TWO-STROKE ENGINE COOLING SYSTEM

摘要

A two-stroke cycle internal combustion engine having at least one cylinder (9), an exhaust port in the peripheral wall of said cylinder (9), and a coolant passage about at least a portion of the peripheral wall of the cylinder (9). The coolant passage is arranged to commence below the level of the exhaust port and divides into two first branches (3, 4), one passing to either side of the exhaust port and communicating again at a location above the level of the exhaust port. At least one of the first branches (3, 4) is configured to extend partly about the peripheral wall of the cylinder (9) in a direction away from the exhaust port and then extend back about the peripheral wall in the opposite direction at a level above the exhaust port. Where gas inlet ports are provided in the cylinder wall, one on each side of the exhaust port, each respective first branch of the coolant passage (3, 4) is arranged to extend about the respective inlet port on the side thereof remote from the exhaust port. Alternatively, the respective first branches (3, 4) can pass between the exhaust port and the inlet port on that side of the exhaust port.