In the following description, the term "comprising" is a synonym of "comprising", and is not limited to, other elements can be present in the vehicle or under-bottom plates related to the term. The term "includes" comprising the term "consisting of ...". The term "under", "upper", "front", "post" is understood relative to the usual orientation of the vehicle. The terms "under" and "low" indicate that the term "upper" or "high" is closer to the ground along the vertical direction. The term "prior" indicates the positioning of the direction oriented in front of the vehicle in the horizontal direction, and the term "post" means positioning along the rear direction of the vehicle in the same direction. On different drawings, the same reference numerals indicate the same or similar elements.
 First, reference figure 1. The chassis 2 is part of a base for use as a chassis of a motor vehicle. This part is the most exposed to water, mud, gravel and softer. The bracket 4 of the vehicle is a support made of metal and can support the engine of the vehicle. The bracket 4 is fixed below the front of the chassis 2 by one of the ends of itself. Since the bracket 4 needs to support the relatively large weight, at least one reinforcing member 6 is present to strengthen the connection between the bracket 4 and the chassis 2. The reinforcing member may exhibit a metal tension member, such as by steel. The reinforcing member advantageously presents the form of a U-shaped profile having a bottom portion and two side wings and is configured to open toward the surface direction. Preferably, at least two reinforcing members are disposed between the bracket and the chassis. The rear end of the reinforcing member ( figure 1 It is not visible) fixed to the chassis 2, and the front end of the reinforcing member 6 is fixed to the bracket 4.
 In order to limit the risk of damage to the bottom plate under the side of the guide plate 8, the bottom plate is arranged to be as close as possible to the lower surface of the engine of the bracket 4 and the bottom frame 2 as close as possible to the front surface of the engine. The lower surface of the front portion so as to have as large ground gaps as possible, and the rear segment of the bottom plate is arranged to be spaced apart from the lower surface of the chassis. This feature of the present invention has a general profile of the bottom plate under the bottom plate.
 Therefore, according to the present invention, the front and rear segments of the bottom plate, extend along the horizontal plane of the vertical axis, such that the front section extends along the plane than the rear segment extension The plane is high. figure 1 The bottom plate under which the bottom plate is shown, and the bottom plate is fixed to the front of the bottom frame 2 and below the rear of the bracket 4.
 As can be observed, it is observed that the soil of the bottom plate has a two-stage configuration such that the bottom plate is not capable of intensifying the reinforcing member 6 between the bracket 4 and the chassis 2. Therefore, according to a preferred embodiment of the present invention, the bottom plate underflow plate 8 is only partially covered with the reinforcing member 6. The reinforcing member 6 thus passes through the wall of the bottom plate under the bottom plate from the opening extending between the front section of the conducting plate in the bottom plate.
 figure 2 The cross-sectional view can be visualized, and the rear section of the fluid plate 8 under the bottom plate is lower than the front section. The rear section is carried out along the inclined plane along the inclined plane, whereby the air is easier to flow under the vehicle. The front stage (the front stage is positioned at the bracket 4) thus has the advantage of elevated the vertical axis of the vehicle along the rear section, facilitating the flow of air under the vehicle, and decreases In particular, damage risk when driving and offering the sidewalk.
 Advantageously, in order to minimize air and water from one or more openings 10, the bottom panel includes a tab 12 that is at at least one open position of the opening 10. The tongue 12 is preferably configured to extend from the edge of the sheet to the back section of the back section of the back section of the sheet to be extended toward the bottom direction of the profile in the bottom direction of the sheet. In order to be at least partially blocked. The opening 10 is described. However, those skilled in the art can design a tongue that extends from the edge of the opening from the opening of the front stage of the bottom plate.
 According to the present invention figure 1 with figure 2 The first embodiment shown in the middle, the tab 12 has two ends, one end and the edge of the opening, and the other end is a free end. Those skilled in the art believe that, advantageously, when the reinforcing element exhibits a U-shaped profile, the at least one tongue piece 12 is configured such that the free end of the itself is placed against the reinforcing element 8 or abutting against the bottom of the reinforcing element.
 According to a second embodiment of the present invention, each of the ends of the tongue is coupled to opposite edges of the opening in order to divide the opening into two. Thereby, two side openings are defined, and the two side openings are passed through the wings of the profiles forming the reinforcing member. Preferably, the tongue comprises an aperture for receiving a fixing member, the orifice being configured to align the reinforcing member with the bracket fixed to the bracket. When the tongue is coupled to the edge of the opening by one or both ends, the tongue advantageously has a curved profile to partially dispose of a plane parallel to the plane of the bottom of the reinforcing member. The profile thus allows air to continuously flow on the bottom plate, and facilitates the aerodynamic characteristics of the vehicle.
 Ideally, at least one tongue 12 is integrally formed with the bottom plate. The bottom plate is preferably made of a plastic material (preferably thermoplastic material), the plastic material selects from the following material: acrylonitrile-butadiene-styrene copolymer (ABS), polypropylene (PP), polyexophenylene dimethylamide (PPA), polyether ether ketone (PEEK), polyphenylene sulfide (PPS), polyamide imide (PAI), polyetherimide (PEI), gather Namide (PAA) and / or polyamide (PA). Therefore, one or more tongs 12 and one or more openings 10 can be implemented during the molding operation of the bottom plate. Optionally, the plastic material used is a composite material comprising a thermoplastic substrate and a fiber reinforcing material (e.g., glass fiber).
 figure 1 with figure 2 The possibility of presence the flange 14 is shown, and the flange is at the opening 10 position and oriented into a vertical axis of the vehicle. As can be seen, the flange 14 extends from one or more of the opening 10 to the edge of the front stage position of the bottom plate under the bottom plate. The flange 14 is at least partially along the edge of the opening 10 and facilitates blocking the opening. The flange 14 extends from the bottom plate and extends up to a height position of the rear segment so that it is not in the lower side (compared to the rear segment of the bronchover plate 8 under the bottom plate). Preferably, the lower end of the flange is positioned at an intermediate plane position disposed between the rear segment of the bronze plate 8 of the bottom plate.
 According to an embodiment of the present invention, the area of the tongue sheet 12 is relying on the end of the front end of the reinforcing member 6 is equal to the area of the opening 10, and includes an aperture 16 for receiving the fixing member (see figure 2 ). When the area of the tongue 12 is equal to the entire opening, the tab 12 extends to the vertical wall 14. The aperture 16 is positioned to face the front end of the reinforcing member 6. This particular configuration can be stored between the fixing member to the bottom plate 8, the chassis 2, and the bracket 4, and absolute eliminates all vibrations caused by travel. The full blocking of the opening 10 of the bottom plate under the bottom plate can also eliminate any possibility of the external element into the operating member of the vehicle, and can maximize the air dynamics of the vehicle.
 According to a preferred embodiment of the invention, the aperture 16 is aligned with the apertures for fixing these elements (e.g., by screw), by the bracket 4 and the chassis 2. This allows the components to be quickly fixed to each other during assembly. The use of screws also allows for disassembly of structures, which is required during repair operations.
 The bottom panel 8 can protect the operating member of the vehicle (e.g., in the case of electric or mixing vehicle, the battery).