Methanol diesel engine and its starting method

Abstract

This invention relates to the field of engine technology and discloses a methanol-diesel engine and its starting method. The engine includes a working cylinder, a reforming cylinder, and a reforming gas recirculation pipeline. The working cylinder is equipped with a diesel fuel injector, and the intake manifold of the working cylinder is equipped with a first methanol fuel injector. The reforming cylinder is equipped with a second methanol fuel injector and a reforming cylinder spark plug. The reforming cylinder is connected to the engine intake port through the reforming gas recirculation pipeline. The diesel fuel injector injects diesel fuel into the working cylinder, forming a methanol-rich premixed gas in the reforming cylinder. After ignition by the reforming cylinder spark plug, the methanol-rich premixed gas is oxidized and reformed to generate reformed gas rich in active substances. This reformed gas then flows back through the reforming gas recirculation pipeline to mix with fresh air before finally flowing into the methanol-diesel engine through the engine intake port. The reformed gas is introduced into the working cylinder to participate in combustion, thereby improving cold start efficiency.

Description

Technical Field

[0001] This invention relates to the field of engine technology, and in particular to a methanol diesel engine and its starting method. Background Technology

[0002] Methanol-fueled engines have advantages in terms of economy, power, and pollutant emissions, making them a viable alternative to traditional petroleum fuels.

[0003] For intake-port methanol injection engines, the difficulty of cold start at low temperatures is one of the problems they face. The main reason is that the concentration of the methanol-air mixture is insufficient or the temperature of the mixture is too low, which makes ignition difficult.

[0004] Therefore, how to improve the cold start efficiency of methanol fuel engines is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] The objective of this invention is to at least solve the technical problem of how to improve the cold start efficiency of methanol fuel engines. This objective is achieved through the following technical solution:

[0006] In a first aspect, the present invention provides a methanol-diesel engine, comprising: an engine intake port; an engine exhaust port; at least one working cylinder, wherein a diesel fuel injector is provided on the cylinder head of the working cylinder, the working cylinder is connected to the engine intake port through a working cylinder intake manifold, a first methanol fuel injector is provided on the working cylinder intake manifold, and the working cylinder is connected to the engine exhaust port through a working cylinder exhaust manifold; at least one reforming cylinder, wherein a second methanol fuel injector and a reforming cylinder spark plug are provided on the cylinder head of the reforming cylinder, the reforming cylinder is connected to the engine intake port through a reforming cylinder intake manifold, and the reforming cylinder intake manifold is arranged in parallel with the working cylinder intake manifold; and a reforming gas recirculation pipeline, wherein the reforming cylinder is connected to the engine intake port through the reforming gas recirculation pipeline.

[0007] In this methanol-diesel engine, the first methanol fuel injector injects methanol fuel into the intake manifold of the working cylinder. The methanol fuel mixes with fresh air and flows into the working cylinder. Simultaneously, the diesel fuel injector injects diesel fuel into the working cylinder to ignite the gas mixture. The second methanol fuel injector also injects methanol fuel to create a methanol-rich premixed gas in the reforming cylinder. This premixed gas is then ignited by the spark plug in the reforming cylinder, undergoing oxidative reforming to form a reformed gas rich in active substances. This reformed gas primarily consists of a mixture of small hydrocarbon molecules such as CO (carbon monoxide), HC (hydrocarbons), and H2 (hydrogen). The reformed gas is then returned to the engine intake through a reformed gas recirculation pipeline to mix with fresh air before flowing back into the methanol-diesel engine. This ensures that the reformed gas rich in active substances is introduced into the working cylinder for combustion. This cycle repeats until combustion is complete. Therefore, this methanol diesel engine, through the setting of reforming cylinder and reforming gas circulation pipeline, enables the combustion of reforming gas rich in active substances in the working cylinder, thereby improving the cold start efficiency of the methanol diesel engine.

[0008] In some embodiments of the present invention, a reforming gas cooler is provided on the reforming gas circulation pipeline.

[0009] In some embodiments of the present invention, the methanol diesel engine further includes a gas mixer, wherein the engine intake port and the end of the reforming gas circulation pipeline away from the reforming cylinder are respectively connected to the intake end of the gas mixer, and the intake manifold of the working cylinder and the intake manifold of the reforming cylinder are respectively connected to the exhaust end of the gas mixer.

[0010] In some embodiments of the present invention, the methanol diesel engine includes a reforming cylinder and three working cylinders, with the reforming cylinder and the three working cylinders arranged sequentially in a straight line.

[0011] In some embodiments of the present invention, the methanol diesel engine includes three working cylinder intake manifolds, the three working cylinder intake manifolds are arranged in a one-to-one correspondence with the three working cylinders, the three working cylinder intake manifolds are connected in parallel, and each working cylinder intake manifold is provided with a first methanol fuel injector.

[0012] In some embodiments of the present invention, the methanol diesel engine includes three working cylinder exhaust manifolds, the three working cylinder exhaust manifolds are arranged in a one-to-one correspondence with the three working cylinders, and the three working cylinder exhaust manifolds are connected in parallel.

[0013] In some embodiments of the present invention, the cylinder head of the working cylinder is provided with a spiral air intake passage, and the intake manifold of the working cylinder is connected to the working cylinder through the spiral air intake passage.

[0014] In some embodiments of the present invention, the methanol-diesel engine further includes an electronic control unit, which is signal-connected to the first methanol fuel injector, the diesel fuel injector, the second methanol fuel injector, and the reforming cylinder spark plug.

[0015] Secondly, the present invention provides a methanol diesel engine starting method applicable to any of the aforementioned methanol diesel engines, characterized by comprising a first working cycle and a second working cycle; the first working cycle comprising: controlling a first methanol fuel injector to inject methanol fuel and allowing fresh air to enter the methanol diesel engine from the engine intake port, so that the methanol fuel mixes with the fresh air and flows into the working cylinder; controlling a diesel fuel injector to inject diesel fuel into the working cylinder to ignite the gas mixture in the working cylinder; and controlling a second methanol fuel injector to inject methanol fuel to form a combustion mixture in the reforming cylinder. Methanol-rich premixed gas; controlling the spark plug ignition in the reforming cylinder to oxidize and reform the methanol-rich premixed gas to form reformed gas rich in active substances in the reforming cylinder, allowing the reformed gas to flow back to the engine intake through the reformed gas circulation pipeline to mix with fresh air, at which point the first working cycle ends; the second working cycle includes: controlling the first methanol fuel injector to inject methanol fuel so that the mixture of reformed gas and fresh air flows into the working cylinder; controlling the diesel fuel injector to inject diesel fuel in the working cylinder to ignite the gas mixture in the working cylinder; continuously repeating the second working cycle until combustion ends.

[0016] In some embodiments of the present invention, controlling the diesel fuel injector to inject diesel fuel into the working cylinder to cause the gas mixture in the working cylinder to burn specifically includes: pre-injecting diesel fuel into the working cylinder to cause the diesel fuel to undergo low-temperature partial oxidation and reforming in the working cylinder to produce active substances; and main-injecting diesel fuel into the working cylinder to cause the diesel fuel to ignite the gas mixture in the working cylinder to burn; wherein, the injection pulse width of the diesel fuel during the main injection process is greater than the injection pulse width of the diesel fuel during the pre-injection process.

[0017] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0018] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0019] Figure 1This is a schematic diagram of the structure of a methanol diesel engine provided in an embodiment of the present invention;

[0020] Figure 2 This is a partial structural diagram of the working cylinder in a methanol diesel engine provided in an embodiment of the present invention;

[0021] Figure 3 This is a schematic diagram of the injection timing of pre-injected diesel and main-injected diesel in the methanol diesel engine starting method provided in the embodiments of the present invention;

[0022] Figure 4 This is a schematic diagram of the internal region distribution of the working cylinder in a methanol diesel engine provided in an embodiment of the present invention.

[0023] The attached figures are labeled as follows:

[0024] 10. Methanol diesel engine;

[0025] 100. Engine air intake; 110. Gas mixer;

[0026] 200. Engine exhaust port;

[0027] 300. Working cylinder; 310. Spiral intake manifold; 301. First zone; 302. Second zone; 303. Third zone;

[0028] 400. Diesel fuel injector;

[0029] 510. Working cylinder intake manifold; 511. First methanol fuel injector; 520. Working cylinder exhaust manifold;

[0030] 600, Reformer cylinder; 610, Reformer cylinder spark plug; 620, Second methanol fuel injector;

[0031] 710. Reformer intake manifold; 720. Reformer gas circulation pipeline; 721. Reformer gas cooler. Detailed Implementation

[0032] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0033] It should be understood that the terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “described” as used herein may also include the plural forms. The terms “comprising,” “including,” “containing,” and “having” are inclusive and therefore indicate the presence of the stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein are not construed as requiring them to be performed in a particular order described or illustrated unless the order of performance is explicitly indicated. It should also be understood that additional or alternative steps may be used.

[0034] Although terms such as first, second, third, etc., may be used in this document to describe multiple elements, components, regions, layers, and / or segments, these elements, components, regions, layers, and / or segments should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer, or segment from another. Unless the context clearly indicates otherwise, terms such as "first," "second," and other numerical terms used herein do not imply order or sequence. Therefore, the first element, component, region, layer, or segment discussed below may be referred to as the second element, component, region, layer, or segment without departing from the teachings of the exemplary embodiments.

[0035] For ease of description, spatial relative terms may be used in the text to describe the relationship of one element or feature relative to another element or feature, as shown in the figure. These relative terms include, for example, "inside," "outside," "middle," "outer," "below," "below," "above," "over," etc. Such spatial relative terms are intended to include different orientations of the device in use or operation, other than those depicted in the figure. For example, if the device in the figure is flipped, an element described as "below other elements or features" or "below other elements or features" would subsequently be oriented as "above other elements or features" or "above other elements or features." Therefore, the example term "below" can include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or in other directions), and the spatial relative descriptors used in the text will be interpreted accordingly.

[0036] Figure 1 This is a schematic diagram of the structure of a methanol diesel engine provided in an embodiment of the present invention, as shown below. Figure 1As shown, an embodiment of the present invention provides a methanol diesel engine 10, comprising: an engine intake port 100; an engine exhaust port 200; at least one working cylinder 300, wherein a diesel fuel injector 400 is provided on the cylinder head of the working cylinder 300, the working cylinder 300 is connected to the engine intake port 100 through a working cylinder intake manifold 510, a first methanol fuel injector 511 is provided on the working cylinder intake manifold 510, and the working cylinder 300 is connected to the engine exhaust port 100 through a working cylinder exhaust manifold 520. The engine exhaust port 200 is connected; at least one reforming cylinder 600, the cylinder head of the reforming cylinder 600 is equipped with a second methanol fuel injector 620 and a reforming cylinder spark plug 610, the reforming cylinder 600 is connected to the engine intake port 100 through the reforming cylinder intake manifold 710, the reforming cylinder intake manifold 710 is set in parallel with the working cylinder intake manifold 510; and a reforming gas circulation pipeline 720, the reforming cylinder 600 is connected to the engine intake port 100 through the reforming gas circulation pipeline 720.

[0037] In this embodiment, when the methanol-diesel engine 10 is operating, the first methanol fuel injector 511 injects methanol fuel into the intake manifold 510 of the working cylinder. The methanol fuel mixes with fresh air and flows into the working cylinder 300. Meanwhile, the diesel fuel injector 400 injects diesel fuel into the working cylinder 300 to ignite the gas mixture within it. The second methanol fuel injector 620 also injects methanol fuel to form a methanol-rich premixed gas in the reforming cylinder 600. It then controls the spark plug 610 in the reforming cylinder to ignite the methanol-rich premixed gas, oxidizing and reforming it to form a reformed gas rich in active substances within the reforming cylinder 600. The reformed gas mainly includes a mixture of small hydrocarbon molecules such as CO (carbon monoxide), HC (hydrocarbons), and H2 (hydrogen). The reformed gas flows back to the engine intake port 100 through the reformed gas circulation pipeline 720 to mix with fresh air, and then flows into the methanol diesel engine 10 through the engine intake port 100, so that the reformed gas rich in active substances can be introduced into the working cylinder 300 to participate in combustion. This cycle repeats until combustion is completed.

[0038] Therefore, this methanol diesel engine 10, through the setting of reforming cylinder 600 and reforming gas circulation pipeline 720, enables the working cylinder 300 to have reforming gas rich in active substances participating in combustion, thereby improving the cold start efficiency of methanol diesel engine 10.

[0039] As is easily understood, the combustion exhaust gas generated in the working cylinder 300 will flow through the working cylinder exhaust manifold 520 and finally be discharged from the engine exhaust port 200. Valves can be installed at the connection points between the engine intake port 100, the engine exhaust port 200, the reforming gas circulation pipeline 720 and the reforming cylinder 600 to control the gas flow path according to the actual situation.

[0040] refer to Figure 1 According to an optional embodiment of the present invention, a reforming gas cooler 721 is provided on the reforming gas circulation pipeline 720.

[0041] In this embodiment, since the reformed gas flowing into the reformed gas circulation pipeline 720 will eventually mix with fresh air and then flow back into the methanol diesel engine 10 through the engine intake port 100, the presence of a reformed gas cooler 721 on the reformed gas circulation pipeline 720 ensures that the temperature of the reformed gas is not too high, thereby ensuring the intake volume of the methanol diesel engine 10. In addition, since nitrogen and oxygen only undergo chemical reaction under high temperature conditions, the reformed gas cooler 721 can also reduce the generation of nitrogen oxides, improve the environmental friendliness of the exhaust of the methanol diesel engine 10, and reduce environmental pollution to a certain extent.

[0042] Among them, the reformed gas cooler 721 can be an exhaust gas recirculation (EGR) cooler.

[0043] Continue to refer to Figure 1 According to an optional embodiment of the present invention, the methanol diesel engine 10 further includes a gas mixer 110, wherein the engine intake port 100 and the end of the reforming gas circulation pipeline 720 opposite to the reforming cylinder 600 are connected to the intake end of the gas mixer 110, and the working cylinder intake manifold 510 and the reforming cylinder intake manifold 710 are respectively connected to the exhaust end of the gas mixer 110.

[0044] In this embodiment, it is easy to understand that the function of the gas mixer 110 is to ensure that the gas flowing into the methanol diesel engine 10 (e.g., a mixture of reformed gas and fresh air) is fully mixed, thereby making the gas composition in the working cylinder intake manifold 510 and the reformed cylinder intake manifold 710 uniform, and improving the working efficiency of the methanol diesel engine 10.

[0045] like Figure 1 As shown, according to an optional embodiment of the present invention, the methanol-diesel engine 10 includes a reforming cylinder 600 and three working cylinders 300, which are arranged sequentially in a straight line. The methanol-diesel engine 10 includes three intake manifolds 510 for each working cylinder, which are arranged one-to-one with each of the three working cylinders 300. The three intake manifolds 510 are connected in parallel, and each working cylinder intake manifold 510 is equipped with a first methanol fuel injector 511. The methanol-diesel engine 10 includes three exhaust manifolds 520 for each working cylinder, which are arranged one-to-one with each of the three working cylinders 300. The three exhaust manifolds 520 are connected in parallel.

[0046] In this embodiment, the methanol diesel engine 10 is a four-cylinder inline engine as an example for illustration:

[0047] When this methanol-diesel engine 10 is operating, three first methanol fuel injectors 511 inject methanol fuel into the intake manifolds 510 of the three working cylinders, respectively. The methanol fuel mixes with fresh air and flows into the three working cylinders 300 through the intake manifolds 510. Simultaneously, three diesel fuel injectors 400 inject diesel fuel into the three working cylinders 300 to ignite the gas mixture within them. A second methanol fuel injector 620 also injects methanol fuel to form a methanol-rich premixed gas in the reforming cylinder 600. This injector controls the spark plug 610 in the reforming cylinder to ignite the methanol-rich premixed gas, oxidizing and reforming it to form a reformed gas rich in active substances within the reforming cylinder 600. The reformed gas mainly includes a mixture of small hydrocarbon molecules such as CO (carbon monoxide), HC (hydrocarbons), and H2 (hydrogen). The reformed gas flows back to the engine intake port 100 through the reformed gas circulation pipeline 720 to mix with fresh air, and then flows into the methanol diesel engine 10 through the engine intake port 100, so that the reformed gas rich in active substances can be introduced into the three working cylinders 300 to participate in combustion. This cycle repeats until combustion is completed.

[0048] It is easy to understand that the above-mentioned methanol diesel engine 10 is a four-cylinder inline engine scheme only for illustrative purposes. Under actual working conditions, the specific type of cylinder arrangement of the methanol diesel engine 10 and the number of working cylinders 300 and reforming cylinders 600 should be based on the actual working conditions and are not subject to specific restrictions.

[0049] The following provides a more detailed example illustrating the specific structure and dimensions of this methanol-diesel engine 10:

[0050] The methanol-diesel engine 10 has a compression ratio range of 14:1-16:1, a stroke of 300mm, and both the working cylinder 300 and the reforming cylinder 600 can have a bore of 210mm. The connecting rod length is 550mm, and the crankshaft crank radius is 150mm. The working cylinder intake manifold 510 and the reforming cylinder intake manifold are both 480mm long and 100mm in diameter. The working cylinder exhaust manifold 520 can be set to a length range of 300mm-500mm, and its diameter can be 150mm. The reforming gas recirculation pipeline 720 is set to a length of 500mm and a diameter of 150mm. Water-cooling pipelines can also be installed on the cylinder head of the working cylinder 600.

[0051] Similarly, the structure and dimensions of the methanol diesel engine 10 described above are for illustrative purposes only. In actual operating conditions, the specific requirements of the operating conditions shall prevail, and no restrictions shall be imposed.

[0052] Figure 2 This is a partial structural diagram of the working cylinder in a methanol diesel engine provided in an embodiment of the present invention, and is also referred to herein. Figure 1 and Figure 2 According to an optional embodiment of the present invention, the cylinder head of the working cylinder 300 is provided with a spiral intake passage 310, and the working cylinder intake manifold 510 is connected to the working cylinder 300 through the spiral intake passage 310.

[0053] In this embodiment, it is easy to understand that the spiral intake manifold 310 enables the gas flowing into the working cylinder 300 from the working cylinder intake manifold 510 to be mixed more thoroughly, improving the distribution of the mixture in the working cylinder 300, thereby ultimately enabling more complete combustion; in addition, the spiral intake manifold 310 can also reduce airflow resistance to improve the intake efficiency of the methanol diesel engine 10.

[0054] According to an optional embodiment of the present invention, the methanol diesel engine 10 further includes an electronic control unit (not shown in the figure), which is signal-connected to the first methanol fuel injector 511, the diesel fuel injector 400, the second methanol fuel injector 620, and the reformer cylinder spark plug 610.

[0055] In this embodiment, the Electronic Control Unit (ECU) can store the injection strategies of the first methanol fuel injector 511, the diesel fuel injector 400, and the second methanol fuel injector 620, as well as the timing of the reformer spark plug 610, so as to issue commands at appropriate times to control fuel injection and ignition.

[0056] This invention also provides a methanol-diesel engine starting method applicable to any of the methanol-diesel engines 10 described above, characterized by comprising a first working cycle and a second working cycle; the first working cycle comprising: controlling a first methanol fuel injector 511 to inject methanol fuel and allowing fresh air to enter the methanol-diesel engine 10 through the engine intake port 100, so that the methanol fuel mixes with the fresh air and flows into the working cylinder 300; controlling a diesel fuel injector 400 to inject diesel fuel into the working cylinder 300 to cause the gas mixture in the working cylinder 300 to burn; and controlling a second methanol fuel injector 620 to inject methanol fuel to form a combustion mixture in the reforming cylinder 600. Methanol-rich premixed gas; ignition of spark plug 610 in reforming cylinder to oxidize and reform the methanol-rich premixed gas to form reformed gas rich in active substances in reforming cylinder 600, allowing the reformed gas to flow back to engine intake port 100 through reformed gas circulation pipe 720 to mix with fresh air, at which point the first working cycle ends; the second working cycle includes: controlling the first methanol fuel injector 511 to inject methanol fuel so that the mixture of reformed gas and fresh air flows into working cylinder 300; controlling the diesel fuel injector 400 to inject diesel fuel in working cylinder 300 to ignite the gas mixture in working cylinder 300; continuously repeating the second working cycle until combustion ends.

[0057] In this embodiment, the methanol diesel engine starting method, during the first cycle:

[0058] First, control the first methanol fuel injector 511 to inject methanol fuel and allow fresh air to enter the methanol diesel engine 10 through the engine intake port 100, so that the methanol fuel and fresh air are mixed and flow into the working cylinder 300.

[0059] Then, the diesel fuel injector 400 is controlled to inject diesel fuel into the working cylinder 300 so that the gas mixture in the working cylinder 300 is combusted;

[0060] Next, the spark plug 610 of the reforming cylinder is ignited to oxidize and reform the methanol-rich premixed gas to form reformed gas rich in active substances in the reforming cylinder 600. The reformed gas is then returned to the engine intake port 100 through the reformed gas circulation pipeline 720 to mix with fresh air. At this point, the first working cycle ends.

[0061] This method of starting a methanol diesel engine during the second cycle:

[0062] First, control the first methanol fuel injector 511 to inject methanol fuel so that the mixture of reformed gas and fresh air flows into the working cylinder 300.

[0063] Then, the diesel fuel injector 400 is controlled to inject diesel fuel into the working cylinder 300 so that the gas mixture in the working cylinder 300 is combusted.

[0064] Finally, repeat the second cycle continuously until combustion ends.

[0065] In this methanol-diesel engine starting method, after the methanol-diesel engine 10 has undergone the first cycle, reformed gas will continuously participate in combustion in the second cycle. As can be seen from the above analysis, the reformed gas is a mixture of hydrocarbon small molecule active substances, mainly including CO (carbon monoxide), HC (hydrocarbons), H2 (hydrogen), etc., which can improve combustion efficiency and thus improve the cold start efficiency of the methanol-diesel engine 10.

[0066] The gas flow path can be referenced. Figure 1 In the diagram, taking the first cycle as an example, the thinner arrows can be seen as the flow path of the mixture that does not include reformed gas, while the thicker arrows are the flow path of the mixture that includes reformed gas.

[0067] In addition, the injection timing of the second methanol fuel injector 620 and the ignition timing of the reformer spark plug 610 should be in the early stage of the compression stroke.

[0068] Furthermore, a gas mixer 110 can be installed at the engine intake port 100 to ensure that the gas flowing into the methanol diesel engine 10 from the engine intake port 100 (such as the mixture of reformed gas and fresh air in the second cycle) can be fully mixed, thereby making the gas composition in the working cylinder intake manifold 510 and the reforming cylinder intake manifold 710 uniform and improving the working efficiency of the methanol diesel engine 10.

[0069] It is easy to understand that an intake valve can be installed at the engine intake port 100, and the intake valve, the first methanol fuel injector 511, the second methanol fuel injector, and the reformer spark plug 610 can all be connected to the electronic control unit. The electronic control unit is used to control the opening and closing of the engine intake port 100, the fuel injection of the first methanol fuel injector 511 and the second methanol fuel injector 620, and the ignition of the reformer spark plug 610.

[0070] Figure 3 This is a schematic diagram illustrating the injection timing of pre-injected diesel and main-injected diesel in the methanol diesel engine starting method provided in this embodiment of the invention, as shown below. Figure 3As shown, specifically, according to an optional embodiment of the present invention, controlling the diesel fuel injector 400 to inject diesel fuel into the working cylinder 300 to cause the gas mixture in the working cylinder 300 to burn specifically includes: performing a pre-injection of diesel fuel in the working cylinder 300, causing the diesel fuel to undergo low-temperature partial oxidation and reforming in the working cylinder 300 to produce active substances; performing a main injection of diesel fuel in the working cylinder 300, causing the diesel fuel to ignite the gas mixture in the working cylinder 300 to burn; wherein, the injection pulse width of the diesel fuel during the main injection process is greater than the injection pulse width of the diesel fuel during the pre-injection process.

[0071] In this embodiment, when the gas (fresh air if the methanol-diesel engine 10 is in the first cycle; a mixture of reformed gas and fresh air if the methanol-diesel engine 10 is in the second cycle) flows into the methanol-diesel engine 10, it will eventually flow into the working cylinder 300 together with the methanol fuel in the intake manifold 510 of the working cylinder. At this time, the diesel fuel injector 400 is controlled to pre-inject diesel fuel in the working cylinder 300. The pre-injected diesel fuel undergoes partial low-temperature oxidation and reforming in the working cylinder 300 to produce active substances. Based on the above analysis of the spiral intake manifold 310, it can be seen that the active substances can be evenly distributed in the working cylinder 300. Then, the diesel fuel injector 400 is controlled to perform the main injection of diesel fuel in the working cylinder 300. After the main injection of diesel fuel enters the working cylinder 300, it undergoes a short ignition delay period before igniting and burning, ultimately igniting the gas mixture in the working cylinder 300, thereby improving the combustion efficiency.

[0072] Based on the above analysis, it is easy to understand that the main purpose of diesel fuel pre-injection is to generate active substances rich in small molecules to improve combustion efficiency, while the purpose of diesel fuel main injection is to perform combustion work inside the working cylinder 300.

[0073] The following example illustrates diesel fuel injection under a specific operating condition: Pre-injection of diesel fuel can occur when the crankshaft angle is 25°CA before top dead center (TDC) to 20°CA before TDC. Main injection of diesel fuel can occur when the crankshaft angle is 10°CA before TDC to 10°CA after TDC. It's important to understand that the above-mentioned timings for main and pre-injection are merely illustrative. In actual operating conditions, the specific timing should be based on actual requirements. The goal is to ensure that the pre-injected diesel fuel generates active substances rich in small molecules to improve combustion efficiency, and that the main-injected diesel fuel meets the basic combustion and power requirements of the 300rpm working cylinder. No specific limitations are imposed.

[0074] Figure 4 This is a schematic diagram of the internal region distribution of the working cylinder in a methanol diesel engine provided in an embodiment of the present invention, and is also referred to. Figure 4To further understand the combustion situation within the working cylinder 300, the working cylinder 300 is divided into three zones: Zone 1 301, Zone 2 302, and Zone 303. Taking the second cycle of the methanol diesel engine 10 as an example, a more detailed explanation of the combustion situation within the working cylinder 300 will be provided:

[0075] First, after diesel fuel is pre-injected into the working cylinder 300, the first zone 301 of the working cylinder 300 includes methanol fuel, air, reforming gas, and active substances produced by low-temperature partial oxidation reforming.

[0076] Then, when the main diesel fuel injection is performed, the main injected diesel fuel enters the working cylinder 300 and the main injected diesel fuel fills the second zone 302 of the working cylinder 300.

[0077] Next, since the reformed gas in the first zone 301 and the main injected diesel fuel in the second zone 302 can enhance the thermochemical atmosphere of the first zone 301, the mixed gas in the first zone 301 can be ignited by the main injected diesel fuel in the second zone 302 in the third zone 303.

[0078] It should be noted that since reformed gas is introduced into the working cylinder 300 to participate in combustion, the combustion temperature can be reduced, thereby reducing the concentration of nitrogen oxides generated in the end, which in turn more effectively improves the environmental protection level of the final methanol diesel engine exhaust and further reduces environmental pollution.

[0079] In summary, this methanol-diesel engine starting method can improve combustion efficiency by circulating reformed gas and using multiple diesel injection technology when the methanol-diesel engine 10 is in a cold start condition.

[0080] In addition, this methanol-diesel engine starting method also has the beneficial effect of improving environmental protection, as detailed below:

[0081] It is easy to understand that when methanol diesel engine 10 burns in working cylinder 300, it easily produces HO2 (hydrogen superoxide), and at high temperature, it also easily produces a large amount of NO (nitric oxide). Therefore, the chemical reaction HO2 + NO = NO2 + OH will occur in working cylinder 300. In other words, a large amount of NO2 (nitric oxide) will eventually be discharged into the atmosphere from engine exhaust port 200, which poses a risk of violating emission regulations and polluting the environment.

[0082] When the main injection diesel fuel in the working cylinder 300 of the methanol diesel engine using this methanol diesel engine starting method is burned, the pre-injected diesel fuel can generate active substances in the working cylinder 300, which can cause the temperature of the combustion zone in the working cylinder 300 to exceed the HO2 oxidation threshold, thereby consuming a large amount of HO2 generated by the oxidation of methanol fuel. In addition, due to the presence of reformed gas, the maximum combustion temperature and oxygen concentration in the working cylinder 300 can be reduced, thereby suppressing NO generated by high-temperature combustion. As mentioned above, HO2 and NO can react chemically to generate NO2. In other words, this methanol diesel engine starting method can effectively reduce the generation of HO2 and NO, thereby effectively reducing NO2 emissions and improving the environmental friendliness of the methanol diesel engine 10, reducing environmental pollution to a certain extent.

[0083] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for starting a methanol diesel engine, characterized in that, The methanol-diesel engine includes: Engine air intake (100); Engine exhaust port (200); At least one working cylinder (300) is provided with a diesel fuel injector (400) on the cylinder head of the working cylinder (300), the working cylinder (300) is connected to the engine intake port (100) through a working cylinder intake manifold (510), a first methanol fuel injector (511) is provided on the working cylinder intake manifold (510), and the working cylinder (300) is connected to the engine exhaust port (200) through a working cylinder exhaust manifold (520); At least one reforming cylinder (600), the cylinder head of which is provided with a second methanol fuel injector (620) and a reforming cylinder spark plug (610), the reforming cylinder (600) being connected to the engine intake port (100) via a reforming cylinder intake manifold (710), the reforming cylinder intake manifold (710) being arranged in parallel with the working cylinder intake manifold (510); and Reformer gas recirculation pipeline (720), through which the reformer cylinder (600) is connected to the engine intake port (100); The methanol-diesel engine starting method includes a first working cycle and a second working cycle; The first work cycle includes: The first methanol fuel injector (511) is controlled to inject methanol fuel and fresh air is allowed to enter the methanol diesel engine (10) through the engine intake port (100) so that the methanol fuel and fresh air are mixed and flow into the working cylinder (300). The diesel fuel injector (400) is controlled to inject diesel fuel into the working cylinder (300) to cause the gas mixture in the working cylinder (300) to burn; The second methanol fuel injector (620) is controlled to inject methanol fuel to form a methanol-rich premixed gas in the reforming cylinder (600); The spark plug (610) of the reforming cylinder is controlled to ignite and the methanol-rich premixed gas is oxidized and reformed to form reformed gas rich in active substances in the reforming cylinder (600). The reformed gas is then returned to the engine intake port (100) through the reformed gas circulation pipeline (720) to mix with fresh air. At this time, the first working cycle ends. The second work cycle includes: The first methanol fuel injector (511) is controlled to inject methanol fuel so that the mixture of reformed gas and fresh air flows into the working cylinder (300). The diesel fuel injector (400) is controlled to inject diesel fuel into the working cylinder (300) to cause the gas mixture in the working cylinder (300) to burn; Repeat the second working cycle continuously until combustion ends.

2. The methanol diesel engine starting method according to claim 1, characterized in that, The reforming gas circulation pipeline (720) is equipped with a reforming gas cooler (721).

3. The methanol diesel engine starting method according to claim 1, characterized in that, The methanol diesel engine (10) also includes a gas mixer (110). The engine intake port (100) and the end of the reforming gas circulation pipeline (720) away from the reforming cylinder (600) are respectively connected to the intake end of the gas mixer (110). The working cylinder intake manifold (510) and the reforming cylinder intake manifold (710) are respectively connected to the exhaust end of the gas mixer (110).

4. The methanol diesel engine starting method according to claim 1, characterized in that, The methanol diesel engine (10) includes one reforming cylinder (600) and three working cylinders (300), with the reforming cylinder (600) and the three working cylinders (300) arranged sequentially in a straight line.

5. The methanol diesel engine starting method according to claim 4, characterized in that, The methanol diesel engine (10) includes three working cylinder intake manifolds (510), which are arranged one-to-one with the three working cylinders (300). The three working cylinder intake manifolds (510) are connected in parallel, and each working cylinder intake manifold (510) is provided with a first methanol fuel injector (511).

6. The methanol diesel engine starting method according to claim 4, characterized in that, The methanol diesel engine (10) includes three working cylinder exhaust manifolds (520), which are arranged one-to-one with the three working cylinders (300), and the three working cylinder exhaust manifolds (520) are connected in parallel.

7. The methanol diesel engine starting method according to claim 1, characterized in that, The cylinder head of the working cylinder (300) is provided with a spiral air intake passage (310), and the working cylinder intake manifold (510) is connected to the working cylinder (300) through the spiral air intake passage (310).

8. The methanol diesel engine starting method according to any one of claims 1-7, characterized in that, The methanol-diesel engine (10) also includes an electronic control unit, which is signal-connected to the first methanol fuel injector (511), the diesel fuel injector (400), the second methanol fuel injector (620), and the reformer spark plug (610).

9. The methanol diesel engine starting method according to claim 1, characterized in that, The control of the diesel fuel injector (400) to inject diesel fuel into the working cylinder (300) to cause combustion of the gas mixture in the working cylinder (300) specifically includes: Diesel fuel is pre-injected into the working cylinder (300) to cause the diesel fuel to undergo low-temperature partial oxidation and reforming in the working cylinder (300) to produce active substances; Diesel fuel is injected into the working cylinder (300) to ignite the gas mixture in the working cylinder (300); In the case of the main injection process, the injection pulse width of diesel fuel is greater than that of the pre-injection process.

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