Portable 4-cycle engine and portable machine equipped with the 4-cycle engine

A portable 4-cycle engine allowing cooling air to flow in a direction of a crankshaft, comprising:

• a cylinder;
• a cylinder head disposed on said cylinder, and including a combustion chamber at a side of said cylinder;
• an intake port and an exhaust port, said intake port and said exhaust port being oppositely formed with each other in said cylinder head in a direction orthogonal to said crankshaft;
• a cooling fan for introducing the cooling air to said cylinder head, said cooling fan being connected to an end of the crankshaft;
• a valve train area formed above said intake port and said exhaust port, said valve train area being connected to said intake port and said exhaust port with a pair of valve guide bosses;
• and
• a plurality of vertical fins protruding upwardly from said cylinder head and extending in the direction of said crankshaft,
• wherein:
• said valve train area and said plurality of vertical fins are integrally formed with said cylinder head;
• said cylinder head, said intake port, said exhaust port, said valve guide bosses and a bottom of said valve train area together form an opening, through which the cooling air flows;
• a push rod guide having bores for accommodating a pair of push rods is formed in said valve train area at the downwind side of said cooling air;
• said bottom of said valve train area inclines downwardly from the upwind side of said cooling air toward the side of said push rod guide;
• and
• the upwind side of said valve train area is connected to said intake port and said exhaust port with said vertical fins.

A portable 4-cycle engine allowing cooling air to flow in a direction of a crankshaft, comprising:

• a cylinder;
• a cylinder head disposed on said cylinder, and including a combustion chamber at a side of said cylinder;
• an intake port and an exhaust port, said intake port and said exhaust port being oppositely formed with each other in said cylinder head in a direction orthogonal to said crankshaft;
• a cooling fan for introducing the cooling air to said cylinder head, said cooling fan being connected to an end of the crankshaft;
• a valve train area formed above said intake port and said exhaust port, said valve train area being connected to said intake port and said exhaust port with a pair of valve guide bosses;
• and
• a plurality of vertical fins protruding upwardly from said cylinder head and extending in the direction of said crankshaft,
• wherein:
• said cylinder head, said intake port, said exhaust port, said valve guide bosses and a bottom of said valve train area together form an opening, through which the cooling air flows;
• said valve train area and said plurality of vertical fins are integrally formed with each other and are also integrally formed with said cylinder head;
• said vertical fins are located at positions a predetermined distance away from respective centers of said valve guide bosses;
• and
• one of said vertical fins connected with an outer periphery of said exhaust port extends from said opening to said cooling fan side, and an ignition plug is located near the vertical fin and said opening so as to effectively introduce the cooling air to the outer periphery of said exhaust port.