipe (175).
3. A pipe connection arrangement according to claim 1 or 2, wherein the second connecting block (140) comprises a leak indicator (161 ) connected to the leakage channel (149).
4. A pipe connection arrangement according to any of claims 1-3, wherein the first connecting block (120) further comprises a second fuel inlet (131 ), a second fuel outlet (132), a second fuel channel (133) establishing fluid communication between said second fuel inlet (131 ) and second fuel outlet (132), a second inert gas inlet (134), a second inert gas outlet (135), a second inert gas channel (136) establishing fluid communication between said second inert gas inlet (134) and inert gas outlet (136), and the second connecting block (140) comprises a second fuel inlet (151 ), a second fuel outlet (152), a second fuel channel (153) establishing fluid communication between said second fuel inlet (151 ) and second fuel outlet (152), a second inert gas inlet (154), a second inert gas outlet (155), and a second inert gas channel (156) establishing fluid communication between said second inert gas inlet (154) and inert gas outlet (155), the pipe connection arrangement further comprising
- a second double-walled connecting pipe (180) having a first end and a second end, the first end being connectable to the first connecting block (120) and the second end being connectable to the second connecting block (140), the second connecting pipe (180) comprising an inner pipe (181 ) for conveying liquid fuel from the engine (1 ) and an outer pipe (182) arranged around the inner pipe (181 ) such that a leakage space (183) is formed between the inner pipe (181 ) and the outer pipe (182), wherein at the first end of the second connecting pipe (180) the inner pipe (181 ) is connectable to the second fuel outlet (132) of the first connecting block (120) and at the second end of the second connecting pipe (180) the inner pipe (181 ) is connectable to the second fuel inlet (151 ) of the second connecting block (140), and
- a second inert gas pipe (184) having a first end and a second end, the first end being connectable to the second inert gas inlet (134) or outlet (135) of the first connecting block (120) and the second end being connectable to the second inert gas outlet (155) or inlet (154) of the second connecting block (140), wherein the second connecting block (140) further comprises a second leakage channel (159) having an inlet (157) and an outlet (158), the inlet (157) being configured to be arranged in fluid communication with the leakage space (183) of the second connecting pipe (180), the second leakage channel (159) comprising a closure element (160) having a closed position, in which flow between said inlet (157) and outlet (158) is prevented, and an open position, in which flow between said inlet (157) and outlet (158) is allowed, the closure element (160) being configured to move from the closed position to the open position when the pressure on the inlet side of the closure element (160) exceeds a predetermined threshold.
5. A pipe connection arrangement according to claim 4, wherein the second connecting block (140) is configured such that an inner pipe (186) of a double-walled fuel return pipe (185) can be connected to the second fuel outlet (152) of the second connecting block (140) and a leakage space (188) formed between the inner pipe (186) and an outer pipe (187) of said fuel return pipe (185) can be connected to the second inert gas inlet (154) or outlet (155) of the second connecting block (140), and the outlet (158) of the second leakage channel (159) is arranged such that the second leakage channel (159) is in fluid communication with the leakage space (188) of the fuel return pipe (185) in a mounted state of the fuel return pipe (185).
6. A pipe connection arrangement according to any of claims 3-5, wherein the second connecting block (140) comprises a leak indicator (162) connected to the second leakage channel (159).
7. A fuel supply system for an internal combustion engine (1 ), wherein the fuel supply system comprises a pipe connection arrangement according to any of the preceding claims and a fuel supply pipe (175) connected to the second connecting block (140).
8. An internal combustion engine (1 ) comprising a fuel supply system according to claim 7.
9. A method of operating an internal combustion engine (1 ) according to claim 8, wherein the method comprises the steps of
- filling leakage spaces (178, 188) of the fuel supply system with inert gas, apart from the leakage spaces (173, 183) between the second connecting block (140) and the first connecting block (140) to create an inert atmosphere into the filled leakage spaces (178, 188) (101 ),
- supplying fuel to the engine via said fuel supply pipe (175) (102),
- maintaining the inert atmosphere in the leakage spaces (178, 188) while the engine (1 ) is operated using the fuel supplied via said fuel supply pipe (175) (103).
10. A method according to claim 9, wherein leakages into the leakage space (173) of the connecting pipe (170) are monitored, and in case a leakage is detected, the leakage space (173) is purged by introducing inert gas into the leakage space (173).
EP23723224.4A 2023-05-08 2023-05-08 Pipe connection arrangement, fuel supply system, internal combustion engine and method of operating an internal combustion engine Pending EP4709978A1 (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/FI2023/050249 WO2024231591A1 (en) 2023-05-08 2023-05-08 Pipe connection arrangement, fuel supply system, internal combustion engine and method of operating an internal combustion engine

Publications (1)

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EP4709978A1 true EP4709978A1 (en) 2026-03-18

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ID=86332170

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Application Number Title Priority Date Filing Date
EP23723224.4A Pending EP4709978A1 (en) 2023-05-08 2023-05-08 Pipe connection arrangement, fuel supply system, internal combustion engine and method of operating an internal combustion engine

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EP (1) EP4709978A1 (en)
KR (1) KR20260003288A (en)
CN (1) CN121175484A (en)
WO (1) WO2024231591A1 (en)

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Publication number Priority date Publication date Assignee Title
DE502006008159D1 (en) * 2005-03-24 2010-12-09 Ems Chemie Ag Use of a piping system for volatile fluids
EP2011996B1 (en) * 2007-07-04 2012-03-14 Caterpillar Motoren GmbH & Co. KG Fuel system for a combustion engine having local leakage detection
ES2536309T3 (en) * 2011-11-04 2015-05-22 Caterpillar Motoren Gmbh & Co. Kg Double wall fuel supply pipe element

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KR20260003288A (en) 2026-01-06
WO2024231591A1 (en) 2024-11-14
CN121175484A (en) 2025-12-19

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