Combined control system and protection method of hydrogen-rich gas internal combustion engine

Abstract

The invention relates to the technical field of internal combustion engine control, and discloses a combined control system and protection method for a hydrogen-rich gas internal combustion engine, comprising the following steps: acquiring operating parameters of the internal combustion engine in real time, the operating parameters at least comprising a gas source hydrogen concentration value, an average cylinder temperature, a vortex exhaust temperature and a current output power; and through a'priority decoupling 'strategy, after lambda reaches a lean-burn stability limit, the variable is forcibly locked, and seamless switching to EGR combustion speed reduction and ignition phase delay is achieved. The combustion speed of hydrogen-rich gas fuel is reduced through EGR, ignition delay resists the fast combustion characteristic of hydrogen to restrain detonation pressure, a proper ignition advance angle is matched according to different hydrogen concentration values, lambda and EGR rates, and the problems that only by adjusting the excess air coefficient, the system is extremely prone to death under the hydrogen-rich working condition, the lean burn limit can be touched due to the fact that lambda is increased for cooling, and the combustion efficiency is low are solved. And combustion is unstable, and the defect that the combustion speed of hydrogen is too high and knocking occurs due to the fact that lambda is reduced for stable combustion is overcome.

Description

Technical Field

[0001] This invention relates to the field of internal combustion engine control technology, specifically to a combined control system and protection method for a hydrogen-rich gas internal combustion engine. Background Technology

[0002] With the transformation of the energy structure, hydrogen-rich fuels such as biomass gas and industrial exhaust gas are being widely used in the field of internal combustion engine power generation. A significant characteristic of these gas sources is their large fluctuation in composition, with hydrogen content potentially varying drastically between 1% and 30%.

[0003] In existing technologies, the control of this type of internal combustion engine typically employs a single method of excess air coefficient adjustment. That is, based on feedback from the oxygen sensor, when the cylinder temperature is too high, the throttle valve is opened wider or the gas valve is closed narrower to increase λ, utilizing lean combustion to lower the cylinder temperature.

[0004] However, this single-variable control faces physical limitations under hydrogen-rich conditions: on the one hand, when the mixture is too lean, the flame propagation speed will drop rapidly, leading to unstable combustion or even misfire; on the other hand, high hydrogen content causes the laminar flame speed to increase exponentially, and relying solely on lean combustion cannot maintain low exhaust temperature while suppressing detonation.

[0005] In addition, existing gas composition detection usually relies on expensive online gas analyzers, whose response time is usually lagging behind the engine's combustion cycle, making it difficult to cope with transient and drastic fluctuations in gas composition, resulting in lag in the control system.

[0006] Therefore, there is an urgent need for a combined control system that can decouple the control of combustion speed and combustion temperature and respond quickly to changes in gas composition. Summary of the Invention

[0007] This invention provides a combined control system and protection method for a hydrogen-rich gas internal combustion engine, solving the problems mentioned in the background art.

[0008] This invention provides the following technical solution: a combined control and protection method for a hydrogen-rich gas internal combustion engine, comprising the following steps: S1: Real-time acquisition of internal combustion engine operating parameters, including at least the gas source hydrogen concentration, average cylinder temperature, after-scroll exhaust temperature, and current output power; S2: Determine the current fuel combustion rate level based on the hydrogen concentration value of the gas source, and match the basic control target from the preset three-dimensional control map; S3: Based on the deviation between the average cylinder temperature and the preset target temperature range, calculate the target values ​​of three control variables: excess air coefficient, ignition advance angle, and EGR valve opening. S4: Wherein, the collaborative computing follows the following priority logic: When the average cylinder temperature exceeds the preset target temperature range, the intake air flow rate is adjusted first to increase the excess air coefficient. When the excess air coefficient reaches the preset lean-burn stability limit and the average cylinder temperature still exceeds the preset target temperature range, the excess air coefficient is kept constant, while the EGR valve opening is increased and the ignition advance angle is delayed. S5: Drive the actuator to respond to the calculated target value of the control variable, and perform closed-loop correction based on the real-time feedback of the average cylinder temperature.

[0009] As a preferred technical solution of the present invention, the method for obtaining the hydrogen concentration value of the gas source includes: Direct measurement using a physical gas analyzer; or The estimation is performed using a virtual component observer, and the estimation process includes: The crankshaft position signal is acquired to calculate the instantaneous angular acceleration, and the cylinder pressure signal is acquired to calculate the combustion center of gravity; Using the laminar flame velocity characteristic spectrum pre-stored in the controller, the change in hydrogen concentration in the gas source is inferred from the advance of the combustion center of gravity. When the combustion center of gravity is detected to be ahead of the reference value and the intake pressure remains unchanged, it is determined that the hydrogen concentration value of the gas source has increased.

[0010] As a preferred embodiment of the present invention, the step of collaboratively calculating the target values ​​of the three control variables specifically employs a model predictive control algorithm: A multivariable controller incorporating cylinder temperature prediction and knock prediction models is established in the controller. Under the constraints of the excess air coefficient being less than the misfire limit and the ignition advance angle being less than the knock limit, the optimal control sequence for the future preset quantity control cycle is calculated so that the average cylinder temperature approaches the preset target temperature range. The first value of the optimal control sequence is output as the control command for the current excess air coefficient, ignition advance angle, and EGR valve opening.

[0011] As a preferred embodiment of the present invention, for operating conditions where the hydrogen concentration in the gas source is greater than 20%, the collaborative calculation further includes a feedforward compensation strategy: Establish a feedforward channel with the hydrogen concentration of the gas source as the independent variable; As the concentration of hydrogen in the gas source increases, the ignition advance angle is linearly reduced according to the first preset proportional coefficient, while the opening of the EGR valve is increased according to the second preset proportional coefficient. The rate of increase of the EGR valve opening is configured to be positively correlated with the rate of increase of the average cylinder temperature.

[0012] As a preferred embodiment of the present invention, the method further includes a hierarchical protection mechanism: When the instantaneous rate of increase of the average cylinder temperature exceeds the preset rate of change threshold, the first-level protection is triggered, and the ignition advance angle is instantaneously delayed by 3 to 5 degrees of crankshaft rotation. When the average cylinder temperature is still higher than the physical limit temperature after adjusting the excess air coefficient, ignition advance angle and EGR valve opening, the secondary protection is triggered and the fuel cut-off and cooling strategy is executed. The fuel cut-off and cooling strategy is as follows: while keeping the throttle opening unchanged, the combustion injection and ignition of some cylinders are cut off according to a preset circulation mode, and the unburned cold air pumped in is used to directly cool the inner wall of the cylinder.

[0013] As a preferred embodiment of the present invention, the determination criterion for the lean-burn stability limit is the combustion variation coefficient; When the combustion variation coefficient monitored in real time exceeds the preset stability threshold, it is determined that the excess air coefficient has reached the lean-burn stability limit. The preset stability threshold is set to 2% to 5%.

[0014] A combined control system for a hydrogen-rich gas internal combustion engine, comprising: A sensor assembly, arranged on an internal combustion engine, is used to collect operating parameters in real time. The sensor assembly includes at least a thermocouple cylinder temperature sensor arranged on the cylinder head, a wide-range oxygen sensor arranged on the exhaust pipe, a crankshaft position sensor, and a cylinder pressure sensor. A controller, communicatively connected to the sensor assembly, is configured to perform the method as described in any one of claims 1 to 6; An actuator is electrically connected to and driven by the controller, and the actuator includes an electronic throttle valve, an independent ignition coil, a gas metering valve, and an electronically controlled EGR valve. The EGR loop is connected between the exhaust side and the intake side of the internal combustion engine; The EGR loop is configured as a low-pressure EGR loop, with its intake port located downstream of the turbine outlet of the turbocharger and its injection port located upstream of the compressor inlet of the turbocharger. Alternatively, the EGR loop may include a Venturi mixer located in the intake manifold, with the outlet of the EGR loop connected to the throat of the Venturi mixer.

[0015] As a preferred embodiment of the present invention, the controller is pre-loaded with suitable operating range data: The suitable operating range is defined as an average cylinder temperature between 320 degrees Celsius and 420 degrees Celsius; The controller is configured to: issue a command to reduce the EGR valve opening or advance the ignition timing when the average cylinder temperature is below 320 degrees Celsius; and issue a combined cooling command when the average cylinder temperature is above 420 degrees Celsius.

[0016] As a preferred embodiment of the present invention, the EGR circulation loop further includes an EGR cooler connected in series between the gas intake port and the gas injection port; The controller is configured to monitor the outlet temperature of the EGR cooler and ensure that the exhaust gas temperature entering the compressor inlet is maintained within a preset EGR temperature range. The preset EGR temperature range is 55 degrees Celsius to 65 degrees Celsius.

[0017] The present invention has the following beneficial effects: 1. By employing a "priority decoupling" strategy, once λ reaches the lean-burn stability limit, this variable is forcibly locked, and the system seamlessly switches to EGR heat capacity dilution and ignition phase delay. EGR increases the specific heat capacity of the working fluid to absorb heat, while ignition delay counteracts the rapid combustion characteristics of hydrogen to suppress detonation. Through a phased synergistic strategy, this addresses the problem that existing technologies, which rely solely on adjusting the excess air coefficient, are prone to dead ends under hydrogen-rich conditions. Increasing λ to cool the system can lead to touching the lean-burn limit and combustion instability, while decreasing λ to stabilize combustion can cause excessively rapid hydrogen combustion and detonation.

[0018] 2. By utilizing the positive correlation between hydrogen concentration and laminar flame velocity, and by monitoring the changes in crankshaft instantaneous angular acceleration and cylinder pressure CA50, cycle-by-cycle feedforward control of gas source composition fluctuations is achieved. This effectively suppresses transient knocking caused by sudden changes in composition and solves the problem that physical gas analyzers have long response times and cannot cope with transient changes in gas source.

[0019] 3. The "fuel cut-off and cooling" strategy is adopted. While cutting off the fuel supply, the throttle is kept fully open. The large amount of low-temperature air pumped in directly cools the cylinder wall. This reduces power and eliminates hot spots in the cylinder, blocking the mechanism of pre-ignition. This solves the problem that traditional throttle power reduction reduces intake air volume, weakens heat dissipation, and easily induces hydrogen-rich pre-ignition.

[0020] 4. The low-pressure EGR (LP-EGR) loop design based on differential pressure drive is adopted, which utilizes the negative pressure zone of the compressor to draw in exhaust gas, eliminating the need to add an EGR pump and reducing system costs. Attached Figure Description

[0021] Figure 1 This is a hardware architecture diagram of the internal combustion engine combined control system provided in an embodiment of the present invention.

[0022] Figure 2 This is a schematic diagram of a low-voltage EGR circuit provided in an embodiment of the present invention.

[0023] Figure 3 A flowchart of the collaborative control logic provided for embodiments of the present invention.

[0024] Figure 4 This is a block diagram of a high-order control principle based on MPC and virtual sensing.

[0025] Figure 5 This is a comparison chart of the response curves of the control variables under different hydrogen contents in the examples. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] Example 1 This embodiment provides a combined control and protection method for a hydrogen-rich gas internal combustion engine, aiming to solve the problem of heat load management when the gas source composition fluctuates. This method is mainly executed by a controller, which can be an electronic control unit (ECU).

[0028] A combined control and protection method for a hydrogen-rich gas internal combustion engine includes the following steps: S1: Real-time acquisition of internal combustion engine operating parameters, including at least the gas source hydrogen concentration, average cylinder temperature, after-scroll exhaust temperature, and current output power; S2: Determine the current fuel combustion rate level based on the hydrogen concentration value of the gas source, and match the basic control target from the preset three-dimensional control map; S3: Based on the deviation between the average cylinder temperature and the preset target temperature range, the target values ​​of three control variables are calculated collaboratively: excess air coefficient, ignition advance angle, and EGR valve opening. S4: Among them, collaborative computing follows the following priority logic: When the average cylinder temperature exceeds the preset target temperature range, the intake air flow rate is adjusted first to increase the excess air coefficient. When the excess air coefficient reaches the preset lean-burn stability limit and the average cylinder temperature still exceeds the preset target temperature range, the excess air coefficient is kept constant, while the EGR valve opening is increased and the ignition advance angle is delayed. S5: Drive the actuator to respond to the calculated target value of the control variable and perform closed-loop correction based on the average cylinder temperature fed back in real time.

[0029] In a preferred embodiment, the method for obtaining the hydrogen concentration value of the gas source includes: Direct measurement using a physical gas analyzer; or The estimation is performed using a virtual component observer, and the estimation process includes: The crankshaft position signal is acquired to calculate the instantaneous angular acceleration ω, and the cylinder pressure signal is acquired to calculate the combustion center of gravity (CA50). By using the laminar flame velocity characteristic spectrum pre-stored in the controller, the change in hydrogen concentration in the gas source is inferred from the advance of the combustion center of gravity. When the combustion center of gravity is detected to be ahead of the reference value and the intake pressure remains unchanged, it is determined that the hydrogen concentration value of the gas source has increased.

[0030] In a preferred embodiment: the step of collaboratively calculating the target values ​​of the three control variables specifically employs a model predictive control algorithm. A multivariable controller incorporating cylinder temperature prediction and knock prediction models is established in the controller. Under the constraints of the excess air coefficient being less than the misfire limit and the ignition advance angle being less than the knock limit, the optimal control sequence for the future preset quantity control cycle is calculated so that the average cylinder temperature approaches the preset target temperature range. The first value of the optimal control sequence is output as the control command for the current excess air coefficient, ignition advance angle, and EGR valve opening.

[0031] In a preferred embodiment: for operating conditions where the hydrogen concentration in the gas source is greater than 20%, the collaborative calculation also includes a feedforward compensation strategy: Establish a feedforward channel with the hydrogen concentration of the gas source as the independent variable; As the concentration of hydrogen in the gas source increases, the ignition advance angle is linearly reduced according to the first preset proportional coefficient, while the opening of the EGR valve is increased according to the second preset proportional coefficient. The rate of increase of the EGR valve opening is configured to be positively correlated with the rate of increase of the average cylinder temperature.

[0032] In a preferred embodiment, the method further includes a hierarchical protection mechanism: When the instantaneous rate of increase of the average cylinder temperature exceeds the preset rate of change threshold, the first-level protection is triggered, and the ignition advance angle is instantaneously delayed by 3 to 5 degrees of crankshaft rotation. When the average cylinder temperature is still higher than the physical limit temperature after adjusting the excess air coefficient, ignition advance angle and EGR valve opening, the secondary protection is triggered and the fuel cut-off and cooling strategy is executed. The fuel cut-off and cooling strategy is as follows: while keeping the throttle opening unchanged, the fuel injection and ignition of some cylinders are cut off according to the preset circulation mode, and the unburned cold air pumped in is used to directly cool the inner wall of the cylinder.

[0033] In a preferred embodiment: the lean-burn stability limit is determined based on the combustion variation coefficient; When the real-time monitored combustion variation coefficient exceeds the preset stability threshold, it is determined that the excess air coefficient has reached the lean-burn stability limit. The preset stability threshold is set to 2% to 5%.

[0034] In practice, the controller first performs operating condition sensing.

[0035] Signal acquisition: The controller acquires electrical signals emitted by the sensor components in real time through the A / D interface, specifically including: the hydrogen concentration value CH2 of the gas source, the average cylinder temperature Tcyl fed back by the thermocouple, the exhaust temperature Texh after the turbine, and the current output power Pload.

[0036] Preset parameters: The following control boundary parameters are pre-stored in the controller's non-volatile memory EEPROM: suitable operating range Tcyl∈[320∘C,420∘C], and lean-burn stability limit λlimit=2.0.

[0037] When the controller detects a change in the hydrogen concentration in the gas source, causing the average cylinder temperature to rise and exceed the preset target temperature range Tcyl > 420°C, the controller enters the decoupling control phase. In this phase, the controller generates control commands based on priority logic. Phase 1: Air-dominated regulation Judgment conditions: The controller determines that Tcyl > 420∘C and the current excess air coefficient λ < λlimit.

[0038] Control actions: The controller sends a PWM signal to the electronic throttle drive circuit to increase the duty cycle and open the throttle wider; or sends an opening command to the air bypass valve.

[0039] Physical effects: Increases the amount of fresh air intake, raising the excess air coefficient λ to 1.9. The heat capacity of the excess air is used to lower the combustion temperature. During this process, the controller continuously reads the coefficient of variation (COV) from the combustion analysis unit.

[0040] Phase 2: Multivariate Coordination Judgment conditions: The controller detects that λ has reached the lean-burn stability limit (λ reaches 2.0, or the real-time COV exceeds the preset threshold by 3%), but the average cylinder temperature Tcyl has not yet dropped below 420℃.

[0041] Control Actions: The controller automatically switches control logic and executes the following parallel operations: Lock λ: Prevents the electronic throttle opening from increasing further, maintaining λ at its current value.

[0042] Increase EGR valve opening: The controller sends a control signal to the electronically controlled EGR valve, linearly increasing the valve opening from 0% to 30%. This allows the exhaust gas (containing CO2 and H2O) to be cooled and then flow back to the intake duct, where its high specific heat capacity is used to absorb heat.

[0043] Ignition advance: The controller sends a signal to the ignition drive module to delay the ignition advance angle θign from 22°BTDC to 16°BTDC. This shifts the combustion center of gravity (CA50) backward, avoiding the high-temperature and high-pressure zone near the top dead center of the compressor.

[0044] Example 2: Control Strategy Based on Virtual Sensing and MPC For scenarios where no physical hydrogen analyzer is available, the controller uses a pre-calibrated laminar flame velocity characteristic map to infer the hydrogen content.

[0045] Physical signal acquisition: The high-speed counter module of the controller receives the pulse signal from the crankshaft position sensor and calculates the instantaneous angular acceleration ω; at the same time, it acquires the cylinder pressure sensor signal through the analog interface.

[0046] Feature extraction algorithm: The controller runs a thermodynamic calculation program to calculate the combustion center of gravity (CA50) based on the cylinder pressure curve.

[0047] Map construction and storage: A multidimensional lookup table is stored in the controller's memory. The multidimensional lookup table can be obtained based on bench calibration experiments. Its input indices are inlet pressure, rotational speed, and λ, and the output value is the baseline combustion center of gravity deviation ΔCA50. It records the change in laminar flame velocity and the corresponding reaction data for each 10% increase in hydrogen content under the same operating conditions.

[0048] Online application logic: The controller looks up the table in real time. When the measured CA50 is significantly earlier than the reference value and the intake pressure sensor reading does not change significantly, the controller queries the Map to deduce the hydrogen concentration value of the gas source.

[0049] For the calculation of control variables, the controller uses the model predictive control (MPC) algorithm.

[0050] Predictive model construction: A linearized state-space model is integrated within the controller. The parameters of the linearized state-space model are obtained through system identification: In bench tests, pseudo-random binary sequence (PRBS) excitations are applied to the input variables (λ, θign, EGR valve opening), the cylinder temperature output response is collected, and the model coefficients are identified using the least squares method.

[0051] Model format: Tcyl(k+1)=0.9⋅Tcyl(k)+5.2⋅ΔH2%−1.5⋅Δλ−2.0⋅ΔRegr+0.5⋅Δθign Objective function solution: In each control cycle, the controller solves a quadratic programming (QP) problem to minimize the objective function J.

[0052] J=w1(Tcyl−Ttarget)2+w2(Δλ)2+w3(Δθ)2+w4(ΔEGR)2 Here, w1 to w4 are preset weighting coefficients. This function aims to bring the cylinder temperature close to the target value while penalizing drastic fluctuations in the control quantity.

[0053] Constraint execution: The solution process is subject to hard constraints: λ≤2.2 (misfire limit), θign≤θknock (knock limit). The controller outputs the first set of values ​​of the optimal control sequence to drive the actuator.

[0054] Example 3: Hierarchical Protection Mechanism To prevent engine damage under extreme operating conditions, the controller is equipped with graded protection logic.

[0055] Level 1 protection (transient thermal shock protection): Triggering condition: The controller calculates the derivative value dT / dt of the average cylinder temperature. Triggering occurs when this value exceeds a preset threshold of 10∘C / s.

[0056] Action executed: The controller not only outputs the regular control signal, but also adds an emergency correction, instantly delaying the ignition advance angle θign by 3 to 5 degrees of crankshaft rotation. This action has the highest priority interrupt privileges.

[0057] Level 2 protection (fuel cut-off cold trailer protection): Triggering condition: After the above adjustment is performed, the average cylinder temperature Tcyl remains above the physical limit temperature for a preset time.

[0058] Action executed: The controller executes the fuel cut-off and cold-dragging strategy. Maintain intake: Keep the electronic throttle fully open to ensure maximum air intake.

[0059] Injection cut-off: The controller sends a command to the gas injection valve to periodically block the injection pulses according to a preset cycle pattern.

[0060] During the fuel cut-off cycle, cold fresh air flows directly through the 430°C cylinder wall, utilizing the internal cooling effect to generate strong forced convection heat transfer, thereby quickly removing accumulated heat and eliminating pre-ignition hotspots.

[0061] Example 4: Figure 1As shown, this embodiment provides a combined control system for a hydrogen-rich gas internal combustion engine. The system mainly includes sensor components, a controller, and actuators.

[0062] A combined control system for a hydrogen-rich gas internal combustion engine, comprising: The sensor assembly is arranged on the internal combustion engine to collect operating parameters in real time. The sensor assembly includes at least a thermocouple cylinder temperature sensor arranged in the cylinder head, a wide-range oxygen sensor arranged in the exhaust pipe, a crankshaft position sensor, and a cylinder pressure sensor. The controller, which is in communication with the sensor assembly, is configured to execute a combined control method for the hydrogen-rich gas internal combustion engine. The actuator is electrically connected to and driven by the controller, and includes an electronic throttle valve, an independent ignition coil, a gas metering valve, and an electronically controlled EGR valve. The EGR loop is connected between the exhaust side and the intake side of the internal combustion engine. The EGR loop is configured as a low-pressure EGR loop, with its intake port located downstream of the turbine outlet of the turbocharger and its injection port located upstream of the compressor inlet of the turbocharger. Alternatively, the EGR loop may include a Venturi mixer located in the intake manifold, with the outlet of the EGR loop connected to the throat of the Venturi mixer.

[0063] In a preferred embodiment: the controller has preset data for a suitable operating range. The suitable operating range is defined as an average cylinder temperature between 320 degrees Celsius and 420 degrees Celsius; The controller is configured to: issue a command to reduce the EGR valve opening or advance the ignition timing when the average cylinder temperature is below 320 degrees Celsius; and issue a combined cooling command when the average cylinder temperature is above 420 degrees Celsius.

[0064] In a preferred embodiment, the EGR circulation loop further includes an EGR cooler connected in series between the intake port and the injection port; The controller is configured to monitor the outlet temperature of the EGR cooler and ensure that the exhaust gas temperature entering upstream of the compressor inlet is maintained within the preset EGR temperature range; The preset EGR temperature range is 55 degrees Celsius to 65 degrees Celsius.

[0065] The sensor assembly is located on the internal combustion engine to collect operating data. Specifically, it includes: a thermocouple cylinder temperature sensor mounted below the spark plug seat in the cylinder head to collect the average cylinder temperature Tcyl; a wide-range oxygen sensor mounted on the exhaust manifold to collect the excess air coefficient; and a crankshaft position sensor and a cylinder pressure sensor.

[0066] The controller is communicatively connected to the aforementioned sensor components. The controller includes a processor and a memory, the memory storing a computer program. When the program is executed by the processor, it implements the joint control method for the hydrogen-rich gas internal combustion engine as described in Examples 1 to 3. The controller is configured to receive sensor signals, perform strategy addressing and decoupling calculations, and output drive signals.

[0067] The actuator is driven by a controller and includes an electronic throttle valve for regulating intake air volume, an independent ignition coil and a gas metering valve for controlling combustion, and an electronically controlled EGR valve for regulating exhaust gas recirculation.

[0068] The EGR loops are as follows: Implementation method A (low-pressure EGR): as follows Figure 2 As shown, the EGR loop is configured as a low-pressure EGR (LP-EGR) architecture. Its intake port is located downstream of the turbocharger's turbine outlet, and its injection port is located upstream of the turbocharger's compressor inlet. Exhaust gas is drawn from the intake port, flows through the EGR cooler for cooling, and the controller adjusts the cooling water flow rate by monitoring the outlet temperature sensor to maintain the outlet temperature at 55-65°C. The flow rate is further regulated by the EGR valve, and the exhaust gas ultimately mixes with fresh air before entering the compressor. This architecture utilizes the natural negative pressure before the compressor to drive the exhaust gas, eliminating the need for an additional EGR pump.

[0069] Implementation Method B (Venturi Ejector): In another implementation method, the EGR loop's injection port is connected to the throat of a Venturi mixer located on the intake manifold. The exhaust gas is drawn into the intake manifold using the localized negative pressure generated when the high-speed intake airflow passes through the Venturi tube. This method is suitable for models with natural aspiration or insufficient intake negative pressure.

[0070] Comparison of options: Comparative Example 1 (Prior Art): Only a single excess air coefficient (λ) closed-loop control is used. When the cylinder temperature rises, the temperature is reduced only by increasing λ.

[0071] This application's embodiment employs the λ+EGR+θign joint decoupling control of the present invention.

[0072] Test Result Analysis: Conclusion: Experimental data fully demonstrates that, under hydrogen-rich operating conditions, single-variable control cannot simultaneously resolve the contradiction between "cooling" and "stable combustion" (resulting in a trade-off). However, this invention, through decoupled control logic with specific priorities, successfully controls the thermal load (cylinder temperature, detonation pressure) within a safe range while ensuring stable combustion (COV < 3%), achieving unexpected technical results and demonstrating significant inventiveness.

[0073] Example 5: This invention also provides a non-transitory computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the steps of the combined control method for the hydrogen-rich gas internal combustion engine provided in the above embodiments.

[0074] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0075] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended technical solutions and their equivalents.

Claims

1. A combined control and protection method for a hydrogen-rich gas internal combustion engine, characterized in that, Includes the following steps: S1: Real-time acquisition of internal combustion engine operating parameters, including at least the gas source hydrogen concentration, average cylinder temperature, after-scroll exhaust temperature, and current output power; S2: Determine the current fuel combustion rate level based on the hydrogen concentration value of the gas source, and match the basic control target from the preset three-dimensional control map; S3: Based on the deviation between the average cylinder temperature and the preset target temperature range, calculate the target values ​​of three control variables: excess air coefficient, ignition advance angle, and EGR valve opening. S4: Wherein, the collaborative computing follows the following priority logic: When the average cylinder temperature exceeds the preset target temperature range, the intake air flow rate is adjusted first to increase the excess air coefficient. When the excess air coefficient reaches the preset lean-burn stability limit and the average cylinder temperature still exceeds the preset target temperature range, the excess air coefficient is kept constant, while the EGR valve opening is increased and the ignition advance angle is delayed. S5: Drive the actuator to respond to the calculated target value of the control variable, and perform closed-loop correction based on the real-time feedback of the average cylinder temperature.

2. The combined control and protection method for a hydrogen-rich gas internal combustion engine according to claim 1, characterized in that, The method for obtaining the hydrogen concentration value of the gas source includes: Direct measurement using a physical gas analyzer; or The estimation is performed using a virtual component observer, and the estimation process includes: The crankshaft position signal is acquired to calculate the instantaneous angular acceleration, and the cylinder pressure signal is acquired to calculate the combustion center of gravity; Using the laminar flame velocity characteristic spectrum pre-stored in the controller, the change in hydrogen concentration in the gas source is inferred from the advance of the combustion center of gravity. When the combustion center of gravity is detected to be ahead of the reference value and the intake pressure remains unchanged, it is determined that the hydrogen concentration value of the gas source has increased.

3. The combined control and protection method for a hydrogen-rich gas internal combustion engine according to claim 1, characterized in that, The step of collaboratively calculating the target values ​​of the three control variables specifically employs a model predictive control algorithm: A multivariable controller incorporating cylinder temperature prediction and knock prediction models is established in the controller. Under the constraints of the excess air coefficient being less than the misfire limit and the ignition advance angle being less than the knock limit, the optimal control sequence for the future preset quantity control cycle is calculated so that the average cylinder temperature approaches the preset target temperature range. The first value of the optimal control sequence is output as the control command for the current excess air coefficient, ignition advance angle, and EGR valve opening.

4. The combined control and protection method for a hydrogen-rich gas internal combustion engine according to claim 1, characterized in that, For operating conditions where the hydrogen concentration in the gas source is greater than 20%, the collaborative calculation also includes a feedforward compensation strategy: Establish a feedforward channel with the hydrogen concentration of the gas source as the independent variable; As the concentration of hydrogen in the gas source increases, the ignition advance angle is linearly reduced according to the first preset proportional coefficient, while the opening of the EGR valve is increased according to the second preset proportional coefficient. The rate of increase of the EGR valve opening is configured to be positively correlated with the rate of increase of the average cylinder temperature.

5. The combined control and protection method for a hydrogen-rich gas internal combustion engine according to claim 1, characterized in that, This method also includes a tiered protection mechanism: When the instantaneous rate of increase of the average cylinder temperature exceeds the preset rate of change threshold, the first-level protection is triggered, and the ignition advance angle is instantaneously delayed by 3 to 5 degrees of crankshaft rotation. When the average cylinder temperature is still higher than the physical limit temperature after adjusting the excess air coefficient, ignition advance angle and EGR valve opening, the secondary protection is triggered and the fuel cut-off and cooling strategy is executed. The fuel cut-off and cooling strategy is as follows: while keeping the throttle opening unchanged, the combustion injection and ignition of some cylinders are cut off according to a preset circulation mode, and the unburned cold air pumped in is used to directly cool the inner wall of the cylinder.

6. The combined control and protection method for a hydrogen-rich gas internal combustion engine according to claim 1, characterized in that, The determination of the lean-burn stability limit is based on the combustion variation coefficient; When the combustion variation coefficient monitored in real time exceeds the preset stability threshold, it is determined that the excess air coefficient has reached the lean-burn stability limit. The preset stability threshold is set to 2% to 5%.

7. A combined control system for a hydrogen-rich gas internal combustion engine, characterized in that, include: A sensor assembly, arranged on an internal combustion engine, is used to collect operating parameters in real time. The sensor assembly includes at least a thermocouple cylinder temperature sensor arranged on the cylinder head, a wide-range oxygen sensor arranged on the exhaust pipe, a crankshaft position sensor, and a cylinder pressure sensor. A controller, communicatively connected to the sensor assembly, is configured to perform the method as described in any one of claims 1 to 6; An actuator is electrically connected to and driven by the controller, and the actuator includes an electronic throttle valve, an independent ignition coil, a gas metering valve, and an electronically controlled EGR valve. The EGR loop is connected between the exhaust side and the intake side of the internal combustion engine; The EGR loop is configured as a low-pressure EGR loop, with its intake port located downstream of the turbine outlet of the turbocharger and its injection port located upstream of the compressor inlet of the turbocharger. Alternatively, the EGR loop may include a Venturi mixer located in the intake manifold, with the outlet of the EGR loop connected to the throat of the Venturi mixer.

8. The combined control system for a hydrogen-rich gas internal combustion engine according to claim 7, characterized in that, The controller has preset data for a suitable operating range: The suitable operating range is defined as an average cylinder temperature between 320 degrees Celsius and 420 degrees Celsius; The controller is configured to: issue a command to reduce the EGR valve opening or advance the ignition timing when the average cylinder temperature is below 320 degrees Celsius; and issue a combined cooling command when the average cylinder temperature is above 420 degrees Celsius.

9. The combined control system for a hydrogen-rich gas internal combustion engine according to claim 7, characterized in that, The EGR circulation loop also includes an EGR cooler connected in series between the gas intake port and the gas injection port; The controller is configured to monitor the outlet temperature of the EGR cooler and ensure that the exhaust gas temperature entering the compressor inlet is maintained within a preset EGR temperature range. The preset EGR temperature range is 55 degrees Celsius to 65 degrees Celsius.

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