Complex sentence: The meaning of this is uncertain but it may indicate that it used the inertial supercharging effectthese engines ran at low temperatures, due to their patented oil-cooled piston, and spherical smallend bearing.
Split into simpler sentences: The meaning of this is uncertain but it may indicate that it used the inertial supercharging effect. These engines ran at low temperatures, due to their patented oil-cooled piston, and spherical smallend bearing.