SPONTANEOUS INTAKE TYPE INTERNAL COMBUSTION ENGINE FOR VEHICLES

摘要

An internal combustion engine (E) of natural aspiration system for a vehicle operates on the Miller cycle in an operating range covering a no-load operating range and a high-load high-speed operating range at a low fuel consumption rate. The internal combustion engine E has simple, lightweight construction, is capable of being manufactured at a high productivity at a low cost. The internal combustion engine E includes a cylinder (2) provided with a cylinder bore (2a), a piston (8) fitted for reciprocation in the cylinder bore (2a), an inlet valve (35) to be opened and closed at a fixed inlet valve opening point and a fixed inlet valve closing point in the entire operating range covering a no-load operating range and a high-load high-speed operating range, and an exhaust valve (36) to be opened and closed at a fixed exhaust valve opening point and a fixed exhaust valve closing point in the entire operating range. The fixed inlet valve closing point is either a point before the bottom dead center or a point after the bottom dead center, at which intake air sucked into the cylinder (2) reverses through the inlet valve (35), and the internal combustion engine (E) has a set piston displacement which enables the internal combustion engine (E) to generate a maximum required indicated power when the inlet valve (35) is closed at the fixed inlet valve closing point in the high-load high-speed operating range.