Diesel engine oil mist concentration alarm control method and system based on multi-sensor fusion

Abstract

The application discloses a diesel engine oil mist concentration alarm control method and system based on multi-sensor fusion, relates to the technical field of oil mist detection, and comprises the following steps: synchronously collecting light scattering signals, light transmittance signals, detection cavity temperature and humidity, crankcase pressure, oil temperature and node position identifiers of each oil mist detection node, aligning the signals according to a unified sampling clock, and obtaining an oil mist concentration detection frame; converting the light scattering signals and the light transmittance signals in the oil mist concentration detection frame into same-direction oil mist response quantities, combining the crankcase pressure and the continuity of adjacent node responses, screening scattering fine reverse and transmittance same-direction changes, and obtaining a candidate oil mist mutation event sequence; and performing scattering and transmittance time difference checking on the candidate oil mist mutation event sequence. The application determines an oil mist arrival time by using a scattering leading time in a real oil mist particle concentration event, and improves early identification capability, interference elimination capability and fault positioning reliability of diesel engine oil mist alarm.

Description

Technical Field

[0001] This invention relates to the field of oil mist detection technology, and in particular to a method and system for alarm control of diesel engine oil mist concentration based on multi-sensor fusion. Background Technology

[0002] Oil mist is generated in various parts of a diesel engine during operation, including the crankcase, main bearing area, connecting rod bearing area, gear transmission area, and oil return chamber, due to factors such as lubricating oil atomization, bearing friction heating, and crankcase airflow pulsation. Current diesel engine oil mist concentration alarms typically rely on detection signals such as light scattering, light transmittance, temperature and humidity, pressure, and engine oil temperature to collect data on oil mist concentration changes at different detection points. The presence of oil mist risk is then determined based on concentration limits, alarm levels, or shutdown protection conditions. With increasing safety monitoring requirements for diesel engines, deploying multiple oil mist detection nodes, simultaneously acquiring multi-source sensor signals, and implementing graded alarms for oil mist concentration changes have become important technological directions in the field of diesel engine oil mist monitoring.

[0003] However, the internal environment for oil mist detection in diesel engines is complex. Fine oil mist particles often initially exhibit localized enhancement or slight reversal of the light scattering signal, followed by a continuous attenuation of the light transmittance signal after oil mist accumulation. Water vapor condensation, crankcase pressure shocks, and airflow pulsations can also cause similar optical fluctuations. If alarms are based solely on a single concentration limit or a single optical channel, water vapor condensation and pressure disturbances are easily misjudged as oil mist anomalies, or the evolutionary characteristics of early fine oil mist particles are ignored. Furthermore, the arrival sequence of oil mist at multiple detection nodes is not fully utilized, making it difficult to accurately correspond alarm results to the source of the anomaly and the direction of oil mist diffusion, thus affecting the accuracy and traceability of diesel engine oil mist alarms. Summary of the Invention

[0004] In view of the aforementioned existing problems, the present invention is proposed.

[0005] Therefore, this invention provides a diesel engine oil mist concentration alarm control method based on multi-sensor fusion to solve the problem that it is difficult to distinguish real oil mist events from water vapor condensation and airflow disturbances in diesel engine oil mist detection and to accurately locate the source.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0007] In a first aspect, the present invention provides a diesel engine oil mist concentration alarm control method based on multi-sensor fusion, which includes,

[0008] Simultaneously collect light scattering signals, light transmittance signals, detection chamber temperature and humidity, crankcase pressure, engine oil temperature, and node position markers at each oil mist detection node, and align them according to a unified sampling clock to obtain an oil mist concentration detection frame;

[0009] The light scattering signal and light transmittance signal in the oil mist concentration detection frame are converted into the same-direction oil mist response quantity. Combined with the crankcase pressure and the continuity of the response of adjacent nodes, the subtle reversal of scattering and the same-direction change of transmittance are screened to obtain the candidate oil mist mutation event sequence.

[0010] The candidate oil mist mutation event sequence is checked by scattering and transmittance time difference. Based on the principle of scattering first, transmittance second, and the synchronous state of temperature and humidity in the detection chamber and pressure in the crankcase, water vapor condensation and airflow disturbance are eliminated to obtain the true oil mist particle concentration event set.

[0011] The arrival time of oil mist is determined by the scattering precursor time of the actual oil mist particle concentration event set, and the source of oil mist is inverted by combining the ventilation path adjacency relationship corresponding to the node location identifier, the arrival order of adjacent nodes and the airflow direction corresponding to the crankcase pressure, so as to obtain the oil mist hazard location result.

[0012] Based on the oil mist hazard location results, the continuity of actual oil mist particle concentration events, changes in engine oil temperature, and the overall oil mist concentration state corresponding to the same-direction oil mist response, hierarchical alarm control is performed to obtain the diesel engine oil mist concentration alarm control results.

[0013] As a preferred embodiment of the diesel engine oil mist concentration alarm control method based on multi-sensor fusion described in this invention, wherein obtaining the oil mist concentration detection frame specifically includes:

[0014] The crankcase, main bearing area, connecting rod bearing area, gear transmission area, and oil return chamber are designated as oil mist detection sites, and each oil mist detection site is configured with a corresponding oil mist detection node and node position identifier; the node position identifier includes a detection site identifier and a ventilation path identifier;

[0015] The light scattering signal, light transmittance signal, detection chamber temperature and humidity, crankcase pressure and oil temperature of each oil mist detection node are collected according to a unified sampling clock to obtain the node synchronous sampling group;

[0016] By matching the node synchronous sampling group with the node location identifier according to the sampling time and node order, an oil mist concentration detection frame is obtained.

[0017] As a preferred embodiment of the diesel engine oil mist concentration alarm control method based on multi-sensor fusion described in this invention, the step of converting the light scattering signal and light transmittance signal in the oil mist concentration detection frame into a unidirectional oil mist response quantity specifically includes:

[0018] Select non-alarm stable sampling segments from the oil mist concentration detection frame, and determine the light scattering benchmark and light transmittance benchmark from the non-alarm stable sampling segments to obtain the optical benchmark group;

[0019] The enhancement of the light scattering signal relative to the light scattering reference is determined as the scattering oil mist response quantity, and the scattering oil mist response sequence is obtained;

[0020] The attenuation of the light transmittance reference relative to the light transmittance signal is determined as the transmittance oil mist response, and the transmittance oil mist response sequence is obtained.

[0021] By matching the scattered oil mist response sequence and the transmittance oil mist response sequence according to the sampling time, the same-direction oil mist response quantity with the same response direction when the oil mist concentration increases is obtained.

[0022] As a preferred embodiment of the multi-sensor fusion-based diesel engine oil mist concentration alarm control method of the present invention, wherein obtaining the candidate oil mist mutation event sequence specifically includes:

[0023] The direction of change of scattering response and the direction of change of transmittance response at adjacent sampling times are determined by the same-direction oil mist response, and a dual-channel change direction sequence is obtained;

[0024] Local variation segments of scattering response that first rise and then fall, and first fall and then rise, are extracted from the dual-channel change direction sequence to obtain scattering subtle reversal segments;

[0025] Extract the sampling segment adjacent to the scattering fine reversal segment and whose transmittance response changes in the same direction from the dual-channel change direction sequence to obtain the transmittance same-direction change segment;

[0026] The scattering inversion fragment and the transmittance change fragment are paired according to the sampling time to obtain the initial oil mist mutation fragment;

[0027] The initial oil mist mutation fragments are compared with the crankcase pressure changes and the continuity of the responses of adjacent nodes. The initial oil mist mutation fragments that are not triggered by the instantaneous disturbance of crankcase pressure and that the adjacent oil mist detection nodes show the same direction of oil mist response changes in sequence within a preset transmission time are retained to obtain the candidate oil mist mutation event sequence.

[0028] As a preferred embodiment of the diesel engine oil mist concentration alarm control method based on multi-sensor fusion described in this invention, the step of performing scattering and transmittance time difference verification on the candidate oil mist abrupt event sequence specifically includes:

[0029] The light scattering response segment and light transmittance response segment corresponding to each candidate oil mist mutation event are extracted from the candidate oil mist mutation event sequence to obtain a dual-channel event segment;

[0030] The scattering lead time is obtained by calibrating the sampling time of the first continuous enhancement and the first subtle reversal of the scattering response within the dual-channel event segment;

[0031] The sampling time of the first continuous decay of transmittance response is determined by calibrating the sampling time sequence along the same dual-channel event segment, and the transmittance is obtained after time.

[0032] The oil mist evolution matching result is obtained by comparing the interval between the scattering advance time and the transmittance subsequent time with the preset time range of the oil mist particles from the fine scattering state to the overall shading state.

[0033] The oil mist evolution matching results, the temperature and humidity status of the detection chamber, and the synchronous status of the crankcase pressure are combined and verified. Candidate oil mist mutation events with scattering first, transmittance second, and detection chamber temperature and humidity not meeting condensation conditions and crankcase pressure not being synchronously impacted are retained to obtain the true oil mist particle concentration event set.

[0034] As a preferred embodiment of the multi-sensor fusion-based diesel engine oil mist concentration alarm control method of the present invention, the step of combining and verifying the oil mist evolution matching results, the humidity status of the detection chamber, and the synchronous status of the crankcase pressure specifically includes:

[0035] Candidate oil mist mutation events that are subsequently valid but scattering is missing and the humidity of the detection chamber meets the condensation condition are marked as water vapor condensation interference.

[0036] Candidate oil mist abrupt events that occur simultaneously with crankcase pressure shocks and exhibit a lack of continuity in responses at adjacent nodes are labeled as airflow disturbances.

[0037] To obtain the attributes of real oil mist particle concentration events, we associate the scattering precedence time, transmittance follow-up time, event duration, and corresponding oil mist detection node with each real oil mist particle concentration event in the real oil mist particle concentration event set.

[0038] As a preferred embodiment of the diesel engine oil mist concentration alarm control method based on multi-sensor fusion described in this invention, wherein determining the arrival time of the oil mist specifically includes:

[0039] The scattering precursor time in the actual oil mist particle concentration event attribute is determined as the oil mist arrival time of the corresponding oil mist detection node, thus obtaining the node oil mist arrival time table;

[0040] The node position identifiers are mapped to the ventilation paths between the crankcase, main bearing area, connecting rod bearing area, gear transmission area, and oil return chamber to obtain the adjacency relationship of the ventilation paths;

[0041] The arrival timetable of oil mist at the nodes is sorted according to the adjacency relationship of the ventilation path to obtain the arrival order of adjacent nodes;

[0042] By mapping the direction of crankcase pressure change to the adjacency relationship of the ventilation path, the airflow direction is identified.

[0043] The basic data for oil mist source inversion consists of the arrival order of adjacent nodes and the airflow direction identifier.

[0044] As a preferred embodiment of the diesel engine oil mist concentration alarm control method based on multi-sensor fusion described in this invention, the oil mist source inversion specifically includes:

[0045] The candidate source node group is obtained by selecting the oil mist detection node with the earliest oil mist arrival time and its adjacent detection node upstream along the airflow direction from the basic data of oil mist source inversion.

[0046] The ventilation path sequence from each candidate source node in the candidate source node group to the responding oil mist detection node is determined to obtain the candidate propagation sequence;

[0047] The candidate propagation order is compared with the arrival order of adjacent nodes one by one to obtain the propagation order matching result;

[0048] The propagation sequence matching result is compared with the airflow direction identifier to determine the consistency of the direction, thus obtaining the source node determination result.

[0049] When there are multiple candidate source nodes in the source node determination result, the corresponding relationship between the scattering advance time, transmittance and duration and oil temperature is compared in turn to obtain the target source node.

[0050] The diesel engine part corresponding to the target source node is identified as the abnormal source part, and the ventilation path sequence from the target source node to the oil mist detection node that has responded is determined as the direction of oil mist diffusion, thus obtaining the oil mist hazard location result.

[0051] As a preferred embodiment of the diesel engine oil mist concentration alarm control method based on multi-sensor fusion described in this invention, the step of performing hierarchical alarm control specifically includes:

[0052] Extract the abnormal source location, oil mist diffusion direction, and associated detection nodes from the oil mist hazard location results to obtain alarm location information;

[0053] Based on the actual oil mist particle concentration event set corresponding to the oil mist hazard location results, the number of events occurring at the same abnormal source location and the interval between adjacent events are statistically analyzed to obtain the continuity of actual oil mist particle concentration events.

[0054] The oil temperature change state is determined by the change in oil temperature before and after a real oil mist particle concentration event, thus obtaining the temperature auxiliary state.

[0055] The overall oil mist concentration state is determined based on the same-direction oil mist response, and the concentration auxiliary state is obtained.

[0056] By matching the alarm location information, the continuity of actual oil mist particle concentration events, temperature auxiliary status and concentration auxiliary status, the early warning level, alarm level and shutdown protection level are obtained.

[0057] By correlating the early warning level, alarm level, and shutdown protection level with the location of the abnormal source, the direction of oil mist diffusion, the associated detection nodes, and the alarm time, the alarm control results for diesel engine oil mist concentration are obtained.

[0058] Secondly, this invention provides a diesel engine oil mist concentration alarm control system based on multi-sensor fusion, comprising,

[0059] The synchronous acquisition module synchronously acquires the light scattering signal, light transmittance signal, detection chamber temperature and humidity, crankcase pressure, engine oil temperature and node position identifier of each oil mist detection node, and aligns them according to a unified sampling clock to obtain the oil mist concentration detection frame;

[0060] The event filtering module converts the light scattering signal and light transmittance signal in the oil mist concentration detection frame into the same-direction oil mist response quantity, and combines the crankcase pressure and the continuity of the response of adjacent nodes to filter out subtle scattering reversals and same-direction transmittance changes, thus obtaining candidate oil mist mutation event sequences.

[0061] The time difference verification module performs scattering and transmittance time difference verification on the candidate oil mist mutation event sequence. Based on the principle of scattering first, transmittance second, and the synchronous state of temperature and humidity in the detection chamber and crankcase pressure, water vapor condensation and airflow disturbance are eliminated to obtain the true oil mist particle concentration event set.

[0062] The source inversion module determines the arrival time of oil mist by the scattering precedence time of the real oil mist particle concentration event set, and inverts the source of oil mist by combining the ventilation path adjacency relationship corresponding to the node position identifier, the arrival order of adjacent nodes and the airflow direction corresponding to the crankcase pressure, and obtains the oil mist hazard location result.

[0063] The hierarchical control module performs hierarchical alarm control based on the oil mist hazard location results, the continuity of actual oil mist particle concentration events, changes in engine oil temperature, and the overall oil mist concentration state corresponding to the same-direction oil mist response, thereby obtaining the diesel engine oil mist concentration alarm control results.

[0064] The beneficial effects of this invention are as follows: This invention does not solely rely on whether the oil mist concentration reaches a fixed alarm limit as the judgment criterion. Instead, it utilizes the difference between the sensitivity of light scattering signals to fine oil mist particles and the sensitivity of light transmittance signals to overall shading changes. After converting these two into a co-directional oil mist response quantity, it identifies the true evolution process of oil mist particles from a fine scattering state to an overall shading state through time difference verification of scattering first and transmittance second. This distinguishes it from the single-channel concentration alarm or simple multi-sensor superposition judgment method in existing technologies. At the same time, the temperature and humidity status of the detection chamber and the synchronous status of crankcase pressure are included in the verification process, which can effectively eliminate false oil mist anomalies caused by water vapor condensation and airflow pulsation, reducing the probability of false alarms. By using the scattering-first moment in the real oil mist particle concentration event to determine the oil mist arrival time, and combining the adjacency relationship of the ventilation path, the arrival order of adjacent nodes, and the airflow direction to invert the abnormal source location, the alarm result is upgraded from a concentration exceeding the limit prompt to a comprehensive detection result that confirms the real oil mist event, locates the abnormal source, and judges the diffusion direction. This improves the early identification capability, interference elimination capability, and fault location reliability of diesel engine oil mist alarms. Attached Figure Description

[0065] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. 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.

[0066] Figure 1 This is a flowchart of a diesel engine oil mist concentration alarm control method based on multi-sensor fusion.

[0067] Figure 2 A flowchart for generating oil mist concentration detection frames and constructing co-directional responses is provided.

[0068] Figure 3 Flowchart for candidate event screening and scattering and transmittance time difference verification.

[0069] Figure 4 This is a flowchart for oil mist source inversion and hierarchical alarm control.

[0070] Figure 5 This is a schematic diagram of the internal ventilation path topology of a diesel engine.

[0071] Figure 6 This is a schematic diagram of a dual-channel grayscale event band. Detailed Implementation

[0072] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0073] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0074] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0075] Reference Figures 1-6 This is one embodiment of the present invention, which provides a diesel engine oil mist concentration alarm control method based on multi-sensor fusion, comprising the following steps:

[0076] S1. Synchronously collect the light scattering signal, light transmittance signal, detection chamber temperature and humidity, crankcase pressure, engine oil temperature and node position identifier of each oil mist detection node, and align them according to a unified sampling clock to obtain the oil mist concentration detection frame.

[0077] S1.1. Register the crankcase, main bearing area, connecting rod bearing area, gear transmission area and oil return chamber as oil mist detection locations, and configure corresponding oil mist detection nodes in each oil mist detection location to obtain an oil mist detection node group.

[0078] Each oil mist detection node in the oil mist detection node group is configured with a node location identifier. The node location identifier consists of a detection location identifier and a ventilation path identifier. The detection location identifier indicates the crankcase, main bearing area, connecting rod bearing area, gear transmission area, and oil return chamber corresponding to the oil mist detection node. The ventilation path identifier indicates the order of oil mist ventilation between adjacent oil mist detection nodes, thus obtaining the node location identifier table.

[0079] Synchronously write to the node location identifier table Figure 5 The diagram shows the topological labeling of the internal ventilation paths of the diesel engine. The oil mist detection node corresponding to the crankcase is denoted as N1, the oil mist detection node corresponding to the main bearing area as N2, the oil mist detection node corresponding to the connecting rod bearing area as N3, the oil mist detection node corresponding to the gear transmission area as N4, and the oil mist detection node corresponding to the oil return chamber as N5. The direct ventilation paths between adjacent detection points are denoted as P1, P2, P3, P4, and P5, respectively. P1 corresponds to the ventilation path between the crankcase and the main bearing area, P2 corresponds to the ventilation path between the main bearing area and the connecting rod bearing area, P3 corresponds to the ventilation path between the crankcase and the gear transmission area, P4 corresponds to the ventilation path between the crankcase and the oil return chamber, and P5 corresponds to the ventilation path between the gear transmission area and the oil return chamber. Figure 5The circular detection symbol in the diagram represents an oil mist detection node, and the double-headed arrow indicates that there is a ventilation path between adjacent detection points that can be used to determine the propagation of oil mist. The actual airflow direction of the ventilation path is determined by the crankcase pressure change at the corresponding sampling time.

[0080] The node location identifier table is associated with a unified sampling clock, and a sampling time sequence is generated according to the start time and sampling period of the unified sampling clock. The sampling time sequence is derived from the fixed-period clock calibration relationship in the field of digital sampling. Each sampling time is obtained by accumulating the sampling period from the start time, and the expression is:

[0081] ;

[0082] in, For the first Each sampling time; To standardize the start time of the sampling clock; The sampling sequence number; To standardize the sampling period of the sampling clock, it is used to define the time interval between adjacent sampling moments.

[0083] S1.2. At each sampling time in the sampling time sequence, the light scattering signal, light transmittance signal, detection cavity temperature and humidity, crankcase pressure, and engine oil temperature of each oil mist detection node in the oil mist detection node group are collected to obtain the original sampling record of the node; among them, the light scattering signal represents the scattering enhancement caused by fine oil mist particles, the light transmittance signal represents the overall light-blocking change of oil mist, the detection cavity temperature and humidity are used to determine the influence of water vapor condensation on optical detection, the crankcase pressure is used to determine the disturbance of airflow pulsation on the oil mist channel, and the engine oil temperature is used to assist in determining the source of lubricating oil atomization.

[0084] Align the actual sampling time in the node's original sampling record with the sampling time sequence, assigning the actual sampling time to the nearest sampling time; the conditional expression for the node's original sampling record entering the same sampling time is:

[0085] ;

[0086] in, For the first The first oil mist detection node The actual sampling time of the signal; Number the oil mist detection nodes; The signal categories are numbered, including light scattering signals, light transmittance signals, detection chamber temperature and humidity, crankcase pressure, and engine oil temperature. For the first Each sampling time; To standardize the sampling period of the sampling clock, it is used to define the range of subjects for the same sampling moment.

[0087] The original sampling records of nodes that satisfy the above expression are entered into the node synchronization sampling group; when there are duplicate sampling records of the same oil mist detection node at the same sampling time, the original sampling record of the node with the smallest difference between the actual sampling time and the sampling time sequence is retained; when any signal category does not satisfy the above expression at the same sampling time, the same oil mist detection node does not form a node synchronization sampling group at the same sampling time.

[0088] The node synchronous sampling group and the node position identification table are matched according to the sampling time and node order, so that each oil mist detection node has light scattering signal, light transmittance signal, detection cavity temperature and humidity, crankcase pressure, oil temperature, detection part identification and ventilation path identification at the same sampling time, thus obtaining the oil mist concentration detection frame.

[0089] S2. Convert the light scattering signal and light transmittance signal in the oil mist concentration detection frame into the same-direction oil mist response quantity, and combine the crankcase pressure and the continuity of the response of adjacent nodes to screen for subtle scattering reversals and same-direction transmittance changes to obtain candidate oil mist mutation event sequences.

[0090] S2.1. Select a non-alarm stable sampling segment from the continuous sampling time of the oil mist concentration detection frame. The non-alarm stable sampling segment is the sampling segment in which no graded alarm control record is generated and the light scattering signal and light transmittance signal maintain stable fluctuation within the repeatability range of the sensor at the factory. Perform arithmetic averaging on the light scattering signal and light transmittance signal of the same oil mist detection node in the non-alarm stable sampling segment to obtain the light scattering reference and light transmittance reference, and form an optical reference group with the light scattering reference and light transmittance reference.

[0091] The reference value for the optical detection signal is determined by calculation using the average value, expressed as:

[0092] ;

[0093] ;

[0094] in, For the first The light scattering reference of each oil mist detection node is used to represent the stable reference value of the light scattering signal within the non-alarm stable sampling section; For the first The light transmittance benchmark of each oil mist detection node is used to represent the stable reference value of the light transmittance signal within the non-alarm stable sampling segment; This represents the number of sampling points within the non-alarm stable sampling segment. For the first The oil mist detection node is in the non-alarm stable sampling segment. The light scattering signal at each sampling point; For the first The oil mist detection node is in the non-alarm stable sampling segment. The light transmittance signal at each sampling point.

[0095] S2.2. The first frame in the oil mist concentration detection frame The oil mist detection node at the first The difference between the light scattering signal at each sampling time and the light scattering reference is calculated to obtain the scattered oil mist response; the difference between the light transmittance reference and the light transmittance signal of the same oil mist detection node at the same sampling time is calculated to obtain the transmittance oil mist response.

[0096] The difference calculation originates from the optical sensor's method of detecting the change in relative to a reference. In this embodiment, the opposite physical response directions of light scattering enhancement and light transmittance attenuation are utilized to convert the two types of optical detection signals into values ​​with the same response direction when the oil mist concentration increases. The expression is as follows:

[0097] ;

[0098] ;

[0099] in, For the first The oil mist detection node at the first The scattered oil mist response at each sampling time is used to represent the scattering enhancement caused by fine oil mist particles; For the first The oil mist detection node at the first The transmittance oil mist response at each sampling time is used to represent the transmittance attenuation caused by the overall shading effect of the oil mist. For the first The oil mist detection node at the first The light scattering signal at each sampling time; For the first The oil mist detection node at the first The light transmittance signal at each sampling time.

[0100] The scattered oil mist response quantities at consecutive sampling times are arranged into a scattered oil mist response sequence, and the transmittance oil mist response quantities at consecutive sampling times are arranged into a transmittance oil mist response sequence. According to the sampling time and oil mist detection node number in the oil mist concentration detection frame, the scattered oil mist response sequence and the transmittance oil mist response sequence are matched to obtain the same-direction oil mist response quantity. The same-direction oil mist response quantity includes the scattered oil mist response quantity and the transmittance oil mist response quantity of the same oil mist detection node at the same sampling time.

[0101] S2.3. Calculate the changes in scattering response and transmittance response at adjacent sampling times using the same-direction oil mist response, and determine the directions of change in scattering response and transmittance response respectively to obtain a dual-channel change direction sequence; before determining the directions of change in scattering response and transmittance response, extract the changes in scattering response and transmittance response of the same oil mist detection node from the non-alarm stable sampling segment. The non-alarm stable sampling segment is a continuous sampling segment in which no graded alarm control record is generated, the temperature and humidity of the detection chamber do not meet the condensation conditions, the crankcase pressure does not experience instantaneous impact, and the same-direction oil mist response remains stable; the number of continuous sampling points in the non-alarm stable sampling segment is not less than 100, and the average change and standard deviation of the changes in scattering response and transmittance response are calculated respectively, and the interval defined by three times the standard deviation above and below the average change is taken as the normal fluctuation range of the corresponding channel.

[0102] For example, when the average change in the scattering response is 0 digits and the standard deviation is 3 digits, the normal fluctuation range of the scattering response change is from -9 digits to 9 digits; when the average change in the transmittance response change is 0 digits and the standard deviation is 4 digits, the normal fluctuation range of the transmittance response change is from -12 digits to 12 digits.

[0103] When the change in scattering response is greater than the upper limit of the normal fluctuation range of scattering response, the direction of scattering response change is upward; when the change in scattering response is less than the lower limit of the normal fluctuation range of scattering response, the direction of scattering response change is downward; when the change in scattering response is within the normal fluctuation range of scattering response, the direction of scattering response change is stable; the direction of transmittance response change is determined by the change in transmittance response according to the same rule; thus, the dual-channel change direction sequence of each oil mist detection node at continuous sampling time is obtained.

[0104] From the dual-channel change direction sequence, local change segments in the scattering response direction of the same oil mist detection node within continuous sampling time, where the scattering response changes from rising to falling and from falling to rising, are obtained to obtain scattering fine reversal segments. Scattering fine reversal segments represent local fluctuations caused by fine oil mist particles in the light scattering channel, rather than simply representing a decrease in overall oil mist concentration. In adjacent sampling intervals of scattering fine reversal segments, the transmittance response change direction is searched. When the transmittance response change direction continuously points to the direction of increasing oil mist concentration, transmittance co-directional change segments are obtained.

[0105] S2.4. Pair the scattering inversion fragment with the transmittance change fragment according to the sampling time. The pairing result retains the oil mist detection node number, the time when the scattering inversion occurs, the time when the transmittance change begins, and the corresponding node position identifier to obtain the initial oil mist mutation fragment. The initial oil mist mutation fragment is used to indicate the optical change process in which the scattering response has shown particulate fluctuations and the transmittance response has shown an overall shading trend.

[0106] The initial oil mist mutation segment is compared with the crankcase pressure change at the same sampling time. When the initial oil mist mutation segment only occurs simultaneously with the instantaneous change in crankcase pressure, and the same-direction change segment of transmittance is not continuous, and the adjacent oil mist detection nodes do not show the same-direction oil mist response change in sequence within the transmission time range, the initial oil mist mutation segment is excluded as a crankcase pressure disturbance segment. The transmission time range is determined by the calibration transmission delay between adjacent oil mist detection nodes and the unified sampling clock. The calibration transmission delay is the time difference between the first occurrence of the same-direction oil mist response quantity continuous change at the upstream oil mist detection node and the first occurrence of the same-direction oil mist response quantity continuous change at the downstream adjacent oil mist detection node. The transmission time range is the time interval formed by one sampling cycle before and after the calibration transmission delay.

[0107] In this embodiment, the sampling period of the unified sampling clock is 100 milliseconds, and when the calibration transmission delay of adjacent oil mist detection nodes is 300 to 500 milliseconds, the corresponding transmission time range is 200 to 600 milliseconds.

[0108] Initial oil mist mutation fragments that are not triggered solely by instantaneous crankcase pressure disturbances and where adjacent oil mist detection nodes sequentially exhibit unidirectional oil mist response changes within the transmission time range are retained to obtain candidate oil mist mutation events. The candidate oil mist mutation events are arranged according to their occurrence time, oil mist detection node number, and node position identifier to obtain a candidate oil mist mutation event sequence.

[0109] S3. Perform scattering and transmittance time difference verification on the candidate oil mist mutation event sequence. Based on the principle of scattering first, transmittance second, and synchronous state of temperature and humidity in the detection chamber and crankcase pressure, eliminate water vapor condensation and airflow disturbance to obtain the true oil mist particle concentration event set.

[0110] S3.1. Extract candidate oil mist mutation events one by one from the candidate oil mist mutation event sequence, and take the time of the occurrence of the scattering subtle inversion of the candidate oil mist mutation event as the center, and extract the scattering oil mist response sequence and transmittance oil mist response sequence of the same oil mist detection node before and after the occurrence time to obtain light scattering response segment and light transmittance response segment; arrange the light scattering response segment and light transmittance response segment according to the corresponding sampling time to obtain dual-channel event segment; the light scattering response segment in the dual-channel event segment is used to present the scattering enhancement and subtle inversion caused by fine oil mist particles, and the light transmittance response segment is used to present the continuous attenuation caused by the overall shading of oil mist.

[0111] The dual-channel event segments are arranged into dual-channel grayscale event bands according to the sampling time, such as... Figure 6 As shown, the dual-channel grayscale event band includes an upper light scattering response segment and a lower light transmittance response segment. The lateral sampling time is consistent with the unified sampling clock, and the grayscale depth corresponds to the intensity of the change in the amount of oil mist response relative to the optical reference group in the same direction; wherein, Figure 6 The "first continuous enhancement sampling segment" and "first subtle inversion sampling point" in the image correspond to the granular response boundary of the light scattering response segment, while the "first continuous decay sampling segment" corresponds to the overall shading response boundary of the light transmittance response segment. The grayscale indicator on the right is used to represent the enhanced dual-channel event segment. Image enhancement processing is performed on the dual-channel grayscale event band to ensure that the continuous enhancement boundary, subtle inversion boundary, and continuous decay boundary in the light scattering response segment remain distinguishable in terms of grayscale changes. The image enhancement processing is only used to enhance the response boundaries in the dual-channel event segment and does not change the sampling time and response amount corresponding to the dual-channel event segment. The enhanced dual-channel grayscale event band still corresponds to the light scattering response segment and light transmittance response segment in the original dual-channel event segment, resulting in the enhanced dual-channel event segment.

[0112] S3.2. Within the enhanced dual-channel event segment, locate the first continuous enhanced sampling segment of the light scattering response segment along the sampling time sequence, and locate the first subtle reversal sampling point near the first continuous enhanced sampling segment where the direction of scattering response changes from rising to falling and from falling to rising; mark the earliest sampling time between the starting sampling time of the first continuous enhanced sampling segment and the sampling time of the first subtle reversal sampling point as the scattering leading time, thus obtaining the enhanced dual-channel event segment with the scattering leading time.

[0113] Reference Figure 6 The scattering lead time is marked by a vertical dashed line passing through the light scattering response segment, which is used to distinguish the moment when fine oil mist particles first cause a change in the scattering response from the subsequent change in transmittance.

[0114] The first continuously attenuated sampling segment of the light transmittance response segment is found along the enhanced dual-channel event segment with the scattering precedence time. The first continuously attenuated sampling segment is the light transmittance response segment that shows an attenuation change in the direction of increasing oil mist concentration throughout the continuous sampling time, and the continuous attenuation change is not covered by the normal fluctuation range of the non-alarm stable sampling segment. The starting sampling time of the first continuously attenuated sampling segment is marked as the transmittance follow-up time, thus obtaining the enhanced dual-channel event segment with the scattering precedence time and the transmittance follow-up time.

[0115] Reference Figure 6 The transmittance is marked by another vertical dashed line passing through the transmittance response segment at the next time step. The bidirectional arrow between the scattering-preceding time step and the transmittance-preceding time step corresponds to the time difference between scattering and transmittance, so that the dual-channel grayscale event band can directly reflect the oil mist evolution process where the fine scattering state appears first and the overall shading state appears later.

[0116] The time difference between scattering and transmittance is calculated based on the scattering lead time and transmittance follow time. This time difference is calculated by the difference between the times of two events occurring on the same time axis, with the scattering lead time taken as the starting time of the scattering state of fine oil mist particles. The scattering and transmittance time difference is compared with the calibration time range for the oil mist particles to transition from a fine scattering state to a state of overall light blocking. This calibration time range is obtained through bench calibration. During bench calibration, standard oil mist is released at the corresponding oil mist detection location at the oil mist detection node, and the sampling times of the first continuous enhancement of the light scattering response and the first continuous decay of the light transmittance response are recorded. The time difference between these two times is taken as the time difference between a single scattering and transmittance event.

[0117] After removing calibration records where the temperature and humidity of the detection chamber met the condensation conditions and the crankcase pressure experienced synchronous impact, the sampling period of the remaining scattering and transmittance time difference was aligned to obtain the calibration time range in which the oil mist particles changed from a fine scattering state to an overall light-blocking state.

[0118] In this embodiment, the sampling period of the unified sampling clock is 100 milliseconds. The effective scattering and transmittance time difference obtained by bench calibration is concentrated between 180 milliseconds and 720 milliseconds. After rounding outwards according to the unified sampling clock, the calibration time range is 100 milliseconds to 800 milliseconds. When the scattering and transmittance time difference is within 100 milliseconds to 800 milliseconds, the oil mist evolution matching result is valid. When the scattering and transmittance time difference is less than 100 milliseconds, exceeds 800 milliseconds, or the transmittance time precedes the scattering time, the oil mist evolution matching result is invalid.

[0119] S3.3. Compare the oil mist evolution matching results with the detection chamber temperature and humidity status at the same sampling time of the candidate oil mist mutation event; the detection chamber temperature and humidity status is jointly determined by the detection chamber temperature and humidity. When the detection chamber temperature is close to the water vapor condensation temperature and the detection chamber humidity is in a high humidity state, the detection chamber temperature and humidity meet the condensation condition; when the transmittance is subsequently established but the scattering is first missing, and the detection chamber temperature and humidity meet the condensation condition, the candidate oil mist mutation event is marked as water vapor condensation interference, and the candidate oil mist mutation event with water vapor condensation interference label is obtained.

[0120] The oil mist evolution matching results are compared with the crankcase pressure synchronization state corresponding to the same sampling time of the candidate oil mist mutation event. The crankcase pressure synchronization state indicates whether the crankcase pressure impact time, the scattering precedence time, and the transmittance follow-up time fall within the same sampling time range. When the scattering precedence and the transmittance follow-up appear synchronously with the crankcase pressure impact and the continuity of the response of adjacent nodes is missing, the candidate oil mist mutation event is marked as an airflow disturbance, and the candidate oil mist mutation event with the airflow disturbance mark is obtained.

[0121] Candidate oil mist mutation events that are valid in oil mist evolution matching, do not meet the condensation conditions in the detection chamber temperature and humidity, do not have synchronous impact in the crankcase pressure, and do not have water vapor condensation interference markers and airflow disturbance markers are retained to obtain real oil mist particle concentration events. The real oil mist particle concentration events are arranged according to the occurrence time, corresponding oil mist detection node, and node position identifier to obtain the real oil mist particle concentration event set.

[0122] For each real oil mist particle concentration event in the real oil mist particle concentration event set, associate the scattering-preceding time, transmittance-following time, event duration, and corresponding oil mist detection node; the event duration is determined by the difference between the end time of the real oil mist particle concentration event and the scattering-preceding time. By mapping the scattering-preceding time, transmittance-following time, event duration, and corresponding oil mist detection node to the real oil mist particle concentration event set, the attributes of the real oil mist particle concentration events are obtained.

[0123] S4. Determine the arrival time of oil mist by the scattering precedence time of the actual oil mist particle concentration event set, and invert the source of oil mist by combining the adjacency relationship of the ventilation path corresponding to the node location identifier, the arrival order of adjacent nodes and the airflow direction corresponding to the crankcase pressure, and obtain the oil mist hazard location result.

[0124] S4.1. Extract the corresponding oil mist detection node, scattering advance time, transmittance follow-up time, event duration, and node location identifier from the actual oil mist particle concentration event attributes; determine the scattering advance time in the actual oil mist particle concentration event attributes as the oil mist arrival time of the corresponding oil mist detection node to obtain the node oil mist arrival time table; the node oil mist arrival time table includes the oil mist detection node number, detection location identifier, ventilation path identifier, oil mist arrival time, transmittance follow-up time, and event duration.

[0125] In the oil mist arrival time table, the oil mist detection node number and... Figure 5 The topological nodes in the diagram correspond one-to-one: the oil mist detection node corresponding to the crankcase is denoted as N1, the oil mist detection node corresponding to the main bearing area is denoted as N2, the oil mist detection node corresponding to the connecting rod bearing area is denoted as N3, the oil mist detection node corresponding to the gear transmission area is denoted as N4, and the oil mist detection node corresponding to the oil return chamber is denoted as N5. The direct ventilation paths between adjacent detection points are denoted as P1, P2, P3, P4, and P5, respectively, to ensure that the oil mist arrival time at each node can be along... Figure 5 The internal ventilation path topology of the diesel engine is sorted, rather than simply by the installation number of the detection node.

[0126] Based on the ventilation path identifiers in the node location identifiers, the sequential relationship of oil mist ventilation between the crankcase, main bearing area, connecting rod bearing area, gear transmission area, and oil return chamber is organized into a ventilation path adjacency relationship. The ventilation path adjacency relationship indicates whether there is a direct ventilation relationship between any two adjacent oil mist detection nodes, as well as the upstream oil mist detection node and the downstream adjacent oil mist detection node corresponding to the direct ventilation relationship.

[0127] Reference Figure 5 P1, P2, P3, P4 and P5 are respectively the edges in the ventilation path adjacency relationship, and N1, N2, N3, N4 and N5 are respectively the nodes in the ventilation path adjacency relationship. The bidirectional arrows in the figure indicate that the corresponding edges are structurally allowed to connect the oil mist along the adjacent detection parts, but the specific propagation direction needs to be determined by the subsequent crankcase pressure change direction.

[0128] Arrange the oil mist arrival timetable of the nodes according to the adjacency relationship of the ventilation path to obtain the arrival order of adjacent nodes; the arrival order of adjacent nodes represents the time sequence of the actual oil mist particle concentration event along the ventilation path between adjacent oil mist detection nodes.

[0129] Among them, direct ventilation relationship means that there is a continuous crankcase internal space, bearing cavity connecting hole, gear transmission cavity connecting channel, oil return cavity connecting channel or crankcase ventilation channel between the oil mist detection parts corresponding to two adjacent oil mist detection nodes, and the oil mist does not pass through the oil mist detection part corresponding to the third configured oil mist detection node when flowing from one oil mist detection part to another.

[0130] S4.2. Based on the crankcase pressure change direction at the corresponding sampling time of adjacent oil mist detection nodes in the oil mist concentration detection frame, determine the airflow direction identifier corresponding to the crankcase pressure; when there is a crankcase pressure change from high to low at the detection locations corresponding to adjacent oil mist detection nodes, determine the ventilation path direction from the high-pressure detection location to the low-pressure detection location as the airflow direction identifier; when there is no stable crankcase pressure change from high to low at the same sampling time for the detection locations corresponding to adjacent oil mist detection nodes, record the airflow direction identifier of the corresponding ventilation path as uncertain; refer to Figure 5 In the diagram, the circular detection symbols represent oil mist detection nodes, and the double-headed arrows indicate ventilation paths between adjacent detection points that can be used to determine oil mist propagation. The actual airflow direction of the ventilation path is determined by the crankcase pressure change at the corresponding sampling time. Figure 5 The reversible ventilation path can be converted into a single airflow direction identifier for source inversion at each sampling time based on the pressure relationship. The arrival order of adjacent nodes and the airflow direction identifier are combined to obtain the basic data for oil mist source inversion.

[0131] The oil mist detection node with the earliest oil mist arrival time is selected from the basic data of oil mist source inversion. Then, the upstream adjacent detection nodes of the oil mist detection node with the earliest oil mist arrival time are found along the airflow direction marker to obtain the candidate source node group. The candidate source node group includes the oil mist detection node with the earliest oil mist arrival time, as well as the adjacent oil mist detection nodes that have a direct airflow relationship with the oil mist detection node with the earliest oil mist arrival time and are located upstream in the airflow direction. Oil mist detection nodes that have already appeared in the node oil mist arrival time table are identified as responding oil mist detection nodes.

[0132] S4.3. For each candidate source node in the candidate source node group, arrange the candidate source nodes and the oil mist detection nodes passed between them and each responded oil mist detection node in order of the adjacency relationship of the ventilation path to obtain the candidate propagation order; compare the candidate propagation order with the arrival order of adjacent nodes one by one. If the oil mist detection node closer to the candidate source node in the candidate propagation order has an oil mist arrival time earlier than the oil mist detection node farther away from the candidate source node, then the propagation order matching result of the corresponding candidate source node is valid; if the candidate propagation order is inconsistent with the arrival order of adjacent nodes, then the propagation order matching result of the corresponding candidate source node is invalid; break down the candidate propagation order with valid propagation order matching result into the segmented propagation direction between adjacent oil mist detection nodes, and compare the segmented propagation direction with the airflow direction label. When each segmented propagation direction is consistent with the airflow direction label, or the airflow direction label is uncertain but the arrival order of adjacent nodes still conforms to the propagation relationship from near to far, the direction consistency judgment is valid; when any segmented propagation direction is opposite to the airflow direction label, the direction consistency judgment is invalid; combine the propagation order matching result and the direction consistency judgment result to obtain the source node judgment result.

[0133] S4.4. When the source node determination result contains only one candidate source node with a valid propagation order matching result, the candidate source node with the valid propagation order matching result is determined as the target source node; when the source node determination result contains multiple candidate source nodes with valid propagation order matching results, the corresponding relationships of scattering precedence time, transmittance followed by duration, and oil temperature change in the actual oil mist particle concentration event attributes of each candidate source node are compared in turn, and the candidate source node with the earliest scattering precedence time, the longest transmittance followed by duration, and the oil temperature change relationship closest to the corresponding detection location is determined as the target source node; when the source node determination result does not contain any candidate source nodes with valid propagation order matching results, the oil mist detection node with the earliest oil mist arrival time is determined as the target source node.

[0134] The detection site corresponding to the target source node is identified as the abnormal source site, and the ventilation path sequence from the target source node to the responding oil mist detection node is identified as the oil mist diffusion direction. The abnormal source site, the time of the first oil mist particle concentration event, the oil mist diffusion direction, the target source node, the responding oil mist detection node and the corresponding node location identifier are matched to obtain the oil mist hazard location result.

[0135] S5. Based on the oil mist hazard location results, the continuity of actual oil mist particle concentration events, changes in engine oil temperature, and the overall oil mist concentration state corresponding to the same-direction oil mist response, perform graded alarm control to obtain the diesel engine oil mist concentration alarm control results.

[0136] S5.1. Extract the abnormal source location, oil mist diffusion direction, target source node, responded oil mist detection node, and corresponding node location identifier from the oil mist hazard location results. Then, match the scattering precedence time and transmittance follow-up time of the actual oil mist particle concentration event set with the target source node and responded oil mist detection node to obtain alarm location information. The alarm location information includes the abnormal source location, oil mist diffusion direction, associated detection node, the time of the first oil mist particle concentration event, and the corresponding node location identifier.

[0137] Based on the actual oil mist particle concentration event set corresponding to the oil mist hazard location results, the number of actual oil mist particle concentration events occurring at the same abnormal source location within consecutive sampling times is counted, and the time interval between adjacent actual oil mist particle concentration events is calculated according to the scattering precedence time. When the number of actual oil mist particle concentration events occurring at the same abnormal source location is not less than 2, and the time interval between adjacent actual oil mist particle concentration events does not exceed the transmission time range of the corresponding ventilation path, the actual oil mist particle concentration events at the same abnormal source location are judged as continuous occurrences, thus obtaining the continuity of actual oil mist particle concentration events. When the number of actual oil mist particle concentration events occurring at the same abnormal source location is 1, or the time interval between adjacent actual oil mist particle concentration events exceeds the transmission time range of the corresponding ventilation path, the actual oil mist particle concentration events at the same abnormal source location are judged as discontinuous occurrences, thus obtaining the continuity of actual oil mist particle concentration events.

[0138] S5.2. Extract the engine oil temperature before and after the occurrence of the actual oil mist particle concentration event from the oil mist concentration detection frame, and determine the normal fluctuation range of engine oil temperature based on the range of engine oil temperature change within the non-alarm stable sampling segment; when the engine oil temperature after the occurrence of the actual oil mist particle concentration event is higher than the engine oil temperature before the occurrence of the actual oil mist particle concentration event, and the amount of engine oil temperature change exceeds the upper limit of the normal fluctuation range of engine oil temperature, the engine oil temperature rise state is obtained; when the amount of engine oil temperature change before and after the occurrence of the actual oil mist particle concentration event is within the normal fluctuation range of engine oil temperature, the engine oil temperature stable state is obtained; the engine oil temperature rise state and the engine oil temperature stable state constitute the temperature auxiliary state.

[0139] The scattered oil mist response and transmittance oil mist response of the abnormal source location and associated detection node at the same sampling time are extracted from the same direction oil mist response, and the scattered oil mist response and transmittance oil mist response are compared with the alarm limit and shutdown alarm limit adopted by the graded alarm control.

[0140] The alarm limit is obtained by standard oil mist calibration. During calibration, standard oil mist with a concentration of 2.5 mg / L is introduced into the oil mist detection node, and the scattered oil mist response and the transmittance oil mist response after conversion of the light scattering signal and the light transmittance signal are recorded. The recorded results are used as the alarm limit of the corresponding oil mist detection node. The shutdown alarm limit is obtained by standard oil mist calibration. During calibration, standard oil mist with a concentration of 5.0 mg / L is introduced into the oil mist detection node, and the scattered oil mist response and the transmittance oil mist response after conversion of the light scattering signal and the light transmittance signal are recorded. The recorded results are used as the shutdown alarm limit of the corresponding oil mist detection node. Among them, 2.5 mg / L corresponds to 5% of the lower explosive limit of oil mist and is used for oil mist alarm, and 5.0 mg / L corresponds to 10% of the lower explosive limit of oil mist and is used for shutdown protection judgment.

[0141] When neither the scattered oil mist response nor the transmitted oil mist response reaches the alarm limit, the overall oil mist concentration state is obtained as follows: when at least one of the scattered oil mist response and the transmitted oil mist response reaches the alarm limit but does not reach the shutdown alarm limit, the overall oil mist concentration state is obtained as follows: when at least one of the scattered oil mist response and the transmitted oil mist response reaches the shutdown alarm limit, the overall oil mist concentration state is obtained as follows: when neither the scattered oil mist response nor the transmitted oil mist response reaches the shutdown alarm limit, the overall oil mist concentration state is obtained as follows: when neither the alarm limit nor the alarm limit is reached, when the alarm limit is reached, and when the shutdown alarm limit is reached, the overall oil mist concentration state is obtained as follows: when neither the alarm limit nor the alarm limit is reached, the alarm limit is reached, and when the shutdown alarm limit is reached, the overall oil mist concentration state is obtained as follows: when neither the alarm limit nor the alarm limit is reached, the alarm limit is reached, and the shutdown alarm limit is reached, the overall oil mist concentration state is obtained as follows: when neither the alarm limit nor the alarm limit is reached, the overall oil mist concentration state is obtained as follows: when neither the scattered oil mist response nor the transmitted oil mist response reaches the shutdown alarm limit ...

[0142] S5.3. Match the alarm location information, the continuity of actual oil mist particle concentration events, the temperature auxiliary status, and the concentration auxiliary status to the appropriate levels. When the alarm location information has an abnormal source location and the concentration auxiliary status is below the alarm limit, an early warning level is obtained. When the actual oil mist particle concentration events are continuous and the concentration auxiliary status reaches the alarm limit, an alarm level is obtained. When the concentration auxiliary status reaches the shutdown alarm limit, a shutdown protection level is obtained. When the actual oil mist particle concentration events are continuous, the temperature auxiliary status is oil temperature rising, and the associated detection node continuously shows the same direction oil mist response along the oil mist diffusion direction, a shutdown protection level is obtained.

[0143] The early warning level, alarm level, and shutdown protection level are correlated with the location of the abnormal source, the direction of oil mist diffusion, the associated detection node, the time of the first oil mist particle concentration event, and the alarm time. Among them, the alarm time is the sampling time corresponding to the formation of the early warning level, alarm level, or shutdown protection level. The corresponding early warning level, alarm level, shutdown protection level, location of the abnormal source, direction of oil mist diffusion, associated detection node, time of the first oil mist particle concentration event, and alarm time are compiled into the diesel engine oil mist concentration alarm control result.

[0144] This embodiment also provides a diesel engine oil mist concentration alarm control system based on multi-sensor fusion, including:

[0145] The synchronous acquisition module synchronously acquires the light scattering signal, light transmittance signal, detection chamber temperature and humidity, crankcase pressure, engine oil temperature and node position identifier of each oil mist detection node, and aligns them according to a unified sampling clock to obtain the oil mist concentration detection frame;

[0146] The event filtering module converts the light scattering signal and light transmittance signal in the oil mist concentration detection frame into the same-direction oil mist response quantity, and combines the crankcase pressure and the continuity of the response of adjacent nodes to filter out subtle scattering reversals and same-direction transmittance changes, thus obtaining candidate oil mist mutation event sequences.

[0147] The time difference verification module performs scattering and transmittance time difference verification on the candidate oil mist mutation event sequence. Based on the principle of scattering first, transmittance second, and the synchronous state of temperature and humidity in the detection chamber and crankcase pressure, water vapor condensation and airflow disturbance are eliminated to obtain the true oil mist particle concentration event set.

[0148] The source inversion module determines the arrival time of oil mist by the scattering precedence time of the real oil mist particle concentration event set, and inverts the source of oil mist by combining the ventilation path adjacency relationship corresponding to the node position identifier, the arrival order of adjacent nodes and the airflow direction corresponding to the crankcase pressure, and obtains the oil mist hazard location result.

[0149] The hierarchical control module performs hierarchical alarm control based on the oil mist hazard location results, the continuity of actual oil mist particle concentration events, changes in engine oil temperature, and the overall oil mist concentration state corresponding to the same-direction oil mist response, thereby obtaining the diesel engine oil mist concentration alarm control results.

[0150] In summary, this invention does not solely rely on whether the oil mist concentration reaches a fixed alarm limit as the criterion. Instead, it utilizes the difference between light scattering signals' sensitivity to fine oil mist particles and light transmittance signals' sensitivity to overall shading changes. After converting these two into a co-directional oil mist response quantity, it identifies the true evolution process of oil mist particles from a fine scattering state to an overall shading state through time difference verification of scattering first and transmittance second. This distinguishes it from existing technologies that use single-channel concentration alarms or simple multi-sensor superposition judgments. Simultaneously, by incorporating the temperature and humidity status of the detection chamber and the synchronous status of the crankcase pressure into the verification process, it can effectively eliminate false oil mist anomalies caused by water vapor condensation and airflow pulsation, reducing the probability of false alarms. By using the scattering-first moment in a real oil mist particle concentration event to determine the oil mist arrival time, and combining the adjacency relationship of the ventilation path, the arrival order of adjacent nodes, and the airflow direction to invert the abnormal source location, the alarm result is upgraded from a concentration exceeding the limit indication to a comprehensive detection result that confirms a real oil mist event, locates the abnormal source, and determines the diffusion direction. This improves the early identification capability, interference elimination capability, and fault location reliability of diesel engine oil mist alarms.

[0151] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A diesel engine oil mist concentration alarm control method based on multi-sensor fusion, characterized in that: include, Simultaneously collect light scattering signals, light transmittance signals, detection chamber temperature and humidity, crankcase pressure, engine oil temperature, and node position markers at each oil mist detection node, and align them according to a unified sampling clock to obtain an oil mist concentration detection frame; The light scattering signal and light transmittance signal in the oil mist concentration detection frame are converted into unidirectional oil mist response quantities. Combined with crankcase pressure and the continuity of response of adjacent nodes, the subtle reversal of scattering and unidirectional changes in transmittance are screened to obtain a candidate oil mist mutation event sequence. The unidirectional oil mist response quantities include the scattering oil mist response quantity and transmittance oil mist response quantity corresponding to the same oil mist detection node at the same sampling time, and the two respond in the same direction when the oil mist concentration increases. The candidate oil mist mutation event sequence is checked by scattering and transmittance time difference. Based on the principle of scattering first, transmittance second, and the synchronous state of temperature and humidity in the detection chamber and pressure in the crankcase, water vapor condensation and airflow disturbance are eliminated to obtain the true oil mist particle concentration event set. The arrival time of oil mist is determined by the scattering precursor time of the actual oil mist particle concentration event set, and the source of oil mist is inverted by combining the ventilation path adjacency relationship corresponding to the node location identifier, the arrival order of adjacent nodes and the airflow direction corresponding to the crankcase pressure, so as to obtain the oil mist hazard location result. Based on the oil mist hazard location results, the continuity of actual oil mist particle concentration events, changes in engine oil temperature, and the overall oil mist concentration state corresponding to the same-direction oil mist response, hierarchical alarm control is performed to obtain the diesel engine oil mist concentration alarm control results.

2. The diesel engine oil mist concentration alarm control method based on multi-sensor fusion as described in claim 1, characterized in that: The process of obtaining the oil mist concentration detection frame specifically includes: The crankcase, main bearing area, connecting rod bearing area, gear transmission area, and oil return chamber are designated as oil mist detection sites, and each oil mist detection site is configured with a corresponding oil mist detection node and node position identifier; the node position identifier includes a detection site identifier and a ventilation path identifier; The light scattering signal, light transmittance signal, detection chamber temperature and humidity, crankcase pressure and oil temperature of each oil mist detection node are collected according to a unified sampling clock to obtain the node synchronous sampling group; By matching the node synchronous sampling group with the node location identifier according to the sampling time and node order, an oil mist concentration detection frame is obtained.

3. The diesel engine oil mist concentration alarm control method based on multi-sensor fusion as described in claim 2, characterized in that: The process of converting the light scattering signal and light transmittance signal in the oil mist concentration detection frame into a co-directional oil mist response specifically includes: Select non-alarm stable sampling segments from the oil mist concentration detection frame, and determine the light scattering benchmark and light transmittance benchmark from the non-alarm stable sampling segments to obtain the optical benchmark group; The enhancement of the light scattering signal relative to the light scattering reference is determined as the scattering oil mist response quantity, and the scattering oil mist response sequence is obtained; The attenuation of the light transmittance reference relative to the light transmittance signal is determined as the transmittance oil mist response, and the transmittance oil mist response sequence is obtained. By matching the scattered oil mist response sequence and the transmittance oil mist response sequence according to the sampling time, the same-direction oil mist response quantity with the same response direction when the oil mist concentration increases is obtained.

4. The diesel engine oil mist concentration alarm control method based on multi-sensor fusion as described in claim 3, characterized in that: The obtained candidate oil mist mutation event sequence specifically includes: The direction of change of scattering response and the direction of change of transmittance response at adjacent sampling times are determined by the same-direction oil mist response, and a dual-channel change direction sequence is obtained; Local variation segments of scattering response that first rise and then fall, and first fall and then rise, are extracted from the dual-channel change direction sequence to obtain scattering subtle reversal segments; Extract the sampling segment adjacent to the scattering fine reversal segment and whose transmittance response changes in the same direction from the dual-channel change direction sequence to obtain the transmittance same-direction change segment; The scattering inversion fragment and the transmittance change fragment are paired according to the sampling time to obtain the initial oil mist mutation fragment; The initial oil mist mutation fragments are compared with the crankcase pressure changes and the continuity of the responses of adjacent nodes. The initial oil mist mutation fragments that are not triggered by the instantaneous disturbance of crankcase pressure and that the adjacent oil mist detection nodes show the same direction of oil mist response changes in sequence within a preset transmission time are retained to obtain the candidate oil mist mutation event sequence.

5. The diesel engine oil mist concentration alarm control method based on multi-sensor fusion as described in claim 4, characterized in that: The step of performing scattering and transmittance time difference verification on the candidate oil mist mutation event sequence specifically includes: The light scattering response segment and light transmittance response segment corresponding to each candidate oil mist mutation event are extracted from the candidate oil mist mutation event sequence to obtain a dual-channel event segment; The scattering lead time is obtained by calibrating the sampling time of the first continuous enhancement and the first subtle reversal of the scattering response within the dual-channel event segment; The sampling time of the first continuous decay of transmittance response is determined by calibrating the sampling time sequence along the same dual-channel event segment, and the transmittance is obtained after time. The oil mist evolution matching result is obtained by comparing the interval between the scattering advance time and the transmittance subsequent time with the preset time range of the oil mist particles from the fine scattering state to the overall shading state. The oil mist evolution matching results, the temperature and humidity status of the detection chamber, and the synchronous status of the crankcase pressure are combined and verified. Candidate oil mist mutation events with scattering first, transmittance second, and detection chamber temperature and humidity not meeting condensation conditions and crankcase pressure not being synchronously impacted are retained to obtain the true oil mist particle concentration event set.

6. The diesel engine oil mist concentration alarm control method based on multi-sensor fusion as described in claim 5, characterized in that: The process of combining and verifying the oil mist evolution matching results, the humidity status of the detection chamber, and the synchronous pressure status of the crankcase specifically includes: Candidate oil mist mutation events that are subsequently valid but scattering is missing and the humidity of the detection chamber meets the condensation condition are marked as water vapor condensation interference. Candidate oil mist abrupt events that occur simultaneously with crankcase pressure shocks and exhibit a lack of continuity in responses at adjacent nodes are labeled as airflow disturbances. To obtain the attributes of real oil mist particle concentration events, we associate the scattering precedence time, transmittance follow-up time, event duration, and corresponding oil mist detection node with each real oil mist particle concentration event in the real oil mist particle concentration event set.

7. The diesel engine oil mist concentration alarm control method based on multi-sensor fusion as described in claim 6, characterized in that: Determining the arrival time of the oil mist specifically includes: The scattering precursor time in the actual oil mist particle concentration event attribute is determined as the oil mist arrival time of the corresponding oil mist detection node, thus obtaining the node oil mist arrival time table; The node position identifiers are mapped to the ventilation paths between the crankcase, main bearing area, connecting rod bearing area, gear transmission area, and oil return chamber to obtain the adjacency relationship of the ventilation paths; The arrival timetable of oil mist at the nodes is sorted according to the adjacency relationship of the ventilation path to obtain the arrival order of adjacent nodes; By mapping the direction of crankcase pressure change to the adjacency relationship of the ventilation path, the airflow direction is identified. The basic data for oil mist source inversion consists of the arrival order of adjacent nodes and the airflow direction identifier.

8. The diesel engine oil mist concentration alarm control method based on multi-sensor fusion as described in claim 7, characterized in that: The sources of the inverted oil mist specifically include: The candidate source node group is obtained by selecting the oil mist detection node with the earliest oil mist arrival time and its adjacent detection node upstream along the airflow direction from the basic data of oil mist source inversion. The ventilation path sequence from each candidate source node in the candidate source node group to the responding oil mist detection node is determined to obtain the candidate propagation sequence; The candidate propagation order is compared with the arrival order of adjacent nodes one by one to obtain the propagation order matching result; The propagation sequence matching result is compared with the airflow direction identifier to determine the consistency of the direction, thus obtaining the source node determination result. When there are multiple candidate source nodes in the source node determination result, the corresponding relationship between the scattering advance time, transmittance and duration and oil temperature is compared in turn to obtain the target source node. The diesel engine part corresponding to the target source node is identified as the abnormal source part, and the ventilation path sequence from the target source node to the oil mist detection node that has responded is determined as the direction of oil mist diffusion, thus obtaining the oil mist hazard location result.

9. The diesel engine oil mist concentration alarm control method based on multi-sensor fusion as described in claim 8, characterized in that: The implementation of hierarchical alarm control specifically includes: Extract the abnormal source location, oil mist diffusion direction, and associated detection nodes from the oil mist hazard location results to obtain alarm location information; Based on the actual oil mist particle concentration event set corresponding to the oil mist hazard location results, the number of events occurring at the same abnormal source location and the interval between adjacent events are statistically analyzed to obtain the continuity of actual oil mist particle concentration events. The oil temperature change state is determined by the change in oil temperature before and after a real oil mist particle concentration event, thus obtaining the temperature auxiliary state. The overall oil mist concentration state is determined based on the same-direction oil mist response, and the concentration auxiliary state is obtained. By matching the alarm location information, the continuity of actual oil mist particle concentration events, temperature auxiliary status and concentration auxiliary status, the early warning level, alarm level and shutdown protection level are obtained. By correlating the early warning level, alarm level, and shutdown protection level with the location of the abnormal source, the direction of oil mist diffusion, the associated detection nodes, and the alarm time, the alarm control results for diesel engine oil mist concentration are obtained.

10. A diesel engine oil mist concentration alarm control system based on multi-sensor fusion, based on the diesel engine oil mist concentration alarm control method based on multi-sensor fusion as described in any one of claims 1 to 9, characterized in that: include, The synchronous acquisition module synchronously acquires the light scattering signal, light transmittance signal, detection chamber temperature and humidity, crankcase pressure, engine oil temperature and node position identifier of each oil mist detection node, and aligns them according to a unified sampling clock to obtain the oil mist concentration detection frame; The event filtering module converts the light scattering signal and light transmittance signal in the oil mist concentration detection frame into the same-direction oil mist response quantity, and combines the crankcase pressure and the continuity of the response of adjacent nodes to filter out subtle scattering reversals and same-direction transmittance changes, thus obtaining candidate oil mist mutation event sequences. The time difference verification module performs scattering and transmittance time difference verification on the candidate oil mist mutation event sequence. Based on the principle of scattering first, transmittance second, and the synchronous state of temperature and humidity in the detection chamber and crankcase pressure, water vapor condensation and airflow disturbance are eliminated to obtain the true oil mist particle concentration event set. The source inversion module determines the arrival time of oil mist by the scattering precedence time of the real oil mist particle concentration event set, and inverts the source of oil mist by combining the ventilation path adjacency relationship corresponding to the node position identifier, the arrival order of adjacent nodes and the airflow direction corresponding to the crankcase pressure, and obtains the oil mist hazard location result. The hierarchical control module performs hierarchical alarm control based on the oil mist hazard location results, the continuity of actual oil mist particle concentration events, changes in engine oil temperature, and the overall oil mist concentration state corresponding to the same-direction oil mist response, thereby obtaining the diesel engine oil mist concentration alarm control results.

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