Motor-assisted variable geometry turbocharging system

Abstract

The motor-assisted variable geometry turbocharging system has a motor to add power to the turbocharging shaft, especially at low exhaust gas volume. Additionally, the turbocharger has control over compressor air inlet direction and/or control of exhaust gas to a two-volute expander. These are individually controlled directly or indirectly from an engine controller to enhance turbocharger performance. In a preferred embodiment, the motor is an electric motor, mounted directly on the turbocharger shaft intermediate the turbo expander and turbo compressor and within the main housing.

What is claimed is: 
     
       1. A motor assisted variable geometry turbocharging system comprising; a turbo expander for being driven by engine exhaust gas;   a turbo compressor for drawing air in an inlet and delivering air under pressure to the engine, said turbo compressor and turbo expander being connected together to rotate together;   air inlet control vanes on said compressor air inlet for providing compressor inlet pre-whirl, said vanes being variable to control the amount of pre-whirl;   a vane control for controlling said vanes;   a motor connected to rotate with said compressor to supply power to said compressor to drive said compressor at low exhaust gas flow;   a motor control to control said motor, said motor control being connected to said vane control so that said motor and said vanes are both controlled by said motor controller; and   an engine control responsive to engine conditions, said engine control being connected to said motor control.   
     
     
       2. The turbocharging system of claim 1 further including an exhaust gas inlet valve connected to said exhaust gas turbine, a valve control for controlling said exhaust gas inlet valve, said valve control being controlled by said engine control and being independent of said motor control and said vane control. 
     
     
       3. The turbocharging system of claim 1 including a turbocharger shaft, said turbo expander and said turbo compressor being mounted on said shaft, said motor being an electric motor having a rotor mounted on said shaft at a location between said compressor and said expander. 
     
     
       4. The turbocharging system of claim 2 including a turbocharger shaft, said turbo expander and said turbo compressor being mounted on said shaft, said motor being an electric motor having a rotor mounted on said shaft at a location between said compressor and said expander. 
     
     
       5. A motor-assisted turbocharging system comprising: an exhaust gas turbine having an exhaust gas inlet duct for connection to receive exhaust gas from an internal combustion engine, said exhaust gas turbine having a rotating turbine wheel therein, said turbine wheel being mounted on a shaft to rotate therewith;   a turbo compressor, said shaft extending into said turbo compressor, said turbo compressor having an air inlet duct and having a wheel therein mounted to rotate with said shaft to compress air entering said air inlet duct;   a motor, said motor being connected to said shaft, said motor being energizable to rotate said shaft in an air-compressing direction, motor control means for controlling said motor;   inlet duct flow control means in at least one of said inlet ducts for controlling flow therethrough, said inlet duct flow control means including movable pre-whirl vanes in said compressor air inlet duct and a vane control connected to control positions of said movable prewhirl vanes; and   engine control means connected for controlling said inlet duct flow control means and said engine control means being also connected to said motor control means whereby said engine control means controls said turbocharging system for engine management.   
     
     
       6. The motor-assisted turbocharging system of claim 5 wherein said engine control means separately controls said inlet duct flow control means and said motor control means. 
     
     
       7. The motor-assisted turbocharging system of claim 6 wherein said exhaust gas turbine is a dual volute turbine and said inlet duct flow control means controls exhaust gas flow to one or both of said volutes. 
     
     
       8. The motor-assisted turbocharging system of claim 5 wherein said inlet duct flow control means includes a valve in said exhaust gas inlet duct to control exhaust gas flow to said exhaust gas turbine. 
     
     
       9. The motor-assisted turbocharging system of claim 8 wherein said exhaust gas turbine is a dual volute turbine and said inlet duct flow control means, when actuated, directs substantially all exhaust gas into one of said volutes to enhance turbine performance. 
     
     
       10. The motor-assisted turbocharging system of claim 9 wherein said motor is an electric motor having its rotor mounted on said shaft at a location between said compressor and said turbine wheel. 
     
     
       11. A motor-assisted turbocharging system comprising: an exhaust gas turbine having an exhaust gas inlet duct for connection to receive exhaust gas from an internal combustion engine, said exhaust gas turbine having a rotating turbine wheel therein, said turbine wheel being mounted on a shaft to rotate therewith;   a turbo compressor, said shaft extending into said turbo compressor, said turbo compressor having an air inlet duct aid having a wheel therein mounted to rotate with said shaft to compress air entering said air inlet duct;   a motor, said motor being connected to said shaft, said motor being energizable to rotate said shaft in an air-compressing direction, motor control means for controlling said motor;   air inlet duct air flow control means in said air inlet duct for controlling air flow therein; and   engine control means connected to said air inlet duct air flow control means, and said engine control means being also connected to said motor control means whereby said engine control means controls said turbocharging system to deliver adequate air for engine requirements.   
     
     
       12. The motor-assisted turbocharging system of claim 11 wherein said engine control means separately controls said inlet duct flow control means and said motor control means. 
     
     
       13. The motor-assisted turbocharging system of claim 11 wherein said engine control means includes a valve in said exhaust gas inlet duct to control exhaust gas flow to said exhaust gas turbine.