Optimized Fuel Management System for Direct Injection Ethanol Enhancement of Gasoline Engines

Abstract

Fuel management system for enhanced operation of a spark ignition gasoline engine. Injectors inject an anti-knock agent such as ethanol directly into a cylinder. It is preferred that the direct injection occur after the inlet valve is closed. It is also preferred that stoichiometric operation with a three way catalyst be used to minimize emissions. In addition, it is also preferred that the anti-knock agents have a heat of vaporization per unit of combustion energy that is at least three times that of gasoline.

1 - 25 . (canceled) 
   
   
       26 . A turbocharged or supercharged direct injection spark ignition engine which is fueled with gasoline and ethanol;
 and where ethanol is directly injected in such a way that the vaporization cooling enhances the octane number of the fuel by more than the effect of the intrinsic octane of ethanol;   and where the engine is operated at different ethanol/gasoline ratios;   and where the combination of the vaporization cooling and the intrinsic octane number of ethanol increases the octane number of the fuel at a rate of at least four octane numbers relative to the intrinsic octane number of the gasoline for every twenty percent of the total fuel energy that is provided by the ethanol.   
   
   
       27 . The turbocharged or supercharged direct injection spark ignition engine of  claim 26  where the octane number is enhanced by 35 octane numbers relative to the intrinsic octane number of gasoline. 
   
   
       28 . The turbocharged or supercharged direct injection spark ignition engine of  claim 26  where the engine is operated without knock at more than twice the manifold pressure than the knock free manifold pressure if the octane number of the fuel in the engine was the intrinsic octane of gasoline alone. 
   
   
       29 . The turbocharged or supercharged direct injection spark ignition engine of  claim 26  where the compression ratio of the engine is 11 or greater. 
   
   
       30 . The turbocharged or supercharged direct injection spark ignition engine of  claim 26  where the engine is operated without ethanol. 
   
   
       31 . The turbocharged or supercharged direct injection spark ignition engine of  claim 26  where the spark retard is changed when the ethanol/gasoline ratio is changed. 
   
   
       32 . The turbocharged or supercharged direct injection spark ignition engine of  claim 26  where the maximum level of turbocharging is reduced when the ethanol/gasoline ratio is decreased when the ethanol/gasoline ratio is reduced. 
   
   
       33 . The turbocharged or supercharged direct injection spark ignition engine of  claim 28  where water is also directly injected into the engine through the same injector as the ethanol is injected. 
   
   
       34 . The turbocharged or supercharged direct injection spark ignition engine of  claim 30  where the water content is five percent or more of the ethanol content. 
   
   
       35 . The turbocharged or supercharged direct injection engine of  claim 26  where gasoline and ethanol are directly injected into the engine through the same injector. 
   
   
       36 . A turbocharged or supercharged direct injection spark ignition engine which is fueled with gasoline and with a second fuel and where the second fuel is directly injected into the engine;
 and where the engine is operated with different second fuel/gasoline ratios;   and where the spark retard is changed when the second/gasoline ratio is changed.   
   
   
       37 . The turbocharged or supercharged direct injection spark ignition engine where the second fuel is ethanol. 
   
   
       38 . The turbocharged or supercharged direct injection spark ignition engine of  claim 36  where the second fuel is methanol. 
   
   
       39 . The turbocharged or supercharged direct injection spark ignition engine of  claim 36  where the maximum level of turbocharging is changed when the second fuel/gasoline ratio is changed. 
   
   
       40 . The turbocharged or supercharged direct injection spark ignition engine of  claim 39  where water is directly injected into the engine through the same injector that injects second fuel and gasoline. 
   
   
       41 . A turbocharged or supercharged direct injection spark ignition engine where a liquid fuel is directly injected so as to provide a non-uniform distribution of the fuel in the cylinder with a higher concentration in the end gas regions that are prone to knock. 
   
   
       42 . The turbocharged or supercharged direct injection spark ignition engine of  claim 41  where the liquid fuel is directly injected so as produce a non-uniform distribution of the fuel with a higher concentration near the walls of the cylinders. 
   
   
       43 . The turbocharged or supercharged direct injection spark ignition engine of  claim 42  further including the use of swirl. 
   
   
       44 . The turbocharged or supercharged direct injection spark ignition engine of  claim 42  where fuel is introduced into the engine by an additional injector which is separate from the injector that provides the non-uniform distribution of the fuel. 
   
   
       45 . The turbocharged or supercharged direct injection spark ignition engine of  claim 44  where the additional injector is a port fuel injector. 
   
   
       46 . The turbocharged or supercharged direct injection spark ignition engine of  claim 42  where the engine is fueled with a mixture of ethanol and gasoline and where the ethanol energy fraction needed for knock suppression is reduced by the non-uniform injection. 
   
   
       47 . The turbocharged or supercharged direct injection spark ignition engine of  claim 46  where water is also directly injected into the engine. 
   
   
       48 . The turbocharged or supercharged direct injection spark ignition engine of  claim 46  where ethanol and water are directly injected into the engine. 
   
   
       49 . The turbocharged or supercharged direct injection spark ignition engine of  claim 48  where the water content is five percent or greater of the ethanol content. 
   
   
       50 . A turbocharged or supercharged direct injection spark ignition engine where a first fuel is introduced into the manifold of a spark ignition engine and where a second fuel which is a liquid is directly injected into the engine;
 and where the engine is operated part of the time with the first fuel alone.   
   
   
       51 . The turbocharged or supercharged direct injection spark ignition engine of  claim 51  where the ratio of second fuel to the first fuel is varied so as to prevent knock as the torque is increased. 
   
   
       52 . The turbocharged or supercharged direct injection spark ignition engine of  claim 51  where the engine is operated only on the first fuel during cold start. 
   
   
       53 . The turbocharged or supercharged direct injection spark ignition engine of  claim 50  where the engine is operated on a higher fraction of the first fuel during cold start. 
   
   
       54 . The turbocharged or supercharged direct injection spark ignition engine of  claim 50  where the second fuel is ethanol.