Engineers behind Volvo Group’s new more fuel-efficient truck engines have received the Volvo Technology Award 2017.
Jan Eismark and colleague Michael Balthasar came up with an intelligent piston design by adding waves to the piston crown to improve the use of oxygen.
In the case of a standard piston, the injector is located at the top of the cylinder and the fuel is sprayed toward the sides of the cylinder through a number of openings in the injector. The combination of heat and pressure causes the fuel to ignite before it reaches the cylinder wall.
The flame hits the wall of the combustion chamber at a speed of up to 50 metres per second, spreads along the piston bowl wall and then collides with adjacent flames at an angle of 180 degrees, while still traveling at a high speed.
When the flames collide, they compete for the available oxygen, but the oxygen in the centre of the combustion chamber is never fully used.
“For this reason, we wanted to identify a method of leading the flames into the centre of the combustion chamber to make better use of the oxygen there,” explains Eismark.
The result of their work was the inclusion of ridges or waves in the piston crown. The piston has six ridges and the injector, which is located in the centre of the cylinder at the top of the piston, has six openings to ensure the fuel is sprayed between the ridges that lead the flames into the centre.
Extensive work has gone into ensuring the design is cost-effective, followed by thousands of hours of testing to refine the design and verify the durability of the new concept.
This innovative, intelligent solution is now in use in the latest engines from the Volvo Group and brings advantages for both customers and the environment. The more efficient combustion process it delivers has halved the quantity of soot particles emitted by the engine and has also reduced fuel consumption by an average of two percent.
”For heavy vehicles, diesel engine technology will be important for many more years to come,” says Lars Stenqvist, Volvo Group chief technology officer. “I am proud of our engineers who have once again shown that innovative solutions can still make engines more efficient for the benefit of our customers and of society as a whole.”