Fuel system for a vehicle

Abstract

A natural gas system for a vehicle includes a fuel pod, a conduit defining a flow path, a fuel control module, and an accumulator. The fuel pod includes a fuel tank configured to store natural gas. The conduit includes a first end coupled to the fuel pod and a second end configured to be coupled to an engine. The fuel control module is disposed along the flow path and configured to regulate a flow of natural gas to the engine. The accumulator is disposed along the flow path downstream of the fuel control module. The accumulator is configured to buffer variations in the flow of natural gas such that the engine receives a consistent flow of natural gas.

What is claimed is: 
     
         1 . A natural gas system for a vehicle, comprising:
 a fuel pod including a fuel tank configured to store natural gas;   a conduit defining a flow path, the conduit including a first end coupled to the fuel pod and a second end configured to be coupled to an engine;   a fuel control module disposed along the flow path and configured to regulate a flow of natural gas to the engine; and   an accumulator disposed along the flow path downstream of the fuel control module, wherein the accumulator is configured to buffer variations in the flow of natural gas such that the engine receives a consistent flow of natural gas.   
     
     
         2 . The system of  claim 1 , wherein the accumulator includes at least one of a supplementary length of conduit and a reservoir. 
     
     
         3 . The system of  claim 1 , wherein the fuel pod comprises a plurality of fuel tanks. 
     
     
         4 . The system of  claim 3 , further comprising a shutoff valve disposed along the flow path between the fuel pod and the fuel control module such that an operator may isolate the plurality of fuel tanks by closing the shutoff valve. 
     
     
         5 . The system of  claim 1 , further comprising a filter disposed along the flow path downstream of the fuel control module. 
     
     
         6 . The system of  claim 5 , further comprising a first pressure transducer positioned upstream of the filter and a second pressure transducer positioned downstream of the filter, wherein the first pressure transducer is configured to provide sensor signals relating to an upstream pressure of the natural gas and the second pressure transducer is configured to provide sensor signals relating to a downstream pressure of the natural gas. 
     
     
         7 . The system of  claim 6 , further comprising a controller configured to evaluate the sensor signals from the first pressure transducer and the second pressure transducer to determine a pressure differential across the filter. 
     
     
         8 . The system of  claim 7 , wherein the controller is configured to provide a service signal when the pressure differential across the filter exceeds a threshold value. 
     
     
         9 . A vehicle, comprising:
 an engine;   a tank configured to provide a supply flow of natural gas;   a first conduit including a first end coupled to the tank;   a valve coupled to a second end of the first conduit, wherein the first conduit comprises a high pressure flow path that extends continuously and directly from the tank to the valve, and wherein the valve is configured to provide a regulated flow of natural gas to the engine by adjusting the supply flow of natural gas;   a second conduit defining a low pressure flow path, the second conduit including a first end coupled to the valve and a second end configured to be coupled to the engine;   a pressure transducer disposed along the second conduit, wherein the pressure transducer is configured to provide sensor signals relating to a pressure of the regulated flow of natural gas;   a sensor configured to provide information relating to a requested throttle input associated with the engine; and   a controller configured to:
 monitor the sensor signals for a fluctuation in the regulated flow of natural gas; 
 evaluate a target pressure for the regulated flow of natural gas based on the fluctuation and the information from the sensor; and 
 selectively engage the valve such that the engine receives natural gas at the target pressure. 
   
     
     
         10 . The vehicle of  claim 9 , wherein the controller is configured to evaluate the sensor signals and compare the pressure of the regulated flow of natural gas to the target pressure. 
     
     
         11 . The vehicle of  claim 9 , wherein the valve includes a solenoid positioned to engage a movable valve element, wherein the pressure of the regulated flow of natural gas varies based on the position of the movable valve element. 
     
     
         12 . The vehicle of  claim 11 , wherein the valve comprises a spool valve, and wherein the movable valve element comprises a spool. 
     
     
         13 . The vehicle of  claim 9 , wherein the controller is configured to determine the target pressure based on an engine condition. 
     
     
         14 . The vehicle of  claim 9 , wherein the fluctuation comprises a pressure variation from physical interaction of the natural gas with the valve. 
     
     
         15 . A vehicle, comprising:
 a chassis including an engine coupled to a frame;   a body assembly coupled to the frame, wherein the body assembly includes a plurality of sidewalls and an upper wall; and   a natural gas fuel system, comprising:
 a fuel pod including a plurality of natural gas fuel tanks positioned along the upper wall of the body assembly, wherein the fuel pod is coupled to the engine with a conduit that defines a flow path; 
 a fuel regulator disposed along the flow path and configured to regulate a flow of natural gas to the engine; and 
 a shutoff valve disposed along the flow path between the fuel pod and the fuel regulator, 
   wherein the shutoff valve is coupled to a lower portion of the body assembly such that an operator standing alongside the vehicle may isolate the fuel pod by engaging the shutoff valve.   
     
     
         16 . The vehicle of  claim 15 , wherein the body assembly includes a fender panel, wherein the shutoff valve is positioned underneath the fender panel, and wherein the shutoff valve includes an actuation lever that protrudes through the fender panel. 
     
     
         17 . The vehicle of  claim 15 , wherein the fuel pod includes a tank wrap positioned around at least one of the plurality of natural gas fuel tanks. 
     
     
         18 . The vehicle of  claim 15 , further comprising a user access panel disposed along the flow path and coupled to the body assembly, wherein the user access panel is spaced from the fuel regulator. 
     
     
         19 . The vehicle of  claim 18 , wherein the user access panel includes a high-pressure fuel gauge, a fuel receptacle, and a manual shutoff valve. 
     
     
         20 . The vehicle of  claim 19 , wherein the fuel regulator is coupled to the frame and spaced from the plurality of sidewalls.