Device for inhibiting tempering of air inlet channel hydrogen injection compression ignition type internal combustion engine

Abstract

The invention relates to a device for inhibiting tempering of an air inlet channel hydrogen injection compression ignition type internal combustion engine, which belongs to the technical field of internal combustion engines and comprises a cylinder body, a piston, an air inlet channel, an exhaust channel, an air inlet valve, an exhaust valve, a direct injection oil injector and a combustion chamber, a semi-circular-arc-shaped impact platform is arranged on the outer side of the top of the double-layer flow dividing combustion chamber, a hydrogen spraying device facing the air inlet valve is obliquely arranged in the air inlet channel, a flow blocking device is arranged below a nozzle of the hydrogen spraying device, and an air inlet gap is formed between the bottom of the flow blocking device and the bottom of the air inlet channel. The flow blocking device is arranged below the hydrogen sprayer, so that the risk of tempering caused by the fact that high-temperature waste gas flows back into the gas inlet channel is effectively reduced. The novel asymmetric combustion chamber design of the single-layer backflow combustion chamber and the double-layer flow dividing combustion chamber is adopted, and the tempering phenomenon of the hydrogen internal combustion engine can also be restrained.

Description

Technical Field

[0001] The present invention belongs to the technical field of internal combustion engines, and more particularly relates to a device for suppressing backfire in an intake port hydrogen injection compression ignition internal combustion engine. Background Art

[0002] With the rapid development of the economy, the use of fossil fuels has led to a large amount of greenhouse gas emissions, causing air pollution and climate change, and seriously damaging human health. Compared with traditional fossil energy, hydrogen, as a new clean energy source, has the characteristics of being renewable, having a large energy density, and not producing pollutants during combustion. Using hydrogen as a fuel is an important way for internal combustion engines to achieve carbon neutrality. Hydrogen fuel internal combustion engines have good combustion performance and broad application prospects.

[0003] Currently, the developed hydrogen internal combustion engines can be divided into intake port hydrogen injection and in-cylinder hydrogen injection according to their injection methods. Among them, intake port hydrogen injection can make hydrogen mix better with air and improve the combustion efficiency of the fuel mixture, which is one of the mainstream development directions of future internal combustion engines. Although intake port hydrogen injection has advantages such as simple structure and low NOx emissions, it also faces challenges. The key to the research and development of hydrogen internal combustion engines not only includes further improving combustion stability but also avoiding the occurrence of backfire.

[0004] The stable combustion of the fuel mixture in the combustion chamber is the key factor to solve the problem. The combustion chamber is the main component that organizes the flow of the in-cylinder fuel mixture and guides the fuel injection path, determining the mixing and combustion process of the fuel-air in the cylinder. Improving the traditional ω-shaped combustion chamber can adjust the in-cylinder flow field, improve the air utilization rate of the cylinder, and thus promote the mixing of fuel and air. However, the clearance volume around the cylinder wall is still not fully utilized, affecting the formation of the final mixture, and the high-temperature area caused by unstable fuel combustion is prone to the risk of backfire. Summary of the Invention

[0005] The present invention provides a device for suppressing backfire in an intake port hydrogen injection compression ignition internal combustion engine to solve the problems existing in the above background art.

[0006] The present invention provides the following technical solutions: A device for suppressing backfire in a hydrogen-injected compression ignition internal combustion engine of an intake passage, comprising a cylinder block, a piston, an intake passage, an exhaust passage, an intake valve, an exhaust valve, and a direct injection fuel injector. A combustion chamber is provided at the top of the piston. The combustion chamber is of a ω shape and is divided into a single-layer recirculation combustion chamber and a double-layer split combustion chamber from the middle. The single-layer recirculation combustion chamber and the double-layer split combustion chamber are respectively close to the intake passage side and the exhaust passage side. An arc-shaped impact platform is provided on the outer side of the top of the double-layer split combustion chamber. A smooth transition arc surface one is provided between the outer side wall of the impact platform and the top of the piston. A hydrogen injector is inclined in the intake passage and is oriented towards the intake valve. A flow blocking device is provided below the nozzle of the hydrogen injector. A support plate parallel to its axis is fixed below the hydrogen injector. The flow blocking device is fixed at the lower end position of the support plate. An intake gap is provided between the bottom of the flow blocking device and the bottom of the intake passage.

[0007] As a preference, the bottom of the combustion chamber is a conical flow guiding platform. An upwardly warped arc-shaped combustion chamber pit is provided on the outer side of the conical flow guiding platform. A smooth transition arc surface two is provided between the top of the combustion chamber pit in the single-layer recirculation combustion chamber and the top of the piston.

[0008] As a preference, the fuel injection on the side of the direct injection fuel injector close to the intake passage is conical fuel injection towards the single-layer recirculation combustion chamber. The fuel injection target on the side of the direct injection fuel injector close to the exhaust passage is located at the cone angle of the inner end edge of the impact platform.

[0009] As a preference, the flow blocking device includes a fixing plate fixed to the support plate. A connecting plate perpendicular to it is fixed on the fixing plate. The other end of the connecting plate is fixed with a baffle plate. A reinforcing rib plate is fixed on the connecting plate.

[0010] As a preference, the baffle plate is a rectangular plate, and the upper plate surface of the rectangular plate is parallel to the axis of the hydrogen injector.

[0011] As a preference, the baffle plate is a trapezoidal plate. The upper plate surface of the trapezoidal plate is parallel to the axis of the hydrogen injector. The distances from the front and back sides of the trapezoidal plate to the vertical central axis of the trapezoidal plate gradually increase from top to bottom.

[0012] As a preference, the baffle plate is an arc-shaped plate, and the side of the arc-shaped plate close to the connecting plate is a convex curve shape.

[0013] As a preference, the middle of the connecting plate and the baffle plate is hinged. A first tension spring is fixed to the back side of the upper end of the baffle plate, and the other end of the first tension spring is fixed to the fixing plate.

[0014] As a preference, the flow blocking device includes a support shaft parallel to the axis of the hydrogen injector. A first iron core that can slide up and down along the axis is sleeved on the support shaft. A connecting sleeve is fixed on the side of the first iron core away from the support plate. A flow blocking plate is connected to the end of the connecting sleeve away from the support plate. Springs are sleeved on the support shaft above and below the first iron core. Support blocks are fixed at both ends of the support shaft, and the support blocks are fixed on the support plate. Electromagnets one symmetrical about the support axis are provided on the upper and lower support blocks.

[0015] As a preference, an electromagnet two is fixed inside the connecting sleeve. A core two that can slide inside the connecting sleeve is arranged outside the electromagnet two. A control rod is fixed to the outer end of the core two. The outer end of the control rod passes through the outer end of the connecting sleeve and is symmetrically hinged with a connecting rod. The baffle includes an outer baffle hinged to the other end of the connecting rod. Sliding cavities are arranged on the opposite sides of the two outer baffles. Sliders are arranged inside the sliding cavities. An inner baffle is fixedly connected between the two sliders. A fixing rod is fixed to the outer side wall of the connecting sleeve. The other end of the fixing rod is fixed to the inner baffle. A second tension spring is fixed to the outer end of the core two. The other end of the second tension spring is fixed to the inner wall of the outer end of the connecting sleeve.

[0016] The technical effects and advantages of the present invention: By arranging a baffle device below the hydrogen injector, the hydrogen diffusion angle is reduced and the time for the fuel mixture to enter the cylinder is shortened. A narrow intake gap is generated between the bottom of the intake passage and the baffle. When air flows through here, the speed increases and the pressure decreases. The pressure difference will cause the hydrogen that may remain above the intake valve to move into the cylinder, reducing the hydrogen concentration accumulated around the intake valve and effectively reducing the risk of backfire caused by the reverse flow of high-temperature exhaust gas into the intake passage. The asymmetric new combustion chamber design of the single-layer reflux combustion chamber and the double-layer split combustion chamber is adopted. The double-layer split combustion chamber realizes the diffusion and combustion of the double-layer fuel mixture, improves the diffusion and combustion rate of the fuel mixture, and inhibits the backfire phenomenon of the hydrogen internal combustion engine. Description of the drawings

[0017] Figure 1 is the front view structural schematic diagram of the present invention; Figure 2 is the internal front view structural schematic diagram of the piston; Figure 3 is the internal three-dimensional structural schematic diagram of the piston; Figure 4 is the structural schematic diagram of the first baffle device; Figure 5 is the structural schematic diagram of the second baffle device; Figure 6 is the structural schematic diagram of the third baffle device; Figure 7 is the structural schematic diagram of the fourth baffle device; Figure 8 is the structural schematic diagram of the fifth baffle device; The reference numerals are: 1, hydrogen injector; 2, vehicle-mounted computer; 3, intake valve; 4, direct injection fuel injector; 5, exhaust valve; 6, combustion chamber; 601, conical flow guide platform; 602, combustion chamber pit; 603, impact platform; 604, smooth transition arc surface I; 605, smooth transition arc surface II; 7, piston; 8, intake passage; 9, flow blocking device; 901, baffle; 902, connecting plate; 903, fixing plate; 904, reinforcing rib plate; 905, tension spring I; 906, iron core I; 907, support block; 908, electromagnet I; 909, spring; 910, connecting sleeve; 911, tension spring II; 912, slider; 913, inner flow blocking plate; 914, fixing rod; 915, connecting rod; 916, outer flow blocking plate; 917, control rod; 918, iron core II; 919, electromagnet II; 10, support plate. Detailed implementation manners

[0018] The present invention will be further described below in conjunction with specific embodiments. However, those skilled in the art should understand that the detailed description given here in conjunction with the accompanying drawings is for better explanation. The structure of the present invention necessarily exceeds these limited embodiments, and for some equivalent replacement schemes or common means, no detailed description will be given herein, but they still fall within the protection scope of the present application.

[0019] Embodiment 1, as Figures 1 to 3 shown, the present invention is a device for suppressing backfire of an intake port hydrogen injection compression ignition internal combustion engine, including a cylinder block, a piston 7, an intake passage 8, an exhaust passage, an intake valve 3, an exhaust valve 5, and a direct injection fuel injector 4. A combustion chamber 6 is provided at the top of the piston 7. The combustion chamber 6 is of a ω shape and is divided into a single-layer recirculation combustion chamber and a double-layer split combustion chamber from the middle. The single-layer recirculation combustion chamber and the double-layer split combustion chamber are respectively close to the side of the intake passage 8 and the side of the exhaust passage. An arc-shaped impact platform 603 is provided on the outer side of the top of the double-layer split combustion chamber. A smooth transition arc surface I 604 is provided between the outer side wall of the impact platform 603 and the top of the piston 7. A hydrogen injector 1 is inclined in the intake passage 8 towards the intake valve 3. A flow blocking device 9 is provided below the nozzle of the hydrogen injector 1. A support plate 10 parallel to its axis is fixed below the hydrogen injector 1. The flow blocking device 9 is fixed at the lower end position of the support plate 10. An intake gap is provided between the bottom of the flow blocking device 9 and the bottom of the intake passage 8.

[0020] In the later stage of the exhaust stroke of the internal combustion engine, the intake valve 3 opens, and air enters the cylinder block from the intake passage 8 to cool the temperature inside the cylinder. During the intake stroke, the piston 7 moves downward. When the piston 7 reaches the injection moment of the hydrogen injector 1, the hydrogen injector 1 injects hydrogen. At this time, most of the hydrogen injected by the hydrogen injector 1 is directly injected into the intake passage 8 to mix with the air, and a small part is blocked by the baffle device 9. When the hydrogen impacts on the baffle device 9, its movement direction will change, causing the hydrogen to accumulate and the movement speed to increase, shortening the time to enter the cylinder. Due to the presence of the baffle device 9, a narrow intake gap appears between the bottom of the intake passage 8 and the baffle device 9. When air passes through, its flow rate will increase and the pressure will decrease. A small amount of hydrogen accumulated around the intake valve 3 will flow from the position with high pressure to the position with low pressure and be carried into the cylinder by the air. Adding the intake gap can reduce the hydrogen diffusion angle at a high hydrogen injection flow rate, effectively solve the problem of hydrogen accumulation around the intake valve 3 during the intake process, prevent the backflow of high-temperature exhaust gas caused by the early opening of the intake valve 3, ignite the mixture accumulated around the intake valve 3, and reduce the risk of backfire of the intake port hydrogen injection compression ignition internal combustion engine.

[0021] Hydrogen and air are preliminarily mixed in the intake passage 8, enter the cylinder through the intake valve 3, and are further mixed with air in the cylinder. Then the piston 7 moves upward. Due to the strong self-diffusivity of hydrogen, a uniform fuel mixture will be formed in the cylinder block before the piston 7 reaches the top dead center. When the piston 7 reaches the injection moment of the direct injection fuel injector 4, the direct injection fuel injector 4 injects diesel. The diesel injected from the fuel injection hole of the direct injection fuel injector 4 facing the intake valve 3 side will be directly injected into the single-layer reentrant combustion chamber and mixed with the fuel mixture. The diesel injected from the fuel injection hole of the direct injection fuel injector 4 facing the exhaust valve 5 side will be injected onto the impact platform 603 to form a fuel stratification. After the diesel is compressed and ignited, it ignites the mixture in the cylinder, pushing the piston 7 downward to do work. Then the exhaust stroke begins, the piston 7 moves upward, the exhaust valve 5 opens, and the exhaust gas generated after combustion enters the exhaust passage, and one cycle of the hydrogen internal combustion engine is completed.

[0022] Embodiment 2, on the basis of Embodiment 1, as Figure 4 shown, the bottom of the combustion chamber 6 is a conical flow guide platform 601, and an upwardly warped circular arc-shaped combustion chamber pit 602 is provided on the outside of the conical flow guide platform 601. A smooth transition arc surface II 605 is provided between the top of the combustion chamber pit 602 in the single-layer reentrant combustion chamber 6 and the top of the piston 7.

[0023] The fuel injection of the direct injection fuel injector 4 on the side close to the intake passage 8 is a conical fuel injection into the single-layer reentrant combustion chamber 6, and the fuel injection target of the direct injection fuel injector 4 on the side close to the exhaust passage is located at the conical angle of the inner edge of the impact platform 603.

[0024] When the total amount of hydrogen injected by the hydrogen injector 1 is small under low load, the hydrogen ejected will first be affected by the flow blocking device 9. However, due to the small total amount of hydrogen and short injection duration, the influence of the flow blocking device 9 on the formation of the fuel mixture is also small. When hydrogen and air enter the cylinder while mixing, a small part of the hydrogen will remain and accumulate around the intake valve 3. However, the presence of the baffle 9 creates a narrow intake gap between the lower intake passage 8 and the hydrogen injector 1. When air passes through, its flow velocity will increase and the pressure will decrease. There will be a pressure difference between the air and the fuel near the intake valve 3, causing the hydrogen accumulated near the intake valve 3 to approach the air at the bottom of the intake passage 8 and be carried into the cylinder. Then the fuel mixture is mixed with the diesel injected by the direct injection fuel injector 4 and is compressed and ignited after forming the fuel mixture.

[0025] Under low load, the total amount of hydrogen required is small, the maximum combustion temperature and exhaust temperature of the in-cylinder mixture are low, and the probability of residual heat sources in the cylinder is small. The air accelerates and flows under the intake gap to form a pressure difference, taking away the hydrogen accumulated above the intake valve 3, preventing the high-temperature exhaust gas from flowing back into the intake passage 8 and igniting the hydrogen accumulated around the intake valve 3 during the valve overlap angle, effectively suppressing backfire.

[0026] Under high load, the total amount of hydrogen injection increases. With the injection pressure remaining unchanged, the injection duration will become longer. When the hydrogen injector 1 injects hydrogen, most of the hydrogen is directly injected into the intake passage 8, and a small part of the hydrogen will hit the intake gap and change its movement direction. The overall hydrogen diffusion angle decreases at a high hydrogen injection flow rate, and it enters the cylinder while mixing with air. Some hydrogen may remain above the intake valve 3. The air accelerates and flows under the intake gap to form a pressure difference, taking away the hydrogen accumulated above the intake valve 3. When the intake valve 3 closes, the high-concentration mixture has completely entered the cylinder, avoiding the accumulation of the fuel mixture near the intake valve 3. Hydrogen and air are preliminarily mixed in the intake passage 8 to form a high-concentration mixture. After entering the cylinder, during the compression stroke, the piston 7 moves upward, and hydrogen further diffuses in the air to form a homogeneous mixture. When the piston 7 moves to the injection moment of the in-cylinder direct injection fuel injector 4, the in-cylinder direct injection fuel injector 4 injects fuel, and the injected diesel is mixed with the fuel mixture to form a fuel mixture. The diesel is compressed and ignited to ignite hydrogen, which pushes the piston 7 to move downward to do work. Then the exhaust stroke begins, the piston 7 moves upward, the exhaust valve 5 opens, and the exhaust gas generated after combustion flows into the exhaust passage and is discharged. However, due to the high hydrogen concentration in the in-cylinder fuel mixture, the maximum combustion temperature and exhaust temperature after the mixture burns will also increase. If the in-cylinder temperature cannot be cooled in time, backfire is very likely to occur. The method for suppressing backfire of an in-cylinder injection hydrogen internal combustion engine under high load will be described below in combination with the combustion chamber design.

[0027] The specific structure of the combustion chamber 6 is as Figure 2 and 3As shown, during the compression stroke, the piston 7 moves upward, and the fuel mixture is pressed into the combustion chamber 6 at the top of the piston 7. The single-layer reentrant combustion chamber design makes the combustion chamber 6 more compact. Reducing its own volume can minimize the retention space of the unburned mixture in the single-layer reentrant combustion chamber and reduce the possibility of its premature ignition. At the same time, it generates strong intake swirl or turbulence to promote the mixing of hydrogen and air. The presence of the impact platform 1003 in the double-layer split combustion chamber makes the piston 7 top surface form a larger opening diameter, which can improve the utilization rate of the in-cylinder space. The upper layer of the double-layer split combustion chamber is shallow dish-shaped, guiding the fuel to the top area of the combustion chamber 6 to promote the utilization of the top clearance volume; the lower layer is the same as the single-layer reentrant combustion chamber design, and vortex clusters that accelerate fuel mixing can be formed inside the combustion chamber 6.

[0028] In this design, when the fuel mixture enters the cylinder from the intake port, it is guided by the wall surface and diffuses towards the center of the cylinder. The fuel mixture will touch the impact platform 603, and the mixture starts to split. The mixture moving upward will promote the formation of a large vortex cluster on the exhaust valve 5 side. The mixture on the lower layer decreases, which will slow down the formation of the vortex cluster on the intake valve 3 side later, reduce the residence time of hydrogen and air on the intake valve 3 side, and prevent the mixture from flowing back into the intake port 8 during the continuous opening of the intake valve 3. Then the large vortex cluster is squeezed and broken by the piston 7 to form small vortex clusters, promoting the mixing of the in-cylinder mixture. When the piston 7 is about to reach the top dead center, the direct injection injector 4 injects diesel. The fuel injection target of the single-layer reentrant combustion chamber is located inside the combustion chamber 6, and the injected fuel spray will mix with the fuel mixture in the pit of the combustion chamber 6 by means of the gas reflux. The fuel injection target of the double-layer split combustion chamber is located on the cone angle of the impact platform, which can achieve rapid stratification of the fuel spray. The fuel mixture in the piston clearance volume mixes with the upper-layer fuel, and the fuel mixture inside the pit of the combustion chamber 6 will mix with the lower-layer fuel. In fact, the double-layer split combustion chamber can be regarded as having two chambers to achieve the diffusion and combustion of double-layer fuel split. This new combustion chamber design promotes the mixing of the fresh fuel mixture in the intake port 8 with the igniting diesel in the combustion chamber 6, speeds up the chemical reaction rate and combustion rate. At the same time, the asymmetric combustion chamber design can reasonably optimize the mixing degree of the fuel mixture in the cylinder. Before the end of the compression stroke, a uniform mixture is formed to avoid too high local mixture concentration. The double-layer split diffusion and combustion of the double-layer split combustion chamber improve the combustion rate and reduce combustion losses. The highest temperature area after combustion is controlled on the exhaust valve 5 side, and there is a longer time to cool the cylinder. During the valve overlap angle, the exhaust gas discharge and the fresh air entering the cylinder will effectively cool the inside of the cylinder. Finally, this asymmetric new combustion chamber design can control the position of the high-temperature area in the cylinder, reduce the temperature in the cylinder, avoid the remaining high-temperature heat source from igniting the fuel mixture entering the cylinder in the next cycle, and suppress the backfire phenomenon of the hydrogen internal combustion engine.

[0029] The baffle device 9 includes a fixing plate 903 fixed to the support plate 10. A connecting plate 902 perpendicular to it is fixed on the fixing plate 903. The other end of the connecting plate 902 is fixed with a baffle 901, and a reinforcing rib plate 904 is fixed on the connecting plate 902.

[0030] The baffle 901 is a rectangular plate, and the upper plate surface of the rectangular plate is parallel to the axial direction of the hydrogen injector 1.

[0031] When the hydrogen injector 1 injects hydrogen, the hydrogen will hit the baffle 901 and change its own movement direction. The longer the vertical length of the baffle 901, the larger the area that hinders the movement of hydrogen. The front and back horizontal lengths mainly affect the gas flow in the intake passage 8. When the vertical length remains unchanged, the longer the horizontal length, the larger the area occupied by the baffle 901 in the cross-section of the intake passage 8. A narrow channel will be formed below the baffle 901. When air flows through here, the speed increases and the pressure decreases, and the surrounding gas will flow towards the low-pressure air. At the top of the intake passage 8, due to the presence of the baffle at the bottom, which hinders the normal flow of a part of the air, the air flow in the upper half of the airway will become stronger and the impact force will increase. When the intake valve 3 is opened, it will effectively reduce the concentration of the fuel mixture accumulated near the intake valve 3. The common length of the intake passage 8 is about 67 mm, and the diameter of the intake passage 8 is about 20 mm. The distance from the bottom nozzle of the hydrogen injector 1 to the top of the intake passage 2 is about 10 mm. The inclination angle of the hydrogen injector 1 is 149°, and the distance from the baffle 901 to the nozzle is about 1 mm. The distance from the bottom of the baffle 901 to the bottom of the intake passage 8 is L. The specific value of L changes with the inclination angle of the hydrogen injector 1 and the distance between the baffle 901 and the hydrogen injector 1. Here, the distance from the baffle 901 to the hydrogen nozzle is about 1 mm, and the size of L is about 3.6 mm.

[0032] Embodiment 3, which is different from Embodiment 2, as Figure 5 shown, the baffle 901 is a trapezoidal plate. The upper plate surface of the trapezoidal plate is parallel to the axial direction of the hydrogen injector 1. The distances from the front and back sides of the trapezoidal plate to the vertical central axis of the trapezoidal plate gradually increase from top to bottom. The area of the trapezoidal plate is related to the model of the hydrogen injector 1. The trajectory of the hydrogen ejected by the hydrogen injector 1 is roughly a cone, and the cross-section is roughly trapezoidal. Therefore, the trapezoidal plate will reduce the area of the original standard rectangular plate according to the number and diameter of the spray holes of the hydrogen injector 1. Compared with the standard rectangular plate, this design will more reasonably guide the movement of hydrogen, optimize the gas movement on both sides of the baffle 901, and strengthen the mixing of the fuel mixture in the intake passage 8. At the same time, the baffle 901 is trapezoidal, and the distances from the front and back sides of the trapezoidal plate to the vertical central axis of the trapezoidal plate gradually increase from top to bottom. After the air flows through the baffle 901 and first separates and then converges, complex gas vortices will be formed, and the movement of the vortices will promote the formation of the mixture. This baffle 901 can reduce the mixing time of hydrogen and air in the intake passage, inhibit backfire by delaying the injection time and extending the in-cylinder cooling time, and is suitable for use in small intake passages.

[0033] Example 4, different from Example 2 or 3, as Figure 6 shown, the baffle 901 is an arc-shaped plate, and the side of the arc-shaped plate close to the connecting plate 902 is a convex curved shape.

[0034] The baffle 901 is changed to an arc-shaped plate, which better fits the hydrogen injection range of the hydrogen injector 1 and effectively guides hydrogen into the cylinder. The arc-shaped plate is suitable for the hydrogen injector 1 with a large aperture. When the hydrogen injection amount is certain, the larger the aperture of the hydrogen injector 1, the shorter the hydrogen injection duration. The negative impact of a large aperture is that a large amount of hydrogen moves towards the intake valve 3, easily forming vortex clusters below the intake valve 3 and on the side of the intake valve 3 close to the exhaust valve 5, hindering the flow of subsequent gases and easily causing hydrogen backflow. When hydrogen is ejected, the hydrogen will move along the baffle 901. At the same time, the short hydrogen injection duration will reduce the mixing time of air and hydrogen in the intake passage 8 and affect the uniformity of the air-fuel mixture. The back of the arc-shaped plate is a convex curved shape. When air flows through the arc-shaped plate, the air will move along the convex surface. Part of the air moves downward along the baffle 901 and converges with the air below. Another part of the air will move along the curve towards both sides of the baffle 901 and finally move upward above the intake passage 8. When the amount of hydrogen in the baffle 901 is excessive, the hydrogen at the boundary of the baffle 901 is affected by the air flow direction and moves upward above the intake passage 8. Air and hydrogen in multiple directions will form a vortex cluster above the intake passage 8, promoting the formation of the air-fuel mixture in the intake passage 8 and alleviating the intake blockage near the intake valve 3. In summary, the arc-shaped plate paired with the hydrogen injector 1 with a large aperture can delay the injection moment of the hydrogen injector and shorten the hydrogen injection duration. On the one hand, it prolongs the cooling time of the cylinder and reduces the possibility of the high-temperature heat source igniting the fuel mixture. On the other hand, it alleviates the disadvantages brought by the hydrogen injector 1 with a large aperture, relieves the intake blockage, reduces the concentration of hydrogen accumulation above the intake valve 3, and prevents the high-temperature exhaust gas from flowing back into the intake passage 8 in the next cycle and igniting the accumulated mixture.

[0035] Example 5, based on Examples 2 to 4, as Figure 7 shown, the middle part of the connecting plate 902 and the baffle 901 is hinged, and a first tension spring 905 is fixed to the back side of the upper end of the baffle 901, and the other end of the first tension spring 905 is fixed to the fixing plate 903.

[0036] Under normal conditions, the baffle 901 has a certain angle with the axis of the hydrogen injector 1. When the injection flow rate increases, the pressure under the baffle 901 increases, and the baffle 901 will gradually rotate clockwise. When it is parallel to the axis of the hydrogen injector 1, it reaches the maximum value. Compared with the standard baffle 901, this baffle 901 realizes the adjustment of the angle, and uses the hydrogen pressure ejected by the hydrogen injector 1, which is a simple mechanical structure. When the hydrogen internal combustion engine is at a small load, the injection pressure of the hydrogen injector 1 is not sufficient to rotate the baffle 901. And under the small load condition, the ejected hydrogen is less affected by the baffle 901. The baffle 901 is in an inclined state compared with the axis of the hydrogen injector 1. Compared with the standard baffle, the inclined baffle 901 is more conducive to the intake of the intake passage 8 under small loads, making the gas movement in the upper and lower parts of the intake passage 8 more reasonable. Moreover, due to the inclination of the baffle 901, the air above the intake passage 8 can move along the direction of the baffle 901, optimizing the hydrogen flow in the intake passage 8 and improving the mixture uniformity. And before the hydrogen injection moment, during the valve overlap angle, the high-temperature exhaust gas is likely to flow back from the cylinder into the intake passage 8. The inclination of the baffle 901 can cause the air moving along the direction of the baffle 901 and the air at the bottom of the intake passage 8 to squeeze and generate a swirl near the intake valve 3, hindering the reverse flow of the exhaust gas into the intake passage 8 and reducing the harm caused by the backfire of the high-temperature exhaust gas flowing back into the intake passage 8 under small loads. As the piston 7 gradually moves downward during the intake stroke, the cylinder pressure decreases, and the swirl near the intake valve 3 breaks, accelerating the entry of the air in the intake passage 8. Under large load conditions, the position of the baffle 901 during the hydrogen injection duration is the same as that of the standard baffle 901, but after the hydrogen injection ends, the baffle 901 will return to the inclined position again, and the inclined baffle 901 will be more conducive to the air flow in the intake passage 8.

[0037] Embodiment 6, different from Embodiment 2, as Figure 8 shown, the baffle device 9 includes a square support shaft parallel to the axis of the hydrogen injector 1. A first iron core 906 that can slide up and down along the axis is sleeved on the support shaft. A connecting sleeve 910 is fixed on the side of the first iron core 906 away from the support plate 10. A baffle is connected to one end of the connecting sleeve 910 away from the support plate 10. Springs 909 are sleeved on the support shaft above and below the first iron core 906. Support blocks 907 are fixed at both ends of the support shaft, and the support blocks 907 are fixed on the support plate 10. Electromagnets 908 symmetric about the support axis are provided on the opposite sides of the upper and lower support blocks 907.

[0038] An electromagnet two 919 is fixedly installed inside the connecting sleeve 910. Outside the electromagnet two 919, there is an iron core two 918 that can slide inside the connecting sleeve 910. The outer end of the iron core two 918 is fixedly connected with a control rod 917. The outer end of the control rod 917 passes through the outer end of the connecting sleeve 910 and is symmetrically hinged with a connecting rod 915. The baffle includes an outer baffle 916 hinged at the other end of the connecting rod 915. Sliding cavities are provided on the opposite sides of the two outer baffles 916. Inside the sliding cavities, there are sliders 912. An inner baffle 913 is fixedly connected between the two sliders 912. A fixing rod 914 is fixedly installed on the outer side wall of the connecting sleeve 910. The other end of the fixing rod 914 is fixedly connected with the inner baffle 913. The outer end of the iron core two 918 is fixedly connected with a tension spring two 911. The other end of the tension spring two 911 is fixedly connected with the inner wall of the outer end of the connecting sleeve 910.

[0039] When the electromagnet one 908 is energized, different energizations of the electromagnet one 908 can achieve the up and down movement of the baffle. Different currents can achieve multiple position adjustments. When the electromagnet one 908 is de-energized, the spring 909 can control the iron core one 906 to return to the initial position, that is, the baffle also returns to the original position. When the electromagnet two 919 is energized, the control rod 917 moves to the left, driving the connecting rod 915 to move, causing the outer baffle 916 to move towards the middle, and the overall area of the baffle decreases. When the electromagnet two 919 is de-energized, the tension spring two 911 pulls the iron core two 918 to move to the right, the control rod 917 is pushed out, and the outer baffle 916 expands towards both sides, increasing the overall area of the baffle.

[0040] Under the small load condition, the baffle has little influence on the ejected hydrogen, but has a greater influence on the air flow in the intake passage 8. If there is exhaust gas flowing back into the intake passage 8 at this time, before the hydrogen injector 1 injects hydrogen, the lower electromagnet one 908 is energized, causing the baffle to move downward. At this time, the baffle will extend below the horizontal height of the bottom corner of the intake passage 8. When the air flows through here, the reduction of the channel diameter and the change of the flow direction will make the air flowing into the intake valve from the bottom of the intake passage 8 easier to form vortex clusters near the intake valve 3. The air in the intake passage 8 and the exhaust gas flowing back into the cylinder will decelerate around the vortex clusters, forming more complex vortex clusters. These vortex clusters will hinder the movement of the air flow on both sides. However, as the exhaust valve 5 continues to open and the piston moves downward during the intake stroke, the pressure in the cylinder gradually decreases, and the exhaust gas is discharged from the exhaust valve 5. At this time, the vortex clusters at the intake valve 3 break, and the lower electromagnet one 908 is de-energized. The baffle returns to the original position by the elastic force of the spring 909. The electromagnet two 919 is energized, and the outer baffle 916 moves inward, reducing the baffle area to facilitate the air to flow into the cylinder. The hydrogen injector 1, the direct injection fuel injector 4, the intake valve 3, and the exhaust valve 5 are connected to the vehicle-mounted computer 2. The vehicle-mounted computer 2 is connected to the pressure sensor in the cylinder. The vehicle-mounted computer 2 is also connected to the upper and lower electromagnets one 908 and controls the energization and de-energization respectively; the vehicle-mounted computer 2 is also connected to the electromagnet two 919 and controls the energization and de-energization.

[0041] Under high load conditions, the residual high-temperature heat source in the cylinder is the key to causing the backfire problem. The simplest way to reduce the temperature in the cylinder is to extend the cooling time of the in-cylinder gas. By increasing the injection pressure of the hydrogen injector 1 and shortening the injection duration, the in-cylinder cooling time can be extended. However, shortening the injection duration will cause a large amount of hydrogen to enter the intake valve 3 simultaneously, which is likely to cause intake blockage. After hydrogen enters the cylinder, a pair of vortex groups with opposite directions are formed under the valve seat of the intake valve, making the hydrogen in the cylinder prone to backflow. At the same time, late injection will also result in a shorter mixing time of hydrogen and air in the cylinder, causing the in-cylinder air-fuel mixture to be uneven. Therefore, the above problems can be solved by changing the position of the baffle through the vehicle-mounted computer 2. When the hydrogen injector 1 is at the injection moment, the lower electromagnet 908 is energized, causing the baffle to move downward. The injected hydrogen is guided by the baffle and enters the cylinder to mix with the air in the cylinder. Since the baffle moves downward, the height above the baffle will be lower than the nozzle of the hydrogen injector 1, and a small part of the injected hydrogen will impact on the top of the baffle and move in the direction of the air flow. When this small part of hydrogen encounters air, it will mix with the air in the intake passage 8 and retard the movement speed of the air. The air at the bottom of the intake passage 8 flows through the lower part of the baffle, its movement direction changes, the flow size first decreases and then increases, and it converges with the hydrogen flowing along the baffle, and most of it enters the cylinder from the left side of the intake valve 3. Compared with the case without a baffle, during the hydrogen injection period, the air flow rate into the cylinder decreases, and the air is reasonably diverted. The air-fuel mixture flow rate on the right side of the intake valve 3 decreases, and the vortex size decreases. On the left side of the intake valve 3, the baffle guides the air, increasing the air flow intensity, and the vortex originally formed at the bottom of the intake valve 3 will move downward, promoting the formation of the in-cylinder air-fuel mixture.

[0042] In addition, it should be understood that although this specification is described according to the embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0043] In the description of the present invention, the orientation or positional relationship indicated by the terms "inner", "outer", "longitudinal", "transverse", "upper", "lower", "top", "bottom", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention rather than requiring the present invention to be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention.

Claims

1. A device for suppressing flashback of an intake duct hydrogen injection compression ignition internal combustion engine, comprising a cylinder block, a piston (7), an intake duct (8), an exhaust duct, an intake valve (3), an exhaust valve (5), and a direct injection injector (4), wherein a combustion chamber (6) is provided on the top of the piston (7), and wherein: The combustion chamber (6) is ω-shaped. The combustion chamber (6) is divided into a single-layer reflow combustion chamber and a double-layer split-flow combustion chamber from the middle. The single-layer reflow combustion chamber and the double-layer split-flow combustion chamber are respectively close to one side of the intake passage (8) and one side of the exhaust passage. A semicircular arc-shaped impact platform (603) is provided on the outer side of the top of the double-layer split-flow combustion chamber. A smooth transition arc surface (604) is provided between the outer wall of the impact platform (603) and the top of the piston (7). A hydrogen injector (1) is provided in an inclined manner in the intake passage (8) and is directed toward the intake valve (3). A flow blocking device (9) is provided below the nozzle of the hydrogen injector (1). A support plate (10) parallel to the axis of the hydrogen injector (1) is fixed below the hydrogen injector (1). The flow blocking device (9) is fixed at the lower end of the support plate (10). An intake gap is provided between the bottom of the flow blocking device (9) and the bottom of the intake passage (8).

2. The device for suppressing flashback of a compression ignition internal combustion engine with hydrogen injection in the intake port according to claim 1, characterized in that: The bottom of the combustion chamber (6) is a conical guide platform (601), and an upwardly tilted arc-shaped combustion chamber recess (602) is provided on the outer side of the conical guide platform (601). A second smooth transition arc surface (605) is provided between the top of the combustion chamber recess (602) in the single-layer reflow combustion chamber (6) and the top of the piston (7).

3. The device for suppressing flashback of a compression ignition internal combustion engine with hydrogen injection in the intake port according to claim 2, characterized in that: The fuel injection of the direct injection injector (4) on the side close to the intake passage (8) is a conical injection toward the single-layer reflow combustion chamber (6), and the fuel injection target of the direct injection injector (4) on the side close to the exhaust passage is located at the cone angle of the inner end edge of the impact platform (603).

4. The device for suppressing flashback of a compression ignition internal combustion engine with hydrogen injection in the intake port according to claim 1, characterized in that: The flow blocking device (9) comprises a fixing plate (903) fixed to the support plate (10), a connecting plate (902) perpendicular thereto being fixed on the fixing plate (903), a baffle (901) being fixed to the other end of the connecting plate (902), and a reinforcing rib plate (904) being fixed on the connecting plate (902).

5. The device for suppressing flashback of a compression ignition internal combustion engine with hydrogen injection in the intake port according to claim 4, characterized in that: The baffle (901) is a rectangular plate, and the upper plate surface of the rectangular plate is parallel to the axial direction of the hydrogen injector (1).

6. The device for suppressing flashback of a compression ignition internal combustion engine with hydrogen injection in the intake port according to claim 4, characterized in that: The baffle plate (901) is a trapezoidal plate, the upper plate surface of the trapezoidal plate is parallel to the axial direction of the hydrogen injector (1), and the distances from the front and rear sides of the trapezoidal plate to the vertical center axis of the trapezoidal plate gradually increase from top to bottom.

7. The device for suppressing flashback of a compression ignition internal combustion engine with hydrogen injection in the intake port according to claim 4, characterized in that: The baffle plate (901) is an arc-shaped plate, and the side of the arc-shaped plate close to the connecting plate (902) is a convex curve.

8. A device for suppressing flashback of a compression ignition internal combustion engine with hydrogen injection in the intake port according to any one of claims 5 to 7, characterized in that: The middle part of the connecting plate (902) and the baffle plate (901) is hinged, a tension spring 1 (905) is fixed to the back side of the upper end of the baffle plate (901), and the other end of the tension spring 1 (905) is fixed to the fixing plate (903).

9. The device for suppressing flashback of a compression ignition internal combustion engine with hydrogen injection in the intake port according to claim 1, characterized in that: The baffle device (9) comprises a support shaft parallel to the axial direction of the hydrogen injector (1); an iron core (906) is sleeved on the support shaft and can slide up and down along the axial direction; a connecting sleeve (910) is fixed on the side of the iron core (906) away from the support plate (10); the end of the connecting sleeve (910) away from the support plate (10) is connected to the baffle plate; springs (909) are sleeved on the upper and lower support shafts of the iron core (906); support blocks (907) are fixed at both ends of the support shaft; the support blocks (907) are fixed on the support plate (10); and the upper and lower support blocks (907) are both provided with electromagnets (908) symmetrical about the support shaft.

10. The device for suppressing flashback of a compression ignition internal combustion engine with hydrogen injection in the intake port according to claim 9, characterized in that: A second electromagnet (919) is fixed in the connecting sleeve (910), and an iron core (918) that can slide in the connecting sleeve (910) is provided on the outer side of the second electromagnet (919). A control rod (917) is fixed to the outer end of the second iron core (918). The outer end of the control rod (917) passes through the outer end of the connecting sleeve (910) and is symmetrically hinged to a connecting rod (915). The baffle plate includes an outer baffle plate (916) hinged to the other end of the connecting rod (915). The two outer baffle plates (916) are 16) are provided with sliding cavities on opposite sides, a sliding block (912) is provided in the sliding cavity, an inner baffle plate (913) is fixedly connected between the two sliding blocks (912), a fixing rod (914) is fixed on the outer side wall of the connecting sleeve (910), the other end of the fixing rod (914) is fixed to the inner baffle plate (913), the outer end of the second iron core (918) is fixed with a second tension spring (911), the other end of the second tension spring (911) is fixed to the inner wall of the outer end of the connecting sleeve (910).

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