Soap bubbles may soon improve cars fuel efficiency

[sukishan]

Engineers at automotive research consultants Mira in Nuneaton, UK, are developing a system that uses soap bubbles filled with helium to improve the fuel efficiency of future cars.

London, Aug 31 : Engineers at automotive research consultants Mira in Nuneaton, UK, are developing a system that uses soap bubbles filled with helium to improve the fuel efficiency of future cars.

The 3-millimetre bubbles swirl around cars in a wind tunnel, and the engineers use 12 cameras to track the bubbles, thus capturing air flows in unprecedented detail.

The helium in the bubbles gives them neutral buoyancy-left to their own devices they will neither rise nor fall in the air, so any up or down movement can be attributed to air flow around the car.

"There aren't any tools in use today that can give such insight into what's going on in the fluid around a vehicle," New Scientist quoted aerodynamics specialist Angus Lock, the project leader, as saying.

He said that consumers are beginning to consider fuel economy and carbon emissions when choosing a new car, and thus aerodynamics has become much more important to car manufacturers.

He added that cutting a vehicle's air resistance is usually a cheaper way of improving those stats than reworking an entire engine or drivetrain.

The bubble technique has long been used to see how air moves around a structure, but the new camera system gives extra insight by capturing the precise movement of individual bubbles in 3D for later analysis and exploration.

Lock said that the full-scale wind tunnel tests remain the gold standard for looking at a car's aerodynamics, and it is simple to try out new ideas for improving streamlining by simply swapping parts of the car in the tunnel.

Sensors measure how the car interacts with the air rushing past.

"But they can't visualise the whole flow field around the vehicle, so you don't know what is behind those forces," said Lock.

The bubble-tracking approach captures the speed as well as the direction of air flow, which makes it more useful than existing tracking techniques such as injecting smoke trails around the car.

The infrared Vicon camera system is more usually found inside game or movie studios to capture the movements of actors wearing reflective markers, or in labs that study human motion.

The researchers push the cameras to their sensitivity limits to track light reflected from the bubbles instead.

"We are thinking about what we can do to the bubbles to make them easier for the cameras to see," said Lock.

They are considering building machine able to produce larger bubbles, which would have to be filled with a mixture of helium and air to achieve neutral buoyancy.

Other than that, they are planning a machine that can produce more bubbles.