Semi-trailer aerodynamic devices are devices affixed to semi-trailers, for the purpose of reducing aerodynamic drag caused by air turbulence. The two major types of device in use are trailer skirts (or side skirts), affixed to the underside of trailers, and trailer tails (or boat tails, or rear fairings), affixed to the rear. Several such devices have been recognized by the U.S. Environmental Protection Agency's SmartWay Transport Partnership, making them eligible for funding under the Diesel Emissions Reduction Act. [1]
Trailer skirts comprise a pair of panels affixed to the lower side edges of a trailer, running most of the length of the trailer and filling the gap between the forward and rear axles. Trailer skirts are typically constructed of aluminum, plastic, or fiberglass, with plastic the most resistant to damage from side or bottom impacts. [2] Skirts may have a modular design, allowing installation on a variety of trailer lengths. [3] Skirts generally weigh between 70 and 160 kg (150 and 350 lb). [4] Installation typically requires three to five person-hours. [4]
As of 2009 [update] , a set of trailer skirts cost between C$1500 and C$3000 (US$1300 to $2700). [4] Standard trailer skirts have an estimated payback period of ten to eighteen months, while "advanced" skirts (those that improve fuel efficiency by over 7%) are estimated to pay for themselves in seven to fourteen months. [4]
A 2012 investigation by SAE International of nine trailer skirt designs found that three provided fuel savings greater than 5%, and four provided savings between 4% and 5%, compared with an unmodified trailer. [5] Skirts with reduced ground clearance offer greater fuel savings; in one instance, reducing ground clearance from 16 in (41 cm) to 8 in (20 cm) resulted in an improvement in fuel savings from 4% to 7%. [2] One 2008 Delft University of Technology study found fuel savings of up to 15% for the particular design studied. [6] Sean Graham, president of a major supplier of trailer skirts, estimates that in typical use, drivers see fuel savings of 5% to 6%. [2]
Trailers with skirts fitted have also demonstrated reduced tire spray, and drivers have reported improved stability in crosswinds. [4]
As of 2018, over 60% of new trailers produced in Australia are equipped with skirts, whereas the figure is over 50% for the North American market.
A 2014 study by the North American Council for Freight Efficiency on adoption of fuel efficient technologies and practices found trailer skirts to be the most widely adopted technology of those studied, having been adopted by seven of the ten major shipping fleets in the study. [7]
Since the wide adoption of trailer skirts, incidents of them becoming detached and colliding with other vehicles have increased. On October 18, 2018, a trailer skirt came off of a tractor trailer traveling East in Knoxville, Tennessee and hit a westbound car, killing its driver. [8] [9]
Trailer tails, boat tails, or rear fairings comprise a set of panels, usually collapsible, which fold out from the rear of the trailer, creating a tapered shape that reduces drag from the low-pressure wake created behind the trailer. Trailer tails alone have demonstrated a fuel savings of 1%–5%, and in concert with trailer skirts, 9% improvement has been demonstrated. [10]
TrailerTail is a registered trademark of STEMCO. [11] [12]
At least one model of trailer tail, trade named TrailerTail, is part of Navistar's SuperTruck project, [13] which will use $37 million of US Department of Energy grants to build next generation trucks and tractor trailers.
A semi-trailer truck, is the combination of a tractor unit and one or more semi-trailers to carry freight. A semi-trailer attaches to the tractor with a type of hitch called a fifth wheel.
Automotive aerodynamics is the study of the aerodynamics of road vehicles. Its main goals are reducing drag and wind noise, minimizing noise emission, and preventing undesired lift forces and other causes of aerodynamic instability at high speeds. Air is also considered a fluid in this case. For some classes of racing vehicles, it may also be important to produce downforce to improve traction and thus cornering abilities.
Wingtip devices are intended to improve the efficiency of fixed-wing aircraft by reducing drag. Although there are several types of wing tip devices which function in different manners, their intended effect is always to reduce an aircraft's drag. Wingtip devices can also improve aircraft handling characteristics and enhance safety for following aircraft. Such devices increase the effective aspect ratio of a wing without greatly increasing the wingspan. Extending the span would lower lift-induced drag, but would increase parasitic drag and would require boosting the strength and weight of the wing. At some point, there is no net benefit from further increased span. There may also be operational considerations that limit the allowable wingspan.
A slipstream is a region behind a moving object in which a wake of fluid is moving at velocities comparable to that of the moving object, relative to the ambient fluid through which the object is moving. The term slipstream also applies to the similar region adjacent to an object with a fluid moving around it. "Slipstreaming" or "drafting" works because of the relative motion of the fluid in the slipstream.
A blind spot in a vehicle or vehicle blind spot is an area around the vehicle that cannot be directly seen by the driver while at the controls, under existing circumstances. In transport, driver visibility is the maximum distance at which the driver of a vehicle can see and identify prominent objects around the vehicle. Visibility is primarily determined by weather conditions and by a vehicle's design. The parts of a vehicle that influence visibility include the windshield, the dashboard and the pillars. Good driver visibility is essential to safe road traffic.
A Kammback—also known as a Kamm tail or K-tail—is an automotive styling feature wherein the rear of the car slopes downwards before being abruptly cut off with a vertical or near-vertical surface. A Kammback reduces aerodynamic drag, thus improving efficiency and reducing fuel consumption, while maintaining a practical shape for a vehicle.
In aeronautical and naval engineering, pusher configuration is the term used to describe a drivetrain of air- or watercraft with propulsion device(s) after the engine(s). This is in contrast to the more conventional tractor configuration, which places them in front.
Drafting or slipstreaming is an aerodynamic technique where two moving objects are aligning in a close group to exploit the lead object's slipstream and thus reduce the overall effect of drag. Especially when high speeds are involved, as in motor racing and cycling, drafting can significantly reduce the paceline's average energy expenditure and can even slightly reduce the energy expenditure of the lead vehicle.
A spoiler is an automotive aerodynamic device whose intended design function is to 'spoil' unfavorable air movement across the body of a vehicle in motion, usually manifested as lift, turbulence, or drag. Spoilers on the front of a vehicle are often called air dams. Spoilers are often fitted to race and high-performance sports cars, although they have become common on passenger vehicles as well. Spoilers are added to cars primarily for styling purposes and either have little aerodynamic benefit or even worsen the aerodynamics.
A mudflap or mud guard is used in combination with the vehicle fender to protect the vehicle, passengers, other vehicles, and pedestrians from mud and other flying debris thrown into the air by the rotating tire. A mudflap is typically made from a flexible material such as rubber that is not easily damaged by contact with flying debris, the tire, or the road surface.
The SmartWay Transport Partnership is a business organization administered by the United States government and designed to encourage businesses to manage logistics in an environmentally responsible way. The program was formed in 2004, and is administered by the United States Environmental Protection Agency (USEPA) and is housed with the USEPA's Office of Transportation and Air Quality (OTAQ) - Transportation and Climate Division (TCD). SmartWay aims to voluntarily achieve improved fuel efficiency and reduce environmental impacts from freight transport. SmartWay currently has approximately 600 member businesses, membership is voluntary. The organization provides incentives and recognition for top performers to encourage continued improvement.
Boat tail may refer to:
Energy-efficient driving techniques are used by drivers who wish to reduce their fuel consumption, and thus maximize fuel efficiency. Many drivers have the potential to improve their fuel efficiency significantly. Simple things such as keeping tires properly inflated, having a vehicle well-maintained and avoiding idling can dramatically improve fuel efficiency. Careful use of acceleration and deceleration and especially limiting use of high speeds helps efficiency. The use of multiple such techniques is called "hypermiling".
The KenworthT600 is a model line of conventional-cab trucks that were produced by the American truck manufacturer Kenworth from 1984 to 2007. Distinguished by its aerodynamic sloped hood, the T600 was a Class 8 truck, typically sold in semitractor configuration.
ECOnetic was a tradename for certain car models produced by Ford of Europe, introduced in 2008, consisting of one model in each of the Fiesta, the Focus and the Mondeo range, with an emphasis on higher fuel efficiency and low-CO2 emissions.
The International ProStar is a line of Class 8 trucks that was manufactured by Navistar International from 2006 to 2017. Marking the introduction of the "-Star" branding nomenclature to International, the conventional-cab ProStar replaced the 9400i. Competing against the Freightliner Cascadia and the Kenworth T2000/Peterbilt 387, the ProStar was an aerodynamically-enhanced conventional.
A teardrop trailer is an aerodynamically shaped semi-trailer with a curved-roof that differs in shape from the traditional rectangularly shaped trailer. The trailer is meant to be paired with a compatibly designed tractor unit leading to greater fuel efficiency of the tractor-trailer combination. As such, the "teardrop" phrase refers to the entire combination, not just the trailer. The curved shape of the roof decreases aerodynamic drag by smoothing airflow over the top, thus improving fuel efficiency.
The fuel economy in aircraft is the measure of the transport energy efficiency of aircraft. Fuel efficiency is increased with better aerodynamics and by reducing weight, and with improved engine brake-specific fuel consumption and propulsive efficiency or thrust-specific fuel consumption. Endurance and range can be maximized with the optimum airspeed, and economy is better at optimum altitudes, usually higher. An airline efficiency depends on its fleet fuel burn, seating density, air cargo and passenger load factor, while operational procedures like maintenance and routing can save fuel.
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