| abstract |
In a hybrid supercharging engine comprising a turbo charger TC becoming a maximum capacity at a speed higher than a maximum torque rotating speed of an engine and a volume type supercharger SC provided in series to the TC, wherein a two step supercharging is performed while controlling the SC in such a manner as to keep a supply air amount constant without relation to an engine speed, it is possible not only to set a low BSFC but also to set twice or more BMEP of the TC supercharging engine. Further, since a supply air amount to an engine is increased by supercharging mainly by means of an SC at a time of a low speed so as to accelerate the TC, a turbo lag is prevented from generating and a performance at a time of a steady operation can be obtained even at a time of a rapid acceleration from a low speed. Still further, the SC is effectively functions even at a time of starting so as to increase a compressing pressure and a temperature of an engine so that a high ratio output engine which must be made a low compression ratio can be easily started. Accordingly, the engine can be made compact, light weight and inexpensive, and an exhaust of No x can be reduced without sacrificing a reliability of an engine. |