Schneurle porting means the engine has multiple ports in the cylinder allowing fuel into the combustion chamber. Non schnuerle ported engines or 'loop scavenged' engines have only one port opposite the exhaust port which may allow fuel to pass over the piston and exit out through the exhaust port. The multiple ports of schnuerle engines causes fuel to flow from different directions to converge at the centre of the cylinder allowing more fuel to be burned and therefore more power. Most modern engines use schnuerle porting.
