Liquid ammonia engine mechanism, control method and system

Abstract

The application relates to the engine technical field and provides a liquid ammonia engine structure, a control method and a system.The liquid ammonia engine structure comprises a liquid ammonia supply structure which is communicated with an inlet end of a high-pressure ammonia rail through a pipeline; the high-pressure ammonia rail is connected with a cooling structure, and liquid ammonia in the high-pressure ammonia rail is cooled through heat exchange with cooling liquid of the cooling structure; a liquid ammonia temperature sensor is further arranged on the high-pressure ammonia rail; an outlet end of the high-pressure ammonia rail is communicated with a high-pressure liquid ammonia nozzle through a pipeline; the high-pressure liquid ammonia nozzle atomizes high-pressure liquid ammonia into tiny liquid drops and then sprays the liquid drops into a combustion chamber; a cylinder pressure sensor is arranged at the top of the combustion chamber; an oxygen sensor is arranged on an exhaust pipeline; the system further comprises an ECU module; wherein the ECU module dynamically decides through a preset sub-working condition control strategy based on the running condition of the engine and the acquired monitoring data. The application solves the problem of actual injection amount reduction caused by liquid gas entrainment in the liquid ammonia conveying process.

Description

Technical Field

[0001] This application relates to the field of engine technology, and in particular to a liquid ammonia engine mechanism, control method and system. Background Technology

[0002] Vehicle emissions account for a significant portion of total transportation emissions, making the green transition of internal combustion engines a key focus. Energy conservation, emission reduction, and efficient energy utilization will remain themes for a long time to come. Ammonia, lacking carbon atoms and producing no carbon dioxide during combustion, boasts high energy density and is considered one of the most promising fuels for internal combustion engines. Furthermore, ammonia storage and transportation technologies are well-established, and it is typically stored in vehicles as liquid ammonia.

[0003] Ammonia liquefies at very low pressure, requiring only 1 MPa at room temperature (25°C). However, liquid ammonia is extremely unstable and easily vaporizes within storage containers and pipelines due to temperature and pressure fluctuations during engine operation, forming a liquid-gas mixture. This reduces the actual amount of ammonia injected into the cylinder, resulting in decreased engine power output. Data indicates that to ensure stable liquid ammonia delivery (without vaporization), the liquid ammonia temperature must not exceed 50°C at a pressure of 20 MPa.

[0004] The current solution to the injection volume control problem caused by liquid ammonia vaporization is to extract liquid ammonia from the high-pressure ammonia rail, vaporize it into high-pressure ammonia gas through heat exchange with the engine coolant, and then pressurize it in the ammonia tank. Although this method can maintain stable pressure in the ammonia tank, the high-temperature, high-pressure ammonia gas after heat exchange with the engine coolant will heat the liquid ammonia in the tank, which cannot effectively solve the problem of reduced actual injection volume caused by liquid-gas entrainment during liquid ammonia transportation. Summary of the Invention

[0005] The purpose of this invention is to provide a liquid ammonia engine mechanism, control method, and system to solve the problem of reduced actual injection volume caused by liquid-gas entrainment during liquid ammonia transportation, thereby ensuring stable liquid ammonia transportation. The specific solution is as follows:

[0006] A liquid ammonia engine mechanism, comprising:

[0007] The liquid ammonia supply structure is connected to the inlet end of the high-pressure ammonia rail via a pipeline;

[0008] The high-pressure ammonia rail is connected to the cooling structure, wherein the liquid ammonia inside the high-pressure ammonia rail is cooled by exchanging heat with the coolant in the cooling structure; a liquid ammonia temperature sensor for monitoring the temperature of the liquid ammonia inside the high-pressure ammonia rail is also arranged on the high-pressure ammonia rail.

[0009] The outlet end of the high-pressure ammonia rail is connected to the high-pressure liquid ammonia nozzle located at the top of the combustion chamber via a pipe;

[0010] The high-pressure liquid ammonia nozzle is used to atomize high-pressure liquid ammonia into tiny droplets and then spray them into the combustion chamber.

[0011] The combustion chamber is equipped with a cylinder pressure sensor at the top for monitoring the combustion state of the mixture inside the cylinder; the exhaust gas generated in the combustion chamber is discharged through an exhaust pipe, and an oxygen sensor is installed on the exhaust pipe for monitoring the excess air coefficient of the mixture inside the combustion chamber.

[0012] It also includes: ECU module;

[0013] The ECU module makes dynamic decisions based on the engine's operating conditions and acquired monitoring data, using a preset operating condition control strategy.

[0014] When liquid ammonia vaporization in the high-pressure ammonia rail is detected, causing liquid-gas entrainment, the actual liquid ammonia injection deviation is controlled within a preset range by adjusting the liquid ammonia injection pulse width and activating the ammonia rail cooling circuit, thereby stabilizing the engine's operating status.

[0015] Furthermore, the liquid ammonia supply structure includes:

[0016] A liquid ammonia tank; the liquid ammonia tank is connected in sequence to a liquid ammonia filter, a low-pressure liquid ammonia pump, a booster pump, and a high-pressure ammonia rail via pipelines; a low-pressure liquid ammonia pressure sensor is installed between the low-pressure liquid ammonia pump and the booster pump; a high-pressure liquid ammonia pressure sensor and a liquid ammonia flow meter are installed between the booster pump and the high-pressure ammonia rail; the low-pressure liquid ammonia pressure sensor, the liquid ammonia flow meter, and the high-pressure liquid ammonia pressure sensor are all connected to the ECU signal.

[0017] Furthermore, the cooling structure includes: an intake intercooling system and a control valve connected to the ECU signal; wherein, the ammonia cooling passage of the intake intercooling system is connected to the high-pressure ammonia rail through the control valve, and the liquid ammonia in the high-pressure ammonia rail is cooled by the coolant inside the ammonia cooling passage; the intake heat exchange passage inside the intercooling system is connected to the intake system and is used to heat the intake air entering the engine.

[0018] Furthermore, this includes the following steps:

[0019] S1: Acquire engine operating conditions and monitoring data; wherein the operating conditions include at least: medium and low load conditions, high load conditions, and acceleration conditions; the monitoring data includes at least: liquid ammonia temperature in the high-pressure ammonia rail, oxygen content in the exhaust gas, and cylinder pressure;

[0020] S2: Based on operating conditions and monitoring data, dynamic decisions are made through preset sub-condition control strategies; when liquid ammonia vaporization in the high-pressure ammonia rail is detected, causing liquid-gas entrainment, the actual liquid ammonia injection volume deviation is controlled within the preset range by adjusting the liquid ammonia injection pulse width and cooling strategy, so that the engine's operating status is stable.

[0021] Furthermore, step S2 specifically includes:

[0022] When the engine is determined to be operating under medium to low load conditions, the first oxygen content in the exhaust gas is obtained by monitoring the oxygen sensor.

[0023] When the first oxygen content is less than or equal to the preset oxygen content value, it is determined that no liquid ammonia vaporization has occurred in the high-pressure ammonia rail. At this time, the ECU controls the high-pressure liquid ammonia nozzle to maintain the original injection pulse width.

[0024] When the first oxygen content is greater than the preset oxygen content value, it is determined that liquid ammonia vaporization has occurred in the high-pressure ammonia rail, and the ECU generates the first control command at this time.

[0025] Based on the first control command, the acquired liquid ammonia temperature is compared with the preset liquid ammonia temperature range;

[0026] When the liquid ammonia temperature exceeds the upper limit of the preset liquid ammonia temperature range, a cooling strategy is triggered.

[0027] Based on the cooling strategy, the ECU opens the control valve and exchanges heat between the coolant of the intake intercooler system and the liquid ammonia in the high-pressure ammonia rail until the liquid ammonia temperature is ≤ the lower limit of the preset liquid ammonia temperature range. This stops the heat exchange, triggers the compensation strategy, and sets the current liquid ammonia temperature as the target liquid ammonia temperature.

[0028] Based on the compensation strategy, the first difference between the preset oxygen content value and the first oxygen content is obtained, and based on the first difference, the target liquid ammonia temperature, and the high-pressure ammonia rail pressure, the pre-calibrated mapping data is traversed to obtain the compensation injection pulse width.

[0029] The ECU controls the high-pressure liquid ammonia nozzle to inject based on the sum of the compensated injection pulse width and the original injection pulse width until the first oxygen content falls within the preset oxygen content range and the engine is running stably. Then, the compensation strategy is stopped and the original injection pulse width is restored.

[0030] Furthermore, step S2 also includes:

[0031] When the engine is determined to be under high load, the cylinder pressure is monitored by the cylinder pressure sensor.

[0032] The ECU calculates the average indicated pressure based on the in-cylinder pressure;

[0033] If the average indicated pressure is greater than or equal to the preset average indicated pressure, the ECU controls the high-pressure liquid ammonia nozzle to maintain the original injection pulse width.

[0034] If the average indicated pressure is less than the preset average indicated pressure, it is determined that liquid ammonia vaporization has occurred in the high-pressure ammonia rail, and the ECU generates a second control command at this time.

[0035] Based on the second control command, the acquired liquid ammonia temperature is compared with the preset liquid ammonia temperature range;

[0036] When the liquid ammonia temperature exceeds the upper limit of the preset liquid ammonia temperature range, a cooling strategy is triggered.

[0037] Based on the cooling strategy, the ECU opens the control valve and exchanges heat between the coolant of the intake intercooler system and the liquid ammonia in the high-pressure ammonia rail until the liquid ammonia temperature is ≤ the lower limit of the preset liquid ammonia temperature range, at which point the heat exchange stops and the compensation strategy is triggered.

[0038] Based on the compensation strategy, the first deviation between the preset average indicated pressure and the average indicated pressure is obtained, and the fuel compensation amount is obtained based on the correspondence between the average indicated pressure IMEP deviation and the fuel compensation amount.

[0039] Calculate the compensated injection pulse width based on the fuel compensation amount;

[0040] The ECU controls the high-pressure liquid ammonia nozzle to inject based on the sum of the compensated injection pulse width and the original injection pulse width until the average indicated pressure falls within the preset pressure range and the engine operates stably. Then, the compensation strategy is stopped and the original injection pulse width is restored.

[0041] Furthermore, step S2 also includes:

[0042] When the engine is determined to be in acceleration mode, the maximum burst pressure in the cylinder is monitored by the cylinder pressure sensor.

[0043] The ECU calculates the rate of change of the maximum burst pressure in the cylinder based on the in-cylinder pressure and the liquid ammonia temperature in the high-pressure ammonia rail.

[0044] If the rate of change of the maximum burst pressure is greater than or equal to the preset change value, the ECU controls the high-pressure liquid ammonia nozzle to maintain the original injection pulse width.

[0045] If the rate of change of the maximum burst pressure is less than the preset change value, it is determined that liquid ammonia vaporization has occurred in the high-pressure ammonia rail, and the ECU generates a third control command at this time.

[0046] Based on the third control command, the acquired liquid ammonia temperature is compared with the preset liquid ammonia temperature range;

[0047] When the liquid ammonia temperature exceeds the upper limit of the preset liquid ammonia temperature range, a cooling strategy is triggered.

[0048] Based on the cooling strategy, the ECU opens the control valve and exchanges heat between the coolant of the intake intercooler system and the liquid ammonia in the high-pressure ammonia rail until the liquid ammonia temperature is ≤ the lower limit of the preset liquid ammonia temperature range, at which point the heat exchange stops and the compensation strategy is triggered.

[0049] Based on the compensation strategy, the first deviation between the preset change value and the rate of change of the maximum burst pressure is obtained, and the fuel compensation amount is obtained based on the correspondence between the rate of change deviation and the fuel compensation amount.

[0050] Calculate the compensated injection pulse width based on the fuel compensation amount;

[0051] The ECU controls the high-pressure liquid ammonia nozzle to inject based on the sum of the compensated injection pulse width and the original injection pulse width until the rate of change falls within the preset deviation range and the engine operates stably. Then, the compensation strategy is stopped and the original injection pulse width is restored.

[0052] A liquid ammonia engine control system, the system comprising:

[0053] The monitoring module is configured to acquire the engine's operating conditions and monitoring data; wherein the operating conditions include at least: low and medium load conditions, high load conditions, and acceleration conditions; and the monitoring data includes at least: liquid ammonia temperature in the high-pressure ammonia rail, oxygen content in the exhaust gas, and cylinder pressure.

[0054] The strategy control module is configured to make dynamic decisions based on operating conditions and monitoring data through preset sub-condition control strategies. When liquid ammonia vaporization in the high-pressure ammonia rail is detected, resulting in liquid-gas entrainment, the actual liquid ammonia injection deviation is controlled within a preset range by adjusting the liquid ammonia injection pulse width and activating the ammonia rail cooling circuit, thereby stabilizing the engine's operating status.

[0055] An electronic device includes: a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other via the communication bus; characterized in that the memory stores a computer program, which, when executed by the processor, causes the processor to perform the steps of the method.

[0056] A computer-readable storage medium storing a computer program executable by an electronic device, which, when run on the electronic device, causes the electronic device to perform the steps of the method.

[0057] A simulation platform, comprising:

[0058] An electronic device for implementing the steps of the method;

[0059] A processor that runs a program, and when the program runs, it executes the steps of the method from data output by the electronic device.

[0060] A storage medium for storing a program that, when run, executes the steps of the method on data output from an electronic device.

[0061] The above solution achieves the following beneficial technical effects:

[0062] This application provides a liquid ammonia engine mechanism, control method, and system. By monitoring cylinder pressure and exhaust oxygen content, it determines whether liquid ammonia vaporization has occurred. By extending the liquid ammonia injection time, it compensates for the reduction in actual injection volume caused by liquid ammonia vaporization, thus restoring the engine to normal output. By monitoring the liquid ammonia temperature within the high-pressure ammonia rail and controlling the temperature within the rail using a cooling circuit, stable transportation is ensured, thereby avoiding the problem of reduced actual injection volume caused by liquid-gas entrainment during liquid ammonia transportation. Attached Figure Description

[0063] Figure 1 This is a schematic diagram of the overall structure of the liquid ammonia engine mechanism.

[0064] Figure 2 This is a flowchart illustrating the control method for a liquid ammonia engine.

[0065] Figures 3-5 This is a flowchart illustrating the control methods for a liquid ammonia engine under different operating conditions. Detailed Implementation

[0066] To make the purpose, technical solution, and advantages of this application clearer, the following will be described in conjunction with the appendix. Figures 1-5 This application will be described in further detail. It is obvious that the described embodiments are merely some, not all, of the embodiments described herein. All other embodiments obtained by those skilled in the art based on the embodiments described herein without inventive effort are within the scope of protection of this application.

[0067] It should be noted that any symbols and / or numbers present in the specification that are not marked in the accompanying drawings are not reference numerals.

[0068] Figure 1 The names of the accessories are as follows: 1-Liquid ammonia tank, 2-Liquid ammonia filter, 3-Low-pressure liquid ammonia pump, 4-Low-pressure liquid ammonia pressure sensor, 5-Boost pump, 6-High-pressure liquid ammonia pressure sensor, 7-Liquid ammonia flow meter, 8-Liquid ammonia temperature sensor, 9-High-pressure ammonia rail, 10-Control valve, 11-Intake intercooler system, 12-Exhaust gas turbocharger, 13-Air filter, 14-High-pressure liquid ammonia nozzle, 15-Cylinder pressure sensor, 16-Spark plug, 17-Oxygen sensor, 18-Combined air intake, 19-Engine.

[0069] like Figure 1 The liquid ammonia engine mechanism shown includes:

[0070] The liquid ammonia supply structure is connected to the inlet end of the high-pressure ammonia rail 9 via a pipeline;

[0071] The high-pressure ammonia rail 9 is connected to the cooling structure, wherein the liquid ammonia inside the high-pressure ammonia rail 9 is cooled by exchanging heat with the coolant of the cooling structure; the high-pressure ammonia rail 9 is also equipped with a liquid ammonia temperature sensor 8 for monitoring the temperature of the liquid ammonia inside the high-pressure ammonia rail.

[0072] The outlet end of the high-pressure ammonia rail 9 is connected to the high-pressure liquid ammonia nozzle 14 located at the top of the combustion chamber via a pipe;

[0073] The high-pressure liquid ammonia nozzle 14 is used to atomize high-pressure liquid ammonia into tiny droplets and then spray them into the combustion chamber.

[0074] The top of the combustion chamber is equipped with a cylinder pressure sensor 15 and a spark plug 16 for monitoring the combustion state of the mixture in the cylinder; the exhaust gas generated in the combustion chamber is discharged through an exhaust pipe, and an oxygen sensor 17 for monitoring the excess air coefficient of the mixture in the combustion chamber is installed on the exhaust pipe.

[0075] It also includes: ECU module;

[0076] The ECU module makes dynamic decisions based on the operating conditions of the engine 19 and the acquired monitoring data through a preset sub-condition control strategy.

[0077] When liquid ammonia vaporization in the high-pressure ammonia rail is detected, causing liquid-gas entrainment, the actual liquid ammonia injection volume deviation is controlled within a preset range by adjusting the liquid ammonia injection pulse width and cooling strategy, so that the engine can operate stably.

[0078] Furthermore, the liquid ammonia supply structure includes:

[0079] Liquid ammonia tank 1; the liquid ammonia tank 1 is connected in sequence to liquid ammonia filter 2, low-pressure liquid ammonia pump 3, booster pump 5 and high-pressure ammonia rail 9 via pipelines; wherein, a low-pressure liquid ammonia pressure sensor 4 is installed between low-pressure liquid ammonia pump 3 and booster pump 5; a high-pressure liquid ammonia pressure sensor 6 and liquid ammonia flow meter 7 are installed between booster pump and high-pressure ammonia rail 9; wherein, the low-pressure liquid ammonia pressure sensor, liquid ammonia flow meter and high-pressure liquid ammonia pressure sensor are all connected to the ECU signal;

[0080] Furthermore, the cooling structure includes: an intake intercooling system 11 and a control valve 10 connected to the ECU signal; wherein, the ammonia cooling passage of the intake intercooling system 10 is connected to the high-pressure ammonia rail through the control valve 10; the liquid ammonia in the high-pressure ammonia rail is cooled by the coolant inside the ammonia cooling passage; the intake heat exchange passage inside the intercooling system is connected to the intake system and is used to heat the intake air entering the engine.

[0081] The high-pressure ammonia rail is connected to the cooling structure. Due to the high temperature during engine operation, the liquid ammonia temperature inside the high-pressure ammonia rail is prone to exceeding the stable delivery temperature of 50℃ at 20 MPa. The coolant temperature of the engine intake cooling structure is usually around 40℃, which can be used to cool the liquid ammonia. When the liquid ammonia temperature inside the high-pressure ammonia rail is too high, control valve 10 is opened to guide the coolant to flow through the high-pressure ammonia rail to cool the liquid ammonia.

[0082] It is understood that the ECU provided in this application makes dynamic decisions based on monitoring the liquid ammonia temperature, cylinder pressure data, and exhaust oxygen content data of the high-pressure ammonia rail, and through a preset sub-condition control strategy. When liquid ammonia vaporization in the high-pressure ammonia rail is detected, resulting in liquid-gas entrainment, the actual liquid ammonia injection volume deviation is controlled within a preset range by adjusting the liquid ammonia injection pulse width and cooling strategy, so that the engine's operating state is stable and the output of liquid ammonia is stable, thus avoiding the problem of reduced actual injection volume caused by liquid-gas entrainment during liquid ammonia delivery.

[0083] Figure 2 As shown, this application provides a liquid ammonia engine control method, including the following steps:

[0084] S1: Acquire engine operating conditions and monitoring data; wherein the operating conditions include at least: medium and low load conditions, high load conditions, and acceleration conditions; the monitoring data includes at least: liquid ammonia temperature in the high-pressure ammonia rail, oxygen content in the exhaust gas, and cylinder pressure;

[0085] S2: Based on operating conditions and monitoring data, dynamic decisions are made through preset sub-condition control strategies; when liquid ammonia vaporization in the high-pressure ammonia rail is detected, causing liquid-gas entrainment, the actual liquid ammonia injection volume deviation is controlled within the preset range by adjusting the liquid ammonia injection pulse width and cooling strategy, so that the engine can operate stably.

[0086] See Figure 3 Step S2 specifically includes:

[0087] When the engine is determined to be operating under medium to low load conditions, the first oxygen content in the exhaust gas is obtained by monitoring the oxygen sensor.

[0088] When the first oxygen content is less than or equal to the preset oxygen content value, it is determined that no liquid ammonia vaporization has occurred in the high-pressure ammonia rail. At this time, the ECU controls the high-pressure liquid ammonia nozzle to maintain the original injection pulse width.

[0089] When the first oxygen content is greater than the preset oxygen content value, it is determined that liquid ammonia vaporization has occurred in the high-pressure ammonia rail, and the ECU generates the first control command at this time.

[0090] Based on the first control command, the acquired liquid ammonia temperature is compared with the preset liquid ammonia temperature range;

[0091] When the liquid ammonia temperature exceeds the upper limit of the preset liquid ammonia temperature range, a cooling strategy is triggered.

[0092] Based on the cooling strategy, the ECU opens the control valve and exchanges heat between the coolant of the intake intercooler system and the liquid ammonia in the high-pressure ammonia rail until the liquid ammonia temperature is ≤ the lower limit of the preset liquid ammonia temperature range. This stops the heat exchange, triggers the compensation strategy, and sets the current liquid ammonia temperature as the target liquid ammonia temperature.

[0093] Based on the compensation strategy, the first difference between the preset oxygen content value and the first oxygen content is obtained. Based on the first difference, the target liquid ammonia temperature, and the high-pressure ammonia rail pressure, the pre-calibrated mapping data (e.g., the mapping table of small and medium load-oxygen difference-temperature-pressure-compensation pulse width) is traversed to obtain the compensation injection pulse width.

[0094] The ECU controls the high-pressure liquid ammonia nozzle to inject based on the sum of the compensated injection pulse width and the original injection pulse width until the first oxygen content falls within the preset oxygen content range and the engine is running stably. Then, the compensation strategy is stopped and the original injection pulse width is restored.

[0095] When the engine speed is between 1000-2000 rpm, the accelerator pedal position (APP) is between 30%-50%, and the load rate is between 20%-60%, the engine is considered to be operating under medium to low load conditions.

[0096] It is understandable that when the engine is under low to medium load conditions, the operating temperature gradually increases, which may lead to excessively high liquid ammonia temperature in the ammonia rail causing vaporization. Furthermore, at this time, the engine operates relatively smoothly, and the requirement for response speed is lower; therefore, a combination of excess air coefficient and liquid ammonia temperature control can be used.

[0097] The oxygen content (L) in the exhaust gas is monitored by oxygen sensor 17. O2 The liquid ammonia temperature sensor 8 monitors the liquid ammonia temperature T within the ammonia rail. 氨 Uploaded to the ECU, showing the oxygen content (L) in the exhaust gas. O2 The oxygen content is compared with the preset oxygen content L; if the oxygen content in the exhaust is not higher than the set value, the original injection pulse width is maintained.

[0098] If the oxygen content in the exhaust is higher than the set value, it is determined that liquid ammonia vaporization has occurred, and a liquid-gas mixture exists in the pipeline. This reduces the actual amount of ammonia injected into the cylinder, increases the excess air coefficient in the cylinder, and decreases the engine power output. Furthermore, when the liquid ammonia temperature exceeds the upper limit of the preset liquid ammonia temperature range, a cooling strategy is triggered; the liquid ammonia temperature T in the high-pressure ammonia rail is lowered. 氨 With respect to the preset upper limit of liquid ammonia temperature T 设定1 For comparison, if the liquid ammonia temperature in the high-pressure ammonia rail is higher than the set value, then control valve 10 is opened to guide the coolant from the engine intake intercooler system through the ammonia rail, lowering the ammonia rail temperature until the liquid ammonia temperature in the ammonia rail reaches T. 氨Not higher than the preset lower limit T of liquid ammonia temperature 设定2 If the liquid ammonia temperature in the high-pressure ammonia rail is not higher than the set value, the ammonia rail cooling circuit will be closed. Then, a compensation strategy will be triggered to compensate for the liquid ammonia injection quantity by extending the liquid ammonia injection time until the engine returns to stable output.

[0099] When the engine is operating at a stable output, the following conditions must be met:

[0100] The fluctuation range of the target speed under medium and low loads is ≤ ±50 rpm;

[0101] The deviation between the output torque and the target torque is ≤ ±5%;

[0102] Exhaust oxygen content (L) O2 It falls within ±1% of the set value.

[0103] See the figure; step S2 further includes:

[0104] When the engine is determined to be under high load, the cylinder pressure is monitored by the cylinder pressure sensor.

[0105] The ECU calculates the average indicated pressure based on the in-cylinder pressure;

[0106] If the average indicated pressure is greater than or equal to the preset average indicated pressure, the ECU controls the high-pressure liquid ammonia nozzle to maintain the original injection pulse width.

[0107] If the average indicated pressure is less than the preset average indicated pressure, it is determined that liquid ammonia vaporization has occurred in the high-pressure ammonia rail, and the ECU generates a second control command at this time.

[0108] Based on the second control command, the acquired liquid ammonia temperature is compared with the preset liquid ammonia temperature range;

[0109] When the liquid ammonia temperature exceeds the upper limit of the preset liquid ammonia temperature range, a cooling strategy is triggered.

[0110] Based on the cooling strategy, the ECU opens the control valve and exchanges heat between the coolant of the intake intercooler system and the liquid ammonia in the high-pressure ammonia rail until the liquid ammonia temperature is ≤ the lower limit of the preset liquid ammonia temperature range, at which point the heat exchange stops and the compensation strategy is triggered.

[0111] Based on the compensation strategy, the first deviation between the preset average indicated pressure and the average indicated pressure is obtained, and the fuel compensation amount is obtained based on the correspondence between the average indicated pressure IMEP deviation and the fuel compensation amount.

[0112] Calculate the compensated injection pulse width based on the fuel compensation amount;

[0113] The ECU controls the high-pressure liquid ammonia nozzle to inject based on the sum of the compensated injection pulse width and the original injection pulse width until the average indicated pressure falls within the preset pressure range and the engine operates stably. At this point, the compensation strategy is stopped and the original injection pulse width is restored.

[0114] It is understandable that when the engine is under high load, it is required to output maximum power and has a high demand for response speed, so the Mean Indicated Pressure (IMEP) is used for regulation.

[0115] Specifically: cylinder pressure sensor 15 monitors the cylinder pressure P, and liquid ammonia temperature sensor 8 monitors the liquid ammonia temperature T in the ammonia rail. 氨 The data is uploaded to the ECU. The ECU calculates the Mean Indicated Pressure (IMEP) using cylinder pressure data and compares the measured IMEP with the preset Mean Indicated Pressure. If the Mean Indicated Pressure is not lower than the set value, the original injection pulse width is maintained. If the Mean Indicated Pressure is lower than the set value, it is determined that liquid ammonia vaporization has occurred, and a liquid-gas mixture exists in the pipeline. The actual amount of ammonia injected into the cylinder decreases, and the engine output power decreases. At this time, a second control command is generated. The ECU further determines the liquid ammonia temperature in the high-pressure ammonia rail. When the liquid ammonia temperature exceeds the upper limit of the preset liquid ammonia temperature range, a cooling strategy is triggered, reducing the liquid ammonia temperature T in the high-pressure ammonia rail. 氨 With respect to the preset upper limit of liquid ammonia temperature T 设定1 For comparison, if the liquid ammonia temperature in the high-pressure ammonia rail is higher than the set value, then control valve 10 is opened to guide the coolant from the engine intake intercooler system through the ammonia rail, lowering the ammonia rail temperature until the liquid ammonia temperature in the ammonia rail reaches T. 氨 Not higher than the preset lower limit T of liquid ammonia temperature 设定2 If the liquid ammonia temperature in the high-pressure ammonia rail is not higher than the set value, the ammonia rail cooling circuit will be closed. Then, a compensation strategy will be triggered to compensate for the liquid ammonia injection quantity by extending the liquid ammonia injection time until the engine restores stable power output.

[0116] See Figure 5 Step S2 further includes:

[0117] When the engine is determined to be in acceleration condition, the maximum burst pressure in the cylinder is monitored by the cylinder pressure sensor.

[0118] The ECU calculates the rate of change of the maximum burst pressure in the cylinder based on the in-cylinder pressure and the liquid ammonia temperature in the high-pressure ammonia rail.

[0119] If the rate of change of the maximum burst pressure is greater than or equal to the preset change value, the ECU controls the high-pressure liquid ammonia nozzle to maintain the original injection pulse width.

[0120] If the rate of change of the maximum burst pressure is less than the preset change value, it is determined that liquid ammonia vaporization has occurred in the high-pressure ammonia rail, and the ECU generates a third control command at this time.

[0121] Based on the third control command, the acquired liquid ammonia temperature is compared with the preset liquid ammonia temperature range;

[0122] When the liquid ammonia temperature exceeds the upper limit of the preset liquid ammonia temperature range, a cooling strategy is triggered.

[0123] Based on the cooling strategy, the ECU opens the control valve and exchanges heat between the coolant in the intake intercooler system and the liquid ammonia in the high-pressure ammonia rail until the liquid ammonia temperature is ≤ the lower limit of the preset liquid ammonia temperature range, at which point the heat exchange stops and the compensation strategy is triggered.

[0124] Based on the compensation strategy, the first deviation between the preset change value and the rate of change of the maximum burst pressure is obtained, and the fuel compensation amount is obtained based on the correspondence between the rate of change deviation and the fuel compensation amount.

[0125] Calculate the compensated injection pulse width based on the fuel compensation amount;

[0126] The ECU controls the high-pressure liquid ammonia nozzle to inject based on the sum of the compensated injection pulse width and the original injection pulse width until the rate of change falls within the preset deviation range and the engine operates stably. Then, the compensation strategy is stopped and the original injection pulse width is restored.

[0127] Furthermore, when the accelerator pedal opening rapidly jumps from a low opening range to a high opening range within a preset time and remains there for an extended period, the engine operating condition is determined to be an acceleration condition. For example, when the accelerator pedal opening rapidly jumps from a low opening range to a high opening range (e.g., >40%) within 30ms and the duration is >50ms, the engine operating condition is determined to be an acceleration condition.

[0128] Specifically, when the engine is accelerating, the injection quantity suddenly increases, the liquid ammonia flow rate increases, and pressure fluctuations can lead to an increased possibility of vaporization. To ensure smooth acceleration, a high response speed is required for the liquid ammonia injection quantity control, which utilizes the maximum in-cylinder combustion pressure P. max rate of change dP max / dt is used for regulation.

[0129] The maximum burst pressure P inside the cylinder is monitored by cylinder pressure sensor 15. max The liquid ammonia temperature sensor 8 monitors the liquid ammonia temperature T within the ammonia rail. 氨 The data is uploaded to the ECU. The ECU then calculates the maximum in-cylinder combustion pressure P using the cylinder pressure data. max rate of change dP max / dt, the rate of change dP max Compare / dt with the preset change value, if dP max If / dt is not lower than the set value, the original injection pulse width is maintained; if dP maxIf / dt is lower than the set value, it is determined that liquid ammonia vaporization has occurred, and a liquid-gas mixture exists in the pipeline. The actual amount of ammonia injected into the cylinder is reduced, and the engine acceleration response speed decreases. At this time, a third control command is generated. The liquid ammonia temperature in the high-pressure ammonia rail is further judged. If the liquid ammonia temperature is greater than the upper limit of the preset liquid ammonia temperature range, a cooling strategy is triggered. The liquid ammonia temperature Tammonia in the high-pressure ammonia rail is compared with the preset upper limit of liquid ammonia temperature Tset1. If the liquid ammonia temperature in the high-pressure ammonia rail is higher than the set value, the control valve 10 is opened to guide the coolant of the engine intake intercooler system to flow through the ammonia rail, reducing the ammonia rail temperature until the liquid ammonia temperature Tammonia in the ammonia rail is not higher than the preset lower limit of liquid ammonia temperature Tset2, and the ammonia rail cooling circuit is closed. If the liquid ammonia temperature in the high-pressure ammonia rail is not higher than the set value and the ammonia rail cooling circuit is closed, a compensation strategy is triggered to compensate for the liquid ammonia injection amount by extending the liquid ammonia injection time until the engine resumes stable acceleration.

[0130] When the engine resumes stable acceleration, the following conditions must be met:

[0131] dP max The deviation of / dt from the set value is ≤±5%;

[0132] The instantaneous rate of change of engine speed is ≤ ±100 rpm / ms;

[0133] T 氨 Stable at T 设定2 ≤T 氨 ≤T 设定1 The pressure fluctuation of the high-pressure ammonia rail is ≤ ±0.5MPa.

[0134] It is understood that this application determines whether liquid ammonia vaporization occurs by monitoring cylinder pressure and exhaust oxygen content. Under different operating conditions, different control strategies are used to compensate for the reduction in actual injection volume caused by liquid ammonia vaporization. By monitoring the liquid ammonia temperature in the high-pressure ammonia rail, the liquid ammonia temperature in the rail is controlled by the coolant in the engine intercooling system to ensure stable delivery.

[0135] It should be noted that before generating the first / second / third control command, the following steps are also included: monitoring whether the pressure of the high-pressure ammonia rail falls within the target pressure range and whether the nozzle status is abnormal; when the internal pressure of the high-pressure ammonia rail falls within the target pressure range and the nozzle status is normal, it is determined to be a liquid ammonia vaporization phenomenon.

[0136] Secondly, this application provides a liquid ammonia engine control system, the system comprising:

[0137] The monitoring module is configured to acquire the engine's operating conditions and monitoring data; wherein the operating conditions include at least: low and medium load conditions, high load conditions, and acceleration conditions; and the monitoring data includes at least: liquid ammonia temperature in the high-pressure ammonia rail, oxygen content in the exhaust gas, and cylinder pressure.

[0138] The strategy control module is configured to make dynamic decisions based on operating conditions and monitoring data through preset sub-condition control strategies. When liquid ammonia vaporization in the high-pressure ammonia rail is detected, resulting in liquid-gas entrainment, the actual liquid ammonia injection deviation is controlled within a preset range by adjusting the liquid ammonia injection pulse width and activating the ammonia rail cooling circuit, thereby stabilizing the engine's operating status.

[0139] It is worth noting that although this system only discloses the monitoring module and the strategy control module, it does not mean that this system is limited to the above-mentioned basic functional modules. On the contrary, what this invention intends to express is that, based on the above-mentioned basic functional modules, those skilled in the art can add one or more functional modules in combination with the existing technology to form an infinite number of embodiments or technical solutions. That is to say, this system is open rather than closed. It should not be assumed that the scope of protection of the claims of this invention is limited to the above-disclosed basic functional modules just because this embodiment only discloses a few basic functional modules.

[0140] On the other hand, this application provides an electronic device, including: a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other through the communication bus;

[0141] The memory stores a computer program that, when executed by a processor, causes the processor to perform the steps of the method.

[0142] On the other hand, this application provides a computer-readable storage medium having a computer program / instructions stored thereon, which, when executed by a processor, implement the steps of the method.

[0143] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties.

[0144] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments described above. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetically switched memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms. The databases involved in the embodiments provided in this application can include at least one of relational and non-relational databases. Non-relational databases can include blockchain-based distributed databases, etc., and are not limited thereto. The processors involved in the various embodiments provided in this application may be general-purpose processors, central processing units, graphics processors, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited thereto.

[0145] A simulation platform, comprising:

[0146] An electronic device for implementing the steps of the method;

[0147] A processor that runs a program, which, when running, executes the steps of the method claimed in the electronic device from data output by the program.

[0148] A storage medium for storing a program that, when run, executes the steps of the method on data output from an electronic device.

[0149] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0150] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A liquid ammonia engine mechanism, characterized in that, include: The liquid ammonia supply structure is connected to the inlet end of the high-pressure ammonia rail via a pipeline; The high-pressure ammonia rail is connected to the cooling structure, wherein the liquid ammonia inside the high-pressure ammonia rail is cooled by exchanging heat with the coolant in the cooling structure; a liquid ammonia temperature sensor for monitoring the temperature of the liquid ammonia inside the high-pressure ammonia rail is also arranged on the high-pressure ammonia rail. The outlet end of the high-pressure ammonia rail is connected to the high-pressure liquid ammonia nozzle located at the top of the combustion chamber via a pipe; The high-pressure liquid ammonia nozzle is used to atomize high-pressure liquid ammonia into tiny droplets and then spray them into the combustion chamber. The combustion chamber is equipped with a cylinder pressure sensor at the top for monitoring the combustion state of the mixture inside the cylinder; the exhaust gas generated in the combustion chamber is discharged through an exhaust pipe, and an oxygen sensor is installed on the exhaust pipe for monitoring the excess air coefficient of the mixture inside the combustion chamber. It also includes: ECU module; The ECU module makes dynamic decisions based on the engine's operating conditions and acquired monitoring data, using a preset operating condition control strategy. When liquid ammonia vaporization in the high-pressure ammonia rail is detected, causing liquid-gas entrainment, the actual liquid ammonia injection deviation is controlled within a preset range by adjusting the liquid ammonia injection pulse width and activating the ammonia rail cooling circuit, thereby stabilizing the engine's operating status. When the engine is under light to medium load conditions, the excess air coefficient and liquid ammonia temperature are used for control; when the engine is under high load conditions, the average indicated pressure is used for regulation; when the engine is under acceleration conditions, the rate of change of the maximum in-cylinder burst pressure is used for regulation.

2. The liquid ammonia engine mechanism according to claim 1, characterized in that, The liquid ammonia supply structure includes: A liquid ammonia tank; the liquid ammonia tank is connected in sequence to a liquid ammonia filter, a low-pressure liquid ammonia pump, a booster pump, and a high-pressure ammonia rail via pipelines; a low-pressure liquid ammonia pressure sensor is installed between the low-pressure liquid ammonia pump and the booster pump; a high-pressure liquid ammonia pressure sensor and a liquid ammonia flow meter are installed between the booster pump and the high-pressure ammonia rail; the low-pressure liquid ammonia pressure sensor, the liquid ammonia flow meter, and the high-pressure liquid ammonia pressure sensor are all connected to the ECU signal. Furthermore, the cooling structure includes: an intake intercooling system and a control valve connected to the ECU signal; wherein, the ammonia cooling passage of the intake intercooling system is connected to the high-pressure ammonia rail through the control valve, and the liquid ammonia in the high-pressure ammonia rail is cooled by the coolant inside the ammonia cooling passage; the intake heat exchange passage inside the intercooling system is connected to the intake system and is used to heat the intake air entering the engine.

3. A control method for a liquid ammonia engine, characterized in that, Applied to the liquid ammonia engine mechanism as described in claim 1 or 2; The liquid ammonia engine control method includes the following steps: S1: Acquire engine operating conditions and monitoring data; wherein the operating conditions include at least: medium and low load conditions, high load conditions, and acceleration conditions; the monitoring data includes at least: liquid ammonia temperature in the high-pressure ammonia rail, oxygen content in the exhaust gas, and cylinder pressure; S2: Based on operating conditions and monitoring data, dynamic decisions are made through preset sub-condition control strategies; when liquid ammonia vaporization in the high-pressure ammonia rail is detected, causing liquid-gas entrainment, the actual liquid ammonia injection volume deviation is controlled within the preset range by adjusting the liquid ammonia injection pulse width and cooling strategy, so that the engine's operating status is stable.

4. The method according to claim 3, characterized in that, Step S2 specifically includes: When the engine is determined to be operating under medium to low load conditions, the first oxygen content in the exhaust gas is obtained by monitoring the oxygen sensor. When the first oxygen content is less than or equal to the preset oxygen content value, it is determined that no liquid ammonia vaporization has occurred in the high-pressure ammonia rail. At this time, the ECU controls the high-pressure liquid ammonia nozzle to maintain the original injection pulse width. When the first oxygen content is greater than the preset oxygen content value, it is determined that liquid ammonia vaporization has occurred in the high-pressure ammonia rail, and the ECU generates the first control command at this time. Based on the first control command, the acquired liquid ammonia temperature is compared with the preset liquid ammonia temperature range; When the liquid ammonia temperature exceeds the preset upper limit of the liquid ammonia temperature range, a cooling strategy is triggered. Based on the cooling strategy, the ECU opens the control valve and exchanges heat between the coolant of the intake intercooler system and the liquid ammonia in the high-pressure ammonia rail until the liquid ammonia temperature is ≤ the lower limit of the preset liquid ammonia temperature range. Then the heat exchange stops, triggering the compensation strategy and setting the current liquid ammonia temperature as the target liquid ammonia temperature. Based on the compensation strategy, the first difference between the preset oxygen content value and the first oxygen content is obtained, and based on the first difference, the target liquid ammonia temperature, and the high-pressure ammonia rail pressure, the pre-calibrated mapping data is traversed to obtain the compensation injection pulse width. The ECU controls the high-pressure liquid ammonia nozzle to inject based on the sum of the compensated injection pulse width and the original injection pulse width until the first oxygen content falls within the preset oxygen content range and the engine is running stably. Then, the compensation strategy is stopped and the original injection pulse width is restored.

5. The method according to claim 3, characterized in that, Step S2 also includes: When the engine is determined to be under high load, the cylinder pressure is monitored by the cylinder pressure sensor. The ECU calculates the average indicated pressure based on the in-cylinder pressure; If the average indicated pressure is greater than or equal to the preset average indicated pressure, the ECU controls the high-pressure liquid ammonia nozzle to maintain the original injection pulse width. If the average indicated pressure is less than the preset average indicated pressure, it is determined that liquid ammonia vaporization has occurred in the high-pressure ammonia rail, and the ECU generates a second control command at this time. Based on the second control command, the acquired liquid ammonia temperature is compared with the preset liquid ammonia temperature range; When the liquid ammonia temperature exceeds the preset upper limit of the liquid ammonia temperature range, a cooling strategy is triggered. Based on the cooling strategy, the ECU opens the control valve and exchanges heat between the coolant of the intake intercooler system and the liquid ammonia in the high-pressure ammonia rail until the liquid ammonia temperature is ≤ the lower limit of the preset liquid ammonia temperature range, at which point the heat exchange stops and the compensation strategy is triggered. Based on the compensation strategy, the first deviation between the preset average indicated pressure and the average indicated pressure is obtained, and the fuel compensation amount is obtained based on the correspondence between the average indicated pressure deviation and the fuel compensation amount. Calculate the compensated injection pulse width based on the fuel compensation amount; The ECU controls the high-pressure liquid ammonia nozzle to inject based on the sum of the compensated injection pulse width and the original injection pulse width until the average indicated pressure falls within the preset pressure range and the engine operates stably. Then, the compensation strategy is stopped and the original injection pulse width is restored.

6. The method according to claim 3, characterized in that, Step S2 also includes: When the engine is determined to be in acceleration condition, the maximum burst pressure in the cylinder is monitored by the cylinder pressure sensor. The ECU calculates the rate of change of the maximum burst pressure in the cylinder based on the in-cylinder pressure and the liquid ammonia temperature in the high-pressure ammonia rail. If the rate of change of the maximum burst pressure is greater than or equal to the preset change value, the ECU controls the high-pressure liquid ammonia nozzle to maintain the original injection pulse width. If the rate of change of the maximum burst pressure is less than the preset change value, it is determined that liquid ammonia vaporization has occurred in the high-pressure ammonia rail, and the ECU generates a third control command at this time. Based on the third control command, the acquired liquid ammonia temperature is compared with the preset liquid ammonia temperature range; When the liquid ammonia temperature exceeds the preset upper limit of the liquid ammonia temperature range, a cooling strategy is triggered. Based on the cooling strategy, the ECU opens the control valve and exchanges heat between the coolant of the intake intercooler system and the liquid ammonia in the high-pressure ammonia rail until the liquid ammonia temperature is ≤ the lower limit of the preset liquid ammonia temperature range, at which point the heat exchange stops and the compensation strategy is triggered. Based on the compensation strategy, the first deviation between the preset change value and the rate of change of the maximum burst pressure is obtained, and the fuel compensation amount is obtained based on the correspondence between the rate of change deviation and the fuel compensation amount. Calculate the compensated injection pulse width based on the fuel compensation amount; The ECU controls the high-pressure liquid ammonia nozzle to inject based on the sum of the compensated injection pulse width and the original injection pulse width until the rate of change falls within the preset deviation range and the engine operates stably. Then, the compensation strategy is stopped and the original injection pulse width is restored.

7. A liquid ammonia engine control system, characterized in that, Applied to the liquid ammonia engine mechanism as described in claim 1 or 2; The system includes: The monitoring module is configured to acquire the engine's operating conditions and monitoring data; wherein the operating conditions include at least: low and medium load conditions, high load conditions, and acceleration conditions; and the monitoring data includes at least: liquid ammonia temperature in the high-pressure ammonia rail, oxygen content in the exhaust gas, and cylinder pressure. The strategy control module is configured to make dynamic decisions based on operating conditions and monitoring data through preset sub-condition control strategies. When liquid ammonia vaporization in the high-pressure ammonia rail is detected, resulting in liquid-gas entrainment, the actual liquid ammonia injection deviation is controlled within a preset range by adjusting the liquid ammonia injection pulse width and activating the ammonia rail cooling circuit, thereby stabilizing the engine's operating status.

8. An electronic device, comprising: The system comprises a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other via the communication bus; characterized in that the memory stores a computer program, which, when executed by the processor, causes the processor to perform the steps of the method described in any one of claims 3-6.

9. A computer-readable storage medium, characterized in that, The device stores a computer program executable by an electronic device, which, when run on the electronic device, causes the electronic device to perform the steps of the method as described in any one of claims 3-6.

10. A simulation platform, characterized in that, include: An electronic device for implementing the steps of the method according to any one of claims 3-6; A processor that runs a program, which, when running, performs the steps of the method according to any one of claims 3-6 from data output by an electronic device. A storage medium for storing a program that, when run, performs the steps of the method according to any one of claims 3-6 on data output from an electronic device.

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