Ignition angle self-adaptive control method and device

Abstract

The invention provides a self-adaptive control method and device for an ignition angle, and relates to the technical field of vehicles, the method comprises the steps that the current working condition of an engine is determined according to state parameters of the engine, and the current working condition comprises a fuel cut-off recovery working condition and an acceleration working condition; when the current working condition is the fuel cut-off recovery working condition, an ignition delay angle is determined based on the current rotating speed of the engine and the fuel cut-off recovery cycle number; and when the current working condition is the acceleration working condition, the ignition delay angle is determined on the basis of an air inflow difference value, the air inflow difference value represents the difference between the current air inflow of the engine in the current period and the expected air inflow of the engine in the next period, and the ignition delay angle is adjusted in a self-adaptive mode under the transient working condition, and knocking is avoided.

Description

Technical Field

[0001] This application relates to the field of vehicle technology, and more specifically, to an ignition angle adaptive control method and device. Background Technology

[0002] The engine in a vehicle performs functions such as driving and generating electricity. Ignition timing control is one of the core functions of the electronic control system, directly affecting vehicle safety and driving comfort. When the combustion state in the engine cylinder changes abruptly, the ignition timing cannot be set too early; otherwise, it can easily lead to premature auto-ignition of the air-fuel mixture, causing knocking.

[0003] In related technologies, engine ignition timing control relies on a knock sensor that monitors the combustion state within the cylinder in real time and feeds the signal back to the engine control unit (ECU). The ECU dynamically adjusts the ignition advance angle based on the knock signal to maximize thermal efficiency and output torque while avoiding knocking. However, in operating conditions such as frequent start-stop cycles and rapid load changes in hybrid vehicles, misjudgments or response delays can easily occur. Summary of the Invention

[0004] The problem addressed in this application is how to adaptively adjust the ignition delay angle under transient conditions to avoid knocking.

[0005] To address the aforementioned issues, this application provides an adaptive ignition angle control method and apparatus.

[0006] Firstly, this application provides an adaptive ignition angle control method, including: The current operating condition of the engine is determined based on the engine's status parameters, wherein the current operating condition includes fuel cut-off recovery condition and acceleration condition. When the current operating condition is the fuel cut-off recovery condition, the ignition delay angle is determined based on the engine's current speed and the number of fuel cut-off recovery cycles; When the current operating condition is the acceleration operating condition, the ignition delay angle is determined based on the intake air volume difference, wherein the intake air volume difference represents the difference between the current intake air volume of the engine in the current cycle and the expected intake air volume of the engine in the next cycle.

[0007] Optionally, determining the current operating condition of the engine based on its state parameters includes: When the state parameters meet all the fuel cut-off recovery determination conditions, the current operating condition is determined to be the fuel cut-off recovery operating condition. The fuel cut-off recovery determination conditions include the number of fuel cut-off recovery cycles being less than a first preset number, the current speed being greater than or equal to a first speed, the engine output torque being less than or equal to the required torque to suppress fuel cut-off, the engine speed acceleration in each cycle being greater than or equal to a preset speed acceleration, and the second speed being greater than the first speed.

[0008] Optionally, when the current operating condition is the fuel cut-off recovery condition, determining the ignition delay angle based on the engine's current speed and the number of fuel cut-off recovery cycles includes: The base value of fuel cut-off recovery ignition delay is determined based on the current speed and the number of fuel cut-off recovery cycles. When the fuel cut-off rate of the engine is greater than or equal to the fuel cut-off rate threshold, the engine is determined to be in a fuel cut-off state. When the fuel cut-off rate is less than the fuel cut-off rate threshold, the engine is determined to be in a fuel cut-off recovery state. The ignition delay angle is obtained by introducing the intake and exhaust valve overlap and the intake and exhaust overlap backflow based on the basic value of the fuel cut-off recovery ignition delay.

[0009] Optionally, the ignition angle adaptive control method further includes: The first ignition delay limit angle is determined based on the current engine speed and the actual intake air volume of the engine. The second ignition delay limiting angle is obtained based on the engine's ignition efficiency and the preset optimal ignition advance angle; The maximum value between the first ignition delay limit angle and the second ignition delay limit angle is taken as the ignition delay limit angle; The ignition delay angle is determined within the range of the ignition delay limit angle.

[0010] Optionally, determining the ignition delay angle within the range corresponding to the ignition delay limit angle includes: Under the fuel cut-off recovery condition, when the number of fuel cut-off recovery cycles is less than a first preset number, an offset value is determined based on the difference between the ignition delay angle and the number of fuel cut-off recovery cycles. The ignition delay angle is limited by the offset value and the ignition delay limit angle together. And / or, under the fuel cut-off recovery condition, when the number of fuel cut-off recovery cycles is greater than or equal to a first preset number, the ignition delay angle is set to 0.

[0011] Optionally, determining the current operating condition of the engine based on its state parameters further includes: When the engine is not in the starting state and the state parameters meet all acceleration determination conditions, the current operating condition is determined to be the acceleration operating condition. The acceleration determination conditions include the expected intake air volume difference being greater than a preset threshold and the current speed being less than or equal to a third speed.

[0012] Optionally, the ignition angle adaptive control method further includes: The current desired air intake volume is combined with the preset number of historical air intake volumes to form an air intake volume array; The number of delay cycles is determined based on the current rotational speed; Based on the number of delay cycles, the historical expected intake volume is determined from the intake volume array; The expected air intake difference is determined based on the current expected air intake and the historical expected air intake.

[0013] Optionally, when the current operating condition is the acceleration operating condition, determining the ignition delay angle based on the intake air volume difference includes: The ignition delay baseline value is determined based on the intake volume difference. The ignition delay angle is determined by compensating the baseline ignition delay value using a knock compensation coefficient.

[0014] Optionally, the ignition angle adaptive control method further includes: When the state parameters do not meet the acceleration determination conditions, determine whether the acceleration delay ignition angle of the previous cycle is greater than the acceleration delay ignition angle threshold. If the value is greater than the acceleration delay ignition angle threshold, then the ignition angle reduction value is determined based on the current rotational speed; If the value is less than or equal to the acceleration delay ignition angle threshold, then the ignition delay angle reference value is determined based on the current rotational speed, and a preset weight is assigned to the ignition delay angle reference value to obtain the ignition angle reduction value. The difference between the acceleration delay ignition angle of the previous cycle and the decrease in the ignition angle is compared with 0, and the maximum value is taken as the ignition delay angle of the current cycle.

[0015] Secondly, this application provides an ignition angle adaptive control device, comprising: The operating condition determination module is used to determine the current operating condition of the engine based on the engine's state parameters, wherein the current operating condition includes fuel cut-off recovery condition and acceleration condition. The fuel cut-off recovery ignition delay module is used to determine the ignition delay angle based on the engine's current speed and the number of fuel cut-off recovery cycles when the current operating condition is the fuel cut-off recovery condition. An acceleration ignition delay module is used to determine the ignition delay angle based on the intake air volume difference when the current operating condition is the acceleration operating condition, wherein the intake air volume difference represents the difference between the current intake air volume of the engine in the current cycle and the expected intake air volume of the engine in the next cycle.

[0016] The beneficial effects of the ignition angle adaptive control method in this application are: Based on engine state parameters, fuel cut-off recovery and acceleration conditions are determined, distinguishing between these two typical transient processes. The causes and combustion characteristics of knock differ under different conditions, and this categorization makes the ignition control strategy more targeted. Current engine speed indirectly reflects the combustion state within the cylinder, while the number of fuel cut-off cycles reflects the stage of the recovery process. Combining these two factors dynamically reflects the risk of knocking within the cylinder, allowing for adjustment of the ignition delay angle. This allows the ignition delay angle to adaptively change in the early and late stages of recovery, achieving adaptive suppression of the intensity of combustion during the fuel cut-off recovery process. The intake air volume difference reflects the change in intake demand caused by changes in throttle opening and is an indicator for determining transient knocking caused by rapid acceleration. Using the intake air volume difference as a delay basis allows for proactive ignition delay before knocking occurs, avoiding power loss or insufficient protection caused by a fixed ignition delay angle during rapid acceleration. By distinguishing different engine conditions using engine state parameters and determining strategies through different ignition delay angles, the ignition angle can be adaptively and dynamically adjusted according to the knocking risk under both fuel cut-off recovery and rapid acceleration transient conditions. Attached Figure Description

[0017] Figure 1 This is a flowchart illustrating the ignition angle adaptive control method according to an embodiment of this application; Figure 2 This is a flowchart illustrating the process of determining the ignition delay angle under fuel cut-off recovery conditions according to an embodiment of this application. Figure 3 This is a flowchart illustrating the process of determining the ignition delay angle under acceleration conditions according to an embodiment of this application. Figure 4 This is an example diagram of a vehicle according to an embodiment of this application. Detailed Implementation

[0018] To make the above-mentioned objects, features, and advantages of this application more apparent and understandable, specific embodiments of this application are described in detail below with reference to the accompanying drawings. Although some embodiments of this application are shown in the drawings, it should be understood that this application can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of this application. It should be understood that the accompanying drawings and embodiments of this application are for illustrative purposes only and are not intended to limit the scope of protection of this application.

[0019] It should be understood that the steps described in the method embodiments of this application may be performed in different orders and / or in parallel. Furthermore, the method embodiments may include additional steps and / or omit the steps shown. The scope of this application is not limited in this respect.

[0020] The term "comprising" and its variations as used herein are open-ended, meaning "including but not limited to"; the term "based on" means "at least partially based on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments"; and the term "optionally" means "optional embodiments". Definitions of other terms will be given in the description below. It should be noted that the concepts of "first," "second," etc., mentioned in this application are used only to distinguish different devices, modules, or units, and are not intended to limit the order of functions performed by these devices, modules, or units or their interdependencies.

[0021] It should be noted that the terms "one" and "more" used in this application are illustrative rather than restrictive, and those skilled in the art should understand that, unless otherwise expressly indicated in the context, they should be understood as "one or more".

[0022] The names of messages or information exchanged between multiple devices in the embodiments of this application are for illustrative purposes only and are not intended to limit the scope of these messages or information.

[0023] like Figure 1 As shown in the figure, an adaptive ignition angle control method provided in this application includes: Step S100: Determine the current operating condition of the engine based on the engine's status parameters, wherein the current operating condition includes fuel cut-off recovery condition and acceleration condition.

[0024] In this embodiment, the fuel cut-off recovery condition refers to the stage after the engine has cut off fuel supply, when the driver requests torque again, the throttle opens, and fuel is re-injected. During the fuel cut-off recovery condition, the air-fuel mixture concentration and temperature distribution in the combustion chamber may be uneven, with less residual exhaust gas in the cylinder, a higher proportion of fresh air, and a faster combustion rate. If ignition is too early under these conditions, some parts of the air-fuel mixture may spontaneously combust before the flame arrives, causing knocking. To mitigate this risk, a temporary ignition delay needs to be applied and gradually phased out as the number of combustion cycles increases.

[0025] Acceleration mode refers to the driver pressing the accelerator pedal to accelerate rapidly. Under this condition, the throttle opening increases rapidly, the intake air volume increases sharply, and the cylinder load increases rapidly. If the ignition advance angle is too large at this time, a large amount of fresh air enters the combustion chamber, and the compression pressure and temperature will rise sharply, which may cause the unburned mixture to ignite prematurely and produce knocking.

[0026] Both operating conditions are non-steady-state combustion processes, where actual combustion conditions deviate from the steady-state calibration boundary, and the probability of knocking increases significantly in a short period of time. By distinguishing between the types of operating conditions, corresponding ignition angle adjustment strategies can be activated in a targeted manner.

[0027] Step S110: When the current operating condition is the fuel cut-off recovery condition, determine the ignition delay angle based on the current engine speed and the number of fuel cut-off recovery cycles.

[0028] In this embodiment, the current rotational speed represents the engine's operating speed, which directly affects the duration of each combustion cycle and the gas flow within the cylinder.

[0029] The number of fuel cut-off recovery cycles indicates the effective injection cycles executed since fuel supply was restored, and is used to measure the time spent in the fuel cut-off recovery process. The smaller the number of fuel cut-off recovery cycles, the closer it is to the first combustion after fuel cut-off, the higher the proportion of fresh air in the cylinder, and the stronger the tendency for knocking; as the number of cycles increases, residual exhaust gas gradually accumulates, and combustion conditions gradually return to normal.

[0030] The ignition delay angle, determined based on two parameters—current engine speed and number of fuel cut-off recovery cycles—represents the ignition advance angle actively delayed relative to the optimal torque ignition angle (MBT). It is used to suppress excessively rapid combustion and sudden increases in local pressure caused by high concentrations of fresh air during the initial fuel cut-off recovery phase, reducing the risk of knocking and minimizing the impact of sudden torque increases.

[0031] By linking the ignition delay to the number of fuel cut-off recovery cycles, we avoid over-intervention or insufficient protection caused by using a fixed delay value. A larger delay angle is applied in the early stages of fuel cut-off recovery to ensure safety, while the delay is gradually reduced after fuel cut-off recovery to restore the ignition angle, achieving synergistic optimization of safety and driving smoothness.

[0032] Step S120: When the current operating condition is the acceleration operating condition, the ignition delay angle is determined based on the intake air volume difference, wherein the intake air volume difference represents the difference between the current intake air volume of the engine in the current cycle and the expected intake air volume of the engine in the next cycle.

[0033] Current air volume represents the actual amount of air entering the cylinder during the current combustion cycle. It can be obtained through sensor measurement or model estimation and reflects the current combustion load status.

[0034] The expected intake volume for the next cycle is the target intake volume for the next combustion cycle planned by the torque module based on the driver's request and the vehicle control objectives, which is used to reflect the upcoming load change trend.

[0035] The intake volume difference represents the difference between the expected intake volume in the next cycle and the current intake volume, reflecting the magnitude of the increase in intake demand. The larger the intake volume difference, the stronger the acceleration intention and the higher the risk of in-cylinder knocking.

[0036] The ignition delay angle, determined based on the intake air volume difference, is an ignition advance angle that is actively delayed relative to the optimal torque ignition angle (MBT) to suppress transient knocking. It is used to reduce combustion intensity before knocking occurs, lowering the rate of increase in peak cylinder pressure and temperature, thereby preventing abnormal combustion.

[0037] In this embodiment, the fuel cut-off recovery and acceleration conditions are determined based on the engine's state parameters, distinguishing between these two typical transient processes. The causes and combustion characteristics of knock differ under different conditions, and this classification makes the ignition control strategy more targeted. The current engine speed indirectly reflects the combustion state within the cylinder, while the number of fuel cut-off recovery cycles reflects the stage of the recovery process. Combining these two factors dynamically reflects the knock risk within the cylinder, allowing for adjustment of the ignition delay angle. This allows the ignition delay angle to adaptively change in the early and late stages of recovery, achieving adaptive suppression of the intense combustion during the fuel cut-off recovery process. The intake air volume difference reflects the change in intake demand caused by changes in throttle opening and is an indicator for determining transient knock caused by rapid acceleration. Using the intake air volume difference as a delay basis allows for proactive ignition delay before knock occurs, avoiding power loss or insufficient protection caused by a fixed ignition delay angle during rapid acceleration. By distinguishing different engine conditions based on engine state parameters and determining strategies through different ignition delay angles, the ignition angle can be adaptively and dynamically adjusted according to the knock risk under both fuel cut-off recovery and rapid acceleration transient conditions.

[0038] Optionally, such as Figure 2 As shown, determining the current operating condition of the engine based on its state parameters includes: When the state parameters meet all the fuel cut-off recovery determination conditions, the current operating condition is determined to be the fuel cut-off recovery operating condition. The fuel cut-off recovery determination conditions include the number of fuel cut-off recovery cycles being less than a first preset number, the current speed being greater than or equal to a first speed, the engine output torque being less than or equal to the required torque to suppress fuel cut-off, the engine speed acceleration in each cycle being greater than or equal to a preset speed acceleration, and the second speed being greater than the first speed.

[0039] In one embodiment, if the number of fuel cut-off recovery cycles is less than a first preset number, it indicates that the engine is still in the fuel cut-off recovery period, the in-cylinder gas composition is not yet stable, and there is a certain risk of knocking. The current engine speed needs to be greater than or equal to a first speed to exclude idling or low-speed conditions, as combustion stability is poor under idling or low-speed conditions, and the ignition delay strategy is not applicable. The fuel cut-off recovery determination condition also needs to simultaneously satisfy the condition that the torque is less than or equal to the driver's required torque and the fuel cut-off suppression flag is 0, indicating that the fuel cut-off has not been cancelled and the engine has indeed experienced the process of the driver actively cutting off the fuel supply. The ignition delay angle is only calculated in such cases where fuel supply is restored after a genuine fuel cut-off. It is also necessary to exclude special cases where hardware protection does not allow fuel cut-off.

[0040] The second speed threshold is higher than the first speed threshold and is used to delineate the boundary of medium and low speed rapid deceleration conditions; when the current speed is greater than or equal to the second speed, no speed acceleration is limited; when the current speed is between the first speed and the second speed, the speed acceleration in each cycle is greater than or equal to the preset speed acceleration, excluding dragging conditions such as throttle closure and sudden load drop.

[0041] For example, if the first speed is set to 500 rpm, the second speed is set to 1700 rpm, and the preset speed acceleration is set to -500 rpm / s, then when the engine speed acceleration in each cycle is greater than or equal to -500 rpm / s, and other conditions are met simultaneously, calculate the ignition delay angle under the fuel cut-off recovery condition.

[0042] When the status parameters do not meet all the fuel cut-off recovery conditions, the ignition delay angle is set to 0 under the fuel cut-off recovery condition.

[0043] Optionally, such as Figure 2 As shown, when the current operating condition is the fuel cut-off recovery condition, determining the ignition delay angle based on the engine's current speed and the number of fuel cut-off recovery cycles includes: The base value of fuel cut-off recovery ignition delay is determined based on the current speed and the number of fuel cut-off recovery cycles. When the fuel cut-off rate of the engine is greater than or equal to the fuel cut-off rate threshold, the engine is determined to be in a fuel cut-off state. When the fuel cut-off rate is less than the fuel cut-off rate threshold, the engine is determined to be in a fuel cut-off recovery state. The ignition delay angle is obtained by introducing the intake and exhaust valve overlap and the intake and exhaust overlap backflow based on the basic value of the fuel cut-off recovery ignition delay.

[0044] In one embodiment, the fuel cut-off rate represents the proportion of cylinders in the engine that cut off fuel supply, used to determine whether the engine is in a fuel cut-off state; the fuel cut-off rate threshold represents a preset judgment boundary used to distinguish between fuel cut-off and non-fuel cut-off situations. When the fuel cut-off rate drops below the fuel cut-off rate threshold, it indicates that the engine has re-entered the fuel cut-off recovery state.

[0045] Optionally, the fuel cut-off rate threshold is set to 0.85, meaning that the engine is considered to be in a fuel cut-off state when 85% or more of the cylinders are cut off from fuel.

[0046] The number of fuel cut-off recovery cycles represents the number of cycles elapsed since the fuel cut-off rate fell below the threshold, reflecting the stage of fuel cut-off recovery. Combined with the current engine speed, the basic fuel cut-off recovery ignition delay value can be obtained by looking up a table or mapping. It decreases as the number of recovery cycles increases, reflecting the characteristic that the risk of knocking decreases as combustion stabilizes.

[0047] In one embodiment, the number of fuel cut-off recovery cycles is determined by a counter. When the fuel cut-off rate increases from below 0.85 to 0.85 or above, a fuel cut-off is determined, and the counter is reset to 0. When the fuel cut-off rate falls below 0.85 again, a fuel cut-off recovery state is determined, and the counter starts counting. After a limit is set, the number of cycles after the fuel cut-off recovery is calculated.

[0048] The intake and exhaust valve overlap represents the crankshaft angle range during which the intake and exhaust valves are simultaneously open, affecting the mixing ratio of residual exhaust gas and fresh air in the cylinder. The intake and exhaust valve overlap backflow represents the degree to which fresh intake air is expelled or external gases are drawn back into the cylinder due to valve overlap; both together reflect the influence of scavenging intensity on combustion intensity. The intake and exhaust valve overlap and intake and exhaust valve overlap backflow are used together as correction terms to adjust the base delay value, compensating for changes in knock tendency caused by valve timing differences.

[0049] In one embodiment, the ignition delay angle in the fuel cut-off recovery state is calculated as follows: A base value of the fuel cut-off recovery ignition delay, an_FuCutRBas, is obtained by looking up a table based on the engine speed and the number of fuel injection requests after fuel cut-off recovery (fuel cut-off recovery cycle number). An additional fuel cut-off recovery ignition delay, an_FuCutROverlap, influenced by intake and exhaust valve overlap, is introduced above this base value. After introducing the intake and exhaust valve overlap effect, a coefficient is further introduced, for example, multiplying this value by the intake and exhaust overlap backflow coefficient fac_BackFlowCmpn obtained from a table using the intake and exhaust overlap backflow volume to obtain the final base value of the ignition delay. Furthermore, a pedal compensation coefficient, an idle speed compensation coefficient, and an engine coolant temperature compensation coefficient are determined to obtain the final ignition delay angle. The pedal compensation coefficient is obtained by looking up the pedal position from a table, the idle speed compensation coefficient is determined by looking up a table or a preset coefficient, and the engine coolant temperature compensation coefficient is obtained by looking up the engine coolant temperature from a table.

[0050] In one embodiment, an example of a calibration table for the baseline value of the fuel cut-off recovery ignition delay is as follows:

[0051] An example of the fuel cut-off recovery ignition delay table affected by intake and exhaust valve overlap is as follows:

[0052] An example of the fuel cut-off recovery ignition delay table affected by intake and exhaust valve overlap is as follows:

[0053] Optionally, the ignition angle adaptive control method further includes: The first ignition delay limit angle is determined based on the current engine speed and the actual intake air volume of the engine. The second ignition delay limiting angle is obtained based on the engine's ignition efficiency and the preset optimal ignition advance angle; The maximum value between the first ignition delay limit angle and the second ignition delay limit angle is taken as the ignition delay limit angle; The ignition delay angle is determined within the range of the ignition delay limit angle.

[0054] The ignition delay limit angle, i.e., the maximum ignition delay threshold, is determined using two different methods. The first ignition delay limit angle is determined from the physical boundary path based on the engine's current speed and actual intake air volume. The second ignition delay limit angle is determined from the torque safety path based on the engine's ignition efficiency and optimal ignition advance angle. The two values ​​are compared, and the larger one is taken as the ignition delay limit angle, used to constrain the maximum ignition delay angle under fuel cut-off recovery and acceleration conditions.

[0055] In one embodiment, the first ignition delay limit angle is calculated as follows: the basic ignition angle an_Base is obtained by looking up a table using the current engine speed and the actual intake air volume. Temperature compensation ignition angle and pressure compensation ignition angle are added to the basic ignition angle an_Base. The temperature compensation ignition angle is obtained by looking up a table using the intake air temperature and the coolant temperature, and the pressure compensation ignition angle is obtained by looking up a table using the ambient pressure and the actual intake air volume.

[0056] The second ignition delay limit angle is calculated as follows: use the current engine speed and actual intake air volume to look up the ignition efficiency in a table, then look up the ignition angle in the table using the ignition efficiency, and then subtract this value from the optimal ignition advance angle (MBT) to obtain the second ignition delay limit angle calculated by the torque module.

[0057] Optionally, determining the ignition delay angle within the range corresponding to the ignition delay limit angle includes: Under the fuel cut-off recovery condition, when the number of fuel cut-off recovery cycles is less than a first preset number, an offset value is determined based on the difference between the ignition delay angle and the number of fuel cut-off recovery cycles. The ignition delay angle is limited by the offset value and the ignition delay limit angle together. And / or, under the fuel cut-off recovery condition, when the number of fuel cut-off recovery cycles is greater than or equal to a first preset number, the ignition delay angle is set to 0.

[0058] When the number of fuel cut-off recovery cycles is less than the first preset number, the proportion of fresh air in the engine cylinder is high, and the combustion is intense. Ignition delay needs to be applied to suppress knocking. An offset value is introduced to further constrain the ignition delay angle. The offset value is obtained by looking up a table or a preset function mapping based on the number of fuel cut-off recovery cycles. It decreases as the number of cycles increases, reflecting the characteristic of gradually reducing risk during the recovery process.

[0059] The offset value is subtracted from the ignition delay limit angle to form a stricter upper limit for the delay angle. The delay boundary is actively tightened in the early stage of recovery to improve combustion stability while ensuring knock suppression. The limit is gradually relaxed as the recovery process progresses to achieve a dynamic balance between safety and performance.

[0060] When the number of fuel cut-off recovery cycles is greater than or equal to the first preset number, the ignition delay angle is directly constrained by the ignition delay limit angle.

[0061] Optionally, the first preset number of times is set to 16.

[0062] Optionally, determining the current operating condition of the engine based on its state parameters further includes: When the engine is not in the starting state and the state parameters meet all acceleration determination conditions, the current operating condition is determined to be the acceleration operating condition. The acceleration determination conditions include the expected intake volume difference being greater than a preset threshold, the current speed being less than or equal to a third speed, and the engine starting duration being greater than a second preset duration.

[0063] The expected intake volume difference represents the change in the filtered expected intake volume between the current moment and the historical value, used to indicate the rate of increase in intake demand. When the expected intake volume difference is greater than a preset threshold, it indicates a rapid increase in intake volume, posing a risk of transient knocking due to a sudden rise in temperature and pressure. In one embodiment, the preset threshold is set to 0.08.

[0064] The third speed is used to limit the speed range for determining acceleration conditions; when the speed exceeds the third speed, the combustion cycle is shortened, the knock window is narrowed, and the control response margin is insufficient, so the feedforward delay logic based on intake dynamics is not applicable.

[0065] For example, if the third speed is set to 4000 rpm, feedforward delay logic based on intake dynamics is not applicable above this speed.

[0066] The second preset duration and engine coolant temperature are used to exclude the initial stage of cold start, that is, to exclude the stage when the engine is in the starting state. At this time, the coolant temperature is low, the air-fuel mixture is poorly atomized, the combustion is unstable, and the causes of knocking are complex. Therefore, it is not advisable to adopt a control strategy that accelerates knocking under hot engine conditions.

[0067] Optionally, such as Figure 3 As shown, before determining whether the state parameters satisfy all acceleration determination conditions, the process also includes: Determine if the engine is in start-up mode; When the engine start-up time exceeds the second preset time, it is determined that the engine is not in start-up mode; When the engine start-up time is less than or equal to the second preset time, the engine is determined to be in start-up mode; Proceed to the step of determining whether the state parameters satisfy all acceleration determination conditions; When the state parameters meet all acceleration determination conditions, the current operating condition is determined to be the acceleration operating condition. The acceleration determination conditions include the expected intake volume difference being greater than a preset threshold and the current speed being less than or equal to a third speed.

[0068] When the state parameters do not meet the acceleration determination conditions, determine whether the acceleration delay ignition angle of the previous cycle is greater than the acceleration delay ignition angle threshold. If the value is greater than the acceleration delay ignition angle threshold, then the ignition angle reduction value is determined based on the current rotational speed; If the value is less than or equal to the acceleration delay ignition angle threshold, then the ignition delay angle reference value is determined based on the current rotational speed, and a preset weight is assigned to the ignition delay angle reference value to obtain the ignition angle reduction value. The difference between the acceleration delay ignition angle of the previous cycle and the decrease in the ignition angle is compared with 0, and the maximum value is taken as the ignition delay angle of the current cycle.

[0069] For example, the second preset duration is set to 25 seconds.

[0070] Optionally, the acceleration determination conditions also include an engine coolant temperature greater than or equal to a threshold of 25 degrees Celsius, and an actual engine intake volume greater than or equal to the minimum intake volume and less than or equal to the maximum intake volume.

[0071] Optionally, the ignition angle adaptive control method further includes: The current desired air intake volume is combined with the preset number of historical air intake volumes to form an air intake volume array; The number of delay cycles is determined based on the current rotational speed; Based on the number of delay cycles, the historical expected intake volume is determined from the intake volume array; The expected air intake difference is determined based on the current expected air intake and the historical expected air intake.

[0072] In one embodiment, the current desired intake volume at the current moment is first-order filtered and then combined with a preset number of historical intake volumes to form a first-in-first-out (FIFO) array. The current desired intake volume replaces the historical intake volume in the array with the longest time difference from the current moment, thus forming an intake volume array. The delay cycle number is determined by looking up a table based on the engine's current speed. The delay cycle number represents the number of control cycles closest to the preset time interval at the current speed. Based on the delay cycle number, the corresponding historical desired intake volume is selected from the intake volume array as a reference value before the preset time interval, thereby determining the historical desired intake volume before the preset time interval. The difference between the current desired intake volume and the historical desired intake volume is calculated to obtain the desired intake volume difference value.

[0073] Optionally, the intake volume array is a 33-bit array, including 32 bits of historical expected intake volume and 1 bit of current expected intake volume. The preset time interval is set to 20 milliseconds.

[0074] In one embodiment, an example of a calibration table for engine speed and the number of delay cycles is as follows:

[0075] Optionally, when the current operating condition is the acceleration operating condition, determining the ignition delay angle based on the intake air volume difference includes: The ignition delay baseline value is determined based on the intake volume difference. The ignition delay angle is determined by compensating the baseline ignition delay value using a knock compensation coefficient.

[0076] In one embodiment, the ignition delay an_BasRtd is obtained by looking up a table using the engine's independent speed and the difference between the actual intake volume in the current cycle and the expected intake volume in the next cycle. Then, the ignition delay is multiplied by a knock compensation coefficient and a temperature compensation coefficient fac_TeCmpn to obtain the compensated ignition delay angle. The knock compensation coefficient is obtained by looking up the average adaptive ignition angle of the cylinder under maximum intake volume conditions, and the temperature compensation coefficient is obtained by looking up the engine intake air temperature and coolant temperature.

[0077] Optionally, the ignition angle adaptive control method further includes: When the state parameters do not meet the acceleration determination conditions, determine whether the acceleration delay ignition angle of the previous cycle is greater than the acceleration delay ignition angle threshold. If the value is greater than the acceleration delay ignition angle threshold, then the ignition angle reduction value is determined based on the current rotational speed; If the value is less than or equal to the acceleration delay ignition angle threshold, then the ignition delay angle reference value is determined based on the current rotational speed, and a preset weight is assigned to the ignition delay angle reference value to obtain the ignition angle reduction value. The difference between the acceleration delay ignition angle of the previous cycle and the decrease in the ignition angle is compared with 0, and the maximum value is taken as the ignition delay angle of the current cycle.

[0078] In one embodiment, when the acceleration determination condition is not met, the required reduction in ignition angle under that operating condition is determined based on the acceleration delay ignition angle threshold. For example, when the acceleration delay ignition angle of the previous cycle is greater than the acceleration delay ignition angle threshold, the required reduction in ignition angle is directly obtained by looking up the engine speed in a table; when the acceleration delay ignition angle of the previous cycle is less than or equal to the acceleration delay ignition angle threshold, the required reduction in ignition angle obtained by looking up the engine speed in a table is used as a reference value for the ignition delay angle, and a preset weight is further assigned to obtain the ignition angle reduction value. The reduction is then compared with 0 by subtracting this reduction from the acceleration delay ignition angle of the previous cycle, and the maximum value is taken to obtain the final reduced ignition delay angle. As time increases, the reduced ignition delay angle eventually equals 0.

[0079] Optionally, the acceleration delay ignition angle threshold is set to 40°. That is, if the ignition angle is greater than 40°, the amount of ignition angle to be reduced is obtained by looking up a table based on the current engine speed; if the ignition angle is less than or equal to 40°, the preset base reduction value is multiplied by a coefficient of 0.1 as the amount of ignition angle to be reduced this time. The reduction amount is subtracted from the acceleration delay ignition angle of the previous cycle, and the maximum value is taken from 0 to obtain the ignition delay angle of the current cycle; this is recursively applied with the control cycle, achieving an exponential decay trend.

[0080] An example of a calibration table between engine speed and the required reduction in ignition angle is as follows:

[0081] This application provides an embodiment of an adaptive ignition angle control device, comprising: The operating condition determination module is used to determine the current operating condition of the engine based on the engine's state parameters, wherein the current operating condition includes fuel cut-off recovery condition and acceleration condition. The fuel cut-off recovery ignition delay module is used to determine the ignition delay angle based on the engine's current speed and the number of fuel cut-off recovery cycles when the current operating condition is the fuel cut-off recovery condition. An acceleration ignition delay module is used to determine the ignition delay angle based on the intake air volume difference when the current operating condition is the acceleration operating condition, wherein the intake air volume difference represents the difference between the current intake air volume of the engine in the current cycle and the expected intake air volume of the engine in the next cycle.

[0082] like Figure 4As shown in the embodiment of this application, a vehicle 400 includes a memory 410 and a processor 420; the memory 410 is used to store a computer program; the processor 420 is used to implement the ignition angle adaptive control method as described above when the computer program is executed.

[0083] Alternatively, a vehicle 400 includes a memory 410 and a processor 420 coupled to the memory 410; the memory 410 is configured to store a computer program; the processor 420 is configured to perform the following operations when the computer program is executed: The current operating condition of the engine is determined based on the engine's status parameters, wherein the current operating condition includes fuel cut-off recovery condition and acceleration condition. When the current operating condition is the fuel cut-off recovery condition, the ignition delay angle is determined based on the engine's current speed and the number of fuel cut-off recovery cycles; When the current operating condition is the acceleration operating condition, the ignition delay angle is determined based on the intake air volume difference, wherein the intake air volume difference represents the difference between the current intake air volume of the engine in the current cycle and the expected intake air volume of the engine in the next cycle.

[0084] This application provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, it implements the ignition angle adaptive control method as described above.

[0085] Alternatively, a non-volatile computer-readable storage medium storing a computer program that, when executed by a processor, causes the processor to perform the following operations: The current operating condition of the engine is determined based on the engine's status parameters, wherein the current operating condition includes fuel cut-off recovery condition and acceleration condition. When the current operating condition is the fuel cut-off recovery condition, the ignition delay angle is determined based on the engine's current speed and the number of fuel cut-off recovery cycles; When the current operating condition is the acceleration operating condition, the ignition delay angle is determined based on the intake air volume difference, wherein the intake air volume difference represents the difference between the current intake air volume of the engine in the current cycle and the expected intake air volume of the engine in the next cycle.

[0086] The following describes a vehicle 400 that can serve as a server or client of this application, including examples of hardware devices encompassing various aspects of this application. Vehicle 400 includes various forms of digital electronic computer equipment, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. Vehicle 400 may also include various forms of mobile devices, such as personal digital assistants, cellular phones, smartphones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely illustrative and are not intended to limit the implementation of the application described and / or claimed herein.

[0087] Vehicle 400 includes a computing unit that can perform various appropriate actions and processes based on a computer program stored in read-only memory (ROM) or a computer program loaded from a storage unit into random access memory (RAM). The RAM can also store various programs and data required for device operation. The computing unit, ROM, and RAM are interconnected via a bus. Input / output (I / O) interfaces are also connected to the bus.

[0088] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. The storage medium can be a magnetic disk, optical disk, read-only memory (ROM), or random access memory (RAM), etc. In this application, the units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of the embodiments of this application according to actual needs. Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated units can be implemented in hardware or as software functional units.

[0089] Although the above disclosure is provided, the scope of protection of this application is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of this application, and all such changes and modifications will fall within the scope of protection of this application.

Claims

1. An adaptive ignition angle control method, characterized in that, include: The current operating condition of the engine is determined based on the engine's status parameters, wherein the current operating condition includes fuel cut-off recovery condition and acceleration condition. When the current operating condition is the fuel cut-off recovery condition, the ignition delay angle is determined based on the engine's current speed and the number of fuel cut-off recovery cycles; When the current operating condition is the acceleration operating condition, the ignition delay angle is determined based on the intake air volume difference, wherein the intake air volume difference represents the difference between the current intake air volume of the engine in the current cycle and the expected intake air volume of the engine in the next cycle.

2. The ignition angle adaptive control method according to claim 1, characterized in that, Determining the current operating condition of the engine based on its state parameters includes: When the state parameters meet all the fuel cut-off recovery determination conditions, the current operating condition is determined to be the fuel cut-off recovery operating condition. The fuel cut-off recovery determination conditions include the number of fuel cut-off recovery cycles being less than a first preset number, the current speed being greater than or equal to a first speed, the engine output torque being less than or equal to the required torque to suppress fuel cut-off, the engine speed acceleration in each cycle being greater than or equal to a preset speed acceleration, and the second speed being greater than the first speed.

3. The ignition angle adaptive control method according to claim 1, characterized in that, When the current operating condition is the fuel cut-off recovery condition, determining the ignition delay angle based on the engine's current speed and the number of fuel cut-off recovery cycles includes: The base value of fuel cut-off recovery ignition delay is determined based on the current speed and the number of fuel cut-off recovery cycles. When the fuel cut-off rate of the engine is greater than or equal to the fuel cut-off rate threshold, the engine is determined to be in a fuel cut-off state. When the fuel cut-off rate is less than the fuel cut-off rate threshold, the engine is determined to be in a fuel cut-off recovery state. The ignition delay angle is obtained by introducing the intake and exhaust valve overlap and the intake and exhaust overlap backflow based on the basic value of the fuel cut-off recovery ignition delay.

4. The ignition angle adaptive control method according to claim 1, characterized in that, The ignition angle adaptive control method further includes: The first ignition delay limit angle is determined based on the current engine speed and the actual intake air volume of the engine. The second ignition delay limiting angle is obtained based on the engine's ignition efficiency and the preset optimal ignition advance angle; The maximum value between the first ignition delay limit angle and the second ignition delay limit angle is taken as the ignition delay limit angle; The ignition delay angle is determined within the range of the ignition delay limit angle.

5. The ignition angle adaptive control method according to claim 4, characterized in that, Determining the ignition delay angle within the range corresponding to the ignition delay limit angle includes: Under the fuel cut-off recovery condition, when the number of fuel cut-off recovery cycles is less than a first preset number, an offset value is determined based on the difference between the ignition delay angle and the number of fuel cut-off recovery cycles. The ignition delay angle is limited by the offset value and the ignition delay limit angle together. And / or, under the fuel cut-off recovery condition, when the number of fuel cut-off recovery cycles is greater than or equal to a first preset number, the ignition delay angle is set to 0.

6. The ignition angle adaptive control method according to any one of claims 1-5, characterized in that, The step of determining the current operating condition of the engine based on the engine's state parameters also includes: When the engine is not in the starting state and the state parameters meet all acceleration determination conditions, the current operating condition is determined to be the acceleration operating condition. The acceleration determination conditions include the expected intake air volume difference being greater than a preset threshold and the current speed being less than or equal to a third speed.

7. The ignition angle adaptive control method according to claim 6, characterized in that, The ignition angle adaptive control method further includes: The current desired air intake volume is combined with the preset number of historical air intake volumes to form an air intake volume array; The number of delay cycles is determined based on the current rotational speed; Based on the number of delay cycles, the historical expected intake volume is determined from the intake volume array; The expected air intake difference is determined based on the current expected air intake and the historical expected air intake.

8. The ignition angle adaptive control method according to any one of claims 1-5, characterized in that, When the current operating condition is the acceleration operating condition, determining the ignition delay angle based on the intake air volume difference includes: The ignition delay baseline value is determined based on the intake volume difference. The ignition delay angle is determined by compensating the baseline ignition delay value using a knock compensation coefficient.

9. The ignition angle adaptive control method according to any one of claims 1-5, characterized in that, The ignition angle adaptive control method further includes: When the state parameters do not meet the acceleration determination conditions, determine whether the acceleration delay ignition angle of the previous cycle is greater than the acceleration delay ignition angle threshold. If the value is greater than the acceleration delay ignition angle threshold, then the ignition angle reduction value is determined based on the current rotational speed; If the value is less than or equal to the acceleration delay ignition angle threshold, then the ignition delay angle reference value is determined based on the current rotational speed, and a preset weight is assigned to the ignition delay angle reference value to obtain the ignition angle reduction value. The difference between the acceleration delay ignition angle of the previous cycle and the decrease in the ignition angle is compared with 0, and the maximum value is taken as the ignition delay angle of the current cycle.

10. An adaptive ignition angle control device, characterized in that, include: The operating condition determination module is used to determine the current operating condition of the engine based on the engine's state parameters, wherein the current operating condition includes fuel cut-off recovery condition and acceleration condition. The fuel cut-off recovery ignition delay module is used to determine the ignition delay angle based on the engine's current speed and the number of fuel cut-off recovery cycles when the current operating condition is the fuel cut-off recovery condition. An acceleration ignition delay module is used to determine the ignition delay angle based on the intake air volume difference when the current operating condition is the acceleration operating condition, wherein the intake air volume difference represents the difference between the current intake air volume of the engine in the current cycle and the expected intake air volume of the engine in the next cycle.

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