Supercharging apparatus for use in an internal combustion engine

A supercharging apparatus for an internal combustion engine comprising:

• an intake air passage communicating with a cylinder of an engine through an intake valve;
• a mechanical supercharger provided in said intake air passage;
• variable valve timing means for varying a closing timing of said intake valve with respect to a bottom dead center of an engine piston;
• control means for controlling said variable valve timing means to change the phase of a valve lift curve of said intake valve to selectively realize first and second valve timings in accordance with the engine speed, said first valve timing having a delayed intake valve closing timing and a small valve overlap between the intake and exhaust valves compared with said second valve timing;
• assist means for causing a dynamic supercharging effect in said intake air passage when said closing timing of the intake valve is switched to said delayed timing, thereby assisting said mechanical supercharger in this specific engine operational region;
• wherein said variable valve timing means changes a phase of a valve lift curve of said intake valve so as to realize first and second valve timings, said first valve timing having a delayed intake valve closing timing and a small valve overlap between the intake and exhaust valves compared with said second valve timing;
• and
• wherein said control means controls said variable valve timing means to select said first valve timing in a low engine speed region and select said second valve timing in a high engine speed region, and said assist means causes a resonance supercharging effect in the intake air passage in said low engine speed region.