GB2529675A

GB2529675A - Adjustable Fairing For A Road Vehicle

Info

Publication number: GB2529675A
Application number: GB1415264.9A
Authority: GB
Inventors: Rakesh Mistra; Suman Pradan; Andy Bacon
Original assignee: University of Huddersfield
Current assignee: University of Huddersfield
Priority date: 2014-08-28
Filing date: 2014-08-28
Publication date: 2016-03-02
Anticipated expiration: 2034-08-28
Also published as: GB2529675B; GB201415264D0

Abstract

A road vehicle 10 including a tractor 12 for pulling a trailer 14, and a trailer arranged to be pulled by the tractor where the trailer has a cab unit 16 and a cab top adjustable fairing 50. The adjustable fairing includes a deflector moveable between a raised position (figure 2) and a lowered position, an adjustment mechanism (60 figure 3) for moving the deflector between said raised and lowered positions, a control system for controlling the adjustment mechanism, and a pressure sensor 56 for determining the air speed in front of the adjustable fairing. Where the control system monitors signals from the pressure sensor, and determines whether to adjust the position of the deflector. A height sensor (20) may also be provided so that the height of the deflector relative to the trailer can also be determined. The pressure sensor may comprise an air pressure probe with a plurality of inlets at a distal end thereof. A method of automatically adjusting the deflector is also described, with the intention of providing a more aerodynamic profile for the vehicle and thus improving fuel efficiency.

Description

Adjustable Fairing for a Road Vehicle

FIELD OF THE INVENTION

The present invention relates to an adjustable fairing for a road vehicle.

BACKGROUND OF THE INVENTION

Many conventional road haulage vehicles include a fairing provided at the top of the cab of the vehicle. In most cases, the cab top fairing is essentially a fixed item, and so defines a set aerodynamic profile.

Adjustable cab top fairings are known, wherein the aerodynamic profile of the fairing can be altered. In practice, these are seldom adjusted and therefore fuel efficiency can be compromised. Adjustable cab top fairings are also known which use vehicle road speed to determine the fairing adjustment. However, such road speed systems are not very accurate, since they cannot account for changes in wind speed, for example.

Hence, there is a need to provide improvements in the aerodynamic performance of cab top fairings.

SUMMARY OF THE INVENTION

A first aspect of the present invention provides a road vehicle with an adjustable fairing, as set forth in daim 1.

A second aspect of the present invention provides a method of automatically adjusting a fairing on a road vehicle, as set forth in claim 16.

The present invention is advantageous because it allows for automated adjustment of the fairing when the vehicle is in motion. Active monitoring of air speed leads to enhanced fuel efficiency. This is of particular benefit at high vehicle speeds, where the need for good aerodynamic performance is most needed in order to maximise fuel economy.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be descr bed with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a road vehicle with an air deflection system; Figure 2 is a perspective view of the road vehicle of Figure 1 with a raised air deflection system; Figure 3 is a side, cutaway schematic view of the air deflection system of Figure 1; and Figure 4 is an exploded isometric view of the air deflection system of Figure 1.

DETAILED DESCRIPTION OF EMBODIMENT(S)

Referring firstly to Figures and 2, a road vehicle is indicated generally at 10, the road vehicle including a front unit or tractor 12 and a rear unit or trailer 14, wherein the tractor 12 is configured for pulling the trailer 14. The tractor 12 has a cab 16 in which the driver seat and controls are located. The cab 16 is provided with an air dam 30, side vanes 40 and an adjustable fairing 50.

The adjustable fairing 50 is mounted on the top 18 of the cab 16. As will be described in more detail below, the adjustable fairing 50 is adjustable between a lowered condition and a raised condition (as can he seen from Figures 1 and 2 respectively), in order to improve aerodynamic performance of the road vehicle 10.

Referring to Figure 3, the adjustable fairing 50 includes a base unit 52, which is secured to the top 18 of the cab 16. The adjustable fairing 50 further includes a deflector 54 having an upper surface over which air is intended to pass during forward motion of the tractor 10. The deflector 54 is adjustable relative to the base unit 52, in order to alter the aerodynamic profile of the fairing 50. More particularly, the deflector 54 is pivotally connected to the base unit 52, via a pivotal connection (not shown) between the deflector 54 and the base unit 52 at a location towards the front of the adjustable lairing so that the height of the upper surface of the deflector can he raised and lowered.

The adjustable fairing 50 includes an adjustment mechanism, indicated generally at 60. The adjustment mechanism 60 is operable for adjusting the position of the deflector 54. via a contr& system (not shown).

The adjustable fairing 50 further includes two sensors 20 and 56. Sensor 20 is mounted on the deflector 54 and is configured for determining the height of the trailer.

and is hereinafter referred to as the height sensor'.

The height sensor 20 is an ultrasound sensor which is secured to the rear surface of and proximate the upper point of the deflector. This sensor 20 uses ultrasound in order to detect the height of the trailer 14. for example by sending out an ultrasound signal towards the front face of the trailer 14 to rcbound off said front face. If no rebound signal is received by the sensor 20 then the top of the deflector 54 is higher than the trailer 14 and a signal is sent to the control system to adjust the heighi of the deflector to align with the hcight of the trailcr 14 (e.g. downwards).

Sensor 56 is an air pressure probe in the form of an elongate tube 57 and is hereinafter referred to as the pressure sensor'. The tube 57 extends through an aperture in the surface of the deflector 54, so that a free end of the tube 57 protrudes from the deflector 54. The prcssurc sensor 56 has fivc air inlets (not shown) located at the free end of the tube 57. This configuration allows the pressure sensor 56 to measure the air characteristics directly in front of the deflector 54.

The pressure sensor 56 allows for the simultaneous measurement of velocity, yaw angle and pitch angle of the air. In aliernative embodiments, the pressure sensor 56 may be in the form of a three-hole probe for the measurement the velocity and yaw angle of the air.

The pressure sensor 56 works by determining the direction and rate of pressure changes at the inlets of the tube 57. The multiple inlets of the pressure sensor 56 enable the measuring of pressures or pressure differences over the array of inlets, which allows for the calculation of the speed and direction of the air in close proximity to the deflector, i.e. directly in front of the deflector. This configuration allows for a more efficient and direct measurement of the speed and direction of the air in front of the deflector using a single sensor. This sensor configuration also removes the need for the control system to receive a further signal indicative of vehicle speed.

Refening to Figure 4. the adjustment mechanism 60 is shown in more detail. As can he seen, the adjustment mechanism 60 is a simple push-pull mechanism in the form of S a linear actuator 66 with a spindle arm 65. The adjustment mechanism 60 includes two arms 76, 78 which are secured via a bracket 62 to the deflector 54 and base unit 52 respectively. The two arms 76. 78 extend into (he space defined by the adjustable fairing and are connccted by a central pivot point 63 via connectors 64 to the end of the spindle 65 of the linear actuator 66.

The linear actuator 66 includes a motor 67 at one end which is parallel to and offset from the longitudinal axis of the spindle 65. The linear actuator is secured to the base unit 52, proximate the front region of the base unit, via a bracket 68 affixed proximate the motor 67.

The push-pull mechanism is moved between an open condition, in which the deflector 54 and base unit 52 are spaced apart (as illustrated in Figure 3), and a closed condition, in which the deflector 54 and base unit 52 are proximal one another, via a linear actuator 66. The single electric linear actuator 66 is controflable. via the control system, in order to change the condition of push-pull mechanism.

When in the open position, the arms 76, 78 aligned end-to-end are substantially parallel with each other to ensure the maximum separation between the colTesponding brackets 62 and as such between the deflector and the base unit 52. The linear actuator 66 extends or contracts to move from the open condition to the closed condition, this will pivot the arms 76, 78 away from their paraild configuration and reduce the separation between the deflector 54 and the base unit 52.

The adjustable fairing 50 is configured for automated adjustment during motion of the road vehicle 10. In particular, the control system for the fairing 50 is operational only when the ignition of the road vehicle 10 is switched on.

Upon turning on the ignition, the height sensor 20, pressure sensor 56 and contrcA system become active. As soon as the control system is activated, height sensor 20 detects the height of the trailer 14 and adjusts the deflector 54 so that the deflector is in the optimum position. When the road vehicle 10 is in forward motion, air flows through the pressure sensor 56. This allows the pressure sensor 56 to obtain a velocity vector of the air (velocity and direction) directly in front of thc dcficctor.

A signal corresponding to said sensor measurement is then sent to the control system: if the air speed measurement from the pressure sensor 56 is below a threshold value, the adjustment mechanism 60 remains inactive; if the air speed measurement from the pressure sensor 56 is above a threshold value, the adjustmcnt mechanism 60 become activated.

Once activated, the control system effects adjustment of the fairing 50, by activating the actuator 66, in other to push or pull the spindle 65 and so the connecting arms 76 in order to change the height of the deflector 54. The control system is programmed to reach a pit-determined deflector 54 height, dependent on the signal from the pressure sensor 56, e.g. by comparing the air speed measurement with a reference, in other to determine a desired deflector position for optimum aerodynamic performance. The control system is configured to obtain signals from the sensor on a periodic basis, and to operate the adjustment mechanism if a change in the trend of measurements is determined.

The presure sensor 56 provides the control system with information to adjust the height of the deflector dependent upon the air velocity in front of the deflector. When the height sensor 20 is used in combination with the pressure sensor 56 this allows the control system to produce highly accurate adjustments to the deflector which incorporate the height of the trailer that is attached. Thus the combination of sensors 20,56 allows for a highly accurate and automated adjustment of the deflector so as to minimise aerodynamic drag on the vehicle.

Although the embodiment illustrated in Figures 3 and 4 has a drive mechanism incorporating a linear actuator, other drive mechanism/arrangements are possible, e.g. in which the adjustment mechanism is in the form of a screw thread system Referring to Figure 5, an alternative embodiment of the adjustment mechanism, in the form of a scissor mechanism, is illustrated. As can be seen, the adjustment mechanism takes the form of a simple scissor mechanism, including two parallel horizontal elongate U channel beams, a lower beam 176 and an upper beam 177, and two links connected at a central pivot point 166. One end oleach link 180 is pivotally fixed with respect to an end of a respective beam 176, 177, and the other end of each link 80 S is coupled to the opposite end of a respective beam 176. 177. via a pin 172 located in a slot 178 in the beams 176, 177. In the illustrated embodiment, the pin 172 is made from nylon, although in alternative embodiments the pin could he made from any low friction material. The slots 178 run parallel to a long edge of the beams 176, 177 and are located proximate an end of the beams 176, 177.

The scissors mechanism 160 is moved between an open condition, in which the beams 176. 177 are spaced apart, and a closed condition, in which the beams 176, 177 are proximal one another, via a drive mechanism in the form of a motor driven screw which is connected to one of the links 180. A single electric motor 168 is controllable, via the control system (not shown), in order to change the condition of scissor mechanism. In the illustrated embodiment, the motor is mounted on the lowermost beam 176 and the screw extends generally parallel to the beam 176.

However, other mounting arrangements are possible, e.g. in which the screw is orthogonal to the beam 176.

The adjusting mechanism 160 includes two brackets 162 secured to the underside of the lowermost beam 176, for connection of the adjustment mechanism 160 to the base unit 152 of the fairing 150 at each end of the beam 176. The adjustment mechanism also includes two brackets 164 sccurcd to the uppermost beam 177. for connection of the adjusting mechanism 160 to the deflector 154 at each end of the beam 177. The configuration and location of the brackets 162, 164 can be varied to suit different makes and modds of tractor and fairing. Securing the adjustment mechathsm 160 to the deflector 154 at two points, proximate each side of the deflector provides greater stability of the deflector during movement of the vehicle.

Furthermore, providing the adjustment mechanism 160 with two adjusters, in the form of brackets 164, while using only a single actuator 168 provides a simple method of adjusting the adjustment mechanism 160.

Although the invention has been described above with reference to one or more preferred embodiments, it will be appreciated that various changes or modifications may he made without departing from the scope ol the invention as delined in the appended claims.

Claims

Claims 1. A road vehicle comprising a tractor for pulling a trailer, wherein the tractor compnses a cab having a cab top fairing. wherein the fairing includes a deflector having an upper surface over which air is intended to pass during 5!hrward movement ol the tractor, and wherein the deflector is moveable between a raised position and a lowered position. in order to change the orientation of said upper surface; further wherein an adjustment mechanism is provided for moving the deflector hetween said raised and thwered positions, and a control system is provided for controlling the adjustment mechanism; wherein the contr& system includes an pressure sensor for monitoring air speed; and further wherein the control system is configured to monitor signals from the pressure sensor, and determine whether to adjust the position of the deflector between said raised and lowered positions dependent on said signa's.
2. A road vehide according to claim I, wherein the pressure sensor is configured to provide a single point measurement of the air speed and air direction in front of the deflector.
3. A road vehicle according to claim 1 or claim 2, wherein the pressure sensor is an air pressure prohe comprising a plurality of inlets at a distal end thereof, and wherein the distal end projects through the deflector so that said inlets are exposed to atmosphere in front of the deflector.
4. A road vehicle according to any preceding claim, further comprising a height sensor for determining the height of the trailer.
5. A road vehicle according to claim 4, wherein the height sensor is configured to send a signal to the contro' system to adjust the position of the deflector so as to align with the height of the trailer.
6. A road vehicle according to any preceding claim, wherein the height sensor is mounted on the deflector.
7. A road vehicle according to any preceding claim, wherein the control system is configured to activate the adjustment mechanism if the air speed is above a threshold value.
8. A road vehicle according to any preceding claim, where the tractor comprises an ignition and the control system is active only when the ignition is on.
9. A road vehicle according to any preceding claim, wherein the pressure sensor is configured to send a signal to the control system on a periodic basis.
10. A road vehicle according to any preceding claim, wherein the fairing further comprises a base unit mounted at the top of the cab, and wherein the deflector is pivotally connected to the base unit.
11. A road vehicle according to any preceding claim, wherein the adjustment mechanism comprises a single actuator for driving the deflector between raised and lowered positions.
12. A road vehicle according to claim 11. wherein the adjustment mechanism comprises a scissor mechanism.
13. A road vehicle according to claim 11 or claim 12, wherein the adjustment mechanism is secured to deflector in at least two locations.
14. A road vehicle according to claim 11, wherein the adjustment mechanism compnses a pull push mechanism.
15. A road vehicle according to claim 14, wherein the adjustment mechanism comprises a linear actuator.
16. A method for automatic adjustment of a fairing on the cab of a road vehicle, the fairing including a deflector having an upper surface over which air is intended to pass during forward movement of the vehicle, the method comprising the steps of: a. activating a height sensor, an pressure sensor and a control system when the vehicle ignition is turned on; b. using the height sensor to determine the height of a trailer of the vehicle; c. sending a signal to the control system to adjust the height of the deflector so as to align with the height of the trailer; d. using the pressure sensor to determine if air speed is above a threshold value; e. using said pressure sensor to determine a single point, multi directional measurement of the air speed and air direction in front of the deflector; f. comparing the air speed measurement of step e) to a reference to determine optimum deflector position for aerodynamic performance; g. sending a signal to the control system to adjust the deflector if the air speed is above a threshold value; h. sending a signal from the pressure sensor to the control system periodically relating to the air speed measurement of step e); i. adjusting the height of the deflector dependent on the outcome of step h).