WO2022162571A1

WO2022162571A1 - Motorcycle with fairing having a front opening for air inflow

Info

Publication number: WO2022162571A1
Application number: PCT/IB2022/050706
Authority: WO
Inventors: Marco De Luca
Original assignee: Piaggio & C. S.P.A.
Priority date: 2021-02-01
Filing date: 2022-01-27
Publication date: 2022-08-04
Also published as: JP2024504833A; EP4284701A1; IT202100002006A1

Abstract

In a motorcycle with fairing (1), to facilitate the inflow of air from the front into the fairing (21), a front opening (23) is provided in the front portion of the fairing (21). The front opening (23) has a smaller extension in vertical direction with respect to the fairing itself, so that the upper area of the front portion of fairing is open to allow the direct inflow of an air flow (F) generated by the forward movement of the motorcycle (1). Vice versa, the lower area of the front portion of the fairing (21) is closed by a covering (31) which forms an aerodynamic profile with a front outer surface (31a) and a rear inner surface (31b), which divides a descending flow of air into an outer partial flow (FA) and an inner partial flow (FB).

Description

MOTORCYCLE WITH FAIRING HAVING A FRONT OPENING FOR AIR INFLOW

DESCRIPTION

TECHNICAL FIELD

[0001] The present invention relates to motorcycles cooled with water or with another liquid coolant and equipped with a fairing, for example, but not exclusively, racing motorcycles.

BACKGROUND ART

[0002] High performance motorcycles are typically equipped with internal combustion engines cooled with a liquid coolant, such as water or water-based blends. The radiator for cooling the liquid coolant is usually positioned between the front steered wheel and the engine. Frequently, in particular in racing motorcycles, the engine and the frame of the motorcycle are at least partially surrounded by a fairing. The fairing is open at the front to allow entry into the radiator of the air flow generated by the movement of the motorcycle.

[0003] Much effort has been made aimed at improving the air flow in the radiator, in particular for the purpose of reducing the negative effect caused by the presence of the front steered wheel with the respective suspension and steering column. In fact, these components obstruct the free entry into the radiator of the air flow generated by the forward movement of the motorcycle.

[0004] For example, W02020/115636 discloses a motorcycle, in which the front steered wheel is associated with a system for conveying the air laterally, which at least partially surrounds the front steered wheel and frontally collects an air flow generated by the forward movement of the motorcycle, to convey it toward the front surface of the radiator.

[0005] Notwithstanding these efforts for improvement, there is a continual need to improve the conditions for cooling engines, in particular for high performance motorcycles, in order to increase the efficiency and the power delivered by the engines, without increasing the weight of the motorcycle or adding to the motorcycle or around it components that can have a negative influence on the aerodynamic drag coefficient (CX coefficient).

SUMMARY OF THE INVENTION

[0006] In brief, in order to make the entry of the air flow generated by the forward movement of the engine into the fairing more efficient, for example to improve the conditions of heat removal from a radiator positioned in the volume defined by the fairing, the fairing has a front portion with a front opening that extends from a point at maximum height downward, without reaching the bottom of the fairing, but leaving a front covering defined by two diverging surfaces, which define an aerodynamic profile. More in particular, the covering is located under the front opening, between the latter and the bottom of the fairing, and between the right side portion and the left side portion of the fairing. The covering has a front outer surface, facing in the direction of movement of the vehicle, i.e., toward the front steered wheel. The covering also has a rear inner surface, facing the engine.

[0007] The rear inner surface and the front outer surface are joined to each other along a leading edge of the aerodynamic profile, the leading edge being along the edge that surrounds the front opening of the fairing, and diverge starting from the leading edge downward, i.e., toward the bottom of the fairing.

[0008] The aerodynamic profile formed by the rear inner surface and by the front outer surface divides an air flow, generated by the forward movement of the motorcycle and having a downward velocity component, into two flows that lap the aerodynamic profile along the front outer surface and along the rear inner surface. This generates particularly favorable conditions in terms of ground adhesion of the motorcycle during travel, and also facilitates and promotes the entry of air inside the fairing.

[0009] In general, this air flow entering the inner volume of the fairing has positive effects on the cooling conditions, regardless of the fact that the engine is completely or partly cooled by means of a liquid and/or through forced air convection.

[0010] In particularly advantageous embodiments, however, the motorcycle comprises at least one radiator to dissipate heat generated in the engine. The radiator can be a radiator for cooling lubricating oil, or for cooling water or another liquid coolant, such as water and antifreeze liquid or similar blends. In general terms, in the present context, reference will be made to a liquid coolant, this being meant as any fluid in liquid state that, circulating in a radiator, is capable of dissipating heat generated in the engine. Therefore, the term liquid coolant comprises, in the present context optionally also a lubricating fluid (lubricating oil).

[0011] When the motorcycle has a radiator positioned orthogonally to the direction of forward movement of the motorcycle behind the front opening of the fairing, i.e., between the front opening and the engine, the covering defines a flow channel approximately parallel to the front surface of the radiator. The aerodynamic profile, which is defined by the portion of fairing that forms the covering, intercepts the air flow that has a direction of flow sloping downward and divides it into a front partial flow, which laps the front outer surface, and into a rear partial flow, which enters the fairing and is conveyed toward inner heat dissipation surfaces. When at least one radiator is provided, this rear partial flow is conveyed toward the radiator.

[0012] If a radiator is present behind the covering, the rear partial flow generated by the aerodynamic profile of the covering and coming from the front area around the front steered wheel, is conveyed toward the flow channel formed in front of the front surface of the radiator, between this latter and the rear inner surface of the aerodynamic profile.

[0013] Besides promoting and improving the entry of air for the purpose of cooling the inside of the fairing, the covering can have further advantages. In particular, if at least one radiator is positioned behind the front opening of the fairing, at least partially covered by the covering, this achieves an effect of mechanically protecting the radiator from accidental impacts caused by stones or other detritus thrown backward by the front steered wheel.

[0014] Moreover, the front steered wheel has an effect of pumping hot air from the ground toward the front portion of the fairing. This hot air flow can reduce the heat exchange efficiency, in particular when a radiator positioned immediately inside the front opening is provided. The covering reduces this negative thermal effect.

[0015] Further advantageous features and embodiments of the motorcycle are defined in the appended claims, which form an integral part of the present description.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The invention will be better understood by following the description and the accompanying drawings, which illustrate a non-limiting example of embodiment of the invention. More in particular, in the drawing:

Fig.l shows a side view of a motorcycle in an embodiment;

Fig.2 shows a front view of the motorcycle of Fig.l;

Fig.3 shows an axonometric view of the motorcycle;

Fig.4 shows a detail of the front part of the motorcycle in a side view and partial section on a median plane;

Fig.5 shows a detail of the front part of the motorcycle in an axonometric view;

Fig. 6 shows a detail of the lower rear part of the motorcycle in an axonometric bottom view;

Fig.7 shows a detail of the rear part of the motorcycle in a side view;

Fig.8 shows a schematic section along a horizontal plane of the rear fork and of part of the rear driving wheel;

Fig.9 shows a schematic side view of the motorcycle with indication of the adhesion forces generated by the air flow in the lower part of the fairing; and

Fig.10 shows a side view analogous to the view of Fig.7 in a further embodiment.

DETAILED DESCRIPTION

[0017] In the context of the present description, unless otherwise specified, the terms above, below, top, bottom, right, left, upper, lower, front, rear, in front, behind, and analogous terms defining spatial positions of elements or components of the motorcycle or air flows around it, refer to a condition with the motorcycle in normal ride attitude. The term “vertical” indicates a direction parallel to the direction of the force of gravity and the term “horizontal” indicates a direction orthogonal to the vertical direction. In Fig. 2 the arrows L and R indicate the left and right direction and the arrows U and D indicate the vertical upward and downward direction.

[0018] In general terms, and as will be described in greater detail hereunder with reference to a non-limiting exemplary embodiment, a motorcycle comprising a fairing with a front portion facing a front steered wheel is provided. The front portion comprises: a front opening extending for an upper part of the vertical extension of the front portion of the fairing; and a covering for a lower part of the vertical extension of the front portion of the fairing. The covering comprises a front outer surface and a rear inner surface, and divides a descending air flow, generated by the forward movement of the motorcycle, into an outer partial flow that laps the front outer surface, and an inner partial flow that laps the rear inner surface. In embodiments described herein, the front outer surface and the rear inner surface together form an aerodynamic profile with a leading edge positioned along the perimeter edge of the front opening of the fairing.

[0019] With reference to the embodiment illustrated in the accompanying drawings, a motorcycle 1 comprises a frame 3, to which a seat 5 and an engine 7 are fixed. Frontally, the motorcycle has a front steered wheel 9, connected to a handlebar 11 and associated with a suspension, which - in the example illustrated - comprises a front fork 12. The motorcycle 1 further comprises a rear driving wheel 13, connected to the engine 7 via a transmission, for example a chain, not shown. The rear driving wheel 13 is supported by a rear fork 17 pivoted to the frame 3 about a hinge axis A (Fig. 7), parallel to the rotation axis of the rear driving wheel 13.

[0020] The engine 7 is cooled by means of a liquid coolant, for example water. The heat extracted from the engine 7 must be dissipated into the environment. In the illustrated embodiment, for this purpose at least one radiator 19, typically mounted between the engine 7 and the front steered wheel 9, is provided. In the illustrated embodiment, there are two radiators 19, for example one radiator for cooling the water (or other fluid coolant) and one radiator for cooling the lubricating oil. In general terms, the motorcycle 1 can comprise a single radiator, for example for water coolant or for lubricating oil, or two radiators, one for water and one for oil, as in the schematic example represented here. In the context of the present description and of the appended claims, the term liquid coolant is also meant as lubricating oil.

[0021] Although the features of the fairing described here are particularly advantageous in motorcycles that have at least one radiator, preferably positioned with its main surface orthogonal to the direction of movement of the vehicle, some advantages can also be achieved in motorcycles with air cooling and/or with a different position of the radiator or radiators. The direction of movement is meant as the direction of movement with the steering of the motorcycle not turned, i.e. traveling in a straight line.

[0022] When at least one radiator 19 is provided, the heat is removed by an air flow, generated by the movement of the motorcycle, which encounters the radiator 19 and passes through it, lapping the ducts through which the liquid coolant (water, oil) passes. In the embodiment illustrated, there are two radiators 19.

[0023] The frame 3 and the engine 7 are at least partially protected by a front fairing 21, which comprises a front windshield 22 to protect the handlebar and the on-board instrumentation, as well as the driver, over the front steered wheel 9.

[0024] The fairing 21 also has a left side portion 21A and a right side portion 21B at least partly flanking the engine 7 and structured to deflect the air beyond the driver G of the motorcycle 1, when the motorcycle is in movement. Reference number 34 indicates a bottom or lower wall of the fairing 21, facing the ground on which the motorcycle is supported and which joins the left side portion 21 A and the right side portion 2 IB of the fairing. The bottom 34 extends under the radiator 19 and under the engine 7 of the motorcycle 1, and from a front portion of the fairing 21 toward the rear driving wheel 13.

[0025] The front portion of the fairing 21 extends from the windshield 22, behind the front steered wheel 9 and to the bottom 34, and between the left side portion 21A and the right side portion 2 IB of the fairing. The front portion has a front opening 23 surrounded by an edge 25. The front opening 23 allows the entry of the air flow generated by the forward movement of the motorcycle inside of the fairing toward the engine 7. If at least one radiator is present, the air flow strikes the radiator, which is typically positioned inside the fairing 21, behind the front opening 23, between the edge 25 of the front opening 23 and the engine 7.

[0026] The front steered wheel 9 and the front fork 12 form an obstacle that obstructs the movement of the air flow toward the inside of the fairing 21 and in particular toward the radiator 19 or the radiators 19, when present. [0027] The front opening 23, which allows the cooling air to enter the radiator 19, does not involve the whole front portion of the fairing 21, but extends from a point of maximum height, adjacent to the windshield 22, toward the bottom of the fairing 21, only for a portion of the extension in height of the front portion of the fairing, due to the presence of a front covering 31, which extends from the bottom 34 of the fairing 21 toward the windshield 22. If the motorcycle has at least one radiator 19 positioned behind the opening 23, at least one portion of the front surface of said at least one radiator is partially covered by the front covering 31 formed by the fairing 21. This covering 31 forms, in the lower area of the front portion of the fairing 21, a pocket (Fig.3), which partly covers the front surface, i.e., the surface facing the direction of movement of the motorcycle 1, of the radiator 19, in the example illustrated of the lower radiator 19, while the upper radiator 19 is completely free, i.e., its front surface is more or less completely visible through the front opening 23 observing in the direction opposite to the direction of forward movement of the motorcycle 1. The edge 25 that surrounds the front opening 23 is therefore not completely external to the useful surface of the radiator, but has a lower portion that is located at a height substantially higher than the lowest point of the radiator 19.

[0028] The portion of fairing 21 that forms the covering 31 of the radiator 19 defines an aerodynamic profile, in the present context again indicated with the reference number 31, as visible in particular in Fig.4. More in particular, the covering 31 comprises a front outer surface 31a facing forward with respect to the direction of forward movement (arrow FF) of the motorcycle 1. The covering 31 further comprises a rear inner surface 31b facing in the direction opposite the direction of forward movement of the motorcycle 1 and hence facing the radiator 19. The front outer surface 31a and the rear inner surface 31b join to form a leading edge 31c (see in particular Fig.4), which forms part of the edge 25 that surrounds the front opening 23.

[0029] With reference to Fig.4, reference number 25A indicates the highest point of the edge 25 that surrounds the front opening 23. Therefore, 25 A is the upper end of the front opening 23. Normally, this point 25 A is located on the vertical median plane of the motorcycle 1. In Fig. 4, the letter H indicates the distance of the upper end of the front opening 23 from the bottom 34 of the fairing 21. The letter h indicates the distance between the upper end 25A of the front opening 25 and the leading edge 31c of the aerodynamic profile formed by the covering 31. The distance h is preferably equal to or greater than 20% of the distance H. Preferably, the distance h is equal to or less than 80% of the distance H. For example, the distance h can be between 10% and 60%, preferably between 20% and 50% of the distance H, and more preferably between 20% and 50%, or between 20% and 40% of H.

[0030] The aerodynamic profile 31, and more precisely its front outer surface 31a, is joined at the sides to the left side portion 21A and to the right side portion 21B (Fig.2) of the fairing 21 and is joined at the bottom to the lower wall or bottom 34 of the fairing 21. Preferably, the front outer surface 31a is tangent to the side portions 21A, 21B and to the bottom 34, and defines a joining curve without corners, for aerodynamic purposes.

[0031] The rear inner surface 31b is located at a certain distance from the front surface of the radiator 19, so as to form a channel for the entry of an air flow in a direction approximately parallel to the front surface of the radiator 19, between said radiator and the rear inner surface 3 lb of the covering 31.

[0032] In a side view, the front outer surface 31b of the covering 31 can be mainly convex, but can have a portion close to the leading edge 31c, with a concave shape, as can be seen in the accompanying drawings. In practice, in some embodiments, in a sectional view of the fairing 21 according to a vertical median plane, the front outer surface 31a has, in sequence and starting from the leading edge 31c, a profile with a first concave portion and a second convex portion. The convex portion continues downward until it joins to a lower outer surface of the portion of lower fairing 34 that extends under the engine of the motorcycle.

[0033] However, the front outer surface 31a is mainly (or completely) convex, i.e., it has a convexity facing forward, while the rear inner surface 31b is mainly (or completely) concave, i.e., has a concavity facing backward. In substance, the intersection between the vertical median plane of the motorcycle 1 and the portion of fairing that forms the covering 31 defines two curves, one mainly convex facing forward and the other mainly concave, facing backward.

[0034] The two surfaces 31a and 31b can be formed by two separate metal sheets, joined to each other along the leading edge 31c. [0035] In advantageous embodiments, in a side view the part of front outer surface 31a of the covering 31 that defines the convex portion projects forward forming an ogival-shaped or bulb-shaped portion of the fairing 21, which reduces the aerodynamic drag coefficient of the motorcycle.

[0036] The front outer surface 31a joins to the lower outer surface of the bottom 34 of the fairing defining an acceleration profile of the air flow that laps the front outer surface 31a and the lower outer surface of the fairing 21, so as to generate a reduction in the air pressure, which increases the ground adhesion of the motorcycle during travel. In Fig.9 this adhesion force is indicated with Fl.

[0037] In advantageous embodiments, the rear inner surface 31b of the aerodynamic profile formed by the covering 31 extends from the leading edge 31c downward and slopes backward, toward the radiator 19. In other words, in a side view the profile defined by the rear inner surface 31b along the median plane of the motorcycle 1 has a distance from the radiator that decreases moving from the leading edge 31c toward the lower part of the covering 31, i.e., toward the bottom 34 of the fairing 21, extending under the engine 7. When the motorcycle 1 moves forward, the air flow entering the volume inside the fairing behind the surface 31b decelerates along said surface 31b, with consequent increase in pressure, which contributes to the adhesion force F 1.

[0038] The function of the covering 31 described above is illustrated in particular in Fig.4. During the forward movement of the motorcycle 1, an air flow F is generated between the front steered wheel 9 and the upper front part of the fairing 21, which can flow both over and under a front mudguard 35 and which has a component directed downward. The upper part of the fluid stream forming the air flow F directly impacts the radiator 19, with a high velocity component orthogonal to the front surface of the radiator 19, so as to pass through the radiator 19. The lower portion of the fluid stream forming the air flow F has a high vertical velocity component, directed downward. The portion of flow directed downward encounters the leading edge 31c and is divided into a front partial flow FA and into a rear partial flow FB.

[0039] In a side view, the front partial flow FA laps the front outer surface 31a of the covering 31 and is diverted (arrow FC, Fig.4) between the bottom 34 of the fairing 21 and the ground, generating a force directed downward as a result of the acceleration along the front outer surface 31a and the ogival portion defined thereby.

[0040] The rear partial flow FB laps the rear inner surface 31b of the covering 31 and penetrates the channel defined between the rear inner surface 31b and the front surface of the radiator 19, lapping the front surface of the radiator 19 as a result of the component of velocity directed downward of the flow FB. The rear partial flow FB is decelerated with consequent increase in pressure and flows gradually through the radiator 19.

[0041] The aerodynamic shaped profile of the front outer surface 31a and of the rear inner surface 31b limits the risk of separation of the fluid stream along the surfaces and thus improves the fluid-dynamic behavior.

[0042] The deceleration of the partial flow FB in the flow pocket or channel formed between the front surface of the radiator 19 and the rear inner surface 31b of the covering 31 pushes the air through the radiator 19. The partial flow FB thus contributes efficiently to the removal of heat from the radiator 19.

[0043] In this way, the air flow F generated between the front steered wheel 9 and the upper part of the fairing 21 is utilized optimally, to cool the fluid coolant of the engine 7. Moreover, the covering 31 protects the inside of the fairing 21 from the entry of detritus and sharp objects, such as stones, which could damage mechanical members, such as the radiator. The inflow of hot air, pumped from the ground by the front steered wheel 9 in the event of very high environmental temperatures, is also reduced, with consequent improvement of the cooling conditions of the engine 7.

[0044] In the embodiment illustrated in the accompanying drawings, and in particular in Figs. 1, 7, 8 and 9, the rear fork 17 comprises two support arms 51 of the rear driving wheel 13. The two arms 51 are connected to each other by a joining structure 53 which forms a block also defining the hinge connecting the rear fork 17 to the frame of the motorcycle.

[0045] The joining structure 53 comprises a rear surface 55 facing the rear driving wheel 13. As can be seen in particular in Figs.7 and 9, in a side view, or more precisely in a sectional view along a vertical median plane of the motorcycle 1, the rear surface 55 has a lower portion that is joined to a rear portion 59 of the fairing 21. The rear portion 59 of the fairing extends from the bottom 34 of the fairing 21 upward and faces the ground and the rear driving wheel 13.

[0046] In practical embodiments, the rear surface 55 can have, in aside view, or more precisely in a sectional view along a vertical median plane of the motorcycle 1, a portion approximately parallel to the perimeter surface of the rear driving wheel 13. In some embodiments, the profile of the rear surface 55 along a vertical median plane of the motorcycle, as shown in Fig.7, can be such as to define, together with the profile of the rear driving wheel 13, a channel converging slightly in the direction of the air flow that is generated between the rear driving wheel 13 and the rear surface 55.

[0047] In practical embodiments, in a vertical median plane of the motorcycle 1 the rear surface 55 of the joining structure 53 defines a profile or curve (shown in Figs. 7 and 9), which is substantially tangent to the rear portion 59 of the fairing 21, so as to form, together with the perimeter surface of the rear driving wheel 13, an air diffusion channel.

[0048] In practice, on the vertical median plane of the motorcycle 1 the rear portion 59 of the fairing 21 and the rear surface 55 of the joining structure 53 form a curve whose first derivative is continuous in the area of transition from the rear surface 55 and the rear portion 59.

[0049] In this way, the rear portion 59 of the fairing 21 and the rear surface 55 of the joining structure 53 define a guide profile of the air flow around the rear driving wheel 13.

[0050] In some embodiments, the joining structure 53 and the rear portion 59 of the fairing 21 can be configured so as to maintain a continuity of the surface defining the diffusion channel of the air flow around the rear driving wheel 13 regardless of the pivoting movement of the rear fork 17 around the axis A, for example as a result of the load represented by the driver G, or as a result of movements caused by roughness of the ground and/or by dynamic effects. For example, for this purpose the two mutually tangent surfaces of the rear portion 59 of the fairing 21 and of the joining structure 53 can have areas slidably coupled to each other.

[0051] In the illustrated embodiment, the rear portion 59 of the fairing 21 has an upper end edge 61 (Fig.6) facing the fork 17, which is spaced from said fork. Moreover, the upper end edge 61 is provided with a notch 63 facing the rear fork 17. A deflector 65, of a shape complementary to the notch 63, is integral with the rear fork 17. In an angular position of the rear fork 17 the deflector 65 is approximately flush with the inside of the notch 63 to form a substantially continuous surface. When the rear fork 17 rotates upward around the axis A with respect to the aforesaid position, the deflector 65 moves away from the rear portion 59 of the fairing 21 causing a gap 70 to open in the rear portion 59 of the fairing, in front of which gap the deflector 65 is positioned. This forms a guide profile for the air flow exiting from the inside of the fairing 21 through the gap defined by the notch 63, forcing this flow through the channel defined between the perimeter surface of the rear driving wheel 13 and the rear surface 55 of the joining structure 53.

[0052] In this way a guide for the air flow is obtained around the rear portion of the fairing 21 and between the rear surface 55 of the joining structure 53 of the fork 17 and the rear driving wheel 13, improving the flow conditions, reducing phenomena of vorticity that cause an increase in the rolling resistance of the motorcycle and also optimizing cooling conditions of the rear driving wheel 13 as a result of the air flow guided in the flow channel.

[0053] Acceleration of the air flow around the rear portion 59 of the fairing 21 toward the rear surface 55 of the joining structure 53 also causes an aerodynamic effect with a force directed downward, which increases the ground adhesion of the motorcycle 1 (arrow F2 in Fig.9).

[0054] This adhesion can be further increased using an upside down airfoil 67 integral with the rear fork 17 and positioned under the plane on which the rotation axis of the rear driving wheel 13 and the hinge axis A of the rear fork 17 lie. The airfoil 67 is upside down, in the sense that the high pressure surface, along which the air flow decelerates, is facing upward and the low pressure surface, along which the air flow accelerates, is facing downward. The leading edge of the airfoil 67 is facing forward and the trailing edge is facing toward the rear driving wheel 13 and is located in front of the rear driving wheel 13 with respect to the direction of forward movement (arrow FF) of the motorcycle 1.

[0055] In particularly advantageous embodiments, a rear mudguard 69 with a rear surface 71 facing the rear driving wheel 13 can be fixed to the rear fork 17. In a side view, and in particular in a sectional view along a vertical median plane of the motorcycle 1, the rear surface 71 of the rear mudguard 69 can be substantially tangent to the rear surface 55 of the joining structure 53, as can be seen in particular in Fig.7. In substance, the rear surface 71 of the rear mudguard 69 intersects the vertical median plane of the motorcycle 1 along a profile that forms the extension of the profile defined by the intersection of the rear surface 55 and of the rear portion 59 of the fairing 21 with the vertical median plane.

[0056] This defines a flow channel extending around the rear driving wheel 13 for a portion of the extension of this later that can reach as far as the upper area of the rear driving wheel 1, under the seat of the motorcycle 1 along which the air flow FE is guided. This flow channel provides an efficient guide for the air flow FE generated by the forward movement of the motorcycle 1, a reduction in aerodynamic drag and an effective cooling on the rear tire.

[0057] Fig. 10 shows a view similar to the view of Fig.7, of an improved embodiment. In particular, this embodiment provides solutions aimed at optimizing the effect of the flow generated by the structure of the rear fork 17, and in particular of its rear surface 55, in combination with the rear portion 59 of the fairing 21.

[0058] As can be seen in Fig. 10, a shield 100, which extends around the perimeter surface of the tire of the rear driving wheel 13, is arranged between the two arms 51 of the fork 17. As can be understood by looking at Fig.10, the shield 100 can be in the form of a wall with a three-dimensional curvature, substantially corresponding to the curvature of the tire of the rear driving wheel 14, positioned at a certain distance from the tread of said tire. In practice, the surface of the shield 100 facing the rear driving wheel 13 can form an envelope of the rear driving wheel 13, at a preferably constant distance therefrom.

[0059] The shield 100 has an upper portion 100a and a lower portion 100b. In the illustrated embodiment, the portion 100a has an angular extension equal to an angle a and the portion 100b has an angular extension equal to an angle p. In some embodiments, the angular extension of the two portions 100a, 100b, and hence the total angular extension of the shield 100, can be fixed. A set of shields with different angular extensions can be provided to adapt the motorcycle 1 to different riding conditions, for the purposes clarified below. In other embodiments, the two portions 100a, 100b can be movable one with respect to the other, so as to overlap to a larger or smaller extent and consequently vary the total angular extension thereof. This variation can be controlled manually, for example by making the two portions 100a and 100b in two parts fixable one with respect to the other in variable angular positions. In other, more sophisticated, embodiments, the angular extension of the shield 100 can be modified with a servo-assisted system, optionally by means of a control accessible to the driver G during riding. For this purpose, an electric, pneumatic or hydraulic actuator can be provided. It would also be possible to control lengthening and shortening of the shield 100 by means of a mechanical control with an operating member positioned on the handlebar or otherwise accessible to the driver during riding.

[0060] The function of the shield 100 is to shield the tire of the rear driving wheel 13to a greater or lesser extent, as a function of its angular extension (a+P). In this way, by shielding the tire of the rear driving wheel 13 to a greater or lesser extent, the temperature of the tire can be adjusted, i.e., a greater or lesser cooling effect of the tire can be imparted as a result of the air flow conveyed in the channel formed by the rear portion 59 of the fairing 21 and by the rear surface 55 of the rear fork 17.

[0061] The angular extension (a+P) of the shield 100 can be modified (manually or in a servo-assisted manner) as a function of the riding conditions, of the type of tire mounted, of the ambient temperature, of the type of road surface, etc. It would also be possible, in the case of servo-assisted operation, to automate the control of the angular extension of the shield 100 based on a temperature signal generated by a temperature sensor that detects the surface temperature of the rear tire.

[0062] Moreover, in the event of rain, the shield 100 prevents the flow of rainwater channeled between the rear surface 59 of the fork and the rear driving wheel 13 from flooding the rear driving wheel 13 during travel. This maximizes the grip in adverse weather conditions.

Claims

1. A motorcycle (1) comprising: a frame (3); an internal combustion engine (7) mounted on the frame; at least one front steered wheel (9); a rear driving wheel (13); a front fairing (21) at least partially surrounding the frame (3) and comprising:

- a windshield (22) over the front steered wheel (9);

- a right side portion (21A) and a left side portion (21B) at least partly flanking the engine (7) and structured to deflect the air beyond the driver of the motorcycle (1) when the motorcycle is moving;

- a bottom (34) that faces the ground, which joins the left side portion (21A) and the right side portion (21B) of the fairing (21) to each other and which extends under the engine (7);

- a front portion descending downward from the windshield (22) and joined at the sides to the left side portion (21 A) and to the right side portion (21B) and at the bottom to the bottom (34) of the fairing (21); wherein: the front portion comprises a front opening (23) adapted to allow the entry of air inside the fairing (21) when the motorcycle (1) is moving, the front opening being surrounded by an edge (25); the front portion comprises a covering (31) extending from the edge (25) surrounding the front opening (23) toward the bottom (34) of the fairing (21), the covering (31) comprising a front outer surface (31a) oriented toward the front steered wheel (9) and a rear inner surface (3 lb) oriented toward the engine (7); and the front outer surface (31a) and the rear inner surface (31b) diverge with respect to each other from the edge (25) of the opening (23) toward the bottom (34) of the fairing (21), so as to form an aerodynamic profile having a leading edge (31c) along the edge (25) surrounding the front opening (23).

2. The motorcycle (1) of claim 1, wherein the covering (31) is joined at the sides to the right side portion (21B) and to the left side portion (21A) of the fairing (21) and at the bottom to the bottom (34) of the fairing (21).

3. The motorcycle (1) of claim 1 or 2, wherein the front opening (23) extends downward from an upper end (25 A) of the front opening to the leading edge (31c) of the aerodynamic profile; the leading edge (31c) of the aerodynamic profile being positioned at a distance (h) from the upper end (25A) of the front opening (23) equal to or greater than 20% of the distance (H) between the upper end (25 A) of the front opening (23) and the bottom (34) of the fairing (21).

4. The motorcycle (1) of claim 3, wherein the leading edge (31c) of the aerodynamic profile is at a distance from the upper end of the front opening equal to or less than 90%, preferably equal to or less than 80%, of the distance between the upper end of the front opening (23) and the bottom (34) of the fairing (21).

5. The motorcycle (1) of one or more of the preceding claims, wherein the front opening (23) is arranged in the top part of the front portion so as to be closer to the windshield (22) than to the bottom (34) of the fairing (21).

6. The motorcycle (1) of one or more of the preceding claims, comprising at least one radiator (19) for cooling at least one liquid coolant of the engine (7); wherein said at least one radiator (19) has a front surface facing forward in the direction of forward movement of the motorcycle (1); and wherein said at least one radiator (19) is arranged behind the front opening (23) so as to receive an air flow (F) that passes through the front opening (23) when the motorcycle (1) is moving.

7. The motorcycle (1) of claim 6, wherein said at least one radiator (19) is positioned at least partly behind the covering (31) with respect to the direction of forward movement of the motorcycle (1).

8. The motorcycle (1) of claim 6 or 7, wherein the rear inner surface (31b) of the covering (31) is joined to said at least one radiator (19) according to a direction substantially orthogonal to the front surface of said at least one radiator (19).

9. The motorcycle (1) of one or more of the preceding claims, wherein the front outer surface (31a) of the covering (31) is at least partially convex and extends forward with respect to the leading edge (31c) of the aerodynamic profile.

10. The motorcycle (1) of one or more of the preceding claims, where- in the rear inner surface (31b) of the covering (31) is at least partially concave and slopes backward with respect to the leading edge (31c) of the aerodynamic profile toward the engine (7).

11. The motorcycle (1) of one or more of the preceding claims, wherein the front outer surface (31a) and the rear inner surface (31b) of the covering (31) are configured to divide an air flow (F), generated by the forward movement of the motorcycle (1) and which flows around and over the front steered wheel (9), into a rear partial flow (FB), conveyed along the rear inner surface (31b) of the covering (31), and a front partial flow (FA), conveyed along the front outer surface (31a) of the covering (31).

12. The motorcycle (1) of claim 11, wherein the front outer surface (31a) of the covering (31) tangentially joins to the bottom (34) of the fairing (21) and is configured so that during the forward movement of the motorcycle (1) the front partial flow (FA) accelerates along the front outer surface (31a) creating a reduction in pressure that increases the ground adhesion of the motorcycle (1).

13. The motorcycle (1) of claim 11 or 12, when dependent on at least claim 7, wherein a pocket is formed between the rear inner surface (31b) of the covering (31) and said at least one radiator (19), said pocket being configured to collect and slow down the rear partial flow (FB) generated during the forward movement of the motorcycle (1), generating an increase in pressure that increases the ground adhesion of the motorcycle (1).

14. The motorcycle of one or more of the preceding claims, wherein the front outer surface (31a) of the covering (31) has an ogival shape with a convexity oriented toward the front in the direction of travel of the motorcycle (1).

15. A motorcycle comprising a fairing (21) with a front portion facing a front steered wheel (9); wherein the front portion comprises: a front opening (23) extending for an upper part of the vertical extension of the front portion of the fairing, and a covering for a lower part of the vertical extension of the front portion of the fairing; and wherein the covering (31) forms an aerodynamic profile with a front outer surface (31a), oriented toward the front steered wheel (9), and a rear inner surface (31b), oriented toward the engine (7); wherein the front outer surface and the

17 rear inner surface diverge with respect to each other; wherein the aerodynamic profile divides a descending air flow, generated by the forward movement of the motorcycle, into an outer partial flow (FA) and an inner partial flow (FB).

16. A motorcycle as claimed in claim 15, comprising one or more of the features of claims 2 to 14.

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