Cold start device for a marine pure methanol manifold injection spark ignition engine

Abstract

The application discloses a cold starting device of a pure methanol manifold injection ignition engine for a ship, which comprises an injection unit and a mixed gas preheating unit. One end of an air inlet pipe is connected with an air inlet port of a cylinder cover through the injection unit, an intermediate connecting pipe, annular plates at two ends of the mixed gas preheating unit, the mixed gas preheating unit, an air inlet pipe of the cylinder cover and the air inlet port of the cylinder cover in sequence. The injection unit comprises an injection unit pipe, a methanol fuel atomization arc-shaped plate and MCH ceramic electric heating arc-shaped pieces. The outer surface of the methanol fuel atomization arc-shaped plate towards the axis of the injection unit pipe is provided with a plurality of atomization spherical pits with heads cut off in a matrix arrangement. The mixed gas preheating unit comprises a double-wall pipe, annular plates and a plurality of MCH ceramic electric heating rods. The injection unit of the application atomizes methanol fuel droplets through secondary atomization, significantly improves the atomization characteristics of the methanol fuel and the temperature of the mixed gas in the annular cavity, and further ensures the cold starting of the pure methanol fuel engine to be completed quickly and efficiently.

Description

Technical Field

[0001] This invention relates to a new energy engine, and more particularly to a starting device for a marine pure methanol fuel engine, belonging to the field of new energy engine technology. Background Technology

[0002] Methanol fuel, as a carbon-neutral clean energy source, boasts advantages such as high octane rating and high oxygen content. Compared to the harmful substances produced by petroleum combustion, methanol fuel combustion significantly reduces harmful emissions, making it a promising candidate for marine engines. However, it also exhibits a high latent heat of vaporization, posing challenges for cold starts in marine engines, regardless of whether it's injected directly or via manifold. Poor vaporization of methanol fuel after intake manifold injection often results in it entering the cylinder in liquid form, diluting the lubricating oil and lowering cylinder temperature at 10%–30% and 30%–70% loads. This can cause the flame front to quench on the cylinder wall, leading to incomplete combustion and other problems.

[0003] Currently, methanol fuel is mostly used in a dual-fuel mode, employing gasoline or diesel as pilot fuel and controlling the methanol substitution rate to achieve methanol fuel replacement. This dual-fuel mode results in a relatively complex marine engine layout and requires two fuel supply systems, increasing manufacturing costs. Although using dedicated injectors can improve atomization characteristics, the inherently high latent heat of vaporization of methanol remains unchanged. Furthermore, fuel heating methods, intake air heating methods, and combined fuel-intake-air heating methods have not fundamentally changed, and the cold start problem remains unresolved. Summary of the Invention

[0004] The purpose of this invention is to provide a cold start device for a marine pure methanol manifold injection spark engine, which aims to solve the problems of poor methanol fuel atomization during the cold start phase of a pure methanol fuel engine, resulting in difficulty in starting, incomplete combustion, and unstable combustion.

[0005] This invention is achieved through the following technical solution:

[0006] A cold start device for a marine pure methanol manifold injection spark-ignition engine, characterized in that it includes an injection unit and a mixture preheating unit. One end of the intake pipe is connected to the cylinder head intake port via the injection unit, an intermediate connecting pipe, annular plates at both ends of the mixture preheating unit, the mixture preheating unit, and the cylinder head port intake pipe. The injection unit includes an injection unit pipe, a methanol fuel atomizing arc plate, and MCH ceramic electric heating arc plates. Methanol injector mounting joints are respectively provided on the radially downward sides of both ends of the injection unit pipe. The axes of the two methanol injector mounting joints form an α angle of 40° to 50° with the cross center line of the corresponding cross section of the injection unit pipe. The two injection unit tubes, which are opposite to the two α angles, have concave semi-circular through grooves on their inner circumferential surfaces. The MCH ceramic electric heating arc plate and the methanol fuel atomizing arc plate are embedded and fixed in the semi-circular through grooves, one inside and one outside. The axes of the two methanol injector bodies and the arc of the methanol fuel atomizing arc plate form a fan shape facing the methanol fuel atomizing arc plate. The center hole of the methanol injector mounting joint is connected to the through hole that passes through the MCH ceramic electric heating arc plate and the methanol fuel atomizing arc plate in sequence. The outer surface of the methanol fuel atomizing arc plate facing the axis of the injection unit tube has multiple atomizing spherical pits with their heads cut off, arranged in a matrix.

[0007] The mixed gas preheating unit includes a double-walled tube consisting of an outer wall tube and an inner wall tube, an annular plate located at both ends of the double-walled tube, and multiple MCH ceramic heating rods. Multiple rectangular convex frames are evenly distributed on the outer circumference of the inner wall tube. The MCH ceramic heating rods are respectively inserted and fixed in the rectangular convex frames. The exhaust gas inlet connector and the exhaust gas return connector are respectively set at the two ends of the outer wall tube, one above the other. The exhaust connector on the upper side of the exhaust pipe connected to the cylinder head exhaust port is connected to the exhaust gas inlet connector on the upper side of one end of the outer wall tube in sequence through the bypass electronic throttle valve and the exhaust gas bypass pipe. The return connector on the lower side of the other end of the outer wall tube is connected to the exhaust pipe return connector on the lower side of the exhaust pipe through the exhaust gas return pipe. The annular plate is provided with a heating plate wire harness connector on the radial outer side.

[0008] The objectives of this invention can also be further achieved through the following technical measures.

[0009] Furthermore, the first thermocouple temperature sensor is connected in parallel to the intake pipe connected to one end of the injection unit pipe; the second and third thermocouple temperature sensors are connected in parallel to the intermediate intake pipe and the cylinder head port intake pipe, respectively; and the fourth thermocouple temperature sensor is connected in parallel to the exhaust bypass pipe; the signal lines of each thermocouple temperature sensor and the electronic throttle valve are connected to the engine ECU.

[0010] Furthermore, the diameter of the spherical pit with the smaller outer part and larger inner part removed is D = 5-6 mm, the vertical distance from the center of the atomizing spherical pit to the outer circumference of the MCH ceramic electric heating arc plate is L = 0.3-0.4D, and the center distance between the atomizing spherical pits is B = 1.25-1.5D.

[0011] Furthermore, a nano-high temperature resistant coating material that can withstand temperatures above 200℃ is applied to the inner circumferential surface of the outer wall tube and the inner surface of the heating plate wire harness connector of the annular plate.

[0012] Furthermore, the intake pipe, injection unit pipe, intermediate connecting pipe, annular plate, outer wall pipe, and cylinder head port intake pipe have the same outer diameter. Several connecting lugs are evenly distributed radially on the intake pipe, injection unit pipe, intermediate connecting pipe, annular plate, outer wall pipe, and cylinder head port intake pipe. Adjacent connecting lugs are fixedly connected by fasteners, thereby fixing the intake pipe, injection unit pipe, intermediate connecting pipe, annular plate, outer wall pipe, and cylinder head port intake pipe into a whole.

[0013] This invention features methanol injector mounting connectors radially positioned at both ends of the injection unit tube. The methanol injectors intersect the cross-sectional center lines of the corresponding sections of the injection unit tube at acute angles of 40° to 50°. The two methanol injectors spray towards the methanol fuel atomizing arc plate heated by the MCH ceramic electric heating plate, forming an "umbrella-shaped" spray surface. This ensures the methanol fuel is evenly injected into multiple matrix-arranged atomizing spherical depressions. Utilizing the injection pressure and gravity of the methanol fuel, it is heated and vaporized. As the hot methanol fuel disperses and impacts the atomizing spherical depressions, the fuel jet drives airflow, creating a vertically outward air column within the heated depressions. This results in a high vaporization rate for the methanol fuel, aiding in the breaking up of methanol fuel droplets and forming secondary atomization, significantly improving the atomization characteristics of the methanol fuel and enhancing the reliability of cold starts for pure methanol fuel engines.

[0014] This invention forms a two-stage preheating channel in the cavity between the inner and outer wall tubes of the double-walled tube of the gas-mixture preheating unit. The first-stage preheating channel is located between the adjacent faces of each rectangular convex frame and is provided with a preheating heat source by an MCH ceramic heating rod. The second-stage preheating channel is an annular cavity, provided with a heat source by high-temperature exhaust gas introduced through the exhaust gas bypass pipe. Depending on the cold start requirements of different operating conditions, the two-stage preheating channels can be activated separately or simultaneously, allowing each stage to independently, directly, and efficiently preheat the methanol fuel flowing inside the inner wall tube. This significantly increases the temperature of the gas-mixture mixture within the annular cavity, thereby ensuring a rapid and efficient cold start for the pure methanol fuel engine.

[0015] The advantages and features of the present invention will be illustrated and explained by the following non-limiting description of preferred embodiments, which are given by way of example only with reference to the accompanying drawings. Attached Figure Description

[0016] Figure 1 This is a simplified structural diagram of the present invention;

[0017] Figure 2 This is a three-dimensional view of the injection unit;

[0018] Figure 3 This is a top view of the injection unit;

[0019] Figure 4 An enlarged view of the methanol fuel atomizing arc plate unfolded into a flat plate;

[0020] Figure 5 for Figure 4 A magnified view of a portion of the view from direction A;

[0021] Figure 6 This is a 3D view of a double-walled tube;

[0022] Figure 7 This is an end view of a double-walled pipe;

[0023] Figure 8 This is the front view of the annular plate. Detailed Implementation

[0024] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0025] In the description of this invention, it should be understood that the terms "center", "longitudinal", "lateral", "upper", "lower", "axial", "radial", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0026] like Figure 1 As shown, in this embodiment, the cylinder head 10 of a pure methanol fuel engine is installed on both sides. The cylinder head 10 is axially equipped with an intake valve 201 and an exhaust valve 202 whose movement is controlled by a cam system. A spark plug 203 is installed at the axial center of the cylinder head 10.

[0027] like Figures 1 to 8 As shown, this embodiment includes an injection unit 1 and a mixture preheating unit 2. The right end of the intake pipe 20 is connected to the cylinder head intake port 101 by the injection unit 1, the intermediate connecting pipe 3, the annular plates 4 at both ends of the mixture preheating unit 2, the mixture preheating unit 2, the cylinder head port intake pipe 5, and the injection unit 1. The injection unit 1 includes an injection unit pipe 11, a methanol fuel atomizing arc plate 12, and an MCH (metal-ceramic heating element) ceramic electric heating arc plate 13. Methanol injector mounting joints 111 are provided on the radially downward sides of both ends of the injection unit pipe 11, and methanol injectors 8 are fixed on the methanol injector mounting joints 111.

[0028] like Figures 2-5As shown, the axes of the two methanol injector mounting joints 111 intersect the cross-shaped center line of the corresponding cross section of the injection unit tube 11 at an angle of 45° α. A concave semi-circular arc groove 112 is provided on the inner circumferential surface of the injection unit tube 11 opposite to the two α angles. The MCH ceramic electric heating arc plate 13 and the methanol fuel atomizing arc plate 12 are sequentially embedded in the semi-circular arc groove 112, one inside and one outside. Mounting ears 121 extend from both ends of the methanol fuel atomizing arc plate 12 at intervals. Fastening screws 14 pass through the mounting ears 121 and are screwed into the injection unit tube 11, thereby fixing the MCH ceramic electric heating arc plate 13 and the methanol fuel atomizing arc plate 12 to the inner wall of the injection unit tube 1. The axes of the two methanol injector bodies 14 and the arc of the methanol fuel atomizing arc plate 12 form a fan shape facing the methanol fuel atomizing arc plate 12, increasing the injection area of ​​the methanol injector body 14. The center hole 113 of the methanol injector mounting connector 111 is connected to the through hole 123 that passes through the MCH ceramic electric heating arc plate 13 and the methanol fuel atomizing arc plate 12 in sequence. The outer surface of the methanol fuel atomizing arc plate 12 facing the axis of the injection unit tube 11 is provided with a plurality of atomizing spherical recesses 122, each with its head cut off, arranged in a matrix.

[0029] In this embodiment, the spherical diameter D of the atomizing spherical pit 122, which is smaller on the outside and larger on the inside, is removed.

[0030] =6mm, the center distance of the atomizing spherical pit 122 from the outer circumferential surface of the MCH ceramic electric heating arc plate 12 is L = 0.3~0.4D, and the center distance between the atomizing spherical pits 122 is B = 1.25~1.5D. This structure significantly improves the atomization effect of methanol fuel.

[0031] like Figure 6 and Figure 7 As shown, the air-fuel mixture preheating unit 2 includes a double-walled tube 21 composed of an outer wall tube 211 and an inner wall tube 212, annular plates 4 located at both ends of the double-walled tube 21, and multiple MCH ceramic heating rods 23. Multiple rectangular protruding frames 213 are evenly distributed on the outer circumference of the inner wall tube 212. The MCH ceramic heating rods 23 are inserted and fixed in the rectangular protruding frames 213. Exhaust gas inlet connector 214 and exhaust gas return connector 215 are respectively installed at both ends of the outer wall tube 211, one above the other. The exhaust connector 301 on the upper side of the exhaust pipe 30, which is connected to the cylinder head exhaust port 102, is connected to the exhaust gas inlet connector 214 on the upper right end of the outer wall tube 211 via a bypass electronically controlled throttle valve 24 and an exhaust gas bypass pipe 25. The exhaust gas return connector 215 on the lower left end of the outer wall tube 211 is connected to the exhaust pipe return connector 302 on the lower side of the exhaust pipe 30 via a tail gas return pipe 26. Figure 8 As shown, the annular plate 4 has a heating plate wire harness connector 41 on its radially outer side.

[0032] like Figure 7As shown, the cavity between the outer wall tube 211 and the inner wall tube 212 is divided into two-stage preheating channels. The first-stage preheating channel is formed between the outer circumferential surfaces of each rectangular convex frame 213 and the outer circumferential surface of the inner wall tube 212, with heat provided by the MCH ceramic heating rod 23. The second-stage preheating channel is formed by the inner circumferential surface of the outer wall tube 211 and the outer edge of the rectangular convex frame 213, with heat provided by the high-temperature waste gas introduced through the waste gas bypass pipe 25. The first-stage and second-stage preheating channels can be used independently or in combination to increase the temperature of the mixed gas.

[0033] like Figure 1 In the direction indicated by the middle arrow, the methanol fuel input from the intake pipe 20 is fully atomized by the injection unit 1, then preheated by the two-stage preheating channel of the mixture preheating unit 2, and then injected into the cylinder 40 through the cylinder head 10, providing a reliable guarantee for completing the cold start of the pure methanol fuel engine.

[0034] like Figure 1 As shown, the first thermocouple temperature sensor 61 is connected in parallel to the intake pipe 10, which is connected to the left end of the injection unit pipe 111. The second thermocouple temperature sensor 62 and the third thermocouple temperature sensor 63 are connected in parallel to the intermediate intake pipe 3 and the cylinder head port intake pipe 5, respectively. The fourth thermocouple temperature sensor 64 is connected in parallel to the exhaust gas bypass pipe 25. The signal lines 71 of each thermocouple temperature sensor and the signal line 72 of the electronic throttle valve are connected to the engine ECU. The thermocouple temperature sensors are used to detect the temperature of the outer cavity of the injection unit 1 and the mixture preheating unit 2, as well as the temperature of the exhaust gas in the exhaust gas bypass pipe 25, and feed the feedback to the engine ECU 100. The engine ECU 100 issues corresponding commands to complete the cold start of the pure methanol fuel engine.

[0035] The intake pipe 20, injection unit pipe 11, intermediate connecting pipe 3, annular plate 4, outer wall pipe 211, and cylinder head port intake pipe 5 have the same outer diameter. The intake pipe 20, injection unit pipe 11, intermediate connecting pipe 3, annular plate 4, outer wall pipe 211, and cylinder head port intake pipe 5 are each radially evenly distributed with three connecting lugs 31. Adjacent connecting lugs 31 are fixedly connected by fasteners 32, thereby fixing the intake pipe 20, injection unit pipe 11, intermediate connecting pipe 3, annular plate 4, outer wall pipe 211, and cylinder head port intake pipe 5 into a whole.

[0036] The inner circumferential surface of the outer wall tube 211 and the inner surface of the heating plate wire harness connector 41 of the annular plate 4 are coated with a nano high-temperature resistant coating material that can withstand temperatures above 200℃, thereby improving the high-temperature resistance of the injection unit 1 and the mixed gas preheating unit 2.

[0037] The working process of this invention is as follows:

[0038] When the engine ECU100 detects that the pure methanol fuel engine is in a cold start and the first thermocouple temperature sensor 61 reports that the intake air temperature is below 15°C, the engine ECU instructs the MCH ceramic electric heating arc plate 13 of the injection unit 1 to rapidly heat up to 80°C within 1 second, and rapidly heat up the MCH ceramic electric heating rod 23 of the first-stage preheating channel to 100°C within 2 seconds and continue heating until the pure methanol fuel engine starts and runs normally.

[0039] When the engine ECU100 detects that the pure methanol fuel engine is in a cold start and the first thermocouple temperature sensor 61 reports that the intake air temperature is higher than 15°C, the engine ECU instructs the MCH ceramic electric heating arc plate 13 to rapidly heat up to 60°C within 1 second, and at the same time rapidly heat up the MCH ceramic electric heating rod 23 to 80°C within 2 seconds and continue heating until the pure methanol fuel engine starts and runs normally.

[0040] When the engine ECU100 detects that the pure methanol fuel engine is running at a load of 10% to 30%, the engine ECU instructs the MCH ceramic heating rod 23 to continuously maintain the temperature at 60°C.

[0041] When the engine ECU100 detects that the pure methanol fuel engine is under 30% to 70% load, the engine ECU instructs the MCH ceramic heating rod 23 to stop heating, and at the same time instructs the MCH ceramic electric heating arc plate 13 to continue to control the temperature to 40°C. At this time, the engine ECU100 instructs the electronically controlled throttle valve 24 to open, and part of the high-temperature exhaust gas is delivered to the exhaust gas intake connector 214 through the electronically controlled throttle valve 24. The methanol fuel combustion exhaust gas flows in the second-stage preheating channel formed by the annular cavity 216 in the outer wall pipe 211, and then flows back to the exhaust pipe 30 through the exhaust gas return connector 215, the exhaust gas return pipe 26, and the exhaust pipe return connector 302 in sequence, so as to make full use of the waste heat of the high-temperature exhaust gas. When the fourth thermocouple temperature sensor 64 detects that the intake temperature of the air-fuel mixture preheating unit 2 is too high, the engine ECU 100 instructs to reduce the opening of the electronically controlled throttle valve 24 to reduce the exhaust gas flow rate and lower the exhaust gas temperature leading to the annular cavity 216 of the outer wall pipe 211. By changing the opening of the electronically controlled throttle valve 24, the temperature of the second-stage preheating channel is maintained at 60°C.

[0042] When the engine ECU100 detects that the pure methanol fuel engine is under 70% to 100% load, the engine ECU instructs the MCH ceramic electric heating arc plate 13 of the injection unit 1 to stop heating, and at the same time instructs to increase the opening of the electronically controlled throttle valve 24 to increase the exhaust gas flow, so that the temperature of the second-stage preheating channel is maintained at 80°C.

[0043] In addition to the above embodiments, the present invention may have other implementation methods. All technical solutions formed by equivalent substitution or equivalent transformation fall within the protection scope claimed by the present invention.

Claims

1. A cold start device for a marine pure methanol manifold injection spark engine, characterized in that, The system includes an injection unit and a mixture preheating unit. One end of the intake pipe connects sequentially to the injection unit, an intermediate connecting pipe, annular plates at both ends of the mixture preheating unit, the mixture preheating unit, and the cylinder head intake pipe, all connected to the cylinder head intake port. The injection unit includes an injection unit pipe, a methanol fuel atomizing arc plate, and an MCH ceramic electric heating arc plate. Methanol injector mounting joints are radially located at both ends of the injection unit pipe. The axes of the two methanol injector mounting joints intersect the cross-shaped center line of the corresponding cross section of the injection unit pipe at angles α (40°–50°). The injection unit... The inner circumference of the tube is provided with a concave semi-circular through groove. The MCH ceramic electric heating arc plate and the methanol fuel atomizing arc plate are embedded and fixed in the semi-circular through groove one inside and one outside. The axis of the two methanol injector bodies and the arc of the methanol fuel atomizing arc plate form a fan shape facing the methanol fuel atomizing arc plate. The center hole of the methanol injector mounting joint is connected to the through hole that passes through the MCH ceramic electric heating arc plate and the methanol fuel atomizing arc plate in sequence. The outer surface of the methanol fuel atomizing arc plate facing the axis of the injection unit tube is provided with multiple atomizing spherical pits with their heads cut off, arranged in a matrix. The mixed gas preheating unit includes a double-walled tube consisting of an outer wall tube and an inner wall tube, an annular plate located at both ends of the double-walled tube, and multiple MCH ceramic heating rods. Multiple rectangular convex frames are evenly distributed on the outer circumference of the inner wall tube. The MCH ceramic heating rods are respectively inserted and fixed in the rectangular convex frames. The exhaust gas inlet connector and the exhaust gas return connector are respectively set at both ends of the outer wall tube, one above the other. The exhaust connector on the upper side of the exhaust pipe connected to the cylinder head exhaust port is connected to the exhaust gas inlet connector on the upper side of one end of the outer wall tube in sequence through the bypass electronic throttle valve and the exhaust gas bypass pipe. The exhaust gas return connector on the lower side of the other end of the outer wall tube is connected to the exhaust pipe return connector on the lower side of the exhaust pipe through the exhaust gas return pipe. The annular plate is provided with a heating plate wire harness connector on the radial outer side. The first thermocouple temperature sensor is connected in parallel to the intake pipe connected to one end of the injection unit pipe; the second and third thermocouple temperature sensors are connected in parallel to the intermediate intake pipe and the cylinder head port intake pipe, respectively; and the fourth thermocouple temperature sensor is connected in parallel to the exhaust bypass pipe; the signal lines of each thermocouple temperature sensor and the electronic throttle valve are connected to the engine ECU. The intake pipe, injection unit pipe, intermediate connecting pipe, annular plate, outer wall pipe, and cylinder head port intake pipe have the same outer diameter. Several connecting lugs are evenly distributed radially on the intake pipe, injection unit pipe, intermediate connecting pipe, annular plate, outer wall pipe, and cylinder head port intake pipe. Adjacent connecting lugs are fixedly connected by fasteners, thereby fixing the intake pipe, injection unit pipe, intermediate connecting pipe, annular plate, outer wall pipe, and cylinder head port intake pipe into a whole.

2. The cold start device for a marine pure methanol manifold injection spark-ignition engine as described in claim 1, characterized in that, The diameter of the spherical pit with the smaller outer part and larger inner part removed is D = 5-6 mm, the vertical distance from the center of the spherical pit to the outer circumference of the MCH ceramic electric heating arc plate is L = 0.3-0.4D, and the center distance between the spherical pits is B = 1.25-1.5D.

3. The cold start device for a marine pure methanol manifold injection spark-ignition engine as described in claim 1, characterized in that, The inner circumferential surface of the outer wall tube and the inner part of the heating plate wire harness connector of the annular plate are coated with a nano high-temperature resistant coating material that can withstand temperatures above 200℃.

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