Patent ID: 7278383

Claim:
An internal combustion engine comprising: a combustion chamber; a piston; an intake valve; an exhaust valve; a variable compression ratio mechanism that changes a compression ratio by changing a capacity of the combustion chamber; a compression ratio control portion that controls the variable compression ratio mechanism so as to achieve a target compression ratio determined according to an operation state of the internal combustion engine; a variable valve characteristics mechanism that changes valve characteristics of at least one of the intake valve and the exhaust valve; a variable valve control portion that controls the variable valve characteristics mechanism so as to achieve target valve characteristics of the at least one of the intake valve and the exhaust valve that are determined according to an operation state of the internal combustion engine; and a compression ratio limit portion that determines an upper variation limit compression ratio that is an upper limit of compression ratio at which the at least one of the intake valve and the exhaust valve does not collide with the piston, according to actual valve characteristics of the at least one of the intake valve and the exhaust valve that are realized by the variable valve characteristics mechanism being controlled by the variable valve control portion, and limits the target compression ratio to the upper variation limit compression ratio when the target compression ratio is larger than the upper variation limit compression ratio.