March 20, 2008 Driving in the rain on a motorway at speed is a hazardous endeavour as we all know, and perhaps the point when we all hold our breath most is in passing a heavy vehicle, with the spray obscuring our vision and the additional wind buffeting. Now, a British company has patented an innovation which has achieved a major reduction in spray obscuration – over and above the performance of existing mandatory spray suppression equipment.

The device, from Spraydown, will make its debut appearance at next month’s Commercial Vehicle Show in Birmingham in the United Kingdom. The new system has been granted full type approval under EU regulations.

In tests carried out and verified by Britain’s Transport Research Laboratory (TRL) at Crowthorne, Berkshire, vehicles equipped with Spraydown’s new technology air-water separation flap, achieved a reduction in drive-by obscuration of 43%, compared with existing systems. Spraydown’s system draws on leading edge vane design and technology, normally associated with high performance turbines in the aero engine and power generation industries.

The system comprises a rigid panel, made up of a series of fixed, vertical, lightweight, extruded vanes. Each vane incorporates three shaped channels which, when assembled in sequence, form a progressive series of water trapping gullies. The juxta-position and pitch of the vanes are also crucial.

Spray water within the wing and mudguard cavity on a commercial vehicle or trailer is drawn aerodynamically through the matrix of the Spraydown flap, where it is progressively scavenged, retarded and drained down the gullies almost to surface level, before discharging freely back onto the road surface.

The spray plume around the vehicle is also significantly reduced, lowered and controlled – and associated aerodynamics effectively draws the air swirl and excess water spray back within the vehicle envelope. Spraydown is now conducting additional tests on drag and fuel economy as the results of a Strathclyde University Flow Dynamic Modelling (FDM) programme suggest that the reduced drag performance could yield worthwhile fuel savings of over 2%.

A further spin-off of the new Spraydown system is that vehicle liveries – often regarded as important high profile media for corporate and brand visibility, stay much cleaner - and for longer in bad weather. Operator trials with a number of major fleets across the UK have been ongoing for several months. The product is to be marketed nationwide through Universal Components Limited of Sheffield, via its factor and distributor network.

Spraydown Managing Director, Steve Nesbitt says, “Improving visibility for following or passing motorists is about to take a step change – and that is important both for road safety and for the image of the road transport industry and its operators. If we can deliver the predicted reduced drag and fuel savings as well, then the adoption of our new technology spray suppression system will also make a contribution to the environment. Most of the current spray suppression devices date back to the original mandatory requirement in 1991. Traffic density, vehicle design, aerodynamics - and the performance and technology of composite materials have all moved on – and these factors have had a significant influence in the development of the Spraydown system.”

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