| 摘要 |
An internal combustion engine including variable compression ratio, comprises a crankcase and a crankshaft including a crankshaft axis, wherein the crankshaft has at least a central main portion, a crankpin and a crankshaft web located between the central main portion and the crankpin. The crankshaft is supported by the crankcase and rotatable with respect thereto about the crankshaft axis. The engine also comprises a crank member being rotatably mounted on the crankpin, and comprising at least a bearing portion which is eccentrically disposed with respect to the crankpin. The crank member has an external crank member gear which meshes with an external drive shaft gear which is fixed to a drive shaft that extends through the crankshaft web and has a driven portion which is located at a side of the crankshaft web which is opposite to its side where the crankpin is located. The driven portion is drivably coupled via a first transmission to an intermediate member which is rotatably mounted to the crankshaft and rotatable with respect to the crankshaft about an intermediate member axis extending parallel to the crankshaft axis. The intermediate member is also drivably coupled to a control shaft portion of a control shaft via a second transmission which control shaft portion is located at axial distance of the driven portion of the drive shaft and the control shaft is rotatable with respect to the crankcase about the crankshaft axis, but which has a fixed rotational position with respect to the crankcase under operating conditions at fixed compression ratio. The first and second transmissions are configured such and the dimensions of the crank member gear and the drive shaft gear are selected such that under said operating conditions the crank member rotates at a rotation frequency with respect to the crankcase which is half of that of the crankshaft and in the same rotational direction as the crankshaft as seen from the crankcase. |
