Volvo’s truck engines are now much more efficient thanks to a new piston head design. The design adds “waves” to the piston’s crown, improving oxygen use. The engineers who designed the piston head have received Volvo’s Technology Award 2017 for their work.
The new wave piston design works by better distributing the oxygen and fuel in the cylinder during compression and combustion. In a standard piston design, injectors are located at the cop of the cylinder with fuel being sprayed towards the sides of the cylinder. When the fuel ignites from pressure and heat in a diesel engine design, the flame hits the combustion chamber walls at up to 50 meters per second. As it spreads along the piston bowl wall, the flames collide with adjacent flames at a 180-degree angle.
Colliding flames must compete for available oxygen and because of the flames’ positioning along the cylinder walls, the oxygen at the center of the cylinder is often under-utilized.
By adding “waves” to the cylinder head, the Volvo engineers were able to better mix the flames as they spread, utilizing more of that center-piston oxygen. This results in a better burn, higher efficiency, and more power output for the same amount of air and fuel.