Abstract:
Past air intake systems have failed to effectively and efficiently utilize the arrangement of structural components to increase boost at low engine speeds. The present air intake system effectively and efficiently utilizes the arrangement of structural components to increase boost at low engine speeds. The air intake system directs intake air through a turbocharger and evaluates the quantity of flow of intake air to the engine as compared to the flow of fuel. And, depending on the results of the evaluation, a directional control valve directs the flow of intake air to a supercharger or to the engine. The supercharger is driven by a motor having a variable rate of speed as compared to the engine.

Description:
TECHNICAL FIELD 
     This invention relates generally to an engine and more particularly to an engine having a turbocharger and a supercharger. 
     BACKGROUND ART 
     Attempts have been made to provide an efficient and effective intake air supply system for engines. One such example, utilizes a turbocharger or twin turbochargers to increase the intake air supply to the engine increasing boost pressure and increasing output power. Thus, an exhaust gas from the engine which would be spent to the atmosphere is used by recovering the heat within the exhaust to drive a turbine, increasing efficiency. With the engine operating at or near high speed, an adequate supply of exhaust is available to drive the turbocharger and produce an efficient and effective air supply system for engines. However, at low speed sufficient exhaust to drive the turbocharger and produce an adequate supply of intake air is not available. Thus, the efficiency and effectiveness of the turbocharger is lost. 
     Other attempts have been made to provide and efficient and effective intake air supply for engines by incorporating a supercharger or blower. In these applications, a supercharger or blower is mechanically driven by the engine such as by a belt connected to a pulley on a crankshaft or by a gear or plurality of gears driven by the engine. With these systems, the low speed engine efficiency and effectiveness can be overcome by having a fixed speed ratio between the engine and the supercharger. For example, the speed of the supercharger can be 2 or 3 times that of the engine speed. Thus, the output of the supercharger at low engine speed can deliver adequate intake air for efficient and effective engine operation at low speed. The major disadvantage of using the supercharger is that power of the engine is used to drive the supercharger and can not be deliver as output power. 
     Attempts have also been made to combine the turbocharger system and the supercharger system. An example of one such system is disclosed in U.S. Pat. No. 4,903,488 issued to Noriyoshi Shibata on Feb. 27, 1990. The patent discloses a multiple compressed air supply system. A turbocharger is driven by an exhaust from an engine and a supercharger is drivingly connected to the engine by a belt and is driven by a crankshaft. The supercharger is driven at a constant speed relative to an engine speed. Thus, the effectiveness and efficiency of each system can be combined. However, with the system as disclosed, the efficiency and the effectiveness of the engine can be further improved. 
     The present invention is directed to overcoming one or more of the problems as set forth above. 
     SUMMARY OF THE INVENTION 
     In one aspect of the invention, an engine has a plurality of operating speeds. One of the plurality of the operating speeds being a low speed and another of the plurality of the operating speeds being a high speed. An air induction system defines a flow of intake air therein and an exhaust system defines a flow of exhaust gas therein. The air induction system is comprised of a turbocharger having a turbine section defining a turbine being driven by the flow of exhaust gas. A shaft is attached to the turbine and drives a compressor wheel. The compressor wheel compresses the flow of intake air and densifies the flow of intake air. A directional control valve has an outlet end, an inlet end being in fluid communication with the flow of intake air being compressed and densifies by the compressor wheel and a second inlet end. The directional control valve is movable between an open position and a closed position. The flow of intake air enters the inlet end with the directional control valve in the open position. And, the flow of intake air is prevented from entering the inlet end with the directional control valve in the closed position. A supercharger has an inlet end and an outlet end. The inlet end is in fluid communication with the flow of intake air. The flow of intake air is compressed and densifyed by the turbocharger prior to being communicated to the supercharger. And, the supercharger further compresses and densifies the intake air prior to exiting said outlet end. The outlet end is in fluid communication with the second inlet end of the direction control valve. And, with the directional control valve in the closed position the intake air is in fluid communication with the outlet end of the directional control valve. A motor is drivingly connected to the supercharger. The motor has a variable rate of speed and the variable rate of speed varies a quantity of flow of the intake air from the supercharger to the engine. 
     In another aspect of the invention, an engine has a plurality of operating speeds. One of the plurality of the operating speeds is a low speed and another of the plurality of the operating speeds is a high speed. An air induction system defines a flow of intake air therein and an exhaust system defines a flow of exhaust gas therein. The air induction system is comprised of a plurality of turbochargers, each having a turbine section defining a turbine being driven by the flow of exhaust gas. A shaft is attached to the turbine and drives a compressor wheel. The compressor wheel compresses the flow of intake air and densifies the flow of intake air. A plurality of directional control valves each have an outlet end, an inlet end being in fluid communication with the flow of intake air being compressed and densified by the compressor wheel. And, at least one of the plurality of directional control valves has a second inlet end. The plurality of directional control valves are movable between an open position and a closed position. The flow of intake air enters the inlet end of a respective one of the plurality of directional control valves with the plurality of directional control valves in the open position. The flow of intake air is prevented from entering the inlet end with the plurality of directional control valves in the closed position. A supercharger has an inlet end and an outlet end. The inlet end is in fluid communication with the flow of intake air. The flow of intake air is compressed and densifyed by the plurality of turbochargers prior to being communicated to the supercharger. And, the supercharger further compresses and densified the intake air prior to exiting the outlet end. The outlet end is in fluid communication with the second inlet end of the at least one of the plurality of directional control valves. With the plurality of directional control valves in the closed position, the intake air is in fluid communication with the outlet end of the plurality of directional control valves. A motor is drivingly connected to the supercharger. The motor has a variable rate of speed. The variable rate of speed varies a quantity of flow of the intake air from the supercharger. 
     In another aspect of the invention, a method of increasing a flow of intake air to an engine is disclosed. The engine defines a plurality of speeds, one of the plurality of speeds being a low speed and another of the plurality of speeds being a high speed. The engine further includes at least a turbocharger. Increasing the flow of intake air to the engine comprises the following steps. Directing the flow of intake air to a turbocharger. Compressing and densifying the flow of intake air within the turbocharger. Monitoring the flow of intake air to the engine. Monitoring a quantity of fuel to the engine. Calculating a proportional relationship of the quantity of fuel to the flow of intake air. Directing the flow of intake air from the turbocharger to at least one of a directional control valve and a supercharger. Driving the supercharger with a motor. Compressing and densified the flow of intake air further within the supercharger. And, directing the compressed and densifyed flow of intake air through the directional control valve prior to directing the increased flow of intake air to the engine. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic view of an engine embodying the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIG. 1, an engine  10  includes a block  12  having a plurality of bores  14  therein. A crankshaft  16  is rotatably positioned in the block  12  in a conventional manner and operatively moves a piston  18  within each of the plurality of bores  14 . The engine  10  includes a first air induction system  30  through which a flow of intake air, designated by arrow  32  is operatively connected to the plurality of bores  14 . And, the engine  10  includes an exhaust system  34  through which a flow of exhaust gas, designated by arrow  36  is operatively connected to the plurality of bores  14 . 
     The air induction system  30  includes an air cleaner  40  being in communication with atmospheric air. The air cleaner  40  can be of any conventional design and as an alternative could include an oil separator. The air cleaner  40  is fluidly connected with a compressor section  42  of a turbocharger  44 . In this application, a first tube  46  is interposed between the air cleaner  40  and the compressor section  42 . The compressor section  42  is fluidly connected to an aftercooler  48 . A second tube  50  is interposed between the compressor section  42  and the aftercooler  48 . The aftercooler  48  is fluidly connected to an intake manifold  52 . In this application, the aftercooler  48  is formed of a tube type configuration. But, as an alternative other configuration, such as, a primary surface or fin type configuration could be used without varying from the gist of the invention. The intake manifold  52  is attached to the engine  10  in a conventional manner and is operatively connected to the plurality of bores  14 . 
     A directional control valve  60  is positioned in the second tube  50 . The directional control valve  60  is movable between an open position  62  and a closed position  64 , shown in phantom. The directional control valve  60  is infinitely movable between the open position  62  and the closed position  64 . A first inlet end  66  of the directional control valve  60  is operatively positioned in communication with the flow of intake air  32  exiting the compressor section  42 . And, an outlet end  68  of the directional control valve  60  is operatively positioned in communication with the flow of intake air  32  going to the aftercooler  48 . The directional control valve  60  further includes a through inlet end  70 , being in communication with the outlet end  68  as will be explained later. 
     Interposed between a portion of the second tube  50  between the compressor section  42  and the directional control valve  60  is a first conduit  78  being in fluid communication with a supercharger  80 . The supercharger  80  has an inlet end  82  being connected with the first conduit  78  and an outlet end  84  being in fluid communication with the through inlet end  70  of the directional control valve  60 . The supercharger  80  is attached to a shaft  86  of a hydraulic motor  88  being operable through a variable rate of speed. As an alternative, the shaft  86  could be driven by any type of a motor such as an electric motor without changing the gist of the invention. The hydraulic motor  88  is driven in a conventional manner, not shown. Additionally, as a further alternative, the shaft  86  of the supercharger  80  can be driven mechanically such as by a belt or gear. 
     The exhaust system  34  includes an exhaust manifold  90  being in communication with the plurality of bores  14  in a conventional manner. An exhaust pipe  92  is in fluid communication with the exhaust manifold  90  and a turbine section  94  of the turbocharger  44 . A turbine  96  within the turbine section  94  is attached to a shaft  98  and drives a compressor wheel  100  of the compressor section  42  in a conventional manner. 
     Another embodiment is also shown in FIG.  1 . In this embodiment, additional elements of a like feature have been added and are designated by a “′” number. For example, a second air induction system  30 ′ has been substantially added or incorporated with the air induction system  30 . The second air induction system  30 ′ includes a second air cleaner  40 ′ being in communication with atmospheric air. The second air cleaner  40 ′ can be of any conventional design and as an alternative could include an oil separator. The second air cleaner  40 ′ is fluidly connected with a compressor section  42 ′ of a second turbocharger  44 . In this embodiment, a first tube  46 ′ is interposed between the second air cleaner  40 ′ and the compressor section  42 ′ of the second turbocharger  44 ′. The compressor section  42 ′ is fluidly connected to the aftercooler  48 . A second tube  50 ′ is interposed between the compressor section  42 ′ of the second turbocharger  44 ′ and the aftercooler  48 . The aftercooler  48  is fluidly connected to the intake manifold  52 . 
     A second directional control valve  60 ′ is positioned in the second tube  50 ′. The second directional control valve  60 ′ is movable between an open position  62 ′ and a closed position  64 ′, shown in phantom. The directional control valve  60 ′ is infinitely movable between the open position  62 ′ and the closed position  64 ′. A first inlet end  66 ′ of the second directional control valve  60 ′ is operatively positioned in communication with the flow of intake air  32  exiting the compressor section  42 ′. And, an outlet end  68 ′ of the second directional control valve  60 ′ is operatively positioned in communication with the flow of intake air  32  going to the aftercooler  48 . The second directional control valve  60 ′ further includes a through inlet end  70 ′, which in this embodiment is not used. 
     Interposed between a portion of the second tube  50 ′ between the compressor section  42 ′ and the second directional control valve  60 ′ is a first conduit  78 ′ being in fluid communication with the supercharger  80 . In this application, the first conduit  78 ′ of the second air induction system  30 ′ is connected with the first conduit  78  of the air induction system  30  and to the inlet end  82  of the supercharger  80 . The outlet end  84  of the supercharger  80  is in fluid communication with the through inlet end  70  of the directional control valve  60  of the air induction system  30 . 
     A second exhaust system  34 ′ includes the exhaust manifold  90  and an exhaust pipe  92 ′ being in fluid communication with the exhaust manifold  90  and a turbine section  94 ′ of the second turbocharger  44 ′. A turbine  96 ′ within the turbine section  94 ′ is attached to a shaft  98 ′ and drives a compressor wheel  100 ′ of the compressor section  42 ′ in a conventional manner. 
     Each of the first air induction system  30  and the second air induction system  30 ′ have a control system  110  connected thereto. In one example, the control system  110  is mechanical. For example, each of the direction control valves  60  includes a flapper  111  being rotatably positioned within a housing  112  and having a spring mechanism  113  biasing the flapper toward the closed position  64 . 
     In another embodiment the control system  110  includes a controller  114  which can be used with either or both of the first air induction system  30  and the second air induction system  30 ′. Additionally, a plurality of sensors  116  are positioned within or on the engine  10  and/or the intake air flow  32 . A portion of the plurality of sensors  116  monitor the pressure and flow rate. Another one of the plurality of sensors  116  monitors speed of the crankshaft  16 . Another one of the plurality of sensors  116  monitors the quantity of fuel being injected to the plurality of bores  14  or the engine  10 . A signal is sent from each of the sensors  116  to the controller  114 , interpreted by the controller and a signal is sent to a positioning mechanism  118 . The positioning mechanism  118  is connected to the direction control valve  60  and controls the position of the direction control valve  60  between the open position  62  and the closed position  64 . And, when the first air induction system and the second air induction system are used in combination, the positioning mechanism  118  is connected to the directional control valve  60  and the second directional control valve  60 ′. The positioning mechanism  118  controls the operative positions between the open position  62 , 62 ′ and closed position  64 , 64 ′ respectively. The positioning mechanism  118  can be of any configuration such as mechanical, electrical or hydraulic. In this application, the positioning mechanism is electrical, such as a solenoid. Additionally, the controller  114 , depending on the interpretation of the signals from the plurality of sensors varies the speed of the shaft  86  driving the supercharger  80 . Controlling the speed of the shaft  86  can be done in a variety of manners, in this application a hydroelectric server system, not shown, is used. 
     INDUSTRIAL APPLICABILITY 
     In use, the engine  10  is started in a conventional manner and is brought up to an operating speed and temperature. Fuel, from an external source, is supplied to each of the plurality of bores  14 . Intake air  32  is supplied to the engine  10 . For example, intake air  32  enters through the air cleaner  40  and passes through the first tube  46  to the compressor section  42  and is compressed by the compressor wheel  100  increasing in pressure and temperature. From the compressor section  42 , intake air  32  passes through the aftercooler  48 , is cooled becoming more dense and enters into the respective one of the plurality of bores  14 . Within the plurality of bores  14  the intake air  32  and the fuel are combusted. After combustion, the flow of exhaust gas  36  enters the exhaust manifold  90 . The flow of exhaust gas  36  passes through the exhaust pipe  92  and enters the turbine section  94  of the turbocharger  44  and drives the shaft  98  driving the compressor wheel  100 . After flowing through the turbine section  94  of the turbocharger  44 , the exhaust gas  36  exits through a muffler to the atmosphere in a conventional manner. 
     With the engine  10  operating at low speed, a need is defined to accelerate the engine to a high speed. Additional fuel is directed to the plurality of bores  14  in a conventional manner. The time required for the quantity of intake air  32  needed to efficiently and effectively accelerate the engine  10  is lacking with only the turbocharger  44  being used. For example, since the flow of exhaust  36  from the plurality of bores  14  is low or small in quantity the speed and the compressibility preformed by the turbocharger  44  is low or small resulting in a low quantity of intake air  32 . Thus, to increase the quantity of intake air  32  proportionally with the quantity of fuel the supercharger  80  is activated. 
     For example, with the control system  110  being mechanical, the spring mechanism  113  acts to bias the directional control valves  60  into the closed position  64 . As the flow of intake air  32  increases in pressure from the turbocharger  44 , 44 ′ the flapper  111  is acted on and the position of the directional control valve  60 , 60 ′ is moved toward the open position  62 , 62 ′. The greater the quantity of the pressure, the more the position of the directional control valve  60 , 60 ′ is moved toward the open position. As the pressure between the turbocharger  44 , 44 ′ and the supercharger  80  is balanced to a predetermined level, the flow of intake air  32  to the supercharger is stopped. 
     For example, with the control system  110  including the controller  114 , the directional control valve  60  is moved to the closed position  64  and the flow of intake air  32  from the turbocharger  44  passes along the first conduit  78  to the supercharger  80 . The quantity of intake air  32  passing to the aftercooler  48  is monitored and a signal is sent to the controller  114 . Depending on the signal, the speed of the shaft  86  driving the supercharger  80  is regulated. For example, if the quantity of intake air  32  is low and the quantity of fuel is high the speed of the shaft  86  is increased to a maximum. This results in increasing the quantity of intake air  32  passing through the through inlet end  70  of the directional control valve  60  and to the aftercooler  48 . As the quantity of intake air  32  increases, the speed of the shaft  86  is decreased, the position of the directional control valve  60  is moved toward the open position  62 . With the directional control valve  60  at the open position  62  little if any flow of intake air  32  is directed to the supercharger  80 . Additionally, the motor  88  can be stopped. And, the efficiency and effectiveness of the system  30  is increased. The combination accelerates the engine  10  from a slow speed to a high speed effectively, efficiently and with reduced emissions. 
     When using the combination of the first air induction system  30  and the second air induction system  30 ′, the operation is slightly different. For example, with the engine  10  operating at low speed, a need is defined to accelerate the engine to a high speed. Again, additional fuel is directed to the plurality of bores  14  in a conventional manner. The time required for the quantity of intake air  32  needed to efficiently and effectively accelerate the engine  10  is lacking with only the turbochargers  44 , 44 ′ being used. Since the flow of exhaust  36  from the plurality of bores  14  is low or small in quantity, the speed and the compressibility preformed by the turbochargers  44 , 44 ′ is low or small resulting in a low quantity of intake air  32 . Thus, to increase the quantity of intake air  32  proportionally with the quantity of fuel the supercharger  80  is activated. In this application, a single supercharger  80  is used to receive the flow of intake air  32  from each of the turbochargers  44 , 44 ′. The directional control valve  60  and the second directional control valve  60 ′ are moved to the closed position  64 , 64 ′ and the flow of intake air  32  from the turbochargers  44 , 44 ′ passes along the first conduit  78 , 78 ′ to the supercharger  80 . The quantity of intake air  32  passing to the aftercooler  48  is monitored and a signal is sent to the controller  114 . Depending on the signal, the speed of the shaft  86  driving the supercharger  80  is regulated. For example, if the quantity of intake air  32  is low and the quantity of fuel is high the speed of the shaft  86  is increased to a maximum. This results in increasing the quantity of intake air  32  passing through the through inlet end  70  of the directional control valve  60  and to the aftercooler  48 . As the quantity of intake air  32  increases, the speed of the shaft  86  is decreased. The position of the directional control valve  60  and the second directional control valve  60 ′ are moved toward the open position  62 , 62 ′. With the directional control valve  60  and the second directional valve  60 ′ at the open position  62 , 62 ′ little if any flow of intake air  32  is directed to the supercharger  80 . Additionally, the motor  88  can be stopped. And, the efficiency and effectiveness of the air induction system  30  and the second air induction system  30 ′ is increased. The combination accelerates the engine  10  from a slow speed to a high speed effectively, efficiently and with reduced emissions. 
     The efficiency and effectiveness of the first air induction system  30  and the second air induction system  30 ′ is superior to that of other systems. For example, with the turbochargers  44 , 44 ′ operating by exhaust gas  36  the energy therein is used to partially compress and densifies the intake air  32 . Thus, the intake air  32  had been partially compressed and densified by each of the turbochargers  44 , 44 ′ prior to the single supercharger  80  further compressing and densifying the intake air  32 . Furthermore, the structural arrangement of the intake air  32  flow path is simplified when using a plurality of turbochargers  44 , 44 ′ and directing the flow of intake air  32  through a singe directional valve  60 , 60 ′. 
     Other aspects objects and advantages of this invention cam be obtained from a study of the drawings, the disclosure and the appended claims.