CN117514531A - Large-cylinder-diameter ship low-speed machine and injection control method thereof - Google Patents

Large-cylinder-diameter ship low-speed machine and injection control method thereof Download PDF

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Publication number
CN117514531A
CN117514531A CN202311687950.1A CN202311687950A CN117514531A CN 117514531 A CN117514531 A CN 117514531A CN 202311687950 A CN202311687950 A CN 202311687950A CN 117514531 A CN117514531 A CN 117514531A
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China
Prior art keywords
hydrogen
liquid ammonia
fuel
input
injection
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CN202311687950.1A
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Chinese (zh)
Inventor
王洋
马炳成
张凯
刘龙
李钰宁
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Harbin Engineering University
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Harbin Engineering University
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Priority to CN202311687950.1A priority Critical patent/CN117514531A/en
Publication of CN117514531A publication Critical patent/CN117514531A/en
Pending legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M21/00—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form
    • F02M21/02—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form for gaseous fuels
    • F02M21/0203—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form for gaseous fuels characterised by the type of gaseous fuel
    • F02M21/0206—Non-hydrocarbon fuels, e.g. hydrogen, ammonia or carbon monoxide
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D19/00—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
    • F02D19/06—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures peculiar to engines working with pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed
    • F02D19/0639—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures peculiar to engines working with pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed characterised by the type of fuels
    • F02D19/0642—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures peculiar to engines working with pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed characterised by the type of fuels at least one fuel being gaseous, the other fuels being gaseous or liquid at standard conditions
    • F02D19/0644—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures peculiar to engines working with pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed characterised by the type of fuels at least one fuel being gaseous, the other fuels being gaseous or liquid at standard conditions the gaseous fuel being hydrogen, ammonia or carbon monoxide
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • 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
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M21/00—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form
    • F02M21/02—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form for gaseous fuels
    • F02M21/0218—Details on the gaseous fuel supply system, e.g. tanks, valves, pipes, pumps, rails, injectors or mixers
    • F02M21/0248—Injectors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M21/00—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form
    • F02M21/02—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form for gaseous fuels
    • F02M21/0218—Details on the gaseous fuel supply system, e.g. tanks, valves, pipes, pumps, rails, injectors or mixers
    • F02M21/0248—Injectors
    • F02M21/0257—Details of the valve closing elements, e.g. valve seats, stems or arrangement of flow passages
    • F02M21/026—Lift valves, i.e. stem operated valves
    • F02M21/0263—Inwardly opening single or multi nozzle valves, e.g. needle valves
    • 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
    • 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)
  • Oil, Petroleum & Natural Gas (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Fuel-Injection Apparatus (AREA)
  • Output Control And Ontrol Of Special Type Engine (AREA)

Abstract

The invention discloses a large-cylinder-diameter ship low-speed machine which comprises a dual-fuel coaxial injection system and a reforming system, wherein liquid ammonia and hydrogen-rich fuel are provided for the dual-fuel coaxial injection system through a liquid ammonia branch and a hydrogen reforming branch. The dual-fuel coaxial injection system comprises a mounting sleeve, a shell, an oil nozzle, an input liquid ammonia channel and an input hydrogen pipeline which are coaxially arranged, wherein the top end of the input liquid ammonia channel is communicated with a liquid ammonia inlet, the tail end of the input liquid ammonia channel is communicated with a liquid ammonia oil injection hole, the top end of the input hydrogen pipeline is communicated with a hydrogen inlet, and the tail end of the input hydrogen pipeline is communicated with a hydrogen injection hole; the installation sleeve, the shell and the cavity formed in the oil nozzle are internally provided with a piston and a needle valve assembly, and the liquid ammonia input channel and the hydrogen input pipeline are coaxially arranged in the shell and are respectively positioned at two sides of the cavity; the needle valve assembly is used for communicating/blocking the input liquid ammonia channel and the input hydrogen pipeline, and when the needle valve assembly moves upwards, the needle valve assembly is respectively communicated with the input liquid ammonia channel and the input hydrogen pipeline, so that liquid ammonia and hydrogen-rich fuel flow into corresponding injection holes.

Description

Large-cylinder-diameter ship low-speed machine and injection control method thereof
Technical Field
The invention belongs to the field of combustion optimization of internal combustion engines, and particularly relates to a large-cylinder-diameter ship low-speed engine capable of realizing coaxial injection of liquid ammonia and hydrogen-rich fuel and an injection control method thereof.
Background
The low-speed machine for the large-cylinder-diameter ship has been widely used as a host machine in large ships due to the advantages of high power, high reliability, excellent economy and the like. Both the low speed machine and the high speed machine mix the fuel and the air by burning, and burst flame in the combustion chamber to push the piston to move so as to transfer the rotating force to the shaft. The difference is that the low-speed engine adopts the design of long stroke and small cylinder diameter, so that the piston stroke is longer, and the peripheral speed of the engine rotation is also reduced.
In a fuel engine, a fuel injector injects fuel into an intake manifold or cylinder in accordance with injection timing and pulse width calculated by an engine ECU. The atomized fuel forms an oil-gas mixture after air mixing, which combusts and performs work in the cylinder of the engine to achieve driving of the engine. The marine gas fuel engine adopts dual fuel to inject mostly, and traditional fuel injector is single fuel injector mostly, can't inject different kinds of fuel in the jar and form active layering and reduce the burning rate. Thus, conventional injectors, in combination with dual fuel or other injection strategies, must be provided with multiple injectors in the engine cylinder, which can undoubtedly increase the complexity of the marine engine fuel injection apparatus. The dual-fuel oil sprayer can overcome the defects, and can reduce emission on the basis of obtaining high efficiency by combining clean energy such as ammonia and hydrogen. The prior dual fuel injector structure is generally a coaxial injection structure and a multi-shaft injection structure, the multi-shaft injection structure is complex, the device volume is larger, and the coaxial injection structure is simple and easy to realize. And ammonia reforming hydrogen production systems are well-established in the prior art. Ammonia is one of the most ideal "zero carbon" fuels for ships and has found wide application in the field of ships, but pure ammonia combustion requires higher ignition energy and has a low combustion speed. Hydrogen fuel is similar to ammonia in that it contains neither carbon nor sulfur. The reserve quantity of hydrogen in the world is sufficient, and the hydrogen is a good clean energy source, but the hydrogen has the characteristics of low energy density, low ignition energy, low flame propagation speed, easy leakage, easy diffusion, inflammability and explosiveness and the like, the safety of the hydrogen in transportation and storage is seriously restricted, the liquid hydrogen has the characteristic of ultralow temperature, the risk of application on a ship is higher, and the hydrogen preparation by using a renewable energy system is a good choice. At the same mass, the volume of the liquid ammonia is about 1/800 of that of the ammonia, so that the ship is more suitable for transporting the liquid ammonia. The ammonia is used as a hydrogen storage substance, has the advantages of high unit heat value, convenient storage and transportation, low cost, easy obtainment, no generation of harmful substances and greenhouse gases by complete combustion, and the like, so that the ammonia reforming hydrogen production system can be more convenient for the use of the marine engine for shipping, and the ammonia hydrogen blending combustion can well overcome the defects.
Disclosure of Invention
The invention aims to overcome the defects in the prior art, and provides a large-cylinder-diameter ship low-speed machine which comprises a dual-fuel coaxial injection system capable of coaxially injecting liquid ammonia and hydrogen-rich fuel, wherein a liquid ammonia channel and a hydrogen pipeline of the dual-fuel coaxial injection system are axially parallel to the central axes of a mounting cavity and a piston cavity, and can coaxially inject the liquid ammonia and the hydrogen-rich fuel in parallel; and the reforming system of the ship low-speed machine utilizes single ammonia fuel to provide liquid ammonia and hydrogen-rich fuel, so that the engine can realize dual-fuel continuous injection and dual-fuel coaxial injection.
The first aspect of the invention is to provide a large-cylinder-diameter ship low-speed machine, which comprises a dual-fuel coaxial injection system and a reforming system, wherein the dual-fuel coaxial injection system is arranged on a cylinder cover; the reforming system comprises a liquid ammonia branch and a hydrogen reforming branch; the liquid ammonia branch comprises an ammonia storage tank, a flow controller and a liquid ammonia inlet of the dual-fuel coaxial injection system which are sequentially connected through a pipeline; the hydrogen reforming branch comprises an ammonia storage tank, a reformer, an intercooler, a pressurizing pump, a regulating valve and a hydrogen inlet of the dual-fuel coaxial injection system which are sequentially connected through pipelines;
the ammonia storage tank is provided with two outlets which are respectively communicated with the flow controller and the reformer;
according to the fuel quantity required by an engine fuel injection strategy, the ECU adjusts the flow and pressure of liquid ammonia fuel entering the dual-fuel coaxial injection system through a liquid ammonia inlet and adjusts the flow and pressure of hydrogen-rich fuel entering the dual-fuel coaxial injection system through a hydrogen inlet; the energy ratio of the ammonia-hydrogen fuel of the reforming system is 1-40%, the pressure of the hydrogen-rich fuel entering the dual-fuel coaxial injection system is 5-30 MPa, the injection pressure of the liquid ammonia fuel under the condition of high-pressure injection is 5-100MPa, and the mass flow of the hydrogen-rich fuel is 0.1-0.2kg/s.
The dual-fuel coaxial injection system can coaxially inject liquid ammonia and hydrogen-rich fuel and comprises an installation sleeve, a shell, an oil nozzle, an input liquid ammonia channel and an input hydrogen pipeline, wherein the installation sleeve, the shell and the oil nozzle are sequentially arranged from top to bottom; the device comprises a mounting sleeve, a shell and a fuel spray nozzle, wherein a cavity formed in the mounting sleeve, the shell and the fuel spray nozzle is internally provided with a piston and a needle valve assembly, a liquid ammonia input channel and a hydrogen input pipeline are coaxially arranged in the shell, are not communicated and are respectively positioned at two sides of the cavity, and the liquid ammonia input channel and the hydrogen input pipeline are axially parallel to the central axis of the cavity;
the needle valve assembly is used for communicating/blocking the input liquid ammonia channel and the input hydrogen pipeline, the outer wall of the needle valve assembly is provided with two liquid inlets, and when the needle valve assembly moves upwards, the needle valve assembly is respectively communicated with the input liquid ammonia channel and the input hydrogen pipeline, so that liquid ammonia and hydrogen-rich fuel flow into corresponding injection holes; and the outer wall of the upper part of the needle valve component and the inner wall of the oil nozzle form cylindrical surface sealing, and a certain gap exists between the outer wall of the lower part of the needle valve component and the inner wall of the oil nozzle.
Further, the lower end of the oil nozzle is provided with the liquid ammonia oil spraying hole and the hydrogen spraying hole; the installation cavity, the piston cavity, the push rod cavity and the needle valve cavity are sequentially arranged in the cavity formed in the installation sleeve, the shell and the oil nozzle from top to bottom; the liquid ammonia input channel and the hydrogen input pipeline are axially parallel to the central axes of the mounting cavity and the piston cavity;
the installation cavity comprises a movable seat and a spring, a piston is arranged between the piston cavity and the installation cavity, the piston separates the piston cavity from the installation cavity, and the outer wall of the piston is in sealing connection with the inner wall of the piston cavity; a needle valve assembly is arranged in the needle valve cavity; a push rod is arranged in the push rod cavity;
the movable seat is characterized in that one end of the spring is fixedly connected to the top of the inner wall of the movable seat, the other end of the spring is fixedly connected to the top of the piston, the outer wall of the piston is in sealing connection with the inner wall of the piston cavity, and the piston is integrally connected with the push rod, so that when the piston moves up and down in the piston cavity, the piston drives the push rod to move up and down.
Further, the working end of the pretightening force adjusting component is fixedly connected to the top of the movable seat, and the ECU controls the movable seat to move downwards, so that the movable seat is pushed to move downwards, and pretightening force of the adjusting spring is realized.
Further, the movable seat is provided with an upper limit and a lower limit, the upper limit of the movable seat is that the top of the movable seat reaches the top wall of the inner wall of the mounting sleeve, and the lower limit of the movable seat is that the lower end of the movable seat reaches the flange at the upper end of the shell.
Further, a check valve is further arranged at the lower part of the oil nozzle and used for preventing liquid ammonia fuel from flowing back into the liquid ammonia input pipeline.
Further, the liquid ammonia oil injection hole is 5 spray holes, and the diameter of each spray hole is 1mm.
Further, the injection control method of the large-cylinder-diameter ship low-speed machine comprises the following steps:
when the fuel oil is started, the ECU controls the dual-fuel coaxial injection system and the reforming system to work, liquid ammonia fuel from the ammonia storage tank enters the fuel injector through the liquid ammonia branch, and simultaneously enters a flow of preparing hydrogen by reforming the liquid ammonia through the hydrogen reforming branch, and the prepared hydrogen-rich fuel enters the dual-fuel coaxial injection system to be prepared for injection;
then, the ECU controls the pretightening force adjusting assembly to move downwards to drive the movable seat, the spring, the piston, the push rod and the needle valve assembly to move downwards until the movable seat reaches the lower limit, and a liquid inlet on the needle valve assembly is communicated with the liquid inlet channel and the hydrogen inlet pipeline to enable liquid ammonia and ammonia-rich fuel to enter the tail ends of the liquid ammonia inlet channel and the hydrogen inlet pipeline through the liquid inlet on the outer wall of the needle valve assembly, and fuel is injected into the cylinder through the liquid ammonia injection hole and the hydrogen injection hole respectively;
and then according to the control of the ECU, the injection time of the liquid ammonia and the hydrogen-rich fuel into the cylinder is adjusted, so that the ammonia-hydrogen stratified injection is realized.
Further, the dual-fuel coaxial injection system is simulated to obtain a matched fuel injection molded line, a fuel injection sequence and a fuel injection interval time of the dual-fuel coaxial injection system, and obtain the ammonia-hydrogen fuel energy ratio of the reforming system, the flow of the flow regulator entering the liquid ammonia inlet of the liquid ammonia branch, the hydrogen-rich fuel temperature output by the intercooler, the pressure of the hydrogen-rich fuel output by the pressurizing pump and the hydrogen-rich fuel quantity flowing into the hydrogen inlet through the regulating valve.
Compared with the prior art, the technical scheme of the invention has the following beneficial effects:
the reforming system of the large-cylinder-diameter ship low-speed machine provided by the invention utilizes single ammonia fuel to provide liquid ammonia and hydrogen-rich fuel, so that the engine can realize dual-fuel continuous injection and dual-fuel coaxial injection; and the liquid ammonia channel and the hydrogen pipeline of the dual-fuel coaxial injection system are axially parallel to the central axes of the mounting cavity and the piston cavity, so that liquid ammonia and hydrogen-rich fuel can be coaxially injected in parallel.
Drawings
FIG. 1 is a schematic view of a marine low speed machine according to the present invention;
FIG. 2 is a cross-sectional view of a fuel injector according to the present invention;
FIG. 3 is a schematic diagram of the internal cavity of the dual fuel coaxial injection system of the present invention;
fig. 4 is a schematic cross-sectional view of the liquid ammonia injection hole according to the present invention.
In the figure:
1: fuel injector 2: liquid ammonia branch 3: flow controller
4: ammonia storage tank 5: reformer 6: intercooler
7: pressurizing pump 8: regulating valve 9: hydrogen reforming branch
10: liquid ammonia inlet 11: hydrogen inlet 101: liquid ammonia fuel injection hole
102: check valve 103: oil jet 104: liquid ammonia input pipeline
105: the input hydrogen line 106: pushrod 107: shell body
108: piston chamber 109: the piston 110: spring
111: the movable base 112: the mounting sleeve 113: pretightening force adjusting component
114: needle valve 115: needle valve body 116: hydrogen spraying hole
117: mounting cavity 118: pushrod cavity 119: needle valve cavity
Detailed Description
The technical solution of the present invention is described in further detail below with reference to the accompanying drawings and specific embodiments, which are only illustrative of the present invention and are not intended to limit the present invention.
As shown in fig. 1, the large-cylinder-diameter ship low-speed machine comprises a dual-fuel coaxial injection system and a reforming system, wherein the dual-fuel coaxial injection system is an oil sprayer 1 arranged on a cylinder cover of the ship low-speed machine, the reforming system is connected with the oil sprayer 1, and the reforming system comprises a liquid ammonia branch and a hydrogen reforming branch. The liquid ammonia branch circuit 2 comprises an ammonia storage tank 4, a flow controller 3 and a liquid ammonia inlet 10 of the oil sprayer which are sequentially connected through pipelines; the hydrogen reforming branch 9 comprises an ammonia storage tank 4, a reformer 5, an intercooler 6, a booster pump 7, a regulating valve 8 and a hydrogen inlet 11 of an oil injector which are sequentially connected through pipelines.
The fuel injector 1 is used for coaxially injecting liquid ammonia and hydrogen dual fuel, so that ammonia-hydrogen layered injection is realized; ammonia fuel from the liquid ammonia branch 2 enters the fuel injector 1 through a liquid ammonia inlet 10, and hydrogen-rich fuel from the hydrogen reforming branch 9 enters the fuel injector 1 through a hydrogen inlet 11.
The ammonia storage tank 4 is provided with two outlets, a first outlet and a second outlet, the first outlet is communicated with the flow controller 3, the flow controller 3 is controlled by the ECU, and the flow of liquid ammonia fuel entering the liquid ammonia inlet 10 is adjusted according to the fuel quantity required by an engine oil injection strategy. The second outlet of the ammonia storage tank 4 is communicated with the reformer 5, the reformer 5 is used for preparing hydrogen-rich fuel by reforming the introduced liquid ammonia through catalytic pyrolysis at a low temperature of a catalyst, the intercooler 6 is used for adjusting the temperature of the hydrogen-rich fuel to be consistent with the preset temperature of the fuel injector to be sprayed into the cylinder, the booster pump 7 is used for adjusting the pressure of the hydrogen-rich fuel to be consistent with the preset temperature of the fuel injector to be sprayed into the cylinder, and the adjusting valve 8 is used for adjusting the hydrogen-rich fuel quantity entering the hydrogen inlet 11 according to the hydrogen-rich fuel quantity required by an engine fuel injection strategy.
Specifically, as shown in fig. 2, the fuel injector 1 includes a mounting sleeve 112, a housing 107, a fuel nozzle 103, a liquid ammonia fuel injection hole 101, a hydrogen injection hole 116, an input liquid ammonia passage 104, and an input hydrogen gas pipe 105. The upper end of the shell 107 is connected with the mounting sleeve 112, the lower end of the shell 107 is provided with the oil nozzle 103, and the lower end of the oil nozzle 103 is provided with the liquid ammonia oil spray hole 101 and the hydrogen spray hole 116. The liquid ammonia oil spraying holes 101 are communicated with the tail end of the liquid ammonia input channel 104 and are used for spraying and conveying liquid ammonia fuel, and the hydrogen spraying holes 116 are communicated with the tail end of the hydrogen input pipeline 105 and are used for spraying and conveying hydrogen-rich fuel. One end of the input liquid ammonia channel 104 is connected with the liquid ammonia inlet 10, the other end is communicated with the oil nozzle 103, one end of the input hydrogen pipeline 105 is connected with the hydrogen inlet 11, and the other end is communicated with the oil nozzle 103.
As shown in fig. 3, a cavity is formed inside the mounting sleeve 112, the housing 107, and the fuel injection nozzle 103, and the cavity includes a mounting chamber 117, a piston chamber 108, a pushrod chamber 118, and a needle valve chamber 119, which are disposed in this order from top to bottom. The liquid ammonia input channel 104 and the hydrogen input channel 105 are coaxially arranged in the shell 107 and are respectively positioned at two sides of the cavity, the installation sleeve 112 is internally provided with an installation cavity 117, the installation cavity 117 comprises a movable seat 111 and a spring 110, a piston 109 is arranged between the piston cavity 108 and the installation cavity 117, the piston 109 separates the piston cavity 108 from the installation cavity 114, and the outer wall of the piston is in sealing connection with the inner wall of the piston cavity. The needle valve chamber 119 has a needle valve assembly (not shown) disposed therein, the needle valve assembly including a needle valve and a needle valve body.
And the pushrod 106 is disposed within the pushrod cavity 118. And the mounting cavity and the piston cavity are coaxially arranged.
The top of the fuel injector 1 (i.e. the top of the mounting sleeve 112) is provided with a pretightening force adjusting assembly 113, the pretightening force adjusting assembly 113 is controlled by the ECU, the top of the pretightening force adjusting assembly is connected with the cylinder cover, the top of the pretightening force adjusting assembly penetrates through the mounting sleeve and the bottom (i.e. the working end) of the pretightening force adjusting assembly is fixedly connected with the top of the movable seat 111, and the pretightening force adjusting assembly 113 can push the movable seat to move downwards when working so as to realize pretightening force of the adjusting spring. The outer wall and the top of the movable seat 111 are abutted against the inner wall of the mounting sleeve 112 and can axially move in the mounting cavity (slide along the inner wall of the mounting sleeve 112), the movable seat 111 is provided with a groove which is opened inwards from the lower end, the top of the inner wall of the movable seat is fixedly connected with one end of a spring 110, and the other end of the spring 110 is fixedly connected with the top of the piston 109. The piston 109 is located in the piston cavity 108, and the outer wall of the piston is in sealing connection with the inner wall of the piston cavity, and the piston 109 can slide along the piston cavity. The bottom of the piston 109 is provided with a push rod 106, and the upper end of the push rod 106 extends into the piston cavity and is integrally connected with the piston 109, so that when the piston moves up and down in the piston cavity, the piston 109 drives the push rod 106 to move up and down.
The bottom of the push rod 106 is connected with the top of the needle valve assembly, and two liquid inlets are formed in the outer wall of the needle valve body and are respectively used for communicating the tail ends of the liquid ammonia input channel 104 and the tail ends of the hydrogen input pipeline 105. The outer wall of the upper part of the needle valve body and the inner wall of the oil nozzle 103 form cylindrical surface sealing, and a certain gap exists between the outer wall of the lower part of the needle valve body and the inner wall of the oil nozzle.
The movable seat 111 has an upper limit and a lower limit, the upper limit of the movable seat 111 is that the top of the movable seat 111 reaches the top wall of the inner wall of the mounting sleeve 112, and the lower limit of the movable seat 111 is that the lower end of the movable seat 111 reaches the flange at the upper end of the housing 107.
As shown in fig. 2, a check valve 102 is further provided at the lower portion of the fuel injector 103, and the check valve 102 is provided to prevent backflow of liquid ammonia fuel into the input liquid ammonia pipe 104.
Under the regulation of the pretightening force regulating assembly 113, the moving seat 111 presses the spring 110, the spring outputs elastic force and acts the elastic force on the piston 109, the elastic force output by the spring is pretightening force, the pretightening force pushes the piston 109 to move downwards, the piston has downward moving force, so that the push rod 106 is driven to move downwards, at the moment, 2 liquid inlets on the outer wall of the needle valve body are respectively communicated with the tail ends of the liquid ammonia inputting channel 104 and the hydrogen inputting channel 105, and liquid ammonia and ammonia-rich fuel enter the tail ends of the liquid ammonia inputting channel 104 and the hydrogen inputting channel 105 through the liquid inlets until the moving seat 111 reaches the lower limit, namely, the lower end is seated on the flange at the upper end of the shell 107, and are respectively sprayed into the cylinder through the liquid ammonia spraying hole 101 and the hydrogen spraying hole 116. Then, under the reaction force of the spring, the push rod 106 is driven to move upwards, at this time, the 2 liquid inlets on the outer wall of the needle valve body are not communicated with the ends of the liquid ammonia input channel 104 and the hydrogen input pipeline 105 until the upper end of the moving seat 111 reaches the top wall of the inner wall of the mounting sleeve 112 to stop moving upwards, and then the needle valve body continues to move downwards until the injection preset by the ECU is completed.
The fuel injector can realize dual-fuel continuous injection and dual-fuel coaxial injection required in a layered fuel injection strategy of an engine. The specific injection control method is as follows:
the method comprises the steps of performing simulation calculation on the injection of an injector by using commercial simulation software (such as conversion software), wherein the single-cylinder power of an original engine is 2500KW, the heat value of liquid ammonia is 18.6KJ/g, the low-level heat value of hydrogen is 120KJ/g, the matching injection molded line, the injection sequence and the injection interval time of the injector 1 are obtained through calculation, the energy ratio of ammonia and hydrogen fuel of a reforming system is 10%, the flow of a flow regulator 3 entering a liquid ammonia inlet 10 of a liquid ammonia branch 2 is 120.9677g, the temperature of hydrogen-rich fuel output by an intercooler 6 is 300K-350K, the pressure of hydrogen-rich fuel output by a pressurizing pump 7 is 5MPa-30MPa, and the hydrogen-rich fuel quantity flowing into a hydrogen inlet 11 is regulated to be 2.083g by a regulating valve 8; and transmitting the calculated parameters to the fuel injector and the reforming system through the ECU;
when the fuel oil is started, the ECU controls the fuel injector 1 and the reforming system to start working, liquid ammonia fuel from the ammonia storage tank 4 enters the fuel injector 1 through the liquid ammonia branch 2, and simultaneously enters a flow of preparing hydrogen by reforming the liquid ammonia through the hydrogen reforming branch 9, and the prepared hydrogen-rich fuel enters the fuel injector 1 to be prepared for injection;
subsequently, the ECU controls the pretightening force adjusting assembly 113 to move downwards to drive the moving seat 111, the spring 110, the piston 109, the push rod 106 and the needle valve assembly to move downwards, so that liquid ammonia and ammonia-rich fuel enter the ends of the liquid ammonia input channel 104 and the hydrogen input pipeline 105 through liquid inlets positioned on the outer wall of the needle valve assembly until the moving seat 111 reaches the lower limit (the lower end is seated on the flange at the upper end of the shell 107), and oil is injected into the cylinder through the liquid ammonia oil injection hole 101 and the hydrogen injection hole 116 respectively;
and then according to the control of the ECU, the injection time of the liquid ammonia and the hydrogen-rich fuel into the cylinder is adjusted, so that the ammonia-hydrogen stratified injection is realized.
As shown in fig. 4, the liquid ammonia injection hole 101 has 5 injection holes, each of which has a diameter of about 1mm. The plurality of spray holes are arranged, and the aperture is slightly larger than that of a spray hole of a normal oil sprayer, so that the flow and the pressure are regulated by the method disclosed by the invention, and the relation of the oil spraying quality, the flow and the pressure can be further satisfied. And when the large-aperture spray holes are adopted for spraying oil, the flow area can be increased near the top dead center of the engine to promote combustion.
Although the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to the above-described embodiments, which are merely illustrative and not restrictive, and many forms may be made by those having ordinary skill in the art without departing from the spirit of the present invention and the scope of the appended claims, which are within the scope of the present invention.

Claims (8)

1. The large-cylinder-diameter ship low-speed machine is characterized by comprising a dual-fuel coaxial injection system and a reforming system, wherein the dual-fuel coaxial injection system is arranged on a cylinder cover; the reforming system comprises a liquid ammonia branch circuit (2) and a hydrogen reforming branch circuit (9); the liquid ammonia branch circuit (2) comprises an ammonia storage tank (4), a flow controller (3) and a liquid ammonia inlet (10) of the dual-fuel coaxial injection system which are sequentially connected through pipelines; the hydrogen reforming branch circuit (9) comprises an ammonia storage tank (4), a reformer (5), an intercooler (6), a pressure pump (7), a regulating valve (8) and a hydrogen inlet (11) of the dual-fuel coaxial injection system which are sequentially connected through pipelines;
the ammonia storage tank (4) is provided with two outlets which are respectively communicated with the flow controller (3) and the reformer (5);
the dual-fuel coaxial injection system comprises a mounting sleeve (112), a shell (107) and an oil nozzle (103) which are sequentially arranged from top to bottom, and further comprises an input liquid ammonia channel (104) and an input hydrogen pipeline (105) which are coaxially arranged in the shell (107), wherein the top end of the input liquid ammonia channel (104) is communicated with a liquid ammonia inlet (10), the tail end of the input liquid ammonia channel is communicated with a liquid ammonia oil injection hole (101) and is used for injecting liquid ammonia fuel, the top end of the input hydrogen pipeline 105 is communicated with a hydrogen inlet (11), and the tail end of the input hydrogen pipeline is communicated with a hydrogen injection hole (116) and is used for injecting hydrogen-rich fuel; the installation sleeve (112), the shell (107) and the oil nozzle (103) are internally provided with a piston and needle valve assembly, the input liquid ammonia channel (104) and the input hydrogen pipeline (105) are coaxially arranged in the shell (107), are not communicated and are respectively positioned at two sides of the cavity, and the input liquid ammonia channel (104) and the input hydrogen pipeline (105) are axially parallel to the central axis of the cavity;
the needle valve assembly is used for communicating/blocking the liquid ammonia input channel (104) and the hydrogen input pipeline (105), two liquid inlets are formed in the outer wall of the needle valve assembly, and when the needle valve assembly moves upwards, the liquid ammonia input channel (104) and the hydrogen input pipeline (105) are respectively communicated, so that liquid ammonia and hydrogen-enriched fuel flow into corresponding injection holes; the outer wall of the upper part of the needle valve assembly and the inner wall of the oil nozzle (103) form cylindrical surface sealing, and a certain gap exists between the outer wall of the lower part of the needle valve assembly and the inner wall of the oil nozzle;
according to the fuel quantity required by an engine oil injection strategy, the ECU adjusts the flow and pressure of liquid ammonia fuel entering the dual-fuel coaxial injection system through a liquid ammonia inlet (10) and adjusts the flow and pressure of hydrogen-rich fuel entering the dual-fuel coaxial injection system through a hydrogen inlet (11); wherein the energy ratio of the ammonia and hydrogen fuel of the reforming system is 1-40% of hydrogen, the pressure of the hydrogen-rich fuel entering the dual-fuel coaxial injection system is 5-30 MPa, the injection pressure of liquid ammonia is 5-100MPa, and the mass flow of the hydrogen-rich fuel is 0.1-0.2kg/s.
2. The large-cylinder-diameter ship low-speed machine according to claim 1, wherein the lower end of the oil nozzle (103) is provided with the liquid ammonia oil injection hole (101) and the hydrogen injection hole (116); in the cavity formed in the mounting sleeve (112), the shell (107) and the oil nozzle (103), a mounting cavity (117), a piston cavity (108), a push rod cavity (118) and a needle valve cavity (119) are sequentially arranged from top to bottom; the liquid ammonia input channel and the hydrogen input pipeline are axially parallel to the central axes of the mounting cavity and the piston cavity;
the mounting cavity (117) comprises a moving seat (111) and a spring (110), a piston (109) is arranged between the piston cavity (108) and the mounting cavity (117), the piston (109) separates the piston cavity (108) from the mounting cavity (117), and the outer wall of the piston is in sealing connection with the inner wall of the piston cavity; a needle valve assembly is arranged in the needle valve cavity (119); and a push rod (106) is arranged in the push rod cavity (118);
one end of a spring (110) is fixedly connected to the top of the inner wall of the movable seat (111), the other end of the spring (110) is fixedly connected to the top of a piston (109), the outer wall of the piston is in sealing connection with the inner wall of a piston cavity, and the piston (109) is integrally connected with a push rod (106), so that when the piston moves up and down in the piston cavity, the piston (109) drives the push rod (106) to move up and down.
3. The large-bore marine low speed machine according to claim 2, wherein a working end of a preload adjustment assembly (113) is fixedly connected to the top of the movable seat (111), and is controlled by the ECU to move downward, thereby pushing the movable seat to move downward, and realizing the preload of the adjustment spring.
4. The large-bore marine low speed machine according to claim 2, wherein the movable seat (111) has an upper limit and a lower limit, the upper limit of the movable seat (111) is that the top of the movable seat (111) reaches the top wall of the inner wall of the mounting sleeve (112), and the lower limit of the movable seat (111) is that the lower end of the movable seat (111) reaches the flange at the upper end of the housing (107).
5. A large bore marine low speed machine according to claim 2, characterized in that a check valve (102) is also provided in the lower part of the nozzle (103) for preventing backflow of liquid ammonia fuel into the incoming liquid ammonia conduit (104).
6. The large-bore marine low speed machine according to claim 2, wherein the liquid ammonia injection holes (101) are 5 injection holes, each injection hole having a diameter of 1mm.
7. The injection control method of the large-bore marine low speed machine according to claim 2, comprising:
when the fuel oil is started, the ECU controls the dual-fuel coaxial injection system and the reforming system to work, liquid ammonia fuel from the ammonia storage tank (4) enters the dual-fuel coaxial injection system through the liquid ammonia branch (2), and simultaneously enters a flow of preparing hydrogen by reforming the liquid ammonia through the hydrogen reforming branch (9), and the prepared hydrogen-rich fuel enters the dual-fuel coaxial injection system for injection preparation;
subsequently, the ECU controls the pretightening force adjusting assembly (113) to move downwards to drive the movable seat (111), the spring (110), the piston (109), the push rod (106) and the needle valve assembly to move downwards until the movable seat (111) reaches the lower limit, and a liquid inlet on the needle valve assembly is communicated with the input liquid ammonia channel (104) and the input hydrogen pipeline (105), so that liquid ammonia and ammonia-rich fuel enter the tail ends of the input liquid ammonia channel (104) and the input hydrogen pipeline (105) through the liquid inlet on the outer wall of the needle valve assembly, and fuel is injected into a cylinder through the liquid ammonia injection hole (101) and the hydrogen injection hole (116) respectively;
and then according to the control of the ECU, the injection time of the liquid ammonia and the hydrogen-rich fuel into the cylinder is adjusted, so that the ammonia-hydrogen stratified injection is realized.
8. The injection control method of the large-cylinder-diameter ship low-speed machine according to claim 7, characterized in that the matched fuel injection line, the fuel injection sequence and the fuel injection interval time of the dual-fuel coaxial injection system are obtained through simulation of the dual-fuel coaxial injection system, the ammonia-hydrogen fuel energy ratio of the reforming system, the flow of the flow regulator (3) entering the liquid ammonia inlet (10) of the liquid ammonia branch (2), the hydrogen-rich fuel temperature output by the intercooler (6), the pressure of the hydrogen-rich fuel output by the pressurizing pump (7) and the hydrogen-rich fuel quantity flowing into the hydrogen inlet (11) are obtained through the regulating valve (8).
CN202311687950.1A 2023-12-08 2023-12-08 Large-cylinder-diameter ship low-speed machine and injection control method thereof Pending CN117514531A (en)

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CN202311687950.1A CN117514531A (en) 2023-12-08 2023-12-08 Large-cylinder-diameter ship low-speed machine and injection control method thereof

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CN202311687950.1A CN117514531A (en) 2023-12-08 2023-12-08 Large-cylinder-diameter ship low-speed machine and injection control method thereof

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CN117514531A true CN117514531A (en) 2024-02-06

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