Optimization method and device for judging residual exhaust gas causing gasoline engine idle speed vibration

Abstract

The present application relates to the technical field of engine control, in particular to a judgment optimization method and device for residual exhaust gas causing gasoline engine idle speed jitter. Idle speed jitter information is collected and it is judged whether it meets the condition of gasoline engine idle speed jitter caused by combustion instability, if yes, it is judged whether the idle speed jitter is caused by residual exhaust gas according to the gasoline in-cylinder pressure characteristic curve and the maximum peak angle of explosion pressure, if yes, debugging is carried out by increasing the intake pressure of gasoline engine and synchronously retarding the ignition angle, and the optimization process is realized. The present application discriminates the type of idle speed jitter caused by combustion instability, analyzes the cylinder pressure characteristic curve, if the cylinder combustion speed of a gasoline cylinder presents the alternating phenomenon of "low-high-low-high", it can be judged that the residual exhaust gas amount is the key factor affecting the jitter, based on which debugging can be carried out by increasing the intake pressure and synchronously retarding the ignition angle, the judgment optimization method is simple, and the period of consumption is short.

Description

Technical Field

[0001] This invention relates to the field of engine control technology, and in particular to a method and apparatus for judging and optimizing gasoline engine idling vibration caused by residual exhaust gas. Background Technology

[0002] In the development, design, and testing of engine products, NVH performance is a crucial attribute requirement. During the idling process of gasoline engines, due to the relatively low engine load and the difficulty in controlling combustion uniformity, vibration problems often occur. Many factors contribute to idling vibration. At the source, improper fuel injection angles leading to uneven air-fuel mixtures, low spark plug energy resulting in slow flame propagation, excessively delayed ignition angles causing low combustion efficiency, improper ignition angle reserve release slopes leading to large differences in power output between cycles, unstable accessory loads, and large amounts of residual exhaust gas at idle all contribute to unstable combustion excitation. On the path, the main approach involves frequency avoidance requirements for the mounting system and engine excitation to reduce system sensitivity. Currently, automakers conduct frequency sweep tests on fuel injection angles to comprehensively evaluate combustion stability and emissions indicators. Ignition angle adjustment and accessory load calibration are also common tuning methods. However, due to the high complexity of testing, the influence of residual exhaust gas volume is often overlooked.

[0003] In the existing technology, the method for determining whether residual exhaust gas is a key factor is relatively complex, with few optimization methods. It requires the use of resistance thermometers with small time constants, modification of exhaust manifolds, and connection of relevant equipment to complete the test of residual exhaust gas, which is time-consuming and time-consuming. Summary of the Invention

[0004] The present invention aims to at least improve one of the technical problems existing in the prior art. To this end, the present invention proposes an optimized method and apparatus for judging the idling vibration of gasoline engines caused by residual exhaust gas.

[0005] The method for determining and optimizing gasoline engine idling vibration caused by residual exhaust gas according to a first aspect of the present invention includes the following:

[0006] Step S100: Define the type of idling vibration, including irregular vibration, half-order continuous vibration, first-order continuous vibration and second-order continuous vibration;

[0007] Step S200: Collect idling vibration information and determine whether it meets the conditions for gasoline engine idling vibration caused by combustion instability. If yes, proceed to step S300; otherwise, proceed to step S700.

[0008] Step S300: Verify whether the combustion in the gasoline cylinder is stable. If it is stable, proceed to step S200. If it is unstable, proceed to step S400. Specifically, construct an optimized scenario for judging the idling vibration of the gasoline engine caused by residual exhaust gas. This includes the installation of sensor equipment, removing the original spark plugs of the gasoline engine, installing a spark plug-type cylinder pressure sensor, leading out a signal line from the crankshaft position sensor, connecting it to the combustion analyzer, obtaining the crankshaft speed and position signals, and reading the coefficient of variation data of the net indicated mean effective pressure in a single cycle in the gasoline cylinder through the combustion analyzer.

[0009] Step S400: Online signal acquisition and analysis. Using a combustion analyzer, the cylinder pressure characteristic curve of gasoline under idling conditions is monitored in real time. The analysis is performed based on the cylinder pressure characteristic curve of gasoline under idling conditions to observe the combustion lag in each gasoline cylinder and read the maximum knock pressure peak angle.

[0010] Step S500: Determine and determine whether the idling vibration is caused by residual exhaust gas. Analyze the cylinder pressure characteristic curve and the peak angle of the maximum knock pressure to determine whether the idling vibration is caused by residual exhaust gas. The specific judgment criteria are whether there is gasoline cylinder combustion lag in the cylinder pressure characteristic curve and whether the gasoline cylinder combustion speed shows an alternating phenomenon between low and high. If yes, proceed to step S600; otherwise, proceed to step S700.

[0011] Step S600: Perform optimization operation by increasing the intake pressure of the gasoline engine and adjusting the synchronous push-back ignition angle to optimize the idling vibration of the gasoline engine caused by residual exhaust gas.

[0012] Step S700: The optimization process for gasoline engine idling vibration caused by residual exhaust gas is completed.

[0013] The method for judging and optimizing gasoline engine idling vibration caused by residual exhaust gas according to an embodiment of the present invention identifies the type of idling vibration caused by combustion instability and analyzes the cylinder pressure characteristic curve. If the cylinder combustion speed of a certain gasoline cylinder shows an alternating phenomenon of "low-high-low-high", it can be determined that the amount of residual exhaust gas is the key factor affecting the vibration. Based on this, the compression pressure can be increased and the ignition angle can be adjusted simultaneously by increasing the intake pressure and simultaneously pushing back the ignition angle to increase the compression pressure and increase the reserve torque, thereby reducing the proportion of residual exhaust gas. The judgment and optimization method is simple, has a short cycle, and solves the industry's idling vibration problem.

[0014] In one possible implementation of the first aspect, step S200, collecting the type of idling vibration and determining whether it meets the condition of gasoline engine idling vibration caused by residual exhaust gas, includes the following steps:

[0015] Step S210: Evaluate the collected idling vibration characteristics based on the vehicle's idling condition.

[0016] Step S220: Determine whether it meets the second-order continuous vibration type. If not, it meets the condition of gasoline engine idling vibration caused by combustion instability.

[0017] In one possible implementation of the first aspect, the criterion for determining whether a vehicle meets the second-order continuous vibration type in step S220 is that the driver or passenger sitting in the driver's seat or the front passenger seat experiences numbness due to continuous vehicle vibration.

[0018] In one possible implementation of the first aspect, in step S300, the evaluation criterion for verifying whether the combustion in the gasoline cylinder is stable is: whether the coefficient of variation of the net indicated mean effective pressure in a single cycle is greater than 15%; if so, it indicates that the combustion in the gasoline cylinder is unstable.

[0019] In one possible implementation of the first aspect, in step S500, the evaluation criterion for whether there is gasoline cylinder combustion lag in the cylinder pressure characteristic curve is as follows: In one working cycle of a gasoline engine, under normal combustion conditions, each cylinder will have two pressure peaks. If the crankshaft angle corresponding to the later pressure peak is larger, it indicates that the combustion speed of the cylinder is slow and combustion lag occurs.

[0020] In one possible implementation of the first aspect, in step S400, the maximum burst pressure peak angle is the crankshaft angle corresponding to the subsequent pressure peak.

[0021] An optimization device for determining gasoline engine idling vibration caused by residual exhaust gas according to a second aspect of the present invention includes:

[0022] The definition module is used to define the type of idling vibration, including irregular vibration, half-order continuous vibration, first-order continuous vibration and second-order continuous vibration;

[0023] The filtering module is used to collect idling vibration information and determine whether it meets the conditions for gasoline engine idling vibration caused by combustion instability;

[0024] The verification module is used to verify whether the combustion inside the gasoline cylinder is stable.

[0025] The analysis module is used to analyze the cylinder pressure characteristic curve of gasoline under idling conditions, observe the combustion lag in each gasoline cylinder, and read the peak angle of the maximum knock pressure.

[0026] The judgment module is used to determine whether the idling vibration is caused by residual exhaust gas. It analyzes the cylinder pressure characteristic curve and the peak angle of the maximum knock pressure to determine whether the idling vibration is caused by residual exhaust gas.

[0027] The optimization module is used to perform optimization operations on idling vibration caused by residual exhaust gas. It achieves the optimization process for idling vibration caused by residual exhaust gas by adjusting the intake pressure of the gasoline engine and the synchronous push-back ignition angle.

[0028] In one possible implementation of the second aspect, the verification module specifically includes sensor device installation, removing the original spark plugs of the gasoline engine, installing a spark plug-type cylinder pressure sensor, leading out a signal line from the crankshaft position sensor, connecting it to a combustion analyzer, obtaining crankshaft speed and position signals, and verifying whether the combustion in the gasoline cylinder is stable by using the coefficient of variation data of the net indicated mean effective pressure in a single cycle of the gasoline cylinder read by the combustion analyzer.

[0029] In one possible implementation of the second aspect, the judgment module further includes an identification module for identifying whether there is gasoline cylinder combustion lag in the cylinder pressure characteristic curve and whether the gasoline cylinder combustion speed exhibits an alternating phenomenon between low and high.

[0030] According to a third aspect of the present invention, a computer storage medium thereon stores a computer program, wherein the computer program, when executed by a processor, implements the above-described electric vehicle energy recovery torque exit speed control method.

[0031] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0032] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a flowchart of an optimized method for judging gasoline engine idling vibration caused by residual exhaust gas, according to an embodiment of the present invention.

[0034] Figure 2 This is a cylinder pressure characteristic curve of a four-cylinder gasoline cylinder in a continuous cycle process according to an embodiment of the present invention;

[0035] Figure 3 This is a cylinder pressure characteristic curve of a four-cylinder gasoline cylinder in a continuous cycle process according to an embodiment of the present invention;

[0036] Figure 4 This is a cylinder pressure characteristic curve of a four-cylinder gasoline cylinder in the third stage of a continuous cycle process according to an embodiment of the present invention;

[0037] Figure 5 This is a cylinder pressure characteristic curve of a four-cylinder gasoline cylinder in the fourth stage of a continuous cycle process according to an embodiment of the present invention. Detailed Implementation

[0038] The embodiments of the present invention are described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit this application.

[0039] It should be noted that when a component is said to be "fixed to" another component, it can be directly attached to the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0041] The terms "first," "second," "third," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish different objects and not to describe a particular order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, it may include a series of steps or units, or optionally, steps or units not listed, or other steps or units inherent to these processes, methods, products, or devices.

[0042] The accompanying drawings show only the portions relevant to this application, not all of them. Before discussing exemplary embodiments in more detail, it should be noted that some exemplary embodiments are described as processes or methods depicted as flowcharts. Although the flowcharts describe operations (or steps) as sequential processes, many of these operations may be performed in parallel, concurrently, or simultaneously. Furthermore, the order of the operations may be rearranged. The process may be terminated when its operation is completed, but may also have additional steps not included in the drawings. The process may correspond to a method, function, procedure, subroutine, subprogram, etc.

[0043] The terms “component,” “module,” “system,” “unit,” etc., used in this specification are used to refer to computer-related entities, hardware, firmware, combinations of hardware and software, software, or software in execution. For example, a unit can be, but is not limited to, a process running on a processor, a processor, an object, an executable file, a thread of execution, a program, and / or distributed between two or more computers. Furthermore, these units can be executed from various computer-readable media on which various data structures are stored. Units can communicate, for example, via local and / or remote processes based on signals having one or more data packets (e.g., data from a second unit interacting with another unit between a local system, a distributed system, and / or a network; for example, the Internet interacting with other systems via signals).

[0044] Example 1

[0045] The method for determining and optimizing gasoline engine idling vibration caused by residual exhaust gas according to a first aspect of the present invention includes the following:

[0046] Step S100: Define the type of idling vibration, including irregular vibration, half-order continuous vibration, first-order continuous vibration and second-order continuous vibration;

[0047] Step S200: Collect idling vibration information and determine whether it meets the conditions for gasoline engine idling vibration caused by combustion instability. If yes, proceed to step S300; otherwise, proceed to step S700.

[0048] Step S300: Verify whether the combustion in the gasoline cylinder is stable. If it is stable, proceed to step S200. If it is unstable, proceed to step S400. Specifically, construct an optimized scenario for judging the idling vibration of the gasoline engine caused by residual exhaust gas. This includes the installation of sensor equipment, removing the original spark plugs of the gasoline engine, installing spark plug-type cylinder pressure sensors, leading out a signal line from the crankshaft position sensor, connecting it to the combustion analyzer, obtaining the crankshaft speed and position signals, and reading the coefficient of variation data of the net indicated mean effective pressure in a single cycle in the gasoline cylinder through the Kibox combustion analyzer.

[0049] Step S400: Online signal acquisition and analysis. Using a Kibox combustion analyzer, the cylinder pressure characteristic curve of gasoline under idling conditions is monitored in real time. The analysis is performed based on the cylinder pressure characteristic curve of gasoline under idling conditions to observe the combustion lag in each gasoline cylinder and read the peak angle of the maximum knock pressure.

[0050] Step S500: Determine whether the idling vibration is caused by residual exhaust gas. Analyze the gasoline cylinder pressure characteristic curve and the peak angle of maximum knock pressure to determine if the idling vibration is caused by residual exhaust gas.

[0051] The specific judgment principle is as follows: a large amount of residual exhaust gas in a certain cycle will cause combustion lag in that cycle. Combustion lag leads to a high exhaust temperature in that cycle, resulting in a low density of residual exhaust gas in the next cycle. Consequently, the amount of residual exhaust gas in the following cycle is small, the combustion speed increases, and normal combustion is achieved. This alternation of low and high combustion speeds within the same cylinder is a typical phenomenon of poor combustion quality caused by residual exhaust gas. It reflects the mechanism by which the amount of residual exhaust gas is affected by exhaust gas density and the mechanism by which flame speed is affected by the amount of residual exhaust gas.

[0052] The specific judgment criteria are whether there is gasoline cylinder combustion lag in the cylinder pressure characteristic curve and whether the gasoline cylinder combustion speed alternates between low and high. If yes, then proceed to step S600; otherwise, proceed to step S700.

[0053] Step S600 involves performing optimization. Since the proportion of residual exhaust gas at idle speed, under a fixed compression ratio, is mainly affected by the camshaft phase and intake pressure, the desired effect for the camshaft phase is to remove more exhaust gas after combustion to reduce the proportion of exhaust gas in the cylinder. However, since the VVT ​​is locked at idle, the camshaft phase is determined solely by hardware, making modification difficult. This invention optimizes the idle vibration of the gasoline engine caused by residual exhaust gas by increasing the intake pressure and simultaneously pushing back the ignition angle. Increasing the intake pressure improves the compression pressure, thereby reducing the proportion of residual exhaust gas. Considering that idle speed is based on speed control, the ignition angle needs to be pushed back simultaneously to increase reserve torque, requiring repeated adjustments.

[0054] Step S700: The optimization process for gasoline engine idling vibration caused by residual exhaust gas is completed.

[0055] The method for judging and optimizing gasoline engine idling vibration caused by residual exhaust gas according to an embodiment of the present invention identifies the type of idling vibration caused by combustion instability and analyzes the cylinder pressure characteristic curve. If the cylinder combustion speed of a certain gasoline cylinder shows an alternating phenomenon of "low-high-low-high", it can be determined that the amount of residual exhaust gas is the key factor affecting the vibration. Based on this, the compression pressure can be increased and the ignition angle can be adjusted simultaneously by increasing the intake pressure and simultaneously pushing back the ignition angle to increase the compression pressure and increase the reserve torque, thereby reducing the proportion of residual exhaust gas. The judgment and optimization method is simple, has a short cycle, and solves the industry's idling vibration problem.

[0056] It should be noted that in step S200, collecting idling vibration information and determining whether it meets the conditions for gasoline engine idling vibration caused by residual exhaust gas includes the following steps:

[0057] Step S210: Evaluate the collected idling vibration characteristics based on the vehicle's idling condition.

[0058] Step S220: Determine whether it meets the second-order continuous vibration type. If not, it meets the condition of gasoline engine idling vibration caused by combustion instability.

[0059] It should be noted that the criterion for determining whether a vehicle meets the second-order continuous vibration type in step S220 is that the driver or passenger sitting in the driver's seat or the front passenger seat experiences numbness due to continuous vehicle vibration.

[0060] It should be noted that in step S300, the evaluation criterion for verifying whether the combustion in the gasoline cylinder is stable is: whether the coefficient of variation of the net indicated mean effective pressure in a single cycle is greater than 15%. If so, it indicates that the combustion in the gasoline cylinder is unstable.

[0061] It should be noted that the alternating low and high combustion speed of the gasoline cylinder in step S500 is characterized by an alternating "low-high-low-high" combustion speed, meaning that the idling vibration of the gasoline engine is caused by residual exhaust gas. Specifically, taking a four-cylinder gasoline engine as an example, refer to... Figures 2 to 5 The image shows the cylinder pressure characteristic curves of a four-cylinder gasoline engine in four stages of a continuous cycle. Within these curves, four different curves (PCYL1-4, corresponding to the cylinder pressure characteristic curves of cylinders one through four) represent the cylinder pressure characteristic curves of each of the four cylinders. According to... Figures 2 to 5 As shown, the combustion speed in the gasoline cylinder exhibits an alternating pattern of "low-high-low-high," indicating that the idling vibration of the gasoline engine is caused by residual exhaust gas. The analysis is as follows: Under normal combustion conditions, the gasoline cylinder exhibits two peak values, such as... Figure 2 As shown, at the 0-degree crankshaft rotation position, there is a first peak value, which is the peak value of compression pressure, indicating the end of the compression stroke and the immediate start of the power stroke; as Figure 2 As shown, the second peak values ​​of cylinders two through four are generally within 90 degrees of crankshaft angle (cylinders three and four are around 70 degrees, and cylinder two is around 90 degrees), while the second peak value of cylinder one reaches around 150 degrees of crankshaft angle and is very small. This indicates that the gasoline engine exhibits slow combustion speed and combustion lag. Figure 3 As shown, the second peak value of cylinders one through four is generally within 90 degrees of crankshaft rotation, indicating that the gasoline cylinders have switched to normal combustion conditions at this point, and so on. Figure 4 and Figure 5 As shown, the gasoline engine exhibited slow combustion speed and combustion lag before returning to normal combustion. Therefore, a quantitative parameter can be selected to characterize the combustion speed: the crankshaft angle corresponding to the second pressure peak (ignition peak) in the cylinder pressure characteristic curve. A value within 100 degrees indicates a basically normal combustion speed, while a value exceeding 130 degrees indicates combustion lag. Figures 2 to 5The cylinder pressure characteristic curve of a gasoline cylinder in a continuous cycle shows that the combustion speed of the gasoline cylinder exhibits an alternating phenomenon of "low-high-low-high".

[0062] It should be noted that in step S500, the evaluation criterion for whether there is gasoline cylinder combustion lag in the cylinder pressure characteristic curve is as follows: In one working cycle of a gasoline engine, under normal combustion conditions, each cylinder will have two pressure peaks. If the crankshaft angle corresponding to the later pressure peak is larger, it indicates that the combustion speed of that cylinder is slow and there is lag.

[0063] It should be noted that in step S400, the maximum burst pressure peak angle is the crankshaft angle corresponding to the subsequent pressure peak.

[0064] The following is a specific example:

[0065] Testing was conducted on the idling vibration problem of a 2.3L gasoline engine. Using the method described in Example 1, the cylinder pressure characteristic curve was analyzed, revealing that the combustion speed followed an alternating pattern of "low-high-low-high." This led to the conclusion that residual exhaust gas volume was the key factor affecting the vibration. Through repeated adjustments, the intake pressure was increased, raising the compression pressure from 4.2 Bar to 4.8 Bar, and the ignition angle was shifted from 10° to approximately 7°, optimizing combustion stability. The subjective evaluation of the vibration improved by 0.25 points. Based on this demonstration, this invention proposes a rapid and efficient method for determining the influencing factor of residual exhaust gas volume, and also presents a feasible optimization approach, offering a new solution to idling vibration.

[0066] Example 2

[0067] This embodiment provides an optimization device for judging and addressing gasoline engine idling vibration caused by residual exhaust gas, including:

[0068] The definition module is used to define the type of idling vibration, including irregular vibration, half-order continuous vibration, first-order continuous vibration and second-order continuous vibration;

[0069] The filtering module is used to collect idling vibration information and determine whether it meets the conditions for gasoline engine idling vibration caused by combustion instability;

[0070] The verification module is used to verify whether the combustion in the gasoline cylinder is stable. Specifically, it constructs an optimized scenario for judging the idling vibration of the gasoline engine caused by residual exhaust gas. This includes the installation of sensor equipment, removing the original spark plugs of the gasoline engine, installing spark plug-type cylinder pressure sensors, leading out a signal line from the crankshaft position sensor, and connecting it to the combustion analyzer to obtain the crankshaft speed and position signals. The stability of the combustion in the gasoline cylinder is verified by the coefficient of variation data of the net indicated mean effective pressure in a single cycle of the gasoline cylinder read by the combustion analyzer.

[0071] The analysis module is used to analyze the cylinder pressure characteristic curve of gasoline under idling conditions, observe the combustion lag in each gasoline cylinder, and read the peak angle of the maximum knock pressure.

[0072] The judgment module is used to determine whether the idling vibration is caused by residual exhaust gas. It analyzes the cylinder pressure characteristic curve and the peak angle of the maximum knock pressure to determine whether the idling vibration is caused by residual exhaust gas.

[0073] The optimization module is used to perform optimization operations on idling vibration caused by residual exhaust gas. It achieves the optimization process for idling vibration caused by residual exhaust gas by adjusting the intake pressure of the gasoline engine and the synchronous push-back ignition angle.

[0074] It should be noted that the verification module specifically includes sensor equipment installation. The original spark plugs of the gasoline engine are removed, and a spark plug-type cylinder pressure sensor is installed. A signal line is led out from the crankshaft position sensor and connected to the combustion analyzer to obtain the crankshaft speed and position signals. The stability of combustion in the gasoline cylinder is verified by the coefficient of variation data of the net indicated mean effective pressure in a single cycle of gasoline cylinder read by the Kibox combustion analyzer.

[0075] It should be noted that the judgment module also includes an identification module, which is used to identify whether there is gasoline cylinder combustion lag in the cylinder pressure characteristic curve and whether the gasoline cylinder combustion speed alternates between low and high.

[0076] Example 3

[0077] This embodiment provides a computer storage medium storing a computer program, wherein the computer program, when executed by a processor, implements the above-described electric vehicle energy recovery torque exit speed control method.

[0078] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention.

[0079] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example.

[0080] Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. The reference to "embodiment" herein means that a specific feature, structure, or characteristic described in connection with an embodiment can be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily indicate the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0081] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. An optimized method for judging idling vibration in gasoline engines caused by residual exhaust gas, characterized in that, Includes the following: Step S100: Define the idling vibration type, including irregular vibration, half-order continuous vibration, first-order continuous vibration, and second-order continuous vibration. The standard for the second-order continuous vibration type is as follows: If a driver or passenger experiences numbness due to continuous vehicle vibration while sitting in the driver's or front passenger's seat, it is considered to be a second-order continuous vibration. Step S200: Collect idling vibration information and determine whether it meets the conditions for gasoline engine idling vibration caused by combustion instability. If yes, proceed to step S300; otherwise, proceed to step S700. Collecting idling vibration information and determining whether it meets the conditions for gasoline engine idling vibration caused by combustion instability includes the following steps: Step S210: Evaluate the collected idling vibration characteristics based on the vehicle's idling condition. Step S220: Determine whether it meets the second-order continuous vibration type. If not, it meets the condition of gasoline engine idling vibration caused by combustion instability. Step S300: Verify whether the combustion in the gasoline cylinder is stable. If it is stable, proceed to step S200. If it is unstable, proceed to step S400. Specifically, construct an optimized scenario for judging the idling vibration of the gasoline engine caused by residual exhaust gas. This includes the installation of sensor equipment, removing the original spark plugs of the gasoline engine, installing a spark plug-type cylinder pressure sensor, leading out a signal line from the crankshaft position sensor, connecting it to the combustion analyzer, obtaining the crankshaft speed and position signals, and reading the coefficient of variation data of the net indicated mean effective pressure in a single cycle in the gasoline cylinder through the combustion analyzer. Step S400: Online signal acquisition and analysis. Using a combustion analyzer, the cylinder pressure characteristic curve of gasoline under idling conditions is monitored in real time. The analysis is performed based on the cylinder pressure characteristic curve of gasoline under idling conditions to observe the combustion lag in each gasoline cylinder and read the maximum knock pressure peak angle. Step S500: Determine whether the idling vibration is caused by residual exhaust gas. Analyze the cylinder pressure characteristic curve and the peak angle of maximum knock pressure to determine if residual exhaust gas is causing the idling vibration. Specifically, the determination is based on whether there is gasoline combustion lag in the cylinder pressure characteristic curve, indicating an alternating low and high combustion speed. If yes, proceed to step S600; otherwise, proceed to step S700. The evaluation criteria for whether gasoline combustion lag exists in the cylinder pressure characteristic curve are as follows: In one working cycle of a gasoline engine, under normal combustion conditions, each cylinder will have two pressure peaks. If the crankshaft angle corresponding to the later pressure peak is larger, it indicates that the combustion speed of that cylinder is slow, resulting in combustion lag. Step S600: Perform optimization operation by increasing the intake pressure of the gasoline engine and adjusting the synchronous push-back ignition angle to optimize the idling vibration of the gasoline engine caused by residual exhaust gas. Step S700: The optimization process for gasoline engine idling vibration caused by residual exhaust gas is completed.

2. The method for determining and optimizing gasoline engine idling vibration caused by residual exhaust gas as described in claim 1, characterized in that, In step S300, the evaluation criterion for verifying whether the combustion in the gasoline cylinder is stable is: whether the coefficient of variation of the net indicated mean effective pressure in a single cycle is greater than 15%; if so, it indicates that the combustion in the gasoline cylinder is unstable.

3. The method for determining and optimizing gasoline engine idling vibration caused by residual exhaust gas according to claim 1, characterized in that, In step S400, the maximum burst pressure peak angle is the crankshaft angle corresponding to the subsequent pressure peak.

4. A device for judging and optimizing gasoline engine idling vibration caused by residual exhaust gas, characterized in that, To implement the judgment optimization method as described in any one of claims 1 to 3, comprising: The definition module is used to define the type of idling vibration, including irregular vibration, half-order continuous vibration, first-order continuous vibration, and second-order continuous vibration. The standard for the second-order continuous vibration type is as follows: If a driver or passenger experiences numbness due to continuous vehicle vibration while sitting in the driver's or front passenger's seat, it is considered to be a second-order continuous vibration. The filtering module is used to collect idling vibration information and determine whether it meets the conditions for gasoline engine idling vibration caused by combustion instability. Specifically, it includes: The evaluation of the idling vibration characteristics collected under vehicle idling conditions; Determine whether it meets the second-order continuous vibration type. If not, it meets the condition of gasoline engine idling vibration caused by combustion instability. The verification module is used to verify whether the combustion in the gasoline cylinder is stable. Specifically, it constructs an optimized scenario for judging the idling vibration of the gasoline engine caused by residual exhaust gas. This includes the installation of sensor equipment, removing the original spark plugs of the gasoline engine, installing spark plug-type cylinder pressure sensors, leading out a signal line from the crankshaft position sensor, connecting it to the combustion analyzer, obtaining the crankshaft speed and position signals, and reading the coefficient of variation data of the net indicated mean effective pressure in a single cycle in the gasoline cylinder through the combustion analyzer. The analysis module is used for online signal acquisition and analysis. Through the combustion analyzer, it monitors the cylinder pressure characteristic curve of gasoline under idling conditions in real time, analyzes the cylinder pressure characteristic curve of gasoline under idling conditions, observes the combustion lag in each gasoline cylinder, and reads the peak angle of the maximum knock pressure. The judgment module is used to determine whether idling vibration is caused by residual exhaust gas. It analyzes the in-cylinder pressure characteristic curve and the peak angle of maximum knock pressure to determine if residual exhaust gas is causing the idling vibration. Specifically, the judgment is based on whether there is gasoline combustion lag in the in-cylinder pressure characteristic curve, and whether the gasoline combustion speed alternates between low and high. The evaluation criteria for whether gasoline combustion lag exists in the in-cylinder pressure characteristic curve are as follows: In one working cycle of a gasoline engine, under normal combustion conditions, each cylinder will have two pressure peaks. If the crankshaft angle corresponding to the later pressure peak is larger, it indicates that the combustion speed of that cylinder is slow, resulting in combustion lag. The optimization module is used to perform optimization operations. It adjusts the gasoline engine's idling vibration caused by residual exhaust gas by increasing the gasoline engine's intake pressure and synchronously pushing back the ignition angle.

5. A computer storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the optimization method for judging gasoline engine idling vibration caused by residual exhaust gas as described in any one of claims 1 to 3.

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