Power cabin and construction machinery having the same

Abstract

The present invention relates to a power cabin and a construction machinery having the same. The power cabin includes: a cabin; an engine disposed in the cabin and having a coolant flow path for circulating coolant; a radiator disposed in the cabin and communicating with the coolant flow path of the engine; a ventilation opening disposed on the cabin and used for introducing air for heat exchange with the radiator or discharging air after heat exchange with the radiator; a noise reduction unit disposed on the ventilation opening. The noise reduction unit includes a first grille, a second grille stacked with the first grille in the thickness direction of the cabin wall and having an adjustable distance from the first grille, and a first elastic member for pushing the first grille towards the second grille. The first grille includes a plurality of first air vents arranged side by side and a first solid part located between two adjacent first air vents. The second grille includes a plurality of second air vents arranged side by side and a second solid part located between two adjacent second air vents. The projection of the second air vent in a plane perpendicular to the thickness direction partially or completely overlaps with the projection of the first solid part in the plane, so that the air outlet of the second air vent drives the first grille in a direction away from the second grille.

Description

Technical Field

[0001] The present invention relates to the field of construction machinery, and in particular, to a power cabin and a construction machinery having the same. Background Art

[0002] With the development of the construction machinery industry, the noise of construction machinery has attracted more and more attention, and national standards have been established at home and abroad to limit it. The components of the noise inside the engine cabin of construction machinery are complex, and the noise is composed of various noise components such as aerodynamic, mechanical transmission, and hydraulic noise. The noise forms a reverberant sound field after multiple reflections and interferences on the inner wall of the power cabin, further increasing the overall machine noise.

[0003] As one of the main noise sources inside the power cabin, the cooling fan has an important impact on both the noise and heat dissipation performance of construction machinery. The fan noise is the eddy current noise formed by the periodic excitation of air by the fan blades. This periodic pressure pulsation is composed of a steady fundamental frequency and a series of harmonic components. The air volume of the fan, the noise frequency, and the rotational speed of the fan are directly proportional. The higher the fan speed, the higher the noise frequency, sound pressure level, and cooling air volume of the fan.

[0004] The power cabin hood is an important part of construction machinery, which plays the roles of appearance, heat dissipation, isolation, and absorption of the noise inside the power cabin. For the cooling system, some air vents are opened on the power cabin hood, and these air vents directly transmit the noise inside the power cabin. The air vents are a main path for noise transmission. The larger the area of the air vents, the weaker the sound insulation effect of the power cabin hood.

[0005] The perforated panel resonance sound absorption structure is composed of a perforated panel-shaped material and the cavity behind it. The sound absorption frequency of the perforated panel resonance sound absorption structure is related to the perforation rate of the perforated panel and the thickness of the cavity behind it. The smaller the thickness of the cavity behind, the larger the sound absorption frequency. Summary of the Invention

[0006] The present invention aims to provide a power cabin and a construction machinery having the same to improve the contradiction between the opening area of the power cabin hood and the sound absorption and insulation performance.

[0007] According to one aspect of the embodiments of the present invention, the present invention provides a power cabin, which includes:

[0008] A cabin;

[0009] An engine, disposed in the cabin and having a coolant flow path for circulating coolant;

[0010] A radiator, disposed in the cabin and communicating with the coolant flow path of the engine;

[0011] A ventilation opening, which is provided on the cabin and is used to introduce air that exchanges heat with the radiator or discharge air that has exchanged heat with the radiator; and

[0012] A noise reduction unit, which is provided on the ventilation opening. The noise reduction unit includes a first grille, a second grille that is stacked with the first grille along the thickness direction of the cabin wall and has an adjustable distance from the first grille, and a first elastic member that presses the first grille towards the second grille. The first grille includes a plurality of first air vents arranged side by side and a first solid part located between two adjacent first air vents. The second grille includes a plurality of second air vents arranged side by side and a second solid part located between two adjacent second air vents. The projection of the second air vent in a plane perpendicular to the thickness direction partially or completely overlaps with the projection of the first solid part in the plane, so that the air flow out of the second air vent drives the first grille in a direction away from the second grille.

[0013] In some embodiments, the power cabin further includes a third grille provided on the side of the first grille away from the second grille. The third grille includes a plurality of third air vents arranged side by side and a third solid part located between two adjacent third air vents. The projection of the third solid part and the first solid part in the plane partially or completely overlaps. The power cabin further includes a first shielding member that extends around the edge of the first solid part to enclose a first chamber with the first solid part and the third solid part. A plurality of first through holes communicating with the first chamber are provided on the first solid part to form a perforated panel resonance sound absorption structure.

[0014] In some embodiments, the first shielding member includes a flexible member. One end of the flexible member is connected to the first solid part, and the other end is connected to the third solid part.

[0015] In some embodiments, the projection of the third air vent and the first air vent in the plane partially or completely overlaps.

[0016] In some embodiments, the first elastic member is provided between the first grille and the third grille. One end of the first elastic member abuts against the first grille, and the other end abuts against the third grille.

[0017] In some embodiments,

[0018] The second grille, the first grille, and the third grille are arranged in sequence from upstream to downstream along the air flow direction in the ventilation opening; or

[0019] The second grille, the first grille, and the third grille are arranged in sequence from downstream to upstream along the air flow direction in the ventilation opening.

[0020] In some embodiments,

[0021] The first grille is installed in the ventilation opening and is configured to be slidable along the thickness direction relative to the cabin to adjust the distance between the first grille and the second grille; and / or

[0022] The third grille is fixedly installed in the ventilation opening.

[0023] In some embodiments, the power cabin further includes a fourth grille provided on a side of the second grille away from the first grille. The fourth grille includes a plurality of fourth air vents arranged side by side and a fourth solid part located between two adjacent fourth air vents. The projection of the fourth solid part on a plane partially or completely overlaps with the projection of the second solid part.

[0024] In some embodiments,

[0025] The projection of the fourth air vent and the second air vent on a plane partially or completely overlaps; and / or

[0026] The projection of the first air vent and the second solid part on a plane partially or completely overlaps.

[0027] In some embodiments,

[0028] The second grille is installed in the ventilation opening and is configured to be slidable relative to the cabin in the thickness direction to adjust the distance between the first grille and the second grille; and / or

[0029] The fourth grille is fixedly installed in the ventilation opening.

[0030] In some embodiments, the power cabin further includes a second elastic member that pushes the second grille toward the first grille. The second elastic member is provided between the second grille and the fourth grille.

[0031] In some embodiments, the power cabin further includes a second shielding member that extends around the edge of the second solid part to enclose a second chamber with the second solid part and the fourth solid part. The fourth solid part is provided with a second through hole communicating with the second chamber to form a perforated panel resonance sound absorption structure.

[0032] In some embodiments, the second shielding member includes a first plate-like member and a second plate-like member erected between the second grille and the fourth grille.

[0033] The first plate-like member and the second plate-like member are respectively fixedly connected to two sides of the second solid part. The fourth solid part is located between the first plate-like member and the second plate-like member and can slide relative to the first plate-like member and the second plate-like member in the thickness direction; or

[0034] The first plate-like member and the second plate-like member are respectively fixedly connected to two sides of the fourth solid part. The second solid part is located between the first plate-like member and the second plate-like member and can slide relative to the first plate-like member and the second plate-like member in the thickness direction.

[0035] In some embodiments,

[0036] The fourth grille, the second grille, and the first grille are arranged in sequence from upstream to downstream along the air flow direction in the ventilation opening; or

[0037] The fourth grille, the second grille, and the first grille are arranged in sequence from downstream to upstream along the air flow direction in the ventilation opening.

[0038] According to another aspect of the present invention, an engineering vehicle is further provided, and the engineering vehicle includes the above-mentioned power cabin.

[0039] Applying the technical solution of the present application, during the process of air flowing from the second grille towards the first grille, the air passing through the second air vent exerts a pressure on the first solid part. After this pressure is greater than the elastic force of the first elastic component, the first grille moves away from the second grille to form a flow port between the first grille and the second grille, and the opening degree of this flow port increases as the pressure exerted by the air on the first solid part increases. The pressure exerted by the air on the first solid part is positively correlated with the rotational speed of the fan driving the air to flow through the radiator, and the noise frequency of the fan is positively correlated with the rotational speed of the fan. Therefore, the noise reduction unit of this embodiment can adjust the opening degree of the flow port according to the rotational speed of the fan, ensuring smooth air flow on the premise of ensuring the sound absorption and insulation effect, and improving the problem in the related art that the sound insulation component affects air flow and thus affects the heat dissipation of the power cabin.

[0040] Through the following detailed description of the exemplary embodiments of the present invention with reference to the accompanying drawings, other features and advantages of the present invention will become clear. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0042] Figure 1 Shows a three-dimensional structural schematic diagram of the power cabin of the embodiment of the present invention;

[0043] Figure 2 Shows a structural schematic diagram of the power cabin when the noise reduction unit of the embodiment of the present invention is opened;

[0044] Figure 3 Shows a structural schematic diagram of the power cabin when the noise reduction unit of the embodiment of the present invention is opened from another angle; and

[0045] Figure 4 Shows a structural schematic diagram of the noise reduction unit of the power cabin of the embodiment of the present invention;

[0046] Figure 5 Shows a schematic structural diagram of the noise reduction unit of the power cabin from another angle of the embodiment of the present invention;

[0047] Figure 6 Shows an exploded view of the schematic structural diagram of the noise reduction unit of the power cabin of the embodiment of the present invention;

[0048] Figure 7 Shows a schematic diagram of the air flow direction of the power cabin of the embodiment of the present invention;

[0049] Figure 8 Shows a schematic diagram of the air flow direction of the noise reduction unit on the exhaust port of the power cabin of the embodiment of the present invention;

[0050] Figure 9 Shows a schematic diagram of the air flow direction of the power cabin of the embodiment of the present invention; and

[0051] Figure 10 Shows a schematic diagram of the air flow direction of the noise reduction unit on the air inlet of the power cabin of the embodiment of the present invention. Detailed implementation manners

[0052] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and in no way limits the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0053] Combined with Figures 1 to 7 As shown, the power cabin of this embodiment includes a cabin 20, an engine 60, a radiator 40, a ventilation port 30, and a noise reduction unit 10. The engine 60 is arranged in the cabin 20 and has a coolant flow path for circulating coolant. The radiator 40 is arranged in the cabin 20 and is communicated with the coolant flow path of the engine 60. The ventilation port 30 is arranged on the cabin 20 and is used to introduce air for heat exchange with the radiator 3 or discharge air after heat exchange with the radiator 40.

[0054] As Figure 6As shown in the figure, the noise reduction unit 10 is provided on the ventilation opening 30. The noise reduction unit 10 includes a first grille 2, a second grille 3 that is stacked with the first grille 2 in the thickness direction of the wall of the cabin 20 and the distance between the second grille 3 and the first grille 2 is adjustable, and a first elastic member 8 that presses the first grille 2 toward the second grille 3. The first grille 2 includes a plurality of first air vents 21 arranged side by side and a first solid portion 22 located between two adjacent first air vents 21. The second grille 3 includes a plurality of second air vents 31 arranged side by side and a second solid portion 32 located between two adjacent second air vents 31. The projection of the second air vent 31 in the plane perpendicular to the thickness direction partially or completely overlaps with the projection of the first solid portion 22 in the plane, so that the air flowing out of the second air vent 31 drives the first grille 2 in a direction away from the second grille 3.

[0055] During the process of air flowing from the second grille 3 toward the first grille 2, the air passing through the second air vent 31 exerts pressure on the first solid portion 22. After this pressure is greater than the elastic force of the first elastic member 8, the first grille 2 moves in a direction away from the second grille 3 to form a flow-through opening between the first grille 2 and the second grille 3, and the opening degree of this flow-through opening increases as the pressure exerted by the air on the first solid portion 22 increases. The pressure exerted by the air on the first solid portion 22 is positively correlated with the rotational speed of the fan 50 that drives the air to flow through the radiator 40, and the noise frequency of the fan 50 is positively correlated with the rotational speed of the fan 50. Therefore, the noise reduction unit 1 of this embodiment can adjust the opening degree of the flow-through opening according to the rotational speed of the fan 50, and can ensure smooth air flow on the premise of ensuring the sound insulation effect, improving the problem in the related art that the sound insulation component affects air flow and thus affects the heat dissipation of the power cabin.

[0056] In some embodiments, the projection of the second air vent 31 in the plane perpendicular to the thickness direction overlaps with the projection of the first solid portion 22 in the plane.

[0057] The power cabin further includes a third grille 1 provided on the side of the first grille 2 away from the second grille 3. The third grille 1 includes a plurality of third air vents 11 arranged side by side and a third solid portion 12 located between two adjacent third air vents 11. The projection of the third solid portion 12 and the first solid portion 22 partially or completely overlaps in the plane. The power cabin further includes a first shielding member 7. The first shielding member 7 extends around the edge of the first solid portion 22 to enclose a first chamber 5 with the first solid portion 22 and the third solid portion 12. A plurality of first through holes 23 communicating with the first chamber 5 are provided on the first solid portion 22 to form a perforated panel resonance absorption structure (Helmholtz resonance absorption structure).

[0058] The thickness of the first chamber 5 decreases as the pressure exerted by the air on the first solid part 22 increases. The pressure exerted by the air on the first solid part 22 is positively correlated with the rotational speed of the fan 50 that drives the air to flow through the radiator 40, and the noise frequency of the fan 50 is positively correlated with the rotational speed of the fan 50. Therefore, the noise reduction unit 1 of this embodiment can adjust the opening degree of the flow port and the thickness of the first chamber 5 according to the rotational speed of the fan 50, and further adjust the resonance absorption frequency of the first chamber 5, solve the contradiction between the area of the ventilation port 30 in the engine compartment and the sound insulation performance, so that the opening degree of the flow port meets the requirements of heat dissipation and noise reduction, and realize the coordinated improvement of the sound insulation, noise reduction and heat dissipation performance of the engine compartment hood.

[0059] In some embodiments, the projections of the third solid part 12 and the first solid part 22 in the plane overlap.

[0060] In some embodiments, the first shielding member 7 includes a flexible member. One end of the flexible member is connected to the first solid part 22, and the other end is connected to the third solid part 12. When the first grille 2 moves away from the second grille 3 under the action of the air pressure against the elastic force of the first elastic member 8, the flexible member shortens due to being bent, and when the first grille 2 moves towards the second grille 3, the flexible member elongates due to stretching.

[0061] The projection of the third air outlet 11 and the first air outlet 21 in the plane partially or completely overlap. As Figure 8 shown, since the shielding member 7 extends along the edge of the first solid part 22, the shielding member simultaneously encloses a flow channel connecting the first air outlet 21 and the third air outlet 11. When the air flows from the second grille 3 towards the first grille 2, the first grille 2 moves away from the second grille 3 under the action of the air pressure, so as to form a flow port between the first grille 2 and the second grille 3, and the air sequentially flows through the second air outlet 31 on the second grille 3, the flow port formed between the second grille 3 and the first grille 2, and the flow channel located between the first air outlet 21 and the third air outlet 11.

[0062] The first elastic member 8 is arranged between the first grille 2 and the third grille 1. One end of the first elastic member 8 abuts against the first grille 2, and the other end abuts against the third grille 1.

[0063] The second grille 3, the first grille 2 and the third grille 1 are arranged in sequence from upstream to downstream along the air flow direction in the ventilation port 30.

[0064] As Figures 1 to 3 shown in FIGS. 6, 7 and 9, the engine compartment includes two ventilation ports 30, and each ventilation port 30 is respectively provided with a noise reduction unit 10. One of the two ventilation ports 30 is an air inlet, and the other is an air outlet.

[0065] Two ventilation openings 30 are respectively provided at both ends of the engine 60. Optionally, the radiator 40, the fan 50, and the engine 60 are arranged side by side in sequence between the two ventilation openings 30.

[0066] In this embodiment, the third grilles 1 of the two noise reduction units 10 respectively provided on the two ventilation openings 30 are both located outside the first grille 2. In the noise reduction unit 10 installed on the air outlet, the second grille 3, the first grille 2, and the third grille 1 are arranged in sequence from upstream to downstream along the air flow direction in the ventilation opening 30. In the noise reduction unit 10 installed on the air inlet, the second grille 3, the first grille 2, and the third grille 1 are arranged in sequence from downstream to upstream along the air flow direction in the ventilation opening 30.

[0067] The noise reduction unit of the engine compartment in this embodiment realizes the coordinated improvement of the sound insulation, noise reduction, and heat dissipation performance of the engine compartment hood, and is applicable to the operating conditions where the air flow flows bidirectionally inside the engine compartment.

[0068] As Figure 7 shown, in some embodiments, the fan 50 is a blowing fan, the ventilation opening 30 at the end of the engine 60 far from the fan 50 is the air inlet, and the ventilation opening 30 at the end of the engine 60 adjacent to the fan 50 is the air outlet.

[0069] As Figure 9 shown, in some other embodiments, the fan 50 is a suction fan, the ventilation opening 30 at the end of the engine 60 far from the fan 50 is the air outlet, and the ventilation opening 30 at the end of the engine 60 adjacent to the fan 50 is the air inlet.

[0070] In some other embodiments, in the two noise reduction units 10 respectively installed on the air inlet and the air outlet, the second grille 3, the first grille 2, and the third grille 1 are arranged in sequence from upstream to downstream along the air flow direction in the ventilation opening 30.

[0071] The first grille 2 is installed in the ventilation opening 30 and is configured to be slidable in the thickness direction relative to the compartment 20 to adjust the distance between the first grille 2 and the second grille 3. The third grille 1 is fixedly installed in the ventilation opening 30.

[0072] The noise reduction unit 10 further includes a first guiding member 14 for guiding the first grille 2 to move in the thickness direction of the wall of the compartment 20. Optionally, the first guiding member 14 is provided on the third grille 1.

[0073] As Figure 6As shown, the power cabin further includes a fourth grille 4 disposed on the side of the second grille 3 away from the first grille 2. The fourth grille 4 includes a plurality of fourth air vents 41 arranged side by side and fourth solid parts 42 located between two adjacent fourth air vents 41. The projection of the fourth solid part 42 on the plane partially or completely overlaps with the projection of the second solid part 32.

[0074] The projection of the fourth air vent 41 and the second air vent 31 on the plane partially or completely overlaps. The projection of the first air vent 21 and the second solid part 32 on the plane partially or completely overlaps.

[0075] The second grille 3 is installed in the air vent 30 and is configured to be slidable in the thickness direction relative to the cabin 20 to adjust the distance between the first grille 2 and the second grille 3; the fourth grille 4 is fixedly installed in the air vent 30.

[0076] The noise reduction unit 10 further includes a grille bracket 13. The third grille 1 and the fourth grille 4 are respectively fixedly connected to the grille bracket 13. The noise reduction unit 10 further includes a second guiding member 34 for guiding the second grille 3 to move in the thickness direction of the wall of the cabin 20.

[0077] The power cabin further includes a second elastic member 9 that presses the second grille 3 toward the first grille 2. The second elastic member 9 is disposed between the second grille 3 and the fourth grille 4.

[0078] The power cabin further includes a second shielding member 35 that extends around the edge of the second solid part 32 to enclose a second chamber 6 with the second solid part 32 and the fourth solid part 42. A second through hole 43 communicating with the second chamber 6 is provided on the fourth solid part 42 to form a perforated panel resonance absorption structure (Helmholtz resonance absorption structure).

[0079] During the process of air flowing from the first grille 2 toward the second grille 3, the air passing through the first air vent 21 exerts pressure on the second solid part 32. After this pressure is greater than the elastic force of the second elastic member 9, the second grille 3 moves in a direction away from the first grille 2 to form a flow port between the first grille 2 and the second grille 3, and the opening degree of this flow port increases as the pressure exerted by the air on the second solid part 32 increases. The pressure exerted by the air on the second solid part 32 is positively correlated with the rotational speed of the fan 50 that drives the air to flow through the radiator 40. Therefore, the noise reduction unit 1 of this embodiment can adjust the opening degree of the flow port according to the rotational speed of the fan 50.

[0080] The power cabin further includes a second shielding member 35 that extends around the edge of the second solid part 32 to enclose a second chamber 6 with the second solid part 32 and the fourth solid part 42. A second through hole 43 communicating with the second chamber 6 is provided on the fourth solid part 42 to form a perforated panel resonance absorption structure.

[0081] The thickness of the second chamber 6 decreases as the pressure exerted by the air on the first solid part increases. The pressure exerted by the air on the second solid part 32 is positively correlated with the rotational speed of the fan 50 that drives the air to flow through the radiator 40, and the noise frequency of the fan 50 is positively correlated with the rotational speed of the fan 50. Therefore, the noise reduction unit 1 of this embodiment can adjust the opening degree of the flow port and the thickness of the second chamber 6 according to the rotational speed of the fan 50, and further adjust the resonance absorption frequency of the second chamber 6, solve the contradiction between the area of the ventilation port 30 in the power cabin and the sound absorption and insulation performance, and realize the coordinated improvement of the sound insulation, noise reduction, and heat dissipation performance of the power cabin hood.

[0082] The second shielding member 35 includes a first plate-like member 351 and a second plate-like member 352 erected between the second grille 3 and the fourth grille 4.

[0083] The first plate-like member 351 and the second plate-like member 352 are respectively fixedly connected to both sides of the second solid part 32, and the fourth solid part 42 is located between the first plate-like member 351 and the second plate-like member 352 and can slide relative to the first plate-like member 351 and the second plate-like member 352 in the thickness direction.

[0084] The first plate-like member 351 and the second plate-like member 352 are respectively fixedly connected to both sides of the fourth solid part 42, and the second solid part 32 is located between the first plate-like member 351 and the second plate-like member 352 and can slide relative to the first plate-like member 351 and the second plate-like member 352 in the thickness direction.

[0085] As Figure 7 shown, in some embodiments, the fan 50 is a blowing fan. The ventilation port 30 at the end of the engine 60 far from the fan 50 is an air inlet, and the ventilation port 30 at the end of the engine 60 adjacent to the fan 50 is an air outlet. In the noise reduction unit 10 installed on the air outlet, the fourth grille 4, the second grille 3, the first grille 2, and the third grille 1 are arranged from the inside to the outside and from the upstream to the downstream along the air flow direction in the ventilation port 30, as Figure 8 shown. In the noise reduction unit 10 installed on the air inlet, the fourth grille 4, the second grille 3, the first grille 2, and the third grille 1 are arranged from the inside to the outside in sequence and from the downstream to the upstream along the air flow direction in the ventilation port 30.

[0086] The following takes the fan 50 as a blowing fan as an example in combination with Table 1 to introduce the various working conditions of the power cabin of this embodiment:

[0087] Working condition 1: The engine is in a stopped state, the rotational speed of the fan 50 is 0, the noise reduction unit 10 is in an initial state, the first grille 2 and the second grille 3 are attached together, the first solid part 22 blocks the second air outlet 31, and at this time, the air outlet and the air inlet are in a sealed and non-ventilated state, and the air flow rate M in the power cabin = 0;

[0088] Technical effect: It avoids problems such as external dust pollution inside the power cabin and long-term blockage of the radiator 40.

[0089] Condition 2: The engine is in a cold start state, the water temperature is lower than 80 °C, generating a noise frequency Fs0. At this time, the rotational speed of the fan 50 is 0, the opening degree D1 of the flow-through opening between the first grille 2 and the second grille 3 corresponding to the noise reduction unit 10 at the air outlet is 0, the thickness V1 of the first chamber 5 is V1 = V1max in the maximum state, the corresponding noise elimination frequency Fe1 = Fe1min is the lowest, the opening degree D2 of the flow-through opening between the first grille 2 and the second grille 3 corresponding to the noise reduction unit 10 at the air inlet is 0, the thickness V2 of the second chamber 6 is V2 = V2max in the maximum state, the corresponding noise elimination frequency Fe2 = Fe2min is the lowest. At this time, the air outlet and the air inlet are in a sealed and non-ventilated state, and the air flow rate M of the power cabin is 0;

[0090] Technical effect: The sealed power cabin promotes the engine temperature to quickly rise to the normal operating temperature above 80 °C, improves the fuel economy of the engine, and has a good sound insulation effect on the noise inside the engine hood; at the same time, the noise frequency Fs0 generated by the engine is effectively absorbed by the noise elimination frequency Fe1min generated by the first chamber 5 and the noise elimination frequency Fe2min generated by the second chamber 6.

[0091] Condition 3: The engine is in a normal operating state, the rotational speed RpmFan of the fan 50 is in gear 1, and the engine 60 and the fan 50 generate a noise frequency Fs1.

[0092] The second grille 3 corresponding to the noise reduction unit 10 at the air inlet is affected by the negative pressure generated by the cooling fan 50 and moves along the second guiding member 34. After balancing with the negative pressure generated by the cooling fan 50 under the action of the second elastic member 9, it stops. The cooling air flows into the power cabin. At this time, the opening degree D2 of the flow-through opening between the first grille 2 and the second grille 3 is the opening degree 4, the thickness of the second chamber 6 becomes smaller, the thickness V2 of the second chamber 6 is V2 = V21, and the corresponding noise elimination frequency Fe2 = Fe21;

[0093] The first grille 2 corresponding to the noise reduction unit 10 at the air outlet is affected by the pressure generated by the cooling fan 50 and moves along the first guiding member 14. After balancing with the pressure generated by the cooling fan 50 under the action of the first elastic member 8, it stops. The cooling air flows out of the power cabin. At this time, the opening degree D1 of the flow-through opening between the first grille 2 and the second grille 3 is the opening degree 1, the thickness of the first chamber 5 becomes smaller, the thickness V1 of the first chamber 5 is V1 = V11, and the corresponding noise elimination frequency rises Fe1 = Fe11. At this time, the air flow rate M of the power cabin is 1;

[0094] Technical effect: At this time, the rotational speed of the fan 50 is in low-speed operation, and the opening degree of the flow port between the first grille 2 and the second grille 3 is in a small position, meeting the air volume requirement and helping to isolate the internal noise of the power cabin by the hood ventilation port; meanwhile, the noise frequency Fs1 generated by the engine and the fan is effectively absorbed by the noise elimination frequency Fe11 generated by the first chamber 5 and the noise elimination frequency Fe21 generated by the second chamber 6.

[0095] Condition 4: The engine is in normal operation, the rotational speed RpmFan of the fan 50 rises to gear 2, and the noise frequency Fs2 generated by the engine and the fan rises.

[0096] The second grille 3 corresponding to the noise reduction unit 10 at the air inlet is subjected to the negative pressure generated by the cooling fan 50, and further moves along the second guiding member 34 towards the fourth grille 4. After balancing with the negative pressure generated by the cooling fan 50 under the action of the second elastic member 9, it stops. The cooling air flows into the power cabin. At this time, the opening degree D2 of the flow port between the first grille 2 and the second grille 3 = opening degree 5, the thickness of the second chamber 6 further becomes smaller, the thickness V2 of the second chamber 6 = V22, and the corresponding noise elimination frequency Fe2 = Fe22;

[0097] The first grille 2 corresponding to the noise reduction unit 10 at the air outlet is subjected to the pressure generated by the cooling fan 50, and further moves along the first guiding member 14 towards the third grille 1. After balancing with the pressure generated by the cooling fan 50 under the action of the first elastic member 8, it stops. The cooling air flows out of the power cabin. At this time, the opening degree D1 of the flow port between the first grille 2 and the second grille 3 = opening degree 2, the thickness of the first chamber 5 further becomes smaller, the thickness V1 of the first chamber 5 = V12, and the corresponding noise elimination frequency rises Fe1 = Fe12. At this time, the air flow rate M of the power cabin = 2;

[0098] Technical effect: At this time, the fan rotational speed is in medium-speed operation, and the opening degree of the flow port between the first grille 2 and the second grille 3 is in the middle position, meeting the air volume requirement and helping to isolate the internal noise of the power cabin by the hood ventilation port; while the fan rotational speed rises, the noise frequency Fs2 rises. The decrease in the thickness V1 of the first chamber 5 at the air outlet brings an increase in the noise elimination frequency Fe12, and the decrease in the thickness V2 of the second chamber 6 at the air inlet brings an increase in the noise elimination frequency Fe22; while the noise frequency Fs2 generated by the engine and the fan changes, it is effectively absorbed by the noise elimination frequency Fe12 generated by the first chamber 5 and the noise elimination frequency Fe22 generated by the second chamber 6 synchronously.

[0099] Condition 5: The engine is in normal operation, the rotational speed RpmFan of the fan 50 further rises to gear 3, and the noise frequency Fs3 generated by the engine and the fan further rises.

[0100] The second grille 3 corresponding to the noise reduction unit 10 at the air inlet is subjected to the negative pressure generated by the cooling fan 50, and further moves along the second guiding member 34 towards the fourth grille 4. After balancing with the negative pressure generated by the cooling fan 50 under the action of the second elastic member 9, it stops. The cooling air flows into the engine compartment. At this time, the opening degree D2 of the flow port between the first grille 2 and the second grille 3 = the opening degree 6, the thickness of the second chamber 6 further decreases, the thickness V2 of the second chamber 6 = V23, and the corresponding noise reduction frequency Fe2 = Fe23;

[0101] The first grille 2 corresponding to the noise reduction unit 10 at the air outlet is subjected to the pressure generated by the cooling fan 50, and further moves along the first guiding member 14 towards the third grille 1. After balancing with the pressure generated by the cooling fan 50 under the action of the first elastic member 8, it stops. The cooling air flows out of the engine compartment. At this time, the opening degree D1 of the flow port between the first grille 2 and the second grille 3 = the opening degree 3, the thickness of the first chamber 5 further decreases, the thickness V1 of the first chamber 5 = V13, and the corresponding noise reduction frequency increases Fe1 = Fe13. At this time, the air flow rate M in the engine compartment = 3;

[0102] Technical effect: At this time, the fan speed is in high-speed operation, and the opening degree of the flow port between the first grille 2 and the second grille 3 is in a large position, meeting the air volume requirement; while the fan speed increases, the noise frequency Fs3 increases. The decrease in the thickness V1 of the first chamber 5 at the air outlet brings an increase in the noise reduction frequency Fe13, and the decrease in the thickness V2 of the second chamber 6 at the air inlet brings an increase in the noise reduction frequency Fe23; while the noise frequency Fs3 generated by the engine and the fan changes, it is effectively absorbed synchronously by the noise reduction frequency Fe13 generated by the first chamber 5 and the noise reduction frequency Fe23 generated by the second chamber 6.

[0103] Condition 6: The engine is in normal operation, the rotational speed RpmFan of the fan 50 is full speed, and the noise frequency Fs3 generated by the engine and the fan is the highest.

[0104] The second grille 3 corresponding to the noise reduction unit 10 at the air inlet is subjected to the negative pressure generated by the cooling fan 50, and further moves along the second guiding member 34 towards the fourth grille 4. After balancing with the negative pressure generated by the cooling fan 50 under the action of the second elastic member 9, it stops. The cooling air flows into the engine compartment. At this time, the opening degree D2 of the flow port between the first grille 2 and the second grille 3 = fully open, the thickness of the second chamber 6 further decreases, the thickness V2 of the second chamber 6 = V2min, and the corresponding noise reduction frequency is the highest Fe2 = Fe2max;

[0105] The first grille 2 corresponding to the noise reduction unit 10 of the air outlet is under the pressure generated by the cooling fan 50, and further moves along the first guiding member 14 towards the third grille 1, and stops after balancing with the pressure generated by the cooling fan 50 under the action of the first elastic member 8. The cooling air flows out of the engine compartment. At this time, the opening degree D1 of the flow port between the first grille 2 and the second grille 3 is fully open, the thickness of the first chamber 5 further becomes smaller, the thickness V1 of the first chamber 5 is V1min, and the corresponding maximum noise elimination frequency Fe1 is Fe13. At this time, the air flow rate M of the engine compartment is 4;

[0106] Technical effect: At this time, the fan speed is at full speed operation, the opening degree of the flow port between the first grille 2 and the second grille 3 is at the maximum position, meeting the air volume requirement; while the fan speed increases, the noise frequency Fs4 increases, the decrease in the thickness V1 of the first chamber 5 of the air outlet brings an increase in the maximum noise elimination frequency Fe1max, and the decrease in the thickness V2 of the second chamber 6 of the air inlet brings an increase in the maximum noise elimination frequency Fe2max; while the noise frequency Fs4 generated by the engine and the fan changes, it is effectively absorbed synchronously by the maximum noise elimination frequency Fe1max generated by the first chamber 5 and the maximum noise elimination frequency Fe2max generated by the second chamber 6.

[0107] Table 1 - Blowing fan working mode

[0108]

[0109] As Figure 9 shown, in some other embodiments, the fan 50 is a suction fan, the air outlet located at the end of the engine 60 far from the fan 50 is the air outlet, and the air inlet located at the end of the engine 60 adjacent to the fan 50 is the air inlet. In the noise reduction unit 10 installed on the air inlet, the fourth grille 4, the second grille 3, the first grille 2, and the third grille 1 are arranged from the inside to the outside and from the downstream to the upstream along the air flow direction inside the air outlet 30, as Figure 10 shown. In the noise reduction unit 10 installed on the air outlet, the fourth grille 4, the second grille 3, the first grille 2, and the third grille 1 are arranged from the inside to the outside and from the upstream to the downstream along the air flow direction inside the air outlet 30.

[0110] The following takes the fan 50 as a suction fan as an example in combination with Table 2 to introduce the various working conditions of the engine compartment of this embodiment:

[0111] Working condition 1: The engine is in a stopped state, the fan speed is 0, the noise reduction unit 10 is in the initial state. At this time, the air inlet and the air outlet are in a closed and non-ventilated state, and the air flow rate M of the engine compartment is 0;

[0112] Technical effect: It avoids problems such as external dust pollution of the inside of the engine compartment and blockage of the heat exchange module caused by long-term exposure.

[0113] Operating condition 2: The engine is in a cold start state, the water temperature is below 80 °C, generating a noise frequency Fs0. At this time, the fan speed is 0, the opening degree D1 of the flow port between the first grille 2 and the second grille 3 corresponding to the noise reduction unit 10 at the air inlet is 0, the thickness V2 of the second chamber 6 is V2 = V2max, which is in the maximum state, and the corresponding sound absorption frequency Fe2 = Fe2min is the lowest. The opening degree D2 of the flow port between the first grille 2 and the second grille 3 corresponding to the noise reduction unit 10 at the air outlet is 0, the thickness V1 of the first chamber 5 is V1 = V1max, which is in the maximum state, and the corresponding sound absorption frequency Fe1 = Fe1min is the lowest. At this time, the air inlet and the air outlet are in a sealed and non-ventilated state, and the air flow rate M in the power cabin is 0;

[0114] Technical effect: The sealed power cabin promotes the engine temperature to quickly rise to the normal operating temperature above 80 °C, improving the fuel economy of the engine and having a good sound insulation effect on the noise inside the engine hood; at the same time, the noise frequency Fs0 generated by the engine is effectively absorbed by the sound absorption frequency Fe1min generated by the first chamber 5 and the sound absorption frequency Fe2min generated by the second chamber 6.

[0115] Operating condition 3: The engine is in a normal operating state, and the rotational speed of the fan 50 is RpmFan = gear 1. The engine and the fan generate a noise frequency Fs1;

[0116] The second grille 3 corresponding to the noise reduction unit 10 at the air inlet is affected by the negative pressure generated by the cooling fan 50 and moves along the second guiding member 34 of the grid. After balancing with the negative pressure generated by the cooling fan 50 under the action of the second elastic member 9, it stops. The cooling air flows into the power cabin. At this time, the opening degree D1 of the flow port between the first grille 2 and the second grille 3 is D1 = opening degree 1, the thickness of the second chamber 6 becomes smaller, the thickness V2 of the second chamber 6 is V2 = V21, and the corresponding sound absorption frequency Fe2 = Fe21;

[0117] The first grille 2 corresponding to the noise reduction unit 10 at the air outlet is affected by the pressure generated by the cooling fan 50 and moves along the first guiding member 14 of the grid. After balancing with the pressure generated by the cooling fan 50 under the action of the first elastic member 8, it stops. The cooling air flows out of the power cabin. At this time, the opening degree D2 of the flow port between the first grille 2 and the second grille 3 is D2 = opening degree 4, the thickness of the first chamber 5 becomes smaller, the thickness V1 of the first chamber 5 is V1 = V11, and the corresponding sound absorption frequency increases to Fe1 = Fe11. At this time, the air flow rate M in the power cabin is 1;

[0118] Technical effect: At this time, the fan speed is in low-speed operation, and the opening degree of the flow port between the first grille 2 and the second grille 3 is in a small position, meeting the air volume requirement and helping the engine hood vent to isolate the internal noise of the power compartment; meanwhile, the noise frequency Fs1 generated by the engine 60 and the fan 50 is effectively absorbed by the noise elimination frequency Fe11 generated by the first chamber 5 and the noise elimination frequency Fe21 generated by the second chamber 6.

[0119] Condition 4: The engine is in normal operation, the rotation speed RpmFan of the fan 50 rises to gear 2, and the noise frequency Fs2 generated by the engine 60 and the fan 50 rises;

[0120] The second grille 3 corresponding to the noise reduction unit 10 at the air inlet is affected by the negative pressure generated by the cooling fan 50, and further moves along the second guiding member 34 towards the fourth grille 4. After balancing with the negative pressure generated by the cooling fan 50 under the action of the second elastic member 9, it stops. The cooling air flows into the power compartment. At this time, the opening degree D1 of the flow port between the first grille 2 and the second grille 3 = opening degree 2, the thickness of the second chamber 6 further becomes smaller, the thickness V2 of the second chamber 6 = V22, and the corresponding noise elimination frequency Fe2 = Fe22;

[0121] The first grille 2 corresponding to the noise reduction unit 10 at the air outlet is affected by the pressure generated by the cooling fan 50, and further moves along the first guiding member 14 towards the third grille 1. After balancing with the pressure generated by the cooling fan 50 under the action of the first elastic member 8, it stops. The cooling air flows out of the power compartment. At this time, the opening degree D2 of the flow port between the first grille 2 and the second grille 3 = opening degree 5, the thickness of the first chamber 5 further becomes smaller, the thickness V1 of the first chamber 5 = V12, and the corresponding noise elimination frequency rises Fe1 = Fe12. At this time, the air flow rate M of the power compartment = 2;

[0122] Technical effect: At this time, the fan speed is in medium-speed operation, and the opening degree of the flow port between the first grille 2 and the second grille 3 is in the middle position, meeting the air volume requirement and helping the engine hood vent to isolate the internal noise of the power compartment; while the fan speed rises, the noise frequency Fs2 rises. The decrease in the thickness V2 of the second chamber 6 at the air inlet brings an increase in the noise elimination frequency Fe22, and the decrease in the thickness V1 of the first chamber 5 at the air outlet brings an increase in the noise elimination frequency Fe12; while the noise frequency Fs2 generated by the engine and the fan changes, it is effectively absorbed by the noise elimination frequency Fe12 generated by the first chamber 5 and the noise elimination frequency Fe22 generated by the second chamber 6 synchronously.

[0123] Condition 5: The engine is in normal operation, the rotation speed RpmFan of the fan 50 further rises to gear 3, and the noise frequency Fs3 generated by the engine and the fan further rises;

[0124] The second grille 3 corresponding to the noise reduction unit 10 at the air inlet is under the negative pressure generated by the cooling fan 50, and further moves along the second guiding member 34 towards the fourth grille 4. After balancing with the negative pressure generated by the cooling fan 50 under the action of the second elastic member 9, it stops. The cooling air flows into the engine compartment. At this time, the opening degree D1 of the flow port between the first grille 2 and the second grille 3 = the opening degree 3, the thickness of the second chamber 6 further decreases, the thickness V2 of the second chamber 6 = V23, and the corresponding noise elimination frequency Fe2 = Fe23;

[0125] The first grille 2 corresponding to the noise reduction unit 10 at the air outlet is under the pressure generated by the cooling fan 50, and further moves along the first guiding member 14 towards the third grille 1. After balancing with the pressure generated by the cooling fan 50 under the action of the first elastic member 8, it stops. The cooling air flows out of the engine compartment. At this time, the opening degree D2 of the flow port between the first grille 2 and the second grille 3 = the opening degree 6, the thickness of the first chamber 5 further decreases, the thickness V1 of the first chamber 5 = V13, and the corresponding noise elimination frequency increases Fe1 = Fe13. At this time, the air flow rate M of the engine compartment = 3;

[0126] Technical effect: At this time, the fan speed is in high-speed operation, and the opening degree of the flow port between the first grille 2 and the second grille 3 is in a large position, meeting the air volume requirement; while the fan speed increases, the noise frequency Fs3 increases. The decrease in the thickness V3 of the second chamber 6 at the air inlet brings an increase in the noise elimination frequency Fe23, and the decrease in the thickness V1 of the first chamber 5 at the air outlet brings an increase in the noise elimination frequency Fe13; while the noise frequency Fs3 generated by the engine and the fan changes, it is effectively absorbed synchronously by the noise elimination frequency Fe13 generated by the first chamber 5 and the noise elimination frequency Fe23 generated by the second chamber 6.

[0127] Condition 6: The engine is in a normal operating state, the rotational speed RpmFan of the fan 50 is full speed, and the noise frequency Fs3 generated by the engine and the fan is the highest;

[0128] The second grille 3 corresponding to the noise reduction unit 10 at the air inlet is under the negative pressure generated by the cooling fan 50, and further moves along the second guiding member 34 towards the fourth grille 4. After balancing with the negative pressure generated by the cooling fan 50 under the action of the second elastic member 9, it stops. The cooling air flows into the engine compartment. At this time, the opening degree D1 of the flow port between the first grille 2 and the second grille 3 = fully open, the thickness of the second chamber 6 further decreases, the thickness V2 of the second chamber 6 = V2min, and the corresponding noise elimination frequency is the highest Fe2 = Fe2max;

[0129] The first grille 2 corresponding to the noise reduction unit 10 of the air outlet is subjected to the pressure generated by the cooling fan 50, and further moves along the first guiding member 14 towards the third grille 1. After balancing with the pressure generated by the cooling fan 50 under the action of the first elastic member 8, it stops. The cooling air flows out of the power cabin. At this time, the opening degree D2 of the flow port between the first grille 2 and the second grille 3 is fully open, the thickness of the first chamber 5 further becomes smaller, the thickness V1 of the first chamber 5 is V1min, and the corresponding maximum noise reduction frequency Fe1 is Fe13. At this time, the air flow rate M of the power cabin is 4;

[0130] Technical effect: At this time, the fan speed is at full speed operation, the opening degree of the flow port between the first grille 2 and the second grille 3 is at the maximum position, meeting the air volume requirement; while the fan speed increases, the noise frequency Fs4 increases, the thickness V2 of the second chamber 6 at the air inlet becomes smaller, resulting in an increase in the maximum noise reduction frequency Fe2max, and the thickness V1 of the first chamber 5 at the air outlet becomes smaller, resulting in an increase in the maximum noise reduction frequency Fe1max; while the noise frequency Fs4 generated by the engine and the fan changes, it is effectively absorbed synchronously by the maximum noise reduction frequency Fe1max generated by the first chamber 5 and the maximum noise reduction frequency Fe2max generated by the second chamber 6.

[0131] Table 2 - Working mode of the air - suction fan

[0132]

[0133]

[0134] The above are only exemplary embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A power cabin, characterized in that, Comprising: A compartment (20); An engine (60), disposed within the compartment (20) and having a coolant flow path through which coolant circulates; A radiator (40), disposed within the compartment (20) and communicating with the coolant flow path of the engine (60); A vent (30), disposed on the compartment (20) and for introducing air that exchanges heat with the radiator (40) or discharging air that has exchanged heat with the radiator (40); And A noise reduction unit (10), disposed on the vent (30), the noise reduction unit (10) including a first grille (2), a second grille (3) that is stacked with the first grille (2) in the thickness direction of the wall of the compartment (20) and has an adjustable spacing from the first grille (2), and a first elastic member (8) that pushes the first grille (2) toward the second grille (3). The first grille (2) includes a plurality of first air vents (21) arranged side by side and a first solid portion (22) located between two adjacent first air vents (21). The second grille (3) includes a plurality of second air vents (31) arranged side by side and a second solid portion (32) located between two adjacent second air vents (31). The projection of the second air vent (31) in a plane perpendicular to the thickness direction partially or completely overlaps the projection of the first solid portion (22) in the plane, so that the air flowing out of the second air vent (31) drives the first grille (2) in a direction away from the second grille (3).

2. The power cabin according to claim 1, characterized in that, It further includes a third grille (1) disposed on a side of the first grille (2) away from the second grille (3). The third grille (1) includes a plurality of third air vents (11) arranged side by side and a third solid portion (12) located between two adjacent third air vents (11). The projection of the third solid portion (12) and the first solid portion (22) in the plane partially or completely overlaps. The power compartment further includes a first shielding member (7). The first shielding member (7) extends around the edge of the first solid portion (22) to enclose a first chamber (5) with the first solid portion (22) and the third solid portion (12). A plurality of first through holes (23) communicating with the first chamber (5) are provided on the first solid portion (22) to form a perforated panel resonance sound absorption structure.

3. The power cabin according to claim 2, wherein The first shielding member (7) includes a flexible member. One end of the flexible member is connected to the first solid portion (22), and the other end is connected to the third solid portion (12).

4. The power cabin according to claim 2, characterized in that, The projection of the third air vent (11) and the first air vent (21) in the plane partially or completely overlaps.

5. The power cabin according to claim 2, characterized in that, The first elastic member (8) is disposed between the first grille (2) and the third grille (1). One end of the first elastic member (8) abuts against the first grille (2), and the other end abuts against the third grille to push the first grille (2) toward the second grille (3).

6. The power compartment according to claim 2, wherein The second grille (3), the first grille (2), and the third grille (1) are arranged in sequence from upstream to downstream along the air flow direction in the air vent (30); or The second grille (3), the first grille (2), and the third grille (1) are arranged in sequence from downstream to upstream along the air flow direction in the air vent (30).

7. The power cabin according to claim 2, wherein the first grille (2) is installed in the air vent (30) and is configured to be slidable relative to the cabin (20) in the thickness direction to adjust the spacing between the first grille (2) and the second grille (3); and / or the third grille (1) is fixedly installed in the air vent (30).

8. The power cabin according to any one of claims 1 to 7, characterized in that, It further includes a fourth grille (4) provided on a side of the second grille (3) away from the first grille (2). The fourth grille (4) includes a plurality of fourth air vents (41) arranged side by side and a fourth solid part (42) located between two adjacent fourth air vents (41). The projection of the fourth solid part (42) in the plane partially or completely overlaps with the projection of the second solid part (32).

9. The power cabin according to claim 8, wherein the projection of the fourth air vent (41) and the second air vent (31) in the plane partially or completely overlaps; and / or the projection of the first air vent (21) and the second solid part (32) in the plane partially or completely overlaps.

10. The power cabin according to claim 8, wherein the second grille (3) is installed in the air vent (30) and is configured to be slidable relative to the cabin (20) in the thickness direction to adjust the spacing between the first grille (2) and the second grille (3); and / or the fourth grille (4) is fixedly installed in the air vent (30).

11. The power cabin according to claim 10, characterized in that, It further includes a second elastic member (9) that pushes the second grille (3) toward the first grille (2). The second elastic member (9) is provided between the second grille (3) and the fourth grille (4).

12. The power cabin according to claim 8, characterized in that, It further includes a second shielding member (35) that extends around the edge of the second solid part (32) to enclose a second chamber (6) with the second solid part (32) and the fourth solid part (42). A second through hole (43) communicating with the second chamber (6) is provided on the fourth solid part (42) to form a perforated panel resonance sound absorption structure.

13. The power cabin according to claim 12, characterized in that, The second shielding member (35) includes a first plate-like member (351) and a second plate-like member (352) erected between the second grille (3) and the fourth grille (4), the first plate-like member (351) and the second plate-like member (352) are respectively fixedly connected to both sides of the second solid part (32). The fourth solid part (42) is located between the first plate-like member (351) and the second plate-like member (352) and can slide relative to the first plate-like member (351) and the second plate-like member (352) in the thickness direction; or The first plate-shaped member (351) and the second plate-shaped member (352) are respectively fixedly connected to both sides of the fourth solid portion (42), and the second solid portion (32) is located between the first plate-shaped member (351) and the second plate-shaped member (352) and can slide relative to the first plate-shaped member (351) and the second plate-shaped member (352) along the thickness direction.

14. The power cabin according to claim 8, wherein the fourth grille (4), the second grille (3), and the first grille (2) are arranged in sequence from upstream to downstream along the air flow direction in the ventilation opening (30); or the fourth grille (4), the second grille (3), and the first grille (2) are arranged in sequence from downstream to upstream along the air flow direction in the ventilation opening (30).

15. An engineering machinery, characterized in that, Comprising the power cabin according to any one of claims 1 to 14.

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