DK202200999A1 - A large turbocharged two-stroke uniflow crosshead internal combustion engine and method for operating such engine - Google Patents
A large turbocharged two-stroke uniflow crosshead internal combustion engine and method for operating such engine Download PDFInfo
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- DK202200999A1 DK202200999A1 DKPA202200999A DKPA202200999A DK202200999A1 DK 202200999 A1 DK202200999 A1 DK 202200999A1 DK PA202200999 A DKPA202200999 A DK PA202200999A DK PA202200999 A DKPA202200999 A DK PA202200999A DK 202200999 A1 DK202200999 A1 DK 202200999A1
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- cylinder
- alternative fuel
- alternative
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- 238000002485 combustion reaction Methods 0.000 title claims abstract description 28
- 238000000034 method Methods 0.000 title claims description 4
- 239000000446 fuel Substances 0.000 claims abstract description 254
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims abstract description 42
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims abstract description 27
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims abstract description 27
- 229910021529 ammonia Inorganic materials 0.000 claims abstract description 21
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims abstract description 12
- OTMSDBZUPAUEDD-UHFFFAOYSA-N Ethane Chemical compound CC OTMSDBZUPAUEDD-UHFFFAOYSA-N 0.000 claims abstract description 9
- 238000007599 discharging Methods 0.000 claims abstract description 6
- XTHFKEDIFFGKHM-UHFFFAOYSA-N Dimethoxyethane Chemical compound COCCOC XTHFKEDIFFGKHM-UHFFFAOYSA-N 0.000 claims abstract 3
- 230000001131 transforming effect Effects 0.000 abstract description 3
- LCGLNKUTAGEVQW-UHFFFAOYSA-N Dimethyl ether Chemical compound COC LCGLNKUTAGEVQW-UHFFFAOYSA-N 0.000 description 16
- 239000007789 gas Substances 0.000 description 12
- 239000000295 fuel oil Substances 0.000 description 7
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N dimethylmethane Natural products CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 6
- NNPPMTNAJDCUHE-UHFFFAOYSA-N trimethylmethane Natural products CC(C)C NNPPMTNAJDCUHE-UHFFFAOYSA-N 0.000 description 6
- 230000009977 dual effect Effects 0.000 description 5
- 238000002347 injection Methods 0.000 description 5
- 239000007924 injection Substances 0.000 description 5
- 239000007791 liquid phase Substances 0.000 description 5
- 238000010926 purge Methods 0.000 description 5
- 238000010521 absorption reaction Methods 0.000 description 4
- 239000010763 heavy fuel oil Substances 0.000 description 4
- 239000007788 liquid Substances 0.000 description 4
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 230000006835 compression Effects 0.000 description 2
- 238000007906 compression Methods 0.000 description 2
- 239000012530 fluid Substances 0.000 description 2
- 230000002000 scavenging effect Effects 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 238000010531 catalytic reduction reaction Methods 0.000 description 1
- 230000001276 controlling effect Effects 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 239000002283 diesel fuel Substances 0.000 description 1
- 239000003623 enhancer Substances 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B37/00—Engines characterised by provision of pumps driven at least for part of the time by exhaust
- F02B37/04—Engines with exhaust drive and other drive of pumps, e.g. with exhaust-driven pump and mechanically-driven second pump
- F02B37/10—Engines with exhaust drive and other drive of pumps, e.g. with exhaust-driven pump and mechanically-driven second pump at least one pump being alternatively or simultaneously driven by exhaust and other drive, e.g. by pressurised fluid from a reservoir or an engine-driven pump
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D15/00—Adaptations of machines or engines for special use; Combinations of engines with devices driven thereby
- F01D15/08—Adaptations for driving, or combinations with, pumps
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B25/00—Engines characterised by using fresh charge for scavenging cylinders
- F02B25/02—Engines characterised by using fresh charge for scavenging cylinders using unidirectional scavenging
- F02B25/04—Engines having ports both in cylinder head and in cylinder wall near bottom of piston stroke
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D19/00—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
- F02D19/06—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures peculiar to engines working with pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed
- F02D19/0639—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures peculiar to engines working with pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed characterised by the type of fuels
- F02D19/0642—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures peculiar to engines working with pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed characterised by the type of fuels at least one fuel being gaseous, the other fuels being gaseous or liquid at standard conditions
- F02D19/0644—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures peculiar to engines working with pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed characterised by the type of fuels at least one fuel being gaseous, the other fuels being gaseous or liquid at standard conditions the gaseous fuel being hydrogen, ammonia or carbon monoxide
-
- 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
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/30—Use of alternative fuels, e.g. biofuels
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Combustion & Propulsion (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Output Control And Ontrol Of Special Type Engine (AREA)
- Supercharger (AREA)
- Fuel-Injection Apparatus (AREA)
Abstract
Described is a large turbocharged two-stroke uniflow crosshead internal combustion engine, which has at least one mode of operation in which the main fuel is an alternative fuel, such as ammonia, methanol, ethanol, DME, methane, ethane or LPG, the engine comprising at least one cylinder with a cylinder liner (1), a reciprocating piston (10) therein and a cylinder cover (22) covering the cylinder, a combustion chamber formed inside the cylinder between the reciprocating piston (10) and the cylinder cover (22), an alternative fuel system (30) configured for supplying pressurized alternative fuel to at least one fuel valve (50) that is arranged in the cylinder cover (22) or in the cylinder liner (1) for introducing alternative fuel into the cylinder, said alternative fuel system (30) comprising a number of hydraulically powered fuel pumps (61, 33, 35), an exhaust system with an exhaust valve (4) for discharging exhaust gas from the combustion chamber, a turbocharger (5) having a turbine (6) and a shaft (24), which turbine (6) is driven by exhaust gas and which drives a compressor (7) for scavenge air via the shaft (24). The engine is peculiar in that it comprises a hydraulic pump (62), which is coupled to the shaft (24) of the turbocharger (5) and delivers hydraulic power to at least some of the hydraulically powered fuel pumps (61, 33, 35) of the alternative fuel system (30) when the engine is operated on an alternative fuel as main fuel. Hence, the required HPS capacity for operation on an alternative fuel can be achieved without or with a low increase of the SFOC. This is because the additional required hydraulic power is obtained by recovering and transforming a portion of the energy in the exhaust gas into hydraulic power by means of a hydraulic pump driven by the turbocharger.
Description
DK 2022 00999 A1 1
The present invention relates to a large turbocharged two-stroke uniflow crosshead internal combustion engine, which has at least one mode of operation in which the main fuel is an alternative fuel, such as ammonia, methanol, ethanol, DME, methane, ethane or LPG, the engine comprising at least one cylinder with a cylinder liner, a reciprocating piston therein and a cylinder cover covering the cylinder, a combustion chamber formed inside the cylinder between the reciprocating piston and the cylinder cover, an alternative fuel system configured for supplying pressurized alternative fuel to at least one fuel valve that is arranged in the cylinder cover or in the cylinder liner for introducing alternative fuel into the cylinder, said alternative fuel system comprising a number of hydraulically powered fuel pump, an exhaust system with an exhaust valve for discharging exhaust gas from the combustion chamber, a turbocharger having a turbine and a shaft, which turbine is driven by exhaust gas and which drives a compressor for scavenge air via the shaft.
Large turbocharged two-stroke uniflow crosshead internal combustion engine are typically used as prime movers in large ocean going ships, such as container ships or in power plants. Very often, these engines are operated with heavy fuel oil or with fuel oil, such as diesel.
Recently, there has been a demand for large two-stroke diesel engines to be able to handle alternative types of fuel, such as ammonia, methanol, ethanol, DME, methane, ethane or LPG and/or other similar fuels. An engine, which is operable in both a fuel oil mode, in which it is operated only on fuel oil and an alternative fuel mode, in which it is operated on alternative fuel and pilot fuel oil, is often referred to as a dual fuel engine. It is a required that a dual fuel engine can run on both a conventional fuel, such as e.g. heavy fuel oil or diesel and on one of the mentioned alternative and potentially more environmental friendly fuels. Thus, a dedicated fuel supply and injection system is required for each of the fuel types used. This requirement for a two separate fuel supply and injection systems significantly increases the initial costs for constructing the engine and increases the engines complexity and maintained costs. However,
DK 2022 00999 A1 2 some of the equipment, such as hydraulic pumps, may be used in connection with both fuel supply and injection systems for delivering hydraulic power to fuel pumps for pressurizing the fuel.
Dual fuel engines, which has at least one mode of operation in which the main fuel is an alternative fuel, all have separate fuel systems for these alternative fuels. The calorific value of these alternative fuels as compared with conventional fuels, such as heavy fuel oil or diesel, is much lower and accordingly, a correspondingly higher volume of fuel has to be pumped through the alternative fuel system and injected into the cylinder of the engine, when it is operated on alternative than when it is operated on conventional fuels in order to obtain the same engine power. Thus, such dual fuel engines have a demand for an increase in capacity of hydraulic power supply (HPS). The increase in HPS capacity for such dual fuel engines results in a demand for increased pump numbers and size to a point where it is not possible to install the capacity on the existing HPS chain drive. The extra capacity needed does also require more power delivered to the HPS increasing the SFOC (Specific Fuel Oil Consumption) when operating in alternative fuel — operation.
The invention also relates to a method for operating a large turbocharged two-stroke uniflow crosshead internal combustion engine as described above and claimed in the attached claims.
It is an object of the present invention to provide a large turbocharged two-stroke uniflow crosshead internal combustion engine of the kind mentioned in the introduction, where the above mentioned challenges relating to the demand for an increase in capacity of hydraulic power — supply are at least significantly reduced.
The foregoing and other objects are achieved by the features of the independent claims. Further implementation forms are apparent from the dependent claims, the description, and the figures.
According to a first aspect, there is provided a large turbocharged two-stroke uniflow crosshead internal combustion engine, which has at least one mode of operation in which the main fuel is an alternative fuel, such as ammonia, methanol, ethanol, DME, methane, ethane or LPG, the engine comprising at least one cylinder with a cylinder liner, a reciprocating piston therein and a cylinder cover covering the cylinder, a combustion chamber formed inside the cylinder between
DK 2022 00999 A1 3 the reciprocating piston and the cylinder cover, an alternative fuel system configured for supplying pressurized alternative fuel to at least one fuel valve that is arranged in the cylinder cover or in the cylinder liner for introducing alternative fuel into the cylinder, said alternative fuel system comprising a number of hydraulically powered fuel pumps, an exhaust system with an exhaust valve for discharging exhaust gas from the combustion chamber, a turbocharger having a turbine and a shaft, which turbine is driven by exhaust gas and which drives a compressor for scavenge air via the shaft, and being characterized in that said engine comprises a hydraulic pump, which is coupled to the shaft of the turbocharger and delivers hydraulic power to at least some of the hydraulically powered fuel pumps of the alternative fuel system when the engine is operated on an alternative fuel as main fuel.
Hence, the required HPS capacity for operation on an alternative fuel can be achieved without or with a low increase of the SFOC. This is because the additional required hydraulic power is obtained by recovering and transforming a portion of the energy in the exhaust gas into hydraulic power by means of a hydraulic pump driven by the turbocharger.
The alternative fuel system may further comprise a number of additional fuel pumps, which may be electrically and/or hydraulically powered.
The engine may comprise a pilot fuel system for use when the engine is operated on alternative fuel, which pilot fuel system may comprise a number of fuel pumps, which may be electrically and/or hydraulically powered.
Further, the engine may comprise a conventional fuel system for use when the engine is operated on conventional fuel, which convention fuel system may comprise a number of fuel pumps, which may be electrically and/or hydraulically powered.
The engine may comprise a number of additional hydraulic pumps, which are driven by power takeoff from the engine, e.g. by a chain- or gear drive connecting said hydraulic pumps to the engine crankshaft.
All hydraulically powered fuel pumps of the engine, i.e. alternative fuel pumps, pilot fuel pumps and conventional fuel pumps may be powered by a hydraulic pump, which is coupled to the shaft of the turbocharger.
DK 2022 00999 A1 4
The hydraulically powered fuel pump may in a preferred embodiment of the invention be arranged in the at least one fuel valve that is arranged in the cylinder cover or in the cylinder liner for introducing alternative fuel into the cylinder.
Further, the engine may comprise a hydraulically powered exhaust valve actuation system for actuation of the exhaust valve, which system is operated both when the engine is running on the conventional fuel and when the engine is running on the alternative fuel, where the hydraulic pump, which is coupled to the shaft of the turbocharger is configured to supply the exhaust valve actuation system with hydraulic power.
The engine may comprise an electronic control unit configured to control the operation of the conventional fuel supply system, the alternative fuel supply system, the exhaust valve actuation system and the hydraulic pump, the electronic control unit being configured to: ramp down the conventional fuel supply system, ramp up the alternative fuel supply system, to divert a portion of the hydraulic power supplied by the hydraulic pump from conventional fuel supply system to the alternative fuel supply system, upon receipt of an instruction to switch operation from the conventional fuel to the alternative fuel. — Further, the electronic control unit is configured to ramp up the conventional fuel supply system, ramp down the alternative fuel supply system, and to divert a portion of the hydraulic power supplied by the hydraulic pump from alternative fuel supply system to the conventional fuel supply system, upon receipt of an instruction to switch operation from the alternative fuel to the conventional fuel.
The alternative fuel supply system may further comprise a hydraulically driven high-pressure fuel pump.
According to a second aspect, there is provided a method for operating a large turbocharged two- stroke uniflow crosshead internal combustion engine, which has at least one mode of operation in which the main fuel is an alternative fuel, such as ammonia, methanol, ethanol, DME, methane, ethane or LPG, the engine comprising at least one cylinder with a cylinder liner, a reciprocating piston therein and cylinder cover covering the cylinder, a combustion chamber formed inside the cylinder between the reciprocating piston and the cylinder cover, an alternative fuel system
DK 2022 00999 A1 configured for supplying pressurized alternative fuel to at least one fuel valve that is arranged in the cylinder cover or in the cylinder liner for introducing alternative fuel into the cylinder, said alternative fuel system comprising a hydraulically powered fuel pump, an exhaust system with an exhaust valve for discharging exhaust gas from the combustion chamber, a turbocharger 5 having a turbine and a shaft, which turbine is driven by exhaust gas and which drives a compressor for scavenge air via the shaft, and being characterized in that hydraulic power is delivered to the hydraulically powered fuel pump of the alternative fuel system from a hydraulic pump, which is coupled to the shaft of the turbocharger, when the engine is operated on an alternative fuel as main fuel.
The invention will be explained in more details with reference to the example embodiments shown in the drawings, in which:
Fig. 1 is an elevated front view of a large two-stroke diesel engine according to an example embodiment.
Fig. 2 is an elevated side view of the large two-stroke engine of Fig. 1.
Fig. 3 is a diagrammatic representation of the large two-stroke engine according to Fig. 1.
Fig. 4 shows schematically the alternative fuel system indicated in Fig. 3.
In the following detailed description, the invention will be described for a large turbocharged two-stroke uniflow crosshead internal combustion engine, but it is understood that the internal combustion engine could be of another type. The large turbocharged two-stroke uniflow crosshead internal combustion engine may both be of the high-pressure type in which fuel is injected at or near top dead center of the pistons and is compression ignited typically by means of a pilot ignition with an ignition fluid, e.g. fuel oil, for ensuring reliable ignition, or of the low- pressure type in which fuel is admitted at relatively low pressure when the piston is on its way towards the top dead center.
DK 2022 00999 A1 6
Figs. 1, 2, and 3 show a large low-speed turbocharged two-stroke diesel engine with a crankshaft 8 and crossheads 9. Fig. 3 shows a diagrammatic representation of a large low-speed turbocharged two-stroke diesel engine with its intake and exhaust systems. In this example embodiment, the engine has six cylinders in line. Large low-speed turbocharged two-stroke diesel engines have typically between four and fourteen cylinders in line, carried by a cylinder frame 23 that is carried by an engine frame 11. The engine may e.g. be used as the main engine in a marine vessel or as a stationary engine for operating a generator in a power station. The total output of the engine may, for example, range from 1,000 to 110,000 kW.
The engine is in this example embodiment a dual-fuel compression-ignited engine of the two- stroke uniflow type with scavenging ports 18 in the lower region of the cylinder liners 1 and a central exhaust valve 4 at the top of each cylinder liner 1. The engine has at least one alternative fuel mode in which the engine is operated on an alternative, such as ammonia, methanol, ethanol,
DME, methane, ethane or LPG and at least one conventional fuel mode in which the engine is operated on conventional fuel, e.g. fuel oil (marine diesel) or heavy fuel oil.
Scavenge air is passed from the scavenge air receiver 2 to the scavenge ports 18 of the individual cylinders 1. A piston 10 that reciprocates in the cylinder liner 1 between the bottom dead center (BDC) and top dead center (TDC) compresses the scavenge air. In the shown embodiment, fuel in form of an alternative fuel, such as ammonia, methanol, ethanol, DME, methane, ethane or
LPG in the alternative fuel mode is injected from an alternative fuel supply system 30 through high-pressure fuel valves 50 that are arranged in the cylinder cover 22 into the combustion chamber in the cylinder liner 1 at or near TDC. In an alternative embodiment, the alternative fuel — fuel may be admitted through fuel valves 50” arranged in the cylinder liner somewhere between the scavenging ports 18 and TDC. Combustion follows and exhaust gas is generated. Each cylinder cover 22 is provided with one or more fuel valves 50. The fuel valves 50 are either configured to inject only one specific type of fuel, e.g. ammonia and in this case, there will also be one or more fuel valves 50 for injecting conventional fuel into the combustion chamber.
Hence, the engine will have two or more fuel valves. In case the fuel valves 50 are suitable for injecting both alternative fuel, such as e.g. ammonia and suitable for injecting conventional fuel there can be one or more fuel valves 50 for each cylinder. The fuel valves 50 are arranged in the cylinder cover 22 around the central exhaust valve 4. Further, additional, typically smaller fuel valves (not shown) are in an embodiment provided in the cylinder cover for injecting ignition
DK 2022 00999 A1 7 fluid, for ensuring reliable ignition of the alternative fuel. The ignition fuel is ordinary diesel fuel but can also be another form of ignition enhancer, such as dimethyl ether (DME) or hydrogen.
Since the engine is a dual-fuel engine it is also provided with a conventional fuel supply system 80 for supplying the conventional fuel to the fuel valves 50. In another embodiment this conventional fuel injection system 80 can also be used to ensure the ignition of the ammonia fuel.
When an exhaust valve 4 is opened, the exhaust gas flows through an exhaust duct associated with the cylinders into the exhaust gas receiver 3 and onwards through a first exhaust conduit 19 via a Selective Catalytic Reduction (SCR) reactor 28 to a turbine 6 of the turbocharger 5, from — which the exhaust gas flows away through a second exhaust conduit via an economizer 20 to an outlet 21 and into the atmosphere. The SCR reactor reduces emissions, in particular NOx emissions.
Through a shaft 24, the turbine 6 drives a compressor 7 supplied with fresh air via an air inlet 12. — The compressor 7 delivers pressurized scavenge air to a scavenge air conduit 13 leading to the scavenge air receiver 2. The scavenge air in the scavenge air conduit 13 passes an intercooler 14 for cooling the scavenge air.
The cooled scavenge air passes via an auxiliary blower 16 driven by an electric motor 17 that pressurizes the scavenge air flow when the compressor 7 of the turbocharger 5 does not deliver sufficient pressure for the scavenge air receiver 2, i.e. in low or partial load conditions of the engine. At higher engine loads the turbocharger compressor 7 delivers sufficient compressed scavenge air and then the auxiliary blower 16 is bypassed via a non-return valve 15 and the electric motor 17 is deactivated.
The alternative fuel supply system is shown in Fig. 4. The conventional fuel system 80 is well known and not shown and described in further detail. The alternative fuel system 30 supplies the fuel valves 50 with liquid phase alternative fuel at a medium supply pressure (e.g. 30 to 80 bar pressure). The engine is of the compression-igniting type and the fuel valves 50 comprise a pressure booster in form of a hydraulically powered fuel pump 61 which is arranged in the fuel valve 50 and significantly raises the pressure of the alternative fuel from the medium pressure to a high pressure to allow the ammonia fuel to be injected at a pressure well above the compression pressure of the engine. Typically, the injection pressure for an ignition-compressing engine is above 300 bar.
DK 2022 00999 A1 8
The alternative fuel system 30 is disclosed in greater detail in Fig. 4. Alternative fuel is stored in the liquid phase in a pressurized storage tank 31 at appropriate pressure, viz. 17 bar in case of ammonia. Ammonia can be stored in the liquid phase at a pressure above 8.6 bar and an ambient temperature of 20°C in an ammonia storage tank 31. However, ammonia is preferably stored at approximately 17 bar or higher to keep it in the liquid phase when the ambient temperature increases.
A low-pressure alternative fuel supply line 32 connects an outlet of the alternative storage tank 31 totheinlet of a medium pressure feed pump 35. A low-pressure feed pump 33 forces the liquid phase alternative fuel from the tank 31, through a filter arrangement 34 to an inlet of the medium pressure feed pump 35. The medium pressure feed pump 35 forces the liquid alternative fuel through a medium pressure ammonia supply line 36 to the fuel valves 50. A portion of the liquid alternative fuel that is supplied to the fuel valves 50 is injected into the combustion chambers of the engine whilst another portion of the liquid alternative fuel that is supplied to the fuel valve 50 is returned to an alternative fuel return line 38 that connects a return port of the fuel valves 50 to the low-pressure supply line 32. Thus, a portion of the liquid alternative fuel is recycled to the inlet of the medium pressure feed pump 35. — When operation on alternative fuel is discontinued, for example due to a failure in the alternative fuel system 30, or another reason for switching to conventional fuel, the alternative fuel system 30 is purged to remove the alternative fuel from the system, e.g. by means of nitrogen from a storage tank 89 through a purging valve 88. Hereto, a purging system is well known and not explained in further details here.
The low-pressure alternative fuel line 32, the medium pressure alternative fuel line 36, and the alternative fuel return line 38 are in a preferred embodiment completely or partially constructed of double-walled piping with a space between an inner pipe and an outer pipe. Preferably, a detection system is provided that detects the presence of alternative fuel in the space between the inner and outer tubing, allowing for discontinuation of the operational alternative fuel if alternative fuel is detected in the space, followed by a subsequent purging of the alternative fuel system and in case of the alternative fuel being ammonia, absorption of the residual ammonia into an absorption purging system, not shown.
DK 2022 00999 A1 9
According to the invention the engine comprises a hydraulic pump 62, which is coupled to the shaft 24 of the turbocharger 5 and delivers hydraulic power to at least some of the hydraulically powered fuel pumps of the alternative fuel system 30 via a hydraulic pipe 60 when the engine is operated on an alternative fuel as main fuel.
Hence, the required hydraulic power is obtained by recovering and transforming a portion of the energy in the exhaust gas into hydraulic power by means of a hydraulic pump driven by the turbocharger.
Inthe shown and preferred embodiment of the invention the hydraulically powered fuel pump 61 is arranged in the fuel valve 50 that is arranged in the cylinder cover 22 or in the cylinder liner 1 for introducing alternative fuel into the cylinder.
In addition or instead, the low-pressure feed pump 33 and the medium pressure feed pump 35 of — the alternative fuel system 30 may be hydraulically powered by means of hydraulic power from the hydraulic pump 62 via the hydraulic pipe 60.
The engine will in most instances comprise a pilot fuel system, not shown, for use when the engine is operated on alternative fuel. Such pilot fuel system may comprise a number of fuel pumps, which are hydraulically powered by means of hydraulic power from the hydraulic pump 62 via the hydraulic pipe 60.
Further, the conventional fuel system 80 for use when the engine is operated on conventional fuel comprises a number of fuel pumps, not shown, which may be hydraulically powered by means — of hydraulic power from the hydraulic pump 62 via the hydraulic pipe 60.
The engine may comprise a number of additional hydraulic pumps, not shown, which are driven by power takeoff from the engine, e.g. by a chain- or gear drive connecting said hydraulic pumps to the engine crankshaft.
Thus, all hydraulically powered fuel pumps of the engine, i.e. alternative fuel pumps, pilot fuel pumps and conventional fuel pumps may be powered by a hydraulic pump, which is coupled to the shaft of the turbocharger.
DK 2022 00999 A1 10
Further, the engine may comprise a hydraulically powered exhaust valve actuation system, not shown, for actuation of the exhaust valve 4, which system is operated both when the engine is running on the conventional fuel and when the engine is running on the alternative fuel, where the hydraulic pump 62, which is coupled to the shaft 24 of the turbocharger 5 is configured to supply the exhaust valve actuation system with hydraulic power.
The engine may comprise an electronic control unit configured to control the operation of the conventional fuel supply system 80, the alternative fuel supply system 30, the exhaust valve actuation system and the hydraulic pump 62, the electronic control unit being configured to: ramp down the conventional fuel supply system, ramp up the alternative fuel supply system, to divert a portion of the hydraulic power supplied by the hydraulic pump 62 from conventional fuel supply system 80 to the alternative fuel supply system 30, upon receipt of an instruction to switch operation from the conventional fuel to the alternative fuel. — An electronic control unit, not shown, is connected via signal lines or wirelessly to the pumps and valves of the fuel system 30, the conventional fuel system 80 and the and the ammonia absorption, if included. The electronic control unit is configured to control these components, e.g. by regulating the speed of the pumps and by controlling the opening and closing of the respective valves, to ensure the operation of the fuel system and the purging and absorption system as described above.
Claims (9)
1. A large turbocharged two-stroke uniflow crosshead internal combustion engine, which has at least one mode of operation in which the main fuel is an alternative fuel, such as ammonia, methanol, ethanol, DME, methane, ethane or LPG, the engine comprising at least one cylinder with a cylinder liner (1), a reciprocating piston (10) therein and a cylinder cover (22) covering the cylinder, a combustion chamber formed inside the cylinder between the reciprocating piston (10) and the cylinder cover (22), an alternative fuel system (30) configured for supplying pressurized alternative fuel to at least one fuel valve (50) that is arranged in the cylinder cover (22) or in the cylinder liner (1) for introducing alternative fuel into the cylinder, said alternative fuel system (30) comprising a number of hydraulically powered fuel pumps (61, 33, 35), an exhaust system with an exhaust valve (4) for discharging exhaust gas from the combustion chamber, a turbocharger (5) having a turbine (6) and a shaft (24), which turbine (6) is driven by exhaust gas and which drives a compressor (7) for scavenge air via the shaft (24), characterized in that said engine comprises a hydraulic pump (62), which is coupled to the shaft (24) of the turbocharger (5) and delivers hydraulic power to at least some of the hydraulically powered fuel pumps (61, 33, 35) of the alternative fuel system (30) when the engine is operated on an alternative fuel as main fuel.
2. The engine according to claim 1, characterized in that the alternative fuel system (30) comprises a number of additional fuel pumps, which may be electrically and/or hydraulically powered.
3. The engine according to claim 1, characterized in that the engine comprises a pilot fuel system for use when the engine is operated on alternative fuel, which pilot fuel system comprises a number of fuel pumps, which are electrically and/or hydraulically powered.
4. The engine according to claim 3, characterized in that the engine comprises a conventional fuel system (80) for use when the engine is operated on conventional fuel, which convention fuel system comprises a number of fuel pumps, which are electrically and/or hydraulically powered.
5. The engine according to claim 1, characterized in that the engine comprises a number of additional hydraulic pumps, which are driven by power takeoff from the engine, e.g. by a chain- or gear drive connecting said hydraulic pumps to the engine crankshaft.
DK 2022 00999 A1 12
6. The engine according to claim 1, characterized in that all hydraulically powered fuel pumps of the engine, i.e. alternative fuel pumps, pilot fuel pumps and conventional fuel pumps may be powered by a hydraulic pump (62), which is coupled to the shaft (24) of the turbocharger (5).
7. The engine according claim 1, characterized in that the hydraulically powered fuel pump (61) is arranged in the at least one fuel valve (50) that is arranged in the cylinder cover (22) or in the cylinder liner (1) for introducing alternative fuel into the cylinder.
8. The engine according to claim 1, characterized in that the alternative fuel supply system (30) further comprises a hydraulically driven high-pressure fuel pump.
9. Method for operating an engine according to any of the preceding claims, which engine has at least one mode of operation in which the main fuel is an alternative fuel, such as ammonia, methanol, ethanol, DME, methane, ethane or LPG, the engine comprising at least one cylinder — with a cylinder liner (1), a reciprocating piston (10) therein and a cylinder cover (22) covering the cylinder, a combustion chamber formed inside the cylinder between the reciprocating piston (10) and the cylinder cover (22), an alternative fuel system (30) configured for supplying pressurized alternative fuel to at least one fuel valve (50) that is arranged in the cylinder cover (22) or in the cylinder liner (1) for introducing alternative fuel into the cylinder, said alternative fuel system (30) comprising a number of hydraulically powered fuel pumps (61, 33, 35), an exhaust system with an exhaust valve (4) for discharging exhaust gas from the combustion chamber, a turbocharger (5) having a turbine (6) and a shaft (24), which turbine (6) is driven by exhaust gas and which drives a compressor (7) for scavenge air via the shaft (24), characterized in that hydraulic power is delivered to at least some of the hydraulically powered fuel pumps (61, 33, 35) of the alternative fuel system from a hydraulic pump (62), which is coupled to the shaft (24) of the turbocharger (5), when the engine is operated on an alternative fuel as main fuel.
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DKPA202200999A DK181415B1 (en) | 2022-11-04 | 2022-11-04 | A large turbocharged two-stroke uniflow crosshead internal combustion engine and method for operating such engine |
| JP2023183615A JP7475530B1 (en) | 2022-11-04 | 2023-10-26 | Large turbocharged two-stroke uniflow crosshead internal combustion engine and its operating method |
| CN202311433223.2A CN117988974A (en) | 2022-11-04 | 2023-10-31 | Large turbocharged two-stroke uniflow crosshead internal combustion engine and method for operating the same |
| KR1020230150445A KR20240064558A (en) | 2022-11-04 | 2023-11-03 | A large turbocharged two-stroke uniflow crosshead internal combustion engine and method for operating such engine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DKPA202200999A DK181415B1 (en) | 2022-11-04 | 2022-11-04 | A large turbocharged two-stroke uniflow crosshead internal combustion engine and method for operating such engine |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| DK202200999A1 true DK202200999A1 (en) | 2023-10-25 |
| DK181415B1 DK181415B1 (en) | 2023-10-25 |
Family
ID=88469869
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| DKPA202200999A DK181415B1 (en) | 2022-11-04 | 2022-11-04 | A large turbocharged two-stroke uniflow crosshead internal combustion engine and method for operating such engine |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JP7475530B1 (en) |
| KR (1) | KR20240064558A (en) |
| CN (1) | CN117988974A (en) |
| DK (1) | DK181415B1 (en) |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5808128B2 (en) | 2011-03-31 | 2015-11-10 | 三菱重工業株式会社 | Gas fired engine |
| JP5965019B1 (en) | 2015-04-06 | 2016-08-03 | 三井造船株式会社 | Fuel supply device |
| DK179683B1 (en) | 2017-09-04 | 2019-03-20 | MAN Energy Solutions | A large two-stroke compression-ignited internal combustion engine with dual fuel systems |
-
2022
- 2022-11-04 DK DKPA202200999A patent/DK181415B1/en active IP Right Grant
-
2023
- 2023-10-26 JP JP2023183615A patent/JP7475530B1/en active Active
- 2023-10-31 CN CN202311433223.2A patent/CN117988974A/en active Pending
- 2023-11-03 KR KR1020230150445A patent/KR20240064558A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| DK181415B1 (en) | 2023-10-25 |
| KR20240064558A (en) | 2024-05-13 |
| CN117988974A (en) | 2024-05-07 |
| JP7475530B1 (en) | 2024-04-26 |
| JP2024068138A (en) | 2024-05-17 |
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