[go: up one dir, main page]

WO2025098645A1 - Method of combusting a first and a second liquid fuel in an internal combustion piston engine - Google Patents

Method of combusting a first and a second liquid fuel in an internal combustion piston engine Download PDF

Info

Publication number
WO2025098645A1
WO2025098645A1 PCT/EP2024/054671 EP2024054671W WO2025098645A1 WO 2025098645 A1 WO2025098645 A1 WO 2025098645A1 EP 2024054671 W EP2024054671 W EP 2024054671W WO 2025098645 A1 WO2025098645 A1 WO 2025098645A1
Authority
WO
WIPO (PCT)
Prior art keywords
injection
fuel
liquid fuel
cylinder
main
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/EP2024/054671
Other languages
French (fr)
Inventor
Diego Delneri
Lauri LEHTOVAARA
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Wartsila Finland Oy
Original Assignee
Wartsila Finland Oy
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Wartsila Finland Oy filed Critical Wartsila Finland Oy
Publication of WO2025098645A1 publication Critical patent/WO2025098645A1/en
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M43/00—Fuel-injection apparatus operating simultaneously on two or more fuels, or on a liquid fuel and another liquid, e.g. the other liquid being an anti-knock additive
    • F02M43/04—Injectors peculiar thereto
    • 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
    • F02D19/0602—Control of components of the fuel supply system
    • F02D19/0607—Control of components of the fuel supply system to adjust the fuel mass or volume flow
    • F02D19/061—Control of components of the fuel supply system to adjust the fuel mass or volume flow by controlling fuel injectors
    • 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
    • F02D19/0649—Liquid fuels having different boiling temperatures, volatilities, densities, viscosities, cetane or octane numbers
    • 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
    • F02D19/0663—Details on the fuel supply system, e.g. tanks, valves, pipes, pumps, rails, injectors or mixers
    • F02D19/0673—Valves; Pressure or flow regulators; Mixers
    • F02D19/0676—Multi-way valves; Switch-over valves
    • 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
    • F02D19/0663—Details on the fuel supply system, e.g. tanks, valves, pipes, pumps, rails, injectors or mixers
    • F02D19/0684—High pressure fuel injection systems; Details on pumps, rails or the arrangement of valves in the fuel supply and return systems
    • 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
    • F02D19/0663—Details on the fuel supply system, e.g. tanks, valves, pipes, pumps, rails, injectors or mixers
    • F02D19/0686—Injectors
    • F02D19/0689—Injectors for in-cylinder direct injection
    • 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
    • F02D19/0663—Details on the fuel supply system, e.g. tanks, valves, pipes, pumps, rails, injectors or mixers
    • F02D19/0686—Injectors
    • F02D19/0694—Injectors operating with a plurality of fuels
    • 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
    • F02D19/08—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 simultaneously using pluralities of fuels
    • F02D19/081—Adjusting the fuel composition or mixing ratio; Transitioning from one fuel to the other
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/0025—Controlling engines characterised by use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/30—Controlling fuel injection
    • F02D41/38—Controlling fuel injection of the high pressure type
    • F02D41/40—Controlling fuel injection of the high pressure type with means for controlling injection timing or duration
    • F02D41/402—Multiple injections
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/30—Controlling fuel injection
    • F02D41/38—Controlling fuel injection of the high pressure type
    • F02D41/40—Controlling fuel injection of the high pressure type with means for controlling injection timing or duration
    • F02D41/402—Multiple injections
    • F02D41/403—Multiple injections with pilot injections
    • 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
    • F02M61/00—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00
    • F02M61/16—Details not provided for in, or of interest apart from, the apparatus of groups F02M61/02 - F02M61/14
    • F02M61/18—Injection nozzles, e.g. having valve seats; Details of valve member seated ends, not otherwise provided for
    • F02M61/1806—Injection nozzles, e.g. having valve seats; Details of valve member seated ends, not otherwise provided for characterised by the arrangement of discharge orifices, e.g. orientation or size
    • F02M61/1846—Dimensional characteristics of discharge orifices
    • 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
    • F02M63/00—Other fuel-injection apparatus having pertinent characteristics not provided for in groups F02M39/00 - F02M57/00 or F02M67/00; Details, component parts, or accessories of fuel-injection apparatus, not provided for in, or of interest apart from, the apparatus of groups F02M39/00 - F02M61/00 or F02M67/00; Combination of fuel pump with other devices, e.g. lubricating oil pump
    • F02M63/02—Fuel-injection apparatus having several injectors fed by a common pumping element, or having several pumping elements feeding a common injector; Fuel-injection apparatus having provisions for cutting-out pumps, pumping elements, or injectors; Fuel-injection apparatus having provisions for variably interconnecting pumping elements and injectors alternatively
    • F02M63/0225—Fuel-injection apparatus having a common rail feeding several injectors ; Means for varying pressure in common rails; Pumps feeding common rails
    • F02M63/0275—Arrangement of common rails
    • F02M63/0285—Arrangement of common rails having more than one common rail
    • F02M63/029—Arrangement of common rails having more than one common rail per cylinder bank, e.g. storing different fuels or fuels at different pressure levels per cylinder bank
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/0025—Controlling engines characterised by use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
    • F02D41/0027—Controlling engines characterised by use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures the fuel being gaseous
    • 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
    • F02M2200/00—Details of fuel-injection apparatus, not otherwise provided for
    • F02M2200/40—Fuel-injection apparatus with fuel accumulators, e.g. a fuel injector having an integrated fuel accumulator
    • 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
    • F02M2200/00—Details of fuel-injection apparatus, not otherwise provided for
    • F02M2200/44—Valves, e.g. injectors, with valve bodies arranged side-by-side

Definitions

  • the present invention relates to method of combusting first liquid fuel and a second liquid fuel in the internal combustion piston engine.
  • An object of the invention is to provide method of combusting a first liquid fuel and a second liquid fuel, the first liquid fuel having its lower heating value less than the second liquid fuel, in the internal combustion piston engine, which results in high performance and low emissions of the combustion.
  • a method of combusting first liquid fuel and a second liquid fuel, the first liquid fuel having its lower heating value less than the second liquid fuel, in the internal combustion piston engine comprises steps, such that a first liquid fuel is injected into a cylinder of the engine as a main fuel which brings a major part of energy to the process, such that total amount of first liquid fuel delivered to the cylinder for one combustion stage is divided into at least two partial injections, wherein o the main injection of the first liquid fuel comprises 70-95 % of the total amount of the first liquid fuel, and o the start of main injection takes place earliest at 20 °CA before top dead center position of a piston in the cylinder, o a pre-injection of the first liquid fuel comprises 5-30% of the total amount of first liquid fuel, and o the start of pre-injection takes place at 20-55 °CA before top dead center position of a piston in the cylinder, and the pre-injection is formed of one injection occurrence, and a second liquid fuel
  • the start the pre-injection of first liquid fuel takes place at 25-35 °CA before top dead center (bTDC) position, preferably at 25-30 °CA before top dead center position, which provides suitable circumstances in the cylinder for the first fuel to form a premixed mixture.
  • the pre-injected portion of first fuel has adequate time to form a premixed air-fuel mixture, combustion of which in the combustion chamber after compression promoted ignition, takes place dominantly as premixed combustion. Fusing into the diffusive combustion of the main injection of the first fuel after compression ignition, the premixed combustion of the pre- injection portion of the first fuel ensures correctly phased pressure rise in the combustion chamber as well as high efficiency and low emissions of the engine.
  • start the main injection of first liquid fuel takes place at 10-0 °CA before top dead center position.
  • main injection of the first liquid fuel is formed of one injection occurrence.
  • main injection of the first liquid fuel is formed of several injection occurrences, start of the first one of the several injection occurrences takes place earliest at 15 °CA bTDC.
  • second liquid fuel injection is formed of one injection occurrence and its duration is 2 to 6°CA.
  • injection of the second liquid fuel ends before start of injection of the main injection of the first fuel, wherein start of injection of the second liquid fuel takes place at 1-5 °CA before start of injection of main injection of the first liquid fuel and duration of injection of the second fuel is 1 to 3°CA.
  • the main injection comprises 85- 90 % of the total amount of first liquid fuel
  • the pre-injection comprises 10- 15% of the total amount of first liquid fuel
  • the pre-injection comprises 10- 15% of the total amount of first liquid fuel and start of pre-injection takes place at 25-30 °CA bTDC.
  • the start the pre-injection of first liquid fuel takes place at 25-35 °CA before top dead center position, and the main injection comprises 85-90 % of the total amount of first liquid fuel, and the pre- injection comprises 10-15% of the total amount of first liquid fuel.
  • the start the pre-injection of first liquid fuel takes place at 25-30 °CA before top dead center position and the main injection comprises 85-90 % of the total amount of first liquid fuel, and the pre- injection comprises 10-15% of the total amount of first liquid fuel.
  • main injection of the first liquid fuel is formed of one injection occurrence and the main injection comprises 85- 90 % of the total amount of first liquid fuel, and the pre-injection comprises 10- 15% of the total amount of first liquid fuel.
  • main injection of the first liquid fuel is formed of one injection occurrence and the main injection comprises 85- 90 % of the total amount of first liquid fuel, and the pre-injection comprises 10- 15% of the total amount of first liquid fuel.
  • main injection of the first liquid fuel is formed of several injection occurrences, start of the first one of the several injection occurrences takes place earliest at 15 °CA bTDC and the main injection comprises 85-90 % of the total amount of first liquid fuel, and the pre-injection comprises 10-15% of the total amount of first liquid fuel.
  • first liquid fuel has its lower heating value ⁇ 33 MJ/kg and second liquid fuel has its lower heating value > 33MJ/kg.
  • the first liquid fuel comprises at least 51 % methanol, preferably is methanol, and start of injection of the second liquid fuel takes place at 1-3 °CA before start of injection of main injection of the first liquid fuel.
  • start of injection is 1-2 °CA before start of injection of main injection.
  • the first liquid fuel comprises at least 51 % methanol and injection pressure of the first liquid fuel is 0,8 MPa - 1 ,2 MPa.
  • the first liquid fuel comprises at least 51% methanol and start of injection of the main injection of the first fuel is dependent of engine load such that at loads greater than 50% of engine’s maximum nominal load, start of injection is delayed at least 5% or 1 °CA compared to start of injection at loads less than or equal to 50%.
  • the first liquid fuel comprises NH 3 and start of injection or second liquid fuel takes place at 3-7 °CA before start of injection of main injection of the first liquid fuel.
  • start of injection is 4-5 °CA before start of injection of main injection.
  • the first liquid fuel comprises at least 51% NH 3 and injection pressure of the first liquid fuel is 1 ,0 MPa - 1 ,7 MPa.
  • the first liquid fuel comprises at least 51 % NH3 and start of injection of the main injection of the first fuel is dependent of engine load such that at loads outside a range of 25 to 60 % of engine’s maximum nominal load, start of injection is advanced 1 - 10 °CA compared to start of injection at loads inside the range.
  • start of main injection takes place between 10 - 0 °CA before top dead center position of a piston in the cylinder.
  • start of main injection of the first liquid fuel takes place before end of injection of the second liquid fuel.
  • a desired cylinder-specific nominal maximum power is determined or set for a cylinder of an engine in which the method is intended to be used, a first injection valve is provided for injecting at least the first fuel, the injection valve comprising
  • area of the fuel outlet is arranging to be 2 - 8,5 mm2/MW, wherein MW is the cylinder-specific nominal maximum power, when in use with the first fuel.
  • the method comprising determining or setting a desired cylinder-specific nominal maximum power for a cylinder of an engine in which the method is intended to be used, providing a first injection valve for injecting at least the first fuel, the injection valve comprising
  • area of the fuel outlet is arranged to be 2 - 8,5 mm2/MW, wherein MW is the cylinder-specific nominal maximum power, when in use with the first fuel, and running the internal combustion engine alternatively using of the following operation modes:
  • the first fuel having its lower heating value lower than the second fuel is according to a preferred embodiment methanol, ammonia or a mixture thereof. Also, mixtures of methanol and light fuel oil or ammonia and light fuel oil has it lower heating value ⁇ 33 MJ/kg, when share of the light fuel oil is 50% or less.
  • Cylinder specific nominal maximum power means the power which engines manufacturer has set as maximum output power of a cylinder.
  • the total output power of the engine is the sum of powers of individual cylinders.
  • a 6-cylinder engine has nominal maximum power of six times of the nominal power of a single cylinder (a power pack).
  • the present invention is particularly advantageous in large internal combustion piston engines running low or medium speed where the absolute time, as well as cylinder volumes for a single combustion cycle affect the combustion chemistry allowing different type of injection phasing than in smaller engines operating at higher rotational speed.
  • Invention is applicable for use in addition to four stroke engines as well as in two stroke engines.
  • LFO as main fuel bar for example 600 - 2300 bar
  • main fuel means fuel which brings the majority of the energy to a combustion chamber.
  • the presented crank angles in this application refer to control values for actuating a fuel injector.
  • Figure 1 illustrates a fuel injection scheme according to an embodiment of the invention
  • FIG. 2 illustrates a fuel injector system according to an embodiment of the invention.
  • Method relates to so called direct injection, which refers to injecting fuel directly to combustion chamber of a cylinder when the piston is approaching to or is approximately at its top dead center (TDC) position after compression stroke, in a four-stroke engine.
  • TDC top dead center
  • a predetermined amount of a first fuel and a second fuel is injected into the cylinder for each combustion stage.
  • the first liquid fuel is injected into a cylinder of the engine as a main fuel which brings a major part of energy to the combustion process.
  • the first liquid fuel has its lower heating value less than the second liquid fuel.
  • the first fuel has its lower heating value ⁇ 33 MJ/kg
  • the second fuel has its lower heating value > 33MJ/kg, preferably > 42MJ/kg.
  • Figure 1 discloses on its horizontal axis a crank angle of preferred range of start of injection and on its vertical axis a relative quantity of the fuel. Each area borders a range within which operation point (fuel relative quantity and start of injection of fuel) of the injection is located.
  • the main injection 10 starts at earliest at 10 °CA bTDC and the range of start of injection is between 10°CA bTDC to TDC and the main injection comprises 70-95% of the total amount of the first liquid fuel.
  • a pre-injec- tion starts at earlies at 55°CA bTDC and its range within which the injection may be started is 35°CA, 55°CA bTDC to 20°CA bTDC.
  • the pre-injection comprises 5-30% of the total amount of first liquid fuel.
  • an injection of the second fuel 14 is taken place, the injection starting at 1-5 °CA before start of injection of the main injection 10 of the first fuel.
  • Amount of the injection of the second fuel corresponds to 3 - 10 % of energy brough by the first fuel into the combustion process.
  • the pre-ignition portion of the first fuel forms a pre-mixed charge in the combustion chamber and is ignited and combusted as pre-mixed combustion.
  • Injection of second fuel before injection of the mail fuel ensures compression ignition and combustion of the pre-mixed charge and diffusion combustion of the main fuel.
  • first fuel is combusted partly i.e. the pre-injection part, as pre-mixed combustion and partly i.e. the main injection part, as diffuse combustion.
  • the pre-injection is formed of one injection occurrence, i.e. not as a so- called split injection.
  • the quantity of the second fuel assisting compression ignition is such that it promotes and ensures compression ignition of the main fuel by affecting circumstances inside the main combustion chamber.
  • the ignition takes place when the pressure, temperatures, fuel mixture and existence of chemically active species (radicals) is suitable to become ignited and support premixed and diffusive combustion.
  • the invention makes it possible to combust a liquid fuel which has substantially low lower heat value i.e. the lower heat value being ⁇ 33 MJ/kg as the first fuel, with assistance of a second fuel having its lower heat value > 33MJ/kg, preferably > 42MJ/kg, and still obtain cylinder specific maximum nominal power which is comparable to e.g. combustion of diesel fuel in corresponding cylinder.
  • Cylinder specific nominal maximum power means the power which engines manufacturer has set as maximum output power of a cylinder.
  • the total output power of the engine is the sum of powers of individual cylinders. For example, a 6-cyl- inder engine has nominal maximum power of six times of the nominal power of a single cylinder (a power pack).
  • Duration of injection of the second fuel is selected in the method such that start of main injection 10 of the first liquid fuel takes place before end of injection of the second liquid fuel. This ensures reliable compression ignition of the fuel admitted to the combustion chamber during the main injection.
  • Figure 1 depicts by the hatched area 10’, 12’, an aspect of the invention with a special range of pre- and main injection of the first fuel according to an aspect of the invention.
  • the special range of the start the pre-injection of first liquid fuel takes place at 25-35 °CA bTDC and its proportion the total amount of first liquid fuel is 10-15 %.
  • the main injection of the first fuel comprises 85-90 % of the total amount of first liquid fuel according to the aspect of the invention.
  • the first fuel is methanol
  • the second fuel is diesel fuel or a like, such as light fuel oil or marine diesel oil.
  • the method comprises a feature that start of injection of the second liquid fuel takes place at 1-3 °CA before start of injection of main injection of the first liquid fuel. That is, when particularly methanol is used as the first fuel the injection of the compression ignition assisting fuel needs to be injected closer to the start of ignition of the main fuel.
  • the first fuel is ammonia
  • the second fuel is diesel fuel or a like, such as light fuel oil or marine diesel oil.
  • the method comprises a feature that start of injection of the second liquid fuel takes place at 3-5 °CA before start of injection of main injection of the first liquid fuel. That is, when particularly ammonia is used as the first fuel the injection of the compression ignition assisting fuel needs to be injected little earlier to the start of ignition of the main fuel.
  • Figure 2 discloses a fuel injector system 10 configured to practise the method according to the engine, for one cylinder.
  • the cylinder is provided with the first injection valve 100 and a second liquid fuel injection valve 200.
  • the first injection valve 100 is configured to inject the main fuel and the second injection valve 200 is configured to inject fuel assisting compression ignition, at least during a normal operation with the first fuel.
  • the first injection valve 100 and the second liquid fuel injection valve 200 may be arranged to separate bodies or in a common injector body, which is preferable because in that way adapting the injection valve to a cylinder head is easier.
  • the first injection valve 100 comprises a fuel inlet 102 and a fuel gallery 104, which is arranged in flow communication with the fuel inlet 102 via a flow path 106 arranged to an injector body (not shown in the figure 2).
  • the flow path is preferably provided with a so-called flow fuse 108, which prevents excess flow of the fuel in case of malfunction of the injection valve 100.
  • the flow path 106 is provided with a pressure accumulator 110 arranged between the fuel gallery 104 and the fuel inlet 102.
  • the pressure accumulator 110 is also arranged between the fuel inlet 102 and the flow fuse 108, such that the volume of the flow channel downstream (in normal operation fuel flow direction) to the flow fuel is smaller and possible leakage fuel amount is thus smaller in case of malfunction.
  • the pressure accumulator serves only for the first injection valve 100 and therefore fuel delivery during injection is ensured.
  • the inlet 102 of the direct injection valve 100 is arranged in controllable flow connection with a source of a first fuel 16 and a source of a second fuel 20, which is shown only schematically in the figure 2. This way the fuel which is injected by the direct injection valve 100 may, if so desired, be selected between the first fuel and the second fuel, or even a blend of the first fuel and the second fuel may be used.
  • the first injection valve 100 is provided with a valve needle 114 which is arranged to close or open a fuel outlet 112 by its axial movement.
  • the valve needle 114 is controlled by hydraulic control system 116.
  • the hydraulic control system may be realized in various manners making use of a principle of creating a biasing force against force created by injection pressure of the fuel.
  • the hydraulic control system is provided with an inlet 118 of pressurized working fluid via which the pressurized working fluid is led to needle housing at the end of the needle opposite to the fuel outlet 112.
  • There is a pressure chamber 124 which is bordered by an end of the needle 114 such that the pressure of the working fluid causes a force to the needle 114.
  • Outlet flow channel 122 of the hydraulic control system 116 is provided with a valve 120 which, when opened, reliefs the pressure from the chamber 124 which causes the needle to move, upwards in the figure, opening the fuel outlet 112.
  • valve 120 When the valve 120 is closed pressure is build up in the chamber 124 urging the needle 114 back to closed position.
  • the working fluid also fills a sealing fluid chamber 126 around upper part of the needle 114 at high pressure than fuel injection pressure so as to prevent the first fuel flowing into hydraulic control system 116 and mixing with the working fluid.
  • a fuel outlet 112 in the valve arranged to open into the fuel gallery 104, which outlet may comprise one or more injection orifices 112.1 , 112.2.
  • the orifice(s) may have circular cross section with a diameter, which defines geometrical cross- sectional area of the orifice.
  • the total area A of the fuel outlet is dimensioned such that it is 2 - 8,5 mm2 I WN, wherein MW is cylinder specific nominal maximum power output, which is determined based on an engine’s specification to which the fuel injection valve is intended to be used.
  • the first injection valve 100 is a multifuel fuel injection arrangement which is dimensioned to produce, in practical circumstances, substantially equal nominal maximum power per cylinder of the engine by combustion of any one of the used fuels. In practical circumstances usual there are two different liquid fuels running the engine.
  • the fuel outlet area in the injection valve is dimensioned based on, using the specific correlation of intended maximum nominal power per cylinder, fuel which as the lowest heating value of the fuels intended to be used which ensures that the injection valve is capable of inject adequate amounts of fuel when in use with any one of the intended fuels, both of low lower heat value and high lower heat value fuels.
  • the area of the fuel outlet 112 is designed based on cylinder specific nominal maximum power, when in use with fuel which has its lower heating value lowest of the different fuels. More precisely, the area A of the fuel outlet 112 is 2 - 8,5 mm2/MW, wherein MW is cylinder-specific nominal maximum power, when in use with fuel which has its lower heating value ⁇ 33 MJ/kg.
  • Fuel pressure is taken into account to dimensioning of the area A such that injection pressure is 600-2500 bar.
  • the pressure range covers different possible variations in fuel viscosity and when in use, suitable amount of fuel in each charged can be fine-tuned by total injection duration.
  • the fuel pressures for the different fuels may be selected close to each other so that the15ifferrent fuels can be more easily directed into the same direct injection valve operating as a multifuel injection valve.
  • One of the fuel pressures, for example, that of second fuel e.g.
  • LFO in the source of a second fuel 20 may be selected to be a bit higher than that of the first fuel (a fuel with low lower heating value) so that the second fuel can be used to displace or flush parts of the fuel system common for both fuels when switching between fuels. This may be important for safety and service points of view as some of the fuel having low lower heating value, such as for example ammonia or methanol, have toxic properties.
  • an engine is intended be operated with at least two fuels, one of which has lower heating value than the other, and the direct injection valve is designed based on the fuel which has its lower heating value lowest of the first fuel and the second fuel.
  • the area A When applied to smaller bore diameter engine, such as 200 mm, in which case the cylinder-specific nominal maximum power is determined to be 150 kW, the area A will be 0,300 - 1 ,275 mm 2 .
  • the area A will be less than 2,60 - 11 ,05 mm 2 . It is preferable that the area is designed near to upper end of obtained range of value A of the area to avoid unnecessarily long injection periods, however some compromise may be acceptable in practice as long as it does not lead to degradation of the combustion process.
  • the second fuel injection valve 200 comprises a needle 204 for administering second fuel into a combustion chamber of the engine.
  • a second fuel gallery 206 is in flow connection with the second fuel inlet 201 by means of a second fuel feed channel 212.
  • the fuel inlet is in flow communication with the source of a second fuel 20.
  • the second fuel feed channel 212 is provided with a second pressure accumulator space 214 between the second fuel gallery and the second fuel inlet 201 , preferably in a body of the injector.
  • the second fuel gallery 206 is therefore in flow connection with the second fuel inlet 201 via the second pressure accumulator space 214.
  • the second fuel feeding section may be designed so that it is capable of delivering fuel into a combustion chamber of the engine as an amount representing even up to 70-100% of the energy to run the engine at its design load.
  • the most important function of the second fuel is promoting or providing ignition of the first fuel, in which case it represents typically less than 10% of the total fuel energy brought into the cylinder.
  • the second fuel is used as the control fluid of the second valve 202.
  • the second fuel feeding section 200 utilizes the second fuel as the control fluid of the valve.
  • the control fluid return lines from both of the valves are combined to single outlet 122.
  • the pressurized working fluid and sealing fluid in the first injection valve 100 is the second fuel which is, however, fed to the first fuel injection valve 100 through a dedicated inlet 118.
  • the sealing fluid chamber 126 in the first fuel injection valve is in continuous flow connection with the inlet 118. This ensures that the pressure in the sealing fluid chamber is substantially adequate level and substantially free from pulsation.
  • a fuel inlet 102 and a fuel gallery 114 are provided to the injection valve.
  • the fuel gallery 114 is arranged in flow communication with the fuel inlet 102.
  • Fuel outlet 112, via which fuel is injected as a spray is arranged to opposite end of the injection valve 100.
  • the fuel outlet is arranged to the fuel gallery, the outlet may be provided with one or more injection orifices 112.1 , 112.2.
  • a valve needle 114 is arranged axially movably in the body to close or open the fuel outlet 112.
  • Desired cylinder-specific nominal maximum power for a cylinder where the fuel injection valve is intended to be used is determined, and the fuel outlet 112 is provided with area, which is 2 - 8,5 mm 2 /MW, wherein MW is cylinder-specific nominal maximum power, when in use with fuel which has its lower heating value lowest of the fuels intended and/or designed to be used in the engine. Specifically, MW is cylinder-specific nominal maximum power when in use with liquid fuel liquid fuel which has its lower heating value ⁇ 33 MJ/kg.

Landscapes

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

Abstract

Invention relates to a method of combusting first liquid fuel and a second liquid fuel, the first liquid fuel having its lower heating value less than the second liquid fuel, in the internal combustion piston engine, wherein - a first liquid fuel is injected into a cylinder of the engine as a main fuel which brings a major part of energy to the process, such that total amount of first liquid fuel delivered to the cylinder for one combustion stage is divided into at least two partial injections, wherein - the main injection of the first liquid fuel comprises 70-95 % of the total amount of the first liquid fuel, and - the start of main injection takes place earliest at 20 °CA before top dead center position of a piston in the cylinder, - a pre-injection of the first liquid fuel comprises 5-30% of the total amount of first liquid fuel, and wherein - the start of pre-injection takes place at 20-55 °CA before top dead center position of a piston in the cylinder, and the pre-injection is formed of one injection occurrence, and - a second liquid fuel is injected into the cylinder of the engine as fuel assisting compression ignition, such that start of injection of the second liquid fuel takes place at 1 - 23 °CA before start of injection of main injection of the first liquid fuel.

Description

Method of combusting a first and a second liquid fuel in an internal combustion piston engine
Technical field
The present invention relates to method of combusting first liquid fuel and a second liquid fuel in the internal combustion piston engine.
Background art
[001] There is a strong demand for decreasing emissions from internal combustion engines in the market, particularly decarbonization is of particular interest. An effective solution for reducing emissions and lowering operating costs of large internal combustion engines both in ships and at power plants are so called dual or even tri-fuel engines, which can be operated using fuel which do not contain carbon or contain less carbon as the traditionally used fossil fuel. These multi-fuel engines offer the flexibility to choose the most suitable fuel according to the availability and price of different fuels and/or emission limits that are in force in a certain place or at a certain time. For instance, a ship engine can be operated on non-carbon fuels in areas where strict emission limits are applied and on fossil fuel oil elsewhere.
[002] Traditionally when operating a large diesel or gas engine intended for a power production in a land-based power plant or in a marine vessel, fuel injection timing which ignites the fuel has commonly been considered to take place about at top dead center (TDC in the following) after compression stroke. For example, in diesel engine, LFO as a fuel, an injection may take place 25 “crank angle (CA in the following) before TDC to 5 “CA after TDC, and normally, the injection window being typically about 25 “CA long.
[003] When adopting the commonly known principles and experiences for the selection of timing and duration of fuel injection for low lower heating value fuels, these practices lead to necessity of providing larger injector for such fuels to maintain the timing and duration of the injection in the traditional ranges and resulting in corresponding power to the traditional fuels. That is because the narrow injection window and practical injection pressure require significant increase in the flow rate of fuel as a function of time to achieve the desired power per cylinder of the engine. It has been found that injecting such a large amount of fuel within a narrow window at TDC region results in a diffusion flame burning closer to the cylinder wall increasing the components thermal load.
[004] The great amount of fuel injected during compression stroke is prone to problems like increase in fuel slip and cylinder liner wetting.
[005] An object of the invention is to provide method of combusting a first liquid fuel and a second liquid fuel, the first liquid fuel having its lower heating value less than the second liquid fuel, in the internal combustion piston engine, which results in high performance and low emissions of the combustion.
Disclosure of the Invention
[006] Objects of the invention can be met substantially as is disclosed in the independent claims and in the other claims describing more details of different embodiments of the invention.
[007] According to an embodiment of the invention a method of combusting first liquid fuel and a second liquid fuel, the first liquid fuel having its lower heating value less than the second liquid fuel, in the internal combustion piston engine, comprises steps, such that a first liquid fuel is injected into a cylinder of the engine as a main fuel which brings a major part of energy to the process, such that total amount of first liquid fuel delivered to the cylinder for one combustion stage is divided into at least two partial injections, wherein o the main injection of the first liquid fuel comprises 70-95 % of the total amount of the first liquid fuel, and o the start of main injection takes place earliest at 20 °CA before top dead center position of a piston in the cylinder, o a pre-injection of the first liquid fuel comprises 5-30% of the total amount of first liquid fuel, and o the start of pre-injection takes place at 20-55 °CA before top dead center position of a piston in the cylinder, and the pre-injection is formed of one injection occurrence, and a second liquid fuel is injected into the cylinder of the engine as fuel assisting compression ignition, such that start of injection of the second liquid fuel takes place at 1 - 23 °CA before start of injection of main injection of the first liquid fuel.
[008] This way a remarkable improvement in cylinder component’s thermal load is achieved while still enabling the possibility to maintain engine output at desired level when combusting a low lower heat value fuel as a main fuel.
[009] According to an aspect of the invention the start the pre-injection of first liquid fuel takes place at 25-35 °CA before top dead center (bTDC) position, preferably at 25-30 °CA before top dead center position, which provides suitable circumstances in the cylinder for the first fuel to form a premixed mixture.
[0010] According to the invention the pre-injected portion of first fuel has adequate time to form a premixed air-fuel mixture, combustion of which in the combustion chamber after compression promoted ignition, takes place dominantly as premixed combustion. Fusing into the diffusive combustion of the main injection of the first fuel after compression ignition, the premixed combustion of the pre- injection portion of the first fuel ensures correctly phased pressure rise in the combustion chamber as well as high efficiency and low emissions of the engine.
[0011] According to an aspect of the invention start the main injection of first liquid fuel takes place at 10-0 °CA before top dead center position.
[0012] According to an aspect of the invention main injection of the first liquid fuel is formed of one injection occurrence.
[0013] According to an alternative aspect of the invention main injection of the first liquid fuel is formed of several injection occurrences, start of the first one of the several injection occurrences takes place earliest at 15 °CA bTDC.
[0014] According to an aspect of the invention second liquid fuel injection is formed of one injection occurrence and its duration is 2 to 6°CA. Preferably injection of the second liquid fuel ends before start of injection of the main injection of the first fuel, wherein start of injection of the second liquid fuel takes place at 1-5 °CA before start of injection of main injection of the first liquid fuel and duration of injection of the second fuel is 1 to 3°CA.
[0015] According to an aspect of the invention the main injection comprises 85- 90 % of the total amount of first liquid fuel, and the pre-injection comprises 10- 15% of the total amount of first liquid fuel.
[0016] According to an aspect of the invention the pre-injection comprises 10- 15% of the total amount of first liquid fuel and start of pre-injection takes place at 25-30 °CA bTDC.
[0017] According to an aspect of the invention the start the pre-injection of first liquid fuel takes place at 25-35 °CA before top dead center position, and the main injection comprises 85-90 % of the total amount of first liquid fuel, and the pre- injection comprises 10-15% of the total amount of first liquid fuel.
[0018] According to an aspect of the invention the start the pre-injection of first liquid fuel takes place at 25-30 °CA before top dead center position and the main injection comprises 85-90 % of the total amount of first liquid fuel, and the pre- injection comprises 10-15% of the total amount of first liquid fuel.
[0019] According to an aspect of the invention main injection of the first liquid fuel is formed of one injection occurrence and the main injection comprises 85- 90 % of the total amount of first liquid fuel, and the pre-injection comprises 10- 15% of the total amount of first liquid fuel.
[0020] According to an aspect of the invention main injection of the first liquid fuel is formed of one injection occurrence and the main injection comprises 85- 90 % of the total amount of first liquid fuel, and the pre-injection comprises 10- 15% of the total amount of first liquid fuel.
[0021] According to an aspect of the invention main injection of the first liquid fuel is formed of several injection occurrences, start of the first one of the several injection occurrences takes place earliest at 15 °CA bTDC and the main injection comprises 85-90 % of the total amount of first liquid fuel, and the pre-injection comprises 10-15% of the total amount of first liquid fuel.
[0022] According to an aspect of the invention first liquid fuel has its lower heating value < 33 MJ/kg and second liquid fuel has its lower heating value > 33MJ/kg.
[0023] According to an aspect of the invention the first liquid fuel comprises at least 51 % methanol, preferably is methanol, and start of injection of the second liquid fuel takes place at 1-3 °CA before start of injection of main injection of the first liquid fuel. Preferably the start of injection is 1-2 °CA before start of injection of main injection.
[0024] According to an aspect of the invention the first liquid fuel comprises at least 51 % methanol and injection pressure of the first liquid fuel is 0,8 MPa - 1 ,2 MPa.
[0025] According to an aspect of the invention the first liquid fuel comprises at least 51% methanol and start of injection of the main injection of the first fuel is dependent of engine load such that at loads greater than 50% of engine’s maximum nominal load, start of injection is delayed at least 5% or 1 °CA compared to start of injection at loads less than or equal to 50%.
[0026] This procedure minimises so called fuel slip.
[0027] The aspects above concerning the liquid fuel containing mostly methanol can be successfully used in any combination with each other to improve the operation with methanol.
[0028] According to an aspect of the invention the first liquid fuel comprises NH3 and start of injection or second liquid fuel takes place at 3-7 °CA before start of injection of main injection of the first liquid fuel. Preferably the start of injection is 4-5 °CA before start of injection of main injection.
[0029] According to an aspect of the invention the first liquid fuel comprises at least 51% NH3 and injection pressure of the first liquid fuel is 1 ,0 MPa - 1 ,7 MPa. [0030] According to an aspect of the invention the first liquid fuel comprises at least 51 % NH3 and start of injection of the main injection of the first fuel is dependent of engine load such that at loads outside a range of 25 to 60 % of engine’s maximum nominal load, start of injection is advanced 1 - 10 °CA compared to start of injection at loads inside the range.
[0031] This procedure minimises so called fuel slip.
[0032] The aspects above concerning the liquid fuel containing mostly ammonia can be successfully used in any combination with each other to improve the operation with ammonia.
[0033] According to an aspect of the invention start of main injection takes place between 10 - 0 °CA before top dead center position of a piston in the cylinder.
[0034] According to an aspect of the invention start of main injection of the first liquid fuel takes place before end of injection of the second liquid fuel.
[0035] According to an aspect of the invention a desired cylinder-specific nominal maximum power is determined or set for a cylinder of an engine in which the method is intended to be used, a first injection valve is provided for injecting at least the first fuel, the injection valve comprising
• a fuel inlet,
• a fuel gallery which is arranged in flow communication with the fuel inlet (102),
• a fuel outlet in the fuel gallery, the outlet comprising one or more injection orifices,
• a valve needle arranged to close or open the fuel outlet, and
• area of the fuel outlet is arranging to be 2 - 8,5 mm2/MW, wherein MW is the cylinder-specific nominal maximum power, when in use with the first fuel.
[0036] According to an aspect of the invention the method comprising determining or setting a desired cylinder-specific nominal maximum power for a cylinder of an engine in which the method is intended to be used, providing a first injection valve for injecting at least the first fuel, the injection valve comprising
• a fuel inlet,
• a fuel gallery which is arranged in flow communication with the fuel inlet, • a fuel outlet in the fuel gallery, the outlet comprising one or more injection orifices,
• a valve needle arranged to close or open the fuel outlet, and
• area of the fuel outlet is arranged to be 2 - 8,5 mm2/MW, wherein MW is the cylinder-specific nominal maximum power, when in use with the first fuel, and running the internal combustion engine alternatively using of the following operation modes:
A. a first operation mode during which method first liquid fuel and a second liquid fuel are combusted in the internal combustion piston engine, wherein: a first liquid fuel is injected using the first injection valve into a cylinder of the engine as a main fuel which brings a major part of energy to the process, such that total amount of first liquid fuel delivered to the cylinder for one combustion stage is divided into at least two partial injections, wherein o the main injection comprises 70-95 % of the total amount of the first liquid fuel, and o the start of main injection takes place earliest at 20 °CA before top dead center position of a piston in the cylinder, o a pre-injection comprises 5-30% of the total amount of first liquid fuel, and o the start of pre-injection takes place at 20-55 °CA before top dead center position of a piston in the cylinder, and the pre- injection is formed of one injection occurrence, a second liquid fuel is injected into the cylinder of the engine as fuel assisting compression ignition using a second fuel injection valve, such that start of injection of the second liquid fuel takes place at 1- 23 °CA before start of injection of main injection of the first liquid fuel, and
B. a second operation mode during which second liquid fuel is combusted as a main fuel by injecting a major portion of the second liquid fuel directly, as one injection occurrence, into the cylinder through the first fuel injection valve and second portion of the second liquid fuel through the second fuel injection valve as one injection occurrence and igniting the fuel by compression ignition.
[0037] The first fuel having its lower heating value lower than the second fuel is according to a preferred embodiment methanol, ammonia or a mixture thereof. Also, mixtures of methanol and light fuel oil or ammonia and light fuel oil has it lower heating value < 33 MJ/kg, when share of the light fuel oil is 50% or less.
[0038] Cylinder specific nominal maximum power means the power which engines manufacturer has set as maximum output power of a cylinder. The total output power of the engine is the sum of powers of individual cylinders. For example, a 6-cylinder engine has nominal maximum power of six times of the nominal power of a single cylinder (a power pack).
[0039] The present invention is particularly advantageous in large internal combustion piston engines running low or medium speed where the absolute time, as well as cylinder volumes for a single combustion cycle affect the combustion chemistry allowing different type of injection phasing than in smaller engines operating at higher rotational speed. Invention is applicable for use in addition to four stroke engines as well as in two stroke engines.
[0040] By means of the invention it is also possible to avoid or at least minimize a fuel slip i.e. escape of unburned fuel to the environment as well as undue cylinder liner wetting by injected fuel.
[0041] It has been discovered that combustion of both low heat value fuel and high heat value fuel using the direct injection method according to the invention is efficient and clean, and also provides equal cylinder-specific power in a medium-speed four-stroke engines with following particulars: rpm range: 300 to 1800 rpm injection pressure ranges o main fuel 600 to 2500 bar
LFO as main fuel bar for example 600 - 2300 bar
LHV as main fuel bar 600 - 2500 bar o pilot fuel 900 to 2500 bar, preferably higher than the main fuel pressure cylinder bores at least 135, preferably 150 mm - 700 mm single cylinder nominal power output: 80 to 2500 kW/cylinder
[0042] In this invention it has been surprisingly found, strongly against the dominant understanding among persons skilled in the art, that in the combustion of liquid fuels having substantially low lower heating value, the duration of the combustion process does not have the same relationship with the injection duration compared to that of traditional diesel engines operated with fuels like heavy, medium or even light fuel oils. In fact, it has been found that in combustion of low lower heating value fuels, particularly ammonia and methanol, duration of the combustion process is not directly related to the duration of fuel injection period.
[0043] This leads to new solutions where the injection duration of such fuels can be expanded outside traditional ranges without leading to degradation in the combustion efficient or emission levels. This way it possible to use same, smaller size of injectors for different fuels by suitably setting the injection period and without need of compensating operation via significantly different injection pressures.
[0044] In this context the term “main fuel” means fuel which brings the majority of the energy to a combustion chamber. The presented crank angles in this application refer to control values for actuating a fuel injector.
[0045] The exemplary embodiments of the invention presented in this patent application are not to be interpreted to pose limitations to the applicability of the appended claims. The verb “to comprise” is used in this patent application as an open limitation that does not exclude the existence of also unrecited features. The features recited in dependent claims are mutually freely combinable unless otherwise explicitly stated. The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. Brief Description of Drawings
[0046] In the following, the invention will be described with reference to the accompanying exemplary, schematic drawings, in which
Figure 1 illustrates a fuel injection scheme according to an embodiment of the invention, and
Figure 2 illustrates a fuel injector system according to an embodiment of the invention.
Detailed Description of Drawings
[0047] A method of combusting first liquid fuel and a second liquid fuel according to an aspect of the invention is explained referring to the Figure 1 . Method relates to so called direct injection, which refers to injecting fuel directly to combustion chamber of a cylinder when the piston is approaching to or is approximately at its top dead center (TDC) position after compression stroke, in a four-stroke engine. In the method a predetermined amount of a first fuel and a second fuel is injected into the cylinder for each combustion stage. The first liquid fuel is injected into a cylinder of the engine as a main fuel which brings a major part of energy to the combustion process. The first liquid fuel has its lower heating value less than the second liquid fuel. According to an aspect of the invention the first fuel has its lower heating value < 33 MJ/kg, and the second fuel has its lower heating value > 33MJ/kg, preferably > 42MJ/kg. As it becomes clear from the figure 1 , the total amount of first liquid fuel delivered to the cylinder for one combustion stage is divided into two partial injection stages, the first one being a pre-injection 12 and the second one being a main injection 10. Figure 1 discloses on its horizontal axis a crank angle of preferred range of start of injection and on its vertical axis a relative quantity of the fuel. Each area borders a range within which operation point (fuel relative quantity and start of injection of fuel) of the injection is located. The main injection 10 starts at earliest at 10 °CA bTDC and the range of start of injection is between 10°CA bTDC to TDC and the main injection comprises 70-95% of the total amount of the first liquid fuel. Respectively a pre-injec- tion starts at earlies at 55°CA bTDC and its range within which the injection may be started is 35°CA, 55°CA bTDC to 20°CA bTDC. The pre-injection comprises 5-30% of the total amount of first liquid fuel.
[0048] Additionally, an injection of the second fuel 14 is taken place, the injection starting at 1-5 °CA before start of injection of the main injection 10 of the first fuel. Amount of the injection of the second fuel corresponds to 3 - 10 % of energy brough by the first fuel into the combustion process.
[0049] In the method the pre-ignition portion of the first fuel forms a pre-mixed charge in the combustion chamber and is ignited and combusted as pre-mixed combustion. Injection of second fuel before injection of the mail fuel ensures compression ignition and combustion of the pre-mixed charge and diffusion combustion of the main fuel. Thus, first fuel is combusted partly i.e. the pre-injection part, as pre-mixed combustion and partly i.e. the main injection part, as diffuse combustion. The pre-injection is formed of one injection occurrence, i.e. not as a so- called split injection. Typically, the quantity of the second fuel assisting compression ignition is such that it promotes and ensures compression ignition of the main fuel by affecting circumstances inside the main combustion chamber. The ignition takes place when the pressure, temperatures, fuel mixture and existence of chemically active species (radicals) is suitable to become ignited and support premixed and diffusive combustion.
[0050] The invention makes it possible to combust a liquid fuel which has substantially low lower heat value i.e. the lower heat value being < 33 MJ/kg as the first fuel, with assistance of a second fuel having its lower heat value > 33MJ/kg, preferably > 42MJ/kg, and still obtain cylinder specific maximum nominal power which is comparable to e.g. combustion of diesel fuel in corresponding cylinder. Cylinder specific nominal maximum power means the power which engines manufacturer has set as maximum output power of a cylinder. The total output power of the engine is the sum of powers of individual cylinders. For example, a 6-cyl- inder engine has nominal maximum power of six times of the nominal power of a single cylinder (a power pack).
[0051] Duration of injection of the second fuel is selected in the method such that start of main injection 10 of the first liquid fuel takes place before end of injection of the second liquid fuel. This ensures reliable compression ignition of the fuel admitted to the combustion chamber during the main injection.
[0052] Figure 1 depicts by the hatched area 10’, 12’, an aspect of the invention with a special range of pre- and main injection of the first fuel according to an aspect of the invention. Thus, the special range of the start the pre-injection of first liquid fuel takes place at 25-35 °CA bTDC and its proportion the total amount of first liquid fuel is 10-15 %. The main injection of the first fuel comprises 85-90 % of the total amount of first liquid fuel according to the aspect of the invention.
[0053] According to a first embodiment of the invention the first fuel is methanol, and the second fuel is diesel fuel or a like, such as light fuel oil or marine diesel oil.
[0054] According to the first embodiment of the invention the method comprises a feature that start of injection of the second liquid fuel takes place at 1-3 °CA before start of injection of main injection of the first liquid fuel. That is, when particularly methanol is used as the first fuel the injection of the compression ignition assisting fuel needs to be injected closer to the start of ignition of the main fuel.
[0055] According to a second embodiment of the invention the first fuel is ammonia, and the second fuel is diesel fuel or a like, such as light fuel oil or marine diesel oil.
[0056] According to the second embodiment of the invention the method comprises a feature that start of injection of the second liquid fuel takes place at 3-5 °CA before start of injection of main injection of the first liquid fuel. That is, when particularly ammonia is used as the first fuel the injection of the compression ignition assisting fuel needs to be injected little earlier to the start of ignition of the main fuel.
[0057] Figure 2 discloses a fuel injector system 10 configured to practise the method according to the engine, for one cylinder. The cylinder is provided with the first injection valve 100 and a second liquid fuel injection valve 200. The first injection valve 100 is configured to inject the main fuel and the second injection valve 200 is configured to inject fuel assisting compression ignition, at least during a normal operation with the first fuel. The first injection valve 100 and the second liquid fuel injection valve 200 may be arranged to separate bodies or in a common injector body, which is preferable because in that way adapting the injection valve to a cylinder head is easier.
[0058] The first injection valve 100 comprises a fuel inlet 102 and a fuel gallery 104, which is arranged in flow communication with the fuel inlet 102 via a flow path 106 arranged to an injector body (not shown in the figure 2). The flow path is preferably provided with a so-called flow fuse 108, which prevents excess flow of the fuel in case of malfunction of the injection valve 100. As a preferred feature, the flow path 106 is provided with a pressure accumulator 110 arranged between the fuel gallery 104 and the fuel inlet 102. The pressure accumulator 110 is also arranged between the fuel inlet 102 and the flow fuse 108, such that the volume of the flow channel downstream (in normal operation fuel flow direction) to the flow fuel is smaller and possible leakage fuel amount is thus smaller in case of malfunction. The pressure accumulator serves only for the first injection valve 100 and therefore fuel delivery during injection is ensured. The inlet 102 of the direct injection valve 100 is arranged in controllable flow connection with a source of a first fuel 16 and a source of a second fuel 20, which is shown only schematically in the figure 2. This way the fuel which is injected by the direct injection valve 100 may, if so desired, be selected between the first fuel and the second fuel, or even a blend of the first fuel and the second fuel may be used.
[0059] The first injection valve 100 is provided with a valve needle 114 which is arranged to close or open a fuel outlet 112 by its axial movement. The valve needle 114 is controlled by hydraulic control system 116. The hydraulic control system may be realized in various manners making use of a principle of creating a biasing force against force created by injection pressure of the fuel. In the embodiment of the figure 1 the hydraulic control system is provided with an inlet 118 of pressurized working fluid via which the pressurized working fluid is led to needle housing at the end of the needle opposite to the fuel outlet 112. There is a pressure chamber 124 which is bordered by an end of the needle 114 such that the pressure of the working fluid causes a force to the needle 114. Outlet flow channel 122 of the hydraulic control system 116 is provided with a valve 120 which, when opened, reliefs the pressure from the chamber 124 which causes the needle to move, upwards in the figure, opening the fuel outlet 112. When the valve 120 is closed pressure is build up in the chamber 124 urging the needle 114 back to closed position. The working fluid also fills a sealing fluid chamber 126 around upper part of the needle 114 at high pressure than fuel injection pressure so as to prevent the first fuel flowing into hydraulic control system 116 and mixing with the working fluid.
[0060] There is also a fuel outlet 112 in the valve arranged to open into the fuel gallery 104, which outlet may comprise one or more injection orifices 112.1 , 112.2. As it becomes clear from the enlarged section of the valve, the orifice(s) may have circular cross section with a diameter, which defines geometrical cross- sectional area of the orifice. The area A of the outlet 112, in case there are several orifices, is a sum of the individual orifice areas Ao i.e. A =£i Ao w.
[0061] The total area A of the fuel outlet is dimensioned such that it is 2 - 8,5 mm2 I WN, wherein MW is cylinder specific nominal maximum power output, which is determined based on an engine’s specification to which the fuel injection valve is intended to be used. The first injection valve 100 is a multifuel fuel injection arrangement which is dimensioned to produce, in practical circumstances, substantially equal nominal maximum power per cylinder of the engine by combustion of any one of the used fuels. In practical circumstances usual there are two different liquid fuels running the engine. The fuel outlet area in the injection valve is dimensioned based on, using the specific correlation of intended maximum nominal power per cylinder, fuel which as the lowest heating value of the fuels intended to be used which ensures that the injection valve is capable of inject adequate amounts of fuel when in use with any one of the intended fuels, both of low lower heat value and high lower heat value fuels. According to the invention the area of the fuel outlet 112 is designed based on cylinder specific nominal maximum power, when in use with fuel which has its lower heating value lowest of the different fuels. More precisely, the area A of the fuel outlet 112 is 2 - 8,5 mm2/MW, wherein MW is cylinder-specific nominal maximum power, when in use with fuel which has its lower heating value < 33 MJ/kg. Fuel pressure is taken into account to dimensioning of the area A such that injection pressure is 600-2500 bar. The pressure range covers different possible variations in fuel viscosity and when in use, suitable amount of fuel in each charged can be fine-tuned by total injection duration. In a multifuel engine, the fuel pressures for the different fuels may be selected close to each other so that the15ifferrent fuels can be more easily directed into the same direct injection valve operating as a multifuel injection valve. One of the fuel pressures, for example, that of second fuel (e.g. LFO) in the source of a second fuel 20 may be selected to be a bit higher than that of the first fuel (a fuel with low lower heating value) so that the second fuel can be used to displace or flush parts of the fuel system common for both fuels when switching between fuels. This may be important for safety and service points of view as some of the fuel having low lower heating value, such as for example ammonia or methanol, have toxic properties.
[0062] For example, an engine is intended be operated with at least two fuels, one of which has lower heating value than the other, and the direct injection valve is designed based on the fuel which has its lower heating value lowest of the first fuel and the second fuel. When applied to smaller bore diameter engine, such as 200 mm, in which case the cylinder-specific nominal maximum power is determined to be 150 kW, the area A will be 0,300 - 1 ,275 mm2. Respectively, when applied to a large bore diameter engine, such as 640 mm, in which case the cylinder-specific nominal maximum power is determined to be 1300 kW, the area A will be less than 2,60 - 11 ,05 mm2. It is preferable that the area is designed near to upper end of obtained range of value A of the area to avoid unnecessarily long injection periods, however some compromise may be acceptable in practice as long as it does not lead to degradation of the combustion process.
[0063] In the figure 2 the second fuel injection valve 200 comprises a needle 204 for administering second fuel into a combustion chamber of the engine. A second fuel gallery 206 is in flow connection with the second fuel inlet 201 by means of a second fuel feed channel 212. The fuel inlet is in flow communication with the source of a second fuel 20. The second fuel feed channel 212 is provided with a second pressure accumulator space 214 between the second fuel gallery and the second fuel inlet 201 , preferably in a body of the injector. The second fuel gallery 206 is therefore in flow connection with the second fuel inlet 201 via the second pressure accumulator space 214. There is also a hydraulically operated second valve control section 210 in the fuel injector unit 10 arranged at an end, opposite to a needle end, of the second fuel injection valve needle 204. The second fuel feeding section may be designed so that it is capable of delivering fuel into a combustion chamber of the engine as an amount representing even up to 70-100% of the energy to run the engine at its design load. However, the most important function of the second fuel is promoting or providing ignition of the first fuel, in which case it represents typically less than 10% of the total fuel energy brought into the cylinder.
[0064] The second fuel is used as the control fluid of the second valve 202. In other words, the second fuel feeding section 200 utilizes the second fuel as the control fluid of the valve. As it becomes clear from the figure 2 the control fluid return lines from both of the valves are combined to single outlet 122. This means in that the pressurized working fluid and sealing fluid in the first injection valve 100 is the second fuel which is, however, fed to the first fuel injection valve 100 through a dedicated inlet 118. This way the working fluid led to the first valve may be at different pressure compared to the second fuel. This also provides independent control of the pressure. The sealing fluid chamber 126 in the first fuel injection valve is in continuous flow connection with the inlet 118. This ensures that the pressure in the sealing fluid chamber is substantially adequate level and substantially free from pulsation.
[0065] When designing and/or manufacturing the fuel injection valve according to an embodiment of the invention a fuel inlet 102 and a fuel gallery 114 are provided to the injection valve. The fuel gallery 114 is arranged in flow communication with the fuel inlet 102. Fuel outlet 112, via which fuel is injected as a spray is arranged to opposite end of the injection valve 100. The fuel outlet is arranged to the fuel gallery, the outlet may be provided with one or more injection orifices 112.1 , 112.2. A valve needle 114 is arranged axially movably in the body to close or open the fuel outlet 112. Desired cylinder-specific nominal maximum power for a cylinder where the fuel injection valve is intended to be used is determined, and the fuel outlet 112 is provided with area, which is 2 - 8,5 mm2/MW, wherein MW is cylinder-specific nominal maximum power, when in use with fuel which has its lower heating value lowest of the fuels intended and/or designed to be used in the engine. Specifically, MW is cylinder-specific nominal maximum power when in use with liquid fuel liquid fuel which has its lower heating value < 33 MJ/kg. [0066] While the invention has been described herein by way of examples in connection with what are, at present, considered to be the most preferred embodiments, it is obvious to the skilled person that, along with the technical progress, the basic idea of the invention can be implemented in many ways. The invention and its embodiments are thus not limited to the examples and samples described above but they may vary within the contents of patent claims and their legal equivalents. The details mentioned in connection with any embodiment above may be used in connection with another embodiment when such combination is technically feasible.

Claims

Claims
1. A method of combusting first liquid fuel and a second liquid fuel, the first liquid fuel having its lower heating value less than the second liquid fuel, in the internal combustion piston engine, wherein a first liquid fuel is injected into a cylinder of the engine as a main fuel which brings a major part of energy to the process, such that total amount of first liquid fuel delivered to the cylinder for one combustion stage is divided into at least two partial injections, wherein o the main injection of the first liquid fuel comprises 70-95 % of the total amount of the first liquid fuel, and o the start of main injection takes place earliest at 20 °CA before top dead center position of a piston in the cylinder, o a pre-injection of the first liquid fuel comprises 5-30% of the total amount of first liquid fuel, and wherein o the start of pre-injection takes place at 20-55 °CA before top dead center position of a piston in the cylinder, and the pre-injection is formed of one injection occurrence, and a second liquid fuel is injected into the cylinder of the engine as fuel assisting compression ignition, such that o Start of injection of the second liquid fuel takes place at 1 - 23 °CA before start of injection of main injection of the first liquid fuel.
2. Method according to claim 1 , characterized in that the start the pre-injection of first liquid fuel takes place at 25-35 °CA before top dead center position.
3. Method according to claim 2, characterized in that the start the pre-injection of first liquid fuel takes place at 25-30 °CA before top dead center position.
4. Method according to claim 1 , characterized in that the start the main injection of first liquid fuel takes place at 10-0 °CA before top dead center position.
5. Method according to claim 1 , characterized in that the main injection of the first liquid fuel is formed of one injection occurrence.
6. Method according to claim 1 , characterized in that the main injection of the first liquid fuel is formed of several injection occurrences, start of the first one of the several injection occurrences takes place earliest at 15 °CA bTDC.
7. Method according to claim 1 , characterized in that the second liquid fuel injection is formed of one injection occurrence and its duration is 2 to 6°CA.
8. Method according to anyone of the preceding claim 1 to 7, characterized in that the main injection comprises 85-90 % of the total amount of first liquid fuel, and the pre-injection comprises 10-15% of the total amount of first liquid fuel.
9. Method according to anyone of the preceding claims 1 to 9, characterized in that the first liquid fuel comprises at least 51 % methanol.
10. Method according to claim 10, characterized in that start of injection of the second liquid fuel takes place at 1-3 °CA before start of injection of main injection of the first liquid fuel.
11. Method according to claim 10, characterized in that injection pressure of the first liquid fuel is 0,8 MPa - 1 ,2 MPa.
12. Method according to claim 10, characterized in that start of injection of the main injection of the first fuel is dependent of engine load such that at loads greater than 50% of engine’s maximum nominal load, start of injection is delayed at least 5% or 1 °CA compared to start of injection at loads less than or equal to 50%.
13. Method according to anyone of the preceding claims 10 to 13, characterized in that the first liquid fuel is methanol.
14. Method according to anyone of the preceding claims 1 to 9, characterized in that the first liquid fuel comprises at least 51 % NH3.
15. Method according to claim 15, characterized in that start of injection or second liquid fuel takes place at 3-7 °CA before start of injection of main injection of the first liquid fuel.
16. Method according to claim 15, characterized in that injection pressure of the first liquid fuel is 1 ,0 MPa - 1 ,7 MPa.
17. Method according to claim 10, characterized in that start of injection of the main injection of the first fuel is dependent of engine load such that at loads outside a range of 25 to 60 % of engine’s maximum nominal load, start of injection is advanced 1-10 °CA compared to start of injection at loads inside the range.
18. Method according to anyone of the preceding claims 15 to 18, characterized in that the first liquid fuel is NH3.
19. Method according to claim 1 , characterized in that start injection of main injection of the first liquid fuel takes place before end of injection of the second liquid fuel.
20. A method according to anyone of the preceding claims, characterized in that a desired cylinder-specific nominal maximum power is determined or set for a cylinder of an engine in which the method is intended to be used, a first injection valve is provided for injecting at least the first fuel, the injection valve comprising
• a fuel inlet (102),
• a fuel gallery (104) which is arranged in flow communication with the fuel inlet (102),
• a fuel outlet (112) in the fuel gallery (104), the outlet (112) comprising one or more injection orifices,
• a valve needle (114) arranged to close or open the fuel outlet (112), and
• area of the fuel outlet (112) is arranged to be 2 - 8,5 mm2/MW, wherein MW is the cylinder-specific nominal maximum power, when in use with the first fuel.
21 . Method according to claim 20, characterized in that the method comprising running the internal combustion engine alternatively using of the following operation modes:
A. A first operation mode during which first liquid fuel and a second liquid fuel are combusted in the internal combustion piston engine, wherein a first liquid fuel is injected using the first injection valve into a cylinder of the engine as a main fuel which brings a major part of energy to the process, such that total amount of first liquid fuel delivered to the cylinder for one combustion stage is divided into at least two partial injections, wherein o the main injection of the first liquid fuel comprises 70-95 % of the total amount of the first liquid fuel, and o the start of main injection takes place earliest at 20 °CA before top dead center position of a piston in the cylinder, o a pre-injection of the first liquid fuel comprises 5-30% of the total amount of first liquid fuel, and wherein o the start of pre-injection takes place at 20-55 °CA before top dead center position of a piston in the cylinder, and the pre- injection is formed of one injection occurrence, and a second liquid fuel is injected into the cylinder of the engine as fuel assisting compression ignition, using a second fuel injection valve such that o Start of injection of the second liquid fuel takes place at 1 - 23 °CA before start of injection of main injection of the first liquid fuel, and
B. A second operation mode during which second liquid fuel is combusted as a main fuel by injecting a major portion of the second liquid fuel directly, as one injection occurrence, into the cylinder through the first fuel injection valve and second portion of the second liquid fuel through the second fuel injection valve, as one injection occurrence and igniting the fuel by compression ignition.
PCT/EP2024/054671 2023-11-07 2024-02-23 Method of combusting a first and a second liquid fuel in an internal combustion piston engine Pending WO2025098645A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EPPCT/EP2023/080970 2023-11-07
PCT/EP2023/080970 WO2025098592A1 (en) 2023-11-07 2023-11-07 Direct injection valve, method of manufacturing a direct injection valve, internal combustion piston engine, method of operating an internal combustion piston engine and a computer control system for operating an internal combustion piston engine

Publications (1)

Publication Number Publication Date
WO2025098645A1 true WO2025098645A1 (en) 2025-05-15

Family

ID=88731369

Family Applications (3)

Application Number Title Priority Date Filing Date
PCT/EP2023/080970 Pending WO2025098592A1 (en) 2023-11-07 2023-11-07 Direct injection valve, method of manufacturing a direct injection valve, internal combustion piston engine, method of operating an internal combustion piston engine and a computer control system for operating an internal combustion piston engine
PCT/EP2024/052292 Pending WO2025098644A1 (en) 2023-11-07 2024-01-31 A fuel feeding system for feeding liquid fuels into two or more cylinders of an internal combustion piston engine, an internal combustion piston engine and a method of operating an internal combustion engine
PCT/EP2024/054671 Pending WO2025098645A1 (en) 2023-11-07 2024-02-23 Method of combusting a first and a second liquid fuel in an internal combustion piston engine

Family Applications Before (2)

Application Number Title Priority Date Filing Date
PCT/EP2023/080970 Pending WO2025098592A1 (en) 2023-11-07 2023-11-07 Direct injection valve, method of manufacturing a direct injection valve, internal combustion piston engine, method of operating an internal combustion piston engine and a computer control system for operating an internal combustion piston engine
PCT/EP2024/052292 Pending WO2025098644A1 (en) 2023-11-07 2024-01-31 A fuel feeding system for feeding liquid fuels into two or more cylinders of an internal combustion piston engine, an internal combustion piston engine and a method of operating an internal combustion engine

Country Status (1)

Country Link
WO (3) WO2025098592A1 (en)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2001059280A1 (en) * 2000-02-11 2001-08-16 Westport Research Inc. Method and apparatus for dual fuel injection into an internal combustion engine
WO2015044501A1 (en) * 2013-09-25 2015-04-02 Wärtsilä Finland Oy Method for operating piston engine and piston engine
CN115596561A (en) * 2022-10-14 2023-01-13 东风商用车有限公司（Cn） Injection control method and combustion system of diesel ignition high pressure direct injection liquid ammonia internal combustion engine
CN116122974A (en) * 2023-02-09 2023-05-16 哈尔滨工程大学 Combustion system and combustion method of an in-cylinder direct-injection ammonia-diesel dual-fuel engine

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009138580A (en) * 2007-12-05 2009-06-25 Denso Corp Fuel injection valve and fuel injection device with the same
US8590510B2 (en) * 2010-08-24 2013-11-26 Ford Global Technologies, Llc Fuel system for a multi-fuel engine
FI123513B (en) * 2010-12-02 2013-06-14 Waertsilae Finland Oy Fuel supply unit, method for operating it and combustion engine
DE102015203607B4 (en) 2015-02-27 2019-12-19 Mtu Friedrichshafen Gmbh Internal combustion engine and method for operating an internal combustion engine
US10030610B2 (en) * 2015-03-20 2018-07-24 Progress Rail Locomotive Inc. Fuel system for an engine
US9995261B2 (en) * 2015-04-17 2018-06-12 Caterpillar Inc. Dynamic seal for fuel injector needle check
US11454189B2 (en) * 2015-06-29 2022-09-27 Ford Global Technologies, Llc Methods and systems for port fuel injection control
CN106762276A (en) * 2017-01-05 2017-05-31 江苏大学 A kind of new dual fuel injector of cavitation prevention and common rail fuel system
EP3434874A1 (en) * 2017-07-27 2019-01-30 Winterthur Gas & Diesel AG Method for operating a large diesel engine and large diesel engine

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2001059280A1 (en) * 2000-02-11 2001-08-16 Westport Research Inc. Method and apparatus for dual fuel injection into an internal combustion engine
WO2015044501A1 (en) * 2013-09-25 2015-04-02 Wärtsilä Finland Oy Method for operating piston engine and piston engine
CN115596561A (en) * 2022-10-14 2023-01-13 东风商用车有限公司（Cn） Injection control method and combustion system of diesel ignition high pressure direct injection liquid ammonia internal combustion engine
CN116122974A (en) * 2023-02-09 2023-05-16 哈尔滨工程大学 Combustion system and combustion method of an in-cylinder direct-injection ammonia-diesel dual-fuel engine

Also Published As

Publication number Publication date
WO2025098644A1 (en) 2025-05-15
WO2025098592A1 (en) 2025-05-15

Similar Documents

Publication Publication Date Title
AU2017200457B2 (en) Engine and method of operating engine
CN105822460B (en) Gas supply and ignition device for gas engine
KR101931840B1 (en) A two-stroke internal combustion engine, method operating a two-stroke internal combustion engine and method of converting a two-stroke engine
US6659071B2 (en) Internal combustion engine operable in PCCI mode with early control injection and method of operation
FI106884B (en) Method of introducing a main fuel and auxiliary fuel into an internal combustion engine and internal combustion engine
JP4466616B2 (en) Multi-fuel internal combustion engine
KR101990766B1 (en) For operating a piston engine in gas mode and piston engine
WO2003056159A1 (en) Dual fuel engine
FI124730B (en) Method of operating a piston motor and piston motor
KR20160036478A (en) Turbulent jet ignition pre-chamber combustion system for spark ignition engines
JP5922830B1 (en) Gas engine
KR20120058502A (en) Method for operating an internal combustion engine
JP7745964B2 (en) Dual-fuel engine fuel injector, dual-fuel engine, and method for operating a dual-fuel engine
CN114729604A (en) Method and gaseous fuel injection unit for operating an internal combustion engine
JP2009138568A (en) Internal combustion engine
WO2025098645A1 (en) Method of combusting a first and a second liquid fuel in an internal combustion piston engine
JP4386781B2 (en) engine
JP3617252B2 (en) Compression ignition engine
GB2311327A (en) Combined fuel injector and spark plug arrangement in an engine cylinder
US11359590B1 (en) Igniter for dual fuel engine having liquid fuel outlet checks and spark ignition source
JP2021188569A (en) Internal combustion engine using hydrogen fuel
US20250172104A1 (en) Apparatus and method for managing autoignition in an in-cylinder injector and combustion chamber of an internal combustion engine
JP2000064838A (en) Pilot ignition gas engine
JP2004092574A (en) Gas engine equipped with auxiliary scavenging device
JPH07189848A (en) Combustion method for internal combustion engine

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 24706458

Country of ref document: EP

Kind code of ref document: A1