STRUCTURE OF SHROUD OPENING FOR THE INTAKE OF COOLING AIR IN AIR-COOLING TYPE INTERNAL COMBUSTION ENGINE

摘要

In an air-cooled internal combustion engine a cylinder (14) positioned above a crank case (9) and a cylinder head (15) positioned above the cylinder are formed with a large number of radiation fins (16) arranged at predetermined intervals. A cooling fan (19) is integrally mounted on the rightmost end of a crank shaft (10). A synthetic resin shroud (20) which covers both the air-cooled type internal combustion engine (3) and the cooling fan (19) comprises a cylinder-side shroud (21) which covers both the cooling fan (19) of the engine (3) and the cylinder (14), a head-side shroud (22) which covers the cylinder head (15), and a shroud outer plate (23) which covers the outside of the cylinder-side shroud (21). In the cylinder-side shroud (21) there is formed a cylindrical opening (25), and an inner louver (26) is formed in the cylindrical opening (25). The inner louver comprises wide fins (27) which are inclined from the rear to the front in the outside direction from the inside and arranged longitudinally at wide intervals. In the shroud outer plate (23) there is formed a cylindrical opening (28) which is sideways projecting outwards, and an outer louver (29) is formed in the cylindrical opening (28). The outer louver (29) comprises relatively narrow fins (30) which are inclined from above to below in the outside direction form the inside and arranged vertically at narrow intervals.