Air return device, air return system and air return method

Abstract

The present invention relates to the field of engine thermal management technology, and specifically to a return air device, a return air system and a return air method. The return air device is provided with a guide module, a connection module and a hinge module. The guide module can be provided between the cab floor and the engine cooling module. The connection module is connected to one end of the guide module and can be connected to the cab floor. The return air device is provided with a hinge module so that the guide module can rotate relative to the engine cooling module. The guide module accelerates the cooling efficiency of the cooling module by rotating away from the engine, thereby making the return air system more suitable for high temperature working conditions in summer. The guide module reduces the cooling efficiency of the cooling module by rotating toward the engine, making the return air system more suitable for low temperature working conditions of the engine, which helps to improve the combustion efficiency and power performance of the engine under different environments.

Description

Technical Field

[0001] The present invention relates to the technical field of engine thermal management, and in particular to an air return device, an air return system and an air return method. Background Art

[0002] The engine cooling system removes heat absorbed by high-temperature engine parts during operation, keeping them within a normal operating temperature range. The engine cooling system protects the engine from both overheating and overcooling. Both overheating and overcooling can disrupt the proper clearances between moving parts, deteriorating lubrication conditions and accelerating engine wear.

[0003] For example, patent publication number CN116498431A discloses a return air baffle device for an engine cooling system. The device includes an L-shaped first and second return air baffles. The return air baffles are mounted around the left and right sides and bottom of an expansion tank. A rubber sheet is attached to the bottom of the return air baffle, which overlaps the top of a cooling module. By placing the return air baffle between the expansion tank and the cooling module and closely overlapping the flexible rubber sheet on the bottom of the return air baffle with the top of the cooling module, the return air baffle effectively reduces hot return air from the engine, thereby ensuring the return air baffle's windshield protection.

[0004] At present, the inventions regarding the engine hot return air baffle mainly focus on the improvement and creation of the structural form, but do not take into account the significant impact of the hot return air baffle on the internal resistance of the power compartment, and are difficult to flexibly adjust according to the driving characteristics of the vehicle in different seasons and regions. The functional effect is relatively simple, and when the engine is in high-temperature conditions in summer and the cooling capacity of the cooling system is insufficient, the fan of the cooling system needs to run at high speed to compensate, resulting in increased power consumption of the cooling system. Summary of the Invention

[0005] The purpose of the present invention is to overcome the above technical deficiencies and propose a return air device, return air system and return air method to solve the technical problem that the engine hot return air system in the prior art has low flexibility and is difficult to adaptively adjust the return air according to the vehicle conditions.

[0006] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides an air return device, comprising:

[0008] A diversion module, the diversion module is used to be arranged between the cab floor and the engine cooling module;

[0009] a connecting module, the connecting module being connected to one end of the diversion module and being used for connecting to the cab floor; and

[0010] The hinge module is fixed to the other end of the guide module and is used for hinge connection with the cooling module.

[0011] In some embodiments, the air guide module includes at least two return air plates, each of the return air plates is connected in sequence, and at least one of the return air plates can be hinged to the cooling module through the hinge module.

[0012] In some embodiments, the air guide module further includes at least one set of connecting members, each of which is respectively connected to each adjacent return air plate.

[0013] In some embodiments, each of the return air plates may be hinged to the cooling module via a hinge module, and each of the return air plates may drive the adjacent return air plates to rotate via a connecting member.

[0014] In some embodiments, the connecting member is a flexible member, and each of the connecting members is located between adjacent return air plates and extends from the lower end of the return air plate to the upper end of the return air plate.

[0015] In some embodiments, the connecting member includes a plurality of folding sheets, the width of each folding sheet gradually increases from bottom to top, and each folding sheet is connected in sequence through folds and can be folded in sequence through the folds.

[0016] In some embodiments, each of the return air plates is provided with a mounting hole, and the mounting hole is used for fixing the sensor.

[0017] In some embodiments, the connection module includes a flexible rubber sheet, one end of which is detachably fixed to the guide module, and the other end of which is used to overlap the cab floor.

[0018] In the second aspect, the present invention also provides a return air system, including a cooling module and a return air device, wherein the cooling module is used to be arranged on the side of the engine close to the air intake grille, the lower end of the guide module is hinged to the cooling module through the hinge module, and the upper end of the guide module is used to connect to the cab floor through the connection module.

[0019] In a third aspect, the present invention further provides an air return method, which is performed by an air return system and includes the following steps:

[0020] The air guide module blocks the return air from the engine compartment;

[0021] The air guide module rotates toward the engine to guide the airflow entering through the air intake grille toward the cooling module;

[0022] The air guide module guides the air flow entering through the air intake grille toward the air intake grille by rotating in a direction away from the engine.

[0023] Compared with the prior art, the beneficial effects of the return air device, return air system and return air method provided by the present invention include: the return air device is provided with a guide module, a connection module and a hinge module; the guide module can be provided between the cab floor and the engine cooling module to block the return air from the engine compartment and prevent the high-temperature airflow from re-entering the cooling module; the connection module is connected to one end of the guide module and can prevent the hot air from passing through the gap between the guide module and the cab floor by connecting to the cab floor; the return air device is provided with a hinge module so that the guide module can rotate relative to the engine cooling module; the guide module is provided with a hinge module By rotating away from the engine, the airflow entering through the air intake grille can be directed toward the cooling module, accelerating the cooling efficiency of the cooling module, thereby making the return air system more adaptable to high-temperature working conditions in summer, helping to improve the combustion efficiency and power of the engine in summer environments; the guide module rotates toward the engine, so that the airflow from the air intake grille into the power compartment will be guided in the direction of the air intake grille, and will not be directed into the cooling module, thereby reducing the cooling efficiency of the cooling module, making the return air system more adaptable to low-temperature working conditions of the engine, helping to improve the combustion efficiency and power of the engine in cold environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a structural schematic diagram of the connecting piece of the air return device provided by an embodiment of the present invention in a folded and stored state;

[0025] Figure 2 This is a structural schematic diagram of the connecting piece of the air return device provided by an embodiment of the present invention in an unfolded state;

[0026] Figure 3 2 is a schematic structural diagram of a connecting piece of a return air system provided by an embodiment of the present invention in a folded and stored state;

[0027] Figure 4 This is a structural schematic diagram of a connecting piece of a return air system provided by an embodiment of the present invention in an unfolded state;

[0028] Figure 5 This is a simulation diagram of the flow field distribution of the intake air flow when the guide module of the return air system provided by an embodiment of the present invention is in a vertical state;

[0029] Figure 6 This is a simulation diagram of the flow field distribution of the intake airflow when the guide module of the return air system provided by an embodiment of the present invention is tilted 30° toward the air intake grille;

[0030] Figure 7 This is a simulation diagram of the flow field distribution of the intake airflow when the guide module of the return air system provided by an embodiment of the present invention is tilted 45 degrees toward the air intake grille;

[0031] Figure 8 This is a simulation diagram of the flow field distribution of the intake air flow when the guide module of the return air system provided by an embodiment of the present invention is in a state of being tilted 60° toward the air intake grille.

[0032] Description of reference numerals:

[0033] 10—air guide module 11—return air plate 12—connector

[0034] 20—Articulated module 21—Articulated shaft 30—Cooling module

[0035] 31—Radiator 32—Intercooler 33—Piping system

[0036] 111 —Mounting hole 121 —Folded sheet 10a —Airflow. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0038] In order to solve the technical problem in the prior art that the engine heat return air system has low flexibility and is difficult to adaptively adjust the return air according to the vehicle conditions, the present invention provides a return air device, a return air system and a return air method. The return air device is installed between the cab floor and the engine cooling module to form a return air system, which can adaptively adjust the engine compartment air intake and return air according to different engine working conditions, thereby helping to improve the engine's combustion efficiency and power in cold and high temperature environments.

[0039] See also Figure 1-2 , Figure 1-2 Schematic diagram of the structure of the return air device in one embodiment of the present invention.

[0040] The return air device of an embodiment of the present invention includes a guide module 10, a connection module (not marked in the figure) and an articulation module 20. The guide module 10 is used to be arranged between the cab floor and the engine cooling module 30; the connection module is connected to one end of the guide module 10 for connecting to the cab floor; the articulation module 20 is fixed to the other end of the guide module 10 for articulation with the cooling module 30.

[0041] Specifically, the return air device is provided with a guide module 10, a connection module, and an articulation module 20. The guide module 10 can be provided between the cab floor and the engine cooling module 30 to block the return air from the engine compartment, preventing the high-temperature airflow 10a from re-entering the cooling module 30. The articulation module is connected to one end of the guide module 10 and, by connecting to the cab floor, prevents hot air from escaping through the gap between the guide module 10 and the cab floor. The return air device is provided with an articulation module 20, so that the guide module 10 can rotate relative to the engine cooling module 30, thereby controlling the return air according to the actual situation of the engine.

[0042] For example, in summer driving conditions, the air guide module 10 rotates away from the engine, so that the air guide module 10 forms an inclination angle toward the air intake grille. The air flow 10a blown into the engine compartment from the air intake grille no longer vertically impacts the air guide module 10 to form a vortex. The air guide module 10 tilted toward the air intake grille can guide the air flow 10a entering through the air intake grille toward the cooling module 30, and avoids convection with the air flow 10a entering through the air intake grille, thereby blocking the air flow 10a entering the air intake grille and preventing part of the air flow from passing through the air intake grille again. The air flows out of the cabin in the reverse direction, accelerating the cooling efficiency of the cooling module 30. In addition, because the air guide module 10 is tilted toward the air intake grille, the cooling airflow 10a entering the engine compartment through the air intake grille is accelerated to flow into the cooling module 30, thereby increasing the air intake speed on the cold side of the cooling module 30 and effectively improving the heat exchange capacity. As a result, the fan speed can be reduced accordingly, reducing the power consumption of the cooling system and improving the overall economy of the vehicle. In addition, the return air system is more suitable for high-temperature summer conditions, which helps to improve the combustion efficiency and power performance of the engine in high-temperature summer environments.

[0043] Under winter driving conditions, the air guide module 10 remains in a vertical state, or is rotated away from the engine so as to form an inclination angle toward the engine. In this case, the airflow 10a flowing into the power compartment from the air intake grille will be directed toward the air intake grille and will not be directed into the cooling module 30. The return air from the power compartment can be redirected to the cooling module 30, thereby reducing the cooling efficiency of the cooling module 30, making the return air system more adaptable to the low-temperature operating conditions of the engine, and helping to improve the combustion efficiency and power of the engine in cold environments.

[0044] In this embodiment, the rotation of the diversion module 10 can be controlled manually in the shutdown state, or by setting a rotating cylinder, motor and other driving components connected to the diversion module 10 or the articulated module 20. The driving components can adaptively adjust the diversion module 10 according to the real-time monitoring data of the vehicle.

[0045] It can be understood that the guide module 10 can be a whole guide plate hinged to the cooling module 30 through the connection module, and the size of the guide plate can be set according to the size of the model and vehicle type, and the shape and size of the cooling module 30.

[0046] In one embodiment, Figure 1-4 As shown, the air guide module 10 includes at least two return air panels 11, each of which is connected in sequence. At least one return air panel 11 can be hinged to the cooling module 30 via a hinge module 20. Specifically, by configuring the air guide module 10 as a split design with at least two return air panels 11, the airflow 10a in the power compartment can be more precisely controlled, thereby being able to adapt to various different engine operating conditions.

[0047] In this embodiment, the guide module 10 is provided with multiple return air plates 11, which not only breaks through the existing concept of integrated return air plates 11, but also improves the disadvantages caused by the return air plates 11 being arranged in a fixed state, which affects the flow field in the power cabin and the performance of the cooling module 30.

[0048] As will be appreciated, the air guide module 10 may be provided with n (n ≥ 2) return air plates 11. The number n of return air plates 11 and the geometric shape of each return air plate 11 can be designed and adjusted based on the aircraft model and vehicle characteristics. Each return air plate 11 can be simultaneously hinged to the cooling module 30 via the hinge module 20, or some of the return air plates 11 can be hinged to the cooling module 30, and the direction of the airflow 10a can be achieved simply by rotation.

[0049] In some embodiments, each return air plate 11 can be hingedly connected to the cooling module 30 via an articulated module 20, and each return air plate 11 can drive the rotation of adjacent return air plates 11 via a connector 12. Specifically, each return air plate 11 is hingedly connected to the cooling module 30, and the angle of each return air plate 11 can be individually adjusted based on the specific driving conditions of the vehicle (different ambient temperatures, regions, routes, etc.), thereby improving the precision of the airflow 10a adjustment.

[0050] It is understandable that the connecting member 12 may be a hinged rod with its two ends hinged to two adjacent return air plates 11 , or a flexible component with its two ends connected to two adjacent return air plates 11 .

[0051] It can be understood that the return air panels 11 can be independent of each other and controlled individually, or can be synchronously controlled through other connecting components.

[0052] In one embodiment, Figure 1-4As shown, the air guide module 10 further includes at least one set of connectors 12, each connector 12 being connected to each adjacent return air plate 11. Specifically, the return air plates 11 are connected by the connectors 12, so that only one return air plate 11 needs to be rotated, and the other return air plates 11 can be driven by the connectors 12 in sequence, thereby facilitating the control of the air guide module 10.

[0053] In one embodiment, Figure 1-4 As shown, the connector 12 is a flexible member. Each connector 12 is located between adjacent return air plates 11 and extends from the lower end of the return air plate 11 to the upper end of the return air plate 11. Specifically, by providing the flexible member between adjacent return air plates 11, the gaps between the return air plates 11 can be blocked while connecting the return air plates 11, thereby preventing the intake air flow 10a and the return air from passing through the gaps between the return air plates 11 through the guide module 10.

[0054] It is understandable that the flexible member can be a flexible member such as a flexible cloth, a flexible silicone, a flexible metal member, etc., which can be expanded and contracted as the return air plate 11 rotates.

[0055] In one embodiment, Figure 1-4 As shown, the connecting piece 12 includes a plurality of folding pieces 121. The width of each folding piece 121 gradually increases from bottom to top. Each folding piece 121 is connected in sequence by folds and can be folded in sequence by the folds. Specifically, by setting the connecting piece as a plurality of folding pieces 121 connected in sequence by folds, the surface of the connecting piece 12 can form a folding fan structure. The connecting piece 12 of this structure can be freely unfolded and folded by rotating the return air plates 11 on both sides, as shown in FIG. Figure 2 and 4 As shown, in the unfolded state, the connecting piece unfolds to form a fan shape, which allows the return air plates 11 on both sides to form any angle within a certain range, thereby adapting to the working conditions of the engine. In the retracted state, as shown Figure 1 and 3 As shown, it can be folded and stored between the two return air plates 11 and be flush with the two return air plates 11.

[0056] In this embodiment, the angle corresponding to the fully extended connector 12 is the same as the designed maximum angle between adjacent return air panels 11. The gap between adjacent return air panels 11 is determined by the thickness of the foldable fan-shaped connector when fully folded. Therefore, different connector materials, different connector thicknesses, different designed maximum angles, and different folding methods will all affect the gap between adjacent return air panels 11.

[0057] In this embodiment, Figure 1-4As shown, since the connecting member 12 is in an inverted trapezoidal shape after being fully folded, the connecting side of the return air plate 11 and the connecting member 12 is also adaptively beveled at a corresponding angle.

[0058] It is understandable that fixing structures such as bolt holes can be added to each return air plate 11, which can be used to fix smaller components such as wiring harnesses in the power compartment.

[0059] In one embodiment, Figure 1-4 As shown, each return air plate 11 is provided with a mounting hole 111 for securing sensors. Specifically, mounting holes 111 can be used to attach sensing components such as a micro gas flow sensor and anemometer. This allows the cooling air velocity at the top of the cooling module 30 to be measured when each return air plate 11 is tilted at different angles. This allows the real-time heat exchange capacity of the cooling module 30 to be estimated. This, combined with data such as the engine operating status and vehicle driving status, as well as the electric adjustment mechanism of the deflector, electronic water pump, and electronic fan, enables adaptive adjustments, ultimately achieving predictive intelligent thermal management of the vehicle.

[0060] It is understandable that the connection module can be a connection piece such as sponge, silicone, etc. that can always remain connected to the cab floor.

[0061] In one embodiment, the connection module includes a flexible rubber sheet, one end of which is fixed to the air guide module 10, and the other end of which overlaps the cab floor. Specifically, the flexible rubber sheet ensures that the connection module always overlaps the cab floor, regardless of the angle at which the air guide module 10 is installed. This overlap between the flexible rubber sheet and the cab floor prevents side air leakage, air leakage, and hot air return, thereby preventing hot return air from mixing with cooler outside air and then entering the cooling module 30.

[0062] In this embodiment, a flexible rubber sheet is provided at the upper end of each return air plate 11. For a rectangular return air plate 11 (length L * height H * thickness S), its height is H when vertically positioned. However, after rotating it a certain angle toward the engine or the air intake grille, its frontal area decreases from LH to sinθ LH, and the headwind resistance is reduced accordingly. This leaves an excess gap (1-sinθ) H in the vertical height of the return air plate 11. This gap can be filled by adding a flexible rubber sheet to the upper end of the air guide module 10.

[0063] In this embodiment, the flexible rubber sheet is detachably connected to the air guide module 10. When the engine is operating under low-temperature conditions, the flexible rubber sheet can be removed from the air guide module 10 and maintained in a vertical state in conjunction with the air guide module 10, or rotated away from the engine to reasonably control a certain proportion of hot return air. The hot return air is mixed with the lower external air and then enters the cooling module 30, which helps to improve the combustion efficiency and power of the engine in a cold environment.

[0064] In this embodiment, Figure 1-4 As shown, the hinge module 20 is a hinge shaft 21 fixed to the lower end of the air guide module 10. The cooling module 30 is provided with an axially extending hinge slot. The hinge shaft 21 at the lower end of the air guide module 10 is installed in the hinge slot of the cooling module 30, thereby achieving an articulated connection between the air guide module 10 and the cooling module 30. The hinge shaft 21 can be installed on all return air panels 11 to achieve an articulated connection between all return air panels 11 and the cooling module 30. The relative rotation angle of each return air panel 11 can be adjusted according to the specific driving conditions of the vehicle (different ambient temperatures, regions, routes, etc.). After the panel is rotated to a specific angle, it is fixed to the hinge shaft 21 by bolts and nuts located on both sides of the return air panel 11.

[0065] It can be understood that the hinge module 20 can also be a shaft sleeve fixed to the lower end of the air guide module 10, and the cooling module 30 is provided with an axially extending fixed shaft. The shaft sleeve at the lower end of the air guide module 10 is sleeved on the hinge groove of the cooling module 30 to realize the hinge connection between the air guide module 10 and the cooling module 30, wherein the shaft sleeve can be provided on all return air plates 11 to realize the hinge connection between all return air plates 11 and the cooling module 30. When the partition plate is rotated to a specific angle, it is fixed to the fixed shaft by the bolts and nuts located on both sides of the return air plate 11.

[0066] It can be understood that the hinge module 20 can also be a hinge protrusion arranged on both sides of each return air plate 11. The hinge protrusion is installed through a hinge hole on the cooling module 30 or the adjacent return air plate 11 to achieve the hinge connection between each return air plate 11 and the cooling module 30.

[0067] The return air system of the embodiment of the present invention is as follows: Figure 3-4 As shown, it includes a cooling module 30 and a return air device. The cooling module 30 is used to be arranged on the side of the engine close to the air intake grille. The lower end of the guide module 10 is hinged to the cooling module 30 through the hinge module 20, and the upper end of the guide module 10 is used to connect to the cab floor through the connection module.

[0068] In this embodiment, the cooling module 30 includes a radiator 31, an intercooler 32 and a pipe system 33. The intercooler 32 is fixed to one side of the radiator 31.

[0069] Specifically, the return air system is provided with the return air device, and the return air system is installed on the vehicle. When the vehicle is driven in summer, the guide module 10 is rotated in the direction away from the engine, so that the guide module 10 forms an inclination angle in the direction of the air intake grille. The airflow 10a blown into the power compartment from the air intake grille no longer vertically impacts the guide module 10 to form a vortex. The guide module 10 tilted in the direction of the air intake grille can guide the airflow 10a entering through the air intake grille toward the cooling module 30, and avoids convection with the airflow 10a entering through the air intake grille, thereby blocking the airflow 10a entering the air intake grille and preventing some air from entering the vehicle. The airflow then flows out of the cabin again from the air intake grille in the opposite direction, accelerating the cooling efficiency of the cooling module 30. In addition, since the air guide module 10 is tilted toward the air intake grille, the cooling airflow 10a entering the engine compartment through the air intake grille is accelerated to flow into the cooling module 30, thereby increasing the air intake speed on the cold side of the intercooler 32 and the heat exchanger of the cooling module 30, which can effectively improve the heat exchange capacity. Therefore, the fan speed can be reduced accordingly, reducing the power consumption of the cooling system and improving the overall economy of the vehicle. In addition, the return air system is more suitable for high temperature conditions in summer, which helps to improve the combustion efficiency and power performance of the engine in high temperature environments in summer.

[0070] Under winter driving conditions, the air guide module 10 remains in a vertical state, or is rotated away from the engine so as to form an inclination angle toward the engine. In this case, the airflow 10a flowing into the power compartment from the air intake grille will be directed toward the air intake grille and will not be directed into the cooling module 30. The return air from the power compartment can be redirected to the cooling module 30, thereby reducing the cooling efficiency of the cooling module 30, making the return air system more adaptable to the low-temperature operating conditions of the engine, and helping to improve the combustion efficiency and power of the engine in cold environments.

[0071] Furthermore, the guide module 10 of the return air device is provided with a plurality of rotatable return air plates 11, and can adaptively control the airflow 10a of the power compartment according to the operating conditions of the vehicle, thereby keeping the engine in the best operating state.

[0072] The air return method according to the embodiment of the present invention is performed by a return air system and includes the following steps:

[0073] The air guide module 10 blocks the return air from the engine compartment;

[0074] The air guide module 10 rotates toward the engine to guide the air flow 10a entering through the air intake grille toward the cooling module 30;

[0075] The air guide module 10 guides the air flow 10a entering through the air intake grille toward the air intake grille by rotating in a direction away from the engine.

[0076] Specifically, by controlling the return air and intake air flow 10a through the guide module 10, the intake and return air in the engine compartment can be adaptively adjusted according to different operating conditions of the engine, thereby helping to improve the combustion efficiency and power of the engine in cold and high temperature environments.

[0077] In this embodiment, combined with Figure 5-8 As shown in the flow field distribution simulation diagram of the intake airflow 10a entering the middle air intake grille, during the flow field control process, the angle between the guide module 10 and the cooling module 30 should not be too large. As shown in the figure, as the inclination angle of the guide module 10 gradually increases between 0° and 60°, the vortex formed by the airflow 10a entering through the air intake grille in front of the hot return air baffle gradually disappears, and the airflow entering the upper part of the cooling module 30 flows into the cooling module 30 at a more reasonable angle under the guidance of the return air plate 11; however, when the inclination angle increases to a certain extent, part of the airflow in the upper air intake grille flows into the power compartment from above the return air plate 11, and this part of the airflow is not fully utilized.

[0078] The specific embodiments of the present invention described above do not limit the scope of protection of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. A return air device, characterized in that: include: A diversion module, the diversion module is used to be arranged between the cab floor and the engine cooling module; a connecting module, the connecting module being connected to one end of the diversion module and being used for connecting to the cab floor; as well as an articulated module, the articulated module being fixed to the other end of the flow guide module and being configured to be articulated with the cooling module; The air guide module includes at least two return air plates, each of which is connected in sequence, and at least one of the return air plates can be hinged to the cooling module through the hinge module; The air guide module further includes at least one set of connecting members, each of which is connected to each adjacent air return plate; The connecting member includes a plurality of folding sheets, the width of each folding sheet gradually increases from bottom to top, and each folding sheet is connected in sequence through folds and can be folded in sequence through the folds.

2. The air return device according to claim 1, characterized in that: Each of the return air plates can be hinged to the cooling module via a hinge module, and each of the return air plates can drive the adjacent return air plates to rotate via a connecting piece.

3. The air return device according to claim 1, characterized in that: The connecting member is a flexible member, and each connecting member is located between adjacent return air plates and extends from the lower end of the return air plate to the upper end of the return air plate.

4. The air return device according to claim 1, characterized in that: Each of the return air plates is provided with a mounting hole, and the mounting hole is used for fixing the sensor.

5. The air return device according to any one of claims 1 to 4, characterized in that: The connection module includes a flexible rubber sheet, one end of which is detachably fixed to the guide module, and the other end of which is used to overlap the cab floor.

6. A return air system, characterized in that: It includes a cooling module and the return air device according to any one of claims 1 to 5, the cooling module is used to be arranged on the side of the engine close to the air intake grille, the lower end of the guide module is hinged to the cooling module through the hinge module, and the upper end of the guide module is used to connect to the cab floor through the connection module.

7. A return air method, characterized in that: The method is performed by the return air system according to claim 6, comprising the following steps: The air guide module blocks the return air from the engine compartment; The air guide module rotates toward the engine to guide the airflow entering through the air intake grille toward the cooling module; The air guide module guides the air flow entering through the air intake grille toward the air intake grille by rotating in a direction away from the engine.

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