the charge flowing upward essentially along cylinder wall adjacent the inlet ports, e.g. by means of deflection rib on piston

Full Title

Engines characterised by using fresh charge for scavenging cylinders > using reverse-flow scavenging, e.g. with both outlet and inlet ports arranged near bottom of piston stroke > the charge flowing upward essentially along cylinder wall adjacent the inlet ports, e.g. by means of deflection rib on piston