Fuel vapor reclamation system for diesel locomotives

Abstract

An on-board vapor reclamation system and method includes an air inlet into an on-board diesel fuel tank and a fuel vapor/air mixture outlet from the fuel tank. A pump or a suction fan is operable to drive air from the air inlet through the tank and a fuel vapor/air mixture out the fuel vapor/air mixture outlet at a flow rate which maintains a fuel vapor concentration in the tank to less than a predetermined value corresponding to the lower explosive limit to reduce fire and explosive hazards and to reduce harmful emissions. A condenser subsystem is fluidly connected to the fuel vapor/air mixture tank outlet and is configured to condense fuel vapor in the fuel vapor/air mixture delivered to the condenser subsystem at the required flow rate. Condensed fuel vapor from the condenser subsystem is returned to the fuel tank to save fuel and increase mileage.

1 . An on-board vapor reclamation system comprising:
 an air inlet into an on-board diesel fuel tank;   a fuel vapor/air mixture outlet from the fuel tank;   a pump operable to drive air from the air inlet through the tank and a fuel vapor/air mixture out the fuel vapor/air mixture outlet at a flow rate which maintains a fuel vapor concentration in the tank to less than a predetermined value;   a condenser subsystem fluidly connected to the fuel vapor/air mixture tank outlet and configured to condense fuel vapor in the fuel vapor/air mixture delivered to the condenser subsystem at said flow rate; and   a return line for liquid fuel from the condenser subsystem to the fuel tank.   
     
     
         2 . The system of  claim 1  in which the pump is disposed between the fuel tank fuel vapor/air mixture outlet and the condenser unit. 
     
     
         3 . The system of  claim 1  in which said pump or suction fan and condenser subsystem are disposed on or over the fuel tank. 
     
     
         4 . The system of  claim 1  further including a data acquisition module including one or more sensors. 
     
     
         5 . The system of  claim 4  in which one said sensor is a fuel vapor sensor or a thermocouple. 
     
     
         6 . The system of  claim 1  in which the condenser subsystem includes an inlet duct connected to the fuel vapor/air mixture outlet of the fuel tank, a heat exchanger, and an outlet duct connected to the fuel return line. 
     
     
         7 . The system of  claim 6  in which the inlet duct has diverging walls and the outlet duct has converging walls. 
     
     
         8 . The system of  claim 6  further including a chiller delivering a cooled fluid to the heat exchanger and receiving warmed fluid from the heat exchanger. 
     
     
         9 . The system of  claim 6  further including an outlet from the condenser to atmosphere for air in the fuel vapor/air mixture. 
     
     
         10 . The system of  claim 1  in which the predetermined value is less than 3000 ppm. 
     
     
         11 . An on-board vapor reclamation method comprising:
 urging air into an on-board locomotive diesel fuel tank and driving a fuel vapor/air mixture out of the fuel tank at a flow rate which maintains a fuel vapor concentration in the tank to less than a predetermined value;   condensing the fuel vapor in the fuel vapor/air mixture; and   returning liquid fuel to the fuel tank.   
     
     
         12 . The method of  claim 11  in which urging air into the on-board diesel fuel tank includes pumping or sucking the air/fuel vapor mixture out of the tank and providing an air inlet into the tank. 
     
     
         13 . The method of  claim 11  in which the predetermined value is less than 3000 ppm. 
     
     
         14 . A locomotive comprising:
 a diesel fuel tank;   an air inlet into the diesel fuel tank;   a fuel vapor/air mixture tank outlet;   a pump proximate the diesel fuel tank operable to drive air from the air inlet through the tank and a fuel vapor/air mixture out the fuel vapor/air mixture outlet at a flow rate which maintains the fuel vapor concentration in the tank to a less than a predetermined value;   a condenser subsystem proximate the diesel fuel tank fluidly connected to the fuel vapor/air mixture tank outlet and configured to condense the fuel vapor in the fuel vapor/air mixture delivered to the condenser at said flow rate; and   a return line for liquid fuel from the condenser subsystem to the diesel fuel tank.   
     
     
         15 . The locomotive of  claim 14  in which the pump is disposed between the fuel tank fuel vapor/air mixture outlet and the condenser unit. 
     
     
         16 . The locomotive of  claim 14  in which said pump and condenser subsystem are disposed on or over the fuel tank. 
     
     
         17 . The locomotive of  claim 14  further including a data acquisition module including one or more sensors. 
     
     
         18 . The locomotive of  claim 17  in which one said sensor is a fuel vapor sensor or a thermocouple. 
     
     
         19 . The locomotive of  claim 14  in which the condenser subsystem includes an inlet duct connected to the fuel vapor/air mixture outlet, a heat exchanger, and an outlet duct connected to the fuel return line. 
     
     
         20 . The locomotive of  claim 19  in which the inlet duct has diverging walls and the outlet duct has converging walls. 
     
     
         21 . The locomotive of  claim 19  further including a chiller delivering a cooled fluid to the heat exchanger and receiving warmed fluid from the heat exchanger. 
     
     
         22 . The locomotive of  claim 19  further including an outlet from the condenser to atmosphere for air in the vapor/air mixture. 
     
     
         23 . The locomotive of  claim 14  in which the predetermined value is less than 3000 ppm.