System and Method for Initiating Operation of a Fuel Cell Hybrid Vehicle

Abstract

The present disclosure provides a method and system for powering a hybrid electric vehicle with a fuel cell, and in particular, efficiently initiating power generation in the fuel cell, the method and system comprising electrically connecting a battery to an ultracapacitor-based propulsion energy storage; using the battery to charge the propulsion energy storage to a predetermined voltage level for powering an air delivery compressor for a predetermined amount of time; disconnecting the battery from the propulsion energy storage; electrically connecting the propulsion energy storage to the air delivery compressor; operating the air delivery compressor using the charge on the propulsion energy storage to provide a predetermined quantity of air to the fuel cell; and causing the fuel cell to generate electricity.

1 . A fuel cell hybrid electric vehicle comprising:
 a high-voltage DC bus;   an ultracapacitor-based propulsion energy storage electrically coupled to the high-voltage bus;   an air delivery compressor electrically coupled to the high-voltage bus;   a battery selectably electrically coupled to the high-voltage bus;   a fuel cell selectably electrically coupled to the high-voltage bus;   at least one electric propulsion motor selectably electrically coupled to the high-voltage bus; and,   a system controller configured to perform the steps of: electrically connecting the battery to the ultracapacitor-based propulsion energy storage, charging the ultracapacitor-based propulsion energy storage with the battery to a predetermined voltage level associated with powering an air delivery for a predetermined amount of time, disconnecting the battery from the ultracapacitor-based propulsion energy storage, electrically connecting the ultracapacitor-based propulsion energy storage to the air delivery compressor, operating the air delivery compressor using the charge on the ultracapacitor-based propulsion energy storage to provide a predetermined quantity of air to the fuel cell, and causing the fuel cell to generate electricity.   
     
     
         2 . The fuel cell hybrid electric vehicle of  claim 1 , further comprising a high voltage electrical system and a low voltage electrical system, with each electrically isolated from the other; and,
 wherein the ultracapacitor-based propulsion energy storage and the battery both form part of the high voltage electrical system.   
     
     
         3 . The fuel cell hybrid electric vehicle of  claim 1 , further comprising a first DC-to-DC converter electrically coupled between the battery and the propulsion energy storage, the first DC-to-DC converter configured to boost up voltage from the battery during the charging the ultracapacitor-based propulsion energy storage with the battery. 
     
     
         4 . The fuel cell hybrid electric vehicle of  claim 1 , further comprising a second DC-to-DC converter electrically coupled between the battery and the high-voltage DC bus, the second DC-to-DC converter configured to buck down voltage from the high-voltage DC bus during the operating the air delivery compressor using the charge on the ultracapacitor-based propulsion energy storage. 
     
     
         5 . The fuel cell hybrid electric vehicle of  claim 1 , wherein the system controller is further configured to perform the step of using the electricity generated by the fuel cell to power vehicle accessories such that air and fuel used by the fuel cell and electricity generated by the fuel cell are in approximately stoichiometric ratios. 
     
     
         6 . The fuel cell hybrid electric vehicle of  claim 5 , wherein the steps of charging the propulsion energy storage, operating the air delivery compressor, and using the electricity generated by the fuel cell are implemented using the high-voltage DC bus. 
     
     
         7 . The fuel cell hybrid electric vehicle of  claim 1 , wherein the computer executable program code is further configured to cause the system controller to determine an amount of charge on the propulsion energy storage prior to performing the step of electrically connecting the battery to the propulsion energy storage. 
     
     
         8 . The fuel cell hybrid electric vehicle of  claim 1 , wherein the battery comprises a 28 VDC battery, the air delivery compressor comprises a scroll air compressor, the predetermined voltage level is at least 75 VDC, and the predetermined amount of time is at least 5 seconds.