Air drag reduction in buses using side air channel diverters

Abstract

Our invention introduces air channels in the front of the bus to reduce air drag by decreasing the pressure built up on the front side of a bus by providing an escape route to the sides through channels. The two opening of channels in front of the bus are placed below the windshield which usually has high pressure build up. The cross section along its length of the two air channels has a small convergent section and large divergent to allow the air to expand to the low pressure on the sides of the bus producing draft effect which sucks the air from the front of the bus. The above modifications based on their size and shape will reduces drag from 0.7 to 0.53 and an additional modification of the bus body at the rear would reduce the air drag to as low as 0.36. Novelty of the invention is mainly with regard to the air channels provided at the front of the vehicle. The air drag is significant at higher speeds which would have resulted in higher fuel consumption without the modification suggested above. The modification suggested in the innovation will benefit any vehicle which has a box type of design such as bus and trucks.

Specification

Description:FIELD OF INVENTION
[001] This innovation relates to the field of aerodynamics of road vehicles, more specifically to reducing air drag of buses.
BACKGROUND AND PRIOR ART
[002] The invention is related to the domain of aerodynamics of intercity buses more specifically to modification in the bus body with introduction of air channels to reduce high pressure zones at the front end of buses. Most buses are built by bus body building workshops on the chassis provided by OEM's. Most bus body building workshops adopt standard body design which are aesthetically pleasing, functional with minimum attention given to aerodynamics. Cost of the bus body build matters for the owners of bus and benefits from aerodynamics are usually neglected. Most patents that have been published are limited to surface profiling at the front, rear of the bus and vortex generators, but none of the patents are related to reduction of air drag with air channel diverters making our invention novel in the field of aerodynamics. If aerodynamics modifications is done for large number of buses which run under transport corporation, transport fleet corporations, significant fuel savings can be made.
SUMMARY OF THE INVENTION
[003] Vehicles move through the air medium which offers resistive force against the vehicle motion called as air drag or aerodynamic drag. For a typical commercial vehicle such as bus or a truck, air drag at speeds beyond 60KMPH account for more than 50% of energy required to propel the vehicles forward. So even a small reduction in air drag would significantly reduce fuel consumption. Transport corporations can make a big saving even if improvements in air drag is small. Simulations have shown that, with the suggested modification of providing air channel at a distance of 3 meters from the front end of the bus, air drag can decrease by around 25% compared the conventional bus. With an additional modification of tapered body towards the rear end of the bus, the air drag will decrease by around 50% compared to the conventional bus body design. Comparison of coefficient of drag for conventional bus and bus with air channels and with tapering at the rear is shown in the table 1, which is the claim of our invention.
BRIEF DESCRIPTIONS OF DRAWINGS
[004] The following description of various embodiments of the invention shown below are for better understanding when read in conjunction with the attached drawings. however, that the invention is not limited to the specific embodiments disclosed in the drawing.
[005] The figure 1 shows the sketch of the proposed bus design along with the dimensions used for simulation.
[006] The figure 2 shows the internal details of both the air channel visible along with the outline of the body.
[007] The figure 3 shows the side view of the bus with internal details of the air channel
[008] The figure 4 shows the isometric view of the bus along with air channel shown only for one side.
[009] The figure 5 shows the isometric opaque view of the bus.
[010] The figure 6 shows the details of the modification.
DETAILED DESCRIPTION OF THE INVENTION
[011] Design inspiration came from nature, where the air channel can be compared gills of a fish, through which fish breathe taking in water through their mouths & pushing it out through their gills. The design includes two air channels at the front. The air channels are made by sheet metal supported on the chassis using L angle steel sections. Vehicle may need modifications to shift functional components to avoid interference with the air channel. Air channels shape along the flow may have to be changed based on the specific need of the vehicle but the concept of diverting air from high pressure to low pressure remains same. Air flows in through openings just below the wind shield, moves through the channel beneath the platform & then exits out the sides of the bus. Moreover, an addition of taper at the rear end of bus at the roof side and underbody would reduce the air drag by more than 50% when compared to 25% without taper. , C , Claims:[012] 1. The air channel openings at the front has a converging profile to efficiently capture the high-pressure air and then allow it to expand through a diverging section, guiding the air into the vehicle's low-pressure side zones. The lowering of the pressure at the front is a major contributing factor for the reduction of air drag.
[013] 2. The air channel opening is in line with the front body surface of the Bus. Channel dimensions can be customized to accommodate the size and design constraints of the specific vehicle. The number of air channels and their dimensions will change, based on the vehicle to which the system has to be built.
[014] 3. The location of side vents, dimensions along the path also contribute to reduction in air drag by providing a suction effect. This ensures that any pressure built on the front side of the bus is released to the low-pressure end on the sides of the bus.
[015] 4. The benefits of reduced air drag as per the modification suggested in the previous claims can be complemented by additional modification at the rear end of the bus. A tapering body on roof top and underbody made on the rear side of the body will allow the air stream to converge and act as diffusers, reducing the pressure drop behind the vehicle.
[016] 5. The terms bus, truck and vehicle, all refer to automobiles which have nearly a box type of design on the front side. Air channel design will vary with vehicles to avoid interference with functional components or Functional components of the vehicle will have to be moved to avoid interference with the air channel.
[017] 6. The Aerodynamic drag reduction modification suggested as a whole can decrease the aerodynamic drag of vehicles to almost 45%, reduction in air drag, 25% reduction to total resistive force. Due to this reduction in fuel consumption is around 20% which reduces the operating cost of the vehicle significantly.

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