Microwave heating device for methanol engine

Abstract

The invention provides a microwave heating device for a methanol engine, and relates to the technical field of engines, the methanol engine is provided with an oil sprayer suitable for spraying methanol and an air inlet channel for mixing methanol and air, and the microwave heating device comprises a transmission pipeline, a microwave constraint cavity and a microwave generating mechanism. An inlet of the conveying pipeline is connected with the oil sprayer, and an outlet is connected to the air inlet channel and suitable for methanol to flow. The transmission pipeline is coaxially sleeved with the microwave restraining cavity, and the microwave restraining cavity is constructed to restrain microwave energy to the periphery of the transmission pipeline. The microwave generating mechanism is suitable for emitting microwaves into the microwave confinement cavity, and the transmission pipeline is configured to allow the microwaves in the microwave confinement cavity to pass through so as to heat methanol.

Description

Technical Field

[0001] This invention relates to the field of engine technology, and more specifically, to a microwave heating device for a methanol engine. Background Technology

[0002] Methanol, as a basic chemical raw material and an emerging alternative fuel, has become a research hotspot in the field of alternative fuels for internal combustion engines due to its wide availability, high oxygen content, and clean combustion. Compared with traditional gasoline and diesel, methanol fuel has physicochemical properties such as high octane number, fast flame propagation speed, and large latent heat of vaporization. These properties enable it to significantly reduce the raw emissions of carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx) while improving engine thermal efficiency.

[0003] However, methanol fuel has a low calorific value, approximately 45% to 50% of that of gasoline, and suffers from problems such as high auto-ignition temperature, strong corrosiveness, and difficulty in cold starting at low temperatures. Furthermore, the M-series fuels (such as M15 and M85) formed by blending methanol and gasoline, and pure methanol fuel (M100), differ significantly in fuel supply system compatibility, lubricant dilution, and emission characteristics of unconventional pollutants (such as formaldehyde and unburned methanol), limiting their direct substitution application in traditional engines.

[0004] Methanol engines, developed based on the characteristics of methanol fuel, represent a key technological path to achieving efficient and low-carbon power output. Existing methanol engines typically employ strategies such as increasing the compression ratio, turbocharging direct injection, and cold-start assistance to compensate for methanol's low calorific value and improve its low-temperature evaporation performance. For example, installing intake air preheating devices or fuel heater plugs addresses the starting challenges of methanol engines in low-temperature environments. However, these heating methods suffer from drawbacks such as high thermal inertia, uneven heating, slow response speed, and low heating efficiency. Especially for methanol fuels requiring instantaneous and uniform vaporization to improve cold-start performance, the efficiency and effectiveness of traditional heating methods are unsatisfactory. Therefore, there is an urgent need to improve existing methanol engines to solve at least some of the aforementioned problems. Summary of the Invention

[0005] In view of this, the present invention provides a microwave heating device for methanol engines, which uses microwaves to heat methanol in bulk, resulting in uniform heating and rapid response, enabling methanol to be fully vaporized and effectively solving the problems of difficult cold start and unstable combustion in engines.

[0006] To achieve the above objectives, the present invention provides a microwave heating device for a methanol engine, the methanol engine having an injector suitable for injecting methanol and an air intake for mixing methanol with air. The microwave heating device includes: a transmission pipe, the inlet of which is connected to the injector and the outlet of which is connected to the air intake, suitable for supplying methanol flow; a microwave confinement cavity, coaxially sleeved outside the transmission pipe, configured to confine microwave energy around the transmission pipe; and a microwave generating mechanism suitable for emitting microwaves into the microwave confinement cavity. The transmission pipe is configured to allow microwaves within the microwave confinement cavity to pass through, thereby bulk heating the methanol.

[0007] According to an embodiment of the present invention, a microwave modulation mechanism is further included, disposed within the microwave confinement cavity, and configured to rotate in an energized state to change the microwave field distribution within the microwave confinement cavity.

[0008] According to an embodiment of the present invention, the microwave modulation mechanism includes: a drive motor; and a stirrer having a plurality of metal blades connected to the output end of the drive motor, adapted to rotate under the drive of the drive motor.

[0009] According to an embodiment of the present invention, the device further includes a housing, through which the transmission conduit is disposed, and the microwave generating mechanism is disposed within the housing.

[0010] According to an embodiment of the present invention, the microwave generating mechanism includes: a magnetron, installed on the inner wall of the housing, and adapted to emit microwaves; a waveguide, one end of which is connected to the magnetron and the other end of which is connected to the microwave confinement cavity, adapted to guide the microwaves emitted by the magnetron into the microwave confinement cavity.

[0011] According to an embodiment of the present invention, a microwave suppression unit is further included, which is sleeved at the outlet of the transmission channel and sandwiched between the microwave confinement cavity and the outer shell, and is suitable for suppressing microwave leakage into the air inlet or the outer shell.

[0012] According to an embodiment of the present invention, the microwave suppression unit includes a ring choke coil.

[0013] According to an embodiment of the present invention, the above-mentioned transmission pipe is constructed to be made of alumina ceramic or quartz glass.

[0014] The microwave heating device for methanol engines provided by this invention delivers high-frequency microwave energy generated by a microwave generator into a microwave confinement cavity. Under the influence of the microwave confinement cavity, the microwave energy is effectively concentrated around the transmission pipe and penetrates the pipe wall, directly acting on the flowing methanol droplets to achieve rapid and uniform volumetric heating, thus promoting the rapid vaporization of the methanol droplets. This process features high heating efficiency, rapid response, almost no thermal inertia, and ensures uniform heating, effectively overcoming the problems of cold start difficulties and unstable combustion caused by the high latent heat of fuel vaporization in methanol engines. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the principle of a microwave heating device for a methanol engine provided by an exemplary embodiment of the present invention.

[0016] In the accompanying drawings, the meanings of the reference numerals are as follows:

[0017] 1. Transmission pipeline;

[0018] 2. Microwave-confined cavity;

[0019] 3. Microwave generating mechanism;

[0020] 31. Magnetron;

[0021] 32. Waveguide;

[0022] 4. Microwave modulation mechanism;

[0023] 41. Drive motor;

[0024] 42. Stirrer;

[0025] 5. Outer casing;

[0026] 6. Microwave suppression unit. Detailed Implementation

[0027] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the invention. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the invention for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0028] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0029] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0030] When using expressions such as "at least one of A, B and C", they should generally be interpreted in accordance with the meaning that is commonly understood by those skilled in the art (e.g., "a system having at least one of A, B and C" should include, but is not limited to, a system having A alone, a system having B alone, a system having C alone, a system having A and B, a system having A and C, a system having B and C, and / or a system having A, B and C, etc.).

[0031] Figure 1 This is a schematic diagram of the principle of a microwave heating device for a methanol engine provided by an exemplary embodiment of the present invention.

[0032] Embodiments of the present invention provide a microwave heating device for a methanol engine, such as... Figure 1 As shown, the methanol engine has an injector suitable for injecting methanol and an intake duct for mixing methanol with air. The microwave heating device includes a transmission pipe 1, a microwave confinement cavity 2, and a microwave generating mechanism 3. The inlet of the transmission pipe 1 is connected to the injector, and the outlet is connected to the intake duct, suitable for supplying methanol flow. The microwave confinement cavity 2 is coaxially sleeved outside the transmission pipe 1 and is configured to confine microwave energy around the transmission pipe 1. The microwave generating mechanism 3 is adapted to emit microwaves into the microwave confinement cavity 2, and the transmission pipe 1 is configured to allow microwaves within the microwave confinement cavity 2 to pass through, thereby bulk heating the methanol.

[0033] like Figure 1 As shown, the transmission pipe 1 and the microwave confinement cavity 2 are arranged approximately coaxially. The microwave confinement cavity 2 is constructed as an annular closed cavity made of a metal material (such as aluminum alloy or stainless steel), which is coaxially fixed to the outer periphery of the middle section of the transmission pipe 1 by high-temperature resistant heat-insulating brackets set at both ends. The microwave confinement cavity 2 extends from the inlet end of the transmission pipe 1 to one side to connect with the fuel injector; the microwave confinement cavity 2 extends from the outlet end to the other side to connect with the engine's air intake.

[0034] In this implementation, methanol, as a polar fuel, has an extremely high latent heat of vaporization, making it difficult to rapidly absorb heat and vaporize during cold starts at low temperatures. During operation, the microwave generator 3 generates high-frequency microwave energy and introduces it into the microwave confinement cavity 2. Due to the confinement effect of the microwave confinement cavity 2, the microwave energy is concentrated around the transmission pipe 1. The microwave energy penetrates the wall of the transmission pipe 1 and directly acts on the methanol droplets flowing within it. The microwave field causes the polar methanol molecules to vibrate and rub at high frequencies, thereby instantly generating a large amount of heat within the fluid, achieving rapid and uniform volume heating, and causing the methanol droplets to vaporize quickly. This method offers high heating efficiency, fast response speed, almost no thermal inertia, and uniform heating, effectively solving the problems of difficult cold starts and unstable combustion caused by the high latent heat of vaporization in methanol engines.

[0035] In one exemplary embodiment, such as Figure 1 As shown, the microwave heating device for methanol engines also includes a housing 5, a transmission pipe 1 that passes through the housing 5, and a microwave generating mechanism 3 that is disposed inside the housing 5.

[0036] like Figure 1 As shown, the outer casing 5 is constructed as a generally cylindrical thin-walled metal shell, coaxially fitted outside the microwave confinement cavity 2. Connecting flanges may be provided at both ends of the outer casing 5 for fixing and sealing with relevant components of the engine intake system. The two ends of the transmission pipe 1 extend outwards through end caps at both ends of the outer casing 5.

[0037] In this implementation, the outer casing 5 provides physical isolation and environmental protection for the internal components, preventing external dust, oil, or mechanical collisions from damaging the microwave generating mechanism 3 and the microwave confinement cavity 2. At the same time, it plays a good role in electromagnetic shielding spillover, improving the reliability and safety of the device in the complex engine compartment environment.

[0038] In one exemplary embodiment, such as Figure 1 As shown, the microwave heating device for methanol engines also includes a microwave modulation mechanism 4, which is disposed in the microwave confinement cavity 2 and is configured to rotate in the energized state to change the microwave field distribution in the microwave confinement cavity 2.

[0039] In this implementation, microwaves easily form standing wave fields within the enclosed microwave confinement cavity 2, resulting in wave peaks and troughs in the spatial energy distribution, which may cause uneven heating of methanol within the transmission pipe 1. By setting up a microwave modulation mechanism 4, its rotational motion can continuously break and disturb the original microwave field within the cavity, enabling dynamic and uniform distribution of microwave energy in the circumferential and axial directions. This ensures that methanol flowing through the entire cross-section of the transmission pipe 1 receives consistent microwave irradiation, further improving vaporization uniformity.

[0040] According to embodiments of the present invention, such as Figure 1As shown, the microwave modulation mechanism 4 includes a drive motor 41 and a stirrer 42. The stirrer 42 has multiple metal blades connected to the output end of the drive motor 41 and is adapted to rotate under the drive of the drive motor 41.

[0041] In this implementation, the drive motor 41 provides stable rotational power, and when the stirrer 42 with multiple metal blades rotates in the microwave field, its metal surface generates strong reflection, scattering, and diffraction effects on the microwaves. The dynamic metal disturbance structure can effectively stir complex electromagnetic fields in a simple mechanical way, with a compact structure and obvious modulation effect.

[0042] In some alternative embodiments, the metal blades of the stirrer 42 are configured in an asymmetrical fan shape. The main body of the drive motor 41 is fixed to the outside of the housing 5, and its output shaft extends into the cavity through the housing 5 and the side wall of the microwave confinement cavity 2, and is connected to the stirrer 42 for transmission. To prevent microwave leakage from the through hole of the output shaft, an anti-flow sealing structure is provided at the junction of the output shaft and the side wall of the microwave confinement cavity 2.

[0043] In some alternative embodiments, the drive motor 41 may be arranged inside the housing 5, preferably outside the housing 5, to reduce interference with the microwave field. Figure 1 In this embodiment, for ease of demonstration, the drive motor 41 is located inside the housing 5. It is understood that, however, the embodiments of the present invention are not limited thereto.

[0044] In some alternative embodiments, the stirrer 42 is mounted to the housing 5 via a bearing seat.

[0045] In one exemplary embodiment, such as Figure 1 As shown, the microwave generating mechanism 3 includes a magnetron 31 and a waveguide 32. The magnetron 31 is mounted on the inner wall of the housing 5 and is used to emit microwaves. One end of the waveguide 32 is connected to the magnetron 31, and the other end is connected to the microwave confinement cavity 2, which is used to guide the microwaves emitted by the magnetron 31 into the microwave confinement cavity 2.

[0046] Specifically, a feed hole is provided on the sidewall or top of the microwave confinement cavity 2, and the other end of the waveguide 32 is connected to the feed hole and welded to seal it. The waveguide 32 is constructed as a hollow metal tube with a specific cross-sectional size (preferably a rectangular cross-section).

[0047] In this implementation, the magnetron 31 acts as a microwave source to convert electrical energy into microwave energy, while the waveguide 32 forms a low-loss microwave transmission channel, ensuring that microwaves can be fed into the microwave confinement cavity 2 with high transmission efficiency, directionality, and no leakage, thus avoiding random reflections of microwaves in the internal space of the outer shell 5 that could lead to energy attenuation or the formation of local hot spots that could burn out non-target components.

[0048] In one exemplary embodiment, such as Figure 1 As shown, the microwave heating device for methanol engines also includes a microwave suppression unit 6, which is sleeved at the outlet of the transmission pipe 1 and sandwiched between the microwave confinement cavity 2 and the outer shell 5, and is suitable for suppressing microwave leakage into the air intake or the outer shell 5.

[0049] In this implementation, the microwave suppression unit 6 is constructed as a ring structure surrounding the transmission pipe 1. One axial end of the unit abuts against the opening face of the microwave confinement cavity 2, and the other axial end abuts against the corresponding side wall or positioning step surface inside the housing 5. The outlet of the transmission pipe 1 needs to connect with the metal intake of the engine. If the high-frequency microwaves in the microwave confinement cavity 2 radiate outward along the pipe, it will not only reduce the effective heating power of methanol but also cause serious electromagnetic interference to the sensors and electronic control units at the rear end of the intake, and may even cause microwave radiation damage to maintenance personnel. The microwave suppression unit 6 is located at the critical position of the outlet. Through a specific geometric design, such as a ring groove with a depth of one-quarter wavelength, a large impedance is presented at the groove opening, thereby reflecting the microwaves attempting to leak outward back into the microwave confinement cavity 2, forming a microwave sealing barrier at the opening, ensuring the overall electromagnetic compatibility and absolute safety of the device.

[0050] It should be noted that those skilled in the art can perform adaptive impedance matching calculations and designs for the geometric parameters such as the slot depth and slot width of the microwave suppression unit 6 based on parameters such as the microwave operating frequency (e.g., 2450MHz or 915MHz) and the outer diameter of the transmission pipe 1. These will not be elaborated upon here.

[0051] According to an embodiment of the present invention, the microwave suppression unit 6 includes a ring choke coil.

[0052] In this implementation, the annular choke coil is constructed as a metal structure with an annular groove, coaxially fitted onto the outer wall of the transmission pipe 1. This groove forms a radially extending anti-flow gap. When sandwiched between the microwave confinement cavity 2 and the outer shell 5, its inductance and distributed capacitance, equivalent to its own structure, constitute a low-pass filter, effectively blocking the outward propagation of electromagnetic waves in the microwave frequency band. Simultaneously, because it is a passive, pure metal static structure, it does not increase the control complexity of the system and exhibits high structural stability and lifespan under the high temperature and vibration conditions of the engine.

[0053] In one exemplary embodiment, the transmission conduit 1 is configured to be made of alumina ceramic or quartz glass.

[0054] In this implementation, both alumina ceramic and quartz glass are typical microwave-transparent media, exhibiting extremely low microwave energy absorption and reflectivity, ensuring that microwave energy penetrates the transmission pipe 1 with maximum penetration and acts on the methanol. Simultaneously, both materials possess excellent high-temperature resistance, capable of withstanding the high-temperature backflow thermal shock that methanol may encounter in the engine intake manifold; and they are resistant to methanol corrosion, preventing chemical erosion of the inner wall by liquid methanol, thus guaranteeing the service life and stability of the transmission pipe 1 under long-term, harsh operating conditions. It should be noted that the transmission pipe 1 and the microwave confinement cavity 2 can be coaxially positioned and supported by a high-temperature resistant heat-insulating bracket to prevent direct rigid contact between the transmission pipe 1 and the metallic microwave confinement cavity 2 during thermal expansion, which could lead to the ceramic tube shattering.

[0055] It should be noted that, due to the difference in the coefficient of linear expansion between ceramic or glass materials and the microwave confinement cavity 2 made of metal, the transmission pipe 1 and the microwave confinement cavity 2 are coaxially positioned and flexibly connected by a high-temperature resistant heat-insulating bracket. This not only achieves relative fixation between the two, but also effectively blocks the heat conduction from the microwave confinement cavity 2 to the transmission pipe 1, prevents the outer wall of the transmission pipe 1 from overheating, and allows the two to produce slight relative sliding when heated, preventing the ceramic tube from being crushed by the metal cavity due to thermal stress.

[0056] In some alternative embodiments, the thermal insulation support is made of, but is not limited to, mica or ceramic fiber.

[0057] Those skilled in the art will understand that the features described in the various embodiments of the present invention can be combined and / or combined in various ways, even if such combinations or combinations are not explicitly described in the present invention. In particular, the features described in the various embodiments of the present invention can be combined and / or combined in various ways without departing from the spirit and teachings of the present invention. All such combinations and / or combinations fall within the scope of the present invention.

[0058] The embodiments of the present invention have been described above. However, these embodiments are merely illustrative and not intended to limit the scope of the invention. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of the invention, and all such substitutions and modifications should fall within the scope of the invention.

Claims

1. A microwave heating device for a methanol engine, the methanol engine having an injector suitable for injecting methanol and an air intake for mixing methanol and air, characterized in that, include: A transmission pipeline, the inlet of which is connected to the fuel injector and the outlet of which is connected to the air intake, is suitable for supplying methanol flow; A microwave confinement cavity, coaxially fitted outside the transmission pipe, is configured to confine microwave energy around the transmission pipe. A microwave generating mechanism is adapted to emit microwaves into the microwave confinement cavity, wherein the transmission conduit is configured to allow microwaves within the microwave confinement cavity to pass through for bulk heating of methanol.

2. The microwave heating device for a methanol engine according to claim 1, characterized in that, It also includes a microwave modulation mechanism, which is disposed within the microwave confinement cavity and is configured to rotate in an energized state to change the microwave field distribution within the microwave confinement cavity.

3. The microwave heating device for a methanol engine according to claim 2, characterized in that, The microwave modulation mechanism includes: Drive motor; The stirrer has multiple metal blades connected to the output end of the drive motor and is adapted to rotate under the drive of the drive motor.

4. The microwave heating device for a methanol engine according to claim 1, characterized in that, It also includes a housing, through which the transmission pipe is disposed, and within the housing the microwave generating mechanism is disposed.

5. The microwave heating device for a methanol engine according to claim 4, characterized in that, The microwave generating mechanism includes: A magnetron, installed on the inner wall of the housing, is suitable for emitting microwaves; A waveguide, one end of which is connected to the magnetron and the other end of which is connected to the microwave confinement cavity, is used to guide microwaves emitted by the magnetron into the microwave confinement cavity.

6. The microwave heating device for a methanol engine according to claim 4, characterized in that, It also includes a microwave suppression unit, which is sleeved at the outlet of the transmission pipe and sandwiched between the microwave confinement cavity and the outer shell, and is suitable for suppressing microwave leakage into the air inlet or the outer shell.

7. The microwave heating device for a methanol engine according to claim 6, characterized in that, The microwave suppression unit includes a ring choke coil.

8. The microwave heating device for a methanol engine according to any one of claims 1-7, characterized in that, The transmission pipe is constructed of alumina ceramic or quartz glass.

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