Engine control system early combustion prevention protection method

Abstract

The present application relates to a kind of engine control system early combustion prevention protection method, the method includes the following steps: when engine is operated in the executed area, execute the measure of reducing early combustion occurrence;The executed area is set to include the following steps: detect early combustion occurrence;After the occurrence of early combustion, according to early combustion point working condition index, with the value of each working condition index of the early combustion point as the midpoint of interval, the correction value set is interval half length, early combustion point working condition interval is set as early combustion occurrence region;After the occurrence of early combustion, with the maximum value in the end value of each early combustion point working condition interval as boundary to determine new early combustion occurrence region;After determining as multiple early combustion, calibration early combustion occurrence region is executed area.Compared with prior art, the present application has the advantages of automatic identification easy early combustion region control and the like.

Description

Technical Field

[0001] This invention relates to the field of engine protection and control, and in particular to a method for preventing and protecting against pre-ignition in an engine control system. Background Technology

[0002] Pre-ignition refers to the phenomenon where the air-fuel mixture is ignited by a hot spot in the combustion chamber before the spark plug fires, resulting in significantly higher pressure than normal combustion. This leads to knocking sounds, power loss, and engine overheating. While mild pre-ignition may not cause serious harm, severe pre-ignition can result in severe knocking and significant engine damage.

[0003] To fundamentally suppress pre-ignition, one should start with engine design, optimizing the engine's intake system and combustion chamber to improve combustion conditions. However, if the engine design is already fixed and pre-ignition is only discovered during vehicle matching, then the only solution is to address the issue through electronic fuel injection control strategies.

[0004] Chinese patent CN202110919790.3 discloses a method and related equipment for monitoring engine pre-ignition. The method includes: counting the number of pre-ignitions in each cylinder of the engine to obtain a first pre-ignition count and a second pre-ignition count, wherein the first pre-ignition count is the number of pre-ignitions occurring in the cylinder within one life cycle, and the second pre-ignition count is the number of pre-ignitions occurring in the cylinder within the current counting cycle; determining the pre-ignition phenomenon level of the engine based on the first pre-ignition count; and performing torque limiting control on the engine according to the pre-ignition phenomenon level and the second pre-ignition count. Existing technology simply implements remedial measures only after the number of pre-ignitions in a single cylinder exceeds the limit. The number of pre-ignitions varies depending on the engine's operating conditions. This method cannot meet the complex real-world conditions, has a control lag, and cannot prevent pre-ignition.

[0005] Current control strategies primarily involve short-term measures to reduce pre-ignition after it is detected, aiming to minimize the damage caused by the initial pre-ignition to the engine. Existing methods cannot prevent future pre-ignitions, nor can they automatically identify and preventatively control operating conditions prone to pre-ignition. Summary of the Invention

[0006] The purpose of this invention is to overcome the defects of the prior art and provide a method for preventing and protecting against pre-ignition in engine control systems.

[0007] The objective of this invention can be achieved through the following technical solutions:

[0008] This invention provides a method for preventing and protecting against pre-ignition in an engine control system, the method comprising the following steps:

[0009] When the engine is operating in the target area, measures are taken to reduce pre-ignition.

[0010] Setting the region to be executed includes the following steps:

[0011] Detecting pre-ignition;

[0012] After a pre-ignition occurs, based on the pre-ignition point operating condition index, the value of each operating condition index at the pre-ignition point is taken as the midpoint of the interval, and the set correction value is half the length of the interval. The pre-ignition point operating condition interval is then set as the pre-ignition occurrence area.

[0013] After multiple premature ignitions, the new premature ignition zone is determined by the maximum value among the end values ​​of each premature ignition point condition interval.

[0014] Once a case is determined to be a frequent occurrence of pre-ignition, the area where the pre-ignition occurs is designated as the area to be subject to enforcement.

[0015] As a preferred technical solution, the determination step for multiple premature combustion includes:

[0016] A pre-ignition counter is set, which decreases by 1 for each cycle, where one cycle is one engine ignition event.

[0017] Detecting pre-ignition;

[0018] The pre-ignition count increases by a set value whenever pre-ignition is detected;

[0019] When the pre-ignition count exceeds the set threshold, it is determined to be a case of multiple pre-ignitions.

[0020] As a preferred technical solution, when the detonation angle or the average detonation angle is detected to be greater than the set angle threshold, the threshold for pre-ignition counting is changed.

[0021] As a preferred technical solution, the modified pre-ignition count threshold is less than the set value for increasing the pre-ignition count once.

[0022] As a preferred technical solution, when the pre-ignition count decays to zero, the determination of multiple pre-ignitions is lifted.

[0023] As a preferred technical solution, the pre-ignition point operating condition indicators include engine speed and load.

[0024] As a preferred technical solution, the measures to reduce pre-ignition include one or more of the following measures:

[0025] Reduce the air-fuel ratio, or enrich the air-fuel ratio;

[0026] Reduce VVT ​​overlap angle;

[0027] Limit torque output;

[0028] Exit the scavenging process.

[0029] As a preferred technical solution, the time for implementing measures to reduce pre-ignition is set according to requirements.

[0030] As a preferred technical solution, once the set mileage is met, the measures to reduce pre-ignition are discontinued.

[0031] As a preferred technical solution, the measures to reduce pre-ignition are discontinued after the key is turned off and the power is turned off.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] 1) This invention identifies areas where pre-ignition occurs and controls the pre-ignition in high-risk areas to effectively prevent and reduce the probability of pre-ignition, thus protecting the engine.

[0034] 2) After detecting a large knock in the engine, the present invention can adjust the counter limit, reduce the system's tolerance to pre-ignition, and better protect the engine.

[0035] 3) By setting a reasonable execution area, this invention minimizes the impact of implementing measures to reduce pre-ignition on driving. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the process of the present invention;

[0037] Figure 2 This is a schematic diagram illustrating the determination of multiple pre-ignition events according to the present invention;

[0038] Figure 3 This is a schematic diagram showing the execution area of ​​the present invention. Detailed Implementation

[0039] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0040] As one embodiment of the present invention, a method for preventing and protecting engine control system from pre-ignition is provided. When pre-ignition is detected and certain conditions are met, the system automatically identifies and records the operating point. When the engine is running in the operating point area, it will allow a certain period of time to enrich the air-fuel ratio, reduce torque, and reduce the overlap angle of VVT in order to reduce the frequency of pre-ignition. This time can be set by the calibration personnel according to the requirements.

[0041] S1 as Figure 2 As shown, when a pre-ignition is detected by the pre-ignition monitoring device, the system will calculate a counter 1 and increment it by a certain value, such as 12,000 counts. This value can be calibrated. The count will gradually decrease by 1 count with the engine ignition event as the cycle. If a pre-ignition occurs again, the count will be increased by another 12,000 counts. When the count of the counter is greater than a certain calibrable limit, for example, the limit below is set to be greater than 12,000 but less than 24,000, then more than or equal to 2 pre-ignitions will be judged as multiple pre-ignitions, and the continuous multiple pre-ignition flag will be set.

[0042] S2 as Figure 3 As shown, after multiple pre-ignitions occur, enrichment, torque limiting, and reduction of VVT overlap angle will be implemented. These measures will change the engine operating characteristics and thus affect normal driving. To minimize the impact, it is desirable to reduce the affected engine operating area as much as possible. After the first pre-ignition occurs, the system automatically records the pre-ignition point and the area where it occurs. If the pre-ignition point occurs at 1600 rpm and the load at which it occurs is 1800 IMEP, then the system will record a grid area of ​​1600 rpm ± 100 rpm (calibrable at 100 rpm) and 1800 IMEP ± 100 IMEP (calibrable at 100 IMEP) (grid 1). If a second pre-ignition occurs, and the area where the pre-ignition occurs is 2000 rpm and the load is 2000 IMEP, then after this pre-ignition, the recorded area expands to a region of 1500 rpm to 2100 rpm and a load of 1700 IMEP to 2100 IMEP. At this point, after the multiple pre-ignition setting is activated, this area becomes the area to be affected.

[0043] The operation of the S3 area will be performed as follows to reduce pre-ignition. All of the following measures can be specified for implementation or disabled:

[0044] ① Reduce the air-fuel ratio, or enrich the air-fuel ratio;

[0045] ②Reduce VVT ​​overlap angle;

[0046] ③Limited torque;

[0047] ④ Exit the scavenging process.

[0048] The exit conditions for S4's regional measures are: meeting a certain mileage (which can be calibrated), or turning off the key and powering off.

[0049] For products containing inferior fuel, which can cause significant knocking and increase the likelihood of pre-ignition, the system uses the knocking angle of the ignition timing to determine the cause. If the knocking angle or the calculated average angle exceeds a certain value, the limit of the aforementioned timer can be set separately. For example, it can be set so that the condition is reset and the aforementioned measures are executed as soon as pre-ignition is detected.

[0050] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A method for preventing and protecting against pre-ignition in an engine control system, characterized in that, The method includes the following steps: When the engine is operating in the target area, measures are taken to reduce pre-ignition. Setting the region to be executed includes the following steps: Detecting pre-ignition; After a pre-ignition occurs, based on the pre-ignition point operating condition index, the value of each operating condition index at the pre-ignition point is taken as the midpoint of the interval, and the set correction value is half the length of the interval. The pre-ignition point operating condition interval is then set as the pre-ignition occurrence area. After multiple premature ignitions, the new premature ignition zone is determined by the maximum value among the end values ​​of each premature ignition point condition interval. After determining that multiple premature ignitions have occurred, the area where the premature ignitions occurred is designated as the area to be executed. The determination steps for multiple premature ignitions include: A pre-ignition counter is set, which decreases by 1 for each cycle, where one cycle is one engine ignition event. Detecting pre-ignition; The pre-ignition count increases by a set value whenever pre-ignition is detected; If the pre-ignition count exceeds a set threshold, it is determined to be a case of multiple pre-ignitions. When the detected detonation angle or the average detonation angle is greater than the set angle threshold, the threshold for pre-ignition counting is changed; the changed pre-ignition counting threshold is less than the set value for each pre-ignition count increase.

2. The method for preventing and protecting against pre-ignition in an engine control system according to claim 1, characterized in that, When the pre-ignition count decays to zero, the multiple pre-ignition determination is lifted.

3. The method for preventing and protecting against pre-ignition in an engine control system according to claim 1, characterized in that, The pre-ignition point operating condition indicators include engine speed and load.

4. The method for preventing and protecting against pre-ignition in an engine control system according to claim 1, characterized in that, The measures to reduce the occurrence of pre-ignition include one or more of the following: Decrease the air-fuel ratio, or enrich the air-fuel ratio; Reduce VVT ​​overlap angle; Limit torque output; Exit the scavenging process.

5. The method for preventing and protecting against pre-ignition in an engine control system according to claim 1, characterized in that, The timing for implementing measures to reduce pre-ignition is set according to requirements.

6. The method for preventing and protecting against pre-ignition in an engine control system according to claim 1, characterized in that, Once the set mileage is met, the measures to reduce pre-ignition will be discontinued.

7. The method for preventing and protecting against pre-ignition in an engine control system according to claim 1, characterized in that, After turning off the key and powering off, exit the measures to reduce pre-ignition.

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