ravel at 70 mph on a motorway, and approximately 65 per cent of the
fuel you burn goes to overcoming aerodynamic drag. So even a slight
reduction in drag will significantly improve fuel consumption. This is
a particular problem for lorries and buses.
Kambiz Salari at the Lawrence Livermore National Laboratory
in California, US, and colleagues say that much of the drag from a
“bluff body” such as bus or truck comes from the air vortices generated
behind the vehicle as it moves. So instead of making these vehicles
more wedge-shaped, significant fuel economies can be made by modifying
Salari has designed a set of fans to be fitted to
the back of a cab or trailer that inject air into the air flow in a way
that significantly reduces the turbulence it generates. This should in
turn improve fuel economy, although the patent does not say the scale
of the potential gains.
Read the full fan-assisted truck patent application.
Justin Mullins, New Scientist consultant