Patent ID: 8006627

Claim:
A hydrogen hybrid locomotive including a plurality of traction motors for moving the locomotive along a set of tracks comprising: first and second hydrogen fuel cell power modules for providing electrical power to the traction motors; and a cooling system for cooling the power modules comprising: first and second radiators and corresponding first and second fans for removing heat from cooling fluid circulated through the first and second power modules; a variable speed pump for pumping the cooling fluid through the first and second power modules and the first and second radiators; a bypass valve disposed between the pump and the first and second power modules for selectively bypassing cooling fluid around the first and second radiators; an outlet valve for selectively passing cooling fluid from the first and second radiators to the first and second power modules; and a control system for selectively opening and closing the bypass and outlet valves and varying the speed of the first and second fans to control the temperature of the cooling fluid being circulated through the first and second power modules, wherein the control system is operable to selectively open and close the bypass valve as an open-loop function of a ratio of a difference between a temperature of the cooling fluid being returned to the first and second radiators from the first and second power modules and an inlet temperature setpoint of the first and second power modules and a difference between the temperature of the cooling fluid being returned to the first and second radiators from the first and second power modules and a temperature of the coolant fluid being output from the first and second radiators to the first and second power modules.