Internal combustion engines

Claim 1

IN AN AIR COOLED INTERNAL COMBUSTION ENGINE THE IMPROVEMENT COMPRISING, IN COMBINATION, A CYLINDER, A CYLINDER HEAD SURROUNDING SAID CYLINDER, AND MEANS FOR POSITIVELY DRAWING COOLED AIR THROUGH THE ENGINE AND INTO AN EXHAUST DUCT, SAID CYLINDER AND CYLINDER HEAD HAVING EXTERNAL COOLING PASSAGES DEFINED BY COOLING RIBS EXTENDING FROM THE CYLINDER AND SHROUDED BY AN ANNULUS, AND AT LEAST ONE INTERNAL COOLING CHANNEL EXTENDING THROUGH THE CYLINDER HEAD AND DEFINED IN PART BY WALLS SUBJECT TO GREAT THERMAL STRESS IN THE CYLINDER HEAD, SAID CHANNEL COMMUNICATING AT AN END THEREOF WITH ONE OF SAID COOLING PASSAGES, WHEREBY COOLING AIR DRAWN THROUGH SAID INTERNAL COOLING CHANNEL IS CONFINED THERETO AND CONTACTS SAID WALLS HAVING HIGH THERMAL STRESSES AND IS THEREAFTER CONFINED TO ONE COOLING PASSAGE ON SAID CYLINDER, WHILE THE COOLING AIR WHICH CONTACTS SAID EXTERNAL SHROUDED COOLING FINS ON SAID CYLINDER HEAD IS CONDUCTED DOWN THE REMAINDER OF SAID COOLING PASSAGES SO AS TO COOL THE CYLINDER AND THEN IS CONDUCTED TO SAID EXHAUST DUCT.