Trailer Aerodynamics – An energy saver in transportation

The trailer can play an important role in saving energy according to WABCO. The technology company is addressing the physical and technical challenges of reducing air friction energy loss – one of the biggest causes of energy loss besides rolling resistance and braking energy.
These efforts aim to overcome the challenges that road transport fleet operators face when attempting to decarbonise long-haul operations. How do you grow a logistics network without increasing emissions? In light of the Paris Agreement within the United Nations Framework Convention on climate change, dealing with greenhouse-gas emissions mitigation, transport businesses are investing in modern equipment and the latest innovations to reduce their carbon footprint.

International call to action
With an emphasis on sustainability and cost effectiveness, WABCO’s suite of aerodynamics products are future-proofing fleet assets by  adapting them to environmental conditions following changes in legislation in selected markets such as the US, Canada, Europe and China.

With 25 years of composite material technology experience, WABCO has been prepared in the US with its aerodynamic portfolio before the legislation even existed. The TrailerSkirt and OptiFlow Tail are verified devices as per EPA’s voluntary SmartWay program. Furthermore, WABCO TrailerSkirt has been certified as a pre-approved device meeting the requirements of the California Air Resources Board (CARB) GHG 2 program. Even though not yet enforced, WABCO has been a strong supporter of the program’s challenging and more stringent requirements. This action will help fleets and companies to meet their internal and global CO2 emission targets.

In the meantime, Europe commenced emission tracking in 2019 to establish a reference baseline. This baseline, according to WABCO, will facilitate benchmarking on all emission improvements. A new regulation in November 2018 clarified the technical design specifications for rear aerodynamic solutions and type approval for devices such as OptiFlow AutoTail which automatically folds to avoid damages when a vehicle reverses into a loading dock area.

A specialist in aerodynamics
WABCO is a recognised expert in trailer aerodynamics and stands out in the market with its specialised engineering, design and testing procedures in this field. The implementation of aerospace knowledge into the trailer world has enabled the company to develop high performance aerodynamic solutions. Today, WABCO is consulted for its expertise and accurate assessment in performance gains. This is part of the reason why WABCO is involved in EU funded developments. As a technology company, WABCO starts aerodynamic product development by analysing major contributors of aerodynamic drag and by identifying opportunities for improvements. The engineers generate multiple alternatives to evaluate performance using Computational Fluid Dynamics analysis (CFD) which is used to calculate flow simulations with the assistance of computers. The resulting numerical simulations enable WABCO to preview and understand the interaction of air with the surfaces of its OptiFlow devices during product development phases. This allows WABCO to iterate different design ideas and to assess their impact on the drag coefficient so that only the ones with the best aerodynamic potential are prototyped and tested in a wind tunnel. WABCO claims the wind tunnel is a fundamental step of the development process as it enables to measure all air forces on a real physical prototype to test and verify its interaction under loads. This ensures that only the most promising aerodynamic devices are used for testing in real life environments, enabling WABCO to bring to market only those with proven fuel saving impact.

Raising the bar for aerodynamic product testing
WABCO’s aerodynamic solutions are not only submitted to WABCO’s standards but also to local regulations such as EC in Europe and CFR in the US. In Europe and China, for example, the SideWings and TrailerSkirts have a requirement to perform as sideguards, meaning that the device’s capability to withstand applied forces is certified. This is a certification process also known as a type approval.

In the US, WABCO builds trust in its solutions by performing rigorous climate and vibration tests. Vibration tests simulate extremely bad road conditions whereas climate tests prove the products can withstand temperatures ranging from -40 up to 65°C. These tests go as far as individual corrosion testing on all metal components. This enables WABCO to provide an up to five year warranty on its devices.

Champions in fuel efficiency
WABCO has expertise in satisfying various vehicle requirements and fleet needs, due to its suite of solutions, including: OptiFlow Tail, TrailerSkirt, SideWings and OptiFlow Nose Fairing. As there are a variety of trailer configurations, all WABCO products can be tailored to vehicle specification. Also, the TrailerSkirts and SideWings can be customised to accommodate different wheelbases.

A number of OEMs across North America and Europe now stock OptiFlow products as a standard aerodynamic optimisation for their trailer builds. With China now as a new target market, WABCO is looking forward to becoming a global aerodynamics partner for manufacturers and fleets.
Ji Hong, a leading cold chain equipment leasing company in China is willing to adopt greener technologies. “We have launched a TrailerSkirt pilot trial on our newest refrigerated trailers to assess the potential of WABCO aerodynamics devices towards CO2 reduction and fuel savings for our daily operations,” said Yin Lu, Marketing Manager at Ji Hong.

With more than 25 years of experience in North America, WABCO’s TrailerSkirt has successfully been adopted by the top operating fleets in the United States, Canada and Mexico.

Since its European launch in 2011, OptiFlow’s portfolio has also successfully gained support from fleets interested in both fuel savings and CO2 emission reduction.

Kai-Uwe Simon – Fleet and Workshop Manager of German wholesale bakery, Harry-Brot – shared his experiences with fitting WABCO OptiFlow SideWings to long-haul trailers: “In a before and after comparison, we evaluated the monthly average consumption of four trailers,” he said. “Here we compared the period January to June before the conversion with the values for the period January to June after the conversion. In this comparison, we were able to determine a consumption reduction of 1.9 litres per 100 km. This corresponds to a saving of 6.7 per cent.”
As a result of this operational testing, Simon is convinced of the positive properties of the WABCO wind deflectors.

In addition to realising fuel efficiency gains (of up to 9.5 per cent), Lukasz Puto, Manager of Transport Department at NoLimit in Warsaw, saw an opportunity to use the increased side surface of semi-trailers fitted with OptiFlow SideWings & Tail for promotional purposes. The business placed advertising graphics related to its ecological project, ‘Eco-Logistics – Less CO2’.

“Since the very beginning, NoLimit has been based on a comprehensive delivery of logistics solutions, focusing on the highest quality, safety, environmental protection and care of our employees,” Puto said. “In our company, the transport of goods is only part of the activity, but in this field, we wanted to be a leader, especially in the area of environmental protection and reduction of harmful carbon dioxide into the atmosphere. As part of the Eco-Logistics project, we use small trucks and vans powered by natural gas (CNG). However, in the long-distance multi-pallet transport, apart from operating modern trucks using Euro 6 compliant engines, we have also been fitting WABCO OptiFlow SideWings and Tail aerodynamic systems on our trailers since the beginning of 2017; thanks to them we have reduced CO2  emissions by about 50 tonnes per year.


Fast Fact
Thanks to its trailer aerodynamics solutions, WABCO continues to pioneer breakthrough electronic, mechanical and mechatronic technologies for braking, stability and transmission automation systems supplied to the world’s leading commercial truck, bus and trailer manufacturers.

Fast Fact

Engineers from different commercial truck and trailer industries are aiming towards a common goal: To lower CO2 output from 18 to 33 per cent as part of the Aeroflex Project, an EU funded research project. WABCO is a leading research partner in the aerodynamics trailer segment and engages in these scientific pursuits to push its testing technology prowess.

Fast Fact
In its quest to develop trailer solutions that maximise fuel efficiency, WABCO was awarded European Transport Award for Sustainability for its eTrailer solution last year. WABCO’s industry-leading eTrailer prototype uses an intelligent electric motor control to recuperate electric energy during braking, which can then be re-utilised to power the vehicle’s traction or to operate on board electric auxiliaries. Thomas Dieckmann, WABCO Technology and Innovation Officer, accepted the award on behalf of WABCO at the award ceremony held 21 November 2019 in Munich.

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