Engine combustion noise control method

Abstract

The invention provides an engine combustion noise control method. The engine combustion noise control method comprises the steps that S1, operation state parameters of an engine are obtained; s2, the operation working condition of the engine is judged according to the operation state parameters, when the operation working condition is a steady-state working condition, combustion consistency in all piston cylinders of the engine is judged, and combustion correction is conducted on the piston cylinders which are uneven in combustion according to the judgment result; and when the operation working condition is the transient working condition, the current combustion noise change value of the engine is determined according to the mapping relation between the crankshaft rotating speed change rate and the combustion noise change value, and the combustion noise exceeding the set noise range is corrected. The problem that in the prior art, the control effect of an engine combustion noise control mode is poor is effectively solved.

Description

Technical Field

[0001] This invention relates to the field of engine technology, and more specifically, to a method for controlling engine combustion noise. Background Technology

[0002] Currently, in the field of engine technology, the control of engine combustion noise mainly relies on pre-set parameters and empirical adjustment strategies. Specifically, traditional combustion noise control methods typically involve determining a set of fixed operating parameters, such as injection timing, injection quantity, and rail pressure, through testing and calibration during the engine design phase, in order to achieve a relatively low level of combustion noise under steady-state operating conditions.

[0003] However, the aforementioned combustion noise control methods for engines have significant limitations when dealing with transient engine conditions. For example, when an engine suddenly accelerates from idle to high speed, the combustion state changes rapidly, such as an increase in combustion rate and combustion phase lag, which may lead to an increase in instantaneous combustion noise. Due to the lack of effective real-time diagnostic tools, traditional methods struggle to accurately capture and respond promptly to these subtle changes in combustion state, thus failing to achieve effective control of combustion noise. Summary of the Invention

[0004] The main objective of this invention is to provide an engine combustion noise control method to solve the problem of poor control effect of existing engine combustion noise control methods.

[0005] To achieve the above objectives, the present invention provides an engine combustion noise control method, comprising: step S1: acquiring engine operating state parameters; step S2: determining the engine operating condition based on the operating state parameters; when the operating condition is a steady-state condition, determining the combustion consistency in all piston cylinders of the engine, and correcting combustion in unevenly burning piston cylinders based on the determination result; when the operating condition is a transient condition, determining the current combustion noise change value of the engine based on the mapping relationship between the crankshaft speed change rate and the combustion noise change value, and correcting combustion noise exceeding the set noise range.

[0006] Furthermore, the method for determining the engine's operating condition based on operating state parameters includes: if the rate of change of engine speed, the rate of change of torque, and the rate of change of throttle stroke are all greater than zero, then the operating condition is determined to be a transient condition; otherwise, the operating condition is determined to be a steady-state condition.

[0007] Furthermore, the method for determining the combustion consistency in all piston cylinders of the engine includes: setting the crankshaft speed fluctuation rate of one piston cylinder as a preset speed fluctuation rate; if the ratio of the crankshaft speed fluctuation rate of any other piston cylinder to the preset speed fluctuation rate is within the preset ratio range, then the combustion in that piston cylinder is determined to be uniform; if the ratio of the crankshaft speed fluctuation rate of any other piston cylinder to the preset speed fluctuation rate exceeds the preset ratio range, then combustion correction is required for that piston cylinder; wherein, the preset ratio range is 1 to 1.05.

[0008] Furthermore, the method for establishing the mapping relationship between the crankshaft speed change rate and the combustion noise change value includes: Step S21: Adjusting the engine operating parameters to change the engine combustion state and collecting the combustion noise change value of the engine; Step S22: Collecting the square wave signal of the crankshaft speed and processing the square wave signal for transient speed change and transient speed change rate to obtain a correspondence table between the crankshaft speed change value and the combustion noise change value under different operating parameters. The correspondence table is the mapping relationship between the crankshaft speed change rate and the combustion noise change value.

[0009] Furthermore, the method for processing transient speed changes and transient speed change rates of square wave signals includes: Step S23: According to formula n i =△α / (△t multiplied by 360) gives the transient speed change n i Where i = 1, 2, 3…, n, Δα is the angle difference between two pulses of the square wave signal, and Δt is the time difference between two pulses of the square wave signal; Step S24: According to the formula Δn = [max(n1, n2, n3…, n…] j )-min(n1,n2,n3…,n j )] / △α n The transient speed change rate Δn is obtained; where j=1,2,3…,i, Δα n denoted as the angle difference between the maximum and minimum rotational speeds within the window period of the square wave signal; where the transient rotational speed change rate Δn is the crankshaft speed change value.

[0010] Furthermore, the method for correcting combustion noise that exceeds the set noise range includes: adjusting at least one of the following based on the threshold range of the noise change value ΔS of the combustion noise: throttle filter, common rail pressure, main injection angle, and pre-injection interval angle.

[0011] Furthermore, based on the threshold range of the noise change value ΔS of combustion noise, the method for adjusting at least one of the following: circulating fuel supply, common rail pressure, main injection angle, and pre-injection interval angle includes: if 0.5dBA≤ΔS<1.0dBA, then delay the main injection angle and increase the pre-injection interval angle; if 1.0dBA≤ΔS<2.0dBA, then reduce the common rail pressure, delay the main injection angle, and increase the pre-injection interval angle; if ΔS≥2.0dBA, then reduce the circulating fuel supply, reduce the common rail pressure, delay the main injection angle, and increase the pre-injection interval angle.

[0012] Furthermore, when the operating condition is transient, each piston cylinder undergoes a cycle as a judgment period. In one judgment period, if the proportion of the combustion noise change value ΔS exceeding 0.5 dBA is greater than or equal to 50%, then at least one of the following is adjusted according to the threshold range of the noise change value ΔS with the highest proportion: throttle filter, common rail pressure, main injection angle, and pre-injection interval angle.

[0013] Furthermore, the engine combustion noise control method also includes: during the process of correcting combustion noise, if the combustion noise still exceeds the set noise range after the correction time reaches a preset time value, the engine is controlled to issue a fault alarm signal.

[0014] Furthermore, the method for selecting the window period of the square wave signal includes: acquiring the engine's knock pressure signal, and taking the region in the square wave signal with the largest speed fluctuation and the largest combustion noise as the window period.

[0015] By applying the technical solution of this invention, engine operating parameters are monitored and analyzed in real time to accurately identify engine operating conditions and adjust combustion parameters accordingly. This significantly improves the accuracy and response speed of engine combustion noise control, thereby effectively reducing engine combustion noise and improving product NVH performance while ensuring the power and economy of the diesel engine. This solves the problem of poor control effect in existing engine combustion noise control methods. Specifically, during engine operation, engine operating parameters, including but not limited to crankshaft speed, throttle opening, and torque, are first acquired to provide basic data for subsequent combustion state identification and correction. Then, based on the acquired operating parameters, the current engine operating condition is determined, i.e., steady-state or transient. Under steady-state conditions, the combustion consistency of each piston cylinder is monitored. If uneven combustion is detected, combustion correction is immediately performed on the problematic piston cylinder to restore combustion consistency. Under transient conditions, the engine combustion noise level is evaluated based on the mapping relationship between crankshaft speed change rate and combustion noise. If the combustion noise exceeds the set noise range, adjustments are made according to a preset correction strategy to reduce combustion noise. Meanwhile, considering the special characteristics of transient operating conditions, the reliability and effectiveness of the correction strategy are ensured by setting a reasonable combustion state correction threshold. Attached Figure Description

[0016] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0017] Figure 1 A flowchart illustrating the determination of engine operating conditions according to an embodiment of the engine combustion noise control method of the present invention is shown.

[0018] Figure 2 It shows Figure 1 The control flowchart of the engine combustion noise control method. Detailed Implementation

[0019] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0020] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0021] In this invention, unless otherwise stated, directional terms such as "up" and "down" are generally used in relation to the direction shown in the accompanying drawings, or in relation to the vertical, perpendicular, or gravitational direction; similarly, for ease of understanding and description, "left" and "right" are generally used in relation to the left and right shown in the accompanying drawings; "inner" and "outer" refer to the inner and outer contours of each component itself, but the above directional terms are not intended to limit this invention.

[0022] To address the problem of poor control performance of existing engine combustion noise control methods, this application provides an engine combustion noise control method.

[0023] like Figure 1 and Figure 2 As shown, the engine combustion noise control method includes:

[0024] Step S1: Obtain the engine's operating status parameters;

[0025] Step S2: Determine the engine's operating condition based on the operating status parameters. When the operating condition is steady-state, determine the combustion consistency in all piston cylinders of the engine and correct the combustion of piston cylinders with uneven combustion based on the determination result. When the operating condition is transient, determine the current combustion noise change value of the engine based on the mapping relationship between the crankshaft speed change rate and the combustion noise change value, and correct the combustion noise that exceeds the set noise range.

[0026] By applying the technical solution of this embodiment, engine operating status parameters are monitored and analyzed in real time to accurately identify engine operating conditions and adjust combustion parameters accordingly. This significantly improves the control accuracy and response speed of engine combustion noise, thereby effectively reducing engine combustion noise and improving product NVH performance while ensuring the power and economy of the diesel engine. This solves the problem of poor control effect in existing engine combustion noise control methods. Specifically, during engine operation, engine operating status parameters, including but not limited to crankshaft speed, throttle opening, and torque, are first acquired to provide basic data for subsequent combustion state identification and correction. Then, based on the acquired operating status parameters, the current engine operating condition is determined, i.e., steady-state or transient. Under steady-state conditions, the combustion consistency of each piston cylinder is monitored. If uneven combustion is detected, combustion correction is immediately performed on the problematic piston cylinder to restore combustion consistency. Under transient conditions, the engine combustion noise level is evaluated based on the mapping relationship between crankshaft speed change rate and combustion noise. If the combustion noise exceeds the set noise range, adjustments are made according to a preset correction strategy to reduce combustion noise. Meanwhile, considering the special characteristics of transient operating conditions, the reliability and effectiveness of the correction strategy are ensured by setting a reasonable combustion state correction threshold.

[0027] In this embodiment, the above method ensures that the engine can accurately identify the engine combustion conditions and noise levels in complex driving environments, and quickly take effective measures to optimize combustion parameters, thereby reducing engine combustion noise.

[0028] In this embodiment, the method for determining the engine's operating condition based on operating status parameters includes:

[0029] If the rate of change of engine speed, the rate of change of torque, and the rate of change of throttle travel are all greater than zero, the operating condition is determined to be a transient condition; otherwise, the operating condition is determined to be a steady-state condition.

[0030] Specifically, by monitoring and analyzing the rate of change of engine operating parameters in real time, the engine's operating state is precisely quantified, and steady-state and transient conditions are identified. This achieves the goal of timely and accurate determination of the engine's operating condition, thereby realizing the technical effect of optimizing the combustion noise control strategy based on operating conditions. By monitoring the rate of change of engine speed, torque, and throttle stroke, it is possible to quickly determine whether the engine is in a transient condition, thus promptly activating a combustion noise control strategy adapted to the transient condition and improving control response speed. Using the rate of change of these three key parameters as the basis for judgment, compared to methods that determine operating conditions using a single parameter, this scheme can more accurately identify the engine's current operating state, avoiding improper combustion noise control caused by misjudgment of operating conditions.

[0031] In this embodiment, based on accurate operating condition identification, a more precise combustion noise control strategy can be implemented. For example, under steady-state conditions, the focus is on monitoring and correcting the combustion consistency between each piston cylinder; while under transient conditions, combustion noise is corrected based on the mapping relationship between the crankshaft speed change rate and the combustion noise change value, ensuring the flexibility and specificity of the control strategy. Simultaneously, by implementing specific combustion noise control strategies under different operating conditions, not only is the combustion noise of the engine effectively reduced under various operating states, thereby improving the overall NVH (Noise, Vibration, Harshness) performance of the vehicle and enhancing ride comfort, but the combustion noise control strategy can also be intelligently adjusted according to real-time changes in the engine's operating state.

[0032] In this embodiment, the method for determining the combustion consistency in all piston cylinders of the engine includes:

[0033] The crankshaft speed fluctuation rate of a piston cylinder is set as a preset speed fluctuation rate. If the ratio of the crankshaft speed fluctuation rate of any other piston cylinder to the preset speed fluctuation rate is within the preset ratio range, it is determined that the combustion in that piston cylinder is uniform. If the ratio of the crankshaft speed fluctuation rate of any other piston cylinder to the preset speed fluctuation rate exceeds the preset ratio range, combustion correction is required for that piston cylinder. The preset ratio range is 1 to 1.05.

[0034] Specifically, by setting a benchmark crankshaft speed fluctuation rate and comparing it with the fluctuation rates of other piston cylinders, a precise and quantified combustion consistency judgment standard is established. This achieves the goal of real-time monitoring and evaluation of the combustion state consistency of each cylinder in the engine, thus realizing the technical effect of intelligent diagnosis of combustion uniformity based on crankshaft speed fluctuation rate. Simultaneously, by continuously monitoring the engine crankshaft speed fluctuation rate, it is possible to accurately determine in real time whether the combustion state of each piston cylinder is consistent, providing an instant monitoring capability of the engine combustion process.

[0035] In this embodiment, a preset ratio range is set as the standard for judging combustion uniformity. Specifically, when the ratio of the crankshaft speed fluctuation rate of any piston cylinder to the preset speed fluctuation rate is within the range of 1 to 1.05, combustion is considered uniform. This achieves a quantitative assessment of combustion uniformity and improves the accuracy of combustion diagnosis. During engine operation, if the crankshaft speed fluctuation rate of a piston cylinder is found to exceed the preset ratio range, a combustion correction mechanism can be triggered in a timely manner. This avoids engine performance degradation and increased combustion noise caused by uneven combustion, enhancing engine operating stability and NVH performance. Simultaneously, the above control strategy can achieve intelligent diagnosis of combustion status based on real-time monitoring of crankshaft speed fluctuation rate, and feedback correction results through a closed-loop control mechanism, improving the intelligence level and response speed of the combustion noise control system.

[0036] In this embodiment, the method for establishing the mapping relationship between the crankshaft speed change rate and the combustion noise change value includes:

[0037] Step S21: Adjust the engine's operating parameters to change the engine's combustion state and collect the engine's combustion noise change value;

[0038] Step S22: Acquire the square wave signal of crankshaft speed, and process the transient speed change and transient speed change rate of the square wave signal to obtain the correspondence table between the crankshaft speed change value and the combustion noise change value under different operating parameters. The correspondence table is the mapping relationship between the crankshaft speed change rate and the combustion noise change value.

[0039] Specifically, by establishing a mapping relationship between the crankshaft speed change rate and the combustion noise change value, engine operating parameters are systematically adjusted. The relationship between combustion noise and crankshaft speed change rate is collected and analyzed, achieving the goal of constructing an accurate combustion noise prediction model. This realizes the technical effect of intelligent control of combustion noise based on crankshaft speed change rate, and solves the technical problems in traditional combustion noise control, such as the lack of quantitative analysis of the direct correlation between combustion noise and engine internal state, which makes it difficult to formulate noise control strategies, and the difficulty in adjusting combustion parameters in real time under dynamic operating conditions to match the optimal combustion noise control.

[0040] In this embodiment, a detailed mapping relationship is established by collecting combustion noise variations and crankshaft speed variation rates under different engine operating parameters. This allows the control system to accurately predict combustion noise levels based on real-time crankshaft speed variation rates. Simultaneously, based on this mapping relationship, the engine's combustion parameters (such as rail pressure and injection angle) can be intelligently adjusted to match the optimal combustion noise control target, achieving precise combustion state regulation even during transient engine operation. Furthermore, the mapping relationship allows the control system to instantly identify the combustion parameters requiring correction when combustion noise deviates from the normal range, reducing latency and improving the real-time performance and effectiveness of combustion noise control. Thus, by precisely controlling combustion parameters under different operating conditions, not only is combustion noise reduced, but also fuel efficiency degradation and power performance loss due to over-adjustment are avoided, achieving a harmonious balance between combustion performance, economy, and power.

[0041] Table 1. Mapping Relationship between Combustion Noise Variation Value and Crankshaft Speed ​​Variation Rate

[0042]

[0043] In this embodiment, the method for processing transient speed changes and transient speed change rates of square wave signals includes:

[0044] Step S23: According to formula n i =△α / (△t multiplied by 360) gives the transient speed change n i Where i = 1, 2, 3, ..., n, Δα is the angle difference between two pulses of the square wave signal, and Δt is the time difference between two pulses of the square wave signal;

[0045] Step S24: According to the formula △n=[max(n1,n2,n3…,n…]…] j )-min(n1,n2,n3…,n j )] / △α n The transient speed change rate Δn is obtained; where j=1,2,3…,i, Δα n denoted as the angle difference between the maximum and minimum rotational speeds within the window period of the square wave signal; where the transient rotational speed change rate Δn is the crankshaft speed change value.

[0046] Specifically, by accurately calculating and analyzing the transient changes in the crankshaft speed signal, and processing the transient speed changes and transient speed change rate of the square wave signal, the crankshaft speed fluctuation of the engine is quantified, the combustion noise source is accurately identified, and thus the technical effect of intelligent diagnosis and control of combustion noise based on the transient speed change rate is achieved.

[0047] In this embodiment, through formula n i The transient speed change n is calculated as Δα / (Δt multiplied by 360). i This accurately reflects the speed change of the engine crankshaft between any two pulses, providing a precise data basis for real-time monitoring of combustion noise. The formula is △n=[max(n1,n2,n3…,n…]. j )-min(n1,n2,n3…,n j )] / △α n The transient speed change rate Δn is used to calculate the rate of change between the maximum and minimum instantaneous crankshaft speed changes within a certain window period. This parameter quantifies the speed fluctuations during combustion and is a key indicator for combustion noise diagnosis. Thus, on the one hand, using the transient speed change rate Δn as the basis for identifying combustion noise sources allows for accurate judgment of the engine's combustion state, particularly for timely diagnosis of combustion noise changes, providing a clear direction for subsequent combustion parameter adjustments. On the other hand, based on the transient speed change rate Δn, the control system can dynamically adjust combustion parameters (such as rail pressure, injection angle, and fuel quantity), maintaining combustion noise within the optimal range even under transient operating conditions, achieving real-time intelligent control of combustion noise.

[0048] In this embodiment, the method for correcting combustion noise that exceeds a set noise range includes:

[0049] Based on the threshold range of the noise change value ΔS of combustion noise, adjust at least one of the following: throttle filter, common rail pressure, main injection angle, and pre-injection interval angle.

[0050] Specifically, the dynamic strategy adjustment method based on the combustion noise threshold range accurately identifies the engine combustion noise level and optimizes multiple combustion parameters accordingly. This effectively improves and controls combustion noise, enhances NVH performance, and achieves intelligent combustion regulation that balances power and fuel economy. Simultaneously, by dynamically adjusting key combustion parameters such as throttle filtering, common rail pressure, main injection angle, and pre-injection interval angle according to the combustion noise threshold range, precise control of different noise levels is achieved, effectively suppressing combustion noise and improving NVH performance.

[0051] In this embodiment, the method for adjusting at least one of the following—the circulating fuel supply, common rail pressure, main injection angle, and pre-injection interval angle—based on the threshold range of the combustion noise variation value ΔS includes:

[0052] If 0.5dBA≤△S<1.0dBA, then delay the main spray angle and increase the pre-spray interval angle;

[0053] If 1.0dBA≤△S<2.0dBA, then reduce the common rail pressure, delay the main injection angle, and increase the pre-injection interval angle;

[0054] If △S≥2.0dBA, then reduce the circulating fuel supply, reduce the common rail pressure, delay the main injection angle, and increase the pre-injection interval angle.

[0055] Specifically, through a graded response combustion noise control strategy, combustion parameters such as the circulating fuel supply, common rail pressure, main injection angle, and pre-injection interval angle are intelligently adjusted based on the threshold range of the combustion noise change value ΔS. This achieves dynamic optimization of the engine combustion state and effectively reduces combustion noise, thus realizing intelligent combustion regulation based on noise thresholds, balancing power, economy, and NVH performance. By setting different noise threshold ranges, precise identification and response to varying levels of combustion noise are achieved, ensuring the targetedness and effectiveness of the combustion noise control strategy. Based on the threshold range of the combustion noise change value ΔS, corresponding combustion parameter adjustments are automatically selected and implemented, such as delaying the main injection angle, increasing the pre-injection interval angle, reducing the common rail pressure, and even reducing the circulating fuel supply, achieving intelligent and adaptive combustion noise control. Simultaneously, the impact on engine power and economy is fully considered during combustion noise control. By selectively adjusting combustion parameters, noise reduction is achieved while avoiding adverse effects on engine performance.

[0056] In this embodiment, when the operating condition is transient, each piston cylinder undergoes a cycle as a judgment period. In one judgment period, if the proportion of the combustion noise change value ΔS exceeding 0.5dBA is greater than or equal to 50%, then at least one of the following is adjusted according to the threshold range of the noise change value ΔS with the highest proportion: throttle filter, common rail pressure, main injection angle, and pre-injection interval angle.

[0057] Specifically, under transient operating conditions, by periodically monitoring combustion noise and using a dynamic strategy adjustment mechanism, a cycle period is set for transient operating conditions, and the proportion exceeding a preset noise threshold of 0.5 dBA is statistically analyzed. This allows for real-time assessment of engine combustion noise levels and adaptive optimization of the combustion strategy, achieving intelligent combustion noise control based on transient operating condition characteristics. Simultaneously, using *a* cycles per piston cylinder as a judgment cycle, continuous monitoring of combustion noise ensures continuous assessment of noise levels, improving the timeliness and accuracy of noise control. By setting a noise over-limit ratio (exceeding 0.5 dBA), the system can automatically identify and statistically analyze the proportion of over-limit noise within a cycle. Once it reaches or exceeds 50%, the combustion strategy adjustment program is immediately initiated, improving the intelligence level of noise control. Furthermore, based on the threshold range of the combustion noise change value ΔS with the highest proportion within the cycle, combustion parameters such as throttle filtering, common rail pressure, main injection angle, and pre-injection interval angle are selectively adjusted, ensuring precise positioning of the combustion noise control strategy and avoiding inefficiency and increased energy consumption caused by blind adjustments.

[0058] In this embodiment, the engine combustion noise control method further includes:

[0059] If the combustion noise still exceeds the set noise range after the correction time reaches the preset time value, the engine will be controlled to issue a fault alarm signal.

[0060] Specifically, a time-based monitoring and fault early warning mechanism for combustion noise correction is adopted. By setting a correction time threshold, the combustion noise level is continuously monitored and responded to in a timely manner to ensure the effectiveness of combustion noise control and the safe operation of the engine. This achieves the technical effect of integrating combustion noise control and fault diagnosis based on time efficiency. Simultaneously, during the combustion noise correction process, by setting a preset time value, the control strategy can promptly determine whether the correction is effective, avoiding ineffective correction or excessively long correction times that could lead to persistently excessive combustion noise. This enhances the effectiveness and efficiency of combustion noise control. If the combustion noise still exceeds the set noise range after the correction time reaches the preset time value, the control system can immediately trigger a fault alarm, promptly notifying the driver and maintenance personnel. This prevents potential engine performance degradation or damage, ensuring driving safety and long-term stable engine operation.

[0061] In this embodiment, the aforementioned fault alarm mechanism enhances the engine's self-diagnostic function in combustion noise control, enabling it to identify problems in the combustion system or control strategy at the first moment, thus providing a basis for rapid and accurate fault location and troubleshooting.

[0062] In this embodiment, the method for selecting the window period of the square wave signal includes:

[0063] The engine's knock pressure signal is acquired, and the region in the square wave signal with the largest speed fluctuation and the largest combustion noise is taken as the window period.

[0064] Specifically, a window selection strategy based on knockdown signals and engine speed fluctuations accurately captures the stage during engine combustion where speed fluctuations are greatest and combustion noise is most significant, serving as the diagnostic and control window. This enhances the accuracy and effectiveness of combustion noise identification and control, achieving the technical effect of intelligent correlation between transient engine speed and combustion noise based on key combustion stages. Simultaneously, by analyzing knockdown signals, the region with the greatest speed fluctuations and most prominent combustion noise within the engine's operating cycle can be accurately identified—the so-called window—providing precise temporal positioning for subsequent combustion noise diagnosis and control.

[0065] In this embodiment, the explosion pressure signal is combined with engine speed fluctuations to identify the transient speed change characteristics at the peak of combustion noise, enhancing the accurate location of the combustion noise source and creating favorable conditions for targeted control of combustion noise. Simultaneously, by selecting the most sensitive window period during engine operation for combustion noise monitoring and analysis, the system can diagnose and control combustion noise more quickly and effectively, avoiding ineffective operations during non-critical stages and improving overall control efficiency.

[0066] As can be seen from the above description, the embodiments of the present invention achieve the following technical effects:

[0067] By monitoring and analyzing engine operating parameters in real time, the system accurately identifies engine operating conditions and adjusts combustion parameters accordingly, significantly improving the accuracy and response speed of engine combustion noise control. This effectively reduces engine combustion noise and enhances NVH performance while ensuring diesel engine power and economy, thus solving the problem of poor control effect in existing engine combustion noise control methods. Specifically, during engine operation, operating parameters, including but not limited to crankshaft speed, throttle opening, and torque, are acquired to provide basic data for subsequent combustion state identification and correction. Based on these parameters, the current engine operating condition is determined—either steady-state or transient. Under steady-state conditions, the combustion consistency of each piston cylinder is monitored. If uneven combustion is detected, combustion correction is immediately performed on the problematic piston cylinder to restore combustion consistency. Under transient conditions, the engine combustion noise level is assessed based on the mapping relationship between crankshaft speed change rate and combustion noise. If the combustion noise exceeds the set noise range, adjustments are made according to a preset correction strategy to reduce combustion noise. Meanwhile, considering the special characteristics of transient operating conditions, the reliability and effectiveness of the correction strategy are ensured by setting a reasonable combustion state correction threshold.

[0068] Obviously, the embodiments described above are merely some, not all, embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0069] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0070] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0071] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for controlling engine combustion noise, characterized in that, include: Step S1: Obtain the engine's operating status parameters; Step S2: Determine the engine's operating condition based on the operating status parameters. When the operating condition is a steady-state condition, determine the combustion consistency in all piston cylinders of the engine and correct the combustion of piston cylinders with uneven combustion based on the determination result. When the operating condition is a transient condition, determine the current combustion noise change value of the engine based on the mapping relationship between the crankshaft speed change rate and the combustion noise change value, and correct the combustion noise that exceeds the set noise range.

2. The engine combustion noise control method according to claim 1, characterized in that, The method for determining the engine's operating condition based on the aforementioned operating status parameters includes: If the rate of change of engine speed, the rate of change of torque, and the rate of change of throttle travel are all greater than zero, then the operating condition is determined to be a transient condition; otherwise, the operating condition is determined to be a steady-state condition.

3. The engine combustion noise control method according to claim 1, characterized in that, Methods for determining the combustion consistency across all pistons and cylinders in an engine include: A preset speed fluctuation rate is set for the crankshaft speed fluctuation rate of a piston cylinder. If the ratio of the crankshaft speed fluctuation rate of any other piston cylinder to the preset speed fluctuation rate is within a preset ratio range, then the combustion in that piston cylinder is considered uniform. If the ratio of the crankshaft speed fluctuation rate of any other piston cylinder to the preset speed fluctuation rate exceeds the preset ratio range, then combustion correction is required for that piston cylinder. The preset ratio range is 1 to 1.

05.

4. The engine combustion noise control method according to claim 1, characterized in that, Methods for establishing the mapping relationship between crankshaft speed change rate and combustion noise change value include: Step S21: Adjust the engine's operating parameters to change the engine's combustion state and collect the engine's combustion noise change value; Step S22: Acquire the square wave signal of crankshaft speed, and process the square wave signal for transient speed change and transient speed change rate to obtain a correspondence table between the crankshaft speed change value and the combustion noise change value under different operating parameters. The correspondence table is a mapping relationship between the crankshaft speed change rate and the combustion noise change value.

5. The engine combustion noise control method according to claim 4, characterized in that, The method for processing the transient speed change and transient speed change rate of the square wave signal includes: Step S23: According to formula n i =△α / (△t multiplied by 360) gives the transient speed change n i Where i = 1, 2, 3, ..., n, Δα is the angle difference between two pulses of the square wave signal, and Δt is the time difference between two pulses of the square wave signal; Step S24: According to the formula △n=[max(n1,n2,n3…,n…]…] j )-min(n1,n2,n3…,n j )] / △α n The transient speed change rate Δn is obtained; where j=1,2,3…,i, Δα n This represents the angle difference between the maximum and minimum rotational speeds within the window period of the square wave signal. Wherein, the transient speed change rate Δn is the crankshaft speed change value.

6. The engine combustion noise control method according to claim 1, characterized in that, Methods for correcting combustion noise that exceeds the set noise range include: Based on the threshold range of the noise change value ΔS of combustion noise, adjust at least one of the following: throttle filter, common rail pressure, main injection angle, and pre-injection interval angle.

7. The engine combustion noise control method according to claim 6, characterized in that, The method for adjusting at least one of the following—the circulating fuel supply, common rail pressure, main injection angle, and pre-injection interval angle—based on the threshold range of the combustion noise variation value ΔS includes: If 0.5dBA≤△S<1.0dBA, then delay the main spray angle and increase the pre-spray interval angle; If 1.0dBA≤△S<2.0dBA, then reduce the common rail pressure, delay the main injection angle, and increase the pre-injection interval angle; If △S≥2.0dBA, then reduce the circulating fuel supply, reduce the common rail pressure, delay the main injection angle, and increase the pre-injection interval angle.

8. The engine combustion noise control method according to claim 1, characterized in that, When the operating condition is transient, each piston cylinder undergoes a cycle as a judgment period. In one judgment period, if the proportion of the combustion noise change value ΔS exceeding 0.5 dBA is greater than or equal to 50%, then at least one of the following is adjusted according to the threshold range of the noise change value ΔS with the highest proportion: throttle filter, common rail pressure, main injection angle, and pre-injection interval angle.

9. The engine combustion noise control method according to claim 1, characterized in that, The engine combustion noise control method further includes: If the combustion noise still exceeds the set noise range after the correction time reaches the preset time value, the engine will be controlled to issue a fault alarm signal.

10. The engine combustion noise control method according to claim 5, characterized in that, The method for selecting the window period of the square wave signal includes: The engine's knock pressure signal is acquired, and the region in the square wave signal with the largest speed fluctuation and the largest combustion noise is taken as the window period.

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