Patent Description:
The cost of fuel is typically the largest cost associated with operating a tractor trailer. A tractor trailer in regular full-time operation may use <NUM>,<NUM> liters (<NUM>,<NUM> gallons) or more of diesel fuel per year. Fuel costs are similarly high for bus vehicles. Even small improvements in fuel efficiency can have a significant impact on aggregate fuel costs for operators of truck, tractor, or bus vehicles. Decreases in fuel consumption would also lead to concomitant reductions in emissions such as NOx, SOx, particulates, and unburned hydrocarbons.

Increasing combustion pressure in engines and development of exhaust treatment systems often require increased cooling capacity; however, aerodynamic efficiency is typically promoted by reducing the size of airflow openings at the front of a tractor trailer.

<FIG> is a front elevational view of a front exterior of a tractor <NUM> of a tractor trailer, showing left and right fenders 12A, 12B that are laterally arranged relative to a hood <NUM> that serves as a cover for an engine of the tractor. The hood <NUM> and fenders 12A, 12B may be part of a unitary fairing configured to tilt forward to permit access to the tractor engine for servicing. As shown, the left and right fenders 12A, 12B increase in width, and a remainder of the hood <NUM> decreases in width, with increasing proximity to a front end <NUM> of the tractor <NUM>. A primary front opening <NUM> is arranged below a forward end of the hood <NUM> and between the fenders 12A, 12B, and permits ingress of air into an engine compartment for thermal interaction with one or more heat exchangers such as a front radiator. As shown, a conventional front closing cross-member <NUM> is arranged within the primary front opening <NUM>. The front closing cross-member <NUM> has a ladder-like shape, with a generally rectangular perimeter and several apertures <NUM> defined therein to permit the passage of air. <FIG> is a front elevational view of a portion of <FIG>, showing an exposed portion of the front closing cross-member <NUM> (including apertures <NUM> defined therein) within the primary front opening <NUM>.

A front closing cross-member is an integral part of a chassis frame (also referred to as a chassis frame ladder) of the truck portion of a tractor trailer. A front closing cross-member sets the front width of the chassis frame ladder, provides structural rigidity at the front end of the tractor, and is critical in promoting proper chassis and hood alignment.

<FIG> is a rear perspective view of the front closing cross-member <NUM> of <FIG> attached to left and right multi-function brackets (MFBs) 24A, 24B that embody forward portions of a tractor frame. As used herein, the terms "left," "right," "forward," and so on, are used in a manner relative to the perception of a person present in the driver's seat of a truck, such that "left" corresponds to the driver's side, "right" corresponds to the passenger's side, etc. The MFBs 24A, 24B are used to support a hood opening mechanism, to support tow hooks, to support engine cooling components, and to provide corner interfaces between longitudinal rails (not shown) and the front closing cross-member <NUM> as portions of a tractor frame. <FIG> is a front perspective view of the front closing cross-member <NUM> and MFBs 24A, 24B of <FIG>, with left and right longitudinal rails 26A, 26B fastened to the left and right MFBs 24A, 24B, respectively. As shown, the front closing cross-member <NUM> is secured to the MFBs 24A, 24B with left and right groups of longitudinal bolts 28A, 28B, and the left and right longitudinal rails 26A, 26B are secured to the MFBs 24A, 24B with left and right groups of transverse bolts 29A, 29B, respectively.

<FIG> is a side cross-sectional schematic view of an engine compartment <NUM> of a tractor (i.e., of a tractor-trailer) incorporating the front closing cross-member <NUM> of <FIG> B and 2A-2B positioned in a primary front opening <NUM> of the tractor. The primary front opening <NUM> is defined between bounding members <NUM>, <NUM>' (optionally part of a front fairing). As shown, the front closing cross-member <NUM> is positioned forward of a front radiator <NUM>, which is arranged forward of an engine <NUM> within the engine compartment <NUM>. Horizontal arrows show the direction of airflow through the primary front opening <NUM>, as well as past the front closing cross-member <NUM> and through apertures <NUM> defined therein, to impinge on the front radiator <NUM>. Unfortunately, the shape of the conventional front closing cross-member <NUM> provides significant aerodynamic drag and causes a turbulent airflow wake downstream of the front closing cross-member <NUM> when the tractor is traveling at highway speeds. <FIG> is a side cross-sectional view of a portion of the front closing cross-member <NUM> of <FIG> (with an aperture <NUM> defined therein), with superimposed streamlines showing a turbulent airflow wake <NUM> downstream of the front closing cross-member <NUM>. This turbulent airflow wake <NUM> results in localized low pressure regions along a face of the front radiator (element <NUM> shown in <FIG>), which detrimentally limits transfer of heat between the air and the front radiator <NUM>.

A need therefore exists in the art for improved front closing cross-members and road vehicles incorporating the same, to address limitations associated with conventional front closing cross-members.

Aspects of the disclosure relate to a front closing cross-member including a medial portion having an airfoil-like shape arranged between left and right end portions of greater height than the medial portion. The medial portion includes a trailing edge having a height less than a height of a leading edge thereof. The left and right end portions are configured to be mounted to at least a portion of a structural frame of the road vehicle (e.g., by using fasteners extending through multiple apertures defined in the end portions). The novel front closing cross-member may exhibit the same or greater stiffness and torsional rigidity as a conventional front closing cross-member, while exhibiting reduced drag and facilitating formation of a laminar airflow wake to permit improved cooling of a front radiator positioned downstream of the front closing cross-member.

One aspect of the present disclosure provides a front closing cross-member for a road vehicle. The front closing cross-member comprises left and right portions, and a medial portion having a leading edge, a trailing edge, and an airfoil-like cross-sectional shape. The trailing edge has a height less than a height of the leading edge, and the medial portion is arranged between the left and right end portions. Each of the left and right end portions has a height greater than a maximum height of the medial portion, and each of the left and right end portions is configured to be mounted to at least a portion of a structural frame of the road vehicle.

In certain embodiments, the front closing cross-member comprises a left transition portion arranged between the left end portion and the medial portion, and a right transition portion is arranged between the right end portion and the medial portion. The left transition portion comprises a height that increases from a medial end thereof (i.e., proximate to the medial portion) to a lateral end thereof (proximate to the left end portion) to provide a height transition between the medial portion and the left end portion. The right transition portion comprises a height that increases from a medial end thereof (i.e., proximate to the medial portion) to a lateral end thereof (proximate to the right end portion) to provide a height transition between the medial portion and the right end portion.

In certain embodiments, a left opening is defined between a portion of the left transition portion and the left end portion, and a right opening is defined between a portion of the right transition portion and the right end portion.

In certain embodiments, the medial portion, the left and right end portions, and the left and right transition portions comprise a single unitary element. In certain embodiments, the medial portion, the left and right end portions, and the left and right transition portions comprise a single casting of metal or metal alloy.

In certain embodiments, the medial portion comprises a first average thickness extending in a front-to-rear direction; each of the left end portion and the right end portion comprises a second average thickness extending in the front-to-rear direction; and the first average thickness is greater than the second average thickness.

In certain embodiments, the medial portion comprises a first average thickness extending in a front-to-rear direction; each of the left end portion and the right end portion comprises a second average thickness extending in the front-to-rear direction; each of the left transition portion and the right transition portion comprises a third average thickness extending in the front-to-rear direction; the first average thickness is greater than the second average thickness; and the third average thickness is between the first average thickness and the second average thickness.

In certain embodiments, the medial portion comprises an arcuate shape when viewed from above, with a front surface at a center of the medial portion arranged forward of the front surface at ends of the medial portion.

In certain embodiments, each end portion of the left and right end portions defines a plurality of apertures, and each aperture of the plurality of apertures is configured to receive a fastener arranged to couple the end portion to the at least a portion of the structural frame of the road vehicle.

In certain embodiments, for each end portion of the left and right end portions, the plurality of apertures defines at least three (or at least four) apertures that are vertically aligned, with central axes of the apertures being parallel to one another.

In certain embodiments, a plurality of wiring harness mounting regions arranged along or proximate to the trailing edge of the medial portion.

In certain embodiments, the leading edge comprises a first curved surface, the trailing edge comprises a second curved surface, the medial portion comprises a generally symmetric airfoil shape that provides a zero degree angle of attack relative to a horizontal plane when the front closing cross-member is mounted to a truck frame and exposed to an oncoming airflow in a horizontal direction.

In another aspect, the disclosure relates to a front closing cross-member for a road vehicle, the front closing cross-member comprising left and right end portions, left and right transition portions, and a medial portion having a leading edge, a trailing edge, and an airfoil-like cross sectional shape with the trailing edge having a height less than a height of the leading edge. The left and right end portions are configured to be mounted to at least a portion of a structural frame of the road vehicle. The left transition portion is arranged between the left end portion and the medial portion, and the right transition portion is arranged between the right end portion and the medial portion. The left and right end portions each have a height greater than a maximum height of the medial portion. The left transition portion provides a height transition between the medial portion and the left end portion, and the right transition portion provides a height transition between the medial portion and the right end portion. The medial portion comprises a first average thickness extending in a front-to-rear direction, and the left and right end portions each comprise a second average thickness extending in the front-to-rear direction; with the first average thickness being greater than the second average thickness.

In certain embodiments, a left opening is defined between a portion of the left transition portion and the left end portion, a right opening is defined between a portion of the right transition portion and the right end portion. Additionally, each end portion of the left and right end portions defines a plurality of apertures, each aperture of the plurality of apertures is configured to receive a fastener arranged to couple the end portion to the at least a portion of the structural frame of the road vehicle, and for each end portion of the left and right end portions, the plurality of apertures defines at least three apertures (or at least four apertures) that are vertically aligned, with central axes of the apertures being parallel to one another.

In certain embodiments, a road vehicle frame comprises a front closing cross-member as disclosed herein attached to first and second multi-function brackets of the road vehicle. Such brackets multi-function brackets may be further attached to left and right longitudinal rails of a frame of the road vehicle.

In certain embodiments, a road vehicle comprises an engine, a radiator, and a front closing cross-member as disclosed herein, wherein the radiator is positioned forward of the engine, and the front closing cross-member is positioned forward of the radiator.

In another aspect, any one or more aspects or features described herein may be combined with any one or more other aspects or features for additional advantage.

Other aspects and embodiments will be apparent from the detailed description and accompanying drawings.

The present disclosure relate to a front closing cross-member including a medial portion having an airfoil-like shape arranged between left and right end portions of greater height than the medial portion. The medial portion includes a trailing edge having a height less than a height of a leading edge thereof. The left and right end portions of increased height relative to the medial portion are configured to be mounted to at least a portion of a structural frame of the road vehicle. The front closing cross-member may exhibit the same or greater stiffness and torsional rigidity as a conventional front closing cross-member, while exhibiting reduced drag and facilitating formation of a laminar airflow wake. Such an airflow wake may avoid formation of low pressure regions inherent to turbulent airflow wakes, and permit improved cooling of a front radiator positioned downstream of the novel front closing cross-member, relative to use of a conventional front closing cross-member as described in the background portion of the present disclosure.

Details of illustrative embodiments are described hereinafter. As noted previously, the terms "left," "right," "forward," and so on, are used herein in a manner relative to the perception of a person present in the driver's seat of a truck, such that "left" corresponds to the driver's side, "right" corresponds to the passenger's side, etc..

<FIG> is a front elevational view of a front closing cross-member <NUM> according to one embodiment of the present disclosure. Additional views (i.e., a front perspective view, a magnified portion of the front perspective view, and a cross-sectional view) of the front closing cross-member <NUM> are provided in <FIG>. Referring to <FIG>, the front closing cross-member <NUM> includes a medial portion <NUM> arranged between left and right end portions 46A, 46B, with left and right transition portions 44A, 44B being provided between the medial portion <NUM> and the left and right end portions 46A, 46B, respectively. The left and right transition portions 44A, 44B each have a generally triangular shape. The front closing cross-member <NUM> further includes left and right ends 50A, 50B. As shown, each of the left and right end portions 46A, 46B has a height that is substantially greater (e.g., at least about three times, about four times, or about five times greater in certain embodiments) than a height of the medial portion <NUM>. The left transition portion 44A has a height that increases from a medial end 43A to a lateral end 45A of the left transition portion 44A to provide a height transition between the medial portion <NUM> and the left end portion 46A. Similarly, the right transition portion 44B has a height that increases from a medial end 43B to a lateral end 45B of the right transition portion 44B to provide a height transition between the medial portion <NUM> and the right end portion 46B. A left opening 48A is defined between a portion of the left transition portion 44A and the left end portion 46A, and a right opening 48B is defined between a portion of the right transition portion 44B and the right end portion 46B, wherein the left and right openings 48A, 48B are provided to reduce aerodynamic drag and weight of the front closing cross-member <NUM>. The left and right end portions 46A, 46B each have a rounded, generally rectangular shape and each defines four vertically aligned apertures 52A, 52B that are configured to permit insertion of fasteners (e.g., bolts, not shown) in a longitudinal direction for attachment of the end portions 46A, 46B of the front closing cross-member <NUM> to at least one portion of a vehicular frame (such as left and right multi-function brackets (MFBs) thereof, as shown hereinafter in connection with <FIG>). With each group of vertically aligned apertures 52A, 52B, the respective apertures have central axes that are parallel to one another.

<FIG> is a front perspective view of the front closing cross-member <NUM>, and <FIG> is a magnified front perspective view of part of the front closing cross-member <NUM>, including a cross-sectional view of the medial portion <NUM>. As shown in <FIG> and <FIG>, each transition portion 44A, 44B has a thickness in a front-to-rear direction that is reduced with proximity to the end portions 46A, 46B. Additionally, the medial portion <NUM> has an average thickness in a front-to-rear direction that is greater than an average thickness of the transition portions 44A, 44B, and an average thickness of the transition portions 44A, 44B is greater than an average thickness of the end portions 46A, 46B. As further shown in <FIG> and <FIG>, the medial portion <NUM> includes a curved leading edge <NUM> and a curved trailing edge <NUM>, with a downwardly sloping upper surface <NUM> and an upwardly sloping lower surface <NUM> extending therebetween. The end portions 46A, 46B each define four vertically aligned apertures 52A, 52B, which are substantially equally spaced and extend through the respective end portions 46A, 46B in a longitudinal direction.

<FIG> is a cross-sectional view of the medial portion <NUM> of the front closing cross-member <NUM> of <FIG>. As noted previously, the medial portion <NUM> includes a curved leading edge <NUM> and a curved trailing edge <NUM>, with a downwardly sloping upper surface <NUM> and an upwardly sloping lower surface <NUM> extending therebetween. The curved leading edge <NUM> has a height HL that is greater (e.g., at least <NUM>% greater, <NUM>% greater, <NUM>% greater, <NUM>% greater, or <NUM>% greater in certain embodiments) than a height of the curved trailing edge HT. In certain embodiments, the medial portion <NUM> is generally symmetric relative to a horizontal plane (not shown).

In certain embodiments, a front closing cross-member as disclosed herein (i.e., including a medial portion, transition portions, and end portions thereof according to the front closing cross-member <NUM> of <FIG>) may embody a unitary single member. Various fabrication techniques that may be used including one or more of casting, machining, forging, welding, additive material deposition, and/or subtractive material removal. In certain embodiments, a front closing cross-member may be fabricated of a metal or metal alloy (including but not limited to spheroidal graphite cast iron (also known as ductile iron), aluminum, steel, alloy steel, or the like). Ductile iron is a type of cast iron known for its impact and fatigue resistance, elongation, and wear resistance due to the spherical (round) graphite structures in the metal.

In certain embodiments, a front closing cross-member as disclosed herein may be produced by lost foam casting. A lost foam casting is created by a type of evaporative-pattern casting process where a polystyrene foam pattern is used to form a mold. The foam pattern is coated and embedded with a ceramic bead medium compacted around it to support the external form of the foam. Other casting techniques (e.g., green sand casting) may be used in certain embodiments, but lost foam casting is preferable to provide higher resolution features, tighter dimensional tolerances, and smoother surface finishes that may reduce or eliminate the need for post-casting finishing steps (e.g., machining). In certain embodiments, various portions of a front closing cross-member may be separately produced (e.g., cast) and joined together by welding or other means to form a final product.

<FIG> is a front elevational view of a portion of a first road vehicle frame 66A including the front closing cross-member <NUM> of <FIG> and a lower cross-member <NUM> both spanning between left and right multi-function brackets 24A, 24B. Unlike the front closing cross-member <NUM>, the lower cross-member <NUM> is generally rectangular in shape without exhibiting an aerodynamic profile, but little utility would be gained by reshaping the lower cross-member <NUM> since it is arranged behind a front bumper or fairing of the tractor without being directly exposed to a flow of incoming air when the tractor is traveling in a forward direction. The front closing cross-member <NUM> is secured to the MFBs 24A, 24B with left and right groups of longitudinal bolts 62A, 62B that extend through end portions 46A, 46B of the front closing cross-member <NUM>. Left and right groups of transverse bolts 64A, 64B may also be provided.

<FIG> is a front perspective view of the road vehicle frame portion 66B of <FIG> with the addition of left and right longitudinal rail members 26A, 26B affixed to the left and right MFBs 24A, 24B thereof. As shown, the front closing cross-member <NUM> is secured to the MFBs 24A, 24B with left and right groups of longitudinal bolts 62A, 62B that extend through end portions 46A, 46B of the front closing cross-member <NUM>. Additionally, the left and right groups of transverse bolts 64A, 64B may be used to join the MFBs 24A, 24B to the longitudinal rail members 26A, 26B.

<FIG> provide front and rear elevational views, respectively, of a portion of a second road vehicle frame 66C including the front closing cross-member <NUM> of <FIG> and a lower cross-member <NUM> both spanning between left and right MFBs 24A, 24B, with each MFB 24A, 24B including a tow hook 25A, 25B. The front closing cross-member <NUM> is secured to the MFBs 24A, 24B with left and right groups of longitudinal bolts 62A, 62B that extend through end portions 46A, 46B of the front closing cross-member <NUM>. <FIG> show that the medial portion <NUM> of the front closing cross-member <NUM> may have an arcuate shape when viewed from above, with a front surface at a center of the medial portion <NUM> arranged forward of the end portions 46A, 46B, and arranged forward of front surfaces at distal ends of the medial portion <NUM>. As shown in <FIG>, a plurality of wiring harness mounting regions <NUM> (e.g., holes, optionally being threaded) may be arranged along or proximate to a trailing edge of the medial portion <NUM>, to receive fasteners for permitting wires (e.g., for sensors or other components) to be mounted along a rear of the medial portion <NUM>.

<FIG> is a side cross-sectional schematic view of an engine compartment <NUM> of a tractor (i.e., of a tractor-trailer) incorporating the front closing cross-member <NUM> of <FIG> positioned in a primary front opening <NUM> of the tractor. The primary front opening <NUM> is defined between bounding members <NUM>, <NUM>' (optionally part of a front fairing). As shown, the front closing cross-member <NUM> is positioned forward of a front radiator <NUM>, which is arranged forward of an engine <NUM> within the engine compartment <NUM>. Horizontal arrows show the direction of airflow through the primary front opening <NUM>, as well as past the front closing cross-member <NUM>, to impinge on the front radiator <NUM>.

<FIG> is a side cross-sectional view of a portion of the front closing cross-member <NUM> of <FIG>, with superimposed streamlines showing a laminar airflow wake downstream of the front closing cross-member <NUM>. The front closing cross-member <NUM> is generally symmetrical relative to a horizontal reference line <NUM>. As shown, superimposed streamlines show a laminar airflow wake downstream of the front closing cross-member <NUM>, without exhibiting a turbulent wake that would lead to localized low pressure regions.

Claim 1:
A front closing cross-member (<NUM>) for a road vehicle, the front closing cross-member comprising:
left and right end portions (46A, 46B); and
a medial portion (<NUM>) having a leading edge (<NUM>), a trailing edge (<NUM>) that extends rearward in a longitudinal direction relative to the leading edge (<NUM>), and an airfoil-like cross-sectional shape, wherein the trailing edge (<NUM>) has a height less than a height of the leading edge (<NUM>), and the medial portion (<NUM>) is arranged between the left and right end portions (46A, 46B);
characterized in that:
each of the left and right end portions (46A, 46B) has a rounded, generally rectangular shape and a height greater than a maximum height of the medial portion (<NUM>), each of the left and right end portions (46A, 46B) defines a plurality of apertures (52A, 52B) extending in the longitudinal direction, and each aperture (52A, 52B) of the plurality of apertures (52A, 52B) is configured to receive a fastener arranged to couple each of the left and right end portions (46A, 46B) to at least a portion of a structural frame of the road vehicle, wherein for each end portion (46A, 46B) of the left and right end portions (46A, 46B), the plurality of apertures (52A, 52B) defines at least three apertures (52A, 52B) that are vertically aligned, with central axes of the apertures (52A, 52B) being parallel to one another.