A fuel cut-off method, device and engine controller for a gas engine

Abstract

The application discloses a fuel cut-off exit method and device of a gas engine and an engine controller, and relates to the field of engines.The method comprises the following steps: monitoring the opening degree change rate of an accelerator pedal, determining that the driver has an acceleration intention in response to the opening degree change rate of the accelerator pedal being greater than zero, pre-judging that the fuel cut-off exit is about to be triggered, calculating a fuel cut-off exit risk level coefficient based on the current vehicle speed and the overall speed ratio of the vehicle, and executing fuel pre-injection control based on the fuel cut-off exit risk level coefficient before a fuel cut-off exit trigger signal is generated.The application pre-reserves a pre-adjustment time by monitoring the opening degree change rate of the accelerator pedal and pre-judging the acceleration intention of the driver; the fuel cut-off exit risk level coefficient is calculated in combination with the current vehicle speed and the overall speed ratio of the vehicle. Before the fuel cut-off exit trigger signal is generated, fuel pre-injection is actively implemented, the state of the intake port and the in-cylinder mixture is optimized in advance, so that the backfire of the intake pipe and the detonation of the exhaust pipe are effectively inhibited, the exhaust system is protected, and the instantaneous emission of the engine is reduced.

Description

Technical Field

[0001] This invention relates to the field of engine technology, and more specifically, to a method, apparatus, and engine controller for cutting off fuel supply to a gas engine. Background Technology

[0002] Currently, gas engines typically employ a fuel cut-off function to save fuel when the vehicle is coasting in gear. When the driver presses the accelerator pedal again, and the engine switches from the fuel cut-off state back to normal fuel supply, i.e., the moment the FSO (Fuel Shut Off) is deactivated and fuel supply is restored, the complex desorption process of fuel adsorbed on the inner wall of the intake manifold and the high gear coasting of the vehicle result in high engine drag speed and fast intake air velocity, which can easily cause the air-fuel mixture to become too rich momentarily.

[0003] In existing technologies, a fixed-time open-loop control strategy is typically used to restore fuel supply, with both the delay time and the fuel supply restoration strategy executed according to preset calibration parameters. However, this control method lacks the ability to dynamically perceive the real-time vehicle motion and exhaust status, and cannot predict the driver's intentions, resulting in inherent control lag. Furthermore, when the vehicle exits the fuel cut-off condition under high-risk conditions such as high-speed, low-gear downhill driving, restoring fuel supply solely according to a fixed time sequence cannot meet the special demands of high engine drag speeds and fast intake airflow, easily leading to an instantaneously rich air-fuel mixture, causing intake manifold backfire and exhaust pipe popping, damaging the exhaust system and increasing instantaneous emissions. Summary of the Invention

[0004] In view of this, the present invention discloses a fuel cut-off exit method, device and engine controller for a gas engine, so as to realize the fundamental transformation of the control strategy from passive response to active prevention, effectively avoid the first incomplete combustion at the moment of fuel supply restoration after fuel cut-off exit, thereby suppressing the intake manifold backfire and exhaust manifold backfire caused by instantaneously rich air-fuel mixture from the root, effectively protecting the safety of the exhaust system and reducing instantaneous engine emissions.

[0005] A method for cutting off fuel supply to a gas-fired engine includes:

[0006] The rate of change of accelerator pedal opening is monitored. If the rate of change of accelerator pedal opening is greater than zero, it is determined that the driver has the intention to accelerate and it is predicted that the accelerator pedal will be deactivated soon.

[0007] Calculate the risk level coefficient for fuel cut-off exit based on the current vehicle speed and the vehicle's overall speed ratio;

[0008] Based on the aforementioned fuel cut-off exit risk level coefficient, fuel pre-injection control is performed before the fuel cut-off exit trigger signal is generated.

[0009] Optionally, a risk level coefficient for fuel cut-off exit is calculated based on the current vehicle speed and the vehicle's overall speed ratio, including:

[0010] Obtain the current vehicle speed and the overall vehicle speed ratio;

[0011] Calculate the engine anti-drag speed based on the current vehicle speed and the vehicle's overall speed ratio;

[0012] Based on the engine anti-drag speed, speed danger level parameters, and engine rated speed, calculate the theoretical risk level coefficient;

[0013] The risk level coefficient for the fuel cut-off exit is determined based on the theoretical risk level coefficient.

[0014] Optionally, determining the fuel cut-off exit risk level coefficient based on the theoretical risk level coefficient includes:

[0015] The theoretical risk level coefficient is directly determined as the fuel shortage exit risk level coefficient;

[0016] or,

[0017] The theoretical risk level coefficient is corrected based on the exhaust manifold temperature to obtain the corrected risk level coefficient.

[0018] The revised risk level coefficient is determined as the risk level coefficient for oil supply interruption exit.

[0019] Optionally, the theoretical risk level coefficient is corrected based on the exhaust manifold temperature to obtain a corrected risk level coefficient, including:

[0020] To obtain the exhaust manifold temperature and the ignition point of the fuel used in the gas engine;

[0021] The theoretical risk level coefficient is corrected based on the ratio of the difference between the exhaust manifold temperature and the fuel ignition point to the fuel ignition point, resulting in the corrected risk level coefficient.

[0022] Optionally, based on the fuel cut-off exit risk level coefficient, fuel pre-injection control is performed before the fuel cut-off exit trigger signal is generated, including:

[0023] In response to the fuel cut-off exit risk level coefficient being in the low to medium risk range, fuel pre-injection is performed, and the amount of fuel pre-injection is less than the target injection amount;

[0024] In response to the fuel cut-off exit risk level coefficient being in the high-risk range, a phased fuel injection strategy is executed, where the risk level in the high-risk range is higher than that in the medium-low risk range.

[0025] Optionally, performing fuel pre-injection includes:

[0026] Determine the target injection quantity based on the current engine speed and intake air volume;

[0027] The percentage of injections with medium and low risk is calculated based on the fuel cut-off exit risk level coefficient, and the percentage of injections with medium and low risk decreases as the fuel cut-off exit risk level coefficient increases;

[0028] The product of the low-to-medium risk injection percentage and the target injection amount is used as the fuel pre-injection amount, and fuel pre-injection is performed before the fuel cut-off exit trigger signal is generated.

[0029] Optionally, the implementation of the staged fuel injection strategy includes:

[0030] Calculate the percentage of high-risk injections based on the aforementioned fuel cut-off exit risk level coefficient;

[0031] Before the fuel cut-off exit trigger signal is generated, the product of the high-risk injection percentage and the target injection amount is used as the injection amount for pre-injection, and pre-injection is performed to create a pre-injection atmosphere in the cylinder.

[0032] In response to the generation of the fuel cut-off exit trigger signal, after the combustion state in the cylinder tends to stabilize, the fuel injection quantity is gradually increased to the target injection quantity;

[0033] During the phased fuel injection strategy, the valve opening is adjusted in coordination to optimize the matching between the intake air volume and the phased fuel injection volume, thereby optimizing the combustion preparation state in the cylinder.

[0034] Optionally, the fuel injection quantity in the fuel pre-injection control is determined based on the product of the injection percentage and the target injection quantity, and the gas engine fuel cut-off exit method further includes:

[0035] Obtain the current exhaust oxygen content and the target exhaust oxygen content range;

[0036] In response to the current exhaust oxygen content being lower than a preset lower limit of the target exhaust oxygen content range, the oxygen content correction coefficient is increased to increase the injection percentage;

[0037] In response to the current exhaust oxygen content being higher than a preset upper limit of the target exhaust oxygen content range, the oxygen content correction factor is reduced to decrease the injection percentage.

[0038] A fuel cut-off device for a gas engine, comprising:

[0039] The monitoring unit is used to monitor the rate of change of the accelerator pedal opening. In response to the rate of change of the accelerator pedal opening being greater than zero, it determines that the driver has the intention to accelerate and predicts that the accelerator pedal will be deactivated soon.

[0040] The calculation unit is used to calculate the risk level coefficient of fuel cut-off exit based on the current vehicle speed and the vehicle's overall speed ratio;

[0041] The execution unit is used to perform fuel pre-injection control based on the fuel cut-off exit risk level coefficient before the fuel cut-off exit trigger signal is generated.

[0042] An engine controller, including a memory and a processor;

[0043] The memory is used to store at least one instruction;

[0044] The processor is used to execute the at least one instruction to implement the above-described gas engine fuel cut-off exit method.

[0045] As can be seen from the above technical solution, the present invention discloses a fuel cut-off exit method, device and engine controller for a gas engine. It monitors the rate of change of accelerator pedal opening, and in response to the rate of change of accelerator pedal opening being greater than zero, it determines that the driver has the intention to accelerate, predicts that fuel cut-off will be triggered, calculates the fuel cut-off exit risk level coefficient based on the current vehicle speed and the vehicle's overall speed ratio, and performs fuel pre-injection control based on the fuel cut-off exit risk level coefficient before the fuel cut-off exit trigger signal is generated. This invention monitors the rate of change in accelerator pedal opening to predict the driver's acceleration intention and obtain pre-adjustment time in advance. Simultaneously, it combines the current vehicle speed and the vehicle's overall speed ratio to quantify the risk level coefficient of fuel cut-off exit. Based on this risk level coefficient, it proactively executes fuel pre-injection control before the actual generation of the fuel cut-off trigger signal, optimizing the air-fuel mixture state in the intake manifold and cylinder in advance. This fundamentally shifts the control strategy from passive response to proactive prevention, effectively avoiding the first incomplete combustion at the moment of fuel supply resumption after fuel cut-off. This fundamentally suppresses intake manifold backfire and exhaust pipe popping problems caused by instantaneously rich air-fuel mixtures, effectively protecting the exhaust system and reducing instantaneous engine emissions. Attached Figure Description

[0046] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the published drawings without creative effort.

[0047] Figure 1 This is a flowchart of a gas engine fuel cut-off exit method disclosed in an embodiment of the present invention;

[0048] Figure 2 This is a schematic diagram of the structure of a gas engine fuel cut-off exit device disclosed in an embodiment of the present invention;

[0049] Figure 3 This is a schematic diagram of the structure of an engine controller disclosed in an embodiment of the present invention. Detailed Implementation

[0050] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0051] Explanation of relevant terms:

[0052] FSO: An energy-saving strategy of the engine electronic control system. When the vehicle is coasting in gear and the driver fully releases the accelerator pedal, the ECU (Electronic Control Unit) will temporarily cut off the supply of fuel to the cylinders to save fuel.

[0053] FSO disengagement: The process by which the engine switches from a fuel-cut-off state back to a normal fuel supply state when the driver presses the accelerator pedal again.

[0054] Backfire / explosion / afterburning: Specifically refers to the phenomenon where, at the moment the FSO exits, the mixture is too rich, resulting in incomplete combustion. Unburned methane and other combustible mixtures are ignited by high temperatures in the exhaust pipe or muffler, causing an explosive combustion accompanied by a loud noise.

[0055] Wideband Lambda Sensor: A sensor that can continuously and accurately measure the oxygen content (λ value) in the engine exhaust pipe. Its measurement range is wider than that of traditional on / off oxygen sensors, and it is a core component for achieving precise control of fuel injection quantity.

[0056] Pre-conditioning: One of the core concepts proposed in this invention refers to optimizing the air-fuel mixture in the intake manifold and cylinder in advance through methods such as micro-injection of fuel gas and micro-adjustment of valves in the very short time before the FSO is officially phased out, so as to create favorable conditions for subsequent main injection.

[0057] Fuel cut-off exit risk level coefficient R: This invention defines a parameter to quantify the backfire risk when the FSO exits. It is calculated based on real-time data such as speed, gear position, and exhaust temperature, and is used to guide the timing and intensity of pre-adjustment intervention.

[0058] This invention discloses a fuel cut-off exit method, device, and engine controller for a gas engine. By monitoring the rate of change in accelerator pedal opening, the method predicts the driver's acceleration intention and obtains pre-adjustment time in advance. Simultaneously, by combining the current vehicle speed and the vehicle's overall speed ratio, the method quantifies and calculates the fuel cut-off exit risk level coefficient. Based on this risk level coefficient, before the actual generation of the fuel cut-off trigger signal, the method proactively executes fuel pre-injection control to optimize the air-fuel mixture state in the intake manifold and cylinder in advance. This achieves a fundamental shift in control strategy from passive response to proactive prevention, effectively avoiding the first incomplete combustion at the moment of fuel supply resumption after fuel cut-off. This fundamentally suppresses intake manifold backfire and exhaust pipe backfiring caused by instantaneously rich air-fuel mixture, effectively protecting the exhaust system and reducing instantaneous engine emissions.

[0059] See Figure 1 The present invention discloses a flowchart of a fuel cut-off exit method for a gas engine, which includes the following steps:

[0060] Step S101: Monitor the rate of change of accelerator pedal opening. In response to the rate of change of accelerator pedal opening being greater than zero, determine that the driver has the intention to accelerate and predict that the accelerator pedal will be deactivated soon.

[0061] In this embodiment, the monitored accelerator pedal opening change rate dθ / dt refers to the slope of the accelerator pedal position signal changing over time, typically obtained by differentiating the voltage signal from the accelerator pedal position sensor or using a sliding window trend algorithm. This parameter reflects the "trend" of the driver's operation rather than its "state." This embodiment monitors this trend parameter, the accelerator pedal opening change rate. When dθ / dt > 0 is detected, it means the driver has just begun to depress the accelerator pedal. Although the absolute value of the accelerator pedal opening may not yet have reached the recovery threshold, the driver already has the intention to accelerate. This trend-based predictive logic precedes the "action," thus providing the control system with a pre-adjustment time window (e.g., 50 to 150 milliseconds in advance), allowing subsequent risk assessment and pre-adjustment actions to be performed before the fuel cut-off recovery signal is formally generated.

[0062] In practical applications, when the rate of change of the accelerator pedal opening is detected to be less than or equal to zero, the fuel cut-off function is determined to remain active. Specifically, when dθ / dt≤0, it is determined that the driver has not pressed the accelerator pedal or is releasing the accelerator pedal. At this time, the vehicle maintains the current coasting or deceleration state, the fuel cut-off function continues to be maintained, and the system does not trigger subsequent pre-adjustment logic, thereby avoiding false triggering caused by road bumps and other interferences, and ensuring the stability of control.

[0063] Step S102: Calculate the risk level coefficient for fuel cut-off exit based on the current vehicle speed and the vehicle's overall speed ratio.

[0064] This step is a quantitative assessment of the potential risks during the moment of fuel cut-off recovery. When a vehicle is coasting in gear and fuel is cut off, the engine is dragged backward by the wheels. At this time, there is a definite mechanical relationship between engine speed, vehicle speed, gearbox gear ratio, and rear axle final drive ratio. The higher the vehicle speed and the higher the gear (the lower the gear ratio), the higher the engine speed dragged backward, and the faster the intake airflow. A fast intake airflow makes it difficult for fuel or air-fuel mixture to evaporate and atomize in the intake manifold. Furthermore, at the moment of fuel supply restoration, the high-speed airflow easily disperses the fuel jet, causing an uneven or momentarily rich air-fuel mixture, leading to backfire or explosion risks.

[0065] Therefore, this embodiment introduces a fuel cut-off exit risk level coefficient R, based on the current vehicle speed. and vehicle overall speed ratio The engine's reverse drag speed is calculated, and the risk level coefficient R for fuel cut-off exit is obtained. This quantitative assessment can identify whether the current operating condition is safe or high-risk, thus providing a basis for subsequent differentiated control.

[0066] Step S103: Based on the fuel cut-off exit risk level coefficient, perform fuel pre-injection control before the fuel cut-off exit trigger signal is generated.

[0067] The control logic of existing technology usually starts to execute the fuel supply action only after the fuel cut-off recovery trigger signal (i.e., the throttle opening reaches the threshold) is generated. If the target amount of fuel is injected directly at this time, an overly rich mixture is easily formed on the inner wall of the intake manifold.

[0068] In this embodiment, before the fuel cut-off trigger signal is generated, a pre-adjustment time window is obtained in step S101. Based on the fuel cut-off risk level coefficient calculated in step S102, fuel pre-injection is performed in advance. For example, when it is anticipated that the driver intends to accelerate but has not yet fully depressed the accelerator, the system injects a small amount of fuel to create a "preparatory" combustion atmosphere in the intake manifold and cylinder. When the driver actually depresses the accelerator and generates the fuel cut-off trigger signal, since the cylinder already has a suitable air-fuel mixture, the system only needs to inject the remaining fuel, thereby avoiding the problem of an overly rich mixture at the moment of recovery and effectively suppressing backfiring. This "prevention" control logic significantly improves the robustness and smoothness of engine control compared to the "post-compensation" of existing technologies.

[0069] In summary, this invention discloses a method for fuel cut-off exiting a gas engine. It monitors the rate of change of the accelerator pedal opening; when the rate of change of the accelerator pedal opening is greater than zero, it determines that the driver intends to accelerate, predicts that fuel cut-off will be triggered, calculates a fuel cut-off exit risk level coefficient based on the current vehicle speed and the vehicle's overall speed ratio, and performs fuel pre-injection control before the fuel cut-off trigger signal is generated. This invention predicts the driver's acceleration intention by monitoring the rate of change of the accelerator pedal opening, thus obtaining pre-adjustment time in advance. Simultaneously, it quantitatively calculates the fuel cut-off exit risk level coefficient by combining the current vehicle speed and the vehicle's overall speed ratio, and proactively performs fuel pre-injection control before the actual generation of the fuel cut-off trigger signal. This optimizes the air-fuel mixture state in the intake manifold and cylinder in advance, achieving a fundamental shift in control strategy from passive response to proactive prevention. It effectively avoids the first incomplete combustion at the moment of fuel supply resumption after fuel cut-off, thereby fundamentally suppressing intake manifold backfire and exhaust pipe popping problems caused by instantaneously rich air-fuel mixtures, effectively protecting the exhaust system and reducing instantaneous engine emissions.

[0070] In one embodiment, step S102 may specifically include:

[0071] (1) Obtain the current vehicle speed and the overall vehicle speed ratio.

[0072] Vehicle overall speed ratio Based on the gear ratio of the gearbox and the transmission ratio of the rear axle main reducer Confirmed. Specifically, the gear ratio of the gearbox. The rear axle final drive ratio can be obtained from the transmission controller via the CAN (Controller Area Network) bus or measured directly via the gear position sensor. These are typically fixed parameters at the vehicle's factory and pre-stored in the controller's calibration data. It should be understood that the vehicle's overall gear ratio reflects the amplification effect of the vehicle's transmission system on engine speed. The gear ratios differ significantly between different gears, directly affecting the engine's drag speed.

[0073] (2) Calculate the engine anti-drag speed based on the current vehicle speed and the vehicle's overall speed ratio.

[0074] When the vehicle is coasting in gear and the fuel supply is cut off, the engine is dragged and rotated by the wheels. At this time, the engine's reverse rotation speed is... With current vehicle speed There is a definite mechanical transmission relationship.

[0075] Current speed Vehicle overall speed ratio and engine reverse drag speed The following relations exist:

[0076] ;

[0077] The engine reverse drag speed is obtained by transforming the formula. The expression:

[0078] ;

[0079] In the formula, n represents the engine reverse drag speed, in revolutions per minute (rpm).

[0080] This indicates the current vehicle speed, in kilometers per hour (km / h).

[0081] r represents the tire rolling radius, measured in meters (m).

[0082] This embodiment calculates the engine's reverse drag speed. This quantifies the impact of vehicle motion on the intake process. The physical principle is that the higher the current vehicle speed and the lower the overall vehicle speed ratio, the higher the engine's reverse drag speed, which in turn leads to a faster intake airflow. Excessive intake airflow speed can shorten the atomization and evaporation time after fuel injection, and the high-speed airflow can easily disperse the fuel jet, causing uneven air-fuel mixture or instantaneous over-rich mixture, thereby increasing the risk of backfire or popping.

[0083] (3) Calculate the theoretical risk level coefficient based on the engine anti-drag speed, speed danger level parameter and engine rated speed.

[0084] The expression for the theoretical risk level coefficient is as follows:

[0085]

[0086] In the formula, This represents the theoretical risk level coefficient;

[0087] Indicates the engine's rated speed;

[0088] The parameter representing the degree of danger of the rotational speed is obtained through testing;

[0089] This represents the correction constant.

[0090] (4) Determine the oil cut-off exit risk level coefficient based on the theoretical risk level coefficient.

[0091] Specifically, in practical applications, the theoretical risk level coefficient can be... It is directly determined as the final risk level coefficient R for the oil supply cut-off exit.

[0092] In one embodiment, the theoretical risk level coefficient can be corrected based on the exhaust manifold temperature to obtain a corrected risk level coefficient; the corrected risk level coefficient is then determined as the fuel cut-off exit risk level coefficient.

[0093] In practical applications, to further improve the accuracy of risk assessment and adapt to different engine thermal states, the fuel cut-off exit risk level coefficient adopts a modified risk level coefficient, which is obtained by correcting the theoretical risk level coefficient for exhaust manifold temperature.

[0094] The process of correcting the theoretical risk level coefficient based on the exhaust manifold temperature to obtain the corrected risk level coefficient may specifically include:

[0095] To obtain the exhaust manifold temperature and the ignition point of the fuel used in the gas engine;

[0096] The theoretical risk level coefficient is corrected based on the ratio of the difference between the exhaust manifold temperature and the fuel ignition point to the fuel ignition point, resulting in the corrected risk level coefficient.

[0097] The revised expression for the risk level coefficient is as follows:

[0098]

[0099] Right now,

[0100]

[0101] In the formula, Indicates the exhaust manifold temperature;

[0102] This indicates the ignition point of the fuel used in the gas engine.

[0103] The physical significance of the exhaust manifold temperature correction theoretical risk level coefficient introduced in this embodiment is that the higher the exhaust manifold temperature, the more dangerous the thermal state of the exhaust system, and the higher the probability of backfire due to the unburned mixture entering the high-temperature exhaust pipe and being ignited. Especially when the exhaust manifold temperature approaches or even exceeds the fuel ignition point, the risk of backfire increases dramatically and non-linearly. This correction mechanism considers not only the vehicle's motion state (vehicle speed and gear) but also the engine's exhaust thermal state (exhaust manifold temperature), thus providing a precise quantitative basis for subsequent differentiated pre-adjustment strategies. It should be understood that the fuel ignition point can be adaptively adjusted according to the actual fuel type used by the engine (such as natural gas, liquefied petroleum gas, etc.) and stored in the controller's calibration data.

[0104] In one embodiment, step S103 may specifically include:

[0105] (1) In response to the fuel cut-off exit risk level coefficient being in the low to medium risk range, fuel pre-injection is performed, wherein the fuel pre-injection amount is less than the target injection amount.

[0106] When the calculated fuel cut-off risk level coefficient R is in the low-to-medium risk range (e.g., 2 ≤ R < 5), it indicates that the current engine drag speed is moderate, the disturbance of the air-fuel mixture caused by the intake airflow velocity is within a controllable range, and the exhaust manifold temperature has not reached the critical point where it is easily ignited. At this time, the system actively performs fuel pre-injection within the pre-adjustment time window before the fuel cut-off trigger signal is generated. The injection amount of this pre-injection is set to be less than the target injection amount, for example, set to 80% to 90% of the target injection amount. The reason why this embodiment adopts the "less than" strategy, rather than directly injecting the target amount or a very small amount, is that, on the one hand, pre-injecting a certain amount of fuel can pre-wet the intake manifold, promote the desorption process of fuel adsorbed on the inner wall of the intake manifold, establish a preliminary combustion atmosphere for the subsequent main injection, and avoid the mixture being too lean at the moment of recovery; on the other hand, retaining a certain injection margin (i.e., not reaching 100% of the target injection amount) is to prevent the mixture from being too rich at the moment of pre-injection due to fluctuations in the intake airflow velocity or sensor accuracy errors, thereby taking into account both the engine's power responsiveness and smoothness. It should be understood that the specific injection ratio can be calibrated according to the engine model and operating conditions, and is not limited to the above-mentioned numerical range.

[0107] (2) In response to the fuel cut-off exit risk level coefficient being in the high-risk range, a phased fuel injection strategy is executed, wherein the risk corresponding to the high-risk range is higher than that of the medium-low risk range.

[0108] When the calculated fuel cut-off risk level coefficient R is in the high-risk range (e.g., R≥5), it means that the engine reverse drag speed is high, the intake airflow velocity is fast, or the exhaust manifold temperature is high. If an injection strategy with a fuel cut-off risk level coefficient in the medium-low risk range is still used under these conditions, it is very easy for the fuel jet to be blown away by the intake airflow, resulting in wet walls, or for backfire to occur due to the high-temperature environment. Therefore, this embodiment adopts a staged fuel injection strategy, breaking down the fuel injection process into multiple stages to avoid the impact of "one-step" injection.

[0109] In one embodiment, in response to the fuel cut-off exit risk level coefficient being in the low to medium risk range, the process of performing fuel pre-injection may specifically include:

[0110] (1) Determine the target injection quantity based on the current engine speed and intake volume.

[0111] Based on the current engine speed and intake air volume, the target injection quantity under the current operating conditions is obtained by querying the basic MAP table, which is the control data table within the MCU. Target spray volume That is, the normal jet volume corresponding to the normal exit of fuel cut-off when there is no pre-adjustment.

[0112] (2) Calculate the low-to-medium risk injection percentage based on the fuel cut-off exit risk level coefficient, wherein the low-to-medium risk injection percentage decreases as the fuel cut-off exit risk level coefficient increases.

[0113] The injection percentage is not a fixed value, but is based on the current fuel cut-off risk level coefficient. The interval in question is calculated in real time.

[0114] When the risk level coefficient for exiting fuel cutoff is in the low to medium risk range, that is... ≤ < Percentage of low-to-medium risk sprays The calculation formula is as follows:

[0115]

[0116] In the formula, This indicates the lower limit of the risk range. This indicates the upper limit of the risk range. This represents the oxygen content correction factor.

[0117] by =2, Taking 5 as an example, when 2≤ When the risk level coefficient for oil supply interruption is less than 5, the risk level coefficient for exiting the oil supply interruption is determined. Located in the low to medium risk range, low to medium risk spray percentage The calculation formula is as follows:

[0118]

[0119] In practical applications, It is usually between 50% and 90%.

[0120] (3) The product of the low-to-medium risk injection percentage and the target injection amount is used as the injection amount for fuel pre-injection, and fuel pre-injection is performed before the fuel cut-off exit trigger signal is generated.

[0121] In this embodiment, when the fuel cut-off risk level coefficient is in the low to medium risk range, a pre-adjustment strategy is actively executed during the period before the accelerator pedal opening θ reaches the target accelerator pedal opening corresponding to the fuel cut-off exit. That is, fuel pre-injection is performed before the fuel cut-off trigger signal is generated. At this time, the system will reduce the amount of fuel enrichment, that is, inject slightly less fuel than under normal operating conditions. The amount of fuel pre-injection... The expression is as follows:

[0122] = ·

[0123] In the formula, This indicates the target injection quantity, which is the normal injection quantity corresponding to the normal exit from fuel cut-off without pre-adjustment.

[0124] In one embodiment, when the fuel shortage exit risk level coefficient Less than the lower limit of the risk range If it is determined that there is no risk of fuel cut-off and shutdown at this time, normal fuel injection operation will be performed directly.

[0125] In one embodiment, the process of implementing a staged fuel injection strategy includes:

[0126] (1) Calculate the percentage of high-risk injections based on the risk level coefficient of fuel cut-off exit.

[0127] When the risk level coefficient for exiting fuel cutoff is in the high-risk range, that is... ≥ High-risk spray percentage The calculation formula is as follows:

[0128]

[0129] by For example, when =5, When the risk level coefficient for fuel cut-off is ≥5, the risk level coefficient for exiting fuel cut-off is determined. Located in a high-risk zone, high-risk spray percentage The calculation formula is as follows:

[0130]

[0131] In practical applications, It usually ranges from 10% to 50%.

[0132] (2) Before the fuel cut-off exit trigger signal is generated, the product of the high-risk injection percentage and the target injection amount is used as the injection amount for the pre-injection, and the pre-injection is performed to create a pre-injection atmosphere in the cylinder.

[0133] (3) In response to the generation of the fuel cut-off exit trigger signal, after the combustion state in the cylinder tends to stabilize, the fuel injection quantity is gradually increased to the target injection quantity.

[0134] (4) During the phased fuel injection strategy, the valve opening is adjusted in coordination to optimize the matching of intake volume and phased fuel injection volume, thereby optimizing the combustion preparation state in the cylinder.

[0135] This embodiment employs a phased fuel injection strategy. First, a preparatory injection is performed with a high-risk injection percentage to create a preparatory combustion atmosphere. Then, the injection is gradually increased to the target value. At the same time, the valve opening is finely adjusted to optimize the matching of intake and injection. This ensures the smoothness of the recovery process from both temporal and spatial dimensions, completely avoiding backfiring in the exhaust pipe under high-risk conditions.

[0136] In actual application conditions, the electronic throttle is briefly and slightly closed just before the fuel cut-off ends. By reducing the intake air volume through intake throttling, the mixture at the initial moment of fuel injection is made leaner instantaneously while the fuel injection volume remains unchanged, thereby avoiding an overly rich mixture.

[0137] The phased fuel injection strategy involves a pre-injection phase before the fuel cut-off trigger signal is generated. The pre-injection quantity is a preset percentage of the target injection quantity. Specifically, this preset percentage is typically set relatively small, for example, 10% to 50% of the target injection quantity. A small amount of fuel is injected into the cylinder to create a "preparatory" lean combustion atmosphere. Due to the small injection quantity, even under high-velocity airflow, the fuel can be well atomized and mixed, avoiding the formation of large fuel droplets or overly rich areas. Subsequently, in response to the fuel cut-off trigger signal, the fuel injection quantity is gradually increased to the target injection quantity. Specifically, when the driver actually depresses the accelerator pedal, and the accelerator opening reaches the fuel cut-off threshold, after the formal fuel cut-off trigger signal is generated, the system no longer maintains the small pre-injection quantity but gradually increases the fuel injection quantity according to a preset slope or step curve until the target injection quantity required for the current operating condition is reached. This layered strategy of "preparatory injection + gradual increase" prolongs the fuel recovery process in terms of time, giving the formation of the mixture a buffer period, effectively avoiding an overly rich mixture at the moment of recovery, thereby suppressing backfiring in the exhaust pipe.

[0138] In one embodiment, the fuel injection quantity in fuel pre-injection control is determined based on the product of the injection percentage and the target injection quantity, and the gas engine fuel cut-off exit method further includes:

[0139] (1) Obtain the current exhaust oxygen content and the target exhaust oxygen content range.

[0140] Obtain the current exhaust oxygen content λ_real and the target exhaust oxygen content λ_target from the wide-range oxygen sensor feedback, and obtain the target exhaust oxygen content range λ_target by looking up a table. ),in, This is the preset lower limit value for the target exhaust oxygen content range. The preset upper limit for the target exhaust oxygen content range.

[0141] (2) In response to the current exhaust oxygen content being lower than the preset lower limit of the target exhaust oxygen content range, the oxygen content correction coefficient is increased to increase the injection percentage, thereby increasing the fuel injection quantity.

[0142] If λ_real < If the current exhaust oxygen content λ_real is determined to be too lean compared to the target exhaust oxygen content range, then the oxygen content correction coefficient is increased. ,For example, =5% to increase the injection percentage, thereby increasing the amount of fuel injected.

[0143] (3) In response to the current exhaust oxygen content being higher than the preset upper limit of the target exhaust oxygen content range, the oxygen content correction coefficient is reduced to reduce the injection percentage, thereby reducing the fuel injection amount.

[0144] If λ_real > If the current exhaust oxygen content λ_real is determined to be too rich compared to the target exhaust oxygen content range, then the oxygen content correction coefficient is increased. ,For example, =-5% to reduce the injection percentage, thereby reducing the amount of fuel injected.

[0145] It should be noted that when the fuel cut-off exit risk level coefficient is in the low to medium risk range, the injection percentage in this embodiment is the low to medium risk injection percentage; when the fuel cut-off exit risk level coefficient is in the high risk range, the injection percentage in this embodiment is the high risk injection percentage.

[0146] This invention introduces exhaust oxygen content as a feedback signal and uses an oxygen content correction coefficient to perform closed-loop correction of the injection percentage, establishing a transmission chain of "oxygen content correction coefficient → injection percentage → fuel injection quantity". It corrects the control accuracy in real time from the perspective of stoichiometry, effectively overcoming the disturbances caused by component aging and environmental changes, and ensuring the robustness of the system throughout its entire life cycle.

[0147] It should be noted that this invention can be applied to systems where pre-injection of fuel is not feasible or inconvenient, and can use a delayed ignition timing angle as a pre-adjustment control method. By delaying the ignition timing, some fuel continues to burn during the exhaust stroke, actively increasing the exhaust temperature and promoting the gradual oxidation of unburned hydrocarbons generated subsequently in the exhaust pipe, thereby avoiding detonation and backfiring.

[0148] The various combined control methods of pre-injection control, ignition control and throttle control involved in this invention can be flexibly selected and adapted according to the system hardware configuration and cost design requirements.

[0149] In summary, this invention constructs a three-level hierarchical control architecture of "prediction-pre-adjustment-feedback correction". The core key points are: 1) For the first time, the vehicle's operating state (vehicle speed, gear) and exhaust thermal state (exhaust manifold temperature) are integrated and coupled to establish a fuel cut-off exit risk level coefficient. 1) A quantitative assessment model is used to predict the risks of fuel cut-off exit conditions in advance; 2) A pre-adjustment control window is set before the fuel cut-off exit condition, and the traditional post-compensation control mode is transformed into a pre-prevention control mode through active intervention methods such as micro-injection; 3) A dual hardware closed-loop control loop is formed by an exhaust manifold temperature sensor and a wide-range oxygen sensor, which corrects the control quantity in real time from the thermodynamic dimension and the air-fuel ratio stoichiometric dimension, respectively, to improve control accuracy.

[0150] This invention possesses the following technical advantages: It completely eliminates the factors that induce exhaust backfiring at the source through a three-tiered protection mechanism; and it utilizes a fuel cut-off exit risk level coefficient. This enables the system to intelligently identify complex operating conditions of heavy vehicles and achieve precise control based on these conditions. The dual hardware closed-loop feedback mechanism ensures the robustness of the system throughout its entire lifecycle, unaffected by component aging or changes in environmental conditions. Simultaneously, the built-in fault diagnosis function effectively protects the engine and exhaust aftertreatment system, further enhancing the overall vehicle reliability.

[0151] Corresponding to the above method embodiments, the present invention also discloses a fuel cut-off exit device for a gas engine.

[0152] See Figure 2 The present invention discloses a schematic diagram of a fuel cut-off disconnection device for a gas engine, the device comprising:

[0153] The monitoring unit 201 is used to monitor the rate of change of the accelerator pedal opening. In response to the rate of change of the accelerator pedal opening being greater than zero, it determines that the driver has the intention to accelerate and predicts that the accelerator pedal will be deactivated soon.

[0154] In this embodiment, the monitored accelerator pedal opening change rate dθ / dt refers to the slope of the accelerator pedal position signal changing over time, typically obtained by differentiating the voltage signal from the accelerator pedal position sensor or using a sliding window trend algorithm. This parameter reflects the "trend" of the driver's operation rather than its "state." This embodiment monitors this trend parameter, the accelerator pedal opening change rate. When dθ / dt > 0 is detected, it means the driver has just begun to depress the accelerator pedal. Although the absolute value of the accelerator pedal opening may not yet have reached the recovery threshold, the driver already has the intention to accelerate. This trend-based predictive logic precedes the "action," thus providing the control system with a pre-adjustment time window (e.g., 50 to 150 milliseconds in advance), allowing subsequent risk assessment and pre-adjustment actions to be performed before the fuel cut-off recovery signal is formally generated.

[0155] The calculation unit 202 is used to calculate the risk level coefficient of fuel cut-off exit based on the current vehicle speed and the vehicle's overall speed ratio.

[0156] When a vehicle is coasting in gear and the fuel supply is cut off, the engine is dragged backward by the wheels. At this time, there is a definite mechanical relationship between the engine speed, vehicle speed, gearbox gear ratio, and rear axle final drive ratio. The higher the vehicle speed and the higher the gear (the lower the gear ratio), the higher the engine speed dragged backward, and the faster the intake airflow. A fast intake airflow makes it difficult for fuel or air-fuel mixtures to evaporate and atomize in the intake manifold. Furthermore, at the moment fuel supply is restored, the high-speed airflow easily disperses the fuel jet, causing an uneven or momentarily rich air-fuel mixture, leading to backfire or explosion risks.

[0157] Therefore, this embodiment introduces a fuel cut-off exit risk level coefficient R, based on the current vehicle speed. and vehicle overall speed ratio The engine's reverse drag speed is calculated, and the risk level coefficient R for fuel cut-off exit is obtained. This quantitative assessment can identify whether the current operating condition is safe or high-risk, thus providing a basis for subsequent differentiated control.

[0158] The execution unit 203 is used to perform fuel pre-injection control based on the fuel cut-off exit risk level coefficient before the fuel cut-off exit trigger signal is generated.

[0159] In this embodiment, before the fuel cut-off exit trigger signal is generated, the monitoring unit 201 obtains the pre-adjustment time window and performs fuel pre-injection in advance based on the fuel cut-off exit risk level coefficient calculated by the calculation unit 202.

[0160] In summary, this invention discloses a fuel cut-off exit device for a gas engine. It monitors the rate of change of the accelerator pedal opening. When the rate of change of the accelerator pedal opening is greater than zero, it determines that the driver intends to accelerate and predicts that fuel cut-off is about to be triggered. Based on the current vehicle speed and the vehicle's overall speed ratio, it calculates a fuel cut-off exit risk level coefficient. Based on this risk level coefficient, it performs fuel pre-injection control before the fuel cut-off trigger signal is generated. This invention predicts the driver's acceleration intention by monitoring the rate of change of the accelerator pedal opening, thus obtaining pre-adjustment time in advance. Simultaneously, it quantitatively calculates the fuel cut-off exit risk level coefficient by combining the current vehicle speed and the vehicle's overall speed ratio. Based on this risk level coefficient, it proactively performs fuel pre-injection control before the actual generation of the fuel cut-off trigger signal, optimizing the air-fuel mixture state in the intake manifold and cylinder in advance. This achieves a fundamental shift in control strategy from passive response to proactive prevention, effectively avoiding the first incomplete combustion at the moment of fuel supply resumption after fuel cut-off. This fundamentally suppresses intake manifold backfire and exhaust pipe popping problems caused by instantaneously rich air-fuel mixtures, effectively protecting the exhaust system and reducing instantaneous engine emissions.

[0161] In one embodiment, the computing unit 202 can be specifically used for:

[0162] Obtain the current vehicle speed and the overall vehicle speed ratio;

[0163] Calculate the engine anti-drag speed based on the current vehicle speed and the vehicle's overall speed ratio;

[0164] Based on the engine anti-drag speed, speed danger level parameters, and engine rated speed, calculate the theoretical risk level coefficient;

[0165] The risk level coefficient for the fuel cut-off exit is determined based on the theoretical risk level coefficient.

[0166] In one embodiment, the computing unit 202 can also be used for:

[0167] The theoretical risk level coefficient is directly determined as the fuel shortage exit risk level coefficient;

[0168] or,

[0169] The theoretical risk level coefficient is corrected based on the exhaust manifold temperature to obtain the corrected risk level coefficient.

[0170] The revised risk level coefficient is determined as the risk level coefficient for oil supply interruption exit.

[0171] In one embodiment, the computing unit 202 can also be used for:

[0172] To obtain the exhaust manifold temperature and the ignition point of the fuel used in the gas engine;

[0173] The theoretical risk level coefficient is corrected based on the ratio of the difference between the exhaust manifold temperature and the fuel ignition point to the fuel ignition point, resulting in the corrected risk level coefficient.

[0174] In one embodiment, the execution unit 203 may specifically be used for:

[0175] In response to the fuel cut-off exit risk level coefficient being in the low to medium risk range, fuel pre-injection is performed, and the amount of fuel pre-injection is less than the target injection amount;

[0176] In response to the fuel cut-off exit risk level coefficient being in the high-risk range, a phased fuel injection strategy is executed, where the risk level in the high-risk range is higher than that in the medium-low risk range.

[0177] In one embodiment, the execution unit 203 may specifically be used for:

[0178] Determine the target injection quantity based on the current engine speed and intake air volume;

[0179] The percentage of injections with medium and low risk is calculated based on the fuel cut-off exit risk level coefficient, and the percentage of injections with medium and low risk decreases as the fuel cut-off exit risk level coefficient increases;

[0180] The product of the low-to-medium risk injection percentage and the target injection amount is used as the fuel pre-injection amount, and fuel pre-injection is performed before the fuel cut-off exit trigger signal is generated.

[0181] In one embodiment, the execution unit 203 may specifically be used for:

[0182] Calculate the percentage of high-risk injections based on the aforementioned fuel cut-off exit risk level coefficient;

[0183] Before the fuel cut-off exit trigger signal is generated, the product of the high-risk injection percentage and the target injection amount is used as the injection amount for pre-injection, and pre-injection is performed to create a pre-injection atmosphere in the cylinder.

[0184] In response to the generation of the fuel cut-off exit trigger signal, after the combustion state in the cylinder tends to stabilize, the fuel injection quantity is gradually increased to the target injection quantity;

[0185] During the phased fuel injection strategy, the valve opening is adjusted in coordination to optimize the matching between the intake air volume and the phased fuel injection volume, thereby optimizing the combustion preparation state in the cylinder.

[0186] The fuel injection quantity in the fuel pre-injection control is determined based on the product of the injection percentage and the target injection quantity. The gas engine fuel cut-off device also includes:

[0187] The acquisition unit is used to acquire the current exhaust oxygen content and the target exhaust oxygen content range.

[0188] An increased injection quantity unit is used to increase the oxygen content correction coefficient to increase the injection percentage in response to the current exhaust oxygen content being lower than a preset lower limit value of the target exhaust oxygen content range;

[0189] The injection quantity reduction unit is used to reduce the oxygen content correction coefficient to reduce the injection percentage in response to the current exhaust oxygen content being higher than a preset upper limit of the target exhaust oxygen content range.

[0190] It should be noted that for the specific working principles of each component in the device embodiment, please refer to the corresponding section of the method embodiment, which will not be repeated here.

[0191] Corresponding to the above embodiments, the present invention provides a computer storage medium that stores at least one instruction, which, when executed by a processor, implements the steps shown in the embodiments of the gas engine fuel cut-off exit method.

[0192] Computer storage media can be tangible media that may contain or store programs for use by or in conjunction with an instruction execution system, apparatus, or device. Computer storage media can be machine-readable signal media or machine-readable storage media. Computer storage media can be, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0193] Corresponding to the above embodiments, such as Figure 3 As shown, the present invention also provides a schematic diagram of the structure of an engine controller, which may include: a processor 1 and a memory 2;

[0194] The processor 1 and memory 2 communicate with each other via communication bus 3.

[0195] Processor 1, for executing at least one instruction;

[0196] Memory 2 is used to store at least one instruction;

[0197] Processor 1 may be a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to implement embodiments of the present invention.

[0198] Memory 2 may include high-speed RAM memory, and may also include non-volatile memory, such as at least one disk storage device.

[0199] In this embodiment, the processor executes at least one instruction to implement the steps shown in the gas engine fuel cut-off exit method.

[0200] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0201] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0202] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for cutting off fuel supply to a gas engine, characterized in that, include: The rate of change of accelerator pedal opening is monitored. If the rate of change of accelerator pedal opening is greater than zero, it is determined that the driver has the intention to accelerate and it is predicted that the accelerator pedal will be deactivated soon. Calculate the risk level coefficient for fuel cut-off exit based on the current vehicle speed and the vehicle's overall speed ratio; Based on the aforementioned fuel cut-off exit risk level coefficient, fuel pre-injection control is performed before the fuel cut-off exit trigger signal is generated; The risk level coefficient for fuel cut-off exit, calculated based on the current vehicle speed and the vehicle's overall speed ratio, includes: Obtain the current vehicle speed and the overall vehicle speed ratio; Calculate the engine anti-drag speed based on the current vehicle speed and the vehicle's overall speed ratio; Based on the engine anti-drag speed, speed danger level parameters, and engine rated speed, calculate the theoretical risk level coefficient; The risk level coefficient for oil supply cut-off exit is determined based on the theoretical risk level coefficient. Based on the aforementioned fuel cut-off exit risk level coefficient, fuel pre-injection control is performed before the fuel cut-off exit trigger signal is generated, including: In response to the fuel cut-off exit risk level coefficient being in the low to medium risk range, fuel pre-injection is performed, and the amount of fuel pre-injection is less than the target injection amount; In response to the fuel cut-off exit risk level coefficient being in the high-risk range, a phased fuel injection strategy is executed, where the risk level in the high-risk range is higher than that in the medium-low risk range.

2. The gas engine fuel cut-off exit method according to claim 1, characterized in that, The risk level coefficient for the fuel cut-off exit is determined based on the theoretical risk level coefficient, including: The theoretical risk level coefficient is directly determined as the fuel shortage exit risk level coefficient; or, The theoretical risk level coefficient is corrected based on the exhaust manifold temperature to obtain the corrected risk level coefficient. The revised risk level coefficient is determined as the risk level coefficient for oil supply interruption exit.

3. The gas engine fuel cut-off exit method according to claim 2, characterized in that, The theoretical risk level coefficient is corrected based on the exhaust manifold temperature to obtain the corrected risk level coefficient, including: To obtain the exhaust manifold temperature and the ignition point of the fuel used in the gas engine; The theoretical risk level coefficient is corrected based on the ratio of the difference between the exhaust manifold temperature and the fuel ignition point to the fuel ignition point, resulting in the corrected risk level coefficient.

4. The gas engine fuel cut-off exit method according to claim 1, characterized in that, The execution of fuel pre-injection includes: Determine the target injection quantity based on the current engine speed and intake air volume; The percentage of injections with medium and low risk is calculated based on the fuel cut-off exit risk level coefficient, and the percentage of injections with medium and low risk decreases as the fuel cut-off exit risk level coefficient increases; The product of the low-to-medium risk injection percentage and the target injection amount is used as the fuel pre-injection amount, and fuel pre-injection is performed before the fuel cut-off exit trigger signal is generated.

5. The gas engine fuel cut-off exit method according to claim 1, characterized in that, The implementation of the phased fuel injection strategy includes: Calculate the percentage of high-risk injections based on the aforementioned fuel cut-off exit risk level coefficient; Before the fuel cut-off exit trigger signal is generated, the product of the high-risk injection percentage and the target injection amount is used as the injection amount for pre-injection, and pre-injection is performed to create a pre-injection atmosphere in the cylinder. In response to the generation of the fuel cut-off exit trigger signal, after the combustion state in the cylinder tends to stabilize, the fuel injection quantity is gradually increased to the target injection quantity; During the phased fuel injection strategy, the valve opening is adjusted in coordination to optimize the matching between the intake air volume and the phased fuel injection volume, thereby optimizing the combustion preparation state in the cylinder.

6. The gas engine fuel cut-off exit method according to claim 1, characterized in that, The fuel injection quantity in the fuel pre-injection control is determined based on the product of the injection percentage and the target injection quantity. The gas engine fuel cut-off exit method further includes: Obtain the current exhaust oxygen content and the target exhaust oxygen content range; In response to the current exhaust oxygen content being lower than a preset lower limit of the target exhaust oxygen content range, the oxygen content correction coefficient is increased to increase the injection percentage; In response to the current exhaust oxygen content being higher than a preset upper limit of the target exhaust oxygen content range, the oxygen content correction factor is reduced to decrease the injection percentage.

7. A fuel cut-off disconnection device for a gas engine, characterized in that, include: The monitoring unit is used to monitor the rate of change of the accelerator pedal opening. In response to the rate of change of the accelerator pedal opening being greater than zero, it determines that the driver has the intention to accelerate and predicts that the accelerator pedal will be deactivated soon. The calculation unit is used to calculate the risk level coefficient of fuel cut-off exit based on the current vehicle speed and the vehicle's overall speed ratio; An execution unit is used to perform fuel pre-injection control based on the fuel cut-off exit risk level coefficient before the fuel cut-off exit trigger signal is generated; Specifically, the computing unit is used for: Obtain the current vehicle speed and the overall vehicle speed ratio; Calculate the engine anti-drag speed based on the current vehicle speed and the vehicle's overall speed ratio; Based on the engine anti-drag speed, speed danger level parameters, and engine rated speed, calculate the theoretical risk level coefficient; The risk level coefficient for oil supply cut-off exit is determined based on the theoretical risk level coefficient. The execution unit is specifically used to perform fuel pre-injection in response to the fuel cut-off exit risk level coefficient being in the medium-low risk range, wherein the fuel pre-injection amount is less than the target injection amount; In response to the fuel cut-off exit risk level coefficient being in the high-risk range, a phased fuel injection strategy is executed, where the risk level in the high-risk range is higher than that in the medium-low risk range.

8. An engine controller, characterized in that, Including memory and processor; The memory is used to store at least one instruction; The processor is used to execute the at least one instruction to implement the gas engine fuel cut-off exit method as described in any one of claims 1 to 6.

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