A self-cleaning desert air filter, vehicle and a self-cleaning method

Abstract

The application discloses a self-cleaning desert air filter, a vehicle and a self-cleaning method, and belongs to the air filter field.The technical scheme is as follows: a self-cleaning desert air filter comprises an air filter main body, the air filter main body comprises an air filter shell, a filtering assembly and a cleaning assembly are arranged in the air filter shell, the cleaning assembly comprises a fan, an air suction pipe is connected to an air inlet of the fan, one end of the air suction pipe away from the fan extends into the air filter shell and is close to the filtering assembly, an air outlet of the fan is connected with a dust discharge pipe, and the dust discharge pipe extends out of the air filter shell; a controller is further arranged, a negative pressure sensor is arranged in the air filter shell, the negative pressure sensor is electrically connected with the controller, and the negative pressure sensor is used for controlling the fan.The controller automatically controls the fan to start and stop according to the negative pressure signal by detecting the blocking degree of the filtering assembly through the negative pressure sensor, automatic sensing and cleaning of the air filter blocking state are realized, and the maintenance frequency and labor intensity in a high-dust desert environment are obviously reduced.

Description

Technical Field

[0001] This invention relates to the field of air filters, and in particular to a self-cleaning desert air filter, a vehicle, and a self-cleaning method. Background Technology

[0002] Deserts, Gobi, and other sandy areas are typical operating grounds for special off-road vehicles and engineering vehicles. The air contains a large amount of fine sand and dust impurities, requiring the engine's intake system to continuously filter the intake air through an air filter. The supply of clean air directly affects the engine's operational stability and lifespan. Dust buildup and clogging of the air filter element increases intake negative pressure, leading to decreased engine power, increased fuel consumption, and in severe cases, direct engine shutdown and interruption of operations. Therefore, the continuous cleaning capability of the air filter element under sandy conditions is a key design indicator for special vehicles.

[0003] Existing vehicle air filters adapted to desert conditions are generally equipped with a pre-filter swirl structure and an automatic backflushing device. The backflushing device relies on the vehicle's air source to perform filter element blowing operations uniformly after the vehicle is turned off. It completes dust cleaning by relying on a fixed sequence. The entire blowing process is linked to the engine start-stop action and is currently a widely equipped intake filtration system for special vehicles in the field.

[0004] The fixed-time, uniform purging mode has several drawbacks. Every time the vehicle is turned off, the filter is cleaned, and the filter is frequently subjected to airflow impacts. Long-term use will accelerate filter material wear and shorten the filter replacement cycle. At the same time, the purging is carried out after the vehicle is turned off. If the vehicle is running for a long time, it cannot be effectively cleaned during the running period, which can easily lead to the rapid accumulation of dust in the air filter, a decrease in engine intake air volume, and a serious impact on engine operating conditions. Summary of the Invention

[0005] This invention addresses the problem that current special vehicles only clean their air filters after the engine is turned off, resulting in severe dust accumulation during prolonged engine operation. It provides a self-cleaning desert air filter that can be cleaned at any time.

[0006] A self-cleaning desert air filter includes an air filter body, which includes an air filter housing. The air filter housing contains a filter assembly and a cleaning assembly. The cleaning assembly includes a fan, with an air inlet connected to a suction pipe. The end of the suction pipe furthest from the fan extends into the air filter housing and near the filter assembly. The air outlet of the fan is connected to a dust discharge pipe that extends to the outside of the air filter housing. The air filter body also includes a controller. The air filter housing contains a negative pressure sensor, which is electrically connected to the controller and used to control the fan. By placing a negative pressure sensor inside the air filter housing, the degree of clogging of the filter components can be detected accurately in real time. The suction pipe extends into the housing and is close to the filter components, ensuring that the negative pressure suction acts directly on the dust accumulation area. The dust exhaust pipe directly discharges the dust to the outside of the housing, avoiding secondary pollution. The controller automatically controls the start and stop of the fan based on the negative pressure signal, realizing automatic detection and cleaning of the air filter clogging status. Cleaning and maintenance can be completed without manual disassembly of the filter element, significantly reducing the frequency of maintenance and labor intensity in the high dust environment of the desert.

[0007] Preferably, the filtration assembly includes a pre-filter connected to a main filter element. The pre-filter is located on the upper exterior of the air filter housing, and the main filter element is disposed inside the air filter housing. A safety filter element is nested inside the main filter element. The pre-filter, located on the upper exterior of the housing, pre-separates large particles of sand and dust before the air enters the housing, reducing the filtration burden on the main filter element. The safety filter element, nested inside the main filter element, provides additional protection when the main filter element is damaged or replaced, preventing unfiltered dusty air from directly entering the engine. This forms a triple protection system, significantly improving filtration reliability under harsh desert conditions.

[0008] Preferably, the pre-filter includes an air inlet duct with a swirling device inside. The air outlet of the air inlet duct is connected to the main filter element. A one-way dust discharge valve is also provided at the bottom of the air inlet duct, located below the swirling device. Utilizing centrifugal force, large particles of sand and dust are efficiently separated before air enters the main filter element, significantly extending the lifespan of the main filter element. The one-way dust discharge valve, located below the swirling device, automatically discharges the separated sand and dust from the air inlet duct using gravity. The one-way structure prevents backflow of external sand and dust, achieving a self-discharge function for the pre-filter without manual intervention, making it particularly suitable for continuous operation environments in deserts.

[0009] Preferably, the controller is also connected to a forced start switch. Operators can force the fan to start for emergency cleaning with a single button, avoiding engine power reduction or shutdown due to automatic control failure, thus improving the system's reliability and emergency response capabilities under extreme conditions.

[0010] On the other hand, the present invention also provides a vehicle that uses the aforementioned self-cleaning desert air filter. Vehicles using the aforementioned self-cleaning desert air filter do not require frequent manual cleaning of the filter element in desert or dusty environments. The controller automatically senses the degree of clogging and performs cleaning, ensuring that the engine intake resistance is always maintained within a reasonable range, effectively reducing fuel consumption, improving engine power output stability and vehicle uptime, and significantly reducing the frequency of filter element replacement and maintenance costs.

[0011] Thirdly, the present invention also provides a self-cleaning method for the above-mentioned self-cleaning desert air filter, comprising the following steps: S1. The controller collects negative pressure values ​​when the engine is running stably, and determines the current clogging level of the filter component based on the difference between the collected negative pressure value and the reference value. The clogging level includes at least mild clogging, moderate clogging, and severe clogging. The reference value is the negative pressure value recorded after the last cleaning and set time of rest, and is updated by the controller based on the current actual negative pressure value after each cleaning. S2. Based on the blockage level determined in S1, the controller matches the fan operating intensity and reference operating time corresponding to the blockage level, and starts the fan to purge and clean the air filter; S3. During the operation of the fan, the controller continuously collects negative pressure values ​​in real time through the negative pressure sensor. The controller takes the absolute value of the collected negative pressure value as the current pressure difference and determines whether to terminate the operation of the fan in advance based on the rate of decrease of the pressure difference and the deviation between the current pressure difference and the reference pressure difference value. If the early termination condition is not met, the fan continues to run until the reference running time is exhausted and then stops. The reference pressure difference value is the clean reference pressure difference value initially calibrated by the system.

[0012] This method is based on matching the different operating intensity and duration of the fan according to the clogging level, avoiding the problem of over-cleaning at low levels or under-cleaning at high levels caused by uniform cleaning intensity; it introduces the differential pressure drop rate as a closed-loop feedback criterion to realize dynamic termination decision during the cleaning process, and stops the machine in advance when the cleaning effect reaches the expected level, avoiding irreversible damage to the filter element caused by over-cleaning; the benchmark value is automatically updated after each cleaning, so that the system has the ability to adapt and dynamically adjust the judgment benchmark according to the performance degradation of the filter element throughout its life cycle, and always maintain the optimal control accuracy.

[0013] Furthermore, in step S1: The controller simultaneously collects the engine speed signal and the speed change per unit time. When the speed is between 70% and 90% of the rated speed, and the fluctuation of the engine speed within any 3-second window is less than 30 revolutions per second, the controller determines that it is in a stable operating condition and executes subsequent steps. The controller internally presets three differential pressure boundary values ​​A, B, and C, where A < B < C. It calculates the difference ΔS = Pc between the collected negative pressure value and the reference value. Pb, where Pc is the real-time negative pressure value collected by the negative pressure sensor at the current moment, and Pb is the baseline value recorded after standing for 5 seconds after the last cleaning; the blockage level is determined according to the range in which the difference ΔS falls: the difference between A and B is a light blockage, the difference between B and C is a moderate blockage, and the difference exceeding C is a severe blockage. When the difference ΔS between the collected negative pressure value and the reference value has not yet reached the boundary value A, the controller calculates the rate of increase of the pressure difference, that is, the rate of increase of the negative pressure value Pc relative to the reference value Pb. If the rate exceeds 0.15 kPa / s, the controller marks the state as ready for cleaning in advance.

[0014] By simultaneously collecting both the absolute value of engine speed and the amplitude of its fluctuations to determine stable operating conditions, the system effectively filters out the interference of transient conditions such as rapid engine acceleration, deceleration, and idling fluctuations on negative pressure sampling, ensuring the accuracy and consistency of blockage level determination. The three-level blockage gradient threshold quantifies the degree of blockage into three distinct levels, avoiding the problems of frequent start-stop or slow response caused by a single threshold. The introduction of the differential pressure rise rate as a predictive indicator allows for the early identification of rapid blockage trends and the marking of a preparatory cleaning state before the differential pressure reaches the minimum threshold, achieving an upgrade from passive response to proactive prediction, which is especially suitable for extreme scenarios such as sandstorms where dust concentrations suddenly increase.

[0015] Furthermore, in step S2: The controller defines the current differential pressure deviation as E(t) = P(t). Pb, where P(t) is the real-time negative pressure value collected by the negative pressure sensor at the current time t, and Pb is the baseline value recorded after the last cleaning; the first-order rate of change of pressure difference is defined as R(t) = dE(t) / dt, that is, the rate of decrease of pressure difference, in kPa / s; the second-order rate of change of pressure difference is defined as A(t) = d²E(t) / dt², that is, the acceleration of the rate of decrease of pressure difference, in kPa / s². The controller determines the initial duty cycle D0 of the fan based on the blockage level determined by S1. When the congestion level is light, D0 = 60%; When the congestion level is moderate, D0 = 80%; When the congestion level is severe, D0 = 100%; After the fan starts, the controller performs periodic sampling and calculation. In each period, the controller updates the duty cycle D. When R(t) < 0.02 kPa / s and A(t) ≥ 0 kPa / s², it indicates that the current differential pressure decreases extremely slowly or even stagnates, and there is no accelerating downward trend. The cleaning efficiency is insufficient, and the controller executes an upward adjustment strategy: D(t+1) = min(D(t) + 5%, 100%), where D(t+1) is the duty cycle of the next adjustment cycle, and D(t) is the duty cycle of the current adjustment cycle. When R(t) > 0.06 kPa / s and A(t) ≤ 0 kPa / s², the controller executes a down-adjustment strategy: D(t+1) = max(D(t)). 3%, 50%); When R(t) > 0.06 kPa / s and A(t) > 0 kPa / s², the controller executes a fast down-adjustment strategy: D(t+1) = max(D(t)). 5%, 50%); When 0.02 kPa / s ≤ R(t) ≤ 0.06 kPa / s, the controller maintains the current duty cycle unchanged, i.e., D(t+1) = D(t); In each formula, the min and max functions are used to limit the upper and lower boundary values ​​of the duty cycle, respectively, with the upper limit of the duty cycle being 100% and the lower limit being 50%.

[0016] A dual-dimensional dynamic feedback system is constructed by introducing first-order and second-order differential pressure change rates to achieve refined control of the cleaning process. The first-order change rate reflects the current cleaning efficiency level, while the second-order change rate reflects the trend of cleaning efficiency changes. Based on the combination of the first-order and second-order change rates, four differentiated duty cycle adjustment strategies—upward adjustment, downward adjustment, rapid downward adjustment, and maintenance—are formulated to ensure that the fan intensity can match the cleaning response characteristics of the filter element in real time. The upward adjustment strategy ensures that the intensity is automatically increased to overcome stubborn dust accumulation when cleaning is difficult. The downward adjustment strategy actively reduces the intensity when the cleaning effect is significant to avoid the filter element fibers being subjected to unnecessary impact loads. The rapid downward adjustment strategy quickly reduces the power output for cleaning scenarios with extremely high efficiency, minimizing energy waste and excessive stress on the filter element, while further extending the service life of the filter element.

[0017] Furthermore, in step S3: During fan operation, the negative pressure sensor continuously collects the negative pressure value P(t) in real time and sends it to the controller. The controller takes the absolute value of this negative pressure value as the current pressure difference, compares the current pressure difference with the reference pressure difference value, and calculates the deviation ΔPa = |P(t)|. Pr, where Pr is the reference differential pressure value in S1; The conditions for early termination of the fan operation are: the deviation ΔPa has dropped to within ±5% of Pr, and the rate of decrease of the differential pressure R(t) is less than 0.08 kPa / s, where R(t) = dP(t) / dt. The controller stops the fan operation when both conditions are met. After each cleaning cycle, the controller records the current actual negative pressure value and updates it to the reference value used in the next S1 step, i.e., updates Pb. If this cleaning cycle is the first run or the reference value has not been initialized, the controller uses the average of 10 consecutive negative pressure values ​​collected after the engine is first started and running stably as the initial reference value. After the reference value is updated, the controller stores the highest negative pressure value, the final negative pressure value, and the actual running time recorded during this cleaning process in its internal memory for subsequent reference value correction.

[0018] The system employs a dual-condition approach, combining the absolute value of the deviation and the rate of descent, to determine early termination. The former ensures that the differential pressure has recovered to near-absolute cleanliness, while the latter confirms that the cleaning trend has stabilized. Both conditions must be met simultaneously for the system to shut down, preventing premature termination or over-cleaning due to misjudgment caused by a single condition. The baseline value is automatically updated after cleaning, enabling the system to track baseline drift caused by fiber aging and irreversible clogging throughout the filter cartridge's lifespan, maintaining consistent accuracy. Storing multiple cleaning data sets provides a data foundation for subsequent weighted corrections, giving the system long-term self-learning and adaptive capabilities. Receiving baseline values ​​after a set set set time avoids interference from airflow disturbances on measurement accuracy, ensuring the reliability and repeatability of the baseline values.

[0019] Furthermore, it includes the addition of a forced start switch. When the forced start switch is activated, the fan starts directly to clean the filter components. Operators can bypass the automatic judgment logic and directly start the fan for emergency cleaning, improving the system's fault tolerance and emergency response capabilities in the desert environment. This ensures that the vehicle can maintain basic operational capabilities even in extreme conditions, providing a guarantee for the vehicle to leave dangerous areas or reach a repair station.

[0020] As can be seen from the above technical solutions, the beneficial effects of this invention are as follows: This self-cleaning desert air filter uses a negative pressure sensor inside the housing to monitor the degree of clogging of the filter components in real time. The controller automatically starts and stops the fan based on the negative pressure signal. The dust suction pipe is close to the filter components to suck up the accumulated dust, and the dust discharge pipe discharges the dust outward, preventing secondary dust from being generated inside the housing. Automatic cleaning can be completed without manual disassembly of the filter element, significantly reducing the frequency of maintenance and the intensity of manual labor under high dust conditions in the desert. The filter component adopts a triple protection structure of an external pre-filter, an internal main filter element, and a safety filter element embedded in the main filter element. The pre-filter uses a cyclone device to centrifugally separate large particles of sand and dust to reduce the load on the main filter element. The bottom one-way dust discharge valve can automatically discharge dust and prevent sand and dust backflow. The safety filter element blocks dust when the main filter element fails, significantly improving the filtration reliability in harsh environments. The controller is equipped with a forced start switch that can start the fan with one button in an emergency, avoiding the risk of engine failure caused by automatic control failure. Vehicles equipped with this air filter can continuously and stably control the engine intake resistance, reduce fuel consumption, and stabilize power output. This system reduces filter replacement costs and improves vehicle uptime. The self-cleaning method determines stable operating conditions based on engine speed and fluctuations, avoiding transient interference and ensuring accurate negative pressure sampling. It classifies clogging levels into mild, moderate, and severe using three-level differential pressure thresholds, and predicts rapid clogging trends based on differential pressure rise rate, adapting to scenarios with sudden increases in dust during sandstorms. Different clogging levels are matched with corresponding initial fan duty cycles, and the fan power is dynamically adjusted based on the first and second order rates of differential pressure change. It automatically increases intensity when cleaning resistance is high and gradually reduces power when cleaning is effective, minimizing filter impact damage and energy loss. During cleaning, it relies on differential pressure deviation and differential pressure drop rate to determine early shutdown, preventing over-cleaning damage to the filter. After each cleaning cycle, the controller automatically updates the baseline value and stores historical cleaning data, adaptively determining cleaning based on filter aging. The entire solution accommodates automatic routine cleaning and manual emergency cleaning, meeting the long-term continuous operation needs of desert vehicles, effectively extending filter life and improving engine stability. Attached Figure Description

[0021] To more clearly illustrate the technical solution of this patent, the drawings used in the description will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this patent. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0022] Figure 1 This is a structural schematic diagram of a specific embodiment of the invention.

[0023] Figure 2 This is a schematic diagram of the structure of the filter component in a specific embodiment of the present invention.

[0024] Figure 3 This is a schematic diagram of the pre-filter in a specific embodiment of the present invention.

[0025] Figure 4 This is a schematic diagram of the cleaning component in a specific embodiment of the present invention.

[0026] Figure 5 This is a schematic diagram of the controller connection in a specific embodiment of the present invention.

[0027] Explanation of main figure symbols 1. Air filter body, 2. Cleaning assembly, 3. Air filter housing, 4. Pre-filter, 5. Main filter element, 6. Safety filter element, 7. Air inlet, 8. Cyclone device, 9. One-way dust discharge valve, 10. Fan, 11. Dust discharge pipe, 12. Controller, 13. Negative pressure sensor, 14. Forced start switch, 15. Relay, 16. Replacement indicator light, 17. Suction pipe. Detailed Implementation

[0028] To make the objectives, features, and advantages of this patent more apparent and understandable, the technical solutions of this patent will be clearly and completely described below with reference to the accompanying drawings of the specific embodiments. Obviously, the embodiments described below are only some embodiments of this patent, and not all embodiments. Based on the embodiments of this patent, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this patent.

[0029] Example 1 like Figure 1-4 As shown, a self-cleaning desert air filter includes an air filter body 1, which includes an air filter housing 3. A filter assembly and a cleaning assembly 2 are synchronously assembled inside the air filter housing 3. The cleaning assembly 2 includes a fan 10. The air inlet of the fan 10 is sealed and connected to a dust collection pipe 17. One end of the dust collection pipe 17, away from the fan 10, extends through the side wall of the air filter housing 3 into the housing. The opening of the dust collection pipe 17 is arranged close to the filter assembly. The air outlet of the fan 10 is connected to a dust discharge pipe 11, which extends outward from the air filter housing 3, allowing the sucked dust to be directly discharged outside the housing. The equipment is equipped with a controller 12. A negative pressure sensor 13 is fixedly installed inside the air filter housing 3. The negative pressure sensor 13 is electrically connected to the controller 12 via a wire. The negative pressure signal collected by the negative pressure sensor 13 is transmitted to the controller 12, and the controller 12 controls the fan 10 to start and stop based on the signal value.

[0030] The filter assembly includes a pre-filter 4 and a main filter element 5. The pre-filter 4 is arranged on the outer side of the upper end of the air filter housing 3. The air outlet of the pre-filter 4 is sealed and connected to the main filter element 5. The main filter element 5 is installed inside the air filter housing 3. A safety filter element 6 is nested inside the cavity of the main filter element 5. The safety filter element 6 is completely surrounded by the main filter element 5.

[0031] The pre-filter 4 includes an air inlet 7, with a cyclone device 8 fixedly mounted inside the air inlet 7. A one-way dust discharge valve 9 is installed at the bottom of the air inlet 7 and is located directly below the cyclone device 8. The controller 12 is connected to a forced start switch 14 via an external line. The operator can directly send a signal to the controller 12 by operating the forced start switch 14 to force the fan 10 to start the cleaning operation.

[0032] like Figure 5 As shown, the controller 12 is powered by a 24V DC vehicle power supply. The 24V power supply of the vehicle is first split into two paths through a fuse. One path is connected to the power supply pin of the controller 12 to power the controller, and the other path is connected to the normally open contact main circuit of the relay 15 to supply power to the motor of the fan 10. The controller 12 has multiple sets of input and output wiring ports. The input ports are respectively connected to the external engine speed signal, the negative pressure sensor 13, the forced start switch 14, and the common ground terminal. The negative pressure sensor 13 collects negative pressure data in real time and transmits it to the controller. The engine speed signal is used to identify the engine operating status. One end of the forced start switch 14... One end of the controller is grounded and connected to the controller. The controller can be manually sent a forced operation command. One output of the controller is connected to the coil of relay 15. The other end of the relay coil is grounded. When the controller determines that the motor needs to be started based on the negative pressure and speed signals, the output level energizes the relay coil and closes the normally open contact. The 24V power supply is transmitted to the motor through the closed contact. The lower end of the motor is grounded to form a complete power circuit to complete the operation and realize the operation of the fan 12. The other output of the controller is connected to the replacement indicator light 16. The lower end of the indicator light is grounded. When the controller detects an abnormal negative pressure (damaged filter element), the output signal lights up the indicator light to remind the operator.

[0033] Example 2 This embodiment further provides a vehicle that uses the self-cleaning desert air filter provided in Embodiment 1.

[0034] Example 3 This embodiment provides a self-cleaning method for a self-cleaning desert air filter according to Embodiment 1, including the following steps: S1, the controller 12 collects negative pressure values ​​when the engine is in stable operating condition, and determines the current clogging level of the filter component based on the difference between the collected negative pressure value and the reference value. The clogging level includes at least mild clogging, moderate clogging and severe clogging. The reference value is the negative pressure value recorded after a set time of rest following the last cleaning, and is updated by the controller 12 based on the current actual negative pressure value after each cleaning to achieve automatic tracking of the performance degradation of the filter component throughout its life cycle.

[0035] The controller 12 determines that the engine is in a stable operating condition by simultaneously collecting the engine speed signal and its speed change per unit time. When the speed is between 70% and 90% of the rated speed, and the fluctuation range of the engine speed within any 3-second window is less than 30 revolutions per second, the controller 12 determines it to be in a stable operating condition and executes subsequent steps. By simultaneously collecting both the absolute value of the speed and the fluctuation range to determine the stable operating condition, the interference of transient conditions such as rapid acceleration, rapid deceleration, and idling fluctuations on the negative pressure sampling can be effectively filtered out, ensuring the accuracy and consistency of the blockage level determination.

[0036] The controller 12 has three preset differential pressure boundary values ​​A, B, and C, where A < B < C. The difference ΔS = Pc between the collected negative pressure value and the reference value is calculated. Pb, where Pc is the real-time negative pressure value collected by negative pressure sensor 13 at the current moment, and Pb is the baseline value recorded after 5 seconds of settling following the last cleaning; the blockage level is determined based on the range in which the difference ΔS falls: a difference between A and B indicates mild blockage, a difference between B and C indicates moderate blockage, and a difference exceeding C indicates severe blockage. The three-level blockage gradient threshold quantifies the degree of blockage into three distinct levels, avoiding frequent start-stop or sluggish response issues caused by a single threshold.

[0037] When the difference ΔS between the collected negative pressure value and the reference value has not yet reached the boundary value A, the controller 12 calculates the rate of increase of the pressure difference, that is, the rate of increase of the negative pressure value Pc relative to the reference value Pb. If this rate exceeds 0.15 kPa / s, the controller 12 marks it as a preparatory cleaning state in advance, and will preferentially enter S2 when other conditions are met subsequently. Introducing the rate of increase of the pressure difference as a predictive indicator allows for the early identification of rapid clogging trends and the marking of a preparatory cleaning state before the difference reaches the minimum threshold, achieving an upgrade from passive response to proactive prediction, which is especially suitable for extreme scenarios such as sandstorms where dust concentration suddenly increases.

[0038] In step S2, the controller 12 matches the operating intensity and baseline operating time of the fan 10 corresponding to the blockage level determined in step S1, and starts the fan 10 to purge and clean the air filter. By matching differentiated fan operating intensity and duration based on blockage level classification, the problem of over-cleaning at low levels or under-cleaning at high levels caused by uniform cleaning intensity can be avoided, achieving precise cleaning on demand.

[0039] The operating intensity of fan 10 is dynamically adjusted. The specific adjustment process is as follows: Controller 12 defines the current differential pressure deviation E(t) = P(t). Pb, where P(t) is the real-time negative pressure value collected by negative pressure sensor 13 at the current time t, and Pb is the baseline value recorded after the last cleaning. The first-order rate of change of pressure difference is defined as R(t) = dE(t) / dt, which is the rate of decrease in pressure difference, in kPa / s. The second-order rate of change of pressure difference is defined as A(t) = d²E(t) / dt², which is the acceleration of the rate of decrease in pressure difference, in kPa / s². Introducing the first-order and second-order rates of change constitutes a two-dimensional dynamic feedback system. The first-order rate of change reflects the current cleaning efficiency, while the second-order rate of change reflects the trend of change in cleaning efficiency, achieving refined control of the cleaning process.

[0040] The controller 12 determines the initial duty cycle D0 of the fan 10 based on the blockage level determined by S1: when the blockage level is light blockage, D0=60%; when the blockage level is moderate blockage, D0=80%; when the blockage level is heavy blockage, D0=100%.

[0041] After the fan 10 starts, the controller 12 samples and calculates at a cycle of 1 second. In each adjustment cycle, the controller 12 updates the duty cycle D according to the following multi-condition comprehensive judgment rule: When R(t) < 0.02 kPa / s and A(t) ≥ 0 kPa / s², it indicates that the current pressure difference decreases extremely slowly or even stagnates, and there is no accelerating downward trend, indicating insufficient cleaning efficiency. Controller 12 executes an upward adjustment strategy: D(t+1) = min(D(t) + 5%, 100%), where D(t+1) is the duty cycle of the next adjustment cycle and D(t) is the duty cycle of the current adjustment cycle. The upward adjustment strategy ensures that the intensity is automatically increased when cleaning is difficult to overcome stubborn dust accumulation. When R(t) > 0.06 kPa / s and A(t) ≤ 0 kPa / s², it indicates that the current pressure difference decreases rapidly but is showing a decelerating trend. The cleaning effect is significant, but the efficiency is decreasing. To prevent over-cleaning while retaining a cleaning margin, controller 12 executes a down-adjustment strategy: D(t+1) = max(D(t)). (3%, 50%), when the cleaning effect is significant, the strength is actively reduced to avoid the filter fiber bearing unnecessary impact load; When R(t) > 0.06 kPa / s and A(t) > 0 kPa / s², it indicates that the current differential pressure is decreasing rapidly and is still accelerating, the filter component is cleaning very efficiently, and controller 12 executes a rapid adjustment strategy: D(t+1) = max(D(t)). (5%, 50%), to quickly reduce the strength of the fan 10 to a reasonable level, avoiding energy waste and excessive stress on the filter components; When 0.02 kPa / s ≤ R(t) ≤ 0.06 kPa / s, it indicates that the current differential pressure decrease rate is within the ideal range, the cleaning efficiency is moderate, and the controller 12 maintains the current duty cycle unchanged, i.e., D(t+1) = D(t).

[0042] In the above formulas, the min and max functions are used to limit the upper and lower boundary values ​​of the duty cycle, respectively, with an upper limit of 100% and a lower limit of 50%. The entire dynamic adjustment mechanism formulates four differentiated duty cycle adjustment strategies—upward adjustment, downward adjustment, rapid downward adjustment, and maintenance—based on the combination of the first-order and second-order rates of change. This allows the fan intensity to match the cleaning response characteristics of the filter element in real time, and is expected to save 20% to 30% energy compared to the traditional fixed duty cycle solution, while further extending the service life of the filter element.

[0043] S3, during the operation of the fan 10, the controller 12 continuously collects negative pressure values ​​in real time through the negative pressure sensor 13. The controller 12 takes the absolute value of the collected negative pressure value as the current differential pressure and determines whether to terminate the operation of the fan 10 in advance based on the rate of decrease of the differential pressure and the deviation between the current differential pressure and the reference differential pressure value. If the early termination condition is not met, the fan 10 continues to run until the reference running time is exhausted and then stops. The reference differential pressure value is the cleaning reference differential pressure value Pr initially calibrated by the system, representing the standard differential pressure value of the air filter in a brand-new clean state. This value is a fixed calibration value and remains unchanged throughout the entire service life of the filter component. Introducing the rate of decrease of the differential pressure as a closed-loop feedback criterion realizes dynamic termination decision during the cleaning process. When the cleaning effect reaches the expected level, the machine stops in advance to avoid irreversible damage to the filter element caused by over-cleaning. This upgrades the traditional timed and frequencyd cleaning to on-demand precise cleaning, which is expected to extend the service life of the filter element by 30% to 50%.

[0044] During the operation of the fan 10, the negative pressure sensor 13 continuously collects the negative pressure value P(t) in real time and sends it to the controller 12. The controller 12 takes the absolute value of the negative pressure value as the current pressure difference, compares the current pressure difference with the reference pressure difference value, and calculates the deviation ΔPa=|P(t)|. Pr.

[0045] The conditions for early termination of fan 10 are: the deviation ΔPa has dropped to within ±5% of Pr, and the rate of pressure drop R(t) is less than 0.08 kPa / s, where R(t) = dP(t) / dt. When both conditions are met simultaneously, controller 12 immediately stops fan 10. Early termination is determined by a combination of the absolute value of the deviation and the rate of pressure drop. The former ensures that the pressure difference has recovered to near-absolute cleanliness, while the latter confirms that the cleaning trend has stabilized. Both conditions must be met simultaneously for shutdown to avoid premature termination or over-cleaning due to misjudgment of a single condition.

[0046] After each cleaning cycle, controller 12 records the current actual negative pressure value and updates it to the reference value used in the next S1 step, i.e., updates Pb. If this cleaning cycle is the first run or the reference value has not been initialized, controller 12 uses the average of 10 consecutive negative pressure values ​​collected after the engine starts and runs stably for the first time as the initial reference value. After the reference value is updated, controller 12 stores the highest negative pressure value, the final negative pressure value, and the actual running time recorded during this cleaning process in its internal memory for subsequent weighted correction of the reference value. The storage of multiple cleaning data provides a data basis for subsequent weighted correction, enabling the system to have long-term self-learning and adaptive capabilities. The 5-second pause before collecting the reference value avoids the interference of airflow disturbance on measurement accuracy, ensuring the reliability and repeatability of the reference value.

[0047] This method also includes setting a forced start switch 14. When the forced start switch is turned on, the blower 10 starts directly to clean the filter components. The forced start switch provides a manual emergency backup channel for the automatic cleaning method. In the event of automatic control circuit failure, negative pressure sensor 13 malfunction, or sudden severe blockage of the filter element causing a sharp drop in engine power, the operator can bypass the automatic judgment logic and directly start the blower for emergency cleaning, ensuring that the vehicle can still maintain basic operating capabilities under extreme conditions, and providing assurance for the vehicle to leave the danger zone or reach the repair station.

[0048] As can be seen from the above implementation methods, the advantages of this invention are as follows: This solution combines a control scheme that integrates negative pressure sensing, engine speed condition identification, graded self-cleaning logic, and dynamic closed-loop adjustment of the fan duty cycle, along with manual forced start and filter element damage alarm functions, giving it multiple technical advantages. First, the system relies on a negative pressure sensor to monitor the filter element clogging level in real time, and combines the absolute value of engine speed and the amplitude of speed fluctuation to determine stable sampling conditions, effectively avoiding negative pressure sampling errors caused by engine acceleration / deceleration and idling fluctuations. At the same time, it sets three levels of clogging pressure difference thresholds with a pressure difference rise rate prediction mechanism, which can accurately distinguish between light, moderate, and heavy clogging states, and can also identify the rapid clogging trend of the filter element in scenarios such as sandstorms and other sudden increases in dust, achieving proactive predictive cleaning and eliminating the problems of frequent start-stop or delayed cleaning caused by a single threshold. Secondly, the fan cleaning system employs a tiered initial duty cycle matching dual-stage differential pressure change rate dynamic adjustment strategy. Based on the differential pressure decrease rate and its trend, it differentiates between four adjustment modes: upward adjustment, downward adjustment, rapid downward adjustment, and maintenance. This strictly limits the fan duty cycle to the 50%~100% operating range, ensuring the fan output intensity matches the filter dust cleaning efficiency in real time. Compared to a fixed power cleaning solution, this can save 20%~30% energy and reduce unnecessary fan power consumption. Furthermore, a dual-condition early shutdown logic is implemented during the cleaning phase. Combining the clean baseline differential pressure deviation and the differential pressure decrease rate, the system automatically shuts down when the differential pressure returns to the clean standard range and the cleaning rate tends to level off. This avoids prolonged purging impact on the filter fibers, extending filter lifespan by 30%~50%. After each cleaning cycle, the controller automatically updates the clogging judgment baseline value, synchronously storing historical cleaning data for self-learning correction. The baseline value continuously and adaptively updates as the filter ages, eliminating the impact of performance degradation after long-term use on clogging judgment accuracy. The static delay in acquiring the baseline value also avoids airflow disturbance interference, ensuring stable and reliable negative pressure detection data. Meanwhile, the electronic control system integrates a manual forced start switch. In case of automatic control failure, sensor malfunction, or sudden severe blockage of the filter element, the operator can directly force the start of the fan for emergency purging to ensure normal vehicle operation under extreme conditions. The circuit is equipped with a fuse for overcurrent protection, and the replacement indicator light automatically illuminates when the filter element is damaged or the negative pressure is abnormal, promptly reminding maintenance personnel to inspect and replace the filter element. The overall structure combines pre-filter cyclone coarse filtration, main filter element fine filtration, safety filter element protection, and automatic negative pressure backflushing cleaning. The one-way dust discharge valve at the bottom of the pre-filter pre-separates large dust particles, significantly reducing the dust load on the main filter element. The fan's independent dust suction and discharge pipeline directly discharges dust from the housing, avoiding secondary dust adhering to the filter element. The entire set of equipment is suitable for desert high-dust vehicle environments, with a high degree of automation, low energy consumption, and low filter element wear. It combines automatic intelligent control with manual emergency backup, operates stably and reliably, and is suitable for use in various off-road vehicles.

[0049] The above description of the disclosed embodiments enables those skilled in the art to implement or use this patent. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this patent. Therefore, this patent is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A self-cleaning desert air filter, comprising an air filter body (1), characterized in that, The air filter body (1) includes an air filter housing (3), in which a filter assembly and a cleaning assembly are provided. The cleaning assembly (2) includes a fan (10), the air inlet of which is connected to a dust suction pipe (17), the end of which is away from the fan (10) extends into the air filter housing (3) and close to the filter assembly. The air outlet of the fan (10) is connected to a dust discharge pipe (11), which extends to the outside of the air filter housing (3). The air filter body (12) also includes a controller (12), in which a negative pressure sensor (13) is provided. The negative pressure sensor (13) is electrically connected to the controller (12) and is used to control the fan (10).

2. The self-cleaning desert air filter according to claim 1, characterized in that, The filtration assembly includes a pre-filter (4) connected to a main filter element (5). The pre-filter (4) is located outside the upper end of the air filter housing (3), and the main filter element (5) is disposed inside the air filter housing (3). A safety filter element (6) is nested inside the main filter element (5).

3. The self-cleaning desert air filter according to claim 2, characterized in that, The pre-filter (4) includes an air inlet (7), inside which is a swirling device (8). The air outlet of the air inlet (7) is connected to the main filter element (5). A one-way dust discharge valve (9) is also provided at the bottom of the air inlet (7), and the one-way dust discharge valve (9) is located below the swirling device (8).

4. The self-cleaning desert air filter according to claim 1, characterized in that, The controller is also connected to a forced start switch (14).

5. A vehicle, characterized in that, The self-cleaning desert air filter as described in any one of claims 1-4 is used.

6. A self-cleaning method for a self-cleaning desert air filter according to any one of claims 1-4, characterized in that, Includes the following steps: S1. The controller (12) collects negative pressure values ​​when the engine is in stable operation, and determines the current clogging level of the filter component based on the difference between the collected negative pressure value and the reference value. The clogging level includes at least mild clogging, moderate clogging and severe clogging. The reference value is the negative pressure value recorded after the last cleaning was completed and left to stand for a set time. The controller (12) updates the value based on the current actual negative pressure value after each cleaning. S2. The controller (12) matches the operating intensity and reference operating time of the fan (10) corresponding to the blockage level determined in S1, and starts the fan (10) to purge and clean the air filter. S3. During the operation of the fan (10), the controller (12) continuously collects the negative pressure value in real time through the negative pressure sensor (13). The controller (12) takes the absolute value of the collected negative pressure value as the current pressure difference, and determines whether to terminate the operation of the fan (10) in advance based on the rate of decrease of the pressure difference and the deviation between the current pressure difference and the reference pressure difference value. If the early termination condition is not met, the fan (10) continues to run until the reference running time is exhausted and then stops. The reference pressure difference value is the clean reference pressure difference value initially calibrated by the system.

7. The self-cleaning method according to claim 6, characterized in that, In step S1: The controller (12) simultaneously collects the engine speed signal and the speed change per unit time. When the speed is 70%-90% of the rated speed and the fluctuation of the engine speed within any 3-second window is less than 30 revolutions per second, the controller (12) determines that it is a stable operating condition and executes the subsequent steps. The controller (12) has three preset differential pressure boundary values ​​A, B and C, where A < B < C. The difference between the collected negative pressure value and the reference value is calculated as ΔS = Pc. Pb, where Pc is the real-time negative pressure value collected by the negative pressure sensor (13) at the current moment, and Pb is the baseline value recorded after standing for 5 seconds after the last cleaning is completed; the blockage level is determined according to the range in which the difference ΔS falls: the difference between A and B is a light blockage, the difference between B and C is a moderate blockage, and the difference exceeding C is a severe blockage. When the difference between the collected negative pressure value and the reference value ΔS has not yet reached the boundary value A, the controller (12) calculates the rate of increase of the pressure difference, that is, the rate of increase of the negative pressure value Pc relative to the reference value Pb. If the rate exceeds 0.15 kPa / s, the controller (12) marks it as a preparatory cleaning state in advance.

8. The self-cleaning method according to claim 7, characterized in that, In step S2: The controller (12) defines the current differential pressure deviation as E(t) = P(t). Pb, where P(t) is the real-time negative pressure value collected by the negative pressure sensor (13) at the current time t, and Pb is the baseline value recorded after the last cleaning; the first-order rate of change of pressure difference R(t) = dE(t) / dt is defined as the rate of decrease of pressure difference, in kPa / s; the second-order rate of change of pressure difference A(t) = d²E(t) / dt² is defined as the acceleration of the rate of decrease of pressure difference, in kPa / s², and the controller (12) determines the starting duty cycle D0 of the fan (10) according to the blockage level determined by S1: When the congestion level is light, D0 = 60%; When the congestion level is moderate, D0 = 80%; When the congestion level is severe, D0 = 100%; After the fan (10) starts, the controller (12) performs periodic sampling and calculation. In each period, the controller (12) updates the duty cycle D: When R(t) < 0.02 kPa / s and A(t) ≥ 0 kPa / s², it indicates that the current pressure difference decreases very slowly or even stagnates, and there is no accelerating downward trend. The cleaning efficiency is insufficient, and the controller (12) executes the upward adjustment strategy: D(t+1) = min(D(t) +5%, 100%), where D(t+1) is the duty cycle of the next adjustment cycle and D(t) is the duty cycle of the current adjustment cycle. When R(t) > 0.06 kPa / s and A(t) ≤ 0 kPa / s², the controller (12) executes the down-adjustment strategy: D(t+1) = max(D(t)). 3%, 50%); When R(t) > 0.06 kPa / s and A(t) > 0 kPa / s², the controller (12) executes a fast down-adjustment strategy: D(t+1) = max(D(t)). 5%, 50%); When 0.02 kPa / s ≤ R(t) ≤ 0.06 kPa / s, the controller (12) maintains the current duty cycle unchanged, that is, D(t+1) = D(t); In each formula, the min and max functions are used to limit the upper and lower boundary values ​​of the duty cycle, respectively, with the upper limit of the duty cycle being 100% and the lower limit being 50%.

9. The self-cleaning method according to claim 8, characterized in that, In step S3: The negative pressure sensor (13) continuously collects the negative pressure value P(t) in real time during the operation of the fan (10) and sends it to the controller (12). The controller (12) takes the absolute value of the negative pressure value as the current pressure difference, compares the current pressure difference with the reference pressure difference value, and calculates the deviation ΔPa = |P(t)|. Pr, where Pr is the reference differential pressure value in S1; The conditions for early termination of the operation of the fan (10) are: the deviation ΔPa has dropped to within ±5% of Pr, and the rate of pressure drop R(t) is less than 0.08 kPa / s, where R(t) = dP(t) / dt. When both conditions are met, the controller (12) stops the operation of the fan (10). After each cleaning is completed, the controller (12) records the current actual negative pressure value and updates it to the reference value used in the next S1 step, that is, updates Pb; if this cleaning is the first run or the reference value has not been initialized, the controller (12) uses the average value of 10 consecutive negative pressure values ​​collected after the engine is first started and running stably as the initial reference value; after the reference value is updated, the controller (12) stores the highest negative pressure value, the final negative pressure value and the actual running time recorded during this cleaning process in the internal memory for subsequent reference value correction.

10. The self-cleaning method according to any one of claims 6-9, characterized in that, It also includes setting a forced start switch (14). After the forced start switch is turned on, the fan (10) starts directly to clean the filter components.

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