DK181408B1 - Internal combustion engine and a method for starting up an internal combustion engine - Google Patents

Internal combustion engine and a method for starting up an internal combustion engine Download PDF

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Publication number
DK181408B1
DK181408B1 DKPA202070399A DKPA202070399A DK181408B1 DK 181408 B1 DK181408 B1 DK 181408B1 DK PA202070399 A DKPA202070399 A DK PA202070399A DK PA202070399 A DKPA202070399 A DK PA202070399A DK 181408 B1 DK181408 B1 DK 181408B1
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DK
Denmark
Prior art keywords
cylinder
chamber
engine
heat exchange
fuel gas
Prior art date
Application number
DKPA202070399A
Other languages
Danish (da)
Inventor
Bach Mellergaard Simon
Anthony Ramos De Matos Oftedal Michael
Schierup Jakob
Pedersen Carsten
Original Assignee
Man Energy Solutions Filial Af Man Energy Solutions Se Tyskland
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Application filed by Man Energy Solutions Filial Af Man Energy Solutions Se Tyskland filed Critical Man Energy Solutions Filial Af Man Energy Solutions Se Tyskland
Priority to CN202010661375.8A priority Critical patent/CN112211720A/en
Priority to KR1020200085567A priority patent/KR20210008318A/en
Priority to JP2020119009A priority patent/JP2021014851A/en
Publication of DK202070399A1 publication Critical patent/DK202070399A1/en
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Publication of DK181408B1 publication Critical patent/DK181408B1/en

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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
    • F02B19/00—Engines characterised by precombustion chambers
    • F02B19/10—Engines characterised by precombustion chambers with fuel introduced partly into pre-combustion chamber, and partly into cylinder
    • F02B19/1004—Engines characterised by precombustion chambers with fuel introduced partly into pre-combustion chamber, and partly into cylinder details of combustion chamber, e.g. mounting arrangements
    • F02B19/1009—Engines characterised by precombustion chambers with fuel introduced partly into pre-combustion chamber, and partly into cylinder details of combustion chamber, e.g. mounting arrangements heating, cooling
    • 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
    • F02B43/00—Engines characterised by operating on gaseous fuels; Plants including such engines
    • 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
    • Y02T10/12—Improving ICE efficiencies
    • 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

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Output Control And Ontrol Of Special Type Engine (AREA)
  • Combustion Methods Of Internal-Combustion Engines (AREA)

Abstract

Disclosed is a two-stroke uniflow scavenged crosshead internal combustion engine comprising at least one cylinder, a cylinder cover, a piston, a fuel gas supply system, a cylinder cooling system, a pre-chamber, and a scavenge air system. The engine further comprises a pre-chamber temperature regulating system for regulating the temperature of the pre-chamber, the pre-chamber temperature regulating system comprising a heat exchange channel in proximity to the pre-chamber for exchanging heat with the pre-chamber, the pre-chamber temperature regulating system being configured to circulate a heat exchange fluid through the heat exchange channel, wherein the pre-chamber temperature regulating system further comprises a control unit configured to control the flow of the heat exchange fluid and / or the inlet temperature of the heat exchange fluid.

Description

DK 181408 B1 1
Field
The present invention relates to a two-stroke uniflow scavenged crosshead internal combustion engine and a method of starting up a dual-fuel two-stroke uniflow scavenged crosshead internal combustion engine.
Background
Two-stroke internal combustion engines are used as propulsion engines in vessels like container ships, bulk carriers, and tankers. Reduction of unwanted exhaust gases from the internal combustion engines has become increasingly important.
An effective way to reduce the amount of unwanted exhaust gasses is to switch from fuel oil e.g. Heavy Fuel Oil (HFO) to fuel gas. Fuel gas may be injected into the cylinders at the end of the compression stroke where it may be immediately ignited by either the high temperatures which the gases in the cylinders achieve when compressed or by the ignition of a pilot fuel. However, injecting fuel gas into the cylinders at the end of the compression stroke requires high pressure compressors for compressing the fuel gas prior to injection to overcome the high pressure in the cylinders.
The high pressure gas compressors are however expensive and complex to manufacture and maintain. One way to avoid the need of high pressure compressors is to configure the engine to inject the fuel gas in the beginning of the compression stroke where the pressure in the cylinders is significantly lower.
WO2013007863 discloses such an engine. To secure proper ignition of the fuel gas a pilot ignition pre-chamber is provided in the cylinder cover. An amount of pilot fuel oil is injected into the pilot ignition pre-chamber
DK 181408 B1 2 which then self-ignites due to the temperature and pressure in the pilot ignition pre-chamber. This results in a torch which ignites the fuel gas in the main chamber of the cylinder.
Securing proper cooling of the pre-chamber is however difficult.
Thus it remains a problem to provide an improved way of cooling pre-chambers.
Summary
According to a first aspect, the invention relates to a two-stroke uniflow scavenged crosshead internal combustion engine comprising at least one cylinder, a cylinder cover, a piston, a fuel gas supply system, , a pre- chamber, and a scavenge air system, the cylinder having a cylinder wall, the cylinder cover being arranged on top of the cylinder and having an exhaust valve, the piston being movably arranged within the cylinder along a central axis between bottom dead center and top dead center, the scavenge air system having a scavenge air inlet arranged at the bottom of the cylinder, the fuel gas supply system comprising a fuel gas valve arranged at least partly in the cylinder wall and configured to inject fuel gas into the cylinder during the compression stroke enabling the fuel gas to mix with scavenge air and allowing the mixture of scavenge air and fuel gas to be compressed before being ignited, the pre-chamber opening into the cylinder through a first opening, the pre-chamber being configured to ignite the mixture of scavenge air and fuel gas in the cylinder wherein the engine further comprises a pre- chamber temperature regulating system for regulating the temperature of the pre-chamber, the pre-chamber temperature regulating system comprising a heat exchange channel in proximity to the pre-chamber for exchanging heat with the pre-chamber, the pre-chamber temperature regulating system being configured to circulate a heat exchange fluid through the heat exchange channel, wherein the pre-chamber temperature regulating system further
DK 181408 B1 3 comprises a control unit configured to control the flow of the heat exchange fluid and / or the inlet temperature of the heat exchange fluid.
Consequently, by providing the pre-chamber with a dedicated temperature regulating system secure and efficient ignition in the pre- chamber may be obtained e.g. the temperature of the pre-chamber may be controlled independent on the operation of other cooling systems such as a cylinder cooling system. The improved control may further allow the temperature of the pre-chamber to be lowered further towards an ignition limit (e.g. the required self-ignition temperature of a pilot fuel) whereby emission of NOx gases may be reduced. The improved control may also lower the risk of pre-ignition which both rises the NOx formation and results in increase engine wear.
The internal combustion engine is preferably a large low-speed turbocharged two-stroke crosshead internal combustion engine with uniflow scavenging for propelling a marine vessel or stationary power plant having a power of at least 400 kW per cylinder. The internal combustion engine may comprise a turbocharger driven by the exhaust gases generated by the internal combustion engine and configured to compress the scavenge air.
The internal combustion engine may be a dual-fuel engine having an Otto
Cycle mode when running on fuel gas and a Diesel Cycle mode when running on an alternative fuel e.g. heavy fuel oil or marine diesel oil. Such dual-fuel engine has its own dedicated fuel supply system for injecting the alternative fuel. The internal combustion engine may comprise a cylinder cooling system. The pre-chamber temperature regulating system may be configured to only regulating the temperature of the pre-chamber (and possibly engine parts surrounding the pre-chamber directly or indirectly).
The internal combustion engine preferably comprises a plurality of cylinders e.g. between 4 and 14 cylinders. The internal combustion engine further comprises for each cylinder of the plurality of cylinders a cylinder cover, an exhaust valve, a piston, a fuel gas valve, and a scavenge air inlet.
DK 181408 B1 4
The fuel gas supply system is preferably configured to inject the fuel gas via one or more fuel gas valves under sonic conditions, i.e. a velocity equal to the speed of sound, i.e. a constant velocity. Sonic conditions may be achieved when the pressure drop ratio across the nozzle throat (minimum area of cross section) is larger than approximately two.
In some embodiments the one or more fuel gas valves are configured to inject a fuel gas into the cylinder during the compression stroke within O degrees to 160 degrees from bottom dead center, within O degrees to 130 degrees from bottom dead center or within O degrees to 90 degrees from bottom dead center.
The one or more fuel gas valves are arranged at least partly in the cylinder wall between top dead center and bottom dead center, preferably in a position above the scavenge air inlet. The one or more fuel gas valves may comprise a nozzle arranged in the cylinder wall for injecting fuel gas into the cylinder. The other parts of the fuel gas valve (other than the nozzle) may be arranged outside the cylinder wall.
Examples of fuel gases are Liquefied Natural Gas (LNG), methane, ammonia, ethane, and Liquefied Petroleum Gas (LPG).
In some embodiments the engine further comprises a pilot fuel supply system, the pilot fuel supply system comprises a pilot fuel valve arranged in the pre-chamber, the pilot fuel valve being configured to inject a pilot fuel into the pre-chamber.
The pre-chamber may be configured so that the pilot fuel self- ignite due to the temperature and pressure in the pre-chamber. Alternatively, the pilot fuel in the pre-chamber may be ignited by means comprising a spark plug or a laser igniter. The pilot fuel may be heavy fuel oil or marine diesel oil, or any other fuel with suitable ignitability, accurately measured out so the amount just is able to ignite the mixture of fuel gas and scavenge air in the cylinder. Such a pilot fuel system may in size be much smaller and more suitable for injecting a precisely amount of pilot fuel compared to a dedicated fuel supply system for an alternative fuel, which due to the large size of the
DK 181408 B1 components may not suitable for this purpose. The pilot fuel supply system may be configured to inject an amount of pilot oil at a suitable crank angle for the optimal ignition of the main charge, close to the top dead centre. The pilot fuel ignition immediately follows the pilot oil injection, and the main charge 5 ignition immediately follows the pilot oil ignition.
The pre-chamber may be arranged in the cylinder wall or in the cylinder cover.
In some embodiments the control unit is configured to control the flow of the heat exchange fluid and / or the inlet temperature of the heat exchange fluid dependent on the engine load, the engine speed, the air—fuel equivalence ratio, A, of the mixture of scavenge air and fuel gas, and / or sensor signals.
In some embodiments the pre-chamber is at least partly arranged in the cylinder wall, the first opening being formed in the cylinder wall.
In some embodiments the pre-chamber temperature regulating system is configured to cool the pre-chamber.
The pre-chamber temperature regulating system may be a cooling system configured to cool the pre-chamber e.g. the cooling system may be configured to cool the heat exchange fluid before providing the heat exchange fluid to the heat exchange channel. Thus, heat exchange channel may be a cooling channel.
Alternatively, the heat exchange channel may be part of a combined heating and cooling system configured to either cool or heat the pre-chamber e.g. the combined heating and cooling system may be configured to either cool or heat the heat exchange fluid before providing the heat exchange fluid to the heat exchange channel. The combined heating and cooling system may be configured to heat the pre-chamber as part of the gas start-up procedure either from a complete engine stop or when switching from heavy fuel oil or marine diesel oil to fuel gas. The combined heating and cooling system may be configured to cool the pre-chamber after the gas
DK 181408 B1 6 start-up procedure has been completed, i.e. during normal gas operation, to prevent damage to the pre-chamber and / or surrounding engine parts.
In some embodiments the heat exchange channel may be part of a combined heating and cooling system configured to either cool or heat the pre-chamber, wherein the combined heating and cooling system is configured to heat the pre-chamber when the engine is running at low load and configured to cool the pre-chamber when the engine is running at a high load.
Consequently, by ensuring the pre-chamber is warm enough — when running the engine at a low load the combustion stability may be increased and the ignition delay may be reduced and stabilized. Furthermore, by cooling the pre-chamber when the engine is running at a high load damage to the pre-chamber and surrounding engine parts may be prevented.
In some embodiments the combined heating and cooling system — is configured to heat the pre-chamber when the engine is running at a load below a first threshold and configured to cool the pre-chamber when the engine is running above a second threshold, wherein the second threshold is higher or equal to the first threshold.
The values of the first and the second threshold is dependent on — the specific engine design and may be found via experiments and / or computer simulations.
Examples of heat exchange fluids are water, air and system oil.
In some embodiments the pre-chamber temperature regulating system is further configured to heat the pre-chamber.
In some embodiments the pre-chamber temperature regulating system is further configured to heat the pre-chamber as part of an engine start-up procedure.
In some embodiments the engine further comprises a cylinder cooling system comprising a cooling channel in proximity to the cylinder for cooling the cylinder, the cylinder cooling system being configured to circulate a heat exchange fluid through the cooling channel, wherein the cylinder cooling
DK 181408 B1 7 system further comprises a control unit configured to control the flow of the heat exchange fluid and / or the inlet temperature of the heat exchange fluid.
Consequently, the pre-chamber and the cylinder may both be at least partly independently cooled e.g. dependent on values of engine parameters, whereby better engine performance may be achieved.
The cylinder cooling system is preferable also configured to cool the cylinder cover.
In some embodiments the cylinder cooling system and the pre- chamber temperature regulating system are two separate systems that are — not fluidly connected.
Consequently, the pre-chamber and the cylinder may both be fully independent cooled.
In some embodiments the cylinder cooling system and the pre- chamber temperature regulating system form part of a common engine temperature regulating system comprising a first pressure regulating valve configured to control the inlet pressure of the heat exchange fluid provided to either the heat exchange channel of the pre-chamber temperature regulating system or the cooling channel of the cylinder cooling system.
Consequently, the cooling system of the engine may be simplified while still provide partly independent control of the cooling of the cylinder and the pre-chamber.
In some embodiments the pre-chamber has a pre-chamber wall, where the heat exchange channel is extending inside a part the pre-chamber wall.
Consequently, by having the heat exchange channel directly arranged inside the pre-chamber wall, the temperature of the pre-chamber may be effectively and precisely regulated.
The part of the heat exchange channel extending inside the pre- chamber wall may be formed at the same time as the pre-chamber is formed e.g. using additive manufacturing techniques.
DK 181408 B1 8
In some embodiments the engine further comprises a pre-chamber housing, the pre-chamber being arranged in the pre-chamber housing, the pre-chamber having at least a first contact portion and a second contact portion for abutting the pre-chamber housing and securing the pre-chamber inthe pre-chamber housing, wherein the pre-chamber housing has a first insulation volume formed between the first contact portion and the second contact portion for limiting heat-exchange between the pre-chamber and the engine.
Consequently, by insulating the pre-chamber from the part of the — engine where it is inserted the temperature of the pre-chamber may more precisely be controlled. This may also allow the parts of the engine in proximity of the pre-chamber to be made of materials having lower heat tolerances such as cast iron.
In some embodiments the pre-chamber further has a third contact — portion for abutting the pre-chamber housing, wherein the pre-chamber housing further has a second insulation volume formed between the second contact portion and the third contact portion.
In some embodiments the pre-chamber and the heat exchange channels are produced by in a single additive manufacturing process.
In some embodiments the at least one cylinder has a base member and a pre-chamber member, the pre-chamber member being arranged on top of the base member and the cylinder cover being arranged on top of the pre-chamber member, and wherein the pre-chamber is at least partly arranged in the cylinder wall of the pre-chamber member, the first opening is opening into the cylinder through an opening formed in the cylinder wall of the pre-chamber member.
This allows the pre-chamber member to be specifically designed to handle the high temperature and pressure within the pre-chamber, e.g. by selecting suitable materials. This may further make it easier to perform maintenance on the pre-chambers. The pre-chamber member may be an insert between the base member and the cylinder cover, with or without
DK 181408 B1 9 gasket arrangements towards either. It may be pre-assembled with the base member before the cylinder cover is installed.
In some embodiments the pre-chamber member of the cylinder is made of a different material than the base member of the cylinder.
The base member of the cylinder may be made of cast iron and the pre-chamber member may be made of steel.
In some embodiments the pre-chamber is connected to the first opening via a channel extending along a first axis, wherein the angle between the first axis and a reference plane arranged perpendicular to the central axis is between O degrees and 85 degrees, 0 and 80 degrees, 0 degrees and 60 degrees, 0 degrees and 45 degrees, or 0 degrees and 30 degrees.
Consequently the torch extending from the pre-chamber into the cylinder may come into direct contact with a large portion of the mixture of scavenge air and fuel gas.
The engine may be provided with more pre-chamber members e.g. at least two, three or four pre-chambers per cylinder.
According to a second aspect the invention relates to a method of starting up a dual-fuel two-stroke uniflow scavenged crosshead internal combustion engine having a Otto Cycle mode when running on fuel gas and a Diesel Cycle mode when running on an alternative fuel, the engine comprising at least one cylinder, a cylinder cover, a piston, a fuel gas supply system, a cylinder cooling system, a pre-chamber, and a scavenge air system, the cylinder having a cylinder wall, the cylinder cover being arranged ontop of the cylinder and having an exhaust valve, the piston being movably arranged within the cylinder along a central axis between bottom dead center and top dead center, the scavenge air system having a scavenge air inlet arranged at the bottom of the cylinder, the fuel gas supply system comprising a fuel gas valve arranged at least partly in the cylinder wall and configured to inject fuel gas into the cylinder during the compression stroke enabling the fuel gas to mix with scavenge air and allowing the mixture of scavenge air
DK 181408 B1 10 and fuel gas to be compressed before being ignited, the pre-chamber opening into the cylinder through a first opening, the pre-chamber being configured to ignite the mixture of scavenge air and fuel gas in the cylinder, wherein the engine further comprises a dedicated alternative fuel supply system for injecting the alternative fuel directly into the cylinder and wherein the pre-chamber is heated as part of the engine start up procedure and wherein the engine is started directly in fuel gas mode without first injecting the alternative fuel into the cylinder using the dedicated alternative fuel supply system.
Consequently, by heating up the pre-chamber the engine may be directly started in gas-mode lowering emissions of unwanted exhaust gases.
This may be especially beneficial if the engine it started up in an emission sensitive area such as a cruise port located close to residential areas.
The engine may be an engine as disclosed in relation to relation to the first aspect of the invention.
The different aspects of the present invention can be implemented in different ways including as two-stroke uniflow scavenged crosshead internal combustion engines and a method of starting up a dual- fuel two-stroke uniflow scavenged crosshead internal combustion engine, each yielding one or more of the benefits and advantages described in connection with at least one of the aspects described above, and each having one or more preferred embodiments corresponding to the preferred embodiments described in connection with at least one of the aspects described above and/or disclosed in the dependent claims. Furthermore, it will be appreciated that embodiments described in connection with one of the aspects described herein may equally be applied to the other aspects.
There will always be two angles between two axes, two planes, or an axis and a plane, a small angle V1 and a large angle V2, where V2=180 degrees-V1. In this disclosure, it will always be the small angle V1 that is specified.
DK 181408 B1 11
Brief description of the drawings
The above and/or additional objects, features and advantages of the present invention, will be further elucidated by the following illustrative and non- limiting detailed description of embodiments of the present invention, with reference to the appended drawings, wherein:
Fig. 1 shows schematically a cross-section of a two-stroke internal combustion engine according to an embodiment of the invention.
Fig. 2 shows a schematic cross-section of a part of a two-stroke crosshead internal combustion engine with uniflow scavenging according to an embodiment of the present invention.
Fig. 3 shows a schematic cross-section of a part of a two-stroke crosshead internal combustion engine with uniflow scavenging according to an embodiment of the present invention.
Fig. 4 shows a schematic cross-section of a part of a two-stroke crosshead internal combustion engine with uniflow scavenging according to an embodiment of the present invention.
Fig. 5 shows a flowchart of a method of starting up a dual-fuel two-stroke uniflow scavenged crosshead internal combustion engine according to an embodiment of the present invention.
Figs. 6a-b show a cross-section of a large low-speed turbocharged two- stroke crosshead internal combustion engine with uniflow scavenging for propelling a marine vessel according to an embodiment of the present invention.
Detailed description
In the following description, reference is made to the accompanying figures, — which show by way of illustration how the invention may be practiced.
DK 181408 B1 12
Fig. 1 shows schematically a cross-section of a large low-speed turbocharged two-stroke crosshead internal combustion engine with uniflow scavenging 100 for propelling a marine vessel according to an embodiment of the present invention. The engine 100 comprises a scavenge air system 111, an exhaust gas receiver 108, a fuel gas supply system, and a turbocharger 109. The engine has a plurality of cylinders 101 (only a single cylinder is shown in the cross-section). Each cylinder 101 has a cylinder wall 115 and comprises a scavenge air inlet 102 arranged at the bottom of the cylinder 101. The engine further comprises for each cylinder a cylinder cover 112 and a piston 103. The cylinder cover 112 being arranged on top of the cylinder 101 and having an exhaust valve 104. The piston 103 being movably arranged within the cylinder along a central axis 113 between bottom dead center and top dead center. The fuel gas supply system comprises one or more fuel gas valves 105 (only schematically shown) configured to inject fuel gas into the cylinder 101 during the compression stroke enabling the fuel gas to mix with scavenge air and allowing the mixture of scavenge air and fuel gas to be compressed before being ignited. The fuel gas valves 105 are arranged at least partly in the cylinder wall between the cylinder cover 112 and the scavenge air inlet 102. The engine further comprises a pre-chamber 114 arranged in the cylinder wall 115 (only schematically shown). The pre- chamber 114 has a pre-chamber wall and opens into the cylinder through a first opening. The pre-chamber 114 being configured to ignite the mixture of scavenge air and fuel gas in the cylinder 101. The engine 100 further comprises a pre-chamber temperature regulating system for regulating the temperature of the pre-chamber, the pre-chamber temperature regulating system comprising a heat exchange channel 191 (only schematically shown) in proximity to the pre-chamber 114 for exchanging heat with the pre- chamber 114, the pre-chamber temperature regulating system being configured to circulate a heat exchange fluid through the heat exchange channel 191. The pre-chamber temperature regulating system further comprises a control unit 190 configured to control the flow of the heat
DK 181408 B1 13 exchange fluid and / or the inlet temperature of the heat exchange fluid e.g. by controlling a compressor and / or an expansion valve of the pre-chamber temperature regulating system. The scavenge air inlet 102 is fluidly connected to the scavenge air system. The piston 103 is shown in its lowest position (bottom dead center). The piston 103 has a piston rod connected to a crankshaft (not shown). The fuel gas valves 105 are configured to inject fuel gas into the cylinder during the compression stroke enabling the fuel gas to mix with scavenge air and allowing the mixture of scavenge air and fuel gas to be compressed before being ignited. The fuel gas valves 105 are preferably configured to inject a fuel gas into the cylinder 101 in the beginning of the compression stroke within O degrees to 130 degrees from bottom dead center, i.e. when the crankshaft has rotated between O degrees and 130 degrees from its orientation at bottom dead center. Preferably the fuel gas valves 105 are configured to start injecting fuel gas after the crankshaft axis has rotated a few degrees from bottom dead center so that the piston has moved past the scavenge air inlets 102 to prevent fuel gas from exiting through the exhaust valve 104 and scavenge air inlets 102. The scavenge air system 111 comprises a scavenge air receiver 110 and an air cooler 106.
The engine 100 is preferably a dual-fuel engine having an Otto Cycle mode when running on fuel gas and a Diesel Cycle mode when running on an alternative fuel e.g. heavy fuel oil or marine diesel oil. Such dual-fuel engine has its own dedicated alternative fuel supply system for injecting the alternative fuel. Thus optionally the engine 100 further comprise one or more fuel injectors 116 arranged in the cylinder cover 112 forming part of an alternative fuel supply system. When the engine 100 runs on the alternative fuel the fuel injectors 116 are configured to inject the alternative fuel e.g. heavy fuel oil at the end of the compression stroke under high pressure.
Fig. 2 shows a schematic cross-section of a part of a two-stroke crosshead internal combustion engine with uniflow scavenging according to an embodiment of the present invention. Shown is a cylinder 101, a cylinder
DK 181408 B1 14 cover 112, a piston 103, and an exhaust valve 104. The piston 103 is positioned in top dead centre. The cylinder 101 has a cylinder wall 115 provided with a first a pre-chamber 114 and a second pre-chamber 116, the first and second pre-chamber 114 116 each being provided with a heat exchange channel (not shown). The first and second pre-chamber 114 116 both opens into the cylinder 101 through an opening formed in the cylinder wall 115, the pre-chambers are configured to ignite the mixture of scavenge air and fuel gas in the cylinder.
Fig. 3 shows a schematic cross-section of a part of a two-stroke crosshead internal combustion engine with uniflow scavenging according to an embodiment of the present invention. The part corresponds to the part shown in Fig. 2 with the difference that the cylinder 101 has a base member 117 and pre-chamber member 118, the pre-chamber member 118 being arranged on top of the base member 117 and the cylinder cover 112 being arranged on top of the pre-chamber member 118. The first and second pre- chamber 114 116 being arranged in the cylinder wall of the pre-chamber member 118. This allows the pre-chamber member to be specifically designed to handle the high temperature and pressure within the pre- chamber, e.g. by selecting suitable materials.
Fig. 4 shows a schematic cross-section of a part of a two-stroke crosshead internal combustion engine with uniflow scavenging according to an embodiment of the present invention. The part corresponds to the part shown in Fig. 2 with the difference that the first and second pre-chamber 114 116 are arranged in the cylinder cover 112.
Fig. 5 shows a flowchart of a method of starting up a dual-fuel two- stroke uniflow scavenged crosshead internal combustion engine according to an embodiment of the present invention. The engine may be an engine as disclosed in relation to Fig. 1. In the first step 501 a pre-chamber of the engine is heated e.g. using a heat exchange channel provided in proximity to the pre-chamber. Next in step 502, the engine is started directly in fuel gas mode without first injecting an alternative fuel into the cylinder using a
DK 181408 B1 15 dedicated alternative fuel supply system. Consequently, by heating up the pre-chamber the engine may be directly started in gas-mode lowering emissions of unwanted exhaust gases. This may be especially beneficial if the engine it started up in an emission sensitive area such as a cruise port located close to residential areas.
Fig. 6a shows a cross-section of a large low-speed turbocharged two- stroke crosshead internal combustion engine with uniflow scavenging for propelling a marine vessel according to an embodiment of the present invention. The engine is a dual-fuel engine having an Otto Cycle mode when running on fuel gas and a Diesel Cycle mode when running on an alternative fuel e.g. heavy fuel oil or marine diesel oil. Each cylinder has a cylinder wall and comprises a scavenge air inlet arranged at the bottom of the cylinder (not shown). The engine further comprises for each cylinder a cylinder cover 112 and a piston 103. The cylinder cover 112 being arranged on top of the cylinder and having an exhaust valve 104. The piston 103 being movably arranged within the cylinder along a central axis between bottom dead center and top dead center. In the figure, the piston 103 is arranged at top dead center. The fuel gas supply system comprises one or more fuel gas valves (not shown) configured to (when the engine is in gas mode) inject fuel gas into the cylinder during the compression stroke enabling the fuel gas to mix with scavenge air and allowing the mixture of scavenge air and fuel gas to be compressed before being ignited. The fuel gas valves are arranged at least partly in the cylinder wall between the cylinder cover 112 and the scavenge air inlet. The engine further comprises two pilot pre-chamber units 131 each — pilot pre-chamber unit 131 comprises a pre-chamber 114, a pilot fuel valve housing 130, and a pilot fuel valve 132 arranged in the pilot fuel valve housing 130. The cylinder has a base member 117 and a pre-chamber member 118, the pre-chamber member 118 being arranged on top of the base member 117 and the cylinder cover 112 being arranged on top of the pre-chamber member 118. The pre-chambers 114 are arranged in the cylinder wall of the pre-chamber member 118. The pre-chambers 114
DK 181408 B1 16 opening into the cylinder through an opening formed in the cylinder wall of the pre-chamber member 118. The scavenge air inlet is fluidly connected to the scavenge air system. The piston 103 is via a piston rod, a crosshead and a connecting rod connected to a crankshaft (not shown). The pilot fuel valves 132 are configured to at least when the engine is in gas mode inject a small amount of pilot fuel into the pre-chambers 114. The pilot fuel valves 132 may also be configured to inject a small amount of pilot fuel into the pre-chambers 114 when the engine is running on pure diesel to prevent the pilot fuel valves to get stuck. The pre-chambers 114 are configured so that the pilot fuel self- ignite due to the temperature and pressure in the pre-chamber 114. The pilot fuel oil may be heavy fuel oil, marine diesel oil, or any other fuel with suitable self-ignitability.
The engine further comprises one or more fuel injectors 116 arranged in the cylinder cover 112 forming part of an alternative fuel supply system.
When the engine 100 runs on the alternative fuel the fuel injectors 116 are configured to inject the alternative fuel e.g. heavy fuel oil at the end of the compression stroke under high pressure.
Fig. 6b shows a close-up of the right pilot pre-chamber unit 131 shown in Fig. 7a. The pre-chamber pilot unit 131 comprises a first heat exchange channel 145 for circulating a temperature regulating fluid having an inlet 136 and an outlet (not shown), and where both the inlet 136 and the outlet is arranged in the pilot fuel valve housing 130. The pre-chamber pilot unit 131 further comprises a second heat exchange channel 146 for circulating a temperature regulating fluid having an inlet 138 and an outlet (not shown), and where both the inlet 138 and the outlet is arranged in the pilot fuel valve housing 130. The first and second heat exchange channel 145 146 are extending inside both a part of the wall of the pre-chamber 114 and a part of the pilot fuel valve housing 130. The first and second heat exchange channel 145 146 form part of a pre-chamber temperature regulating system for regulating the temperature of the pre-chamber 114. The pre-chamber temperature regulating system being configured to circulate a heat exchange
DK 181408 B1 17 fluid through the first and the second heat exchange channel 145 146. The pre-chamber temperature regulating system further comprises a control unit (not shown) configured to control the flow of the heat exchange fluid e.g. the flow speed of the heat exchange fluid through the first and the second heat exchange channel 145 146 and / or the inlet temperature of the heat exchange fluid provided to the first and the second heat exchange channel 145 146. The first and second heat exchange channel 145 146 comprises a first part for guiding the temperature regulating fluid towards the first opening 144 of the pre-chamber and a second portion for guiding the temperature regulating fluid away from the first opening of the pre-chamber (only the first part can be seen in this cross-section). The shape of the first portion substantially corresponds to the shape of the second portion. In this embodiment, the pre-chamber member 118 functions as a pre-chamber housing, the pre-chamber 114 being arranged in the pre-chamber housing, the pre-chamber 114 having a first contact portion 143 and a second contact portion 142 for abutting the pre-chamber housing and securing the pre- chamber in the pre-chamber housing. In this embodiment both the first contact portion 143 and the second contact portion 142 has an annular shape. The pre-chamber housing has a first insulation volume 141 (e.g. filed with air) formed between the first contact portion 143 and the second contact portion 142 for limiting heat-exchange between the pre-chamber 114 and the engine. The pre-chamber further has a third contact portion 147 for abutting the pre-chamber housing. In this embodiment the third contact portion 147 has an annular shape. The pre-chamber housing further has a second
Insulation volume 140 formed between the second contact portion 142 and the third contact portion 147.
Although some embodiments have been described and shown in detail, the invention is not restricted to them, but may also be embodied in other ways within the scope of the subject matter defined in the following claims. In particular, it is to be understood that other embodiments may be
DK 181408 B1 18 utilised and structural and functional modifications may be made without departing from the scope of the present invention.
In device claims enumerating several means, several of these means can be embodied by one and the same item of hardware. The mere fact that — certain measures are recited in mutually different dependent claims or described in different embodiments does not indicate that a combination of these measures cannot be used to advantage.
It should be emphasized that the term "comprises/comprising" when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

Claims (12)

DK 181408 B1 19 Patentkrav:DK 181408 B1 19 Patent claim: 1. Længdeskyllet totakts-krydshovedforbrændingsmotor (100) — omfattende mindst en cylinder (101), et cylinderdæksel (112), et stempel (103), et brændstofgasforsyningssystem, et forkammer (114) og et skylleluftsystem (111), hvor cylinderen (101) har en cylindervæg (115), hvor cylinderdæksiet (112) er arrangeret på toppen af cylinderen og har en udstødningsventil (104), hvor stemplet (103) er bevægeligt arrangeret inden — cylinderen (101) langs en central akse mellem bunddødpunkt og topdødpunkt, hvor skylleluftsystemet har et skylleluftindiøb (102) arrangeret ved bunden af cylinderen (101), hvor brændstofgasforsyningssystemet omfatter en brændstofgasventil (105) som er anbragt mindst delvist cylindervæggen (115) og er konfigureret til at indsprøfte brændstofgas ind — cylinderen (101) under kompressionsslaget, hvilket gør det muligt for brændstofgassen at blande sig med skylleluften og tillader at blandingen af skylleluft og brændstofgas komprimeres før den antændes, hvor forkammeret åbner ind til cylinderen (101) gennem en første åbning (144), hvor forkammeret (114) er konfigureret til at antænde blandingen af skylleluft og — brændstofgas i cylinderen (101), hvor motoren yderligere omfatter et pilotbrændstofforsyningssystem, hvor pilotbrændstofforsyningssystemet omfatter en pilotbrændstofventil (132) arrangeret i forkammeret (114), hvor pilotbrændstofventilen (132) er konfigureret til at indsprøjte et selv- antændeligt pilotbrændstof ind i forkammeret (114), ke n de te gn e t ved, at motoren yderligere omfatter et forkammertemperaturreguleringssystem til at regulere temperaturen af forkammeret (114), hvor forkammertemperaturreguleringssystemet omfatter en varmevekslingskanal (191) nær forkammeret (114) til al veksle varme med forkammeret (114), hvor forkammertemperaturreguleringssystemet er konfigureret til at cirkulere — et varmeveksiingsfluid gennem varmevekslingskanalen (191), hvor forkammertemperaturreguleringssystemet yderligere omfatter en1. Longitudinally scavenged two-stroke crosshead internal combustion engine (100) — comprising at least one cylinder (101), a cylinder head (112), a piston (103), a fuel gas supply system, a prechamber (114) and a scavenge air system (111), wherein the cylinder (101) has a cylinder wall (115) in which the cylinder cover (112) is arranged on top of the cylinder and has an exhaust valve (104) in which the piston (103) is movably arranged within the cylinder (101) along a central axis between bottom dead center and top dead center, where the scavenge air system has a scavenge air port (102) arranged at the bottom of the cylinder (101), the fuel gas supply system comprising a fuel gas valve (105) which is located at least partially in the cylinder wall (115) and is configured to inject fuel gas into the cylinder (101) during the compression stroke, which allowing the fuel gas to mix with the purge air and allowing the purge air/fuel gas mixture to be compressed before igniting, the prechamber opening into the cylinder (101) through a first port (144), the prechamber (114) being configured to ignite the mixture of scavenging air and — fuel gas in the cylinder (101), wherein the engine further comprises a pilot fuel supply system, wherein the pilot fuel supply system comprises a pilot fuel valve (132) arranged in the pre-chamber (114), wherein the pilot fuel valve (132) is configured to inject a self-igniting pilot fuel in the pre-chamber (114), characterized in that the engine further comprises a pre-chamber temperature control system for regulating the temperature of the pre-chamber (114), where the pre-chamber temperature control system comprises a heat exchange channel (191) near the pre-chamber (114) to exchange heat with the pre-chamber ( 114), wherein the prechamber temperature control system is configured to circulate — a heat exchange fluid through the heat exchange channel (191), wherein the prechamber temperature control system further comprises a DK 181408 B1 20 styringsenhed (190) som er konfigureret til at styre strømningen af varmevekslingsfluidet og/eller indløbstemperaturen af varmevekslingsfluidet, og hvor styringsenheden (190) er konfigureret til at sænke temperaturen af forkammeret (114) mod selvantændelsestemperaturen af pilotbrændstoffet.DK 181408 B1 20 control unit (190) which is configured to control the flow of the heat exchange fluid and/or the inlet temperature of the heat exchange fluid, and where the control unit (190) is configured to lower the temperature of the pre-chamber (114) towards the self-ignition temperature of the pilot fuel. 2. Længdeskyllet totakts-krydshovedforbrændingsmotor (100) ifølge krav 1, hvor styringsenheden (190) er konfigureret til at styre strømningen af varmevekslingsfluidet og/eller indløbstemperaturen af varmevekslingsfluidet afhængigt af motorbelastningen, motorhastigheden, — luft-brændstof-ækvivalensforholdet, A, af blandingen af skylleluft og brændstofgas og/eller sensorsignaler.2. The longitudinally scavenged two-stroke crosshead internal combustion engine (100) of claim 1, wherein the control unit (190) is configured to control the flow of the heat exchange fluid and/or the inlet temperature of the heat exchange fluid depending on the engine load, the engine speed, — the air-fuel equivalence ratio, A, of the mixture of purge air and fuel gas and/or sensor signals. 3. Længdeskyllet totakts-krydshovedforbrændingsmotor (100) ifølge krav 1 eller 2, hvor forkammeret (114) er mindst delvist arrangeret i — cylindervæggen (115), hvor den første åbning (144) er dannet i cylindervæggen (115).3. A longitudinally flushed two-stroke crosshead internal combustion engine (100) according to claim 1 or 2, wherein the prechamber (114) is at least partially arranged in — the cylinder wall (115), wherein the first opening (144) is formed in the cylinder wall (115). 4. Længdeskyllet totakts-krydshovedforbrændingsmotor (100) ifølge et hvilket som helst af krav 1 til 3, hvor > forkammertemperaturreguleringssystemet er konfigureret til at køle forkammeret (114).A longitudinally scavenged two-stroke crosshead internal combustion engine (100) according to any one of claims 1 to 3, wherein > the pre-chamber temperature control system is configured to cool the pre-chamber (114). 5. Længdeskyllet totakts-krydshovedforbrændingsmotor (100) ifølge krav 4, hvor forkammertemperaturreguleringssystemet yderligere er — konfigureret til at varme forkammeret (114).The longitudinally scavenged two-stroke crosshead internal combustion engine (100) of claim 4, wherein the prechamber temperature control system is further — configured to heat the prechamber (114). 6. Længdeskyllet totakts-krydshovedforbrændingsmotor (100) ifølge krav 5, hvor forkammertemperaturreguleringssystemet yderligere er konfigureret til at varme forkammeret (114) som en del af en — motoropstartsprocedure.6. The longitudinally scavenged two-stroke crosshead internal combustion engine (100) of claim 5, wherein the prechamber temperature control system is further configured to heat the prechamber (114) as part of an — engine start-up procedure. DK 181408 B1 21DK 181408 B1 21 7. Længdeskyllet totakts-krydshovedforbrændingsmotor (100) ifølge et hvilket som helst af krav 1 til 6, hvor motoren yderligere omfatter et cylinderkølesystem omfattende en kølekanal nær cylinderen til at køle cylinderen (101), hvor cylinderkølesystemet er konfigureret til at cirkulere et — varmevekslingsfluid gennem kølekanalen, hvor cylinderkølesystemet yderligere omfatter en styringsenhed (190) som er konfigureret til at styre strømningen af varmevekslingsfluid og/eller indløbstemperaturen af varmevekslingsfluidet.The longitudinally scavenged two-stroke crosshead internal combustion engine (100) according to any one of claims 1 to 6, wherein the engine further comprises a cylinder cooling system comprising a cooling channel near the cylinder for cooling the cylinder (101), the cylinder cooling system being configured to circulate a — heat exchange fluid through the cooling channel, wherein the cylinder cooling system further comprises a control unit (190) configured to control the flow of heat exchange fluid and/or the inlet temperature of the heat exchange fluid. 8. Længdeskyllet totakts-krydshovedforbrændingsmotor (100) ifølge krav 7, hvor cylinderkølesystemet og forkammertemperaturreguleringssystemet er to separate systemer som ikke er fluidmæssigt forbundet.8. Longitudinally flushed two-stroke cross-head combustion engine (100) according to claim 7, wherein the cylinder cooling system and the pre-chamber temperature control system are two separate systems which are not fluidically connected. 9. Længdeskyllet totakts-krydshovedforbrændingsmotor (100) ifølge et hvilket som helst af krav 1 til 8, hvor forkammeret (114) har en forkammervæg, hvor varmevekslingskanalen strækker sig inde i en del af forkammervæggen.A longitudinally scavenged two-stroke crosshead internal combustion engine (100) according to any one of claims 1 to 8, wherein the prechamber (114) has a prechamber wall, the heat exchange channel extending within a portion of the prechamber wall. 10. Længdeskyllet totakts-krydshovedforbrændingsmotor (100) ifølge et hvilket som helst af krav 1 til 8, hvor motoren yderligere omfatter et forkammerhus, hvor forkammeret (114) er arrangeret i forkammerhuset, hvor forkammeret (114) har mindst en første kontaktdel (143) og en anden kontaktdel (142) til at ligge an mod forkammerhuset og sikre forkammeret (114) i forkammerhuset, hvor forkammerhuset har et første isoleringsvolumen (140) dannet mellem den første kontaktdel (143) og den anden kontaktdel (142) for at begrænse varmeveksling mellem forkammeret (114) og cylinderen (101).The longitudinally scavenged two-stroke crosshead internal combustion engine (100) according to any one of claims 1 to 8, wherein the engine further comprises a prechamber housing, wherein the prechamber (114) is arranged in the prechamber housing, the prechamber (114) having at least a first contact portion (143). and a second contact part (142) for abutting against the antechamber housing and securing the antechamber (114) in the antechamber housing, the antechamber housing having a first insulating volume (140) formed between the first contact part (143) and the second contact part (142) to limit heat exchange between the pre-chamber (114) and the cylinder (101). DK 181408 B1 22DK 181408 B1 22 11. Længdeskyllet totakts-krydshovedforbrændingsmotor (100) ifølge et hvilket som helst af krav 1 til 10, hvor varmevekslingskanalen (191) kan være en del af et kombineret varme- og kølesystem som er konfigureret til enten at køle eller at varme forkammeret (114), hvor det kombinerede — varme- og kølesystem er konfigureret til at varme forkammeret (114) når motoren kører med lav belastning og konfigureret til at køle forkammeret (114) når motoren kører med høj belastning.The longitudinally scavenged two-stroke crosshead internal combustion engine (100) according to any one of claims 1 to 10, wherein the heat exchange duct (191) may be part of a combined heating and cooling system configured to either cool or heat the prechamber (114). , wherein the combined heating and cooling system is configured to heat the prechamber (114) when the engine is running at low load and configured to cool the prechamber (114) when the engine is running at high load. 12. Fremgangsmåde til opstart af en længdeskyllet — dobbeltbrændstof-totakts-krydshovedforbrændingsmotor (100) som har en Otto-cyklustilstand når den kører på brændstofgas, og en Diesel- cyklustilstand når den kører på et alternativt brændstof, hvor motoren omfatter mindst én cylinder (101), et cylinderdæksel (112), et stempel (103), et brændstofgasforsyningssystem, et cylinderkølesystem, et forkammer (114) — og et skylleluftsystem (111), hvor cylinderen (101) har en cylindervæg (115), hvor cylinderdækslet (112) er arrangeret på toppen af cylinderen og har en udstødningsventil (104), hvor stemplet (103) er bevægeligt arrangeret inden i cylinderen (101) langs en central akse mellem bunddødpunkt og topdødpunkt, hvor skylleluftsystemet har et skylleluftindløb (102) arrangeret ved bunden af cylinderen (101), hvor brændstofgasforsyningssystemet omfatter en brændstofgasventil (105) som er anbragt mindst delvist i cylindervæggen (115) og er konfigureret til at indsprøjte brændstofgas ind i cylinderen (101) under kompressionsslaget, hvilket gør det muligt for brændstofgassen at blande sig med skylleluften og tillader at blandingen af — skylleluft og brændstofgas komprimeres før den antændes, hvor forkammeret åbner ind til cylinderen (101) gennem en første åbning (144), hvor forkammeret (114) er konfigureret til at antænde blandingen af skylleluft og brændstofgas i cylinderen (101), hvor motoren (100) yderligere omfatter en dedikeret alternativt brændstofforsyningssystem til at indsprøjte det alternative brændstof direkte ind i cylinderen, hvor motoren (100) yderligere omfatter et pilotbrændstofforsyningssystem, hvor12. Method for starting a longitudinally scavenged — dual-fuel two-stroke crosshead internal combustion engine (100) having an Otto cycle mode when running on fuel gas and a Diesel cycle mode when running on an alternative fuel, wherein the engine includes at least one cylinder (101 ), a cylinder cover (112), a piston (103), a fuel gas supply system, a cylinder cooling system, a pre-chamber (114) — and a scavenging air system (111), where the cylinder (101) has a cylinder wall (115), where the cylinder cover (112) is arranged on the top of the cylinder and has an exhaust valve (104) where the piston (103) is movably arranged inside the cylinder (101) along a central axis between bottom dead center and top dead center, where the scavenge air system has a scavenge air inlet (102) arranged at the bottom of the cylinder (101), wherein the fuel gas supply system comprises a fuel gas valve (105) disposed at least partially in the cylinder wall (115) and configured to inject fuel gas into the cylinder (101) during the compression stroke, allowing the fuel gas to mix with the scavenge air and allowing the mixture of — scavenge air and fuel gas to be compressed before igniting, the pre-chamber opening to the cylinder (101) through a first opening (144), the pre-chamber (114) being configured to ignite the mixture of scavenge air and fuel gas in the cylinder (101) , wherein the engine (100) further comprises a dedicated alternative fuel supply system for injecting the alternative fuel directly into the cylinder, wherein the engine (100) further comprises a pilot fuel supply system, wherein DK 181408 B1 23 pilotbrændstofforsyningssystemet omfatter en pilotbrændstofventil (132) arrangeret i forkammeret (114), hvor pilotbrændstofventilen (132) er konfigureret til at indsprøjte et selv-antændeligt pilotbrændstof ind i forkammeret (114), ken de te g net ved, at motoren yderligere omfatter — etforkammertemperaturreguleringssystem til at regulere temperaturen af forkammeret (114), hvor forkammertemperaturreguleringssystemet omfatter en varmevekslingskanal (191) nær forkammeret (114) til at veksle varme med forkammeret (114), hvor forkammertemperaturreguleringssystemet er konfigureret til at cirkulere et varmevekslingsfluid gennemDK 181408 B1 23 the pilot fuel supply system comprises a pilot fuel valve (132) arranged in the antechamber (114), wherein the pilot fuel valve (132) is configured to inject a self-igniting pilot fuel into the antechamber (114), characterized in that the engine further comprising — a pre-chamber temperature control system for regulating the temperature of the pre-chamber (114), the pre-chamber temperature control system comprising a heat exchange channel (191) near the pre-chamber (114) for exchanging heat with the pre-chamber (114), the pre-chamber temperature control system being configured to circulate a heat exchange fluid through — varmevekslingskanalen (191), hvor forkammertemperaturreguleringssystemet yderligere omfatter en styringsenhed (190) som er konfigureret til at styre strømningen af varmevekslingsfluidet og/eller indløbstemperaturen af varmevekslingsfluidet, og hvor styringsenheden (190) er konfigureret til at sænke temperaturen af forkammeret (114) mod selvantændelsestemperaturen af pilotbrændstoffet efter motoren har startet, og hvor forkammeret (114) opvarmes som en del af opstartsproceduren for motoren (100) og hvor motoren (100) startes direkte i brændstofgastilstanden uden først at indsprøjte det alternative brændstof ind i cylinderen (101) ved anvendelse af det dedikerede alternative breendstofforsyningssystem.— the heat exchange channel (191), wherein the pre-chamber temperature control system further comprises a control unit (190) which is configured to control the flow of the heat exchange fluid and/or the inlet temperature of the heat exchange fluid, and where the control unit (190) is configured to lower the temperature of the pre-chamber (114) towards the auto-ignition temperature of the pilot fuel after the engine has started and wherein the prechamber (114) is heated as part of the start-up procedure for the engine (100) and wherein the engine (100) is started directly in the fuel gas mode without first injecting the alternative fuel into the cylinder (101) using the dedicated alternative fuel supply system.
DKPA202070399A 2019-07-11 2020-06-17 Internal combustion engine and a method for starting up an internal combustion engine DK181408B1 (en)

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