Double-peak holding driving waveform control method for electromagnetic ammonia-hydrogen gas fuel injector

Abstract

The invention relates to a double-peak maintaining driving waveform control method for an electromagnetic ammonia-hydrogen gas fuel injector, which comprises the following steps of: (a) applying a high voltage to an injector coil, so that the coil current rapidly rises to a first peak current value Ip1 within an extremely short time, and maintaining for a short time Tp1; (b) adjusting and reducing the coil current to a second peak current value Ip2 and maintaining the second peak current value Ip2 for a period of time Tp2; and (c) reducing the current of the coil to a holding current value Ih, and maintaining the current in the whole residual injection pulse width time Th. And the movement of the armature is actively decelerated in the second peak stage, so that the armature can stably and controllably reach the full-open position, the mechanical impact is greatly reduced, the high consistency of the lift of the valve core and the full-open position in each injection is ensured, and the metering accuracy of the gas fuel is improved.

Description

Technical Field

[0001] This invention belongs to the field of internal combustion engine fuel injection control technology, and relates to a drive waveform control method, specifically a dual-peak holding drive waveform control method for an electromagnetic ammonia-hydrogen gas fuel injector. Background Technology

[0002] Gaseous fuels, such as hydrogen, ammonia, and natural gas, are increasingly used in internal combustion engines (especially in the power systems of medium and heavy-duty commercial vehicles, ships, and construction machinery). The performance and lifespan of a gas-fueled engine largely depend on the reliability and precision of its core component (the gas fuel injector).

[0003] Electromagnetic ammonia-hydrogen gas fuel injectors typically include components such as an electromagnetic coil, an iron core, an armature (or linked with a valve core / plunger), and a valve seat. Their working principle is as follows: when the ECU applies a drive current to the coil, the generated electromagnetic force attracts the armature to move against the spring preload, causing the valve core to disengage from the valve seat, thereby opening the fuel passage; after the current is cut off, the electromagnetic force disappears, and the armature and valve core reset under the action of the spring, closing the passage.

[0004] Compared to traditional liquid fuel injectors, gas fuel injectors face a significant challenge in drive control: the gas medium provides virtually no effective hydraulic damping. In liquid injectors, the viscosity of the fuel can cushion the impact of moving parts (armature, valve core) at the end of their stroke; however, in gas injectors, the moving parts, driven by electromagnetic force, will impact the limiting structure (such as the iron core or mechanical limiter) with high kinetic energy, or impact the valve seat at high speed when closing. This undamped "hard-on-hard" impact leads to severe mechanical wear, noise, and ultimately affects the injector's service life and sealing reliability.

[0005] To address this challenge, existing technologies are mainly improved through two paths: (1) Mechanical structure improvement path: This path focuses on physically buffering the impact by optimizing the hardware design. The main methods are: ① Setting physical gaps: For example, as disclosed in Chinese invention patent CN116753088A: through precise mechanical design, it is ensured that when the armature moves to the limit position (preset position), it still maintains a small "preset gap" with the iron core, thereby completely avoiding direct collision between the two and transferring the impact energy to other more impact-resistant limiting components. Although this method is effective, it increases the complexity of mechanical design and the requirements for processing precision, and does not eliminate the impact, but only transfers the impact point. ② Introducing buffer materials or damping devices: Some technologies use elastic materials such as rubber or independent hydraulic damping chambers to absorb impact energy. However, these materials may have poor high-temperature resistance and are prone to aging and failure, while the additional damping devices will increase the complexity and cost of the system and may bring sealing problems.

[0006] (2) Drive control optimization path: This path focuses on managing the kinetic energy of moving parts from the source by optimizing the electronic control strategy. The classic Peak-and-Hold drive is currently the most mainstream drive method. Its drive current waveform includes an initial high peak current (Peak) stage and a subsequent lower holding current (Hold) stage. The high peak current is used to quickly generate a sufficiently large electromagnetic force to overcome static friction and spring force, so that the armature can start quickly; then the current drops to a lower holding current to just maintain the valve port fully open until the injection ends. The traditional single-peak-hold waveform has relatively coarse control over the motion process. Its peak current is usually applied with fixed parameters to quickly complete the opening, but the speed of the armature when it is close to the fully open position is not finely controlled. This results in the armature and linkage components still impacting the limiting structure with high residual kinetic energy in the environment where the gas fuel lacks damping, causing impact and wear. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a dual-peak holding drive waveform control method for electromagnetic ammonia-hydrogen gas fuel injectors.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is: a dual-peak holding drive waveform control method for an electromagnetic ammonia-hydrogen gas fuel injector, comprising the following steps: (a) Apply a high voltage to the injector coil, causing the coil current to rise rapidly to the first peak current value Ip1 in a very short time and maintain it for a short time Tp1; (b) Reduce the coil current to the second peak current value Ip2 and maintain it for a period of time Tp2; (c) The coil current is then reduced to the holding current value Ih and maintained for the entire remaining injection pulse width time Th.

[0009] Ideally, in step (a), at the start of the injection command, a high voltage is applied to the injector coil using the ECU control drive circuit.

[0010] Further, in step (a), the extremely short time is 0.1-1ms, preferably 0.1-0.5ms; the short time Tp1 is 0.3-1.0ms.

[0011] Ideally, in step (a), the first peak current value Ip1 is 80%-150% of the rated current.

[0012] Ideally, in step (b), the second peak current value Ip2 is greater than the holding current value Ih and the second peak current value Ip2 is less than the first peak current value Ip1.

[0013] Furthermore, in step (b), the time period Tp2 is 0.2-0.8 ms.

[0014] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art: The dual-peak holding drive waveform control method of the present invention for electromagnetic ammonia-hydrogen gas fuel injectors, without changing the mechanical structure of the injector body, achieves precise current regulation in three stages within a single drive cycle (i.e., injection pulse width time Th) entirely through the innovation of electronic control software. Thus, the armature movement is "actively decelerated" through the second peak (Peak2) stage, achieving a smooth and controlled arrival at the fully open position, greatly reducing mechanical shock, ensuring the consistency of valve core lift and fully open position in each injection, thereby improving the accuracy of gas fuel metering. Attached Figure Description

[0015] Figure 1 This is a block diagram of the overall architecture of the dual-peak holding drive waveform control system for an electromagnetic ammonia-hydrogen gas fuel injector according to the present invention. Figure 2 This is a schematic diagram of the dual-peak holding drive waveform control method for an electromagnetic ammonia-hydrogen gas fuel injector according to the present invention. Detailed Implementation

[0016] The present invention will be further described below with reference to the embodiments shown in the accompanying drawings.

[0017] This invention relates to a dual-peak holding drive waveform control method for electromagnetic ammonia-hydrogen gas fuel injectors, based on Figure 1 The diagram shows a dual-peak holding drive waveform control system for an electromagnetic ammonia-hydrogen gas fuel injector. The control system includes: (1) an electromagnetic ammonia-hydrogen gas fuel injector: including standard components such as an electromagnetic coil, a movable armature (or a linkage valve core), a fixed iron core, a return spring, and a valve seat; (2) an engine control unit (ECU): including a microprocessor, a memory, and a drive circuit; the memory contains a pre-stored control parameter mapping table related to this drive waveform; the drive circuit is usually an H-bridge or a similar topology, used to receive instructions from the ECU microprocessor and apply precise voltage / current to the injector coil; (3) connection relationship: the output terminal of the ECU drive circuit is connected to the electrical terminal of the gas fuel injector electromagnetic coil, and the ECU calls the corresponding drive waveform parameters to control the injector action through the drive circuit.

[0018] The dual-peak holding drive waveform control method for electromagnetic ammonia-hydrogen gas fuel injectors includes the following steps: (a) First peak current stage (Peak1): A high voltage is applied to the injector coil, causing the coil current to rise rapidly to the first peak current value Ip1 in a very short time and maintain it for a short period of time Tp1; This step provides a strong initial electromagnetic pull, enabling the armature assembly (including the armature and valve core) to quickly and reliably overcome maximum static friction, mechanical jamming, and the preload of the return spring, achieving rapid start-up and initial acceleration. At the start of the injection command, the ECU controls the drive circuit to apply a high voltage to the injector coil, causing the coil current to rapidly rise to the first peak current value Ip1 within a very short time (e.g., 0.1-1 ms, preferably 0.1-0.5 ms). The value of Ip1 is typically high (e.g., 80%-150% of the rated current) and is maintained for a short period Tp1 (e.g., 0.3-1.0 ms). The combination of Ip1 and Tp1 ensures sufficient impulse for the valve core to quickly disengage from the valve seat and enter the high-speed motion phase.

[0019] (b) Second peak current stage (Peak2): Reduce the coil current to the second peak current value Ip2 and maintain it for a period of time Tp2; After the armature assembly has undergone the first peak acceleration and is approaching but not yet at the fully open limit position, its dynamic force is finely adjusted to achieve a "soft landing." After the first peak phase, the current does not drop directly to the holding current, but first drops to or is adjusted to a second peak current value Ip2, and is maintained for a period of time Tp2 (e.g., 0.2-0.8 ms). The key role of this stage is that, under conditions of high system back pressure or requiring extremely fast response, Ip2 can be set close to or slightly lower than Ip1 to supplement the electromagnetic force, ensuring that the valve core can overcome the increased gas resistance and quickly reach the fully open position. Under normal or extremely durable conditions, Ip2 can be set significantly lower than Ip1, but still higher than the subsequent holding current Ih (i.e., the second peak current value Ip2 is greater than the holding current value Ih and the second peak current value Ip2 is less than the first peak current value Ip1). At this point, the electromagnetic force is moderately reduced, which is equivalent to applying an "electromagnetic damping" to the high-speed moving armature assembly, slowing down its kinetic energy growth and allowing it to reach the mechanical limit position (or the position maintaining a preset distance from the iron core) at a gentler speed, fundamentally reducing the impact energy of the collision. Ip2 and Tp2 are two key calibrable parameters. The ECU can query a preset mapping table based on real-time operating conditions (such as fuel rail pressure, battery voltage, injector temperature, etc.) and dynamically adjust these two parameters to achieve optimal dynamic control.

[0020] (c) Hold current phase: The coil current is then reduced to the hold current value Ih and maintained for the entire remaining injection pulse width time Th.

[0021] With minimal energy consumption, the valve core is stably maintained at its maximum lift position, ensuring a constant fuel flow cross-sectional area and achieving precise flow control. After the second peak phase, the current drops to a low holding current value Ih and is maintained throughout the remaining injection pulse width time Th. The magnitude of Ih is just sufficient to balance the return spring force, preventing the valve from closing, while avoiding excessive electromagnetic force that would cause unnecessary energy consumption and heat generation.

[0022] The powerful advantage of this drive waveform lies in its fully flexible parameter adjustment capability. The ECU can store multiple sets of waveform parameters (Ip1, Tp1, Ip2, Tp2, Ih) optimized for different engine operating conditions (such as idling, medium load, full load, cold start, and warm-up). For example, under high engine load and high fuel pressure, larger Ip1 and Ip2 can be selected to ensure response speed. Under idling or low load with low fuel injection conditions, smaller Ip1 and Ip2 can be selected, and Ip2 and Tp2 can be adjusted to focus on optimizing the landing speed for quiet operation and long service life. The drive circuit can use pulse width modulation (PWM) technology to precisely generate and adjust these current steps.

[0023] This invention relates to a dual-peak holding drive waveform control method for electromagnetic ammonia-hydrogen gas fuel injectors. Without altering the injector's mechanical structure, it achieves precise current regulation in three stages within a single drive cycle (i.e., the injection pulse width time Th, i.e., the time of Peak1 + Peak2 + Hold) entirely through innovative electronic control software. This allows for "active deceleration" of the armature movement during the second peak (Peak2) stage, achieving a smooth and controlled arrival at the fully open position, significantly reducing mechanical shock, and ensuring high consistency between valve core lift and the fully open position in each injection, thereby improving the accuracy of gas fuel metering. Specifically, this is reflected in: (1) Through active speed management in Peak2 stage, the moving parts are "soft landing", which directly and significantly reduces the mechanical impact wear caused by lack of damping of the gas injector, effectively extends the life of the injector core, and provides a purely electric control and efficient solution to solve the pain point of the industry.

[0024] (2) The smooth and controlled opening process ensures that the trajectory and end position of the valve core are highly consistent each time. Combined with the stable Hold phase, this makes the quality of the gaseous fuel injected each time more accurate, which helps to improve the emission level and combustion efficiency of the engine.

[0025] (3) Due to the small impact and residual vibration at the opening end, the valve core is more stable at the end of the drive. Combined with the control of the current cut-off rate, it can achieve faster and cleaner closing, reducing leakage or metering errors during the closing process.

[0026] (4) Enhanced adaptability and control flexibility: The five core parameters (Ip1, Tp1, Ip2, Tp2, Ih) can be calibrated independently, providing unprecedented freedom to match various complex working conditions, enabling a single injector to maintain high performance over a wider range of working conditions.

[0027] (5) Reduced cost and complexity: Compared with adding physical damping devices or adopting dual-coil hardware solutions, this invention can be implemented simply by upgrading ECU software and calibration data, without modifying the injector body hardware. It has the advantages of simple implementation, low cost and high reliability.

[0028] Specifically, such as Figure 2 As shown, under a fuel pressure of 9 bar and the engine's maximum torque condition, to ensure the response speed of the injection solenoid valve, Ip1=8A, Tp1=1ms, Ip2=6A, Tp2=1.2ms, and Ih=1.5A. If the fuel pressure drops below 7 bar, Ip1=8A, Tp1=0.8ms, Ip2=4A, Tp2=1.2ms, and Ih=1.5A. This reduces the Tp1 time and the Ip2 current, thus ensuring the response speed of the injection solenoid valve while significantly reducing mechanical shock and improving the injector's durability.

[0029] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for controlling a dual-peak holding drive waveform in an electromagnetic ammonia-hydrogen gas fuel injector, characterized in that, It includes the following steps: (a) Apply a high voltage to the injector coil, causing the coil current to rise rapidly to the first peak current value Ip1 in a very short time and maintain it for a short time Tp1; (b) Reduce the coil current to the second peak current value Ip2 and maintain it for a period of time Tp2; (c) The coil current is then reduced to the holding current value Ih and maintained for the entire remaining injection pulse width time Th.

2. The dual-peak holding drive waveform control method for an electromagnetic ammonia-hydrogen gas fuel injector according to claim 1, characterized in that: In step (a), when the injection command begins, the ECU controls the drive circuit to apply a high voltage to the injector coil.

3. The dual-peak holding drive waveform control method for an electromagnetic ammonia-hydrogen gas fuel injector according to claim 1 or 2, characterized in that: In step (a), the extremely short time is 0.1-1ms, preferably 0.1-0.5ms; the short time Tp1 is 0.3-1.0ms.

4. The dual-peak holding drive waveform control method for an electromagnetic ammonia-hydrogen gas fuel injector according to claim 1 or 2, characterized in that: In step (a), the first peak current value Ip1 is 80%-150% of the rated current.

5. The dual-peak holding drive waveform control method for an electromagnetic ammonia-hydrogen gas fuel injector according to claim 1, characterized in that: In step (b), the second peak current value Ip2 is greater than the holding current value Ih and the second peak current value Ip2 is less than the first peak current value Ip1.

6. The dual-peak holding drive waveform control method for an electromagnetic ammonia-hydrogen gas fuel injector according to claim 5, characterized in that: In step (b), the time period Tp2 is 0.2-0.8 ms.

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