A structure and method for improving the sealing performance of a hydrogen injector

Abstract

The present invention discloses a structure and method for improving the sealing performance of a hydrogen injector, belonging to the field of engine technology, comprising an outer shell of an electromagnetic valve, an electromagnetic valve body arranged in the outer shell of the electromagnetic valve, and an integrated coil wound around the outer periphery of the outer shell of the electromagnetic valve; the electromagnetic valve body comprises a needle valve, a moving iron core, a spring and a static iron core, the centers of the moving iron core and the static iron core are both provided with a hollow area, the static iron core is arranged in the upper area of ​​the electromagnetic valve body, the moving iron core is arranged in the lower area of ​​the electromagnetic valve body, the spring is arranged in the hollow area of ​​the static iron core, and the needle valve passes through the hollow area of ​​the moving iron core and is connected to the spring; and the structure and method comprise four stages: a needle valve opening stage, a needle valve continuously opening stage, a needle valve seating and closing stage, a needle valve already seated, a late compression stroke stage and an early power stroke stage; the structure and method provided by the present invention effectively improve the sealing characteristics of the existing hydrogen nozzle, and improve the reliability and service life of the hydrogen nozzle.

Description

Technical Field

[0001] The present invention belongs to the technical field of engines, and in particular relates to a structure and method for improving the sealing performance of a hydrogen injector. Background Art

[0002] Hydrogen energy, a form of energy that utilizes hydrogen as a medium, offers advantages such as widespread availability, low emissions, and high energy density. It is a key tool for achieving my country's dual carbon goals and will help build a cleaner and more sustainable energy system in China. Currently, mainstream hydrogen powertrains include hydrogen fuel cells and hydrogen internal combustion engines. Hydrogen internal combustion engines offer advantages such as low cost for industrial upgrading and environmental friendliness, and have significant advantages in heavy-duty commercial vehicles, ships, and other applications.

[0003] Key factors in hydrogen internal combustion engine development include optimizing fuel mixing and combustion in the cylinder, suppressing abnormal combustion in the cylinder, exhaust gas control, material reliability, durability, and system safety. The quality of the engine's in-cylinder combustion and emissions performance is closely linked to the hydrogen injection system. As a core component of the hydrogen injection system, the performance of the hydrogen injector is particularly crucial. The design of the nozzle must consider the unique physical and chemical properties of hydrogen to ensure precise injection, efficient combustion, and stable injection under high-temperature and high-pressure environments. The increase in hydrogen internal combustion engine power is limited by the flow rate of the hydrogen injector. However, gas flow is not only limited by the cross-sectional area and flow coefficient at the nozzle outlet, but also by the gas pressure and density at the supply end. Under high-pressure injection conditions, the small size and rapid diffusion of hydrogen molecules pose new challenges to the sealing of the hydrogen injector. Chinese patent application number CN117514532A discloses a control method for a hydrogen injector. This method, described using a direct-injection gas nozzle as an example, involves controlling the current entering the control valve coil to segmentally control the operating state of the control valve and valve core assembly, thereby achieving rapid hydrogen injector opening and mitigating internal collisions, thereby improving the reliability of the hydrogen injector. However, the collision requirements between the control valve and valve core assembly used to determine the current parameters in this method are difficult to obtain, and in actual applications, the external pressure requirements on the sealing surface at the lower end of the valve core assembly are non-negligible. Summary of the Invention

[0004] The purpose of the present invention is to provide a structure and method for improving the sealing performance of a hydrogen injector, so as to solve the problem that the sealing characteristics of the existing electromagnetically driven hydrogen nozzle are related to the nozzle structure and material properties, and are mainly achieved by the contact pressure between the needle valve pair, but the external pressure changes to which the needle valve is subjected during actual operation of the nozzle cannot be ignored. Specifically, for an inward-opening nozzle, excessive in-cylinder pressure will cause the needle valve to push upward, resulting in a temporary failure of the hydrogen injector seal, causing hydrogen leakage, and even the risk of high-temperature water vapor after combustion flowing back into the nozzle; for an outward-opening nozzle, excessive in-cylinder pressure will cause wear or deformation in the stress concentration area of ​​the needle valve sealing surface. If the cylinder pressure change is not taken into account, it is also easy to cause the nozzle seal to fail.

[0005] To achieve the above-mentioned objectives, the present invention provides a structure for improving the sealing performance of a hydrogen injector, comprising an outer shell of a solenoid valve, a solenoid valve body arranged in the outer shell of the solenoid valve, and an integrated coil wound around the periphery of the outer shell of the solenoid valve; the solenoid valve body comprises a needle valve, a moving iron core, a spring, and a static iron core, and a hollow area is provided in the center of the moving iron core and the static iron core, the static iron core is provided in the upper area of ​​the solenoid valve body, the moving iron core is provided in the lower area of ​​the solenoid valve body, the spring is provided in the hollow area of ​​the static iron core, and the needle valve passes through the hollow area of ​​the moving iron core and is connected to the spring.

[0006] Preferably, a gap is provided between the moving iron core and the static iron core, and the winding of the integrated coil is disconnected at the gap between the moving iron core and the static iron core to form nodes b and c, at which nodes b and c are provided with on-off control.

[0007] Preferably, the on-off control provided at nodes b and c is a diode element or a hydrogen injection signal, specifically, nodes b and c are closed during the hydrogen injection period, and are disconnected during the remaining time.

[0008] The present invention also provides a method for improving the sealing performance of a hydrogen injector, which includes four stages: a needle valve opening stage, a needle valve continuously opening stage, a needle valve seated closing stage, a needle valve seated stage, a late compression stroke stage, and an early power stroke stage.

[0009] Preferably, a larger electromagnetic force is required during the needle valve opening stage to quickly lift the needle valve and open the gas delivery channel. By controlling the potential of the coil nodes a and d, a DC current is input, and the b and c nodes are turned on. The entire structure has the maximum upward electromagnetic force (negative y direction); the nodes a and d are the two ends of the integrated coil.

[0010] Preferably, during the continuous opening stage of the needle valve, the elastic force of the spring increases and remains stable for a period of time. At this time, the cylinder pressure increases due to the compression stroke in the cylinder, and the upward force on the needle valve increases. The power supply current of the coil in the lower area is adjusted downward in a step-by-step manner according to the cylinder pressure signal data, and the electromagnetic force is reduced to keep the force on the needle valve near the preset point. This can save energy and reduce the contact stress between the moving iron core and the upper part of the needle valve and its contact surface.

[0011] Preferably, the electromagnetic force is reduced by reducing the current or controlling the node potential so that only segments a and b are energized.

[0012] Preferably, during the needle valve seating and closing stage, the pressure in the cylinder is at a high level, and the current is slowly reduced according to the cylinder pressure signal curve and the elastic force curve of the spring to reduce the impact when the needle valve is seated.

[0013] Preferably, when the needle valve is seated, in the late compression stroke and early power stroke stages, a forward current is passed between nodes a and b of the solenoid valve coil, and a reverse current is passed between nodes c and d. The current size is matched according to the cylinder pressure signal, so that the needle valve is subjected to a stable downward force that meets the sealing requirements.

[0014] Therefore, the present invention adopts the above-mentioned structure and method for improving the sealing performance of the hydrogen injector, which has the following beneficial effects:

[0015] (1) The coils are wound uniformly on a bobbin, wherein the separation nodes are connected through diodes or other internal circuits. By controlling the current between the nodes during the needle valve seating and closing period, a reverse electromagnetic force can be achieved to increase the contact pressure of the needle valve sealing surface, thereby improving the sealing performance of the hydrogen injector;

[0016] (2) By using an integrated coil winding solenoid valve structure, the actual force of the needle valve is taken into consideration during the opening of the needle valve, and the spring force curve, cylinder pressure curve, etc. are taken into account. By reasonably adjusting the electromagnetic force, the internal collision of the needle valve is reduced and the reliability of the hydrogen injector is improved.

[0017] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a cross-sectional view of a structure for improving the sealing performance of a hydrogen injector according to the present invention;

[0019] Figure 2 This is a control flow chart of a method for improving the sealing performance of a hydrogen injector according to the present invention;

[0020] Figure 3 This is the on-off control principle diagram of the present invention;

[0021] Figure 4Schematic diagram of the electromagnetic force variation trend in an embodiment of the present invention;

[0022] Among them, 1. needle valve; 2. moving iron core; 3. integrated coil; 4. spring; 5. static iron core; 6. external shell of solenoid valve. DETAILED DESCRIPTION

[0023] The following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort shall fall within the scope of protection of the present invention.

[0024] See also Figure 1-4 A structure for improving the sealing performance of a hydrogen injector includes a solenoid valve outer housing 6, a solenoid valve body disposed within the solenoid valve outer housing 6, and an integrated coil 3 wound around the outer periphery of the solenoid valve outer housing. The solenoid valve body includes a needle valve 1, a movable iron core 2, a spring 4, and a stationary iron core 5. Both the movable iron core 2 and the stationary iron core 5 have hollow regions in their centers. The stationary iron core 5 is disposed in the upper region of the solenoid valve body, while the movable iron core 2 is disposed in the lower region of the solenoid valve body. The spring is disposed in the hollow region of the stationary iron core 5. The needle valve 1 passes through the hollow region of the movable iron core 2 and connects to the spring 4. A gap is provided between the movable iron core 2 and the stationary iron core 5. The integrated coil 3 is disconnected at the gap between the movable iron core 2 and the stationary iron core 5, forming nodes b and c. On-off control is provided at nodes b and c. The on-off control provided at nodes b and c is a diode element or a hydrogen injection signal. Specifically, nodes b and c are closed during hydrogen injection and open during the rest of the time.

[0025] A method for improving the sealing performance of a hydrogen injector includes four stages: a needle valve opening stage, a needle valve continuously opening stage, a needle valve seated closing stage, a needle valve seated stage, a late compression stroke stage, and an early power stroke stage. Figure 4 As shown, the crankshaft angle is -130°CA~70°CA, which includes the main stages described in the present invention, wherein the hydrogen injection phase is -130°CA~-70°CA, and the ignition angle is -3°CA, which are specifically described as follows:

[0026] During the needle valve opening stage, a large electromagnetic force is required to quickly lift the needle valve and open the gas delivery channel. By controlling the potential of the coil nodes a and d, a DC current I1 is input, and the b and c nodes are turned on. The entire structure has the maximum upward electromagnetic force (negative y direction); the nodes a and d are the two ends of the integrated coil.

[0027] During the needle valve's sustained opening phase, the spring force increases and remains stable for a period. The cylinder pressure rises during the compression stroke, increasing the upward force on the needle valve. Based on the cylinder pressure signal, a ramp-down current is input to the coil, I2, reducing the electromagnetic force and keeping the needle valve force near the preset point. This saves energy and reduces the contact stress between the moving iron core and the upper portion of the needle valve. Reducing the electromagnetic force involves lowering the current or controlling the node potential so that only segments a and b are energized.

[0028] During the needle valve seating and closing stage, the pressure in the cylinder gradually increases, and the current is slowly reduced to I3=0 according to the matching of the cylinder pressure signal curve and the elastic force curve of the spring, thereby reducing the impact when the needle valve is seated.

[0029] When the needle valve is seated, in the late compression stroke and early power stroke, a forward current I4 flows between nodes a and b of the control solenoid valve coil, and a reverse current -I4 flows between nodes c and d. The current magnitude is matched to the cylinder pressure signal, resulting in a stable downward force on the needle valve that meets sealing requirements. During this stage, the cylinder pressure's effect on the needle valve becomes significant. When the downward spring and gas forces acting on the needle valve are insufficient to withstand the explosive pressure within the cylinder, a forward current flows through nodes a and b, and a reverse current flows through nodes c and d, generating a downward reverse electromagnetic force (in the positive y direction) to improve sealing. The current magnitude is matched to the cylinder pressure signal to ensure that the resultant force on the needle valve is stable and meets sealing requirements. Furthermore, because the winding length between nodes d and c is shorter than that of segment ab, when a constant current is applied, the potential at node c is higher than that at node b, preventing current from flowing through the diode and affecting the current at nodes ab. As the cylinder pressure decreases, the current in the control coil drops to I5 = 0.

[0030] Therefore, the present invention adopts the above-mentioned structure and method for improving the sealing performance of the hydrogen injector, combined with the actual force conditions of the nozzle needle valve, not only by controlling the magnitude of the electromagnetic force by controlling the current, but also by controlling the current direction between the two coils to apply a reverse electromagnetic force, thereby improving the sealing performance at the sealing surface of the needle valve head.

[0031] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solutions of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A structure for improving the sealing performance of a hydrogen injector, characterized in that: The invention comprises an outer shell of a solenoid valve, a solenoid valve body arranged in the outer shell of the solenoid valve, and an integrated coil wound around the outer periphery of the outer shell of the solenoid valve; the solenoid valve body comprises a needle valve, a movable iron core, a spring, and a static iron core, wherein the centers of the movable iron core and the static iron core are both provided with a hollow area, the static iron core is arranged in the upper area of ​​the solenoid valve body, the movable iron core is arranged in the lower area of ​​the solenoid valve body, the spring is arranged in the hollow area of ​​the static iron core, and the needle valve passes through the hollow area of ​​the movable iron core and is connected to the spring; A gap is provided between the moving iron core and the static iron core, and the winding of the integrated coil is disconnected at the gap between the moving iron core and the static iron core to form nodes b and c, and on-off control is provided at the nodes b and c; The method for improving the sealing performance of the hydrogen injector structure includes four stages: the needle valve opening stage, the needle valve continuously opening stage, the needle valve seated closing stage, the needle valve seated stage, the late compression stroke stage, and the early power stroke stage. During the needle valve opening phase, a large electromagnetic force is required to quickly lift the needle valve and open the gas delivery channel. By controlling the potential of the coil nodes a and d, a DC current is input, which then conducts the nodes b and c. Nodes a and d are the two ends of the integrated coil. When the needle valve is seated, in the late compression stroke and early power stroke stages, a forward current is passed between nodes a and b of the solenoid valve coil, and a reverse current is passed between nodes c and d. The current size is matched according to the cylinder pressure signal, so that the needle valve is subjected to a stable downward force that meets the sealing requirements.

2. The structure for improving the sealing performance of a hydrogen injector according to claim 1, characterized in that: The on-off control set at nodes b and c is a diode element or a hydrogen injection signal. Specifically, nodes b and c are closed during the hydrogen injection period, and are disconnected during the remaining time.

3. The structure for improving the sealing performance of a hydrogen injector according to claim 1, characterized in that: During the continuous opening stage of the needle valve, the elastic force of the spring increases and remains stable for a period of time. At this time, the cylinder pressure increases due to the compression stroke in the cylinder, and the upward force on the needle valve increases. According to the cylinder pressure signal data, the power supply current of the coil in the lower area is adjusted downward in a step-by-step manner to reduce the electromagnetic force so that the force on the needle valve remains near the preset point.

4. The structure for improving the sealing performance of a hydrogen injector according to claim 3, characterized in that: The electromagnetic force can be reduced by reducing the current or controlling the node potential so that only segments a and b are energized.

5. The structure for improving the sealing performance of a hydrogen injector according to claim 1, characterized in that: During the needle valve seating and closing stage, the pressure in the cylinder is at a high level. The current is slowly reduced according to the cylinder pressure signal curve and the elastic force curve of the spring to reduce the impact when the needle valve is seated.

Images