Multi-injection system integrating methanol and cracked gas thereof

Abstract

The invention belongs to the related technical field of methanol hydrogen engines, and discloses a methanol and cracked gas integrated multi-injection system which comprises a methanol engine assembly, a methanol fuel tank, a methanol cracker, a methanol high-pressure pipeline, a methanol low-pressure pipeline and a methanol cracked gas pipeline, the methanol engine assembly comprises a methanol hydrogen ejector; one end of the methanol high-pressure pipeline is connected with a first outlet of the methanol fuel tank, and the other end is connected with an inlet I of the methanol hydrogen ejector; one end of the methanol low-pressure pipeline is connected with a second outlet of the methanol fuel tank, and the other end is connected with an inlet of the methanol cracker; one end of the methanol cracking gas pipeline is connected with an outlet of the methanol cracker, and the other end is connected with an inlet II of the alcohol-hydrogen ejector. Accurate control over the amount of cracked gas entering a cylinder is achieved, the injection amount is adjusted according to parameter changes of mixed gas in the cylinder, simultaneous or independent injection of methyl alcohol and cracked gas of the methyl alcohol is achieved through the alcohol-hydrogen injector, and different fuel control modes can be adopted according to different working conditions.

Description

Technical Field

[0001] The present invention belongs to the technical field related to alcohol-hydrogen engines, and relates to a multiple injection system integrating methanol and its cracked gas. More specifically, it relates to a multiple fuel injection system that utilizes a gas-liquid two-phase dual-fluid injector to achieve simultaneous or independent injection of methanol and its cracked gas, and provides fuel organization methods under different loads. Background Art

[0002] Under the global trend of reducing carbon emissions, methanol has received widespread attention as a highly potential alternative fuel for engines. Since methanol contains 50% oxygen, it helps the fuel burn fully and improves the thermal efficiency of the engine. Methanol is also a hydrogen energy carrier that can use the engine's waste heat to produce hydrogen, thus solving the problem of hydrogen being difficult to store. In addition, methanol is cheaper than fuel oil, so it has better fuel economy.

[0003] Alcohol-hydrogen engine refers to the process of using the waste heat of engine exhaust to crack methanol into hydrogen-rich methanol cracking gas under the action of a catalyst, and then passing it into the combustion chamber for combustion. This technology recovers part of the waste heat of exhaust, and hydrogen can accelerate combustion and increase the combustion isochoricity, thereby improving the thermal efficiency of the engine. Therefore, alcohol-hydrogen engine provides an effective technical path and solution for reducing carbon emissions and responding to climate change.

[0004] In the prior art, there are two main fuel supply methods for alcohol-hydrogen engines: one is direct injection of methanol into the cylinder, and the cracking gas is injected through the intake duct; the other is that methanol and methanol cracking gas are sprayed into the cylinder through two independent nozzles in the intake duct. The above methods all require two nozzles. The dual-nozzle injection system increases the complexity of the engine structure, increases the manufacturing cost and the difficulty of maintenance. In addition, there are technical problems such as the wear resistance and corrosion resistance of the nozzle, and the inability to accurately control the amount of cracking gas entering the cylinder. Therefore, it is urgent to propose a multiple injection system that integrates methanol and its cracking gas, which can spray methanol and cracking gas into the cylinder simultaneously or independently through direct injection into the cylinder, simplify the installation structure, and achieve accurate control of the amount of cracking gas entering the cylinder. Summary of the invention

[0005] In view of the above defects or improvement needs of the prior art, the present invention provides a multiple injection system integrating methanol and its cracked gas, with the purpose of streamlining the structure of the fuel supply system, optimizing the layout space, achieving precise control of the amount of cracked gas entering the cylinder, and adjusting the injection amount according to changes in the parameters of the mixed gas in the cylinder, thereby solving the technical problems of the complex structure of the dual-nozzle injection system and the need for precise control of the amount of cracked gas.

[0006] To achieve the above-mentioned purpose, according to one aspect of the present invention, a multiple injection system integrating methanol and its cracked gas is provided, comprising: a methanol engine assembly, a methanol fuel tank 4, a methanol cracker 12, a methanol high-pressure pipeline, a methanol low-pressure pipeline, and a methanol cracked gas pipeline; the methanol engine assembly comprises an alcohol hydrogen injector 2; one end of the methanol high-pressure pipeline is connected to the first outlet of the methanol fuel tank 4, and the other end is connected to the inlet one of the alcohol hydrogen injector 2; one end of the methanol low-pressure pipeline is connected to the second outlet of the methanol fuel tank 4, and the other end is connected to the inlet of the methanol cracker 12; one end of the methanol cracked gas pipeline is connected to the outlet of the methanol cracker 12, and the other end is connected to the inlet two of the alcohol hydrogen injector 2.

[0007] Preferably, a methanol high-pressure pump 5, a methanol flowmeter 6, a methanol supply quantity control valve 7 and a methanol high-pressure common rail 8 are sequentially arranged on the methanol high-pressure pipeline along the gas flow direction; the methanol high-pressure pipeline is used to provide methanol to the alcohol hydrogen injector 2.

[0008] Preferably, a methanol low-pressure pump 9, a methanol cracking amount control valve 10 and a methanol flowmeter 11 are sequentially arranged on the methanol low-pressure pipeline along the gas flow direction; the methanol low-pressure pipeline is used to supply the methanol required for cracking to the methanol cracker 12.

[0009] Preferably, a booster pump 13, a pressure stabilizer 14, a cracking gas flow meter 15, a cracking gas flow control valve 16, and a cracking gas high-pressure common rail 17 are sequentially arranged on the methanol cracking gas pipeline along the gas flow direction; the methanol cracking gas pipeline is used to provide methanol cracking gas to the alcohol hydrogen injector 2.

[0010] Preferably, the methanol engine assembly also includes an intake duct 1, a combustion chamber, a cylinder head, a spark plug 3, and an exhaust duct 19. The alcohol hydrogen injector 2 and the spark plug 3 are installed on the cylinder head. The alcohol hydrogen injector 2 is used to inject methanol and methanol cracked gas simultaneously or separately for multiple times, and the spark plug 3 is used to ignite the cracked gas or methanol or a mixture of methanol and its cracked gas.

[0011] Preferably, the alcohol hydrogen injector 2 is provided with a methanol channel 22 , a cracked gas channel 21 , a cracked gas spray hole 23 , and a methanol spray hole 24 ; the cracked gas channel 21 is located outside the methanol channel 22 and is independent of each other; the methanol spray hole 24 is located below the cracked gas spray hole 23 .

[0012] Preferably, the high-temperature exhaust gas of the methanol engine assembly enters the methanol cracker 12 through the exhaust passage 19 , and enters the exhaust passage 19 again after sufficient heat exchange with methanol; a cracker safety valve 18 is installed on the methanol cracker 12 .

[0013] Preferably, the methanol high-pressure pump 5 pumps methanol into the methanol high-pressure common rail 8, the methanol flowmeter 6 is used to detect the real-time flow of methanol, and the methanol supply control valve 7 adjusts the flow of methanol entering the methanol high-pressure common rail 8 according to the current load of the engine, thereby changing the rail pressure of the methanol high-pressure common rail 8.

[0014] Preferably, the methanol low-pressure pump 9 pumps methanol into the methanol cracker 12, the methanol cracking amount control valve 10 is used to control the amount of methanol entering the methanol cracker 12; the methanol flowmeter 11 is used to detect the amount of methanol entering the methanol cracker 12.

[0015] Preferably, the boost pump 13 is used to increase the pressure of the methanol cracking gas at the outlet of the methanol cracker 12, thereby increasing the pressure in the regulator 14; the regulator 14 is used to stabilize the pressure of the methanol cracking gas and has the function of storing a portion of the methanol cracking gas; the cracking gas flow meter 15 is used to detect the flow rate of the methanol cracking gas, and the cracking gas flow control valve 16 adjusts the flow rate of the methanol cracking gas entering the cracking gas high-pressure common rail 17 according to the current load of the engine, and controls the injection amount of the methanol cracking gas through the alcohol hydrogen injector 2.

[0016] In general, compared with the prior art, the above technical solution conceived by the present invention provides a multiple injection system integrating methanol and its cracked gas, which mainly has the following beneficial effects:

[0017] 1. Compared with the injection of methanol cracking gas in the intake duct, the present invention realizes the precise control of the amount of cracking gas entering the cylinder, and adjusts the injection amount according to the change of the mixed gas parameters in the cylinder. Utilizing the characteristics of the alcohol hydrogen injector, the simultaneous injection of methanol cracking gas and methanol helps to atomize methanol, forming a uniform methanol-cracked gas-air mixture, and different fuel organization methods can be adopted for different working conditions. Since the alcohol hydrogen injector is installed on the cylinder head and directly injected into the combustion chamber, the amount of cracking gas entering the combustion chamber can be accurately controlled, achieving a more accurate match of the cracking gas demand under different working conditions, improving the stability of engine operation, and avoiding the influence of gas fuel on the filling coefficient.

[0018] 2. The present invention simplifies the structure of the fuel supply system and optimizes the layout space; a single alcohol hydrogen injector is used to realize the simultaneous or independent injection of methanol and its cracking gas, which saves its installation area on the cylinder head, simplifies the installation structure and difficulty, and improves reliability.

[0019] 3. The voltage stabilizer of the present invention has the function of storing cracked gas. Since the cracked gas contains a part of hydrogen, it is easier to ignite than methanol. When the engine is cold-started, the engine can be cold-started by only injecting methanol cracked gas, without the need for an additional heating device.

[0020] 4. The invention proposes a multiple injection system integrating methanol and its cracked gas, which is suitable for fuel organization and combustion control under medium, low and high load conditions. Under medium and low loads, as much cracked gas as possible is blended and burned, and premixed-diffusion combustion is achieved by multiple injections of methanol to improve combustion efficiency; under high loads, the amount of cracked gas blended is reduced, combined with multiple injections, to effectively reduce the risk of knock and ensure stable operation of the engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of a multiple injection system integrating methanol and its cracked gas of the present invention;

[0022] Figure 2 It is a structural schematic diagram of the alcohol hydrogen injector.

[0023] In all the drawings, the same reference numerals are used to represent the same elements or structures, including: engine intake duct 1, alcohol hydrogen injector 2, cracked gas channel 21, methanol channel 22, cracked gas spray hole 23, methanol spray hole 24, spark plug 3, methanol fuel tank 4, methanol high-pressure pump 5, methanol flow meter 1 6, methanol flow control valve 7, methanol high-pressure common rail 8, methanol low-pressure pump 9, methanol cracking amount control valve 10, methanol flow meter 2 11, methanol cracker 12, boost pump 13, stabilizer 14, cracked gas flow meter 15, cracked gas flow control valve 16, cracked gas high-pressure common rail 17, cracker safety valve 18, exhaust duct 19. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0025] See also Figure 1 The present invention provides a multiple injection system integrating methanol and its cracked gas, comprising: a methanol engine assembly, a methanol fuel tank 4, a methanol cracker 12, a methanol high-pressure pipeline, a methanol low-pressure pipeline, and a methanol cracked gas pipeline; the methanol engine assembly comprises an alcohol hydrogen injector 2; one end of the methanol high-pressure pipeline is connected to the first outlet of the methanol fuel tank 4, and the other end is connected to the inlet one of the alcohol hydrogen injector 2; one end of the methanol low-pressure pipeline is connected to the second outlet of the methanol fuel tank 4, and the other end is connected to the inlet of the methanol cracker 12; one end of the methanol cracked gas pipeline is connected to the outlet of the methanol cracker 12, and the other end is connected to the inlet two of the alcohol hydrogen injector 2.

[0026] The methanol engine assembly also includes an intake duct 1, a combustion chamber, a cylinder head, a spark plug 3, and an exhaust duct 19. An alcohol hydrogen injector 2 and a spark plug 3 are installed on the cylinder head. The alcohol hydrogen injector 2 is used to inject methanol and methanol cracked gas simultaneously or separately for multiple times. The spark plug 3 is used to ignite the cracked gas or methanol or a mixture of methanol and its cracked gas.

[0027] A methanol high-pressure pump 5, a methanol flow meter 6, a methanol supply control valve 7 and a methanol high-pressure common rail 8 are sequentially arranged on the methanol high-pressure pipeline along the air flow direction; the methanol high-pressure pipeline is used to supply methanol to the alcohol hydrogen injector 2. The methanol high-pressure pump 5 pumps methanol into the methanol high-pressure common rail 8, the methanol flow meter 6 is used to detect the real-time flow of methanol, and the methanol supply control valve 7 adjusts the flow of methanol entering the methanol high-pressure common rail 8 according to the current load of the engine, thereby changing the rail pressure of the methanol high-pressure common rail 8, and then dynamically adjusts the injection pressure of methanol.

[0028] A methanol low-pressure pump 9, a methanol cracking amount control valve 10 and a methanol flow meter 11 are sequentially arranged on the methanol low-pressure pipeline along the gas flow direction; the methanol low-pressure pipeline is used to supply methanol required for cracking to the methanol cracker 12. The methanol low-pressure pump 9 pumps methanol into the methanol cracker 12, the methanol cracking amount control valve 10 is used to control the amount of methanol entering the methanol cracker 12; the methanol flow meter 11 is used to detect the amount of methanol entering the methanol cracker 12. A control unit is arranged in the engine assembly to control the methanol cracking amount control valve 10 according to the cracking amount required for different working conditions and the current cracking amount.

[0029] A booster pump 13, a stabilizer 14, a cracking gas flow meter 15, a cracking gas flow control valve 16, and a cracking gas high-pressure common rail 17 are sequentially arranged on the methanol cracking gas pipeline along the gas flow direction; the methanol cracking gas pipeline is used to provide methanol cracking gas to the alcohol hydrogen injector 2. The booster pump 13 is used to increase the pressure of the methanol cracking gas at the outlet of the methanol cracker 12, thereby increasing the pressure in the stabilizer 14; the stabilizer 14 is used to stabilize the pressure of the methanol cracking gas and has the function of storing a part of the methanol cracking gas; the cracking gas flow meter 15 is used to detect the flow of the cracking methanol cracking gas, and the cracking gas flow control valve 16 adjusts the flow of the methanol cracking gas entering the cracking gas high-pressure common rail 17 according to the current load of the engine, and controls the injection amount of the methanol cracking gas through the alcohol hydrogen injector 2. Specifically, the methanol cracking gas generated by the methanol cracker 12 is pressurized to the rail pressure of the cracking gas high-pressure common rail 17 through the booster pump 13, and then enters the stabilizer 14 to stabilize the pressure of the cracking gas. The rail pressure of the cracking gas high-pressure common rail 17 can be set to about 5MPa. The pressurized methanol cracking gas is adjusted to a suitable injection amount by the alcohol hydrogen injector 2 according to the working condition of the engine. The voltage stabilizer 14 also has the function of storing the methanol cracking gas: when the engine is stopped, since the exhaust temperature is still high, a part of the methanol cracking gas will be generated. At this time, the boost pump 13 still keeps working, and a part of the methanol cracking gas is stored in the voltage stabilizer 14 for the cold start of the engine.

[0030] A methanol channel 22, a cracking gas channel 21, a cracking gas spray hole 23, and a methanol spray hole 24 are arranged in the alcohol hydrogen injector 2; the cracking gas channel 21 is located outside the methanol channel 22 and is independent of each other; the methanol spray hole 24 is located below the cracking gas spray hole 23, and uses high-speed gas injection to guide the methanol spray to move toward the piston to prevent the methanol spray from moving toward the cylinder head and adhering to the cylinder head, causing incomplete combustion. The high-temperature exhaust gas of the methanol engine assembly enters the methanol cracker 12 through the exhaust duct 19, and enters the exhaust duct 19 again after sufficient heat exchange with methanol. A cracker safety valve 18 is installed on the methanol cracker 12. When the pressure of the methanol cracker 12 is higher than the safety value, the cracker safety valve 18 opens to maintain the pressure within a safe range.

[0031] In this embodiment, the working process of a multiple injection system integrating methanol and its cracked gas provided by the present invention under different engine operating conditions is as follows:

[0032] During cold start of the engine, methanol is not easily ignited when sprayed into the cylinder due to the large latent heat of methanol vaporization. Therefore, during cold start of the engine, the alcohol hydrogen injector 2 sprays methanol cracking gas into the cylinder after the intake duct 1 is completely closed to ensure that the methanol cracking gas and air are fully mixed. The spark plug 3 ignites near the top dead center to ignite the cracking gas-air premixed gas to achieve premixed combustion. The ignition advance angle can be set to 20-30°CA, which is determined specifically according to the engine model.

[0033] When the engine is at a medium or low load, the engine determines the ratio of cracking gas to be blended according to the specific load. Specifically, in order to improve the economy of the engine, as much cracking gas as possible can be blended under the premise of ensuring stability. Methanol and methanol cracking gas are sprayed at the same time. Since the cracking gas spray hole 23 is located above the methanol spray hole 24, when both are sprayed at the same time, the methanol cracking gas helps methanol to be further atomized, forming a uniform methanol-cracking gas-air premixed gas, and realizing rapid combustion. When the piston moves to near the top dead center, the spark plug 3 ignites. Specifically, compared with the cold start, the ignition advance angle should be reduced. In order to prevent the pressure increase rate of the mixed gas from being too large after ignition, a small amount of methanol is sprayed again after ignition to realize the diffusion combustion of methanol. The methanol injected for the second time also has a large latent heat of vaporization, which can reduce the combustion temperature and reduce NOx emissions. Since premixed combustion has a faster flame propagation speed and the engine knock tendency is lower under medium and low loads, the proportion of methanol premixed combustion can be increased. Specifically, the ratio of the amount of methanol injected during the premixing process to the amount of methanol injected for the second time can be more in the front and less in the back.

[0034] When the engine is under high load, the combustion is more intense, and the methanol cracking gas contains more hydrogen, which will increase the engine knock tendency, so the proportion of blending is reduced accordingly, and the premixed combustion ratio should also be reduced. Specifically, in order to ensure sufficient premixing time, the cracking gas injection advance angle is increased and the ignition advance angle is reduced to avoid excessive pressure gradient in the combustion chamber. Although the preferred embodiment of the present invention is described with double injection as an example, it should be understood by those skilled in the art that similar technical effects can be achieved by appropriately adjusting the number of injections (such as three or more times). For example, further injecting an appropriate amount of methanol in the late combustion period can effectively improve the combustion characteristics of the afterburning period.

[0035] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A multiple injection system integrating methanol and its cracked gas, characterized in that: include: Methanol engine assembly, methanol fuel tank (4), methanol cracker (12), methanol high-pressure pipeline, methanol low-pressure pipeline, methanol cracking gas pipeline; The methanol engine assembly comprises an alcohol hydrogen injector (2); one end of the methanol high-pressure pipeline is connected to the first outlet of the methanol fuel tank (4), and the other end is connected to the first inlet of the alcohol hydrogen injector (2); one end of the methanol low-pressure pipeline is connected to the second outlet of the methanol fuel tank (4), and the other end is connected to the inlet of the methanol cracker (12); one end of the methanol cracked gas pipeline is connected to the outlet of the methanol cracker (12), and the other end is connected to the second inlet of the alcohol hydrogen injector (2).

2. A multiple injection system integrating methanol and its cracked gas as claimed in claim 1, characterized in that: A methanol high-pressure pump (5), a methanol flow meter (6), a methanol supply quantity control valve (7) and a methanol high-pressure common rail (8) are arranged in sequence on the methanol high-pressure pipeline along the gas flow direction; the methanol high-pressure pipeline is used to supply methanol to the alcohol hydrogen injector (2).

3. A multiple injection system integrating methanol and its cracked gas as claimed in claim 1, characterized in that: A methanol low-pressure pump (9), a methanol cracking amount control valve (10) and a second methanol flow meter (11) are sequentially arranged on the methanol low-pressure pipeline along the gas flow direction; the methanol low-pressure pipeline is used to supply the methanol required for cracking to the methanol cracker (12).

4. A multiple injection system integrating methanol and its cracked gas as claimed in claim 1, characterized in that: A booster pump (13), a voltage stabilizer (14), a cracked gas flow meter (15), a cracked gas flow control valve (16), and a cracked gas high-pressure common rail (17) are sequentially arranged on the methanol cracked gas pipeline along the gas flow direction; the methanol cracked gas pipeline is used to provide methanol cracked gas to the alcohol hydrogen injector (2).

5. A multiple injection system integrating methanol and its cracked gas as claimed in claim 1, characterized in that: The methanol engine assembly also includes an intake duct (1), a combustion chamber, a cylinder head, a spark plug (3), and an exhaust duct (19). The alcohol hydrogen injector (2) and the spark plug (3) are installed on the cylinder head. The alcohol hydrogen injector (2) is used to inject methanol and methanol cracked gas simultaneously or separately for multiple times. The spark plug (3) is used to ignite the cracked gas or methanol or a mixture of methanol and its cracked gas.

6. A multiple injection system integrating methanol and its cracked gas as claimed in claim 1, characterized in that: The alcohol hydrogen injector (2) is provided with a methanol channel (22), a cracked gas channel (21), a cracked gas spray hole (23), and a methanol spray hole (24); the cracked gas channel (21) is located outside the methanol channel (22) and is independent of each other; the methanol spray hole (24) is located below the cracked gas spray hole (23).

7. A multiple injection system integrating methanol and its cracked gas as claimed in claim 5, characterized in that: The high-temperature exhaust gas of the methanol engine assembly enters the methanol cracker (12) through the exhaust passage (19), and enters the exhaust passage (19) again after sufficient heat exchange with methanol; the methanol cracker (12) is provided with a cracker safety valve (18).

8. A multiple injection system integrating methanol and its cracked gas as claimed in claim 2, characterized in that: The methanol high-pressure pump (5) pumps methanol into the methanol high-pressure common rail (8), the methanol flow meter (6) is used to detect the real-time flow of methanol, and the methanol supply control valve (7) adjusts the flow of methanol entering the methanol high-pressure common rail (8) according to the current load of the engine, thereby changing the rail pressure of the methanol high-pressure common rail (8).

9. A multiple injection system integrating methanol and its cracked gas as claimed in claim 3, characterized in that: The methanol low-pressure pump (9) pumps methanol into the methanol cracker (12); the methanol cracking amount control valve (10) is used to control the amount of methanol entering the methanol cracker (12); and the methanol flow meter 2 (11) is used to detect the amount of methanol entering the methanol cracker (12).

10. A multiple injection system integrating methanol and its cracked gas as claimed in claim 4, characterized in that: The booster pump (13) is used to increase the pressure of the methanol cracking gas at the outlet of the methanol cracker (12), thereby increasing the pressure in the pressure stabilizer (14); the pressure stabilizer (14) is used to stabilize the pressure of the methanol cracking gas and has the function of storing a portion of the methanol cracking gas; the cracking gas flow meter (15) is used to detect the flow of the methanol cracking gas; the cracking gas flow control valve (16) adjusts the flow of the methanol cracking gas entering the cracking gas high-pressure common rail (17) according to the current load of the engine, and controls the injection amount of the methanol cracking gas through the alcohol hydrogen injector (2).

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