A front lower guard assembly

Abstract

This utility model relates to the field of automotive chassis technology, and more particularly to a front underbody protection plate assembly, including an engine underbody protection plate, a front bumper underbody protection plate, and an air guide device. The engine underbody protection plate and the front bumper underbody protection plate are connected as one unit. The engine underbody protection plate includes a first connecting portion disposed at the front end of the engine underbody protection plate. The front bumper underbody protection plate includes a second connecting portion disposed at the rear end of the front bumper underbody protection plate. The engine underbody protection plate and the front bumper underbody protection plate are installed and fixed through the first connecting portion and the second connecting portion. The air guide device is used to guide the airflow generated during vehicle driving to the top of the engine underbody protection plate.

Description

Technical Field

[0001] This utility model relates to the field of automotive chassis technology, and in particular to a front lower guard plate assembly. Background Technology

[0002] Various skid plates are typically installed under the engine compartment and the lower part of the front bumper assembly to protect important components in the front of the engine compartment, such as the engine oil pan. They also reduce wind resistance to lower overall fuel consumption. Furthermore, due to the high temperature in the engine compartment, the skid plates located below it usually need to support heat dissipation. Currently, common engine underbody skid plates and front bumper underbody skid plates generally suffer from poor wind resistance reduction capabilities and installation difficulties. Utility Model Content

[0003] This utility model provides a front underbody skid plate assembly that can reduce wind resistance and is easy to assemble, including an engine underbody skid plate, a front bumper underbody skid plate, and an air guide device. The engine underbody skid plate and the front bumper underbody skid plate are connected as one unit. The engine underbody skid plate includes a first connecting part located at the front end of the engine underbody skid plate. The front bumper underbody skid plate includes a second connecting part located at the rear end of the front bumper underbody skid plate. The engine underbody skid plate and the front bumper underbody skid plate are installed and fixed through the first connecting part and the second connecting part. The air guide device is used to guide the airflow generated during vehicle driving to the top of the engine underbody skid plate.

[0004] Furthermore, the first connecting part includes a mounting boss, which protrudes upward from the surface of the engine underbody protection plate. A plurality of mounting bosses are spaced apart along the width direction of the vehicle body at the front of the engine underbody protection plate. A bolt hole is provided in the center of the mounting boss for bolts to pass through. The first connecting part is connected and fixed to the second connecting part and the front bumper beam through the mounting boss and the bolts passing through it.

[0005] Furthermore, the first connecting portion includes a positioning portion, which is formed by the front end of the engine underbody protection plate protruding forward. A plurality of the positioning portions are spaced apart along the width direction of the vehicle body at the front end of the engine underbody protection plate. The positioning portions can extend into the second connecting portion at the rear end of the front bumper underbody protection plate to position the first connecting portion and the second connecting portion relative to each other.

[0006] Furthermore, the positioning part includes a reinforcing rib, which protrudes upward from the surface of the positioning part, and the reinforcing rib is used to improve the structural strength of the positioning part.

[0007] Furthermore, the second connecting part also includes a positioning boss, which is formed by the upward protrusion of the surface of the front bumper lower guard plate. Several positioning bosses are spaced apart along the width direction of the vehicle body at the front of the front bumper lower guard plate. A bolt hole is provided in the center of the positioning boss for the bolt to pass through. The second connecting part is connected and fixed to the first connecting part and the front bumper crossbeam through the positioning boss and the bolt passing through it.

[0008] Furthermore, the second connecting portion includes positioning slots, and a plurality of positioning slots are spaced apart on the second connecting portion along the width direction of the vehicle body. The positioning slots can accommodate the positioning portions extending therein, thereby positioning the first connecting portion and the second connecting portion relative to each other.

[0009] Furthermore, the second connecting portion includes a first stepped surface, a second stepped surface, and a transition surface. The first stepped surface is located below the second stepped surface in the vehicle height direction. The transition surface connects the first stepped surface and the second stepped surface, and the positioning slot is provided on the transition surface.

[0010] Furthermore, the air guiding device includes an air inlet, a windward section, and an air outlet. The windward section is disposed on the engine underbody protection plate. The air inlet is a through hole opened on the engine underbody protection plate. The air outlet is opened at the rear end of the windward section. The windward section partially covers the top of the air inlet. The airflow generated during vehicle operation can enter the windward section from below the engine underbody protection plate through the air inlet, collide with the windward section, and flow to the air outlet under the guidance of the windward section, and then flow to the top of the engine underbody protection plate from the air outlet.

[0011] Furthermore, the positioning slot also includes a clearance opening located on the second step surface. The clearance opening is located at the connection between the second step surface and the transition surface, and the open space at the front of the clearance opening is connected to the open space at the top of the positioning slot as a whole.

[0012] Furthermore, the air guiding device includes a first air guiding section and a second air guiding section. Both the first air guiding section and the second air guiding section include the air inlet, the windward section, and the air outlet. The first air guiding section is located on the left side of the engine underbody protection plate, and the second air guiding section is located in the middle of the engine underbody protection plate.

[0013] The front lower guard plate assembly provided by this utility model connects and positions the engine underguard and the front bumper underguard as a single unit through a first connecting part and a second connecting part. A wind-guiding device reduces wind resistance and lifting force, thereby improving vehicle stability and handling. Furthermore, this utility model simplifies the relative positioning of the front bumper underguard and the engine underguard through a positioning part on the first connecting part and a positioning slot on the second connecting part, reducing assembly difficulty and time, and effectively improving production efficiency. Attached Figure Description

[0014] Figure 1 A schematic diagram of the front lower guard plate assembly provided by this utility model.

[0015] Figure 2 This is a top view of the engine underbody protection plate in this utility model.

[0016] Figure 3 This is a bottom view of the engine underbody protection plate in this utility model.

[0017] Figure 4 This is a schematic diagram of the first mounting part in this utility model.

[0018] Figure 5 This is a schematic diagram of the first-order surface, the second-order surface, and the transition surface in this utility model.

[0019] Figure 6 This is a schematic diagram of the air guiding device in this utility model.

[0020] In the picture: 1. Engine underbody protection plate; 2. Front bumper lower protection plate; 3. First connecting part; 31. Mounting boss; 31a. First boss; 31b. Second boss; 31c. Third boss; 31d. Fourth boss; 31e. Fifth boss; 32. Positioning part; 321. Reinforcing rib; 4. Second connecting part; 401. First stepped surface; 402. Second stepped surface; 403. Transition surface; 41. Positioning boss; 41a. Sixth boss; 41b. Seventh boss; 41c. Eighth boss; 41d. Ninth boss; 41e. Tenth boss; 42. Positioning slot; 421. Clearance opening; 5. Air guide device; 51. Air inlet; 52. Windward part; 53. Air outlet; 5a. First air guide part; 5b. Second air guide part. Detailed Implementation

[0021] To further illustrate the technical means and effects adopted by this utility model in order to achieve the intended utility model purpose, the present utility model will be described in detail below with reference to the accompanying drawings and preferred embodiments.

[0022] It should be noted that the terms "first," "second," "third," "fourth," etc., in the specification and claims of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0023] In this manual, the directional terms "X-direction," "Y-direction," and "Z-direction" refer to the "vehicle X-direction," "vehicle Y-direction," and "vehicle Z-direction" commonly used in the automotive industry, respectively. "Vehicle X-direction" refers to the length of the vehicle body, which is also the front-to-back direction; "Vehicle Y-direction" refers to the width of the vehicle body, which is also the left-to-right direction; and "Vehicle Z-direction" refers to the height of the vehicle body, which is also the up-and-down direction.

[0024] Please see Figure 1 The front lower guard plate assembly of this utility model includes an engine underbody guard plate 1, a front bumper lower guard plate 2, and an air guide device 5. The engine underbody guard plate 1 and the front bumper lower guard plate 2 are connected as one unit. The engine underbody guard plate 1 includes a first connecting part 3, which is disposed at the front end of the engine underbody guard plate 1. The front bumper lower guard plate 2 includes a second connecting part 4, which is disposed at the rear end of the front bumper lower guard plate 2. The engine underbody guard plate 1 and the front bumper lower guard plate 2 are installed and fixed through the first connecting part 3 and the second connecting part 4. The air guide device 5 is used to guide the airflow generated during vehicle driving to the top of the engine underbody guard plate 1. Specifically, in one embodiment of this utility model, the engine underbody protection plate 1 is located in front of the driver's compartment and below the engine compartment, and the front bumper lower protection plate 2 is located in front of the engine compartment and below the front bumper. The engine underbody protection plate 1 and the front bumper lower protection plate 2 are connected as one unit through a first connecting part 3 and a second connecting part 4. The first connecting part 3 and the second connecting part 4 are also connected as one unit to the front bumper crossbeam located above. The air guide device 5 is located in the middle of the engine underbody protection plate 1 in the length direction of the vehicle body, so it can guide the airflow generated during vehicle driving, more specifically, the airflow flowing from below the front bumper lower protection plate 2 to the lower front part of the engine underbody protection plate 1, to the upper rear part of the engine underbody protection plate 1 and near the front bulkhead. This utility model positions and connects the engine underbody protection plate 1 and the front bumper lower protection plate 2 as one unit through the first connecting part 3 and the second connecting part 4, and reduces wind resistance and lift force through the air guide device 5, thereby improving the stability and handling of the vehicle.

[0025] Please refer to the following: Figure 2As shown in Figure 4, the first connecting part 3 of this utility model further includes a mounting boss 31, which is formed by the upward protrusion of the surface of the engine underbody plate 1. Several mounting bosses 31 are spaced apart along the width direction of the vehicle body at the front of the engine underbody plate 1. A bolt hole for bolts to pass through is provided in the center of the mounting boss 31. The first connecting part 3 is connected and fixed to the second connecting part 4 and the front bumper beam through the mounting boss 31 and the bolts passing through it. Specifically, in one embodiment of this utility model, the mounting boss 31 is a frustum-shaped protrusion structure protruding from the upper surface of the engine underbody guard plate 1; the mounting boss 31 includes a first boss 31a, a second boss 31b, a third boss 31c, a fourth boss 31d, and a fifth boss 31e arranged sequentially at intervals in the vehicle width direction. The first boss 31a is located on the right side of the left fender in the vehicle width direction, the fifth boss 31e is located on the left side of the right fender in the vehicle width direction, the third boss 31c is located in the middle of the vehicle body in the vehicle width direction, the second boss 31b is disposed between the first boss 31a and the third boss 31c in the vehicle width direction, and the fourth boss 31d is located between the third boss 31c and the fifth boss 31e in the vehicle width direction.

[0026] Furthermore, the first connecting part 3 in this utility model also includes a positioning part 32, which is formed by the front end of the engine underbody protection plate 1 protruding forward. Several positioning parts 32 are spaced apart along the width direction of the vehicle body at the front end of the engine underbody protection plate 1. The positioning parts 32 can extend into the second connecting part 4 at the rear end of the front bumper underbody protection plate 2, thereby positioning the first connecting part 3 and the second connecting part 4 relative to each other. Specifically, in one embodiment of this utility model, the positioning part 32 is a tongue structure that protrudes forward along the length direction of the vehicle body from the front end of the engine underbody protection plate 1. The positioning part 32 includes a first tongue 32a, a second tongue, and a third tongue arranged sequentially at intervals along the width direction of the vehicle body. The first tongue 32a is located between the first boss 31a and the second boss 31b in the width direction of the vehicle body. The second tongue is located in the middle of the vehicle body in the width direction of the vehicle body. The third tongue is located between the fourth boss 31d and the fifth boss 31e in the width direction of the vehicle body. The first tongue 32a, the second tongue, and the third tongue are also provided with reinforcing ribs 321. The reinforcing ribs 321 are formed by protruding upward from the surface of the positioning part 32. The reinforcing ribs 321 are used to improve the structural strength of the positioning part 32.

[0027] Please refer to the following: Figure 5Furthermore, the second connecting part 4 in this utility model includes a first stepped surface 401, a second stepped surface 402, and a transition surface 403. The first stepped surface 401 is located below the second stepped surface 402 in the vehicle height direction. The transition surface 403 connects the first stepped surface 401 and the second stepped surface 402. The second stepped surface 402 is provided with a positioning boss 41 for matching with the mounting boss 31. The transition surface 403 is provided with a positioning slot 42 for accommodating the positioning part 32. Specifically, in one embodiment of this utility model, the first step surface 401 and the second step surface 402 are both parallel to the XY plane of the vehicle body. The transition surface 403 is arranged vertically to the first step surface 401 and the second step surface 402. The first step surface 401 is located below the engine underbody protection plate 1, and the second step surface 402 is located above the engine underbody protection plate 1. The transition surface 403 connects the first step surface 401 and the second step surface 402 along the height direction of the vehicle body. The second step surface 402 extends from the top of the transition surface 403 towards the rear of the vehicle body. That is, the first step surface 401, the transition surface 403, and... The second-level surface 402 is connected in a "Z" shape; the positioning boss 41 is formed by protruding upward from the surface of the second-level surface 402, and the mounting boss 31 abuts against the positioning boss 41 from below the second-level surface 402. Several positioning bosses 41 are spaced apart along the width of the vehicle body at the rear of the front bumper lower guard plate 2. The center of the positioning boss 41 is provided with a bolt hole through which a bolt can pass. Several positioning slots 42 are spaced apart along the width of the vehicle body on the transition surface 403. The positioning slots 42 can accommodate the positioning part 32 that extends into them, thereby positioning the first connecting part 3 and the second connecting part 4 relative to each other.

[0028] In one embodiment of this utility model, a positioning boss 41 protrudes from the second step surface 402. The positioning boss 41 includes a sixth boss 41a, a seventh boss 41b, an eighth boss 41c, a ninth boss 41d, and a tenth boss 41e arranged sequentially at intervals in the vehicle width direction. These bosses abut against the first boss 31a, the second boss 31b, the third boss 31c, the fourth boss 31d, and the fifth boss 31e located above them, respectively. The sixth boss 41a is located to the right of the left fender in the vehicle width direction and above the first boss 31a in the vehicle height direction. The tenth boss 41a... e is located to the left of the right fender in the width direction and above the fifth boss 31e in the height direction. The eighth boss 41c is located in the middle of the vehicle body in the width direction and above the third boss 31c in the height direction. The seventh boss 41b is located between the sixth boss 41a and the eighth boss 41c in the width direction and above the second boss 31b in the height direction. The ninth boss 41d is located between the eighth boss 41c and the tenth boss 41e in the width direction and above the fourth boss 31d in the height direction. Specifically, in this embodiment, the sixth boss 41a, the eighth boss 41c, and the tenth boss 41e are frustum-shaped protrusions with the same shape as the first boss 31a, the second boss 31b, the third boss 31c, the fourth boss 31d, and the fifth boss 31e. The seventh boss 41b and the ninth boss 41d are square frustum-shaped protrusions with slightly larger areas. This is based on the sheet metal space allowance near the front lower guard plate 2. The larger seventh boss 41b and the ninth boss 41d have greater connection rigidity with the lower second boss 31b and the fourth boss 31d. The sixth boss 41a, the eighth boss 41c, and the tenth boss 41e are set as smaller frustum-shaped protrusions to avoid other sheet metal parts. It is readily understood that in other embodiments of this utility model, the sixth boss 41a, the eighth boss 41c, and the tenth boss 41e may also be configured as larger square platform-shaped protrusions based on the sheet metal space allowance near the front lower guard plate 2.

[0029] In one embodiment of this utility model, the positioning slot 42 is a flat through hole formed on the transition surface 403. The positioning slot 42 includes a first through hole, a second through hole, and a third through hole arranged sequentially at intervals in the vehicle width direction. The first through hole is located between the sixth boss 41a and the seventh boss 41b in the vehicle width direction, the second through hole is located in the middle of the vehicle body in the vehicle width direction, and the third through hole is located between the ninth boss 41d and the tenth boss 41e in the vehicle width direction. It is easy to understand that the positions of the first through hole, the second through hole, and the third through hole on the front bumper lower guard plate 2 correspond to the positions of the first tongue 32a, the second tongue 32b, and the third tongue 32c on the engine underbody guard plate 1. The first tongue 32a, the second tongue 32b, and the third tongue 32c are respectively used to extend into the first through hole, the second through hole, and the third through hole along the length direction of the vehicle body. When assembling the front bumper under guard plate 2 and the engine under guard plate 1 on the production line, the front bumper under guard plate 2 and the engine under guard plate 1 can be easily positioned relative to each other by the positioning part 32 on the first connecting part 3 and the positioning slot 42 on the second connecting part 4, which reduces the assembly difficulty and time and effectively improves production efficiency.

[0030] In another embodiment of this utility model, the positioning slot 42 further includes a clearance opening 421 located on the second stepped surface 402. The clearance opening 421 is located at the connection between the second stepped surface 402 and the transition surface 403, and the front part of the clearance opening 421 is integrally connected with the upper part of the positioning slot 42. The clearance opening 421 is provided to avoid the reinforcing rib 321 protruding on the positioning part 32, preventing the second stepped surface 402 from rubbing against the reinforcing rib 321 in the vehicle height direction, thus affecting the smoothness of assembly.

[0031] Please refer to the following: Figure 6Furthermore, the air guiding device 5 in this utility model includes an air inlet 51, a windward section 52, and an air outlet 53. The windward section 52 is disposed on the engine underbody protection plate 1, the air inlet 51 is opened on the engine underbody protection plate 1, and the air outlet 53 is opened at the rear end of the windward section 52. The windward section 52 partially covers the top of the air inlet 51. The airflow generated during vehicle operation can enter the windward section 52 from below the engine underbody protection plate 1 through the air inlet 51, and after colliding with the windward section 52, it flows to the air outlet 53 under the guidance of the windward section 52, and then flows to the top of the engine underbody protection plate 1 from the air outlet 53. Specifically, in one embodiment of this utility model, the windward portion 52 is a flat shell-shaped structure protruding above the engine underbody 1. The size of the windward portion 52 gradually increases from front to back in the width direction of the vehicle body, and the size of the windward portion 52 also gradually increases from front to back in the height direction of the vehicle body. The projections of the windward portion 52 on the XY plane and the XZ plane of the vehicle body are approximately triangular in shape with a small front end and a large rear end. The windward portion 52 configured in this way can more effectively reduce wind resistance. The air inlet 51 is a through hole opened on the engine underbody protection plate 1. The projection shape of the air inlet 51 in the XY direction of the vehicle body is similar to the projection shape of the windward part 52 in the XY section of the vehicle body, and the projection of the air inlet 51 in the XY direction of the vehicle body is larger than the projection of the windward part 52 in the XY direction of the vehicle body. The air outlet 53 is also located within the projection range of the air inlet 51 in the XY direction of the vehicle body in the length direction of the vehicle body. That is, the rear part of the windward part 52 is open relative to the space below the engine underbody protection plate 1. The airflow generated during vehicle driving can also flow directly from the air inlet 51 to the air outlet 53. The air guide device 5 with such a configuration can maintain downforce when the air volume is large, and improve driving stability.

[0032] In one embodiment of the present invention, the air guiding device 5 includes a first air guiding part 5a and a second air guiding part 5b. Both the first air guiding part 5a and the second air guiding part 5b include an air inlet 51, a windward part 52 and an air outlet 53. The first air guiding part 5a is located on the left side of the engine underbody protection plate 1 in the vehicle width direction and in front of the engine underbody protection plate 1 and behind the first connecting part 3 in the vehicle length direction. The second air guiding part 5b is located in the middle of the engine underbody protection plate 1 in the vehicle width direction and in the middle of the engine underbody protection plate 1 in the vehicle length direction. The size of the first air guide 5a is larger than that of the second air guide 5b. This is based on the sheet metal space allowance near the engine underbody protection plate 1. Larger and more numerous flat shell-like structures will give the engine underbody protection plate 1 a stronger effect in reducing wind resistance. However, when setting the air guide device 5 on the engine underbody protection plate 1, the space occupied by other components must also be considered. Therefore, the larger first air guide 5a is set in a relatively open sheet metal area on the engine underbody protection plate 1, while the size of the second air guide 5b, located in the middle of the engine underbody protection plate 1, is set to be smaller. It is easy to understand that in other embodiments of this utility model, the position and size of the first air guide 5a and the second air guide 5b can also be set according to the sheet metal space allowance near the engine underbody protection plate 1.

[0033] In summary, the front lower guard plate assembly of this utility model connects and positions the engine underbody guard plate 1 and the front bumper underbody guard plate 2 as a single unit via the first connecting part 3 and the second connecting part 4. The air guide device 5 reduces wind resistance and lifting force, thereby improving vehicle stability and handling. Furthermore, this utility model simplifies the relative positioning of the front bumper underbody guard plate 2 and the engine underbody guard plate 1 via the positioning part 32 on the first connecting part 3 and the positioning slot 42 on the second connecting part 4, reducing assembly difficulty and time, and effectively improving production efficiency.

[0034] The above are merely specific embodiments of this utility model, but the protection scope of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the scope of the claims.

Claims

1. A front lower guard plate assembly, characterized in that: The system includes an engine underbody guard (1), a front bumper lower guard (2), and an air guide device (5). The engine underbody guard (1) and the front bumper lower guard (2) are connected as one unit. The engine underbody guard (1) includes a first connecting part (3) which is located at the front end of the engine underbody guard (1). The front bumper lower guard (2) includes a second connecting part (4) which is located at the rear end of the front bumper lower guard (2). The engine underbody guard (1) and the front bumper lower guard (2) are installed and fixed through the first connecting part (3) and the second connecting part (4). The air guide device (5) is used to guide the airflow generated during vehicle operation to the top of the engine underbody guard (1).

2. The front lower guard plate assembly as described in claim 1, characterized in that: The first connecting part (3) includes a mounting boss (31), which is formed by the upward protrusion of the surface of the engine underbody plate (1). Several mounting bosses (31) are spaced apart along the width direction of the vehicle body at the front of the engine underbody plate (1). A bolt hole is provided in the center of the mounting boss (31) for bolts to pass through. The first connecting part (3) is connected and fixed to the second connecting part (4) and the front bumper beam through the mounting boss (31) and the bolts passing through it.

3. The front lower guard plate assembly as described in claim 1, characterized in that: The first connecting part (3) includes a positioning part (32), which is formed by the front end of the engine underbody protection plate (1) protruding forward. A plurality of positioning parts (32) are spaced apart along the width direction of the vehicle body at the front end of the engine underbody protection plate (1). The positioning part (32) can extend into the second connecting part (4) at the rear end of the front bumper underbody protection plate (2) to position the first connecting part (3) and the second connecting part (4) relative to each other.

4. The front lower guard plate assembly as described in claim 3, characterized in that: The positioning part (32) includes a reinforcing rib (321), which is formed by the upward protrusion of the surface of the positioning part (32). The reinforcing rib (321) is used to improve the structural strength of the positioning part (32).

5. The front lower guard plate assembly as described in claim 2, characterized in that: The second connecting part (4) further includes a positioning boss (41), which is formed by the upward protrusion of the surface of the front bumper lower guard plate (2). Several positioning bosses (41) are spaced apart along the width direction of the vehicle body at the front of the front bumper lower guard plate (2). A bolt hole is provided in the center of the positioning boss (41) for the bolt to pass through. The second connecting part (4) is connected and fixed to the first connecting part (3) and the front bumper crossbeam through the positioning boss (41) and the bolt passing through it.

6. The front lower guard plate assembly as described in claim 3, characterized in that: The second connecting part (4) includes a positioning slot (42), and a plurality of the positioning slots (42) are spaced apart on the second connecting part (4) along the width direction of the vehicle body. The positioning slots (42) can accommodate the positioning part (32) extending into them, and position the first connecting part (3) and the second connecting part (4) relative to each other.

7. The front lower guard plate assembly as described in claim 6, characterized in that: The second connecting part (4) includes a first stepped surface (401), a second stepped surface (402) and a transition surface (403). The first stepped surface (401) is located below the second stepped surface (402) in the vehicle height direction. The transition surface (403) connects the first stepped surface (401) and the second stepped surface (402). The positioning slot (42) is provided on the transition surface (403).

8. The front lower guard plate assembly as described in claim 7, characterized in that: The air guide device (5) includes an air inlet (51), a windward section (52), and an air outlet (53). The windward section (52) is disposed on the engine underbody plate (1). The air inlet (51) is a through hole opened on the engine underbody plate (1). The air outlet (53) is opened at the rear end of the windward section (52). The windward section (52) partially covers the top of the air inlet (51). The airflow generated during vehicle operation can enter the windward section (52) from below the engine underbody plate (1) through the air inlet (51), and after colliding with the windward section (52), it flows to the air outlet (53) under the guidance of the windward section (52), and then flows to the top of the engine underbody plate (1) from the air outlet (53).

9. The front lower guard plate assembly as described in claim 7, characterized in that: The positioning slot (42) also includes a clearance opening (421) on the second step surface (402). The clearance opening (421) is located at the connection between the second step surface (402) and the transition surface (403). The open space at the front of the clearance opening (421) is connected to the open space at the top of the positioning slot (42) as a whole.

10. The front lower guard plate assembly as described in claim 8, characterized in that: The air guide device (5) includes a first air guide section (5a) and a second air guide section (5b). Both the first air guide section (5a) and the second air guide section (5b) include the air inlet (51), the windward section (52) and the air outlet (53). The first air guide section (5a) is located on the left side of the engine underbody plate (1), and the second air guide section (5b) is located in the middle of the engine underbody plate (1).

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