A methanol control method for a marine methanol engine

Abstract

The application provides a methanol control method for a marine methanol engine. The method predicts the risk of methanol leakage by analyzing the methanol escape route and gives a prediction control scheme to solve the leakage safety problem of the methanol engine in the actual working process, ensure the stable and reliable work of the methanol engine at the best, and improve the thermal efficiency. The method comprises the following steps: obtaining engine state information, methanol injection amount change trend state, engine speed difference information and engine torque difference information; comprehensively determining the engine state information, the methanol injection amount change trend state, the engine speed difference information and the engine torque difference information, and outputting the engine methanol supply state; the engine methanol supply state comprises methanol no escape, methanol imminent escape and methanol serious escape; and the methanol injection amount is subjected to feedforward control according to the engine methanol supply state.

Description

Technical Field

[0001] This invention belongs to the field of engine control technology, specifically relating to a methanol control method for a marine methanol engine. Background Technology

[0002] Methanol fuel is increasingly widely used in the context of energy conservation and environmental protection. Marine engines have high power outputs and require large injection volumes of methanol, making precise control of the injection quantity and timing difficult. Methanol possesses advantages such as high oxygen content, high octane number, high latent heat of vaporization, fast combustion speed, and good anti-knock properties, making it one of the most promising alternative fuels for marine engines. Currently, there are three main methods for applying methanol fuel in diesel engines: direct blending, port injection, and direct injection. Due to the limited miscibility of diesel and methanol, direct blending leads to incomplete combustion, reducing engine performance and increasing emissions. Port injection, due to methanol's high latent heat of vaporization, lowers the intake temperature, causing incomplete combustion of the working fluid, reducing engine combustion efficiency, and increasing pollutant emissions. Direct injection ignites methanol by compressing a small amount of diesel fuel, using composite injection technology to achieve methanol / diesel in-cylinder mixing. The high temperature and pressure environment inside the cylinder promotes methanol atomization, minimizing incomplete combustion and achieving good fuel economy while reducing soot and NOx emissions.

[0003] Methanol is as toxic as gasoline, or even more so, and can cause serious health problems such as blindness, kidney failure, and even death. Skin contact or inhalation of low concentrations of methanol can cause discomfort, while ingestion or inhalation of high concentrations is extremely dangerous and can be life-threatening. The minimum dose for oral methanol poisoning is approximately 100 mg / kg (body weight), and ingestion of 0.3–1 g / kg (body weight) can be fatal. Methanol is colorless and has an alcoholic odor, making it easily mistaken for alcohol. Dangerous signs must be posted at methanol storage locations to warn people of the risks of direct contact or ingestion without proper personal protective equipment. Furthermore, methanol leaks pose a high risk of combustion and explosion (6.0%–36.5%) and environmental pollution. Methanol explodes upon contact with open flames, static electricity, or activation. Leaked liquid can enter sewers or water bodies, damaging aquatic ecosystems. Therefore, preventing methanol escape and leakage is a crucial practical issue that must be addressed first in the application of new low-carbon fuels; failure to do so will lead to serious subsequent problems and economic losses. In addition, methanol has a high latent heat of vaporization, which is 3.7 times that of gasoline. At 20°C, the mass evaporation rate of methanol fuel is only 1 / 4 that of gasoline. At the same time, the mass evaporation rate of methanol is greatly affected by temperature. At 7°C, the mass evaporation rate is only 1 / 6 that at 20°C. This causes difficulties in cold starting of methanol engines and frequent low-temperature misfires, which in turn leads to incomplete combustion in the cylinder of methanol engines, resulting in the emission of toxic and harmful substances such as methanol, formaldehyde, formic acid, hydrocarbons, and nitrogen oxides. Summary of the Invention

[0004] This invention proposes a methanol control method for marine methanol engines. By analyzing methanol escape routes and predicting methanol leakage risks, a predictive control scheme is provided to solve the leakage safety problem of methanol engines in actual operation, ensure that methanol engines operate stably and reliably at their optimal level, and improve thermal efficiency.

[0005] The technical solution of this application is as follows:

[0006] A method for controlling methanol in a marine methanol engine, comprising:

[0007] Acquire engine status information, alcohol injection quantity change trend, engine speed difference information, and engine torque difference information;

[0008] Based on a comprehensive assessment of engine status information, methanol injection quantity change trend, engine speed difference information, and engine torque difference information, the engine methanol supply status is output; the engine methanol supply status includes no methanol escape, methanol is about to escape, and methanol escapes severely.

[0009] Based on the methanol supply status of the engine, the methanol injection quantity is controlled by feedforward.

[0010] Preferably, the trend of the amount of alcohol injected is obtained through a multi-cycle dynamic observation window for the amount of alcohol injected; the multi-cycle dynamic observation window outputs the trend of the amount of alcohol injected as six states: rising transition, falling transition, free, stable, rising close to stable, and falling close to stable, based on the trend of the amount of alcohol injected within a fixed cycle.

[0011] Preferably, the engine status information includes four states: starting, running, emergency stop, and normal stop; the engine speed difference information is defined as the difference between the engine target speed and the actual speed, including five levels: large positive speed deviation, small positive speed deviation, zero, small negative speed deviation, and large negative speed deviation; the engine torque difference information is defined as the difference between the engine target torque and the actual torque, including five levels: large positive torque deviation, small positive torque deviation, zero, small negative torque deviation, and large negative torque deviation.

[0012] Preferably, the step of comprehensively determining and outputting the engine methanol supply status based on engine status information, methanol injection quantity change trend, engine speed difference information, and engine torque difference information specifically includes:

[0013] When the trend of methanol injection volume change is stable, the engine is running, the speed difference information is zero, and the torque difference information is zero, there is no escape of output methanol.

[0014] When the trend of methanol injection volume change is rising or rising close to stabilization, and the engine is in the starting or running state, and the speed difference information is a large positive speed deviation or a small positive speed deviation, and the torque difference information is a large positive torque deviation or a small positive torque deviation, methanol output will soon escape.

[0015] When the trend of methanol injection volume change is free, or the engine is in emergency shutdown state, or the speed difference information is a large negative speed deviation, or the torque difference information is a large negative torque deviation, the output methanol will seriously escape.

[0016] In other combinations, methanol will escape from the output.

[0017] Preferably, when the engine methanol supply status is such that methanol is about to escape, the feedforward control quantity is increased to correct the methanol injection quantity in advance; when the engine methanol supply status is such that methanol is seriously escaping, protective measures including methanol pipeline purging and exhaust gas treatment are triggered.

[0018] Preferably, when the trend of the amount of alcohol sprayed is in an upward transition state, a larger positive feedforward amount corresponds to it; when it is in an upward approaching stable state, a smaller positive feedforward amount corresponds to it; when it is in a downward transition state, a larger negative feedforward amount corresponds to it; and when it is in a downward approaching stable state, a smaller negative feedforward amount corresponds to it.

[0019] Preferably, the method further includes: performing feedback correction on the amount of alcohol injected after feedforward control to achieve closed-loop tracking control of the amount of alcohol injected.

[0020] Preferably, the method is applicable to methanol high-pressure direct injection engines, methanol low-pressure intake port injection engines, premixed engines with manifold injection, dual-fuel engines, diesel micro-ignition engines, or high-energy ignition methanol engines.

[0021] By comprehensively judging the trend of methanol injection quantity change (six types: rising transition, falling transition, free, stable, rising to near stability, falling to near stability) with engine status information (four types: starting, running, emergency stop, normal stop), speed difference information (five levels: large positive deviation, small positive deviation, close to zero, small negative deviation, large negative deviation), and torque difference information (five levels: large positive deviation, small positive deviation, close to zero, small negative deviation, large negative deviation), the system outputs three engine methanol supply states: no methanol escape, methanol escape risk alarm, or severe methanol escape. Feedforward control and feedback correction are then performed based on the judgment results. This scheme identifies methanol escape in advance through a dynamic observation window of the methanol injection quantity before it occurs. The trend of methanol injection quantity changes (e.g., rising transition indicates a continuous and rapid increase in methanol injection quantity, falling transition indicates a continuous and rapid decrease in methanol injection quantity, and free methanol injection quantity indicates unstable methanol injection quantity control) and combined with engine operating conditions and speed-torque deviations to comprehensively assess escape risk, the feedforward control quantity is increased to actively correct the methanol injection quantity at the risk alarm stage, thereby preventing preventive intervention before methanol escape worsens. This avoids the lag defect of traditional control methods that only passively respond after escape occurs. Therefore, it can effectively reduce methanol escape quantity and prevent methanol from leaking into the air and causing safety and environmental risks. At the same time, by optimizing the dynamic response characteristics of methanol injection quantity, the engine thermal efficiency is improved, significantly enhancing the safety, economy, and environmental friendliness of methanol engines. Attached Figure Description

[0022] Figure 1 A flowchart illustrating the methanol control method for marine methanol engines;

[0023] Figure 2 This is for determining the status of the dynamic alcohol spraying volume observation window. Detailed Implementation

[0024] Reference Figure 1 This application provides a method for controlling methanol in a marine methanol engine, comprising:

[0025] S101, acquire engine status information, alcohol injection quantity change trend status, engine speed difference information and engine torque difference information;

[0026] S102, based on the engine status information, the trend of methanol injection quantity change, the engine speed difference information, and the engine torque difference information, a comprehensive judgment is made, and the engine methanol supply status is output; the engine methanol supply status includes no methanol escape, methanol is about to escape, and methanol escapes severely.

[0027] S103, feedforward control of methanol injection quantity is performed according to the methanol supply status of the engine.

[0028] The process involves pre-analyzing methanol escape routes and categorizing them into three types based on methanol fuel characteristics and supply methods: A) poor methanol combustion atomization; B) unreasonable methanol supply control; and C) escape during exhaust. The output of the methanol escape route analysis is categorized into three levels: no methanol escape, methanol escape risk alarm, and severe methanol escape.

[0029] In step S101, the engine status information is directly acquired by the engine electronic control unit (ECU). The ECU comprehensively determines the current state of the engine by collecting signals from the crankshaft position sensor, ignition switch status, and stop button status, etc. In this embodiment, the engine status is divided into the following four types:

[0030] The starting state refers to the stage where the engine speed begins to rise from 0 after the ignition switch is turned on, but has not yet reached the idle speed. In this state, the engine cylinder temperature is low, and the high latent heat of vaporization of methanol can lead to poor fuel atomization, resulting in incomplete combustion and methanol escape.

[0031] Operating state refers to the normal working state where the engine speed has reached or exceeded the idle speed and there is no shutdown command. Operating state can be further subdivided into steady-state operating conditions and transitional operating conditions. Transitional operating conditions (such as acceleration, deceleration, loading, and unloading) are high-risk scenarios for methanol escape.

[0032] Emergency shutdown state refers to a special state in which the electronic control unit executes the emergency shutdown procedure after the emergency shutdown button is triggered. In this state, the methanol supply is suddenly interrupted, and unburned methanol may remain in the intake manifold, cylinders, or exhaust system, posing a high risk of methanol escape.

[0033] Normal shutdown refers to a state where, after a normal shutdown command is triggered, the electronic control unit first stops methanol injection according to a preset program, and then stops the engine after the system has completed purging. In this state, the risk of methanol escape is controllable.

[0034] The trend of alcohol injection volume changes is obtained through a multi-cycle alcohol injection volume dynamic observation window.

[0035] The specific method for obtaining the data is as follows: Using ten engine operating cycles as a set of observation windows, the electronic control unit records the actual amount of methanol injected into each cylinder within each operating cycle. After each operating cycle is completed, the observation window slides forward one cycle, always retaining the methanol injection data from the most recent ten cycles.

[0036] Let the single-cylinder alcohol injection amounts for the ten cycles within the observation window be Q1, Q2, ..., Q10, then the change in alcohol injection amount ΔQ within the window is defined as the difference between the maximum and minimum single-cylinder alcohol injection amounts within the window, i.e., ΔQ = Qmax - Qmin.

[0037] Combination Figure 2, according to the magnitude of ΔQ and the change direction of the alcohol injection amount within the observation window, the change trend state of the alcohol injection amount is determined as the following six types:

[0038] The first is the rising transition state. When ΔQ > 100mg, and for any i from 1 to 9 within the observation window, Q(i + 1) > Qi, it is determined as the rising transition state. This state indicates that the alcohol injection amount is continuously increasing rapidly.

[0039] The second is the falling transition state. When ΔQ > 100mg, and for any i from 1 to 9 within the observation window, Q(i + 1) < Qi, it is determined as the falling transition state. This state indicates that the alcohol injection amount is continuously decreasing rapidly.

[0040] The third is the free state. When ΔQ > 100mg, and the positive and negative deviations of the alcohol injection amount alternate within the observation window, it is determined as the free state. This state indicates that the control of the alcohol injection amount is unstable and fluctuates violently.

[0041] The fourth is the stable state. When ΔQ < 50mg, it is determined as the stable state. This state indicates that the alcohol injection amount remains stable within the observation window without obvious fluctuations.

[0042] The fifth is the rising approaching stable state. When 50mg ≤ ΔQ ≤ 100mg, and for any i from 1 to 9 within the observation window, Q(i + 1) ≥ Qi, it is determined as the rising approaching stable state. This state indicates that the alcohol injection amount is still increasing, but the growth rate has slowed down and is transitioning to the stable state.

[0043] The sixth is the falling approaching stable state. When 50mg ≤ ΔQ ≤ 100mg, and for any i from 1 to 9 within the observation window, Q(i + 1) ≤ Qi, it is determined as the falling approaching stable state. This state indicates that the alcohol injection amount is still decreasing, but the decrease rate has slowed down and is transitioning to the stable state.

[0044] The engine speed difference information is obtained by calculation of the electronic control unit. The electronic control unit acquires the actual engine speed in real time through the crankshaft position sensor, and at the same time determines the target speed according to the current working conditions (including throttle pedal position, cruise control setting, load demand, etc.).

[0045] The calculation formula for the speed difference is: Δn = n_target - n_actual, where n_target is the target speed and n_actual is the actual speed.

[0046] In this embodiment, the rated speed of the target model is 1000r / min. According to the magnitude of the speed difference Δn, it is divided into the following 5 gears:

[0047] The first gear is for large positive speed deviation, i.e., Δn > 100 r / min. This gear indicates that the actual speed is significantly lower than the target speed.

[0048] The second gear is for small positive speed deviation, i.e., 10 r / min < Δn ≤ 100 r / min. This gear indicates that the actual speed is lower than the target speed.

[0049] The third gear is the zero-speed gear, i.e., -10r / min≤Δn≤10r / min. This gear indicates that the actual speed is basically the same as the target speed.

[0050] The fourth gear is for small negative speed deviation, i.e., -100r / min ≤ Δn < -10r / min. This gear indicates that the actual speed is higher than the target speed.

[0051] The fifth gear is for large negative speed deviation, i.e., Δn < -100 r / min. This gear indicates that the actual speed is significantly higher than the target speed.

[0052] The engine torque difference information is calculated and obtained by the electronic control unit. The electronic control unit determines the target torque by collecting accelerator pedal position signals, load sensor signals, etc., and calculates the actual output torque by using parameters such as engine speed, fuel injection quantity, and intake air volume.

[0053] The formula for calculating the torque difference is: ΔT = T_target − T_actual, where T_target is the target torque and T_actual is the actual torque.

[0054] In this embodiment, the target model has a rated power of 1200kW and a rated torque of 11460Nm. Based on the torque difference ΔT, it is divided into the following five levels:

[0055] The first gear is the large positive torque deviation gear, i.e., ΔT>2000Nm. This gear indicates that the actual torque is significantly lower than the target torque.

[0056] The second gear is for small positive torque deviation, i.e., 500Nm < ΔT ≤ 2000Nm. This gear indicates that the actual torque is lower than the target torque.

[0057] The third gear is the zero torque gear, meaning -500Nm≤ΔT≤500Nm. This gear indicates that the actual torque is basically the same as the target torque.

[0058] The fourth gear is the small negative torque deviation gear, that is, -2000Nm≤ΔT<-500Nm. This gear indicates that the actual torque is higher than the target torque.

[0059] The fifth gear is the gear with a large negative torque deviation, i.e., ΔT < -2000 Nm. This gear indicates that the actual torque is significantly higher than the target torque.

[0060] In this embodiment of the application, the comprehensive judgment module outputs "no methanol escape" when the following four conditions are met simultaneously:

[0061] The first condition is that the trend of the amount of alcohol sprayed is in a stable state, that is, ΔQ < 50mg.

[0062] The second condition is that the engine is in a running state.

[0063] The third condition is that the speed difference information is that the third gear is close to zero, that is, -10r / min≤Δn≤10r / min.

[0064] The fourth condition is that the torque difference information is close to zero in the third gear, i.e., -500Nm≤ΔT≤500Nm.

[0065] Under these combined conditions, it is evident that the engine combustion is complete, the methanol supply is well matched with the engine demand, and there is no risk of methanol escape.

[0066] The comprehensive judgment module outputs "Methanol is seriously escaping" when any one of the following four conditions is met:

[0067] The first condition is that the trend of the amount of alcohol sprayed is in a free state.

[0068] The second condition is that the engine is in an emergency stop state.

[0069] The third condition is that the speed difference information is the fifth gear with a large negative deviation, i.e., Δn < -100 r / min.

[0070] The fourth condition is that the torque difference information is the fifth gear with a large negative deviation, i.e., ΔT < -2000Nm.

[0071] Under any of the above conditions, methanol escape has already occurred or is about to occur in large quantities, and immediate security measures are required.

[0072] Except for the above-mentioned combinations of no methanol escape and severe methanol escape, all other input combinations will output a methanol escape risk alarm.

[0073] Typical risk alarm scenarios include, but are not limited to, the following:

[0074] In scenario one, the trend of the amount of alcohol injected is either rising or rising and approaching stability. The engine status is either starting or running. The speed difference information is either gear 1 (Δn>100r / min) or gear 2 (10r / min<Δn≤100r / min). The torque difference information is either gear 1 (ΔT>2000Nm) or gear 2 (500Nm<ΔT≤2000Nm).

[0075] Scenario 2: The trend of the amount of alcohol injected is either decreasing or decreasing to near stability. The engine status is running. The speed difference information is level 4 (-100r / min≤Δn<-10r / min), and the torque difference information is level 4 (-2000Nm≤ΔT<-500Nm).

[0076] Scenario 3: The engine is in the starting state, the trend of the methanol injection quantity is stable or rising and close to stable, the speed difference information is level 1 (Δn>100r / min), and the torque difference information is level 1 (ΔT>2000Nm).

[0077] When a methanol escape risk alarm is output, the feedforward control quantity is automatically increased to correct the methanol injection quantity in advance, so as to prevent the methanol escape state from deteriorating into a serious escape.

[0078] In the event of severe methanol leakage, safety measures should be triggered immediately, including stopping methanol injection, starting pipeline purging, and activating the exhaust gas treatment device, to ensure that methanol does not leak into the air.

[0079] Predictive control of methanol can monitor and predict various states of a methanol engine during operation. It can not only predict and alarm methanol escape, but also improve the combustion effect of the methanol engine and optimize the overall performance of the methanol engine through control strategies.

[0080] After the comprehensive judgment module outputs the engine methanol supply status, the feedforward control module calculates the feedforward methanol injection amount based on the status.

[0081] Specifically, the electronic control unit first calculates the baseline methanol injection quantity Q_base based on the current operating conditions. Then, it determines the magnitude and direction of the feedforward control quantity ΔQ_ff based on the engine's methanol supply status, and superimposes ΔQ_ff with Q_base to generate the final feedforward methanol injection quantity Q_ff = Q_base + ΔQ_ff.

[0082] The rules for determining the feedforward control quantity ΔQ_ff are as follows:

[0083] When the output methanol escape risk alarm is triggered and the methanol injection rate is in an upward transition state, a larger positive feedforward amount is used, i.e., ΔQ_ff = +ΔQ_large.

[0084] When the output methanol escape risk alarm is triggered and the methanol injection rate shows an upward trend approaching stability, a smaller positive feedforward amount is used, i.e., ΔQ_ff = +ΔQ_small.

[0085] When the output methanol escape risk alarm is triggered and the methanol injection rate is in a downward transition state, a larger negative feedforward amount is used, i.e., ΔQ_ff = -ΔQ_large.

[0086] When the output methanol escape risk alarm is triggered and the methanol injection rate is decreasing and approaching stability, a smaller negative feedforward amount is used, i.e., ΔQ_ff = -ΔQ_small.

[0087] When there is no escape of methanol output, the feedforward control quantity is zero, i.e., ΔQ_ff=0.

[0088] When methanol escapes significantly, the system stops methanol injection, i.e., Q_ff=0.

[0089] Feedforward control of methanol quantity is based on the prediction of methanol escape to calculate the feedforward methanol injection quantity, ensuring a reasonable and moderate methanol supply while guaranteeing power performance. Feedback correction of the methanol injection quantity not only verifies the effectiveness of predictive control but also ensures the closed-loop tracking characteristic of the methanol injection quantity as the operating conditions change, thereby improving control accuracy.

[0090] Based on feedforward control, this embodiment of the invention further includes a feedback correction step to achieve closed-loop tracking control of the alcohol injection quantity. The specific implementation method is as follows: The electronic control unit acquires the actual alcohol injection quantity signal Q_actual in real time and calculates the deviation e = Q_target - Q_actual between the actual alcohol injection quantity and the target alcohol injection quantity Q_target. This deviation e is used as a feedback quantity to calculate the feedback correction quantity ΔQ_fb. This feedback correction quantity is then added to the feedforward alcohol injection quantity for the next control cycle to correct the final alcohol injection quantity command for the next cycle.

[0091] The methods described in this application embodiment can be applied to methanol high-pressure direct injection engines as well as premixed engines with methanol low-pressure intake manifold injection, and are compatible with dual-fuel, diesel micro-ignition, or high-energy ignition methanol engines.

[0092] Compared with the prior art, the method of the present invention has the following beneficial effects:

[0093] (1) It can improve the power of methanol fuel engines and ensure that the combustion in the cylinder achieves high thermal efficiency, while preventing methanol leakage caused by instantaneous lag.

[0094] (2) Methanol leakage prevention and control to improve the safety of new energy engine systems.

[0095] (3) Converting a classic diesel engine into a methanol fuel engine involves adding a methanol injection valve to the intake manifold or intake port, or changing the injector to a dual-pipe dual-nozzle type, or adding a methanol injector. The mechanical modifications are minor, and the control system only needs to be reprogrammed in the original system and the control strategy needs to be changed. The cost is low and the development cycle is short.

Claims

1. A method for controlling methanol in a marine methanol engine, characterized in that, include: Acquire engine status information, alcohol injection quantity change trend, engine speed difference information, and engine torque difference information; Based on the engine status information, the trend of methanol injection quantity change, the engine speed difference information, and the engine torque difference information, a comprehensive judgment is made to output the engine methanol supply status. The engine methanol supply status includes no methanol escape, methanol about to escape, and severe methanol escape; Based on the methanol supply status of the engine, the methanol injection quantity is fed forward controlled.

2. The methanol control method for a marine methanol engine according to claim 1, characterized in that, The trend of the amount of alcohol injected is obtained through a multi-cycle dynamic observation window for alcohol injection. The multi-cycle dynamic observation window outputs the trend of the amount of alcohol injected as six states: rising transition, falling transition, free, stable, rising close to stable, and falling close to stable, based on the trend of the amount of alcohol injected within a fixed cycle.

3. The methanol control method for a marine methanol engine according to claim 2, characterized in that, The engine status information includes four states: start-up, running, emergency stop, and normal stop; the engine speed difference information is defined as the difference between the engine target speed and the actual speed, including five levels: large positive speed deviation, small positive speed deviation, zero, small negative speed deviation, and large negative speed deviation; the engine torque difference information is defined as the difference between the engine target torque and the actual torque, including five levels: large positive torque deviation, small positive torque deviation, zero, small negative torque deviation, and large negative torque deviation.

4. The methanol control method for a marine methanol engine according to claim 3, characterized in that, The engine methanol supply status is output based on a comprehensive judgment of engine status information, methanol injection quantity change trend, engine speed difference information, and engine torque difference information, specifically including: When the trend of methanol injection volume change is stable, the engine is running, the speed difference information is zero, and the torque difference information is zero, there is no escape of output methanol. When the trend of methanol injection volume change is rising or rising close to stabilization, and the engine is in the starting or running state, and the speed difference information is a large positive speed deviation or a small positive speed deviation, and the torque difference information is a large positive torque deviation or a small positive torque deviation, methanol output will soon escape. When the trend of methanol injection volume change is free, or the engine is in emergency shutdown state, or the speed difference information is a large negative speed deviation, or the torque difference information is a large negative torque deviation, the output methanol will seriously escape. In other combinations, methanol will escape from the output.

5. The methanol control method for a marine methanol engine according to claim 4, characterized in that, When the engine's methanol supply status indicates that methanol is about to escape, the feedforward control quantity is increased to correct the methanol injection quantity in advance; when the engine's methanol supply status indicates severe methanol escape, protective measures including methanol pipeline purging and exhaust gas treatment are triggered.

6. The methanol control method for a marine methanol engine according to claim 2, characterized in that, When the trend of the amount of alcohol sprayed is in an upward transition state, it corresponds to a larger positive feedforward amount; when it is in an upward state approaching a stable state, it corresponds to a smaller positive feedforward amount; when it is in a downward transition state, it corresponds to a larger negative feedforward amount; when it is in a downward state approaching a stable state, it corresponds to a smaller negative feedforward amount.

7. The methanol control method for a marine methanol engine according to claim 1, characterized in that, The method further includes: performing feedback correction on the amount of alcohol injected after feedforward control to achieve closed-loop tracking control of the amount of alcohol injected.

8. The method for controlling methanol in a marine methanol engine according to any one of claims 1-7, characterized in that, The method is applicable to methanol high-pressure direct injection engines, methanol low-pressure intake port injection engines, premixed engines with manifold injection, dual-fuel engines, diesel micro-ignition engines, or high-energy ignition methanol engines.

Images