A driving and parking dual-mode positive pressure dustproof control system for a trailer house car

Abstract

The application discloses a kind of for towing motor home's driving and parking dual-mode positive pressure dustproof control system. Including central control module and with its electrical connection's differential pressure sensor, dual-power fan, hierarchical pressure relief, air intake filter, trigger module;Central control module switches between parking and driving mode according to working condition signal, respectively control cabin maintains 5~15Pa, 50~200Pa Positive pressure interval, cooperate with dual-fan independent regulation and control, hierarchical pressure relief realizes accurate stable control.The application can simultaneously adapt parking and driving two scenes, give consideration to low energy consumption quiet comfort and efficient dustproof exhaust protection, improve the cabin environment quality and operation reliability of whole scene use of towing motor home.

Description

Technical Field

[0001] This invention relates to the field of RV sealing and dust prevention technology, specifically to a dual-mode positive pressure dust prevention control system for towed RVs, which is used for both driving and parking. Background Technology

[0002] As a type of mobile living space, towed caravans are mainly used in two scenarios: long-term camping and short-distance road travel. To ensure air quality inside the vehicle and prevent the infiltration of external dust and vehicle exhaust, some caravans are equipped with positive pressure dustproof devices. These devices supply filtered air into the vehicle, creating an air curtain barrier with a slightly higher air pressure inside than outside.

[0003] Currently, most existing positive pressure dust suppression devices for trailer caravans employ a single differential pressure threshold control scheme, which involves setting a fixed target positive pressure value for maintenance. However, this single-threshold scheme has significant drawbacks in practical applications.

[0004] On the one hand, if the differential pressure threshold of the device is set to a low value (e.g., around 10 Pa), it can achieve low-energy consumption and low-noise operation when parked, providing a relatively quiet resting environment for the occupants. However, when the vehicle is in motion, external airflow, crosswinds, and other disturbances will quickly offset this small positive pressure difference, causing the positive pressure barrier inside the cabin to fail. External dust and vehicle exhaust can easily flow back into the vehicle through gaps in the body, failing to meet the protection requirements under driving conditions.

[0005] On the other hand, if the differential pressure threshold of the device is set to a higher value (e.g., around 150 Pa), the dustproof and backflow prevention effects during driving can be guaranteed. However, during long-term parking, a high threshold means that the fan needs to operate at high power continuously, which not only leads to high energy consumption and high operating noise (often exceeding 50 dB), affecting living comfort, but also the excessively high cabin pressure can easily cause pressure on the eardrums, making it difficult to meet the core requirements of quietness and comfort when parked.

[0006] Therefore, existing positive pressure dustproof devices that use a single differential pressure threshold cannot meet the differentiated needs of towed caravans under the two main operating conditions of parking and driving, resulting in a technical problem of conflict between protective effect and living comfort. Summary of the Invention

[0007] Purpose of the Invention: To overcome the shortcomings of existing technologies, this invention provides a dual-mode positive pressure dustproof control system for towed caravans, which identifies the parking or driving conditions of the caravan in real time through a trigger module. The central control module automatically switches between parking and driving modes based on the identification results. Target control thresholds are set at a low pressure difference range of 5-15Pa and a high pressure difference range of 50-200Pa, respectively. Combined with a dual-power fan module and a graded pressure relief module, the pressure inside the cabin is precisely regulated. This achieves low energy consumption and quiet operation when parked, and forms a stable and efficient air curtain barrier to resist sand and exhaust backflow when driving. Furthermore, with the addition of pressure difference gradual control, fan overheat protection, underpressure alarm, and a double-layer filtration structure, this invention effectively solves the technical problem that existing single pressure difference threshold solutions cannot simultaneously address parking comfort and driving protection.

[0008] A dual-mode positive pressure dust prevention control system for towed caravans includes: a central control module; a differential pressure sensing module, a dual-power fan module, a graded pressure relief module, an air intake filter module, and a trigger module electrically connected to the central control module; Wherein: the differential pressure sensing module has a range of 0~300Pa and an accuracy of ±1Pa, and is used to detect the pressure difference between the RV cabin and the external environment in real time and send a pressure signal to the central control module; The triggering module is used to generate a condition signal indicating whether the RV is in a parked or driving state and send it to the central control module; The dual-power fan module is used to supply external air filtered by the air intake filter module into the cabin to increase the positive pressure inside the cabin. The graded pressure relief module is used to release air inside the cabin to reduce the pressure and ensure the stability of the pressure range when the pressure inside the cabin exceeds the upper limit threshold of the corresponding mode. The central control module switches between parking mode and driving mode according to the operating condition signal, and uses different target pressure difference ranges to precisely control the dual-power fan module and the staged pressure relief module so that the pressure inside the cabin is stably maintained within the target positive pressure range of the corresponding mode. Furthermore, in parking mode, the central control module maintains the cabin pressure within a first positive pressure range of 5-15 Pa; in driving mode, the central control module maintains the cabin pressure within a second positive pressure range of 50-200 Pa, which is higher than the first positive pressure range. This fundamentally solves the core pain point of existing single differential pressure threshold solutions that cannot simultaneously address parking comfort and driving safety. A single system is suitable for both parking / camping and road driving scenarios. The fully closed-loop architecture enables fully automatic and precise control of the cabin positive pressure without frequent manual intervention, significantly improving ease of use and driving safety. The high-precision differential pressure sensing module ensures accurate detection in micro-differential pressure scenarios, providing reliable data support for dual-mode precise pressure control and avoiding problems such as positive pressure barrier failure and cabin pressure exceeding limits causing discomfort due to differential pressure detection deviations.

[0009] The system described in this invention includes a dual-power fan module comprising a low-pressure fan and a medium-pressure fan. The low-pressure fan is adapted for positive pressure regulation in parking mode, while the medium-pressure fan is adapted for positive pressure regulation in driving mode. Both fans are equipped with independent speed control modules, and their start / stop and speed are independently controlled by the central control module to achieve precise control of cabin pressure. The dual fans are matched to the power requirements of the two operating conditions. When parked, the low-pressure fan operates at low power, significantly reducing energy consumption and operating noise, and improving the living comfort while parked. When driving, the medium-pressure fan outputs full power, which can quickly establish and stably maintain a high pressure differential positive pressure barrier to resist positive pressure failure caused by external airflow and crosswind disturbances during driving. Independent speed regulation and independent start / stop control achieve stepless and precise control of cabin pressure, solving the industry pain points of insufficient control accuracy and large pressure fluctuations when switching between high and low power of a single fan, and significantly improving the stability of cabin pressure.

[0010] The system described in this invention includes a graded pressure relief module comprising a low-pressure relief valve and a medium-pressure relief valve, corresponding to pressure relief control in parking and driving modes, respectively. Both the low-pressure and medium-pressure relief valves are equipped with sealing rings to ensure the overall airtightness of the device. The graded pressure relief design enables independent control of the pressure upper limit under both operating conditions. When parked, the low-pressure relief valve precisely controls the upper limit of the low-pressure range, preventing discomfort caused by excessive pressure on the eardrums. When driving, the medium-pressure relief valve controls the upper limit of the high-pressure range, preventing excessive pressure within the cabin from damaging the cabin's sealing structure. The sealing ring design ensures the overall airtightness of the cabin when the pressure relief valve is closed, preventing leakage in non-relief states that could lead to positive pressure failure, significantly improving the reliability of the system's dust protection.

[0011] The system described in this invention features a low-pressure relief valve that automatically opens to release pressure when the cabin pressure reaches the upper limit threshold of 15 Pa in parking mode, and automatically closes when the pressure drops below 15 Pa. Similarly, the medium-pressure relief valve automatically opens to release pressure when the cabin pressure reaches the upper limit threshold of 200 Pa in driving mode, and automatically closes when the pressure drops below 200 Pa. Simultaneously, the central control module controls the medium-pressure fan to shut down while simultaneously controlling the opening of the medium-pressure relief valve. This precise opening and closing threshold design achieves passive pressure stabilization within the cabin, forming a dual guarantee with the active pressure control of the central control module. This ensures that the cabin pressure remains stable within the target range for the corresponding mode. The coordinated control of the medium-pressure relief valve and the medium-pressure fan avoids ineffective energy consumption caused by continuous high-power operation of the fan when the relief valve is open, reduces mechanical wear from ineffective fan operation, extends equipment lifespan, and quickly reduces cabin pressure, preventing continuous pressure exceeding limits.

[0012] The system described in this invention comprises a trigger module consisting of a vehicle speed sensor and a manual switch. The central control module determines the RV's operating condition based on the vehicle speed signal collected by the vehicle speed sensor or the manual switching command signal from the manual switch, and generates a corresponding operating condition signal to execute mode switching. The vehicle speed sensor enables fully automatic identification and mode switching of driving or parking conditions without manual operation, avoiding safety hazards caused by manual operation during driving and significantly improving ease of use and driving safety. The manual switch retains the highest level of human intervention, enabling mode switching in special scenarios such as strong sandstorms or driving on special road conditions while parked, greatly improving the system's scenario adaptability and usage flexibility.

[0013] The system described in this invention automatically triggers the driving mode when the vehicle speed sensor detects a speed ≥ 40 km / h; and triggers the parking mode when the vehicle speed is < 30 km / h or when the central control module receives a parking command signal from the manual switching switch. This dual-trigger logic ensures accurate mode switching. The tiered speed threshold and buffer zone design avoids frequent mode switching during vehicle acceleration / deceleration, idling, and traffic jams, significantly improving system stability. The speed trigger thresholds are precisely adapted to the driving characteristics of the towed caravan. When the vehicle speed is ≥ 40 km / h, external airflow disturbances are significantly enhanced, prompting timely switching to the high-pressure differential mode to ensure protective effectiveness; at low speeds, a low-pressure differential mode is switched to prioritize cabin comfort. The manual command priority mechanism ensures controllability in special scenarios, enhancing system safety redundancy and scenario adaptability.

[0014] The system described in this invention includes a transition control logic within the central control module. During the switching between parking and driving modes, when the vehicle speed is in the critical range of 30-40 km / h, a gradual control strategy is used to progressively change the cabin pressure from 5-15 Pa to 50-200 Pa, gradually adjusting the target cabin pressure value to avoid sudden pressure changes that could cause discomfort. This completely avoids discomfort such as eardrum pressure and tinnitus caused by sudden pressure changes during mode switching, significantly improving the comfort of passengers. The transition control in the critical range fills the pressure control gap during mode switching, avoiding pressure fluctuations and control logic disorder at critical vehicle speeds, and improving the continuity and stability of system pressure control.

[0015] The system described in this invention features a dual-layer air intake filtration module, comprising a primary filter layer and a secondary filter layer arranged sequentially along the airflow direction. The primary filter layer intercepts large particles of dust and insects, while the secondary filter layer intercepts fine particulate matter. Furthermore, the air intake end of the air intake filtration module is equipped with a unidirectional flow-guiding structure to prevent external airflow and exhaust fumes from flowing back into the RV cabin. This dual-layer, graded filtration achieves comprehensive air purification. The primary filter layer intercepts large particulate pollutants such as dust and insects while protecting the secondary filter layer and extending its overall lifespan. The secondary filter layer intercepts fine particulate matter such as PM2.5, comprehensively improving the air quality inside the cabin. The unidirectional flow-guiding structure completely prevents high-pressure external airflow and vehicle exhaust fumes from flowing back into the cabin through the air intake channel during driving, avoiding reverse failure of the positive pressure barrier and further enhancing the system's dust and exhaust gas protection effects.

[0016] The system described in this invention includes a central control module equipped with a fan overheat protection function. When the dual-power fan module operates continuously for more than a preset duration of 8 hours, the central control module automatically switches to a low-pressure fan low-speed operation state for 30 minutes, after which it returns to the original operating mode. This switching of operating states extends the service life of the dual-power fan module. The protection state uses low-pressure fan low-speed operation, which, while achieving fan cooling, maintains the basic positive pressure inside the cabin, preventing interruption of dust protection and ensuring the continuity of system protection. The preset duration and protection duration are precisely adapted to the core usage scenarios of long-term parking and camping and long-distance driving for towed caravans, achieving fully automatic overheat protection without manual intervention and improving the reliability of the equipment for outdoor use. The system described in this invention includes a central control module equipped with an underpressure alarm function. When the cabin pressure in driving mode remains below the lower limit of the second positive pressure range of 50 Pa for a preset time of more than 10 minutes, the central control module automatically outputs a fault warning signal, indicating that there is a sealing failure in the RV cabin or a malfunction in the dual-power fan module. The underpressure alarm function can promptly identify abnormal problems such as cabin sealing failure and fan malfunction, preventing the positive pressure barrier from failing undetected during driving, which could lead to sand and exhaust gas seeping into the cabin, thus significantly improving the reliability and safety of the system's protection. The device is also equipped with a high-airtightness sealing strip for trailer caravans. The high-airtightness sealing strip is compatible with the doors, windows, cabin doors and various pipe interfaces of the trailer caravan. The sealing strip is made of weather-resistant material to ensure the stability of the positive pressure environment inside the cabin and is suitable for use in complex outdoor working conditions.

[0017] As can be seen from the above technical solution, the present invention has the following beneficial effects: This invention discloses a dual-mode positive pressure dust control system for towed caravans, which identifies and accurately determines the caravan's parking and driving conditions through a trigger module. The central control module automatically switches between parking and driving modes and matches different target differential pressure control ranges for the two conditions. Based on real-time differential pressure data from a high-precision differential pressure sensor module, and through the independent start / stop and stepless speed regulation of a dual-power fan module and the graded opening / closing and linkage control of a graded pressure relief module, a fully closed-loop precise control system for positive pressure inside the cabin is formed. This system ensures that the cabin pressure is stably maintained in the first positive pressure range of 5-15 Pa in parking mode and stably maintained in the range of 50-200 Pa in driving mode. The second positive pressure zone; simultaneously, through differential pressure gradual transition control during mode switching, dual-layer graded filtration and unidirectional anti-backflow structure at the air intake end, fan overheat protection mechanism, under-pressure alarm function under driving conditions, and synergistic optimization of matching weather-resistant and airtight sealing strips for trailer caravans, the same system simultaneously addresses the core requirements of low energy consumption, low noise, and high living comfort under parking conditions, and the high protection requirements of resisting airflow disturbance and preventing sand and dust exhaust backflow under driving conditions. It fundamentally solves the technical problem of the contradiction between the protective effect and living comfort of existing single differential pressure threshold positive pressure dustproof devices, and greatly improves the cabin environment quality, ease of use, and equipment operation reliability of trailer caravans in all scenarios. Attached Figure Description

[0018] Figure 1 This is a block diagram of the overall structure of a dual-mode positive pressure dustproof control system for towed caravans according to the present invention. Figure 2 This is a schematic diagram of the dual-power fan module structure in a dual-mode positive pressure dustproof control system for towed caravans according to the present invention. Figure 3This is a schematic diagram of the graded pressure relief module structure in a dual-mode positive pressure dust prevention control system for towed caravans according to the present invention. Figure 4 This is a schematic diagram of the air intake filter module in a dual-mode positive pressure dustproof control system for towed caravans according to the present invention. Figure 5 This invention provides an installation layout diagram for a dual-mode positive pressure dustproof control system for towed caravans. Figure 6 This invention provides a dual-mode control logic flowchart for a dual-mode positive pressure dustproof control system for towed caravans. Detailed Implementation

[0019] Example 1 This embodiment provides a dual-mode positive pressure dustproof control system for towed caravans, which can be adapted to the two core usage scenarios of towed caravans: parking and camping, and road driving. It also takes into account the low energy consumption and high comfort requirements of parking conditions and the high protection requirements of driving conditions.

[0020] As shown in the overall system structure diagram in Figure 1, the control system described in this embodiment includes a central control module, and electrically connected components such as a differential pressure sensing module, a dual-power fan module, a staged pressure relief module, an air intake filter module, and a trigger module. It is also equipped with a high-airtightness sealing strip specifically designed for trailer caravans. The signal output terminal of the differential pressure sensing module is connected to the analog input interface of the central control module. The signal output terminal of the trigger module is connected to the digital input interface and the CAN bus interface of the central control module. The controlled terminals of the dual-power fan module and the staged pressure relief module are both connected to the drive output interface of the central control module. The air intake filter module is sealed and connected to the air intake end of the dual-power fan module through a ventilation duct.

[0021] The following, with reference to Figures 2 to 5, provides a detailed description of the specific structure, installation layout, and parameter settings of each module: The core of the central control module is a 32-bit automotive-grade MCU controller, with built-in mode switching control logic, differential pressure gradual transition control logic, fan overheat protection logic, and undervoltage alarm logic. It is equipped with multiple analog input interfaces, digital input / output interfaces, PWM drive interfaces, and CAN bus communication interfaces. As shown in Figure 5, the RV installation layout, the central control module is integrated into the control panel area inside the RV. A matching manual switch is integrated into the control panel for easy operation and status monitoring. All module connection cables are shielded and concealed along the interior trim of the RV cabin, avoiding exposed wiring and improving protection and aesthetics.

[0022] As shown in Figure 1, the differential pressure sensing module uses a micro differential pressure sensor with a range of 0~300Pa and a detection accuracy of ±1Pa. Its two detection terminals are connected to the interior environment of the RV cabin and the external atmospheric environment, respectively, to detect the pressure difference between the cabin and the outside in real time, and convert the differential pressure signal into a standard electrical signal for transmission to the central control module. As shown in Figure 5, the differential pressure sensing module is installed at the top of the middle of the RV cabin, away from airflow disturbance areas such as the fan outlet, doors, and windows, to avoid detection deviations caused by direct airflow and ensure detection accuracy in micro-pressure scenarios.

[0023] The trigger module, as shown in Figures 1 and 5, is a combination of a vehicle speed sensor and a manual switch, enabling dual identification of operating conditions and mode switching. The vehicle speed sensor is installed at the axle detection end of the towing interface of the caravan to collect the real-time driving speed of the caravan. The speed signal is transmitted to the central control module via the CAN bus. The manual switch is a self-locking push-button switch with two positions: parking mode and driving mode. Its signal output is electrically connected to the digital input interface of the central control module. The manual switching command has higher priority than the automatic vehicle speed triggering logic, which can handle mode switching needs in special scenarios.

[0024] The dual-power fan module is shown in the structural diagram of Figure 2 and the installation layout in Figure 5. The dual-power fan module is bolted to the inner side of the front wall of the RV cabin using a fixed bracket. The entire module is encapsulated in an integrated sealed shell, including a low-pressure fan, a medium-pressure fan, two independent PWM speed control modules, an air inlet interface, and an air outlet interface. The low-pressure fan is a silent centrifugal fan with a rated power of 8W and a rated air pressure of 0~30Pa, suitable for the low pressure differential adjustment requirements in parking mode. The medium-pressure fan is a high-pressure centrifugal fan with a rated power of 50W and a rated air pressure of 0~300Pa, suitable for the high pressure differential adjustment requirements in driving mode. Both fans share the same air inlet interface, which connects to the air outlet of the air intake filter module via a ventilation duct. A weather-resistant rubber sealing ring is installed at the connection point. Both fans share the same air outlet interface, which directly connects to the RV cabin environment. Each fan is equipped with an independent PWM speed control module. The control terminal of the speed control module is electrically connected to the PWM output interface of the central control module. The central control module can independently control the start, stop and speed of the two fans, realizing stepless and precise control of the cabin pressure.

[0025] As shown in Figure 4, the intake filter module is installed at the front end of the dual-power fan module's air inlet. It is sealed and connected to the air inlet interface of the dual-power fan module via a ventilation duct, and is a cylindrical sealed housing structure. Inside the housing, along the airflow direction, a unidirectional flow guide, a pre-filter layer, and a medium-efficiency filter layer are sequentially arranged. The unidirectional flow guide is a one-way check valve structure, located at the air inlet end of the filter housing, allowing only outside air to flow into the housing from outside, preventing backflow of high-pressure airflow and vehicle exhaust through the intake channel. The pre-filter layer uses G4-grade pre-filter cotton to intercept large particles of dust, insects, fallen leaves, and other pollutants, while protecting the subsequent medium-efficiency filter layer. The medium-efficiency filter layer uses F8-grade medium-efficiency filter material to intercept fine particulate matter such as PM2.5, achieving dual purification of the intake air. The air outlet end of the filter housing is equipped with a mating interface with a silicone rubber sealing ring, sealingly connecting to the ventilation duct to prevent air leakage at the interface.

[0026] The tiered pressure relief module is shown in the structural diagram in Figure 3 and the installation layout in Figure 5. Two sets of tiered pressure relief modules are installed on the top left and right sides of the RV cabin using bolts via mounting bases. Rain covers are provided at the installation locations to prevent rainwater infiltration. Each tiered pressure relief module integrates a low-pressure relief valve and a medium-pressure relief valve. Both valves are spring-loaded one-way valves, with pressure relief from inside the cabin to the outside. Silicone rubber sealing rings are installed between the valve core and the valve seat to ensure airtightness when closed. Specifically, the spring preload of the low-pressure relief valve is set as follows: when the cabin pressure reaches 15 Pa, the valve core automatically opens to relieve pressure against the spring force; it automatically closes when the pressure drops below 15 Pa, adapting to the pressure limit control in parking mode. The spring preload of the medium-pressure relief valve is set as follows: when the cabin pressure reaches 200 Pa, the valve core automatically opens to relieve pressure against the spring force; it automatically closes when the pressure drops below 200 Pa, adapting to the pressure limit control in driving mode. Meanwhile, the opening and closing status feedback terminal of the medium-pressure relief valve is electrically connected to the central control module. When the medium-pressure relief valve is opened, the central control module synchronously controls the medium-pressure fan to stop.

[0027] The system is equipped with high-airtightness sealing strips made of EPDM weather-resistant rubber. These strips are suitable for all gaps in the cabin, including doors, windows, storage compartment doors, air conditioning pipes, and water and electricity interfaces. They are used to improve the overall airtightness of the cabin, ensure the stable establishment of a positive pressure environment inside the cabin, and can be used in complex outdoor conditions ranging from -40℃ to 80℃.

[0028] The complete working process of the control system described in this embodiment will be explained in detail below with reference to the dual-mode control logic flowchart in Figure 6: After the initial self-test device is powered on, the central control module first executes the initial self-test program to perform a full self-test on the differential pressure sensing module, dual-power fan module, staged pressure relief valve status sensor, vehicle speed sensor, and manual switch. If a fault is found during the self-test, the central control module immediately outputs a fault warning signal. If no abnormality is found during the self-test, the system enters a continuous monitoring standby state.

[0029] The working condition recognition and pattern triggering system achieves dual recognition of working conditions and pattern triggering through a triggering module. The specific logic is as follows: Automatic triggering logic: The central control module receives real-time vehicle speed signals collected by the vehicle speed sensor. When the vehicle speed is detected to be ≥40km / h, the driving mode is automatically triggered; when the vehicle speed is detected to be <30km / h, the parking mode is automatically triggered; when the vehicle speed is in the critical range of 30~40km / h, the transition control logic is activated. Manual triggering logic: Regardless of the current vehicle speed range, when the central control module receives a mode switching command from the manual switch, it immediately executes the corresponding mode switch. The manual command has higher priority than the automatic speed triggering logic.

[0030] When the system triggers parking mode, the central control module sets the target pressure difference range to the first positive pressure range of 5-15 Pa, and simultaneously shuts down the medium-pressure fan, starting only the low-pressure fan. The pressure difference sensing module collects the pressure difference signal between the inside and outside of the cabin in real time and feeds it back to the central control module. Based on the difference between the real-time pressure difference and the target range, the central control module adjusts the speed of the low-pressure fan in real time through the PWM speed control module: when the pressure difference inside the cabin is lower than 5 Pa, the speed of the low-pressure fan is increased to increase the air intake and increase the pressure inside the cabin; when the pressure difference inside the cabin is within the range of 5-15 Pa, the current speed of the low-pressure fan is maintained to stabilize the pressure inside the cabin; when the pressure difference inside the cabin reaches the upper limit threshold of 15 Pa, the low-pressure relief valve automatically opens to release pressure, and automatically closes after the pressure drops below 15 Pa. This, together with the active speed adjustment of the central control module, forms a dual stabilization control to ensure that the pressure inside the cabin is stably maintained within the target range. In this mode, the low-pressure fan operates quietly with low power, and the operating noise is ≤30dB, achieving low energy consumption and high comfort for parking dust protection.

[0031] When the system triggers driving mode, the central control module sets the target pressure difference range to the second positive pressure range of 50~200Pa, and at the same time shuts down the low-pressure fan and starts the medium-pressure fan only. The differential pressure sensing module collects the pressure difference signal between the inside and outside of the cabin in real time and feeds it back to the central control module. Based on the difference between the real-time pressure difference and the target range, the central control module adjusts the speed of the medium-pressure fan in real time through the PWM speed control module: when the pressure difference inside the cabin is lower than 50Pa, the speed of the medium-pressure fan is increased to quickly increase the air intake and establish a stable positive pressure barrier; when the pressure difference inside the cabin is in the range of 50~200Pa, the current speed of the medium-pressure fan is maintained to stabilize the cabin pressure and resist the disturbance of external airflow and crosswind during vehicle operation, preventing sand and exhaust gas backflow; when the pressure difference inside the cabin reaches the upper limit threshold of 200Pa, the medium-pressure relief valve automatically opens to release pressure, and at the same time, the central control module synchronously controls the medium-pressure fan to stop, quickly reducing the cabin pressure to below 200Pa. After that, the medium-pressure relief valve automatically closes, and the medium-pressure fan resumes normal operation, avoiding damage to the cabin sealing structure due to excessive cabin pressure and reducing ineffective energy consumption.

[0032] When the vehicle speed is in the critical range of 30-40 km / h, and the system switches between parking and driving modes, the central control module activates a gradual control strategy. Instead of directly switching the target pressure differential range, it gradually increases the target cabin pressure value over a 45-second transition period, from a first positive pressure range of 5-15 Pa to a second positive pressure range of 50-200 Pa, or vice versa. During this process, the central control module simultaneously adjusts the speed of the corresponding fan to achieve a smooth pressure transition, avoiding discomfort such as eardrum pressure and tinnitus caused by sudden pressure changes.

[0033] Working process of auxiliary protection and alarm functions Fan overheat protection function: The central control module monitors the continuous running time of the dual-power fan module in real time. When the continuous running time of the fan exceeds the preset 8 hours, the overheat protection program is automatically activated. The control device switches to the low-pressure fan low-speed operation state for 30 minutes to achieve fan heat dissipation and cooling while maintaining the basic positive pressure in the chamber to ensure uninterrupted dust protection. After the 30-minute protection period ends, the system automatically returns to the original working mode to extend the service life of the fan. Low pressure alarm function: In driving mode, the central control module monitors the cabin pressure difference in real time. When the cabin pressure is detected to be continuously lower than the lower limit of the second positive pressure range of 50Pa for more than 10 minutes, the central control module determines that there is an abnormality in the system and automatically outputs a fault prompt signal. The user is notified through the display screen and buzzer of the RV control panel that there is a sealing failure in the RV cabin or a malfunction in the dual-power fan module, so as to avoid sand and exhaust gas seepage caused by the failure of the positive pressure barrier.

[0034] This embodiment, through the above structure and control logic, simultaneously addresses the core requirements of low energy consumption, low noise, and high living comfort under parking conditions for towed caravans, as well as the high protection requirements of resisting airflow disturbances and preventing dust and exhaust gas backflow under driving conditions within the same system. It fundamentally solves the technical problem of the contradiction between the protective effect and living comfort of existing single differential pressure threshold positive pressure dustproof devices.

[0035] The above embodiments are exemplary and are intended to illustrate the technical concept and features of the present invention, so that those skilled in the art can understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All changes or modifications made according to the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A dual-mode positive pressure dust prevention control system for towed caravans, including driving and parking modes. Its features are, Includes: a central control module; a differential pressure sensing module, a dual-power fan module, a staged pressure relief module, an air intake filter module, and a trigger module electrically connected to the central control module; Wherein: the differential pressure sensing module is used to detect the pressure difference between the RV cabin and the external environment in real time and send a pressure signal to the central control module; The triggering module is used to generate a condition signal indicating whether the RV is in a parked or driving state and send it to the central control module; The dual-power fan module is used to supply external air filtered by the air intake filter module into the cabin to increase the positive pressure inside the cabin. The graded pressure relief module is used to release air inside the cabin to reduce the pressure and ensure the stability of the pressure range when the pressure inside the cabin exceeds the upper limit threshold of the corresponding mode. The central control module switches between parking mode and driving mode according to the operating condition signal, and uses different target pressure difference ranges to precisely control the dual-power fan module and the staged pressure relief module so that the pressure inside the cabin is stably maintained within the target positive pressure range of the corresponding mode. In parking mode, the central control module controls the cabin pressure to be maintained in a first positive pressure range of 5~15Pa; in driving mode, the central control module controls the cabin pressure to be maintained in a second positive pressure range of 50~200Pa, which is higher than the first positive pressure range.

2. The dual-mode positive pressure dustproof control system for towed caravans according to claim 1, characterized in that, The dual-power fan module includes a low-pressure fan and a medium-pressure fan. The low-pressure fan is adapted to positive pressure regulation in parking mode, and the medium-pressure fan is adapted to positive pressure regulation in driving mode. Both are equipped with independent speed control modules, and the start, stop and speed are independently controlled by the central control module to achieve precise control of cabin pressure.

3. A dual-mode positive pressure dustproof control system for driving and parking of a towed caravan according to claim 2, characterized in that, The graded pressure relief module includes a low-pressure relief valve and a medium-pressure relief valve, which correspond to the pressure relief control of the parking mode and the driving mode, respectively. Both the low-pressure relief valve and the medium-pressure relief valve are equipped with sealing rings to ensure the overall airtightness of the device.

4. A dual-mode positive pressure dustproof control system for driving and parking of a towed caravan according to claim 3, characterized in that, The low-pressure relief valve automatically opens to relieve pressure when the pressure inside the cabin reaches the upper limit threshold of 15Pa in the parking mode, and automatically closes when the pressure drops to below 15Pa. The medium-pressure relief valve automatically opens to relieve pressure when the pressure inside the cabin reaches the upper limit threshold of 200Pa in the driving mode, and automatically closes when the pressure drops to below 200Pa. At the same time as the central control module controls the opening of the medium-pressure relief valve, it simultaneously controls the medium-pressure fan to stop.

5. A dual-mode positive pressure dustproof control system for driving and parking of a towed caravan according to claim 1, characterized in that, The triggering module is a combination of a vehicle speed sensor and a manual switch. The central control module determines the RV's operating condition based on the vehicle speed signal collected by the vehicle speed sensor or the manual switching command signal from the manual switch, and generates a corresponding operating condition signal to perform mode switching.

6. A dual-mode positive pressure dustproof control system for driving and parking of a towed caravan according to claim 5, characterized in that, When the vehicle speed sensor detects a vehicle speed of ≥40km / h, the central control module automatically triggers the driving mode. When the vehicle speed is less than 30 km / h or the central control module receives a parking command signal from the manual switch, the parking mode is triggered. The dual trigger logic ensures the accuracy of mode switching.

7. A dual-mode positive pressure dustproof control system for towed caravans according to claim 6, characterized in that, The central control module is equipped with a transition control logic. During the switching between parking mode and driving mode, when the vehicle speed is in the critical range of 30~40km / h, the cabin pressure is gradually changed from 5~15Pa to 50~200Pa through a gradual control strategy, so as to gradually adjust the target value of cabin pressure and avoid sudden pressure changes that may cause discomfort to the human body.

8. A dual-mode positive pressure dustproof control system for driving and parking of a towed caravan according to claim 1, characterized in that, The air intake filter module has a dual-layer filter structure, including a primary filter layer and a secondary filter layer arranged sequentially along the airflow direction. The primary filter layer is used to intercept large particles of sand and dust and insects, while the secondary filter layer is used to intercept fine particles. The air intake end of the air intake filter module is equipped with a one-way flow guide structure to prevent external airflow and exhaust gas from flowing back into the RV cabin.

9. A dual-mode positive pressure dustproof control system for towed caravans according to claim 1, characterized in that, The central control module is also equipped with a fan overheat protection function. When the dual-power fan module runs continuously for more than 8 hours, the central control module automatically switches to the low-speed operation of the low-pressure fan for 30 minutes, and then returns to the original working mode. By switching the operating state, the service life of the dual-power fan module is extended.

10. A dual-mode positive pressure dustproof control system for driving and parking of a towed caravan according to claim 1, characterized in that, The central control module is also equipped with an underpressure alarm function. When the cabin pressure in driving mode is continuously lower than the lower limit of the second positive pressure range of 50Pa for more than 10 minutes, the central control module automatically outputs a fault prompt signal to indicate that there is a sealing fault in the RV cabin or that the dual-power fan module has an operational fault. The device is also equipped with a high-airtightness sealing strip for trailer caravans. The high-airtightness sealing strip is compatible with the doors, windows, cabin doors and various pipe interfaces of the trailer caravan. The sealing strip is made of weather-resistant material to ensure the stability of the positive pressure environment inside the cabin and is suitable for use in complex outdoor working conditions.

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