Diesel engine pistons could borrow design cues from golf balls

Speed of Air is currently said to be concentrating on the commercialisation of its medium-duty engines. However, they could expand to offering petrol and racing engines.

Speed of Air - an engine technologies company is said to have come up with a new design for their pistons which could help diesel engines to reduce particulate filters while also improving efficiency and performance. According to a media report, Speed of Air (SoA) is said to have taken inspiration from golf balls and introduced diesel engine pistons with dimples.

Dimples on a golf ball create a boundary layer by producing small turbulences at the surface. This boundary layer is what helps the golf ball reduce drag & retain its speed; translating to a longer distance of travel compared to a smooth ball. Similarly, in a combustion chamber, the dimples create a boundary layer with the fluids, which helps keep the fuel in suspension with the air, which leads to a better air-fuel mixture for burning.

The company has been experimenting with different textured pistons for quite a long time, before concluding that the dimpled texture of a golf ball works best. Today the company relies on computational fluid dynamics (CFD) to optimise its designs before using them in Powerstroke, Duramax and Cummins engines for medium-duty vehicles. SoA has further improved the design by having pressure release slots machined into the crown of the piston, which helps accelerate the burn of the air-fuel mixture and offers a quieter running engine in the process.

To prove it's working, the company compared a stock Cummins 5.9-litre engine to one with its pistons installed. The result was that the engine with SoA's dimpled pistons produced 15.5% more horsepower and a 15.2% rise in torque. The reports also stated that brake-specific fuel consumption was reduced by 3.2%, the opacity of exhaust dropped by 77.6%, NOx levels went down by 61%, exhaust hydrocarbons dropped by 32.5%, and CO2 levels were cut down by 41.4%.

Speed of Air is currently said to be concentrating on the commercialisation of its medium-duty engines. However, they could expand to offering petrol and racing engines with dimpled pistons in the future as well.

Source: MotorTrend