Induction system for supercharged engine

#This application is related to U.S. Pat. application Ser. No. 214,304, filed Dec. 8, 1980; U.S. patent application Ser. No. 214,358, filed Dec. 8, 1980; and to U.S. patent application Ser. No. 214,305, filed Dec. 8, 1980. Both applications are assigned to the assignee of this application.

#This application relates to supercharger systems and more specifically to supercharger systems which are selectively operable to deliver naturally aspirated air and supercharged air.

#During the last several years increasing cost and reduced availability of fuel has motivated many automobile manufacturers to produce more fuel efficient vehicles by not only reducing vehicle weight but by also reducing engine size or power relative to vehicle weight, thereby depriving motorists of accustomed vehicle performance, such as power for acceleration, hill-climbing, etc. To regain this performance and still retain fuel efficiency many automotive manufacturers have offered or considered offering vehicles with supercharger systems having displacement or turbodynamic blowers which are either mechanically driven by the engine crankshaft or turbine driven by the engine exhaust gases. Such systems though well-known have not met with great customer acceptance even though they had been satisfactorily used for years to maintain aircraft engine power with increasing altitude and to increase racing car speeds. Most of the automobile superchargers have been of the turbine driven-turbodynamic blower type commonly referred to as turbochargers; a few have been of the mechanically driven displacement blower type, e.g., vane or Roots blowers driven by gear arrangements, V-belts, etc.

#The supercharger system of the instant invention is shown in the accompanying drawings in which:

#FIG. 1 is a side elevational view of the supercharger system mounted on a partially shown engine;

#FIG. 2 is an end elevational view of the system looking in the direction of arrow 2 in FIG. 1; and

#Looking first at FIGS. 1-4 in general, therein is disclosed a partially shown engine 10 equipped with a carburetor 12, a supercharger 14, and an induction or supercharger system 16. The induction system includes a valve 18 (see FIGS. 3 and 4) operative in a first position of FIG. 3 to direct the flow of an air-fuel mixture from the carburetor to the engine via a first or natural aspiration path and to direct discharge air from the supercharger outlet back to the supercharger inlet via a recirculation path. Valve 18 is operative in its second position of FIG. 4 to direct the flow of an air-fuel mixture from the carburetor to the engine via a second or supercharger path.

#Carburetor 12 may be a single point fuel injector and is preferably disposed upstream of the supercharger as shown herein. However, carburetor 12 may be positioned downstream of the supercharger and may be deleted in lieu of multiple fuel injector nozzles which may inject fuel either into the manifold or directly into the expansible chambers of the engine. Further, engine 10 is preferably an Otto cycle engine of the type used in automotive and truck type vehicles. However, the engine may be of the diesel cycle type, in which case carburetor 12 would be replaced by fuel injection nozzles which inject fuel directly into the expansible chambers. Herein, engine 10 is a conventional four-cylinder, four-stroke, spark-ignited engine wherein each cylinder defines an expansible chamber having inlet and outlet ports controlled by poppet valves which are actuated by a camshaft driven by a crankshaft; none of these components are shown since they do not form a close part of the instant invention and since they are well-known. Portions of the engine, which are shown, include a valve cover 20, a head assembly 22, a block assembly 24, an air filter 26, and a crankshaft driven shaft 28 having a V-pulley 30 fixed thereto.

#Supercharger 14, which may be a turbine driven variable or positive displacement blower, is preferably a mechanically driven positive displacement blower. Herein, the supercharger is a Roots type blower having two unshown rotors with three helical lobes each. The rotors are driven by a shaft 32 having a V-pulley 34 fixed thereto and mechanically connected to V-pulley 30 via a V-belt 36. Hence, the fluid, air, or air-fuel mixture displacement of the supercharger is always in direct proportion to engine speed.