Engine

An engine comprising:

• a cylinder head defining a head accommodation space;
• an intake and exhaust system at least partially located in the head accommodation space, the intake and exhaust system comprising at least one intake valve and at least one exhaust valve;
• a cam assembly accommodated in the head accommodation space for controlling timing of reciprocation of the at least one intake valve and of the at least one exhaust valve;
• wherein the cam assembly comprises:
• at least one camshaft at least partially accommodated in the head accommodation space;
• and
• a shaft seat at least partially accommodated in the head accommodation space for supporting and containing the camshaft, wherein the shaft seat comprises:
• a lubricant hole penetrating through the shaft seat and in fluid communication with the camshaft;
• and
• a sump structure arranged around the lubricant hole, thereby effectively allowing splashed lubricant to be collected in the sump structure and deposited onto the camshaft through the lubricant hole;
• a crankcase defining a crankcase accommodation space;
• a crankshaft and connecting rod assembly at least partially accommodated in the crankcase accommodation space;
• and
• a cylinder block defining at least one cylinder hole, with a piston reciprocating in the cylinder hole along a cylinder axis, the cylinder block and the cylinder head being connected with a combustion space in the cylinder hole between the piston and the cylinder head, the piston driving the crankshaft and connecting rod assembly to rotate.

An engine comprising:

• a cylinder head defining a head accommodation space;
• an intake and exhaust system at least partially located in the head accommodation space, the intake and exhaust system comprising at least one intake valve and at least one exhaust valve;
• a cam assembly accommodated in the head accommodation space for controlling timing of reciprocation of the at least one intake valve and of the at least one exhaust valve;
• a crankcase defining a crankcase accommodation space;
• a crankshaft and connecting rod assembly at least partially accommodated in the crankcase accommodation space;
• a cylinder block defining at least one cylinder hole, with a piston reciprocating in the cylinder hole along a cylinder axis, the cylinder block and the cylinder head being connected with a combustion space in the cylinder hole between the piston and the cylinder head, the piston driving the crankshaft and connecting rod assembly to rotate;
• a cylinder head cover connected to the cylinder head and sealing the head accommodation space, the cylinder head cover defining a spark plug hole and a ventilation hole in fluid communication with the spark plug hole, and
• a sparking mechanism received in the spark plug hole, the sparking mechanism comprising a spark plug and an ignition coil, with the ventilation hole connecting to the spark plug hole beneath at least a portion of the ignition coil.