Tractor-trailer aerodynamic drag reducer

Claim 2

In combination with a tractor-trailer vehicle including a tractor roof having a leading edge and a trailing edge and a trailer body including a forward wall spaced rearwardly of the trailing edge of the tractor roof and a trailer roof having a leading edge at an elevation greater than the tractor roof, an aerodynamic drag reducer mounted on the tractor roof and comprising: a generally wedge shaped drag reducing device with side surfaces and a top surface having a leading edge and a trailing edge, the leading edge of the device being faired into the tractor roof and the top surface extending rearwardly therefrom and diverging upwardly from the tractor roof to streamline airflow around the tractor and over the trailer roof, the angle of inclination of the top surface relative the tractor roof being such that the surface thereof falls between an angle alpha which is defined by the tractor roof and a line drawn from the leading edge of the device to the leading edge of the trailer roof and an angle beta which is defined by the tractor roof and a line drawn between the leading edge of the device and the intersection of a vertical projection of the trailing edge of the device and a horizontal projection of the leading edge of the trailer roof, the leading edge of the device being of lesser width than the width of the tractor roof, the side surface extending generally vertically between the top surface of the device and the tractor roof and diverging toward the respective outboard edges of the tractor roof, the juncture of the side surface with the top surface of the tractor roof following a curvilinear path providing a concave-convex contour to the side walls to streamline airflow around the tractor and to divert air smoothly around the sides of the trailer to reduce aerodynamic drag on the tractor-trailer vehicle.

Claim 3

In a tractor-trailer vehicle including a tractor roof having a leading edge and a trailing edge and a trailer body including a forward wall spaced rearwardly of the trailing edge of the tractor roof and a roof having a leading edge at an elevation greater than the trailing edge of the tractor roof, the improvement comprising: an aerodynamic drag reducing device mounted on the tractor roof, said drag reducing device being generally wedge shaped with a top surface and side surfaces and having a leading edge and a trailing edge, the leading edge of the device being faired into the tractor roof and the top surface extending rearwardly therefrom and diverging upwardly from the tractor roof to streamline airflow around the tractor and over the trailer roof, the top surface following a curvilinear path extending rearwardly from the leading edge to a point of tangency with a line drawn between the leading edge of the device and the intersection of a vertical projection of the trailing edge of the device and a horizontal extension of the leading edge of the trailer roof, the top surface of the device continuing rearwardly beyond the point of tangency and terminating at a point intersecting a line drawn at an angle (θ) according to the formula θ = 1/2 (α + B) where (α) is the angle whose tangent is defined as (h2-h1)/(L), (B) is the angle whose tangent is defined as (h2-h1/l d ), (h1) is the height of the tractor roof above ground, (h2) is the height of the trailer roof above ground, (l d ) is the length of the drag reducing device, and (L) is the distance from the leading edge of the device to the forward wall of the trailer, the leading edge of the device being of lesser width than the width of the tractor roof, and the side surfaces extending vertically between the top surface of the device and the tractor roof and diverging toward the respective outboard edges of the tractor to streamline airflow around the tractor and the device and smoothly around the sides of the trailer.

Claim 4

In a tractor-trailer vehicle including a tractor roof having a leading edge and a trailing edge and a trailer body including a forward wall spaced rearwardly of the trailing edge of the tractor roof and a roof having a leading edge at an elevation greater than the trailing edge of the tractor roof, the improvement comprising: an aerodynamic drag reducing device mounted on the tractor roof, said drag reducing device being generally wedge shaped with a top surface and side surfaces and having a leading edge and a trailing edge, the leading edge of the device being faired into the tractor roof and the top surface extending rearwardly therefrom and diverging upwardly from the tractor roof to streamline airflow around the tractor and over the trailer roof, the top surface following a curvilinear path extending rearwardly from the leading edge to a point of tangency with a line drawn between the leading edge of the device and the intersection of a vertical projection of the trailing edge of the device and a horizontal extension of the leading edge of the trailer roof, the top surface of the device continuing rearwardly beyond the point of tangency and terminating at a point intersecting a line drawn at an angle (θ) according to the formula θ = 1/2 (α + B) where (α) is the angle whose tangent is defined as (h2-h1)/(L), (B) is the angle whose tangent is defined as (h2-h1/l d ), (h1) is the height of the tractor roof above ground, (h2) is the height of the trailer roof above ground, (l d ) is the length of the drag reducing device, and (L) is the distance from the leading edge of the device to the forward wall of the trailer, the leading edge of the device being of lesser width than the width of the tractor roof, and the side surfaces extending vertically between the top surface of the device and the tractor roof and diverging toward the respective outboard edges of the tractor to streamline airflow around the tractor and the device and smoothly around the sides of the trailer.

Claim 5

In a tractor-trailer vehicle including a tractor roof at a lower elevation than the trailer roof and spaced forwardly of the front wall of the trailer, the improvement comprising: an aerodynamic drag reducing device mounted on the tractor roof, said drag reducing device being generally wedge shaped with a top surface and side surfaces and having leading and trailing edges, the leading edge of the device being faired into the tractor roof and the top surface extending rearwardly therefrom and diverging upwardly from the tractor roof to streamline airflow around the tractor and over the trailer roof, the top surface being inclined at an angle theta according to the formula ##EQU2##where (h1) is the height of the tractor roof above ground, (h2) is the height of the trailer roof above ground, (l d ) is the length of the drag reducer and (L) is the distance from the leading edge of the device to the front wall of the trailer, the leading edge of the device being of lesser width than the width of the tractor roof, the side surface extending generally vertically between the top surface of the device and the tractor roof and diverging toward the respective outboard edges of the tractor roof, the juncture of the side surface with the top surface of the tractor roof following a curvilinear path providing a concave-convex contour to the side walls to streamline airflow around the tractor and to divert air smoothly around the sides of the trailer to reduce aerodynamic drag on the tractor-trailer vehicle.

Claim 6

In a tractor-trailer vehicle including a tractor roof at a lower elevation than the trailer roof and spaced forwardly of the front wall of the trailer, the improvement comprising: an aerodynamic drag reducing device mounted on the tractor roof, said drag reducing device being generally wedge shaped with a top surface and side surfaces and having leading and trailing edges, the leading edge of the device being faired into the tractor roof and the top surface extending rearwardly therefrom and diverging upwardly from the tractor roof to streamline airflow around the tractor and over the trailer roof, the top surface being inclined at an angle theta according to the formula ##EQU2##where (h1) is the height of the tractor roof above ground, (h2) is the height of the trailer roof above ground, (l d ) is the length of the drag reducer and (L) is the distance from the leading edge of the device to the front wall of the trailer, the leading edge of the device being of lesser width than the width of the tractor roof, the side surface extending generally vertically between the top surface of the device and the tractor roof and diverging toward the respective outboard edges of the tractor roof, the juncture of the side surface with the top surface of the tractor roof following a curvilinear path providing a concave-convex contour to the side walls to streamline airflow around the tractor and to divert air smoothly around the sides of the trailer to reduce aerodynamic drag on the tractor-trailer vehicle.

Claim 7

In a tractor-trailer vehicle including a tractor roof having a leading edge and a trailing edge and a trailer body including a forward wall spaced rearwardly of the trailing edge of the tractor roof and a roof having a leading edge at an elevation greater than the trailing edge of the tractor roof, the improvement comprising: an aerodynamic drag reducing device mounted on the tractor roof, said drag reducing device being generally wedge shaped with a top surface and side surfaces and having a leading edge and a trailing edge, the leading edge of the device being faired into the tractor roof and the top surface extending rearwardly therefrom and diverging upwardly from the tractor roof to streamline airflow around the tractor and over the trailer roof, the top surface following a curvilinear path extending rearwardly from the leading edge to a point of tangency with a line drawn between the leading edge of the device and the intersection of a vertical projection of the trailing edge of the device and a horizontal extension of the leading edge of the trailer roof, the top surface of the device continuing rearwardly beyond the point of tangency and terminating at a point intersecting a line drawn at an angle (θ) according to the formula θ = 1/2 (α + B) where (α) is the angle whose tangent is defined as (h2-h1)/(L), (B) is the angle whose tangent is defined as (h2-h1/l d ), (h1) is the height of the tractor roof above ground, (h2) is the height of the trailer roof above ground, (l d ) is the length of the drag reducing device, and (L) is the distance from the leading edge of the device to the forward wall of the trailer, the leading edge of the device being of lesser width than the width of the tractor roof, the side surface extending generally vertically between the top surface of the device and the tractor roof and diverging toward the respective outboard edges of the tractor roof, the juncture of the side surface with the top surface of the tractor roof following a curvilinear path providing a concave-convex contour to the side walls to streamline airflow around the tractor and to divert air smoothly around the sides of the trailer to reduce aerodynamic drag on the tractor-trailer vehicle.

Claim 8

In a tractor-trailer vehicle including a tractor roof having a leading edge and a trailing edge and a trailer body including a forward wall spaced rearwardly of the trailing edge of the tractor roof and a roof having a leading edge at an elevation greater than the trailing edge of the tractor roof, the improvement comprising: an aerodynamic drag reducing device mounted on the tractor roof, said drag reducing device being generally wedge shaped with a top surface and side surfaces and having a leading edge and a trailing edge, the leading edge of the device being faired into the tractor roof and the top surface extending rearwardly therefrom and diverging upwardly from the tractor roof to streamline airflow around the tractor and over the trailer roof, the top surface following a curvilinear path extending rearwardly from the leading edge to a point of tangency with a line drawn between the leading edge of the device and the intersection of a vertical projection of the trailing edge of the device and a horizontal extension of the leading edge of the trailer roof, the top surface of the device continuing rearwardly beyond the point of tangency and terminating at a point intersecting a line drawn at an angle (θ) according to the formula θ = 1/2 (α + B) where (α) is the angle whose tangent is defined as (h2-h1)/(L), (B) is the angle whose tangent is defined as (h2-h1/l d ), (h1) is the height of the tractor roof above ground, (h2) is the height of the trailer roof above ground, (l d ) is the length of the drag reducing device, and (L) is the distance from the leading edge of the device to the forward wall of the trailer, the leading edge of the device being of lesser width than the width of the tractor roof, the side surface extending generally vertically between the top surface of the device and the tractor roof and diverging toward the respective outboard edges of the tractor roof, the juncture of the side surface with the top surface of the tractor roof following a curvilinear path providing a concave-convex contour to the side walls to streamline airflow around the tractor and to divert air smoothly around the sides of the trailer to reduce aerodynamic drag on the tractor-trailer vehicle.