At present if an engineer was designing a four-cycle diesel
engine with large 'breathing' requirements, it probably meant they
would need to use a four valve head. However, there is more complexity
with fitting four ports and the required parts and runners into the
head. Also with four valves in the cylinder it is unavoidable that the
ports are shrouded by the cylinder walls. Also the flow out of the two
intake ports has a tendency to interfere with each other's flow.
In the Uniport Valve, the intake and the exhaust port are one in the
same. The one port can be made bigger than when there are ports
competing for space. With the bigger port, it is easier for air to
leave and enter the cylinder reducing pumping loses and increasing
volumetric efficiency. Also, the port can now be put in the center of
the cylinder. This should help with the flow of the incoming air since
the cylinder walls are now further away. These and other factors should
help improve the over all efficiency of an engine.