| 摘要 |
An IC engine (1) has a cylinder block (2) with at least one cylinder (40) with a combustion chamber having at least one pair of valves arranged in the roof of the cylinder and a piston (4) reciprocable in it. The cylinder has a liner (19) arranged within the cylinder such that the top end surface (44) of the liner is substantially coincident with the upper piston ring (32) when the piston is at T.C. The cylinder has a smaller diameter upper portion and a larger diameter lower portion with an annular shoulder between and the top end surface of the cylinder liner abuts the shoulder formed on the lower end of the upper cylinder portion. The upper portion (20) of the cylinder has a minimum diameter at least equal to the inner diameter of the liner and at least one of the valve seats of corresponding valves protrudes radially of the valve seats into the wall of the upper portion of the cylinder. |
