Method and system for controlling engine performance

Abstract

Methods and systems are provided for operating a vehicle including an engine comprising a turbocharger including a compressor and a turbine. The engine further includes a bypass path configured to selectively route gas from downstream of the compressor to upstream of the turbine. In one embodiment, the method comprises selectively increasing gas flow to the engine by adjusting gas flow through the bypass path from downstream of the compressor to upstream of the turbine. In this manner, the performance of the engine may be adjusted for various operating conditions.

1 . A method of operating a vehicle comprising an engine including a bypass path and a turbocharger, the turbocharger including a compressor and a turbine, comprising,
 selectively increasing gas flow to the engine by increasing gas flow through the bypass path from downstream of the compressor to upstream of the turbine.   
     
     
         2 . The method of  claim 1 , wherein gas flow through the bypass path is increased when a notch setting is less than a threshold. 
     
     
         3 . The method of  claim 1 , wherein gas flow through the bypass path is decreased when a notch setting is greater than or equal to a speed threshold. 
     
     
         4 . The method of  claim 1 , wherein gas flow through the bypass path is increased according to a difference between a notch setting and a threshold. 
     
     
         5 . The method of  claim 1 , wherein gas flow through the bypass path is increased when a transient engine condition is detected, and wherein the vehicle is a locomotive. 
     
     
         6 . The method of  claim 1 , further comprising,
 determining an inlet temperature of the turbine; and   adjusting the bypass path according to the determined inlet temperature.   
     
     
         7 . The method of  claim 6 , wherein the bypass path is adjusted to increase flow of heated gas through the bypass path from downstream of the compressor to upstream of the turbine when the inlet temperature is less than a threshold temperature. 
     
     
         8 . The method of  claim 7 , wherein heating gas in communication with the bypass path includes routing gas through a passage in thermal contact with exhaust gasses. 
     
     
         9 . The method of  claim 6 , wherein the bypass path is adjusted to increase flow of cooled gas through the bypass path from downstream of the compressor to upstream of the turbine when the inlet temperature is greater than or equal to a threshold temperature. 
     
     
         10 . The method of  claim 1 , further comprising,
 calculating a distance of the vehicle to each of a set of predefined geographic features;   determining if the vehicle is within a threshold range of any of the predefined geographic features; and   adjusting the bypass path if the vehicle is within the threshold range of any of the predefined geographic features.   
     
     
         11 . The method of  claim 10 , wherein calculating a distance of the vehicle to each of a set of predefined geographic features includes determining geographic coordinates of the vehicle using a Global Positioning System signal. 
     
     
         12 . A method of operating a vehicle comprising an engine including a bypass path and a turbocharger including a compressor and a turbine, the bypass path configured to selectively route gas from downstream of the compressor to upstream of the turbine, comprising,
 adjusting flow through the bypass path from downstream of the compressor to upstream of the turbine based on whether the vehicle is operating in or within a threshold range of a tunnel.   
     
     
         13 . The method of  claim 12 , wherein adjusting flow through the bypass path from downstream of the compressor to upstream of the turbine includes increasing flow through the bypass path when the vehicle is within a threshold range of an entrance of the tunnel. 
     
     
         14 . The method of  claim 12 , wherein adjusting flow through the bypass path from downstream of the compressor to upstream of the turbine includes decreasing flow through the bypass path when the vehicle is in the tunnel. 
     
     
         15 . The method of  claim 12 , wherein the engine further comprises an exhaust gas recirculation system, further comprising,
 decreasing flow of gas from the exhaust gas recirculation system when the vehicle is in the tunnel.   
     
     
         16 . The method of  claim 15 , further comprising,
 increasing flow of gas from the exhaust gas recirculation system when the vehicle exits the tunnel.   
     
     
         17 . The method of  claim 12 , wherein gas from downstream of the compressor is cooled. 
     
     
         18 . A vehicle system, comprising:
 an engine including a bypass path and a turbocharger including a turbine and a compressor, the bypass path configured to selectively route gas from downstream of the compressor to upstream of the turbine; and   a control system having computer readable storage medium with code therein, the code including instructions for,   calculating a distance of the vehicle system to each of a set of predefined geographic features;   determining if the vehicle system is within a threshold range of any of the predefined geographic features; and   adjusting the bypass path if the vehicle system is within the threshold range of any of the predefined geographic features.   
     
     
         19 . The vehicle system of  claim 18 , wherein the set of predefined geographic features includes a tunnel entrance. 
     
     
         20 . The vehicle system of  claim 18 , further comprising a Global Positioning System receiver sending a signal to the control system, and wherein the code further includes instructions for,
 determining geographic coordinates of the vehicle system for calculating the distance of the vehicle system to each of the set of predefined geographic features; and   increasing flow of gas through the bypass path when the vehicle system is within the threshold range of one of the predefined geographic features.   
     
     
         21 . The vehicle system of  claim 18 , wherein the engine includes a combustion portion having at least one cylinder where a gas/fuel mixture is combusted for driving a mechanical output shaft of the engine, and wherein gas that is selectively routed through the bypass path bypasses the combustion portion of the engine. 
     
     
         22 . A method of operating a marine vehicle comprising an engine including a turbocharger including a compressor and a turbine, comprising,
 adjusting a bypass path from downstream of the compressor to upstream of the turbine when an engine acceleration exceeds an acceleration threshold; and   adjusting the bypass path from downstream of the compressor to upstream of the turbine when an engine deceleration exceeds a deceleration threshold.   
     
     
         23 . The method of  claim 22 , wherein the bypass path is adjusted according to an engine speed and a propeller load when the engine acceleration exceeds the acceleration threshold. 
     
     
         24 . The method of  claim 23 , wherein gas flow through the bypass path is heated when the engine acceleration exceeds the acceleration threshold. 
     
     
         25 . The method of  claim 22 , wherein the bypass path is adjusted according to an intake manifold pressure, an engine speed, and a propeller load when the engine deceleration exceeds the deceleration threshold. 
     
     
         26 . The method of  claim 22 , wherein the deceleration threshold and the acceleration threshold vary according to engine speed. 
     
     
         27 . A marine vehicle system, comprising:
 an engine including a bypass path and a turbocharger including a turbine and a compressor, the bypass path configured to selectively route gas from downstream of the compressor to upstream of the turbine;   a propeller;   a coupling device connected to the engine and configured to selectively engage and disengage with the propeller;   a control system having computer readable storage medium with code therein, the code including instructions for,   selectively engaging the propeller;   selectively disengaging the propeller;   adjusting a bypass path from downstream of the compressor to upstream of the turbine when an engine acceleration exceeds an acceleration threshold and the propeller is engaged; and   adjusting the bypass path from downstream of the compressor to upstream of the turbine when an engine deceleration exceeds a deceleration threshold.   
     
     
         28 . The marine vehicle system of  claim 27 , wherein the bypass path is adjusted according to an engine speed when the engine acceleration exceeds the acceleration threshold and the propeller is engaged. 
     
     
         29 . The marine vehicle system of  claim 27 , wherein gas flow through the bypass path is heated when the engine acceleration exceeds the acceleration threshold and the propeller is engaged. 
     
     
         30 . The marine vehicle system of  claim 27 , wherein the bypass path is adjusted according to an intake manifold pressure and an engine speed when the engine deceleration exceeds the deceleration threshold.