CN112761780A - Lean combustion system and method and engine - Google Patents
Lean combustion system and method and engine Download PDFInfo
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- CN112761780A CN112761780A CN201911001103.9A CN201911001103A CN112761780A CN 112761780 A CN112761780 A CN 112761780A CN 201911001103 A CN201911001103 A CN 201911001103A CN 112761780 A CN112761780 A CN 112761780A
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B43/00—Engines characterised by operating on gaseous fuels; Plants including such engines
- F02B43/10—Engines or plants characterised by use of other specific gases, e.g. acetylene, oxyhydrogen
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
- F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
- F01L1/26—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of two or more valves operated simultaneously by same transmitting-gear; peculiar to machines or engines with more than two lift-valves per cylinder
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D13/00—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing
- F02D13/02—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing during engine operation
- F02D13/0203—Variable control of intake and exhaust valves
- F02D13/0215—Variable control of intake and exhaust valves changing the valve timing only
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- 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
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- 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
- F02D41/401—Controlling injection timing
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- 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
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
- F02F1/00—Cylinders; Cylinder heads
- F02F1/24—Cylinder heads
- F02F1/242—Arrangement of spark plugs or injectors
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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
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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
- F02M21/0218—Details on the gaseous fuel supply system, e.g. tanks, valves, pipes, pumps, rails, injectors or mixers
- F02M21/0245—High pressure fuel supply systems; Rails; Pumps; Arrangement of valves
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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
- F02M21/0218—Details on the gaseous fuel supply system, e.g. tanks, valves, pipes, pumps, rails, injectors or mixers
- F02M21/0248—Injectors
- F02M21/0275—Injectors for in-cylinder direct injection, e.g. injector combined with spark plug
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02P—IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES
- F02P5/00—Advancing or retarding ignition; Control therefor
- F02P5/04—Advancing or retarding ignition; Control therefor automatically, as a function of the working conditions of the engine or vehicle or of the atmospheric conditions
- F02P5/145—Advancing or retarding ignition; Control therefor automatically, as a function of the working conditions of the engine or vehicle or of the atmospheric conditions using electrical means
- F02P5/15—Digital data processing
- F02P5/1502—Digital data processing using one central computing unit
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- 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
Abstract
The invention provides a lean-burn system, a method and an engine, wherein the lean-burn system comprises a high-pressure injection unit, an ignition unit, an air inlet unit, an exhaust unit, a combustion chamber and a piston; the piston is capable of reciprocating within the combustion chamber; the high-pressure injection unit, the ignition unit, the air inlet unit and the exhaust unit are all arranged at the top of the combustion chamber; the high-pressure injection unit comprises a high-pressure hydrogen injector which is an umbrella-shaped spray oil injector and is used for directly injecting umbrella-shaped hydrogen spray to the combustion chamber; the air inlet unit comprises an air inlet valve and an air inlet channel which are connected; the exhaust unit comprises an exhaust valve and an exhaust passage which are connected; the ignition unit is used for burning fuel in the combustion chamber. The lean-burn engine comprises at least one lean-burn system as described above, and the lean-burn method is applied to the engine as described above. The invention can realize low emission and even zero emission of NOx and improve the heat efficiency.
Description
Technical Field
The invention relates to the technical field of engines, in particular to a lean combustion system, a lean combustion method and an engine.
Background
The development of alternative fuels for application in conventional internal combustion engines is one of the important directions for achieving emission reduction, energy conservation and promoting energy safety. Hydrogen gas is an ideal fuel for internal combustion engines because of its carbon-free, wide ignition range, high octane number and calorific value. Wherein, the carbon-free characteristic realizes zero emission of CO, HC and particulate matters (PN/PM). The wide ignition range, high octane number and heat value are beneficial to realizing ultra-lean combustion and high geometric compression ratio, thereby achieving the purpose of high efficiency.
At present, spark ignition type hydrogen internal combustion engines mainly comprise two modes of hydrogen gas inlet channel injection and in-cylinder direct injection. Compared with the hydrogen gas inlet channel injection, the advantages of direct injection in the cylinder are obvious, abnormal combustion such as backfire and pre-ignition is avoided, the power per liter is high, and the like. However, the major technical bottlenecks faced by direct injection in hydrogen cylinders include:
1) high load NOx emissions are high. The key approach to reducing NOx in hydrogen internal combustion engines is to form a homogeneous lean mixture in each part of the combustion chamber. The existing hydrogen nozzle mainly adopts a porous oil injector, so that the uniform mixing of hydrogen and air is not facilitated, and the original NOx emission is high under high load.
2) The thermal efficiency is low. Since the quenching distance of hydrogen is short (about 1/4 for natural gas and gasoline), the heat transfer loss of the hydrogen internal combustion engine is large, thereby limiting the improvement of the thermal efficiency.
Disclosure of Invention
The invention aims to provide a lean-burn system, a lean-burn method and an engine, which can improve the thermal efficiency of the engine while realizing near-zero emission of NOx.
The invention provides a lean combustion system, which comprises a high-pressure injection unit, an ignition unit, an air inlet unit, an exhaust unit, a combustion chamber and a piston, wherein the high-pressure injection unit is connected with the ignition unit;
the piston is reciprocable within the combustion chamber;
the high-pressure injection unit, the ignition unit, the air inlet unit and the exhaust unit are all arranged at the top of the combustion chamber;
the high-pressure injection unit comprises a high-pressure hydrogen injector, the high-pressure hydrogen injector is an umbrella-shaped spray oil injector, and the high-pressure hydrogen injector is used for directly injecting umbrella-shaped hydrogen spray to the combustion chamber;
the air inlet unit comprises an air inlet valve and an air inlet channel which are connected, and the combustion chamber is communicated with the outside atmosphere through the air inlet unit;
the exhaust unit comprises an exhaust valve and an exhaust passage which are connected, and the combustion chamber is communicated with the outside atmosphere through the exhaust unit;
the ignition unit is used for burning fuel in the combustion chamber.
Optionally, the intake unit further includes an intake valve lift mechanism, the intake valve lift mechanism is configured to continuously change an opening time of the intake valve, and the exhaust unit further includes an exhaust valve lift mechanism, and the exhaust valve lift mechanism is configured to continuously change an opening time of the exhaust valve.
Optionally, the ignition unit comprises an ignition coil and a spark plug connected.
Alternatively, the umbrella-shaped hydrogen gas spray injected by the high-pressure hydrogen gas injector is directed to a position close to the ignition plug.
Optionally, the high-pressure hydrogen injector and the ignition unit are both located between the air intake unit and the exhaust unit, and the ignition unit is close to the exhaust unit.
Optionally, the high-pressure injection unit further includes a high-pressure hydrogen storage device, a pressure control valve and a high-pressure hydrogen rail that are connected in sequence, and an air outlet of the high-pressure hydrogen rail is connected with an air inlet of the high-pressure hydrogen injector.
Optionally, the injection pressure of the high-pressure hydrogen injector is not lower than 30 bar.
Optionally, the high-pressure hydrogen injector is an external open ring injector or a vortex type injector.
Optionally, the piston is a high compression ratio piston.
Optionally, the air inlet unit is located at one side of the top of the combustion chamber, the air outlet unit is located at the other side of the top of the combustion chamber, and the high-pressure hydrogen injector is close to the middle position of the top of the combustion chamber.
To achieve the above object, the present invention also provides a lean-burn engine including at least one of the above-described lean-burn systems.
To achieve the above object, the present invention also provides a lean combustion method including:
under the low-load working condition, aiming at one working cycle, after a period of time from the beginning of an intake stroke, directly injecting umbrella-shaped hydrogen spray to the combustion chamber through the high-pressure hydrogen injector;
under the medium-load working condition, aiming at one working cycle, at the end of an intake stroke, directly injecting umbrella-shaped hydrogen spray to the combustion chamber through the high-pressure hydrogen injector;
and under a high-load working condition, after an intake valve is closed, injecting umbrella-shaped hydrogen spray into the combustion chamber at least twice through the high-pressure hydrogen injector and igniting once through the ignition unit, wherein the first injection of the umbrella-shaped hydrogen spray occurs before ignition and the last injection of the umbrella-shaped hydrogen spray occurs after ignition.
Optionally, under a high-load condition, after the intake valve is closed, the high-pressure hydrogen injector injects umbrella-shaped hydrogen spray into the combustion chamber at least twice, and the ignition unit ignites twice, wherein the first injection of umbrella-shaped hydrogen spray occurs before the first ignition is started, and the last injection of umbrella-shaped hydrogen spray occurs in the time period from the first ignition to the second ignition or during the second ignition.
Optionally, under a high-load working condition, the time interval from the ignition starting moment to the injection starting moment of the last umbrella-shaped hydrogen spray is 0-20 degrees of crank angle.
Optionally, under a high-load working condition, a time interval from the first ignition start time to the last umbrella-shaped hydrogen spray injection start time is 0 to 20 crank angle degrees, and a time interval from the last umbrella-shaped hydrogen spray injection start time to the second ignition start time is 0 to 20 crank angle degrees.
Compared with the prior art, the lean combustion system, the method and the engine provided by the invention have the following advantages:
(1) the invention provides a lean combustion system which comprises a high-pressure injection unit, an ignition unit, an air inlet unit, an exhaust unit, a combustion chamber and a piston, wherein the high-pressure injection unit is connected with the ignition unit; the piston is reciprocable within the combustion chamber; the high-pressure injection unit, the ignition unit, the air inlet unit and the exhaust unit are all arranged at the top of the combustion chamber; the high-pressure injection unit comprises a high-pressure hydrogen injector, the high-pressure hydrogen injector is an umbrella-shaped spray oil injector, and the high-pressure hydrogen injector is used for directly injecting umbrella-shaped hydrogen spray to the combustion chamber; the air inlet unit comprises an air inlet valve and an air inlet channel which are connected, and the combustion chamber is communicated with the outside atmosphere through the air inlet unit; the exhaust unit comprises an exhaust valve and an exhaust passage which are connected, and the combustion chamber is communicated with the outside atmosphere through the exhaust unit; the ignition unit is used for burning fuel in the combustion chamber. Therefore, fresh air can be input into the combustion chamber through the air inlet unit, high-pressure umbrella-shaped hydrogen spray can be input into the combustion chamber through the high-pressure hydrogen injector, and therefore a uniform lean mixture with the equivalent air-fuel ratio larger than 2 can be formed in the combustion chamber. Compared with a conventional porous (more than or equal to 2 holes) injector of an internal combustion engine directly injecting hydrogen in a cylinder, the lean combustion system provided by the invention can enlarge the contact area of hydrogen and air and promote the rapid and uniform mixing of hydrogen and air by adopting the umbrella-shaped spray oil injector as a high-pressure hydrogen injector, thereby realizing the low emission and even zero emission of NOx.
(2) The lean-burn engine provided by the invention has all the advantages of the lean-burn system because the lean-burn engine comprises at least one lean-burn system, namely, the lean-burn engine provided by the invention adopts the umbrella-shaped spray injector as the high-pressure hydrogen injector, and compared with a conventional porous (more than or equal to 2 holes) injector of an internal combustion engine which directly injects hydrogen in a cylinder, the lean-burn engine can enlarge the contact area of hydrogen and air, promote the rapid and uniform mixing of the hydrogen and the air, and further realize the low emission and even zero emission of NOx.
(3) The invention provides a lean combustion method, which comprises the following steps: under the low-load working condition, aiming at one working cycle, after a period of time from the beginning of an intake stroke, directly injecting umbrella-shaped hydrogen spray to the combustion chamber through the high-pressure hydrogen injector; under the medium-load working condition, aiming at one working cycle, at the end of an intake stroke, directly injecting umbrella-shaped hydrogen spray to the combustion chamber through the high-pressure hydrogen injector; under the high-load working condition, after an air inlet valve is closed, the high-pressure hydrogen injector injects umbrella-shaped hydrogen to the combustion chamber at least twice, and the ignition unit ignites once, wherein the first injection of the hydrogen spray occurs before ignition, the last injection of the hydrogen spray occurs after ignition, or under high load conditions, for one duty cycle, after the air inlet valve is closed, the high-pressure hydrogen injector injects umbrella-shaped hydrogen spray into the combustion chamber at least twice, and the ignition unit ignites twice, wherein the first injection of the hydrogen spray occurs before the first ignition begins and the last injection of the hydrogen spray occurs during a period of time after the first ignition and before the second ignition or during the second ignition. Therefore, the hydrogen injection strategy adopted by the lean combustion method under medium and low loads can realize the stable combustion of the uniform lean mixture with equivalent air-fuel ratio more than 2, thereby achieving the purpose of low or even zero NOx emission; the hydrogen multi-injection strategy adopted under high load can realize multi-stage heat release combustion, and reduce the emission of NOx while improving the heat efficiency.
Drawings
FIG. 1 is a schematic diagram of an overall lean burn system according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of an umbrella-shaped hydrogen spray jet in accordance with one embodiment of the present invention;
FIG. 3 is a schematic representation of engine operating conditions according to an embodiment of the present invention;
FIG. 4 is a schematic diagram of the control strategy of air intake, high pressure hydrogen injection and ignition under low load conditions in accordance with an embodiment of the present invention;
FIG. 5 is a schematic diagram of an intake, high pressure hydrogen injection and ignition control strategy under medium load conditions in accordance with an embodiment of the present invention;
FIG. 6 is a schematic diagram of the intake, high pressure hydrogen injection and ignition control strategy under high load conditions in accordance with an embodiment of the present invention;
FIG. 7 is a schematic diagram of the intake, high pressure hydrogen injection and ignition control strategy under high load conditions in accordance with another embodiment of the present invention;
FIG. 8 is a schematic comparison of a multi-stage heat release strategy of the present invention with a conventional single stage heat release strategy.
Wherein the reference numbers are as follows:
a high pressure injection unit-100; an ignition unit-200; an air intake unit-300; an exhaust unit-400; a combustion chamber-500; a piston-600; a high pressure hydrogen injector-110; an intake valve-310; an inlet channel-320; an exhaust valve-410; an exhaust passage-420; an ignition coil-210; a spark plug-220; high pressure hydrogen storage-120; -130, a pressure control valve; high pressure hydrogen rail-140.
Detailed Description
The lean-burn system, method and engine of the present invention will be described in further detail with reference to the accompanying fig. 1-8 and the detailed description. The advantages and features of the present invention will become more apparent from the following description. It is to be noted that the drawings are in a very simplified form and are all used in a non-precise scale for the purpose of facilitating and distinctly aiding in the description of the embodiments of the present invention. To make the objects, features and advantages of the present invention comprehensible, reference is made to the accompanying drawings. It should be understood that the structures, ratios, sizes, and the like shown in the drawings and described in the specification are only used for matching with the disclosure of the specification, so as to be understood and read by those skilled in the art, and are not used to limit the implementation conditions of the present invention, so that the present invention has no technical significance, and any structural modification, ratio relationship change or size adjustment should still fall within the scope of the present invention without affecting the efficacy and the achievable purpose of the present invention.
It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
In the description of the present invention, it is to be understood that the terms "center," "height," "thickness," "upper," "lower," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the present invention and for simplicity in description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and are not to be considered limiting. In the description of the present invention, "a plurality" means two or more unless otherwise specified.
In the description of the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "fixed" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral part; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.
As described in the background, the spark ignition type hydrogen internal combustion engine mainly includes two modes of hydrogen gas inlet injection and direct in-cylinder injection. Compared with the hydrogen gas inlet channel injection, the advantages of direct injection in the cylinder are obvious, abnormal combustion such as backfire and pre-ignition is avoided, the power per liter is high, and the like. However, the major technical bottlenecks faced by direct injection in hydrogen cylinders include:
1) high load NOx emissions are high. The key approach to reducing NOx in hydrogen internal combustion engines is to form a homogeneous lean mixture in each part of the combustion chamber. The existing hydrogen nozzle mainly adopts a porous oil injector, so that the uniform mixing of hydrogen and air is not facilitated, and the original NOx emission is high under high load.
2) The thermal efficiency is low. Since the quenching distance of hydrogen is short (about 1/4 for natural gas and gasoline), the heat transfer loss of the hydrogen internal combustion engine is large, thereby limiting the improvement of the thermal efficiency.
The core idea of the invention is to provide a lean-burn system, a lean-burn method and an engine, which can improve the thermal efficiency of the engine while realizing near-zero emission of NOx.
To achieve the above idea, the present invention provides a lean combustion system, and refer to fig. 1, which schematically shows an overall structure of a lean combustion system according to an embodiment of the present invention. As shown in fig. 1, the lean burn system includes a high-pressure injection unit 100, an ignition unit 200, an intake unit 300, an exhaust unit 400, a combustion chamber 500, and a piston 600.
Wherein the piston 600 is capable of reciprocating within the combustion chamber 500. Preferably, the piston 600 is a high compression ratio piston 600. Therefore, the piston 600 adopts the high-compression-ratio piston 600, the geometric compression ratio of the combustion chamber 500 can reach more than 12:1, and lean combustion can be better realized.
The high-pressure injection unit 100, the ignition unit 200, the intake unit 300, and the exhaust unit 400 are all disposed at the top of the combustion chamber 500. The high-pressure injection unit 100 is used for directly injecting hydrogen into the combustion chamber 500, the intake unit 300 is used for introducing fresh air into the combustion chamber 500, the exhaust unit 400 is used for discharging exhaust gas generated in the combustion process, and the ignition unit 200 is used for combusting fuel in the combustion chamber 500.
The intake unit 300 includes an intake valve 310 and an intake passage 320 connected to each other, and the combustion chamber 500 communicates with the outside atmosphere through the intake unit 300. When the intake valve 310 is closed, the intake passage 320 is blocked; when the intake valve 310 is opened, the intake passage 320 is communicated with the outside atmosphere, so that fresh air can be introduced into the combustion chamber 500 through the intake passage 320.
Preferably, the intake unit 300 further includes an intake valve lift mechanism (not shown) for continuously changing an opening timing of the intake valve 310. Thus, by providing an intake valve lift mechanism in the intake unit 300, it is possible to more easily control the opening and closing of the intake valve 310.
The high-pressure injection unit 100 includes a high-pressure hydrogen injector 110, the high-pressure hydrogen injector 110 is an umbrella-shaped spray injector, and the high-pressure hydrogen injector 110 is configured to directly inject umbrella-shaped hydrogen spray to the combustion chamber 500. In the lean combustion system provided by the invention, the high-pressure hydrogen injector 110 is an umbrella-shaped spray injector, and compared with a porous (more than or equal to 2 holes) injector of a conventional direct injection hydrogen internal combustion engine, the high-pressure hydrogen injector can enlarge the contact area of hydrogen and air and promote the uniform and rapid mixing of the hydrogen and the air, thereby laying a foundation for realizing low NOx and even zero NOx emission.
Preferably, the high pressure injection unit 100 further includes a high pressure hydrogen storage device 120, a pressure control valve 130 and a high pressure hydrogen rail 140, which are connected in sequence, and an air outlet of the high pressure hydrogen rail 140 is connected to an air inlet of the high pressure hydrogen injector 110. The air inlet of the high-pressure hydrogen rail 140 is connected to the air outlet of the high-pressure hydrogen storage device 120 through a pipeline, the air outlet of the high-pressure hydrogen rail 140 is connected to the air inlet of the high-pressure hydrogen injector 110 through a pipeline, and the pressure control valve 130 is disposed on the connecting pipeline between the high-pressure hydrogen storage device 120 and the high-pressure hydrogen rail 140. The high-pressure light rail may be used to store hydrogen gas while suppressing pressure fluctuation generated by the high-pressure hydrogen injector 110 during injection of the gas, thereby ensuring pressure stability of the high-pressure injection unit 100.
Preferably, the high-pressure hydrogen injector 110 is an open-ring injector or a swirl-type injector.
Preferably, the injection pressure of the high-pressure hydrogen injector 110 is not lower than 30 bar. Since the injection pressure of the high-pressure hydrogen injector 110 is not lower than 30bar, more uniform umbrella-shaped hydrogen spray can be generated, and lean combustion can be better realized. In addition, since the injection pressure of the high-pressure hydrogen injector 110 is large, the high-speed spray increases the intensity of turbulence around the ignition unit 200, thereby increasing the propagation speed of the initial flame, so that the lean mixture is stably combusted.
The exhaust unit 400 includes an exhaust valve 410 and an exhaust passage 420 connected, and the combustion chamber 500 communicates with the outside atmosphere through the exhaust unit 400. When the exhaust valve 410 is closed, the exhaust passage 420 is blocked; when the exhaust valve 410 is opened, the exhaust passage 420 is communicated with the outside atmosphere, so that exhaust gas generated by combustion in the combustion chamber 500 can be discharged through the exhaust passage 420.
Preferably, the exhaust unit 400 further includes an exhaust valve lift mechanism (not shown) for continuously changing an opening timing of the exhaust valve 410. Thus, by providing the exhaust valve lift mechanism in the exhaust unit 400, it is possible to more easily control the opening and closing of the exhaust valve 410.
Preferably, the ignition unit 200 includes an ignition coil 210 and a spark plug 220 connected thereto. As a result, the ignition coil 210 can discharge the spark plug 220, and the fuel in the combustion chamber 500 can be combusted by the discharge.
Preferably, the umbrella-shaped hydrogen gas spray injected from the high-pressure hydrogen injector 110 is directed to a position close to the ignition plug 220. Since the umbrella-shaped hydrogen gas spray injected from the high-pressure hydrogen injector 110 is directed to a position close to the ignition plug 220, combustion stability and robustness of lean combustion can be ensured.
Preferably, the high pressure hydrogen injector 110 and the ignition unit 200 are both located between the intake unit 300 and the exhaust unit 400, and the ignition unit 200 is located close to the exhaust unit 400. Since the temperature of the exhaust unit 400 is too high, the high-pressure hydrogen injector 110 can be far away from the exhaust unit 400 by disposing the high-pressure injector and the ignition unit 200 between the intake unit 300 and the exhaust unit 400, and the ignition unit 200 is close to the exhaust unit 400, so as to prevent the high-pressure hydrogen injector 110 from being damaged due to high temperature.
Preferably, the intake unit 300 is located at one side of the top of the combustion chamber 500, the exhaust unit 400 is located at the other side of the top of the combustion chamber 500, and the high pressure hydrogen injector 110 is located near the middle of the top of the combustion chamber 500. Thus, this arrangement can facilitate the arrangement of the intake unit 300, the exhaust unit 400, and the high-pressure injection unit 100, and can enable the hydrogen and air in the combustion chamber 500 to be uniformly mixed more rapidly and to better achieve lean combustion by providing the high-pressure hydrogen injector 110 at an intermediate position near the top of the combustion chamber 500. It should be noted that the high-pressure hydrogen injector 110 may also be disposed on the side of the top of the combustion chamber 500, and near the position of the air intake unit 300, which is not limited in the present invention.
In summary, the lean combustion system provided by the present invention includes a high-pressure injection unit 100, an ignition unit 200, an intake unit 300, an exhaust unit 400, a combustion chamber 500, and a piston 600; the piston 600 is capable of reciprocating within the combustion chamber 500; the high-pressure injection unit 100, the ignition unit 200, the intake unit 300, and the exhaust unit 400 are all disposed at the top of the combustion chamber 500; the high-pressure injection unit 100 includes a high-pressure hydrogen injector 110, the high-pressure hydrogen injector 110 is an umbrella-shaped spray injector, and the high-pressure hydrogen injector 110 is configured to directly inject umbrella-shaped hydrogen spray to the combustion chamber 500; the intake unit 300 comprises an intake valve 310 and an intake passage 320 which are connected, and the combustion chamber 500 is communicated with the external atmosphere through the intake unit 300; the exhaust unit 400 comprises an exhaust valve 410 and an exhaust passage 420 which are connected, and the combustion chamber 500 is communicated with the external atmosphere through the exhaust unit 400; the ignition unit 200 is used to combust fuel in the combustion chamber 500. Accordingly, fresh air can be supplied into the combustion chamber 500 through the air intake means 300, and a high-pressure hydrogen gas spray can be supplied into the combustion chamber 500 through the high-pressure hydrogen injector 110, so that a lean mixture having a homogeneous equivalent air-fuel ratio of more than 2 can be formed in the combustion chamber 500. Compared with a conventional porous (more than or equal to 2 holes) injector of an internal combustion engine directly injecting hydrogen, the high-pressure hydrogen injector 110 of the lean combustion system provided by the invention has the advantages that the contact area of hydrogen and air can be enlarged, the rapid and uniform mixing of hydrogen and air is promoted, and the low emission and even zero emission of NOx can be realized.
In order to achieve the above idea, based on the same inventive concept, the present invention further provides a lean-burn engine including at least one of the lean-burn systems according to the above embodiments. Specifically, the lean-burn engine includes at least one cylinder, and the lean-burn system according to the above embodiment is provided for each cylinder, so that lean combustion can be achieved in each cylinder. The lean-burn engine provided by the invention has all the advantages of the lean-burn system because the lean-burn engine comprises at least one lean-burn system, namely, the lean-burn engine provided by the invention adopts the umbrella-shaped spray injector as the high-pressure hydrogen injector, and compared with a conventional porous (more than or equal to 2 holes) injector of an internal combustion engine which directly injects hydrogen in a cylinder, the lean-burn engine can enlarge the contact area of hydrogen and air, promote the rapid and uniform mixing of the hydrogen and the air, and further realize the low emission and even zero emission of NOx.
In order to achieve the above idea, based on the same inventive concept, the present invention also provides a lean combustion method applied to the lean combustion engine described in the above embodiment. According to the lean combustion method provided by the invention, the lean combustion of the uniform mixture is realized by controlling the air inlet time of the air inlet unit, the injection time of the high-pressure injection unit and the ignition time of the ignition unit in one working cycle.
Referring to fig. 3, a schematic diagram of the operating condition of the engine according to an embodiment of the present invention is schematically shown, as shown in fig. 3, where a region I is a low load condition, a region ii is a medium load condition, and a region iii is a high load condition. The combustion strategies employed by these three regions are described in detail below.
Referring to fig. 4, a schematic diagram of the control strategy of air intake, high pressure hydrogen injection and ignition under low load conditions according to an embodiment of the present invention is schematically shown. As shown in FIG. 4, under the low load condition of the region I, the lean combustion method is as follows:
for one duty cycle, after a period of time following the beginning of the intake stroke, initiating direct injection of an umbrella-shaped hydrogen spray through the high pressure hydrogen injector into the combustion chamber.
As shown in figure 4, under the low-load working condition, the ultra-lean mixture in the combustion chamber is mainly realized by umbrella-shaped spray and long mixing time, the high-pressure hydrogen injection starting moment occurs after the intake valve is opened for a period of time, the whole high-pressure hydrogen injection phase occurs in the intake stroke phase, and the ignition starting moment occurs in the last stage of the compression stroke, so that the temperature in the combustion chamber can be ensured to be lower than the self-ignition temperature of the hydrogen, and before ignition, the mixing time of the hydrogen and the air is long enough, so that the uniform mixing of the hydrogen and the air can be ensured, and the occurrence of backfire and pre-ignition can be effectively avoided. In addition, the high-pressure hydrogen injector sprays umbrella-shaped hydrogen, so that the contact area of the hydrogen and the air can be enlarged, and the uniform and rapid mixing of the hydrogen and the air is promoted.
Referring to fig. 5, a schematic diagram of an intake, high pressure hydrogen injection and ignition control strategy under medium load conditions according to an embodiment of the present invention is schematically shown. As shown in FIG. 5, under the medium load condition of the region II, the lean combustion method comprises the following steps:
for one working cycle, at the end of the intake stroke, an umbrella-shaped hydrogen spray is started to be directly injected into the combustion chamber through the high-pressure hydrogen injector.
As can be seen from a comparison between fig. 4 and 5, in the medium load condition, the strategy of homogeneous lean combustion is still adopted, but unlike the low load condition, the injection timing of the umbrella-shaped hydrogen gas spray is appropriately retarded according to the change of the rotational speed load in the medium load condition. As shown in fig. 4 and 5, in the medium load condition, the high pressure hydrogen injection starts at the end of the intake stroke and ends at the compression stroke. This is because the injection of hydrogen gas during the intake stroke results in a decrease in the charging efficiency of fresh air, and as the load increases, it becomes more and more difficult to achieve the target of an appropriate air-fuel ratio greater than 2, and the demand for a supercharging system (turbo-charging or mechanical-charging) becomes higher and higher. Therefore, under the medium-load working condition, the start moment of hydrogen injection is delayed, the air charging efficiency can be increased, and the aim that the equivalent air-fuel ratio of homogeneous mixture is larger than 2 is fulfilled.
Referring to fig. 6, a schematic diagram of an intake, high pressure hydrogen injection and ignition control strategy under high load conditions according to an embodiment of the present invention is schematically shown. As shown in fig. 6, in the high load condition of the region iii, the lean combustion method is:
and for one working cycle, after the air inlet valve is closed, injecting umbrella-shaped hydrogen spray into the combustion chamber at least twice through the high-pressure hydrogen injector, and igniting once through the ignition unit, wherein the first injection of the umbrella-shaped hydrogen spray occurs before ignition, and the last injection of the umbrella-shaped hydrogen spray occurs after ignition.
As shown in fig. 6, in the high load condition, the strategy of multiple hydrogen injections in the compression stroke and the expansion stroke is adopted to realize the multi-stage exothermic combustion, because the short quenching distance of hydrogen makes the heat transfer loss a key factor for restricting the improvement of the thermal efficiency in the high load condition. The key point of reducing the high-load heat transfer loss is to reduce the contact of hydrogen and the wall surface of the combustion chamber, and therefore, under the high-load working condition, the purpose of reducing the heat transfer loss is realized by adopting a multi-injection strategy. Preferably, the time interval between the ignition start time and the injection start time of the last umbrella-shaped hydrogen gas spray is 0 to 20 crank angle degrees.
As shown in fig. 6, in the present embodiment, three high-pressure hydrogen injections, all of which occur after the intake valve is closed, are performed for one duty cycle to obtain the maximum air charging efficiency. The first high-pressure hydrogen injection is main injection, namely most of hydrogen is injected at the time so as to ensure enough mixing time of the hydrogen and air. The second high-pressure hydrogen injection occurs before or during ignition, the third high-pressure hydrogen injection occurs after ignition, the time interval from the ignition start timing of the second high-pressure hydrogen injection is defined as Δ 1 (crank angle), and the time interval from the ignition start timing of the third high-pressure hydrogen injection is defined as Δ 2 (crank angle). Preferably, Δ 1 and Δ 2 are 0 to 20 crank angle degrees. Preferably, ignition is carried out during the second high-pressure hydrogen injection, so that residual hydrogen in the second high-pressure hydrogen injection and hydrogen in the third high-pressure hydrogen injection can be directly injected into the generated hydrogen flame, and the contact between the hydrogen and the wall surface of the combustion chamber is avoided, thereby greatly reducing heat transfer loss and improving heat efficiency.
Referring to fig. 7, a schematic diagram of an intake, high pressure hydrogen injection and ignition control strategy under high load conditions according to another embodiment of the present invention is schematically shown. As shown in fig. 7, in the high load condition of the region iii, the lean combustion method is:
and for one working cycle, after the closing of the intake valve, injecting umbrella-shaped hydrogen spray into the combustion chamber at least twice through the high-pressure hydrogen injector, and igniting twice through the ignition unit, wherein the first umbrella-shaped hydrogen spray is injected before the first ignition is started, and the last umbrella-shaped hydrogen spray is injected in the time period from the first ignition to the second ignition or in the second ignition period.
As can be seen from a comparison between fig. 6 and 7, in the present embodiment, a multiple hydrogen injection strategy is also employed, and as shown in fig. 7, in the present embodiment, three high-pressure hydrogen injections are performed for one operation cycle, and all of the three high-pressure hydrogen injections occur after the intake valve is closed. The present embodiment is different from the previous embodiment in that in the present embodiment, ignition is performed once during or after the third high-pressure hydrogen injection, and the time interval from the second ignition start timing to the third injection start timing is defined as Δ 3 (crank angle). Preferably, Δ 3 is 0 to 20 crank angle degrees. In this embodiment, by providing the second ignition, the hydrogen remaining due to the incomplete combustion in the second high-pressure hydrogen injection and the third high-pressure hydrogen injection can be further sufficiently combusted, thereby effectively improving the combustion efficiency.
Referring to fig. 8, which schematically shows a comparison between the multi-stage heat release strategy of the present invention and the conventional single-stage heat release strategy, it can be seen from fig. 8 that the present invention can reduce the peak maximum heat release rate and prolong the heat release time by using the multi-stage heat release strategy under high load conditions, thereby contributing to the reduction of the in-cylinder combustion temperature and ultimately the reduction of NOx generation.
It should be noted that, under high load conditions, the high-pressure hydrogen injection may be performed two times, four times or other times after the intake valve is closed, and the present invention is not limited thereto.
In summary, compared with the prior art, the lean combustion system, the method and the engine provided by the invention have the following advantages:
(1) the invention provides a lean combustion system which comprises a high-pressure injection unit, an ignition unit, an air inlet unit, an exhaust unit, a combustion chamber and a piston, wherein the high-pressure injection unit is connected with the ignition unit; the piston is reciprocable within the combustion chamber; the high-pressure injection unit, the ignition unit, the air inlet unit and the exhaust unit are all arranged at the top of the combustion chamber; the high-pressure injection unit comprises a high-pressure hydrogen injector, the high-pressure hydrogen injector is an umbrella-shaped spray oil injector, and the high-pressure hydrogen injector is used for directly injecting umbrella-shaped hydrogen spray to the combustion chamber; the air inlet unit comprises an air inlet valve and an air inlet channel which are connected, and the combustion chamber is communicated with the outside atmosphere through the air inlet unit; the exhaust unit comprises an exhaust valve and an exhaust passage which are connected, and the combustion chamber is communicated with the outside atmosphere through the exhaust unit; the ignition unit is used for burning fuel in the combustion chamber. Therefore, fresh air can be input into the combustion chamber through the air inlet unit, high-pressure umbrella-shaped hydrogen spray can be input into the combustion chamber through the high-pressure hydrogen injector, and therefore a uniform lean mixture with the equivalent air-fuel ratio larger than 2 can be formed in the combustion chamber. Compared with a conventional porous (more than or equal to 2 holes) injector of an internal combustion engine directly injecting hydrogen in a cylinder, the lean combustion system provided by the invention can enlarge the contact area of hydrogen and air and promote the rapid and uniform mixing of hydrogen and air by adopting the umbrella-shaped spray oil injector as a high-pressure hydrogen injector, thereby realizing the low emission and even zero emission of NOx.
(2) The lean-burn engine provided by the invention has all the advantages of the lean-burn system because the lean-burn engine comprises at least one lean-burn system, namely, the lean-burn engine provided by the invention adopts the umbrella-shaped spray injector as the high-pressure hydrogen injector, and compared with a conventional porous (more than or equal to 2 holes) injector of an internal combustion engine which directly injects hydrogen in a cylinder, the lean-burn engine can enlarge the contact area of hydrogen and air, promote the rapid and uniform mixing of the hydrogen and the air, and further realize the low emission and even zero emission of NOx.
(3) The invention provides a lean combustion method, which comprises the following steps: under the low-load working condition, aiming at one working cycle, after a period of time from the beginning of an intake stroke, directly injecting umbrella-shaped hydrogen spray to the combustion chamber through the high-pressure hydrogen injector; under the medium-load working condition, aiming at one working cycle, at the end of an intake stroke, directly injecting umbrella-shaped hydrogen spray to the combustion chamber through the high-pressure hydrogen injector; under the high-load working condition, after an air inlet valve is closed, the high-pressure hydrogen injector injects umbrella-shaped hydrogen to the combustion chamber at least twice, and the ignition unit ignites once, wherein the first injection of the hydrogen spray occurs before ignition, the last injection of the hydrogen spray occurs after ignition, or under high load conditions, for one duty cycle, after the air inlet valve is closed, the high-pressure hydrogen injector injects umbrella-shaped hydrogen spray into the combustion chamber at least twice, and the ignition unit ignites twice, wherein the first injection of the hydrogen spray occurs before the first ignition begins and the last injection of the hydrogen spray occurs during a period of time after the first ignition and before the second ignition or during the second ignition. Therefore, the hydrogen injection strategy adopted by the lean combustion method under medium and low loads can realize the stable combustion of the uniform lean mixture with equivalent air-fuel ratio more than 2, thereby achieving the purpose of low or even zero NOx emission; the hydrogen multi-injection strategy adopted under high load can realize multi-stage heat release combustion, and reduce the emission of NOx while improving the heat efficiency.
The above description is only for the purpose of describing the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention, and any variations and modifications made by those skilled in the art based on the above disclosure are within the scope of the appended claims. It will be apparent to those skilled in the art that various changes and modifications may be made in the invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (15)
1. A lean combustion system is characterized by comprising a high-pressure injection unit, an ignition unit, an air inlet unit, an exhaust unit, a combustion chamber and a piston;
the piston is reciprocable within the combustion chamber;
the high-pressure injection unit, the ignition unit, the air inlet unit and the exhaust unit are all arranged at the top of the combustion chamber;
the high-pressure injection unit comprises a high-pressure hydrogen injector, the high-pressure hydrogen injector is an umbrella-shaped spray oil injector, and the high-pressure hydrogen injector is used for directly injecting umbrella-shaped hydrogen spray to the combustion chamber;
the air inlet unit comprises an air inlet valve and an air inlet channel which are connected, and the combustion chamber is communicated with the outside atmosphere through the air inlet unit;
the exhaust unit comprises an exhaust valve and an exhaust passage which are connected, and the combustion chamber is communicated with the outside atmosphere through the exhaust unit;
the ignition unit is used for burning fuel in the combustion chamber.
2. The lean burn system of claim 1 wherein the intake unit further comprises an intake valve lift mechanism for continuously varying an opening timing of an intake valve, and the exhaust unit further comprises an exhaust valve lift mechanism for continuously varying an opening timing of an exhaust valve.
3. The lean burn system of claim 1 wherein the ignition unit comprises an ignition coil and a spark plug connected.
4. The lean burn system of claim 3 wherein the umbrella-shaped hydrogen spray injected by the high pressure hydrogen injector is directed to a location proximate the spark plug.
5. The lean burn system of claim 1 wherein the high pressure hydrogen injector and the ignition unit are both located between the intake unit and the exhaust unit, the ignition unit being located proximate to the exhaust unit.
6. The lean combustion system of claim 1, wherein the high pressure injection unit further comprises a high pressure hydrogen storage device, a pressure control valve and a high pressure hydrogen rail which are connected in sequence, and an air outlet of the high pressure hydrogen rail is connected with an air inlet of the high pressure hydrogen injector.
7. The lean burn system of claim 1 wherein the high pressure hydrogen injector has an injection pressure of no less than 30 bar.
8. The lean burn system of claim 1 wherein the high pressure hydrogen injector is an open ring injector or a swirl type injector.
9. The lean-burn system of claim 1 wherein the piston is a high compression ratio piston.
10. The lean burn system of claim 1 wherein the intake unit is located on one side of the top of the combustion chamber and the exhaust unit is located on the other side of the top of the combustion chamber, the high pressure hydrogen injector being located near an intermediate position of the top of the combustion chamber.
11. A lean-burn engine comprising at least one lean-burn system as claimed in any one of claims 1 to 10.
12. A lean combustion method applied to the lean combustion engine according to claim 11, the lean combustion method comprising:
under the low-load working condition, aiming at one working cycle, after a period of time from the beginning of an intake stroke, directly injecting umbrella-shaped hydrogen spray to the combustion chamber through the high-pressure hydrogen injector;
under the medium-load working condition, aiming at one working cycle, at the end of an intake stroke, directly injecting umbrella-shaped hydrogen spray to the combustion chamber through the high-pressure hydrogen injector;
and under a high-load working condition, after an intake valve is closed, injecting umbrella-shaped hydrogen spray into the combustion chamber at least twice through the high-pressure hydrogen injector and igniting once through the ignition unit, wherein the first injection of the umbrella-shaped hydrogen spray occurs before ignition and the last injection of the umbrella-shaped hydrogen spray occurs after ignition.
13. The lean combustion method as claimed in claim 12, wherein at high load conditions, at least two injections of an umbrella-shaped hydrogen gas spray are made into the combustion chamber by the high-pressure hydrogen injector after the intake valve is closed, and two ignitions are made by the ignition unit, wherein the first injection of the umbrella-shaped hydrogen gas spray occurs before the first ignition is started, and the last injection of the umbrella-shaped hydrogen gas spray occurs in the period from after the first ignition to before the second ignition or during the second ignition, for one working cycle.
14. The lean burn method of claim 12, wherein the time interval from the ignition start to the injection start of the last umbrella-shaped hydrogen spray is 0 to 20 crank angle degrees under high load conditions.
15. The lean combustion method as claimed in claim 13, wherein, in the high load condition, the time interval from the first ignition start time to the last injection start time of the umbrella-shaped hydrogen gas spray is 0 to 20 crank angle degrees, and the time interval from the last injection start time of the umbrella-shaped hydrogen gas spray to the second ignition start time is 0 to 20 crank angle degrees.
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| CN114320625A (en) * | 2021-12-31 | 2022-04-12 | 中国第一汽车股份有限公司 | Control method and system for hydrogen injection of engine, processor and electronic device |
| WO2023152295A1 (en) * | 2022-02-10 | 2023-08-17 | Dma Tech S.À R.L. | Hydrogen-fueled four-stroke internal combustion engine |
| LU501822B1 (en) * | 2022-04-08 | 2023-10-09 | Dma Tech S A R L | Hydrogen-fueled four-stroke internal combustion engine |
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