Internal combustion engine with a supercharger and an improved piston crank mechanism

A supercharged internal combustion engine is provided with a double-link type piston crank mechanism connecting between a piston and a crankshaft. The piston crank mechanism causes the piston to move at a speed which is smaller around a top dead center (TDC) and larger around a bottom dead center (BDC) as compared with respective corresponding piston speeds attained by a comparable single-link type piston crank mechanism. The double-link type piston crank mechanism variably controls a compression ratio by varying an angular position of one of links constituting the piston crank mechanism.