Fuel Tank System for Direct Ethanol Injection Octane Boosted Gasoline Engine

Abstract

Fuel tank system for a direct ethanol injection octane boosted gasoline engine. The system includes a gasoline engine and a main fuel tank that contains a mix of gasoline and gasoline E85. A smaller secondary tank is provided to contain ethanol or E85. An injector directly injects in a separately controlled fashion ethanol or E85 into a cylinder of the engine to boost octane. A control module controls the relative amounts of gasoline and ethanol used and structure is provided for fueling the main and secondary fuel tanks.

1 . Fuel tank system for a direct ethanol injection octane boosted gasoline engine comprising:
 a gasoline engine;   a main fuel tank that contains a mix of gasoline and E85;   a smaller secondary tank of E85;   an injector for separately controlled, direct injection of E85 from the secondary tank into a cylinder of the engine to boost octane;   a control module to control the relative amounts of gasoline and ethanol used; and   means for fueling the main and secondary fuel tanks.   
   
   
       2 . The system of  claim 1  wherein the means for fueling includes a single spigot with dual lines. 
   
   
       3 . The system of  claim 1  further including a first fuel inlet fitting accepting a nozzle that dispenses gasoline or E85, and a second fuel inlet fitting accepting a nozzle that dispenses E85. 
   
   
       4 . The system of  claim 1  wherein the smaller secondary tank is fueled by a container. 
   
   
       5 . The system of  claim 1  where in the smaller secondary tank is fueled by a pump. 
   
   
       6 . The system of  claim 4  wherein the container has a capacity of 1.0 to 2.5 gallons. 
   
   
       7 . The system of  claim 1  further including a valve allowing both tanks to be filled through use of a single inlet fitting. 
   
   
       8 . The system of  claim 1  wherein the control module reduces the amount of E85 injected into the engine when the main tank contains E85 or gasoline/E85 mixtures. 
   
   
       9 . The system of  claim 1  wherein the means of fueling refuels the main and secondary tanks simultaneously from a single dual fuel spigot having a nozzle design allowing gasoline into the main tank and ethanol into the secondary tank. 
   
   
       10 . The system of  claim 1  wherein the capacities of the main and secondary tanks can be reconfigured. 
   
   
       11 . The system of  claim 10  wherein the control module controls the reconfiguration on the basis of a previous driving pattern. 
   
   
       12 . The system of  claim 11  further including operator override of the control module to meet expected driving patterns. 
   
   
       13 . The system of  claim 1  wherein the engine in operated at a substantially stoichiometric air/fuel ratio. 
   
   
       14 . The system of  claim 1  wherein the direct injector also injects gasoline or E85 from the main tank. 
   
   
       15 . The system of  claim 1  wherein engine boost pressure, torque or horsepower is decreased to reduce consumption of E85. 
   
   
       16 . Fuel tank system for a direct ethanol injection octane boosted gasoline engine comprising:
 a gasoline engine;   a main fuel tank that contains a mix of gasoline and E85;   a smaller secondary tank of E85 an injector for direct, separately controlled, injection of E85 from the secondary tank into a cylinder of the engine to boost octane;   a control module to control the relative amounts of gasoline and ethanol used; and   means for fueling the main and secondary fuel tanks; and wherein the injector for direct injection of E85 from the secondary tank is also used to inject gasoline or E85 from the first tank and wherein the fuel/air mixture is substantially stoichiometric.