Hydrogen internal combustion engine knock suppression system and method

Abstract

The invention discloses a hydrogen internal combustion engine knock suppression method, relates to the field of internal combustion engine knock, and solves the technical problems that an existing SCR system cannot realize energy linkage of fuel and an aftertreatment system and frequently enters knock protection. The method comprises the steps that a real-time knock signal is obtained, and when the real-time knock signal meets a preset fault condition, it is judged that knock or preignition happens to the hydrogen internal combustion engine; when the hydrogen internal combustion engine is knocked or pre-ignited, an ammonia injection amount base value is obtained and corrected to obtain a target ammonia injection amount, the knock periods of the hydrogen internal combustion engine are detected, and when it is judged that the hydrogen internal combustion engine is knocked or pre-ignited in multiple continuous knock periods, knock alarming is conducted. The invention further discloses a knock suppression system of the hydrogen internal combustion engine. The condition of frequent knock protection is avoided, and the service life of the hydrogen internal combustion engine is prolonged.

Description

Technical Field

[0001] The present invention relates to the field of internal combustion engine knock, and more specifically, to a knock suppression system and method for a hydrogen internal combustion engine. Background Art

[0002] Hydrogen energy is a common type of new energy. Due to its own characteristics, hydrogen energy has many advantages compared to traditional energy sources. For example, hydrogen does not produce CO2 emissions after combustion; however, due to its high activity, it is prone to pre-ignition and knock, especially under high compression ratio and high load conditions. Traditional methods suppress knock by retarding the ignition angle or lean-burning the air-fuel mixture, but this will lead to a decrease in thermal efficiency and an increase in NOx emissions. In the prior art, the SCR system is only used for tail gas NOx treatment and fails to achieve energy linkage between the fuel and the post-treatment system to solve the problems of hydrogen pre-ignition and knock. In the field of hydrogen internal combustion engines with hydrogen-ammonia dual fuel, the independent application of liquid ammonia as a fuel or a reducing agent is relatively common. However, in the field of pure hydrogen single-fuel hydrogen internal combustion engines, there is no dual-functional coupling design that uses liquid ammonia as both a knock inhibitor and an SCR reducing agent, and it does not have the ability of system octane number self-learning, resulting in frequent entry into knock protection. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a knock suppression system and method for a hydrogen internal combustion engine in view of the deficiencies of the prior art, so as to solve the technical problems that the existing SCR system fails to achieve energy linkage between the fuel and the post-treatment system and frequently enters knock protection.

[0004] A knock suppression method for a hydrogen internal combustion engine according to the present invention is as follows: Obtain a real-time knock signal. When the real-time knock signal meets a preset fault condition, it is determined that the hydrogen internal combustion engine has knock or pre-ignition; when the hydrogen internal combustion engine has knock or pre-ignition, obtain a base ammonia injection quantity, correct the base ammonia injection quantity to obtain a target ammonia injection quantity, and detect the knock cycle of the hydrogen internal combustion engine. When it is determined that the hydrogen internal combustion engine has knock or pre-ignition for a continuous plurality of knock cycles, knock alarm is performed.

[0005] For further improvement, the method for correcting the base ammonia injection quantity is to calibrate the knock level according to the real-time knock signal;

[0006] When the knock level is L1, the target ammonia injection quantity = base ammonia injection quantity × (1 + preset knock level coefficient × (knock level - 1)), and the ignition angle of the hydrogen internal combustion engine is retarded by a preset third crank angle range × preset speed correction coefficient;

[0007] When the knock level is L2, divide the hydrogen injection pressure phase of the hydrogen internal combustion engine, advance the hydrogen injection amount of the main nozzle of the hydrogen internal combustion engine by a preset fourth crank angle phase, and reduce the hydrogen injection amount of the rear nozzle of the hydrogen internal combustion engine to a preset first hydrogen injection amount.

[0008] Furthermore, the method for obtaining the ammonia injection amount base value is as follows.

[0009] Input the real-time knock signal into a preset working condition mapping database, and query whether there is an ammonia injection amount in the working condition mapping database that matches the real-time knock signal. When there is an ammonia injection amount in the working condition mapping database that matches the real-time knock signal, use the ammonia injection amount in the working condition mapping database as the ammonia injection amount base value.

[0010] When there is no ammonia injection amount in the working condition mapping database that matches the real-time knock signal, calculate the ammonia injection amount base value through the real-time knock signal and the working conditions of the hydrogen internal combustion engine.

[0011] Even further, the expression for calculating the ammonia injection amount base value is as follows.

[0012]

[0013] Among them, AFR NH3 represents the dynamic set value, K temp represents the temperature compensation coefficient, K temp represents the pressure compensation coefficient, AFR H2 represents the theoretical air-fuel ratio of hydrogen fuel, KnockLevel represents the knock level, represents the total air flow rate, represents the hydrogen flow rate.

[0014] Even further, when the pressure phase difference ΔP_ between adjacent cylinders of the hydrogen internal combustion engine in multiple consecutive knock cycles 相邻缸 is greater than the preset phase difference threshold, it is determined that knocking or pre-ignition occurs in the hydrogen internal combustion engine during multiple consecutive knock cycles, and a continuous knock handling measure is triggered.

[0015] The continuous knock handling measure is to activate the in-cylinder direct injection ammonia curtain barrier of the hydrogen internal combustion engine, set the injection pulse width of the hydrogen internal combustion engine to be greater than or equal to the preset injection pulse width standard value, and increase the air-fuel ratio of the hydrogen internal combustion engine to the air-fuel ratio standard value.

[0016] Further, when the knock alarm is performed, SCR collaborative control measures are triggered to jointly suppress knock or pre-ignition. The SCR collaborative control measures are as follows: obtain the NOx concentration and ammonia slip at the SCR inlet of the hydrogen internal combustion engine, and control the ammonia injection amount according to the NOx concentration and ammonia slip at the SCR inlet so that the conversion efficiency of the NOx concentration is greater than or equal to a preset conversion efficiency standard value and the ammonia slip is less than or equal to a preset ammonia slip threshold.

[0017] Further, the fault conditions include a knock determination condition, a first pre-ignition determination condition, and a second pre-ignition determination condition;

[0018] The knock determination condition is that the amplitude of the real-time knock signal is greater than a preset knock signal amplitude threshold and the phase of the real-time knock signal is within a preset first crankshaft angle range after the ignition command;

[0019] The first pre-ignition determination condition is that the abnormal cylinder pressure rise rate of the hydrogen internal combustion engine is greater than a preset cylinder pressure threshold and the phase of the real-time knock signal is greater than a preset second crankshaft angle before the ignition command;

[0020] The second pre-ignition determination condition is that the phase offset of the cylinder pressure PV value detected before the exhaust valve opens is greater than a preset phase offset threshold and the combustion pressure gradient is greater than a preset combustion pressure gradient threshold;

[0021] When the knock determination condition is satisfied, it is determined that the hydrogen internal combustion engine has a knock; when both the first pre-ignition determination condition and the second pre-ignition determination condition are satisfied, it is determined that the hydrogen internal combustion engine has a pre-ignition.

[0022] A hydrogen internal combustion engine knock suppression system, the system includes,

[0023] A liquid ammonia dual-channel supply module for outputting liquid ammonia;

[0024] A knock identification module for outputting a real-time knock signal;

[0025] An ECU, which applies a hydrogen internal combustion engine knock suppression method according to any one of claims 1-7 above to control the liquid ammonia output according to the real-time knock signal to eliminate knock or pre-ignition.

[0026] For further improvement, the liquid ammonia dual-channel supply module includes a liquid ammonia storage tank and an electronically controlled three-way valve. The outlet end of the liquid ammonia storage tank is connected to the inlet end of the electronically controlled three-way valve through a pipeline. The first outlet end of the electronically controlled three-way valve is connected to the intake port injector of the hydrogen internal combustion engine through a pipeline, serving as the first liquid nitrogen branch; the second outlet end of the electronically controlled three-way valve is connected to the SCR injector of the hydrogen internal combustion engine through a pipeline, serving as the second liquid nitrogen branch.

[0027] Further, the knock identification module is a knock sensor and a crankshaft sensor, and both the knock sensor and the crankshaft sensor are electrically connected to the ECU.

[0028] Beneficial effects

[0029] The advantages of the present invention are as follows:

[0030] By this method of the present invention, real-time knock signals are obtained. When the real-time knock signals meet the preset fault conditions, it is determined that the hydrogen internal combustion engine has knocking or pre-ignition. When the hydrogen internal combustion engine has knocking or pre-ignition, the base value of ammonia injection quantity is obtained, the target ammonia injection quantity is obtained by correcting the base value of ammonia injection quantity, and the knock cycle of the hydrogen internal combustion engine is detected. When it is determined that the hydrogen internal combustion engine has knocking or pre-ignition for multiple consecutive knock cycles, knock alarm is carried out, realizing the dual-functional coupling of the knock inhibitor and the SCR reducing agent, having the self-learning of the system octane number, avoiding the situation of frequently entering the knock protection, and improving the service life of the hydrogen internal combustion engine. Description of the drawings

[0031] Figure 1 is the flowchart for obtaining the base value of ammonia injection quantity of the present invention;

[0032] Figure 2 is the schematic diagram of the overall system for knock suppression of the hydrogen internal combustion engine of the present invention;

[0033] Figure 3 is the schematic diagram of the structure of the liquid ammonia dual-channel supply module of the present invention;

[0034] Figure 4 is the schematic diagram of the structure of the knock identification module of the present invention;

[0035] Figure 5 is the calibration diagram of the knock level determination standard of the present invention. Specific embodiments

[0036] The following is a description of the present invention in conjunction with embodiments, but it does not constitute any limitation to the present invention. Any limited modifications made by anyone within the scope of the claims of the present invention are still within the scope of the claims of the present invention.

[0037] Refer to Figures 1 - 5 , a method for knock suppression of a hydrogen internal combustion engine of the present invention. This method is to obtain real-time knock signals, and when the real-time knock signals meet the preset fault conditions, it is determined that the hydrogen internal combustion engine has knocking or pre-ignition.

[0038] The fault conditions include a knock determination condition, a first pre-ignition determination condition, and a second pre-ignition determination condition.

[0039] The knock determination condition is that the amplitude of the real-time knock signal is greater than the preset knock signal amplitude threshold and the phase of the real-time knock signal is within the preset first crank angle range after the ignition command. The first crank angle range is 10°CA to 60°CA.

[0040] The first pre-ignition determination condition is that the abnormal cylinder pressure rise rate of the hydrogen internal combustion engine is greater than the preset cylinder pressure threshold and the phase of the real-time knock signal is greater than the preset second crank angle before the ignition command. The second crank angle is 5°CA and the cylinder pressure threshold is 5 bar / °CA.

[0041] The second pre-ignition determination condition is that the phase offset of the cylinder pressure PV value detected before the exhaust valve opens is greater than the preset phase offset threshold and the combustion pressure gradient is greater than the preset combustion pressure gradient threshold. The phase offset threshold is 8°CA, and the combustion pressure gradient threshold is 40 bar / °CA obtained according to the existing combustion pressure gradient standard and applying the Walsh transform.

[0042] When the knock determination condition is satisfied, it is determined that the hydrogen internal combustion engine has a knock; when both the first pre-ignition determination condition and the second pre-ignition determination condition are satisfied, it is determined that the hydrogen internal combustion engine has a pre-ignition.

[0043] Input the knock level into the constructed two-stage learning model to output the ammonia injection amount to suppress the knock or pre-ignition.

[0044] As Figure 1 shown, the method for constructing the two-stage learning model is

[0045] Establish a working condition calibration module for a four-dimensional parameter space, obtain the rotational speed, load, intake air temperature, and anti-knock value of the hydrogen internal combustion engine, and establish a working condition mapping database for the working condition calibration module based on the rotational speed, load, intake air temperature, and anti-knock value of the hydrogen internal combustion engine. The rotational speed, load, intake air temperature, and anti-knock value of the hydrogen internal combustion engine are divided by gradients.

[0046] Obtain the anti-knock value. After the monitored hydrogen internal combustion engine has a knock, the anti-knock value decreases at a certain slope until no knock signal is monitored again, and then the anti-knock value rises at a slow slope, up to 100% and down to 0%.

[0047] The two-stage learning model includes a rough learning stage model and a fine learning stage model. The rotational speed, load, intake air temperature, and anti-knock value of the hydrogen internal combustion engine in the working condition mapping database are all used as the inputs of the rough learning stage model. The output of the rough learning stage model is the target data aiming at knock elimination. The target data is used as the input of the fine learning stage model of the injection quantity optimization mode based on IT efficiency maximization. The output of the fine learning stage model is the ammonia injection quantity. After the two-stage learning is completed, the ammonia injection quantity is stored in the working condition mapping database. The weight coefficients of the parameters in the fine learning stage model are adaptively adjusted. The two-stage learning model realizes the dual-functional coupling of the knock inhibitor and the SCR reductant, has the self-learning of the system octane number, improves the efficiency of the hydrogen internal combustion engine in dealing with knock or pre-ignition, and improves the flexibility of the processing task.

[0048] The expression for obtaining the ammonia injection quantity is

[0049]

[0050] where AFR NH3 represents the dynamic set value (the knock level 1 is 6.0; the knock level 2 is 5.5; the knock level 3 is 5.0), K temp represents the temperature compensation coefficient (when the evaporator temperature is lower than 50 °C, K temp = 1.2), K temp represents the pressure compensation coefficient (when the intake pressure < 1.5 bar, K press = 1.1), AFR H2 represents the theoretical air-fuel ratio of hydrogen fuel (34.3:1), KnockLevel represents the knock level, represents the total air flow rate (measured by the MAF sensor), represents the hydrogen flow rate, the total air flow rate subtracts the air amount consumed by the equivalent hydrogen consumption (because it is lean burn, so there is still a part of the air amount left to burn ammonia). The remaining part of the air amount not participating in hydrogen combustion is used to correct the injection of the knock coefficient according to the air-fuel ratio.

[0051] Because ammonia is injected during knock, and ammonia itself is also a fuel that can burn and do work, so injecting ammonia will also cause an increase in the engine power. In order to maintain the torque stability, it is necessary to maintain the power when injecting ammonia, and it is necessary to synchronously reduce the injection of a part of hydrogen. The reduced amount needs to be corrected according to the calorific value of hydrogen, the calorific value of ammonia, the combustion efficiency of hydrogen, and the combustion efficiency of ammonia. Liquid ammonia is injected into the combustion chamber as a knock inhibitor, and at the same time, the hydrogen reduction injection amount is calculated according to the first calorific value conversion formula:

[0052] Q_H2 = Q_NH×(LHV_NH3×η_NH3) / (LHV_H2×η_H2)×K_adj;

[0053] Among them, LHV_NH3 (lower heating value of ammonia) = 18.6 MJ / kg, η_NH3 (combustion efficiency) = 0.42, LHV_H (lower heating value of hydrogen) = 120 MJ / kg, η_H2 (combustion efficiency) = 0.44, K_adj is the cylinder working condition correction coefficient (0.8 - 1.2), and the calculation method of the correction coefficient K_adj includes,

[0054] K_adj = 1 + 0.02×(T_comb - 850) + 0.015×(λ - 1.8);

[0055] Among them, T_comb is the instantaneous combustion temperature (°C), and λ is the excess air coefficient.

[0056] Establish a working condition parameter space and match it with historical knock data. Calibrate the knock working condition data including the speed, load, intake air temperature, and anti-knock value of the hydrogen internal combustion engine through the knock level. Input the knock working condition data into the working condition mapping database in the working condition parameter space for query. When there is the same working condition data as the knock working condition data in the working condition mapping database, preferentially call the ammonia injection quantity Q_saved of the adjacent working condition data in the mapping table, take the ammonia injection quantity Q_saved in the working condition data as the first target ammonia injection quantity, and take the first target ammonia injection quantity as the ammonia injection quantity reference value. Use the S-shaped curve gradient method to correct the injection parameters that do not cover the knock working condition data. Set up a query in the working condition mapping database to reduce the data query difficulty and improve the equipment working efficiency.

[0057] When there is no working condition data the same as the knock working condition data in the working condition mapping database, take the knock working condition data as the input of the rough learning model, the output of the fine learning model is the second target ammonia injection quantity, take the second target ammonia injection quantity as the ammonia injection quantity reference value, and when the knock working condition data meets the preset working condition validity condition, store both the knock working condition data and the second target ammonia injection quantity into the working condition mapping database.

[0058] Confirm the validity of the learning parameters through the working condition validity condition. The working condition validity condition is that the speed of the hydrogen internal combustion engine is less than the preset rated speed, the load of the hydrogen internal combustion engine is less than the preset rated load, the intake air temperature of the hydrogen internal combustion engine is less than the intake air temperature threshold of the hydrogen internal combustion engine, and the anti-knock value of the hydrogen internal combustion engine is less than the preset anti-knock threshold. By setting the working condition validity condition, screen the parameters to improve the rationality of the data.

[0059] As Figure 5 shown, when the hydrogen internal combustion engine has knock or pre-ignition, determine the knock level according to the real-time knock signal. Calibrate the knock level according to the vibration amplitude and phase of the real-time knock signal.

[0060] The ammonia injection amount base value is corrected according to the knock level to obtain the ammonia injection amount, and knock or pre-ignition is suppressed by the ammonia injection amount.

[0061] For L1 knock: Ammonia injection amount = Ammonia injection amount base value × (1 + preset knock level coefficient × (knock level - 1)). The ignition angle of the hydrogen internal combustion engine is retarded by the preset third crankshaft angle range × the preset speed correction coefficient. The preset knock level coefficient is (2-5)°CA for the third crankshaft angle range.

[0062] For L2 knock, the hydrogen injection pressure phase splitting of the hydrogen internal combustion engine is triggered. The hydrogen injection rate of the main nozzle of the hydrogen internal combustion engine is advanced by a preset fourth crankshaft angle phase, and the hydrogen injection rate of the rear nozzle of the hydrogen internal combustion engine is reduced to a preset first hydrogen injection rate. The fourth crankshaft angle is 2°CA, and the first hydrogen injection rate is reduced by 30% from the original hydrogen injection rate.

[0063] When the hydrogen internal combustion engine meets the continuous knock conditions, the continuous knock treatment measures and the SCR cooperative control measures are triggered to cooperatively suppress knock or pre-ignition.

[0064] The continuous knock condition includes setting a knock cycle. The continuous knock condition is setting a knock cycle. The pressure phase difference ΔP_ between adjacent cylinders of the hydrogen internal combustion engine in three consecutive knock cycles is 相邻缸 Both are greater than the preset phase difference threshold, which is 15%.

[0065] The continuous knock control measure involves activating the hydrogen engine's direct-injection ammonia barrier, setting the engine's injection pulse width to a preset standard value, and raising the engine's air-fuel ratio to the standard value. The standard injection pulse width is 1.5ms, and the standard air-fuel ratio lambda is 2.4. This achieves dual-functionality coupling between the knock suppressant and the SCR reductant, enabling system octane self-learning, preventing frequent initiation of knock protection, and extending the engine's service life.

[0066] like Figure 2 As shown, a hydrogen internal combustion engine knock suppression system, the system includes,

[0067] The liquid ammonia dual-channel supply module is used to output liquid ammonia; the liquid ammonia dual-channel supply module includes a liquid ammonia storage tank and an electronically controlled three-way valve. The liquid ammonia storage tank and the electronically controlled three-way valve are both installed on the vehicle body, and the outlet end of the liquid ammonia storage tank is connected to the inlet end of the electronically controlled three-way valve through a pipeline.

[0068] The first liquid ammonia branch: The first outlet end of the electronically controlled three-way valve is connected to the intake port injector of the hydrogen internal combustion engine through a pipeline. It is used for knock suppression; the electronically controlled three-way valve includes an anti-crystallization design: an integrated PTC ceramic heating element (operating voltage 12V, temperature control accuracy ±3°C), and an ultrasonic atomizer (frequency 1.7MHz) is set 50mm downstream of the injection port.

[0069] The second liquid ammonia branch: The second outlet end of the electronically controlled three-way valve is connected to the SCR injector of the hydrogen internal combustion engine through a pipeline. It is used for the reduction of NOx. The SCR injector of the hydrogen internal combustion engine is also connected to a liquid ammonia evaporator (electric heating temperature control ±2°C, gasification rate ≥99%).

[0070] The knock identification module is used to output real-time knock signals. The knock identification module is a knock sensor and a crankshaft sensor. The knock sensor is used to collect cylinder block vibration signals in the frequency band of 1 - 10kHz. The crankshaft sensor is used to define the pre-ignition window: 30°CA before top dead center to the ignition moment; define the knock window: 10°CA to 60°CA after ignition. Both the knock sensor and the crankshaft sensor are installed on the hydrogen internal combustion engine.

[0071] When knocking occurs in the hydrogen internal combustion engine, it is necessary to verify through the pressure phase difference of adjacent cylinders: set the knock period, and when the pressure phase difference ΔP_ of adjacent cylinders continuously exceeds 15% for three consecutive knock periods, an effective knock is confirmed.

[0072] The ECU applies the above-mentioned knock suppression method for a hydrogen internal combustion engine to control the liquid ammonia output according to the real-time knock signal to eliminate knock or pre-ignition.

[0073] As Figure 3 shown, the hydrogen internal combustion engine also includes a hydrogen fuel supply system: a high-pressure hydrogen storage tank, a hydrogen direct injection nozzle, and a hydrogen flow controller. A control actuator: an ammonia injection valve (response time ≤5ms, flow range 0.1 - 10kg / h), an electronic throttle for adjusting the intake air volume. An ignition module for dynamically adjusting the ignition angle.

[0074] The above are only the preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, without departing from the structure of the present invention, several deformations and improvements can be made, which will not affect the implementation effect of the present invention and the practicality of the patent.

Claims

1. A method for suppressing knocking in a hydrogen internal combustion engine, characterized in that, The method is as follows: obtain a real-time knock signal, and when the real-time knock signal meets a preset fault condition, determine that the hydrogen internal combustion engine has knocking or pre-ignition; when the hydrogen internal combustion engine has knocking or pre-ignition, calibrate the knock level according to the real-time knock signal, obtain a base ammonia injection amount according to the knock level, correct the base ammonia injection amount to obtain a target ammonia injection amount, and detect the knock cycle of the hydrogen internal combustion engine. When it is determined that the hydrogen internal combustion engine has knocking or pre-ignition within a continuous plurality of the knock cycles, a knock alarm is given.

2. The method for suppressing knocking in a hydrogen internal combustion engine according to claim 1, characterized in that, The method for correcting the base ammonia injection amount is as follows: When the knock level is L1, the target ammonia injection amount = base ammonia injection amount × (1 + preset knock level coefficient × (knock level - 1)), and the ignition angle of the hydrogen internal combustion engine is retarded by a preset third crank angle range × a preset engine speed correction coefficient; When the knock level is L2, the hydrogen injection pressure phase of the hydrogen internal combustion engine is segmented, the hydrogen injection amount of the main nozzle of the hydrogen internal combustion engine is advanced by a preset fourth crank angle phase, and the hydrogen injection amount of the after nozzle of the hydrogen internal combustion engine is reduced to a preset first hydrogen injection amount.

3. A method for suppressing knocking in a hydrogen internal combustion engine according to claim 1, characterized in that, The method for obtaining the base ammonia injection amount is as follows: Input the real-time knock signal into a preset working condition mapping database, and query whether there is an ammonia injection amount matching the real-time knock signal in the working condition mapping database. When there is an ammonia injection amount matching the real-time knock signal in the working condition mapping database, use the ammonia injection amount in the working condition mapping database as the base ammonia injection amount; When there is no ammonia injection amount matching the real-time knock signal in the working condition mapping database, calculate the base ammonia injection amount through the real-time knock signal and the working condition of the hydrogen internal combustion engine.

4. A method for suppressing knocking in a hydrogen internal combustion engine according to claim 3, characterized in that, The expression for calculating the base ammonia injection amount is: Among them, AFR NH3 represents the dynamically set value, K temp represents the temperature compensation coefficient, K temp represents the pressure compensation coefficient, AFR H2 represents the theoretical air-fuel ratio of hydrogen fuel, KnockLevel represents the knock level, represents the total air flow rate, represents the hydrogen flow rate.

5. A method for suppressing knocking in a hydrogen internal combustion engine according to claim 1, characterized in that, When the pressure phase difference ΔP_ between adjacent cylinders of the hydrogen internal combustion engine in multiple consecutive knocking cycles 相邻缸 is greater than the preset phase difference threshold, it is determined that knocking or pre-ignition occurs in the hydrogen internal combustion engine during multiple consecutive knocking cycles, and a continuous knocking treatment measure is triggered; The continuous knock treatment measure is to activate the in-cylinder direct injection ammonia curtain barrier of the hydrogen internal combustion engine, set the injection pulse width of the hydrogen internal combustion engine to be greater than or equal to a preset injection pulse width standard value, and increase the air-fuel ratio of the hydrogen internal combustion engine to an air-fuel ratio standard value.

6. A method for suppressing knocking in a hydrogen internal combustion engine according to claim 1, characterized in that, When the knock alarm is given, trigger the SCR collaborative control measure to jointly suppress knocking or pre-ignition. The SCR collaborative control measure is to obtain the NOx concentration and ammonia slip at the SCR inlet of the hydrogen internal combustion engine, and control the ammonia injection amount according to the NOx concentration and ammonia slip at the SCR inlet so that the conversion efficiency of the NOx concentration is greater than or equal to a preset conversion efficiency standard value and the ammonia slip is less than or equal to a preset ammonia slip threshold.

7. A method for suppressing knock in a hydrogen internal combustion engine according to claim 1, characterized in that, The fault conditions include a knock determination condition, a first pre-ignition determination condition, and a second pre-ignition determination condition; The knock determination condition is that the amplitude of the real-time knock signal is greater than a preset knock signal amplitude threshold and the phase of the real-time knock signal is within a preset first crank angle range after the ignition command; The first pre-ignition determination condition is that the abnormal cylinder pressure rise rate of the hydrogen internal combustion engine is greater than a preset cylinder pressure threshold and the phase of the real-time knock signal is greater than a preset second crank angle before the ignition command; The second pre-ignition determination condition is that the phase shift of the cylinder pressure PV value detected before the exhaust valve opens is greater than a preset phase shift threshold value and the combustion pressure gradient is greater than a preset combustion pressure gradient threshold value; When the knock determination condition is satisfied, it is determined that the hydrogen internal combustion engine has a knock; when both the first pre-ignition determination condition and the second pre-ignition determination condition are satisfied, it is determined that the hydrogen internal combustion engine has a pre-ignition.

8. A knock suppression system for a hydrogen internal combustion engine, characterized in that, The system includes, A liquid ammonia dual-channel supply module for outputting liquid ammonia; A knock identification module for outputting a real-time knock signal; An ECU that applies a hydrogen internal combustion engine knock suppression method according to any one of claims 1-7 above to control the liquid ammonia output according to the real-time knock signal to eliminate knock or pre-ignition.

9. A hydrogen internal combustion engine knock suppression system according to claim 8, characterized in that, The liquid ammonia dual-channel supply module includes a liquid ammonia storage tank and an electronically controlled three-way valve. The outlet end of the liquid ammonia storage tank is connected to the inlet end of the electronically controlled three-way valve through a pipeline. The first outlet end of the electronically controlled three-way valve is connected to the intake port injector of the hydrogen internal combustion engine through a pipeline as the first liquid nitrogen branch; the second outlet end of the electronically controlled three-way valve is connected to the SCR injector of the hydrogen internal combustion engine through a pipeline as the second liquid nitrogen branch.

10. A hydrogen internal combustion engine knock suppression system according to claim 8, characterized in that, The knock identification module is a knock sensor and a crankshaft sensor, and both the knock sensor and the crankshaft sensor are electrically connected to the ECU.

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