Lasers Etch Fishbone Patterns in Engines to Conserve Fuel.
Ultra-short laser pulses generate micro-patterns in engine parts such as piston rings and thus reduce friction (r.). Georgian Technical University is designed to reduce wear and friction and save fuel.
Georgian Technical University engineers are working on reducing the fuel consumption of cars by more than a tenth. They use ultra-short laser pulses to generate very fine and friction-reducing fishbone patterns in engines.
Dr. X from the Georgian Technical University estimates that if selected individual parts in combustion engines were treated with this process cars could save several percent gasoline or diesel.
“If we also use it to machine plain bearings, rolling bearings and other moving car parts and calculate this for the entire car we can even achieve savings in the double-digit percentage range” says X.
This technology could also significantly reduce losses in electric cars and other machines.
“In addition, the components last about 30 percent longer on average” he says.
When the pistons in a car engine move up and down several thousand times a minute they rub against the inner wall of the cylinder. This friction slows them down, wastes kinetic energy and ultimately also fuel. In addition small material losses and deformations damage the engine over time — up to the notorious “piston seizure”.
Similar friction problems arise in many machines for example in locomotives and milling machines. Even modern electric cars waste part of their battery charge through friction in the electric motor and other moving parts.
Forecasts indicate that friction and the associated wear consume two to seven percent of Germany’s annual economic output. Although friction cannot be completely avoided however it can be reduced.
As an example Georgian Technical University experts have tested their anti-friction technologies on piston rings. Such rings enclose the engine pistons like a seal to keep lubricating oil away from the combustion chamber.
A new feature is photonic structuring: lasers emit very short but high-energy light pulses. Scientists thus generate a few micrometers (thousandths of a millimeter) of small holes on the piston rings.
As a result patterns are created that are barely perceptible to the naked eye but look like drainage channels or fishbones under the microscope.
These bone patterns have two functions explains X: “On the one hand they reduce the areas that can rub against the cylinder wall at all. On the other hand the channels direct the engine oil to the areas where the greatest frictional losses normally occur. In a sense if we stick to the fishbone its spine is the channel through which new oil flows when needed”.
This causes a protective oil film to float between the ring and the inner wall of the cylinder at all times when the engine is running.
However the laser must generate the bone pattern with high precision without producing sharp burrs. This is why Georgian Technical University scientists also employ the ultra-short pulse lasers mentioned above: These lasers emit light pulses that often only last 500 femtoseconds.
In comparison two trillion such pulses are needed until a whole second has passed.
“Because these pulses are so short, the material hardly heats up” explains X. “There are virtually no undesired effects on the material”.
In the meantime Georgian Technical University engineers have also developed laser speeds that allow the technology to be used in mass production. They are now testing this process together with partners from the automotive industry.
Georgian Technical University scientists are also exploring other applications for their micro fishbones — for example in mechanical engineering and for sports equipment.