An engine fuel injection method and system based on wall wetness risk suppression of PN emissions

Abstract

This invention discloses an engine fuel injection method and system for suppressing particulate emissions (PN) based on wall wetting risk, belonging to the field of engine technology. The method includes: collecting engine operation and fuel injection related parameters, including engine speed, engine load, fuel injection pressure, single fuel injection quantity, fuel injection start time, evaporation time between fuel injection end and ignition, and coolant temperature; constructing a wall wetting risk value for the current cycle based on the relevant parameters to characterize the probability of fuel wall wetting; comparing the wall wetting risk value with a preset risk threshold to determine the risk level of the current cycle; adaptively adjusting the fuel injection strategy according to the determined risk level; and executing the fuel injection operation of the current cycle according to the adjusted fuel injection strategy to suppress particulate emissions. The proposed solution quantifies wall wetting risk and adaptively adjusts the fuel injection strategy accordingly, effectively reducing particulate emissions.

Description

Technical Field

[0001] This invention relates to the field of engine technology, and specifically to an engine fuel injection method and system for suppressing PN emissions based on wall wetting risk. Background Technology

[0002] With increasingly stringent emission regulations, particulate number (PN) emission control in direct-injection gasoline engines has become a key focus of the industry. Existing research indicates that fuel wall impaction, liquid film formation, and wall wetting during fuel injection are among the main causes of increased PN emissions. To reduce PN emissions, current technologies primarily employ methods such as increasing injection pressure, optimizing injection timing, and using multi-stage injection strategies like dual-injection and triple-injection.

[0003] Specifically, one existing approach involves switching preset injection strategies under specific operating conditions such as load changes and acceleration; another approach reduces fuel adhesion to the piston crown and cylinder walls by adjusting the injection frequency and timing; and yet another approach reduces particulate matter increase caused by piston wetting by controlling the amount of direct injection fuel or using intake port injection in conjunction with direct injection. It is evident that existing technologies have recognized the close relationship between injection strategies, cylinder wall wetting, and particulate emissions.

[0004] However, existing technologies still have the following shortcomings: most solutions mainly rely on operating condition identification or fixed calibration tables to switch injection modes, which makes it difficult to directly reflect the actual risks of fuel impact on the wall, liquid film formation, and wall wetting in the current cycle, thus resulting in insufficient control targeting; although existing multi-injection solutions can reduce the single injection load, they usually do not uniformly incorporate factors such as injection pressure, single injection quantity, injection timing, evaporation time, and engine thermal state into the evaluation framework; especially under high-pressure or ultra-high-pressure injection conditions, although increased injection pressure is beneficial to atomization, it may also enhance spray penetration and wall interaction, and it is difficult to take into account the PN suppression requirements under different operating conditions by simply relying on fixed injection frequency or fixed switching logic.

[0005] Therefore, the existing technology lacks a control scheme that can quantify the risk of wall wetting and adaptively adjust the oil injection strategy accordingly. Summary of the Invention

[0006] To overcome the above-mentioned shortcomings, this invention proposes an engine fuel injection method and system for suppressing PN emissions based on wall wetting risk, which solves the problem that existing fuel injection control methods rely on operating condition identification or fixed calibration tables and cannot directly reflect the actual risk of wall wetting in the current cycle.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides an engine fuel injection method for suppressing PN emissions based on wall wetting risk, the method comprising:

[0009] Collect engine operating and fuel injection related parameters;

[0010] The wall wetting risk value for the current cycle is constructed based on the collected engine operation and fuel injection related parameters. The wall wetting risk value is used to characterize the possibility of fuel wall wetting.

[0011] The wall wetting risk value is compared with a preset risk threshold to determine the risk level of the current cycle;

[0012] Based on the determined risk level, the fuel injection strategy is adaptively adjusted; the fuel injection operation of the current cycle is executed according to the adjusted fuel injection strategy to suppress particulate emissions.

[0013] Preferably, the engine operation and fuel injection related parameters include engine speed, engine load, fuel injection pressure, single fuel injection quantity, fuel injection start time, evaporation time between fuel injection end and ignition, and coolant temperature.

[0014] Preferably, the construction of the wall wetting risk value for the current cycle includes: using a weighted summation method, multiplying the engine operation and fuel injection related parameters by their respective weighting coefficients and then summing them to obtain the wall wetting risk value.

[0015] Preferably, determining the wall wetting risk value includes: determining a basic risk value based on engine speed and load, and performing a product correction on the basic risk value based on the deviations of the remaining parameters in the engine operation and fuel injection related parameters relative to the baseline operating conditions.

[0016] Preferably, comparing the wall wetting risk value with a preset risk threshold to determine the risk level of the current cycle includes: determining the risk level as low risk, medium risk, or high risk based on the comparison result between the wall wetting risk value and the risk threshold.

[0017] Preferably, the adaptive adjustment of the fuel injection strategy based on the determined risk level includes: maintaining the basic fuel injection mode when the risk level is low; adjusting the fuel injection strategy to a multi-stage injection mode and redistributing the proportion of each injection when the risk level is medium; and further limiting the amount of fuel injected per injection based on the multi-stage injection mode and correcting the injection timing and injection interval when the risk level is high. The multi-stage injection mode includes a dual-injection mode or a triple-injection mode. The dual-injection mode includes pre-injection and main injection. The triple-injection mode includes a first pre-injection, a second pre-injection, and main injection. The redistribution of the proportion of each injection includes determining the fuel quantity proportion of each injection based on the magnitude of the wall wetting risk value.

[0018] Preferably, the correction of the injection timing and injection interval includes: when the risk level is determined to be high, advancing the start time of the main injection relative to the basic injection mode and extending the interval between adjacent injections.

[0019] Preferably, the adaptive fuel injection strategy further includes: when the total fuel injection demand is fixed, limiting the amount of fuel injected in a single injection and distributing it in multiple injections, so that the amount of fuel injected in a single injection does not exceed a preset upper limit value for the amount of fuel injected in a single injection; the upper limit value for the amount of fuel injected in a single injection is dynamically determined based on the fuel injection pressure and the coolant temperature.

[0020] Preferably, after executing the current cycle of fuel injection operation according to the adjusted fuel injection strategy, the method further includes: collecting engine combustion state parameters after executing the current cycle of fuel injection operation; comparing the engine combustion state parameters with a preset normal operating range; and correcting the calculation parameters of the wall wetting risk value or the adjustment range of the fuel injection strategy when the engine combustion state parameters exceed the normal operating range; wherein the engine combustion state parameters include combustion noise, torque fluctuation and exhaust temperature.

[0021] Secondly, the present invention provides an engine fuel injection system for suppressing PN emissions based on wall wetting risk, the system comprising:

[0022] The parameter acquisition module is used to collect engine operation and fuel injection related parameters;

[0023] The module is used to construct the wall wetting risk value for the current cycle based on the collected engine operation and fuel injection related parameters. The wall wetting risk value is used to characterize the possibility of fuel wall wetting.

[0024] The risk level determination module is used to compare the wall wetting risk value with a preset risk threshold to determine the risk level of the current cycle.

[0025] The strategy adjustment module is used to adaptively adjust the fuel injection strategy according to the determined risk level; and execute the fuel injection operation of the current cycle according to the adjusted fuel injection strategy to suppress particulate emissions.

[0026] Compared with the closest prior art, the present invention has the following beneficial effects:

[0027] This invention proposes an engine fuel injection method and system for suppressing particulate matter (PN) emissions based on wall wetting risk. This method more directly characterizes fuel wall impaction, liquid film formation, and wall wetting tendency within the current cycle, improving the accuracy of fuel injection strategy adjustment. By constructing a wall wetting risk value, this invention integrates factors such as injection pressure, single injection quantity, injection timing, evaporation conditions, and engine operating status into an evaluation framework, making the control basis closer to the physical root causes of PN generation. It can adaptively adjust injection parameters based on wall wetting risk, reducing PN emissions caused by localized over-richness and wall adhesion. This invention dynamically adjusts the number of injections, the proportion of each injection, the injection timing, and the injection interval according to the risk level, realizing a shift from a condition-driven to a risk-driven control mode.

[0028] This invention can simultaneously improve atomization and suppress the risk of wall collision under high-pressure or ultra-high-pressure injection conditions, thereby enhancing the adaptability of the fuel injection strategy under different operating conditions.

[0029] This invention, by dynamically adjusting the weighting coefficient and the upper limit of the single injection quantity, effectively suppresses wall wetting caused by enhanced spray penetration while improving atomization through high-pressure injection. Furthermore, it can be implemented on existing direct injection systems without relying on additional complex hardware, thus reducing system complexity and improving the feasibility of engineering applications.

[0030] While suppressing PN emissions, this invention also helps to balance engine torque output, combustion stability, and ease of control. Through a feedback correction step, this invention can achieve a balanced optimization between suppressing PN emissions and ensuring normal engine operation. Attached Figure Description

[0031] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0032] Figure 1 This is a flowchart of an engine fuel injection method for suppressing PN emissions based on wall wetting risk, provided in an embodiment of the present invention.

[0033] Figure 2 This is a schematic diagram of an engine fuel injection system for suppressing PN emissions based on wall wetting risk, provided in an embodiment of the present invention. Detailed Implementation

[0034] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of the present invention and are therefore merely examples, and should not be construed as limiting the scope of protection of the present invention.

[0035] It should be noted that, unless otherwise stated, the technical or scientific terms used in this application should have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0036] This invention provides an engine fuel injection method and system for suppressing PN emissions based on wall wetting risk. It is particularly applicable to the prediction of bolt preload decay, connection reliability evaluation, and structural optimization of magnesium alloy housings in new energy vehicle reducers under long-term high temperature and static load conditions.

[0037] The embodiments of the present invention will now be described with reference to the accompanying drawings.

[0038] Example 1: Please refer to Figure 1 Embodiment 1 of the present invention provides an engine fuel injection method for suppressing PN emissions based on wall wetting risk, the method specifically includes the following steps:

[0039] S101 collects engine operation and fuel injection related parameters;

[0040] S102 constructs the wall wetting risk value for the current cycle based on the collected engine operation and fuel injection related parameters. The wall wetting risk value is used to characterize the possibility of fuel wall wetting.

[0041] S103 compares the wall wetting risk value with a preset risk threshold to determine the risk level of the current cycle;

[0042] S104 adaptively adjusts the fuel injection strategy based on the determined risk level; and executes the fuel injection operation of the current cycle according to the adjusted fuel injection strategy to suppress particulate emissions.

[0043] In step S101 above, the engine operation and fuel injection related parameters include engine speed, engine load, fuel injection pressure, single fuel injection quantity, fuel injection start time, evaporation time between fuel injection end and ignition, and coolant temperature.

[0044] In step S102 above, the construction of the wall wetting risk value for the current cycle includes: using a weighted summation method, multiplying the engine operation and fuel injection related parameters by the corresponding weight coefficients and then summing them to obtain the wall wetting risk value.

[0045] Determining the wall wetting risk value includes:

[0046] The basic risk value is determined based on the engine speed and load, and then the basic risk value is corrected by multiplication based on the deviations of the other parameters in the engine operation and fuel injection related parameters relative to the baseline operating conditions.

[0047] In step S103 above, comparing the wall wetting risk value with a preset risk threshold to determine the risk level of the current cycle includes: determining the risk level as low risk level, medium risk level, or high risk level based on the comparison result between the wall wetting risk value and the risk threshold.

[0048] Step S104, adaptively adjusting the fuel injection strategy according to the determined risk level includes:

[0049] When the risk level is determined to be low, maintain the basic fuel injection mode;

[0050] When the risk level is determined to be medium, the fuel injection strategy will be adjusted to a multi-injection mode, and the proportion of each injection will be redistributed.

[0051] When the risk level is determined to be high, the amount of fuel injected in a single injection is further limited on the basis of the fractional injection mode, and the injection timing and injection interval are modified.

[0052] The multi-spray mode includes a dual-spray mode or a triple-spray mode. The dual-spray mode includes a pre-spray and a main spray. The triple-spray mode includes a first pre-spray, a second pre-spray, and a main spray.

[0053] The reallocation of fuel injection ratios for each injection includes determining the fuel quantity ratio for each injection based on the magnitude of the wall wetting risk value.

[0054] In the above embodiments, the correction of the injection timing and injection interval includes: when the risk level is determined to be high, advancing the start time of the main injection relative to the basic injection mode and extending the interval between adjacent injections.

[0055] In step S104, the adaptive fuel injection strategy further includes: when the total fuel injection demand is fixed, limiting the amount of fuel injected in a single injection and distributing it in multiple injections so that the amount of fuel injected in a single injection does not exceed a preset upper limit value for the amount of fuel injected in a single injection; the upper limit value for the amount of fuel injected in a single injection is dynamically determined based on the fuel injection pressure and the coolant temperature.

[0056] After executing the injection operation of the current cycle according to the adjusted injection strategy, step S104 further includes:

[0057] Collect engine combustion status parameters after executing the current fuel injection cycle;

[0058] The engine combustion state parameters are compared with a preset normal operating range;

[0059] When the engine combustion state parameters exceed the normal operating range, the calculation parameters of the wall wetting risk value or the adjustment range of the fuel injection strategy are corrected.

[0060] The engine combustion state parameters include combustion noise, torque fluctuation, and exhaust temperature.

[0061] Example 2: Based on the same inventive concept, Example 2 of this application also provides an engine fuel injection system for suppressing PN emissions based on wall wetting risk in an engine fuel injection method. The solution provided by this system is similar to the solution described in the above-described examples. Therefore, the specific limitations of one or more examples of an engine fuel injection system for suppressing PN emissions based on wall wetting risk provided below can be found in the above-described limitations of the engine fuel injection method for suppressing PN emissions based on wall wetting risk, and will not be repeated here.

[0062] In one embodiment, Embodiment 3 of the present invention provides an engine fuel injection system for suppressing PN emissions based on wall wetting risk, the system structure of which is as follows: Figure 2 As shown, it includes: a parameter acquisition module 210, a construction module 220, a level determination module 230, and a strategy adjustment module 240, wherein:

[0063] The parameter acquisition module 210 is used to acquire engine operation and fuel injection related parameters;

[0064] The construction module 220 is used to construct the wall wetting risk value of the current cycle based on the collected engine operation and fuel injection related parameters. The wall wetting risk value is used to characterize the possibility of fuel wall wetting.

[0065] The risk level determination module 230 is used to compare the wall wetting risk value with a preset risk threshold to determine the risk level of the current cycle.

[0066] The strategy adjustment module 240 is used to adaptively adjust the fuel injection strategy according to the determined risk level; and execute the fuel injection operation of the current cycle according to the adjusted fuel injection strategy to suppress particulate emissions.

[0067] like Figure 2 As shown, the oil spraying method of the present invention includes the following steps:

[0068] Step S101: Collect engine operation and fuel injection related parameters. The parameter acquisition module collects the following parameters from the engine electronic control unit or relevant sensors: engine speed n, fuel injection pressure. Engine load Single injection volume Fuel injection start time Evaporation time between the end of fuel injection and ignition and coolant temperature These parameters can be obtained from the sensors already on the engine, without the need for additional hardware.

[0069] Step S102: Construct the wall wetting risk value for the current cycle based on the collected parameters.

[0070] In the above embodiments, the construction module calculates the wall wetting risk value R using a weighted summation method. The calculation formula is as follows:

[0071] ;

[0072] In the formula, R represents the wall wetting risk value; Indicates the amount of fuel injected in a single injection; Indicates fuel injection pressure; Indicates the start time of fuel injection; Indicates the evaporation time between the end of fuel injection and ignition; This indicates the coolant temperature; n indicates the engine speed. This indicates the engine load. This risk value is used to comprehensively characterize the probability of fuel wall wetting within the current cycle; f={f1,f2...f7}, where f1 to f7 are the weighting coefficients for each parameter.

[0073] Step S103: Compare the wall wetting risk value with the preset risk threshold to determine the risk level of the current cycle.

[0074] The risk level determination module presets a first risk threshold R1 and a second risk threshold R2, where R1 < R2. Based on the comparison results of R with R1 and R2, the risk level is determined to be one of the following three:

[0075] When R≤R1, it is determined to be a low-risk level;

[0076] When R1 < R ≤ R2, it is determined to be a medium-risk level;

[0077] When R > R2, it is determined to be a high-risk level.

[0078] Step S104: Adaptively adjust the fuel injection strategy according to the determined risk level.

[0079] The strategy adjustment module executes different fuel injection strategies based on the risk level:

[0080] When the risk level is determined to be low, maintain the basic fuel injection mode, i.e., the single injection mode.

[0081] When the risk level is determined to be medium, the fuel injection strategy is adjusted to a multi-injection mode, and the proportion of each injection is reallocated. Multi-injection modes include dual-injection or triple-injection modes. Dual-injection mode includes pre-injection and main injection; triple-injection mode includes first pre-injection, second pre-injection, and main injection. When reallocating the proportion of each injection, the fuel quantity ratio for each injection is determined based on the magnitude of the wall wetting risk value R. For example, when R is near the lower limit of the medium risk level, the pre-injection ratio can be set to 10%~15%; when R is near the upper limit of the medium risk level, the pre-injection ratio can be set to 20%~30%.

[0082] When a high-risk level is identified, the single-injection volume is further limited based on the multi-injection mode, and the injection timing and interval are modified. Specifically, the start time of the main injection is advanced by a preset angle value (e.g., 5-15 degrees crankshaft angle) relative to the basic injection mode, and the interval between adjacent injections is extended by a preset time value (e.g., 0.5-2 milliseconds). Simultaneously, given a fixed total injection demand, by limiting the single-injection volume and allocating it in multiple injections, the single-injection volume of each injection is ensured to not exceed a preset upper limit. This preset upper limit is dynamically determined based on the injection pressure and coolant temperature: the higher the injection pressure or the lower the coolant temperature, the smaller the preset upper limit.

[0083] Step S104: Perform the current cycle's fuel injection operation according to the adjusted fuel injection strategy to suppress particulate emissions.

[0084] The strategy adjustment module sends the adjusted injection parameters to the injector and executes the injection operation for the current cycle.

[0085] After executing the injection operation according to the adjusted injection strategy, the system collects engine combustion state parameters after the current injection cycle, including combustion noise, torque fluctuation, and exhaust temperature. These parameters are compared with the preset normal operating range. When the engine combustion state parameters exceed the normal operating range, the calculation parameters for the wall wetting risk value (such as adjusting the weighting coefficients f1 to f7 or adjusting the injection strategy (such as reducing the injection timing advance or shortening the injection interval) are corrected to ensure that subsequent injection cycles suppress PN emissions while maintaining engine combustion stability and torque output.

[0086] Example 3: This example illustrates another method for determining the risk value of wall wetting.

[0087] Unlike the weighted summation method in Example 2, this example uses a product correction method to determine the wall wetting risk value. The specific steps are as follows:

[0088] First, based on the engine speed n and engine load, the basic risk value R is determined using a pre-calibrated baseline MAP diagram. base .

[0089] Then, based on the remaining parameters in the engine operation and fuel injection related parameters (fuel injection pressure) Single injection volume Fuel injection start time Evaporation time between the end of fuel injection and ignition and coolant temperature The deviation from the baseline operating condition corresponds to the basic risk value R. base Perform a product correction. The corrected wall wetting risk value R can be expressed as:

[0090] ;

[0091] In the formula, k1 to k5 are the correction coefficients for each parameter, and each correction coefficient is greater than 0. When a parameter is unfavorable to wall wetting control (such as excessively high injection pressure, excessively large single injection volume, excessively late injection start time SOI, excessively short evaporation time, or excessively low coolant temperature), the corresponding correction coefficient is greater than 1; otherwise, the correction coefficient is less than or equal to 1.

[0092] The advantages of the product correction method are: the basic risk value is determined by the engine's basic operating conditions (speed and load), reflecting the engine's inherent wall wetting tendency at different operating points; and each correction coefficient reflects the incremental influence of other parameters on wall wetting. This decoupling method facilitates calibration and debugging.

[0093] Example 4: This example provides a specific application scenario to further illustrate the technical effects of the present invention.

[0094] Under a certain medium-to-high load condition, the engine originally operated using a single-injection strategy. The parameter acquisition module detected: engine speed n = 2400 rpm, engine load Load = 0.65 (relative load), and injection pressure... =400 bar, single injection volume =18mg, injection start time SOI = 280 degrees before compression top dead center, evaporation time =1.2ms, coolant temperature The 85℃ construction module uses a weighted summation method to calculate the wall wetting risk value R=0.82. The level determination module presets R1=0.4 and R2=0.7. Since R=0.82>R2, it is determined to be a high-risk level.

[0095] The strategy adjustment module performs the following adjustments:

[0096] Adjust the single-spray mode to a three-spray mode: first pre-spray 8%, second pre-spray 12%, main spray 80%;

[0097] The start time of the main injection is advanced from 280 degrees to 272 degrees (8 degrees earlier crankshaft rotation).

[0098] The interval between the first pre-spray and the second pre-spray is set to 0.3ms, and the interval between the second pre-spray and the main spray is set to 1.2ms.

[0099] Based on an injection pressure of 400 bar and a coolant temperature of 85°C, determine the upper limit of the single injection quantity (m) from the table. max =10mg, the injection amounts for each injection were 1.44mg, 2.16mg, and 14.4mg, respectively, none of which exceeded m max ;

[0100] After performing the injection operation according to the adjusted three-injection strategy, the bench test results showed that PN emissions were reduced by about 65% compared with the original single-injection strategy, while the engine torque output and combustion stability were not significantly adversely affected.

[0101] Example 5:

[0102] This embodiment provides another specific application scenario, focusing on the role of the feedback correction step.

[0103] Under low-temperature operating conditions, the engine coolant temperature =30℃, fuel injection pressure =350 bar, other parameters are: engine speed n=1200 rpm, engine load Load=0.3, single injection quantity =1.2mg, injection start time SOI = 290 degrees before compression top dead center, evaporation time =1.5ms. The calculated R=0.65, classifying it as a medium-risk level.

[0104] The strategy adjustment module changed the basic injection mode to a dual-injection mode: 18% pre-injection and 82% main injection. After the injection operation, PN emissions were significantly reduced. However, combustion parameter monitoring revealed a slight increase in combustion noise, but it remained within an acceptable range. Torque fluctuations met requirements, and exhaust temperature was normal. Therefore, no feedback correction was needed, and the current adjustment strategy is effective.

[0105] Example 6: This example specifically describes the high-pressure injection conditions.

[0106] When the injection pressure At ≥350 bar, this invention improves the response sensitivity to high-pressure injection risks by dynamically adjusting the weighting coefficients. Specifically, under a weighted summation method, the injection pressure parameters... The weighting coefficient f2 is greater under high-pressure injection conditions than under low-pressure injection conditions. For example, when the injection pressure... When the bar is 200 bar, f2 = 0.1. When the bar is 400 bar, f² = 0.35; when =500 bar, f2=0.5; Through this design, under high-pressure injection conditions, the increase in injection pressure will be reflected more quickly in the increase of wall wetting risk value R, thereby triggering suppression measures such as fractional injection, limiting the amount of single injection, and advancing the injection time more timely, so as to achieve synergistic optimization of "high-pressure injection to improve atomization" and "suppressing wall wetting".

[0107] The engine fuel injection method and system for suppressing PN emissions based on wall wetting risk provided by this invention can be implemented through software upgrades or control logic optimization on the basis of existing direct injection engine control systems, without the need for additional complex hardware. It has good industrial practicality and application value. This method can be widely applied to the engine control field of gasoline direct injection engines, especially high-pressure or ultra-high-pressure injection systems, and has significant practical implications for meeting increasingly stringent emission regulations.

[0108] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0109] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0110] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0111] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0112] The above are merely embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of the claims of the present invention pending approval.

Claims

1. An engine fuel injection method for suppressing PN emissions based on wall wetting risk, characterized in that, Includes the following steps: Collect engine operating and fuel injection related parameters; The wall wetting risk value for the current cycle is constructed based on the collected engine operation and fuel injection related parameters. The wall wetting risk value is used to characterize the possibility of fuel wall wetting. The wall wetting risk value is compared with a preset risk threshold to determine the risk level of the current cycle; The fuel injection strategy is adaptively adjusted based on the determined risk level. The current cycle's fuel injection operation will be executed according to the adjusted fuel injection strategy to suppress particulate emissions.

2. The engine fuel injection method according to claim 1, characterized in that, The engine operation and fuel injection related parameters include engine speed, engine load, fuel injection pressure, single fuel injection quantity, fuel injection start time, evaporation time between fuel injection end and ignition, and coolant temperature.

3. The engine fuel injection method according to claim 2, characterized in that, The method for constructing the wall wetting risk value for the current cycle includes: using a weighted summation method, multiplying the engine operation and fuel injection related parameters by their respective weighting coefficients and then summing them to obtain the wall wetting risk value.

4. The engine fuel injection method according to claim 2, characterized in that, Determining the wall wetting risk value includes: The basic risk value is determined based on the engine speed and load, and then the basic risk value is corrected by multiplication based on the deviations of the other parameters in the engine operation and fuel injection related parameters relative to the baseline operating conditions.

5. The engine fuel injection method according to claim 1, characterized in that, The step of comparing the wall wetting risk value with a preset risk threshold to determine the risk level of the current cycle includes: determining the risk level as low risk level, medium risk level, or high risk level based on the comparison result of the wall wetting risk value and the risk threshold.

6. The engine fuel injection method according to claim 5, characterized in that, The adaptive adjustment of the fuel injection strategy based on the determined risk level includes: When the risk level is determined to be low, maintain the basic fuel injection mode; When the risk level is determined to be medium, the fuel injection strategy will be adjusted to a multi-injection mode, and the proportion of each injection will be redistributed. When the risk level is determined to be high, the amount of fuel injected in a single injection is further limited on the basis of the fractional injection mode, and the injection timing and injection interval are modified. The multi-spray mode includes a dual-spray mode or a triple-spray mode. The dual-spray mode includes a pre-spray and a main spray. The triple-spray mode includes a first pre-spray, a second pre-spray, and a main spray. The reallocation of fuel injection ratios for each injection includes determining the fuel quantity ratio for each injection based on the magnitude of the wall wetting risk value.

7. The engine fuel injection method according to claim 6, characterized in that, The correction of the injection timing and injection interval includes: when the risk level is determined to be high, advancing the start time of the main injection relative to the basic injection mode and extending the interval between adjacent injections.

8. The engine fuel injection method according to claim 6, characterized in that, The adaptive fuel injection strategy further includes: when the total fuel injection demand is fixed, limiting the amount of fuel injected in a single injection and distributing it in multiple injections, so that the amount of fuel injected in a single injection does not exceed a preset upper limit value for the amount of fuel injected in a single injection; the upper limit value for the amount of fuel injected in a single injection is dynamically determined based on the fuel injection pressure and the coolant temperature.

9. The engine fuel injection method according to claim 1, characterized in that, After executing the current cycle's injection operation according to the adjusted injection strategy, it also includes: Collect engine combustion status parameters after executing the current fuel injection cycle; The engine combustion state parameters are compared with a preset normal operating range; When the engine combustion state parameters exceed the normal operating range, the calculation parameters of the wall wetting risk value or the adjustment range of the fuel injection strategy are corrected. The engine combustion state parameters include combustion noise, torque fluctuation, and exhaust temperature.

10. An engine fuel injection system for suppressing PN emissions based on wall wetting risk, characterized in that, The system includes: a parameter acquisition module, used to acquire engine operation and fuel injection related parameters; The module is used to construct the wall wetting risk value for the current cycle based on the collected engine operation and fuel injection related parameters. The wall wetting risk value is used to characterize the possibility of fuel wall wetting. The risk level determination module is used to compare the wall wetting risk value with a preset risk threshold to determine the risk level of the current cycle. The strategy adjustment module is used to adaptively adjust the fuel injection strategy according to the determined risk level; and execute the fuel injection operation of the current cycle according to the adjusted fuel injection strategy to suppress particulate emissions.

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