Improving Productivity And Sustainability Through Aerodynamic Performance Of Vehicles

History of aerodynamics in racing car industry

Discuss about the Improving Productivity and Sustainability.

Aerodynamic performance of a vehicle depends on several factors such as the design of the vehicle (including all its components), amount and position of the loads it is carrying, and external factors such as wind intensity and speed. This report focuses on the effect of amount and position of loads on a vehicle’s aerodynamic performance. To start with, it is important to understand what vehicle aerodynamics is about. In general, vehicle aerodynamics entail the forces acting on the vehicle as it moves through the air. When a vehicle moves through air, it experiences some resistance Management known as drag. This resistance has significant impacts on how the vehicle: is handled/controlled, accelerates and attains fuel mileage (George, 2009). It is for this reason that vehicles nowadays designed by considering their aerodynamic performance. The key benefits of a vehicle with good aerodynamic performance are: improved safety, easy control, improved fuel mileage and efficiency, increased driver and passenger comfort and reduced carbon emissions (Hardin, 2007). This implies that aerodynamic performance affects each aspect of the vehicle’s use thus it is of great importance to be considered when designing a vehicle.     

The main goals and objectives of ensuring good aerodynamic performance of a vehicle is to minimize  drag, reduce noise, and prevent other factors that may result into aerodynamic instability, such as unwanted lift forces. There are five main forces that affect aerodynamic performance of a vehicle. These are: aerodynamic drag, aerodynamic lift, side force, bouncing (yawing movement), and rolling movement. Aerodynamic drag is the air resistance created when the vehicle moves through the air. This force acts in the opposite direction to the motion of the vehicle. Aerodynamic lift is the resultant force’s vertical component. It is caused by distribution of pressure over the vehicle body. It usually results from reduction of pressure between the tyre of the vehicle and the ground. Side force is the wheel imbalance created when the vehicle is negotiating a corner. Yawing movement is the vehicle body’s vertical movement. Rolling movement is the vehicle’s movement about the longitudinal axis. All these forces are directly or indirectly affected by the amount and position of the vehicle’s loads.

Study of aerodynamics has become very critical in the automobile industry as the need for improved fuel efficiency and vehicle performance increases. Manufacturers of race cars are among those that take vehicle aerodynamics very seriously because this is what gives them an advantage over their competitors. If a race car is designed considering all the important factors related to aerodynamics then it will be able to race at the highest speed possible leaving its competitors far behind.

Advantages of improved aerodynamics performance of vehicles

From early 20^th century and backwards, most designers of racecars were focused on creating streamlined bodies and reduced frontal areas so as to minimize drag (George, 2014; Niedermeyer, 2010). As a result of this, they were able to create cars that raced at very high speeds with no extra engine power. However, study and integration of aerodynamic factors in the design and manufacturing of racecars was very slow in the early days mainly because of inadequate funding. Research and development projects related to this were very minimal, leaving designers to rely mainly on trial and error or their experience. Another challenge was that the streamlined bodies of racecars increased their weights resulting to handling difficulties Management. Drivers found it very difficult to control the cars especially when negotiating corners at high speeds. One of the reasons behind this instability was pressure imbalance between the front and rear ends. Moving at high speeds caused pressure reduction on top of the car, which causes the rear end to lift. This caused rapid over-steering of the car. These challenges drove designers and engineers to start developing designs that lowered the cars’ center of gravity and with improved handling even at greater speeds.

It was until 1960s that things started changing completely when racecar designers focused on how to improve aerodynamics performance of cars by considering both drag and lift. It was then that aerodynamics components started being incorporated in the racecars’ bodyworks (Rapid-Racer.com, 2016). Since then, numerous developments have been made in relation to improving aerodynamics performance.

Today, aerodynamics is a very important element in vehicle design. In fact, all vehicles nowadays are designed by putting in mind factors that affect aerodynamics. This is mainly because of the potential advantages, which include the following:

Safety is always the top priority in vehicle design and manufacturing. Aerodynamics help designers to determine the right shape, size and type of vehicle components, and where and how they should be joined to create the complete product. Using aerodynamics, designers are able to determine the right weight limits that the vehicle can carry and how the weights should be distributed. It also helps in establishing the appropriate components that can be added on the vehicle to improve its aerodynamics performance. Such components include wind deflectors installed on roofs of trucks or caravans to deflect wind away from the vehicles (Lord, 2015).The concept of aerodynamics is also applied in improving safety of double deck buses. The load compartments of these busses are at the lowest points so as to lower their centre of gravity. The upper decks are also not allowed to be overloaded at any given time so as to reduce the height of weight or load that helps in reducing chances of toppling. All these improve aerodynamic performance of vehicles.

Improved fuel mileage and efficiency

This is a major advantage of vehicles with improved aerodynamic performance. The loads of these vehicles are appropriately distributed at all points, which makes it easier for the driver to accelerate, decelerate, brake, or negotiate a corner. With proper aerodynamics, the vehicle does not topple easily irrespective of how sharp the corner it. Chances of under-steering or over-steering are also greatly reduced. This advantage is very useful in the racing cars because drivers are able to negotiate very sharp corners without toppling. The same advantage is being capitalized in sports cars. In general, improved aerodynamics helps the driver to be in control of the vehicle at all times.

Vehicles with greater aerodynamic performance have higher fuel mileage and efficiency because of several reasons. First and foremost, the vehicles experience very minimal resistance between the tyres and the road. This enables the vehicles to move faster and easily. Second, the vehicles have great traction due to proper distribution of loads across all axles. Third, they experience less drag thus minimal power is needed to push them through the air. When these three factors are combined, they result into vehicles that consume less fuel over longer distances than vehicles with low aerodynamic performance. 

Aerodynamics assist in designing vehicles that do not bounce or cause any discomfort, of drivers or passengers, when negotiating a corner. These vehicles turn without under-steering or over-steering, which make journeys comfortable irrespective of distance or meandering of roads. When the vehicle is negotiating a corner or when brakes are applied appropriately, there is no scattering of loads from one side to another because the loads are properly reduced. The comfort is also in terms of reduced noise level. Vehicles with improved aerodynamic perform have minimal noise levels regardless of the speed at which they are travelling. This is because the bodies of these vehicles are designed in a way that facilitates seamless flow of air around the top and sides of the vehicle thus minimizing the noise produced when the vehicle is moving through the air.

Carbon emissions are among the top factors affecting global warming. One of the leading sectors Management contributing to carbon emissions across the world is transportation. This has prompted researchers and designers to capitalize on potentials of aerodynamics to reduce carbon emissions from vehicles. These vehicles have higher fuel efficiency, which means that they use less fuel that is fully converted into power. Use of less fuel and higher conversion rate of the fuel into power means reduced carbon emissions. This is also facilitated by proper distribution of the loads they vehicle is carrying and ensuring that the loads are within acceptable legal limits. Therefore aerodynamics is being used to make vehicles cleaner by improving their fuel efficiency.

Drivers and passengers always want to reach their destinations faster but safely. The former is usually achieved if the vehicle is able to travel at higher speeds, without compromising the safety of drivers, passengers and even goods being transported. Aerodynamics helps in designing vehicles that experience very minimal air resistance (drag) thus they are able to move at greater speeds. For instance, today’s racing cars are also able to travel at supersonic speeds mainly because of improved aerodynamic performance. When all factors affecting aerodynamics are considered in design of vehicles, the final products are those that experience less air and road resistance. If these resistances are reduced, it means that vehicles are able to travel faster.

Aerodynamics performance of a vehicle is influenced by a wide range of factors. Load is one of these factors. The elements of load that affect aerodynamics is amount of the load and the position of the loads in the vehicle. To optimize the advantages of aerodynamics, the total amount of load carried by the vehicle must be within the set legal limits by the manufacturer and the state or country. In addition, the load should be properly distribution in the vehicle to prevent toppling or difficulties in controlling the vehicle. Therefore some of the factors that affect aerodynamic performance of vehicles are as follows:

The amount and position of loads largely affects the stability and aerodynamic performance of the vehicle because they determine its centre of gravity. The centre of gravity of the vehicle should be as low as possible. This is why most heavy components of the vehicle such as the engine, suspension and load compartments are at lowest points of the vehicle (Woodford, 2016). For example, double-deck buses are not allowed to carry extra passengers on the upper deck. This is because if the upper deck carries extra passengers, the bus’ centre of gravity will be raise thus making it more unstable especially when negotiating a corner (Francois et al., 2009; TutorVista.com, 2017). Nevertheless, these buses are also designed to ensure that they do not topple even if the lower deck is empty while the upper deck is full of passengers (Gibbs, 2016). Thus in order to maintain the centre of gravity of the vehicle as low as possible and improve the vehicle’s aerodynamic performance, most loads must be at the lower points of the vehicle (Whiting and Rugg, 2012).

Balancing is a very important factor when carrying loads in a vehicle. The loads must be evenly distributed to prevent imbalance that can make it difficult to control the vehicle. If more loads are on one side of the vehicle, it is likely to incline towards that side. This makes the vehicle susceptible to losing balance and toppling if it gets pushed by a very slight force. Thus when loading the vehicle, the loads have to be balanced properly. If some loads are removed along the journey, the remaining loads should also be rearranged to ensure appropriate balancing (Cottingham, 2017; Land Transport Safety Authority, (n.d.)). The load should also be appropriately distributed between the front and back areas. No load should be more at either the front or back of the vehicle, beyond recommended ranges. When too much weight is subjected on the steering wheels, steering becomes very difficult leaving the driver unable to control the vehicle. This excess load can also damage the steeling tyres and axle. When the front axles are underloaded, may be because of most loads bin shifted to the rear of the vehicle, the weight of the steering axle becomes too light for safe steering. When the driving wheels have too little weight, traction of the vehicle is likely to be poor. This can cause easy spinning of the drive wheels (TruckingTruth.com, (n.d.)). In general, excess loads at the front of the vehicle tends to cause under-steering while excess loads at the rear of the vehicle causes over-steering. Under-steering occurs when the turning or steering of the vehicle is more than it was commanded or intended by the driver, causing the vehicle to spin. Under-steering occurs when the turning or steering of the vehicle is less than it was commanded or intended by the driver, causing the vehicle to leave the road. These two can be avoided by determining the centre of mass of the vehicle.     

Proper load distribution of a vehicle requires accurate calculations of the total load supported by the vehicle so as to determine how well it should be distributed across the axles (Toner, 2011). This is usually done by the vehicle manufacturers and include the information in vehicle manuals (Weber, 2014).

Every country or state has legal weight limits for different categories of vehicles. The main reasons of setting this legal weight limits are to ensure that all vehicles carry loads that do not reduce their aerodynamic performance nor compromise their stability and safety, and that the vehicles do not overload and damage roads and bridges (Khan, Ayub and Qadir, 2014OECD, 2011). Legal weight limits include maximums for axle weights, tyre loads, gross combination weights, gross vehicle weights, etc. An overloaded vehicle is very difficult to steer, control its speed or brake. When a vehicle is overloaded, it has to move at a very low speed on upgrades, which increases its aerodynamic drag. These speed of these vehicles can also increase rapidly and uncontrollably when moving downgrades. When this happens, it becomes difficult for the driver to control the vehicle and it can easily overturn or topple.

Most people tend to focus only on the maximum amount that the vehicle should carry forgetting about the minimum loads. Underloading is as dangerous as overloading. This is because an underloaded vehicle cannot generate enough downward force to overcome lift that could otherwise make the vehicle airborne. However, the downward force also increases drag, which limits the vehicle’s speed and increases its fuel consumption (Lucas, 2014). Addition of downward forces increases the total amount of vertical load acting on tyres. This means that the driver has to use more power to accelerate and brake the added load, which reduces speed of the vehicle. On the other hand, the additional downward force improves the concerning performance of the vehicle without having great impact on other areas of the vehicle’s performance. To optimize aerodynamic performance of a vehicle, drag should be minimized and downward force should be increased up to recommended limits (Beeton, 2012). In other words, aerodynamics should be used to ensure proper balancing between drag, lift and downward force to maximize vehicle performance.

Therefore improving aerodynamic performance of a vehicle is desirable because it has the potential to save engine power, reduce fuel consumption and emissions, improve stability & safety of the vehicle, and increase speed. It is important to determine and analyze all factors influencing aerodynamics of the vehicle such as drag, lift and downward force so as to identify the most suitable quantity of loads that the vehicle should carry and how to position them appropriately. 

References

Beeton, S. (2012) Introduction to Race Car Aerodynamics [Online]. Available: https://www.worldtimeattack.com/index.php/introduction-to-race-car-aerodynamics/ [Accessed May 3, 2017].

Cottingham, D. (2017) Carrying loads on a car, motorbike or trailer [Online]. Available: https://www.drivingtests.co.nz/resources/carrying-loads-on-a-car-motorbike-or-trailer/ [Accessed May 2, 2017].

Francois, D.G., Delnero, J.S., Colman, J., Maranon, L.J., and Camocardi, M.E. (2009) Experimental determination of stationary aerodynamics loads on a double deck bus. 11^th Americas Conference on Wind Engineering, June 22-26, 2009, San Juan, Puerto Rico.

George, A. (2014) The Bizarre Germany Car that was Ultra-Aerodynamic and totally impractical [Online]. Available: https://www.wired.com/2014/09/german-aerodynamic/ [Accessed May 3, 2017].

George, P.E. (2009) How Aerodynamics Work [Online] HowStuffWorks. Available: https://auto.howstuffworks.com/fuel-efficiency/fuel-economy/aerodynamics.htm [Accessed May 2, 2017]. 

Gibbs, K. (2016) Stability [Online]. Available: https://www.schoolphysics.co.uk/age11-14/Mechanics/Statics/text/Stability_/index.html [Accessed May 2, 2017].

Hardin, D. (2007) Car Aerodynamics – all about aerodynamics [Online]. Available: https://www.superstreetonline.com/how-to/paint-body/130-0612-car-aerodynamics-tech/ [Accessed May 2, 2017].

Khan, S.U., Ayub, T. and Qadir, A. (2014) Effect of overloaded vehicles on the performance of highway bridge girder: a case study. Procedia Engineering, 77(2014), pp. 95-105.

Land Transport Safety Authority (n.d.) Heavy vehicle stability guide. Wellington, New Zealand: Land Transport Safety Authority.

Lord, P. (2015) How Important are RV Aerodynamics? [Online]. Available: https://www.tradervs.com.au/features/1505/how-important-are-rv-aerodynamics [Accessed May 3, 2017].

Lucas, J. (2014) What is aerodynamics? [Online]. Available: https://www.livescience.com/47930-what-is-aerodynamics.html [Accessed May 3, 2017].

Niedermeyer, P. (2010) An illustrated history of automotive aerodynamics – in three parts [Online]. Available: https://www.thetruthaboutcars.com/2010/02/an-illustrated-history-of-automotive-aerodynamics-in-three-parts/ [Accessed May 2, 2017].

Organization for Economic Co-operation and Development (OECD) (2011) ITF Research Reports Moving Freight with Better Trucks Improving Safety, Productivity and Sustainability: Improving Safety, productivity and Sustainability. Paris, France: OECD Publishing.

Rapid-Racer.com (2016) Aerodynamics [Online]. Available: https://www.rapid-racer.com/aerodynamics.php [Accessed May 2, 2017].

Toner, R. (2011) Calculating commercial vehicle weight distribution & payload made easy [Online]. Available: https://www.worktruckonline.com/channel/safety-accident-management/article/story/2011/09/calculating-commercial-vehicle-weight-distribution-payload-made-easy.aspx [Accessed May 2, 2017].

TruckingTruth.com (n.d.) Transporting Cargo Safely [Online]. Available: https://www.truckingtruth.com/cdl-training-program/page34 [Accessed May 2, 2017].

TutorVista.com (2017) Equilibrium and Stability [Online]. Available: https://www.tutorvista.com/content/physics/physics-i/forces/equilibrium-and-stability.php [Accessed May 2, 2017].