Methanol compression ignition engine system and control method of hydrogen-alcohol-ether ternary coupled fuel

Abstract

The present application relates to the technical field of compression ignition engine, and particularly relates to a methanol compression ignition engine system of hydrogen alcohol ether ternary coupled fuel and a control method thereof.The methanol compression ignition engine system comprises a methanol compression ignition engine, a methanol evaporator and a methanol reforming reactor;the methanol reforming reactor is a three-layer cavity structure of radial coaxial nesting, and sequentially comprises a methanol-to-dimethyl ether reforming layer, a methanol-to-hydrogen reforming layer and a nitrogen oxide catalytic reduction layer from inside to outside.Methanol is reformed on line to generate dimethyl ether and hydrogen, and forms hydrogen alcohol ether ternary coupled fuel with unreacted methanol in a premixed fuel storage tank, dimethyl ether assists methanol to realize compression ignition, and hydrogen improves combustion efficiency;engine exhaust gas is used in stages to utilize waste heat, and at the same time, methanol and dimethyl ether are used as a reducing agent to catalytically reduce nitrogen oxides in the engine exhaust gas in situ.The present application integrates fuel reforming and exhaust gas purification functions, realizes flexible adjustment of the distribution ratio of ternary fuel components through regulation and control of a multi-stage electric control flow divider, and is suitable for scenarios such as ships, engineering machinery and distributed power stations.

Description

Technical Field

[0001] This invention relates to the field of compression ignition engine technology, specifically to a methanol compression ignition engine system and control method using hydrogen alcohol ether ternary coupled fuels. Background Technology

[0002] Traditional methanol compression ignition engines typically achieve compression ignition by combining methanol with highly reactive fuels (such as diesel or polyoxymethylene dimethyl ether) or fuel additives (such as 2-ethylhexyl nitrate). Existing patent document CN120197387A discloses a methanol compression ignition engine that uses a dual direct injection system for methanol and diesel to achieve compression ignition; another patent document CN114561234A uses composite fuel additives to increase the cetane number of methanol fuel, ensuring stable ignition in the methanol compression ignition engine. However, both of these technical solutions require the additional introduction of diesel or chemical additives, which not only increases the complexity of the fuel supply system but also prevents the engine from operating cleanly using methanol as the sole fuel. This limits the complete substitution of methanol fuel in compression ignition engines and contradicts the development direction of green and low-carbon technologies.

[0003] Existing methanol online reforming engines mostly only have a separate methanol-to-hydrogen unit to improve combustion characteristics, but they cannot simultaneously solve the dual problems of difficult methanol compression ignition and excessive nitrogen oxide emissions. Although the methanol-to-hydrogen reforming reaction can produce hydrogen to improve the combustion rate and lean-burn limit, hydrogen has an extremely low cetane number, which does not improve ignition performance, and the fundamental problem of difficult methanol compression ignition remains unsolved. Furthermore, the existing systems have separate arrangements for the reforming reactor and exhaust gas aftertreatment device, resulting in low system integration, large space occupation, and unfavorable applications in space-constrained scenarios such as ships and construction machinery. The exhaust gas waste heat is only used for single-stage methanol evaporation; the high-temperature, high-grade exhaust gas still carries a large amount of usable heat energy after heat exchange, but this cannot be utilized in a cascade manner, limiting the overall improvement in energy utilization efficiency.

[0004] Furthermore, the technical solution of using dimethyl ether to ignite methanol requires an additional dimethyl ether storage and supply system, which not only increases system complexity and layout costs, but also prevents this supply system from being reused with the denitrification reducing agent supply system, further exacerbating system redundancy. Conventional multilayer catalytic reactors in the chemical industry are mostly axially co-current or counter-current series structures, with reactants flowing sequentially through each reaction layer along the axial direction. The entire reactor is placed in a fixed temperature environment, making it unsuitable for waste heat utilization scenarios where engine exhaust gas is used for external heating.

[0005] Due to the poor miscibility between fuels, the proportion of methanol directly blended with other fuels is limited, making it difficult to achieve stable operation of a pure compression ignition engine using methanol as the sole fuel. Although methanol engines can achieve near-zero soot emissions, nitrogen oxide emissions still require after-treatment devices to meet emission regulations. In summary, how to achieve stable compression ignition while using methanol as the sole fuel, simultaneously reducing nitrogen oxide emissions, improving the efficiency of exhaust waste heat utilization, and simplifying the system structure remain pressing technical challenges in this field. Summary of the Invention

[0006] The purpose of this invention is to provide a methanol compression ignition engine system and control method using hydrogen alcohol ether ternary coupled fuel, which simultaneously achieves stable compression ignition operation of pure methanol fuel, cascade utilization of exhaust waste heat and efficient purification of nitrogen oxides within a single system.

[0007] To achieve the above objectives, the technical solution of this application is as follows: a methanol compression ignition engine system using hydrogen alcohol ether ternary coupled fuel, comprising a methanol fuel tank, wherein the methanol fuel tank is connected to a methanol reforming pipeline, a methanol premixing pipeline and a methanol direct injection pipeline, wherein the methanol reforming pipeline is connected to a methanol evaporator, the methanol premixing pipeline is connected to a premixed fuel storage tank, and the methanol direct injection pipeline is connected to a methanol direct injection injector, wherein the methanol direct injection injector is installed on the methanol compression ignition engine; The methanol compression ignition engine is connected to an exhaust pipe, which is divided into a first exhaust gas branch and a second exhaust gas branch by an electronically controlled exhaust gas branch. The first exhaust gas branch is connected to a methanol evaporator, and the second exhaust gas branch is connected to the nitrogen oxide catalytic reduction layer of the methanol reforming reactor. The methanol evaporator has two independent passages: one is a methanol passage connecting the methanol inlet and the methanol outlet of the evaporator; the other is an engine exhaust gas passage connecting the exhaust gas inlet and the exhaust gas outlet of the evaporator; the exhaust gas outlet of the evaporator is connected to the nitrogen oxide catalytic reduction layer. The methanol reforming reactor has a radially coaxial nested three-chamber structure, consisting of a methanol-to-dimethyl ether reforming layer, a methanol-to-hydrogen reforming layer, and a nitrogen oxide catalytic reduction layer from the inside out. The high-temperature tail gas in the nitrogen oxide catalytic reduction layer transfers heat inward through the partition wall, providing a heat source for the reforming reactions in the methanol-to-dimethyl ether and methanol-to-hydrogen reforming layers. The purified tail gas from the nitrogen oxide catalytic reduction layer is discharged into the atmosphere through the tail gas outlet of the reforming reactor. The methanol outlet of the evaporator is connected to the inlet of the methanol-to-dimethyl ether (MME) reforming layer and the methanol-to-hydrogen (MHT) reforming layer, respectively. The outlet of the MME reforming layer is connected to the MHT reforming layer. The dimethyl ether mixture generated by the MME reforming layer enters the MHT reforming layer. The mixture containing dimethyl ether and hydrogen generated by the MHT reforming layer is sent to the premixed fuel storage tank. The mixture containing dimethyl ether and hydrogen, together with unreacted methanol, forms a hydrogen-ethanol-ether ternary coupled fuel. The premixed fuel storage tank is connected to the engine intake manifold for combustion in the methanol compression ignition engine. During the compression stroke, dimethyl ether ignites first and then compresses and ignites the premixed mixture containing methanol and hydrogen.

[0008] In another implementation of the present invention, the methanol outlet of the evaporator is divided into a first methanol reforming branch and a second methanol reforming branch via an electrically controlled methanol pipeline splitter. The first methanol reforming branch is connected to the methanol-to-dimethyl ether reforming layer, and the second methanol reforming branch is connected to the methanol-to-hydrogen reforming layer. The methanol pipeline electronically controlled distributor is used to allocate the methanol flow ratio into the methanol-to-dimethyl ether reforming layer and the methanol-to-hydrogen reforming layer, matching the compression ignition requirements and the hydrogen production improvement combustion efficiency requirements under different operating conditions. The flow allocation ratio adjustment range is 1:1 to 10:1.

[0009] In another embodiment of the present invention, the outlet pipeline of the methanol-to-dimethyl ether reforming layer is divided into a first branch and a second branch by an electrically controlled splitter for the methanol reforming product pipeline. The first branch is connected to the methanol-to-hydrogen reforming layer, and the second branch is connected to the nitrogen oxide catalytic reduction layer. The dimethyl ether and water vapor generated in the methanol-to-dimethyl ether reforming layer are partly fed into the methanol-to-hydrogen reforming layer as raw materials for hydrogen production, and partly fed into the nitrogen oxide catalytic reduction layer as nitrogen oxide reducing agent, thus realizing the functional reuse of the reforming products. The electrically controlled splitter in the methanol reforming product pipeline is used to adjust the flow distribution ratio between the first branch and the second branch, with an adjustment range of 100:1 to 20:1.

[0010] In another embodiment of the present invention, the methanol-to-dimethyl ether reforming layer is filled with a methanol-to-dimethyl ether catalyst, the methanol-to-hydrogen reforming layer is filled with a methanol-to-hydrogen catalyst, and the nitrogen oxide catalytic reduction layer is filled with a nitrogen oxide reduction catalyst.

[0011] In another implementation of the present invention, a first electrically controlled methanol flow pump is connected in series on the methanol reforming pipeline, a second electrically controlled methanol flow pump is connected in series on the methanol premixing pipeline, and a third electrically controlled methanol flow pump is connected in series on the methanol direct injection pipeline.

[0012] In another implementation of the present invention, the outlet of the methanol-to-hydrogen reforming layer is connected to a premixed fuel storage tank via a premixed fuel pipeline, and the outlet of the premixed fuel storage tank is connected to the engine intake manifold via a premixed fuel electronically controlled flow pump and a premixed fuel injector in sequence. The engine intake manifold is connected to the outside atmosphere and the engine intake valve.

[0013] The present invention also provides a control method for a methanol compression ignition engine system using the above-mentioned hydrogen alcohol ether ternary coupled fuel, comprising the following steps: Methanol flows out of the methanol tank, passes through the methanol reforming pipeline, and is sent to the methanol evaporator through the methanol inlet of the evaporator. In the heat exchange channel of the methanol evaporator, the methanol evaporates from the liquid phase into the gaseous phase of methanol vapor, and is then sent to the methanol reforming reactor through the methanol outlet of the evaporator. A portion of the methanol vapor enters the methanol-to-dimethyl ether reforming layer, where it undergoes a catalytic dehydration reaction to produce a first mixed product containing dimethyl ether and water vapor. A portion of the first mixed product is fed into the methanol-to-hydrogen reforming layer, where it is reformed with another portion of methanol vapor to generate a second mixed product containing hydrogen. The second mixed product is fed into the premixed fuel storage tank, where it is combined with unreacted methanol to form a hydrogen-ethanol-ether ternary coupled fuel for combustion in the methanol compression ignition engine. Another portion of the first mixed product is fed into the nitrogen oxide catalytic reduction layer; The exhaust gas from the methanol compression ignition engine is divided into two paths. One path is sent to the nitrogen oxide catalytic reduction layer after heat exchange in the methanol evaporator, and the other path is sent directly to the nitrogen oxide catalytic reduction layer. The heat from the exhaust gas is transferred from the outside to the inside through the thermally conductive partition walls of the three-layer chamber, providing a heat source for the reforming reaction of the methanol-to-dimethyl ether reforming layer and the methanol-to-hydrogen reforming layer.

[0014] In another implementation of the present invention, before the methanol is evaporated into gaseous methanol vapor by a methanol evaporator, the method further includes: Methanol is sent into the premixed fuel storage tank via a methanol premixing pipeline, and the methanol ratio in the premixed fuel storage tank is adjusted. Methanol is supplied to the methanol direct injection injector through the methanol direct injection pipeline and injected directly into the cylinder of the methanol compression ignition engine.

[0015] In another implementation of the present invention, the hydrogen alcohol ether ternary coupled fuel in the premixed fuel storage tank is injected into the engine intake manifold via a premixed fuel injector. During the compression stroke, the dimethyl ether spontaneously combusts first and then compresses and ignites the premixed mixture containing methanol and hydrogen.

[0016] In another implementation of the present invention, based on the real-time operating load of the methanol compression ignition engine, the proportion of methanol flow entering the methanol-to-dimethyl ether reforming layer is increased at low load to increase the amount of dimethyl ether produced, and the proportion of methanol flow entering the methanol-to-hydrogen reforming layer is increased at high load to increase the amount of hydrogen produced and to increase the proportion of the first mixed product fed into the nitrogen oxide catalytic reduction layer.

[0017] By adopting the above technical solution, the present invention can achieve the following technical effects: (1) This invention prepares highly active dimethyl ether by online reforming of methanol, and uses the high cetane number and easy self-ignition characteristics of dimethyl ether to assist methanol in achieving compression ignition. This solves the technical problem that existing methanol compression ignition engines need to rely on diesel or additives to achieve ignition, and realizes pure compression ignition operation with methanol as a single fuel, avoiding the complexity of dual fuel systems and the difficulty of fuel addition.

[0018] (2) The present invention utilizes the water vapor generated by the dehydration reaction of methanol to dimethyl ether as the reactant for methanol steam reforming to produce hydrogen, without the need for an additional water vapor supply device, thus solving the problem of external water supply required by the existing hydrogen production system and simplifying the system structure.

[0019] (3) The present invention uses dimethyl ether generated by methanol reforming and unreacted methanol as reducing agents to catalytically reduce nitrogen oxides in the tail gas to nitrogen in situ within the nitrogen oxide catalytic reduction layer. It integrates fuel reforming and tail gas purification functions, and can meet nitrogen oxide emission requirements without additional after-treatment devices, simplifying the structure of the after-treatment system and reducing system costs.

[0020] (4) The present invention adopts a three-layer coaxial nested integrated reactor structure, which realizes the dual synergy of energy and materials: at the energy level, the waste heat of the tail gas is first used for methanol evaporation, and then transferred through the chamber wall to provide heat for the two-stage reforming reaction, realizing the graded and in-depth utilization of waste heat; at the material level, dimethyl ether is used as both the compression ignition active component and the denitrification reducing agent, eliminating the need to set up two separate systems for ignition fuel supply and denitrification reducing agent supply.

[0021] (5) This invention achieves flexible adjustment of the ratio of hydrogen-ethanol-ether ternary coupled fuel components through the coordinated control of the methanol pipeline electronically controlled splitter and the methanol reforming product pipeline electronically controlled splitter: at low loads, the dimethyl ether production is increased to improve ignition stability; at high loads, the hydrogen production is increased to improve combustion rate and lean-burn limit; and simultaneously, the reducing agent supply ratio is increased to match the increased nitrogen oxide production. Through dynamic adjustment of the ternary fuel component distribution ratio, the optimal fuel supply strategy for different engine loads is realized, overcoming the technical defects of fixed fuel component ratio and poor adaptability of existing reforming systems, and significantly widening the stable operating range of methanol compression ignition engines. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0023] Figure 1 Schematic diagram of a methanol compression ignition engine system using hydrogen alcohol ether ternary coupled fuel; Explanation of the numbers in the diagram: I. Methanol compression ignition engine; II. Methanol evaporator; III. Methanol reforming reactor; 1. Methanol fuel tank; 2-1. Methanol reforming pipeline; 2-2. Methanol premixing pipeline; 2-3. Methanol direct injection pipeline; 2-4. First methanol reforming branch; 2-5. Second methanol reforming branch; 2-6. Premixed fuel pipeline; 3-1. First electronically controlled methanol flow pump; 3-2. Second electronically controlled methanol flow pump; 3-3. Third electronically controlled methanol flow pump; 3-4. Premixed fuel electronically controlled flow pump; 4-1. Evaporator methanol inlet; 4-2. Evaporator exhaust gas inlet; 4-3. Evaporator exhaust gas outlet; 4-4. Evaporator methanol outlet; 5-1. Methanol pipeline electronically controlled distributor; 5-2. Methanol reforming product pipeline. 5-3. Electrically controlled splitter for exhaust gas pipeline; 6-1. Methanol-to-dimethyl ether reforming layer; 6-2. Methanol-to-hydrogen reforming layer; 6-3. Nitrogen oxides catalytic reduction layer; 7-1. Methanol-to-dimethyl ether catalyst; 7-2. Methanol-to-hydrogen catalyst; 7-3. Nitrogen oxides reduction catalyst; 8-1. Outlet pipeline; 8-2. First branch; 8-3. Second branch; 9. Electrically controlled flow valve; 10. Premixed fuel storage tank; 11-1. Methanol direct injection injector; 11-2. Premixed fuel injector; 12. Engine intake manifold; 13. Engine intake valve; 14. Engine exhaust valve; 15-1. First branch of engine exhaust gas; 15-2. Second branch of engine exhaust gas; 16. Exhaust gas outlet of reforming reactor. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] The terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature marked with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified. "Several" means one or more, unless otherwise explicitly specified.

[0026] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments of the present invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0027] Example 1 like Figure 1 As shown, this embodiment provides a methanol compression ignition engine system with hydrogen alcohol ether ternary coupled fuel, including a methanol compression ignition engine I, a methanol evaporator II, a methanol reforming reactor III, a methanol fuel tank 1, and a premixed fuel storage tank 10.

[0028] The methanol evaporator II has two independent passages: one is a methanol passage connecting the evaporator methanol inlet 4-1 and the evaporator methanol outlet 4-4; the other is an engine exhaust gas passage connecting the evaporator exhaust gas inlet 4-2 and the evaporator exhaust gas outlet 4-3. In the methanol passage, the liquid methanol and the high-temperature exhaust gas in the engine exhaust gas passage are independent of each other and only exchange heat. The methanol tank 1 is connected to the methanol inlet 4-1 of the methanol evaporator II. Methanol flows out of the methanol tank 1, passes through the methanol reforming pipeline 2-1, and is quantitatively regulated by the first methanol electronically controlled flow pump 3-1 before being sent into the methanol evaporator II. Then, it leaves the methanol evaporator II through the methanol outlet 4-4. The methanol outlet 4-4 of methanol evaporator II is connected to methanol reforming reactor III via a methanol delivery pipeline. This pipeline is connected in series with an electronically controlled methanol pipeline splitter 5-1, dividing the pipeline into a first methanol reforming branch 2-4 and a second methanol reforming branch 2-5. The first methanol reforming branch 2-4 is connected to the methanol-to-dimethyl ether (DME) reforming layer 6-1 of methanol reforming reactor III, which is filled with a MME catalyst 7-1. The second methanol reforming branch 2-5 is connected to the methanol-to-hydrogen (HH) reforming layer 6-2 of methanol reforming reactor III, which is filled with a HH catalyst 7-2. Engine exhaust gas path: Engine exhaust gas enters the evaporator exhaust gas inlet 4-2 of methanol evaporator II through the first engine exhaust gas branch 15-1. After heat exchange with the liquid methanol in the methanol path, it is sent to the nitrogen oxide catalytic reduction layer 6-3 via the evaporator exhaust gas outlet 4-3.

[0029] The methanol pipeline electronically controlled splitter 5-1 is the core component for flexible adjustment of the hydrogen-ethanol-ether ternary fuel ratio. It can adjust the flow ratio of the two methanol streams in real time according to the operating conditions of the methanol compression ignition engine I, thereby changing the final hydrogen and dimethyl ether component ratios: When the methanol compression ignition engine I operates at low load, the flow ratio of the first methanol reforming branch 2-4 is increased to increase dimethyl ether production, enhance the ignition activity of the premixed mixture, and ensure stable compression ignition. When the methanol compression ignition engine I operates at high load, the flow ratio of the second methanol reforming branch 2-5 is increased to increase hydrogen production, improve combustion rate and lean-burn limit, and allow more unreacted methanol to enter the nitrogen oxide catalytic reduction layer 6-3, matching the increased nitrogen oxide emissions under high load. Through coordinated control with the methanol reforming product pipeline electronically controlled splitter 5-2, the optimal ratio of hydrogen-ethanol-ether ternary fuel components can be achieved for different engine loads, forming a staged fuel supply strategy. In this embodiment, the flow distribution ratio adjustment range of the methanol pipeline electronically controlled splitter 5-1 is 1:1 to 10:1; under rated operating conditions, the flow ratio of the first methanol reforming branch 2-4 to the second methanol reforming branch 2-5 is 8:2.

[0030] The outlet of the methanol-to-dimethyl ether reforming layer 6-1 is connected to an outlet pipe 8-1. A methanol reforming product pipeline electrically controlled splitter 5-2 is connected in series on this pipe, dividing the outlet pipe 8-1 into a first branch 8-2 ​​and a second branch 8-3. The first branch 8-2 ​​is connected to the methanol-to-hydrogen reforming layer 6-2, and the second branch 8-3 is connected to the nitrogen oxide catalytic reduction layer 6-3. In this embodiment, the flow distribution ratio of the methanol reforming product pipeline electrically controlled splitter 5-2 is adjustable within a range of 100:1 to 20:1.

[0031] The methanol reforming reactor III employs a coaxial cylindrical nested structure with walls made of thermally conductive metal. From the inside out, the three chambers are: methanol-to-dimethyl ether reforming layer 6-1, methanol-to-hydrogen reforming layer 6-2, and nitrogen oxide catalytic reduction layer 6-3. The nitrogen oxide catalytic reduction layer 6-3, located on the outermost layer, is in constant contact with the high-temperature exhaust gas and has the highest temperature. Heat is transferred through the walls of the intermediate chambers to the methanol-to-hydrogen reforming layer 6-2, and then to the innermost methanol-to-dimethyl ether reforming layer 6-1, forming a temperature gradient from the outside in. In this embodiment, the temperature of the nitrogen oxide catalytic reduction layer is 350–450°C, the temperature of the methanol-to-hydrogen reforming layer is 250–350°C, and the temperature of the methanol-to-dimethyl ether reforming layer is 200–300°C, forming a stable stepped temperature field that allows for self-sustaining of the reaction heat under rated operating conditions without the need for additional electric heating devices.

[0032] In this embodiment, all catalysts utilize mature commercial systems in the field: methanol-to-dimethyl ether catalyst 7-1 employs a γ-Al₂O₃-based solid acid catalyst; methanol-to-hydrogen catalyst 7-2 employs a Cu / ZnO / Al₂O₃-based copper-based reforming catalyst; and nitrogen oxide reduction catalyst 7-3 employs a molecular sieve-based selective catalytic reduction catalyst. Those skilled in the art can select the corresponding commercial catalyst specifications based on actual operating parameters, achieving this without creative effort.

[0033] After leaving methanol evaporator II, methanol splits into two streams: one stream enters methanol-to-dimethyl ether (DME) reforming layer 6-1 via the first methanol reforming branch 2-4, where it undergoes a dehydration reaction upon contact with DME catalyst 7-1, converting some methanol into dimethyl ether and water vapor. The chemical reaction equation is: 2CH3OH => CH3OCH3 + H2O. The other stream enters methanol-to-hydrogen (HH) reforming layer 6-2 directly via the second methanol reforming branch 2-5. The mixture of methanol, dimethyl ether, and water vapor generated in DME reforming layer 6-1 is fed into HH reforming layer 6-2 via the first branch 8-2, where it mixes with the methanol vapor entering via the second methanol reforming branch 2-5. Under the action of HH catalyst 7-2, a water vapor reforming reaction occurs, producing hydrogen, carbon dioxide, and a small amount of carbon monoxide. The chemical reaction equation is: CH3OH + H2O => 3H2 + CO2, and the side reaction H2 + CO2 <=> H2O + CO (with extremely low CO yield).

[0034] The methanol-to-hydrogen reforming unit 6-2 is connected to the premixed fuel storage tank 10 via a premixed fuel pipeline 2-6. The mixed fuel produced by the methanol-to-hydrogen reforming unit 6-2 is metered into the premixed fuel storage tank 10 under the regulation of the electronically controlled flow valve 9, forming a hydrogen-ethanol-ether ternary coupled fuel together with unreacted methanol. The methanol tank 1 is connected to the premixed fuel storage tank 10 via a methanol premixing pipeline 2-2. A second methanol electronically controlled flow pump 3-2 is connected in series on the methanol premixing pipeline 2-2, and methanol is metered and regulated before being sent into the premixed fuel storage tank 10.

[0035] A delivery pipeline is provided between the premixed fuel storage tank 10 and the premixed fuel injector 11-2, and a premixed fuel electronically controlled flow pump 3-4 is connected in series on the pipeline; the mixed fuel in the premixed fuel storage tank 10 can be injected into the engine intake manifold 12 of the methanol compression ignition engine I through the premixed fuel injector 11-2. The methanol fuel tank 1 is connected to the methanol direct injection injector 11-1 through the methanol direct injection pipeline 2-3, and methanol can be directly injected into the cylinder of the methanol compression ignition engine I through the methanol direct injection injector 11-1.

[0036] The outer layer of methanol reforming reactor III is a nitrogen oxide catalytic reduction layer 6-3, and the interior is filled with nitrogen oxide reduction catalyst 7-3. The methanol and dimethyl ether mixture generated in the methanol-to-dimethyl ether reforming layer 6-1 is fed into the nitrogen oxide catalytic reduction layer 6-3 through the second branch 8-3.

[0037] The engine exhaust valve 14 opens during the exhaust stroke. An electronically controlled exhaust manifold 5-3 is connected in series on the exhaust pipe, dividing it into a first exhaust branch 15-1 and a second exhaust branch 15-2. The first exhaust branch 15-1 is connected to the evaporator exhaust inlet 4-2 of methanol evaporator II, while the second exhaust branch 15-2 is connected to the nitrogen oxide catalytic reduction layer 6-3 of methanol reforming reactor III. Engine exhaust gas enters the evaporator exhaust inlet 4-2 of methanol evaporator II through the first exhaust branch 15-1, exchanges heat with the liquid methanol in the methanol passage, and then enters the nitrogen oxide catalytic reduction layer 6-3 through the evaporator exhaust outlet 4-3. Engine exhaust gas is also directly sent to the nitrogen oxide catalytic reduction layer 6-3 through the second exhaust branch 15-2. In the nitrogen oxide catalytic reduction layer 6-3, the methanol and dimethyl ether mixed medium output from the methanol-to-dimethyl ether reforming layer 6-1 undergoes a selective catalytic reduction reaction with the nitrogen oxides in the tail gas, and the nitrogen oxides are reduced to nitrogen gas. The overall chemical reaction equation is: 12NO + 2CH3OH + CH3OCH3 => 6N2 + 4CO2 + 7H2O. The purified tail gas is discharged into the atmosphere through the tail gas outlet 16 of the reforming reactor.

[0038] Example 2 This embodiment provides a control method for a methanol compression ignition engine system using a hydrogen alcohol ether three-way coupled fuel, employing the system described in Embodiment 1, and includes the following steps: Methanol flows out from methanol tank 1, passes through methanol reforming pipeline 2-1, and is quantitatively regulated by the first methanol electronically controlled flow pump 3-1 before being sent to methanol evaporator II through evaporator methanol inlet 4-1. In the heat exchange channel of methanol evaporator II, methanol evaporates from the liquid phase into gaseous methanol vapor, which is then sent to methanol reforming reactor III through evaporator methanol outlet 4-4. Simultaneously, methanol is sent to premixed fuel storage tank 10 through methanol premixing pipeline 2-2, and the methanol ratio in premixed fuel storage tank 10 is regulated by the second methanol electronically controlled flow pump 3-2. Methanol is then supplied to methanol direct injection injector 11-1 through methanol direct injection pipeline 2-3, quantitatively regulated by the third methanol electronically controlled flow pump 3-3, and directly injected into the cylinder of methanol compression ignition engine I.

[0039] A portion of methanol vapor enters the methanol-to-dimethyl ether (MME) reforming layer 6-1, where it contacts the MME catalyst 7-1 and undergoes a dehydration reaction. Part of the methanol vapor is converted into dimethyl ether and water vapor, generating a first mixed product containing dimethyl ether and water vapor. A portion of this first mixed product is fed into the methanol-to-hydrogen (MH) reforming layer 6-2 via the first branch 8-2, where it mixes with another portion of methanol vapor introduced through the second methanol reforming branch 2-5, forming a mixed medium containing methanol, dimethyl ether, and water vapor. This mixed medium contacts the MME catalyst 7-2 and undergoes a water vapor reforming reaction, where methanol and water vapor are converted into hydrogen, carbon dioxide, and a small amount of carbon monoxide, generating a second mixed product containing hydrogen. This second mixed product is sent to the premixed fuel storage tank 10 via the premixed fuel pipeline 2-6, where it combines with unreacted methanol to form a hydrogen-ethanol-ether ternary coupled fuel, which is then supplied to the methanol compression ignition engine I for combustion.

[0040] Another portion of the first mixed product is fed into the nitrogen oxide catalytic reduction layer 6-3 via the second branch 8-3. During the exhaust stroke of the methanol compression ignition engine I, the exhaust gas of the methanol compression ignition engine I is divided into two paths via the exhaust gas pipeline electronic control splitter 5-3: one path enters the evaporator exhaust gas inlet 4-2 of the methanol evaporator II via the first exhaust gas branch 15-1, serving as a heat source to heat the liquid methanol in the methanol passage, and after heat exchange, it is sent into the nitrogen oxide catalytic reduction layer 6-3; the other path is directly sent into the nitrogen oxide catalytic reduction layer 6-3 via the second exhaust gas branch 15-2. The two exhaust gas paths mix with methanol and dimethyl ether in the nitrogen oxide catalytic reduction layer 6-3, and the heat from the exhaust gas is transferred from the outside to the inside through the thermally conductive partition walls of the three-layer chamber, successively providing the heat required for the reaction in the methanol-to-hydrogen reforming layer 6-2 and the methanol-to-dimethyl ether reforming layer 6-1, without the need for additional heating devices, achieving thermal self-sustaining of the reforming system under rated operating conditions. Nitrogen oxides in the exhaust gas undergo selective catalytic reduction with methanol and dimethyl ether under the action of nitrogen oxide reduction catalyst 7-3 to generate nitrogen gas. The purified exhaust gas is discharged into the atmosphere through the exhaust gas outlet 16 of the reforming reactor.

[0041] The hydrogen alcohol ether ternary coupled fuel in the premixed fuel storage tank 10 is pressurized by the premixed fuel electronically controlled flow pump 3-4 and supplied to the premixed fuel injector 11-2, which injects a metered amount into the engine intake manifold 12. When the engine intake valve 13 opens, it enters the cylinder of the methanol compression ignition engine I along with the intake air. During the compression stroke of the methanol compression ignition engine I, the cylinder is filled with a uniformly mixed premixed gas, including methanol, dimethyl ether, hydrogen, water vapor, carbon dioxide, and carbon monoxide. Due to its high cetane number and excellent ignition characteristics, dimethyl ether is compressed and ignited first, and then compresses and ignites the premixed gas containing methanol and hydrogen. At the same time, the methanol direct injection injector 11-1 injects methanol into the cylinder to supplement the fuel supply and ignite it.

[0042] Preferably, based on the real-time operating load of the methanol compression ignition engine I, the distribution ratio of the methanol pipeline electronically controlled distributor 5-1 and the methanol reforming product pipeline electronically controlled distributor 5-2 is adjusted: at low loads, the proportion of methanol flow entering the methanol-to-dimethyl ether reforming layer 6-1 is increased to increase dimethyl ether production and enhance compression ignition stability; at high loads, the proportion of methanol flow entering the methanol-to-hydrogen reforming layer 6-2 is increased to increase hydrogen production, improve combustion rate and lean-burn limit, and increase the proportion of the first mixed product fed into the nitrogen oxide catalytic reduction layer 6-3 to match nitrogen oxide production and improve denitrification efficiency. Through dynamic adjustment of the distribution ratio of the hydrogen-ethanol-ether ternary coupled fuel group, the optimal fuel supply strategy for different methanol compression ignition engine I loads is achieved.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A methanol compression ignition engine system using hydrogen alcohol ether ternary coupled fuel, characterized in that, The system includes a methanol fuel tank (1), which is connected to a methanol reforming pipeline (2-1), a methanol premixing pipeline (2-2), and a methanol direct injection pipeline (2-3). The methanol reforming pipeline (2-1) is connected to the methanol inlet (4-1) of the methanol evaporator (II). The methanol premixing pipeline (2-2) is connected to the premixed fuel storage tank (10). The methanol direct injection pipeline (2-3) is connected to the methanol direct injection injector (11-1), which is installed on the methanol compression ignition engine (I). The methanol compression ignition engine (I) is connected to an exhaust pipe, which is divided into a first exhaust gas branch (15-1) and a second exhaust gas branch (15-2) by an electronically controlled exhaust gas splitter (5-3). The first exhaust gas branch (15-1) is connected to the exhaust gas inlet (4-2) of the methanol evaporator (II), and the second exhaust gas branch (15-2) is connected to the nitrogen oxide catalytic reduction layer (6-3) of the methanol reforming reactor (III). The methanol evaporator (II) has two independent passages: one is a methanol passage, which connects the methanol inlet (4-1) and the methanol outlet (4-4) of the evaporator; the other is an engine exhaust passage, which connects the exhaust inlet (4-2) and the exhaust outlet (4-3) of the evaporator; the exhaust outlet (4-3) of the evaporator is connected to the nitrogen oxide catalytic reduction layer (6-3). The methanol reforming reactor (III) has a radially coaxial nested three-chamber structure, consisting of a methanol-to-dimethyl ether reforming layer (6-1), a methanol-to-hydrogen reforming layer (6-2), and a nitrogen oxide catalytic reduction layer (6-3) from the inside out. The high-temperature tail gas in the nitrogen oxide catalytic reduction layer (6-3) transfers heat inward through the partition wall, providing a heat source for the reforming reactions of the methanol-to-dimethyl ether reforming layer (6-1) and the methanol-to-hydrogen reforming layer (6-2). The purified tail gas from the nitrogen oxide catalytic reduction layer (6-3) is discharged into the atmosphere through the reforming reactor tail gas outlet (16). The methanol outlet (4-4) of the evaporator is connected to the inlet of the methanol-to-dimethyl ether reforming layer (6-1) and the methanol-to-hydrogen reforming layer (6-2), respectively. The outlet of the methanol-to-dimethyl ether reforming layer (6-1) is connected to the methanol-to-hydrogen reforming layer (6-2). The dimethyl ether mixture generated by the methanol-to-dimethyl ether reforming layer (6-1) enters the methanol-to-hydrogen reforming layer (6-2). The mixture containing dimethyl ether and hydrogen generated by the methanol-to-hydrogen reforming layer (6-2) is sent to the premixed fuel storage tank (10). The mixture containing dimethyl ether and hydrogen and unreacted methanol together form a hydrogen alcohol ether ternary coupled fuel. The premixed fuel storage tank (10) is connected to the engine intake manifold (12) for combustion in the methanol compression ignition engine (I). During the compression stroke, dimethyl ether spontaneously combusts first and then compresses and ignites the premixed mixture containing methanol and hydrogen.

2. The methanol compression ignition engine system with hydrogen alcohol ether ternary coupled fuel according to claim 1, characterized in that, The methanol outlet (4-4) of the evaporator is divided into a first methanol reforming branch (2-4) and a second methanol reforming branch (2-5) via an electrically controlled methanol pipeline splitter (5-1). The first methanol reforming branch (2-4) is connected to the methanol-to-dimethyl ether reforming layer (6-1), and the second methanol reforming branch (2-5) is connected to the methanol-to-hydrogen reforming layer (6-2). The methanol pipeline electronically controlled splitter (5-1) is used to distribute the methanol flow ratio into the methanol-to-dimethyl ether reforming layer (6-1) and the methanol-to-hydrogen reforming layer (6-2) to match the compression ignition requirements and the requirements for improving combustion efficiency of hydrogen production under different operating conditions. The flow distribution ratio adjustment range is 1:1 to 10:

1.

3. The methanol compression ignition engine system with hydrogen alcohol ether ternary coupled fuel according to claim 1, characterized in that, The outlet pipeline (8-1) of the methanol-to-dimethyl ether reforming layer (6-1) is divided into a first branch (8-2) and a second branch (8-3) by an electrically controlled splitter (5-2) for the methanol reforming product pipeline. The first branch (8-2) is connected to the methanol-to-hydrogen reforming layer (6-2), and the second branch (8-3) is connected to the nitrogen oxide catalytic reduction layer (6-3). The dimethyl ether and water vapor generated in the methanol-to-dimethyl ether reforming layer (6-1) are partly fed into the methanol-to-hydrogen reforming layer (6-2) as raw materials for hydrogen production, and the other part is fed into the nitrogen oxide catalytic reduction layer (6-3) as a nitrogen oxide reducing agent, so as to realize the functional reuse of the reforming products. The electrically controlled splitter (5-2) of the methanol reforming product pipeline is used to adjust the flow distribution ratio between the first branch (8-2) and the second branch (8-3), with an adjustment range of 100:1 to 20:

1.

4. The methanol compression ignition engine system with hydrogen alcohol ether ternary coupled fuel according to claim 1, characterized in that, The methanol-to-dimethyl ether reforming layer (6-1) is filled with a methanol-to-dimethyl ether catalyst (7-1), the methanol-to-hydrogen reforming layer (6-2) is filled with a methanol-to-hydrogen catalyst (7-2), and the nitrogen oxide catalytic reduction layer (6-3) is filled with a nitrogen oxide reduction catalyst (7-3).

5. The methanol compression ignition engine system with hydrogen alcohol ether ternary coupled fuel according to claim 1, characterized in that, A first methanol electronically controlled flow pump (3-1) is connected in series on the methanol reforming pipeline (2-1), a second methanol electronically controlled flow pump (3-2) is connected in series on the methanol premixing pipeline (2-2), and a third methanol electronically controlled flow pump (3-3) is connected in series on the methanol direct injection pipeline (2-3).

6. The methanol compression ignition engine system with hydrogen alcohol ether ternary coupled fuel according to claim 1, characterized in that, The outlet of the methanol-to-hydrogen reforming layer (6-2) is connected to the premixed fuel storage tank (10) via the premixed fuel pipeline (2-6). The outlet of the premixed fuel storage tank (10) is connected to the engine intake manifold (12) via the premixed fuel electronically controlled flow pump (3-4) and the premixed fuel injector (11-2). The engine intake manifold (12) is connected to the outside atmosphere and the engine intake valve (13).

7. A control method for a methanol compression ignition engine system using a hydrogen alcohol ether ternary coupled fuel as described in any one of claims 1-6, characterized in that, Includes the following steps: Methanol flows out from the methanol tank (1), passes through the methanol reforming pipeline (2-1) and is sent to the methanol evaporator (II) through the methanol inlet (4-1); in the heat exchange channel of the methanol evaporator (II), the methanol evaporates from the liquid phase to the gas phase methanol vapor, and is then sent to the methanol reforming reactor (III) through the methanol outlet (4-4). A portion of the methanol vapor enters the methanol-to-dimethyl ether reforming layer (6-1), where it undergoes a catalytic dehydration reaction to generate a first mixed product containing dimethyl ether and water vapor. A portion of the first mixed product is fed into the methanol-to-hydrogen reforming layer (6-2), where it is reformed with another portion of methanol vapor to generate a second mixed product containing hydrogen. The second mixed product is fed into the premixed fuel storage tank (10), where it is combined with unreacted methanol to form a hydrogen alcohol ether ternary coupled fuel for combustion in the methanol compression ignition engine (I). Another portion of the first mixed product is fed into the nitrogen oxide catalytic reduction layer (6-3). The exhaust gas of the methanol compression ignition engine (I) is divided into two paths. One path is sent to the nitrogen oxide catalytic reduction layer (6-3) after heat exchange in the methanol evaporator (II), and the other path is sent directly to the nitrogen oxide catalytic reduction layer (6-3). The heat of the exhaust gas is transferred from the outside to the inside through the thermally conductive partition wall of the three-layer chamber, providing a heat source for the reforming reaction of the methanol to dimethyl ether reforming layer (6-1) and the methanol to hydrogen reforming layer (6-2).

8. The control method for a methanol compression ignition engine system using a hydrogen alcohol ether ternary coupled fuel according to claim 7, characterized in that, Before the methanol is evaporated into gaseous methanol vapor by the methanol evaporator (II), the process further includes: Methanol is fed into the premixed fuel storage tank (10) via the methanol premixing pipeline (2-2) to adjust the methanol ratio in the premixed fuel storage tank (10); Methanol is supplied to the methanol direct injection injector (11-1) via the methanol direct injection pipeline (2-3) and directly injected into the cylinder of the methanol compression ignition engine (I).

9. The control method for a methanol compression ignition engine system using a hydrogen alcohol ether ternary coupled fuel according to claim 7, characterized in that, The hydrogen alcohol ether ternary coupled fuel in the premixed fuel storage tank (10) is injected into the engine intake manifold (12) through the premixed fuel injector (11-2). During the compression stroke, the dimethyl ether is the first to spontaneously combust and compressively ignites the premixed mixture containing methanol and hydrogen.

10. The control method for a methanol compression ignition engine system using a hydrogen alcohol ether ternary coupled fuel according to claim 7, characterized in that, Based on the real-time operating load of the methanol compression ignition engine (I), under low load, the proportion of methanol flow entering the methanol-to-dimethyl ether reforming layer (6-1) is increased to increase the amount of dimethyl ether produced. Under high load, the proportion of methanol flow entering the methanol-to-hydrogen reforming layer (6-2) is increased to increase the amount of hydrogen produced and the proportion of the first mixed product fed into the nitrogen oxide catalytic reduction layer (6-3) is increased.

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