System for selective homogeneous charge compression ignition

Abstract

A method of operating an internal combustion engine may include selectively operating the engine in a first mode of operation, wherein fuel may be injected into compressed fluid to create a substantially heterogeneous mixture of fuel and compressed fluid, and fuel may be ignited by the heat of the compressed fluid. The method may also include selectively operating the engine in a second mode of operation, wherein fuel is injected into gas to create a substantially homogeneous mixture of gas and fuel, the substantially homogeneous mixture is compressed, and fuel is ignited by the heat of the compressed gas. The method may further include determining whether to operate the engine in the first or second mode according to engine conditions.

1 . A method of operating an internal combustion engine, comprising: 
 selectively operating the engine in a first mode of operation, wherein fuel is injected into compressed fluid to create a substantially heterogeneous mixture of fuel and compressed fluid, and fuel is ignited by the heat of the compressed fluid;    selectively operating the engine in a second mode of operation, wherein fuel is injected into gas to create a substantially homogeneous mixture of gas and fuel, the substantially homogeneous mixture is compressed, and fuel is ignited by the heat of the compressed gas; and    determining whether to operate the engine in the first or second mode according to engine conditions.    
   
   
       2 . The method of  claim 1 , further including providing the engine with at least one piston, wherein fuel is injected closer to a top dead center position of the piston in the first mode than in the second mode.  
   
   
       3 . The method of  claim 1 , further including decreasing the volume of gas in the second mode to delay the ignition of fuel.  
   
   
       4 . The method of  claim 1 , further including providing the engine with an SCR catalyst, wherein the engine is operated in the second mode when the temperature of the SCR catalyst is below a threshold level.  
   
   
       5 . The method of  claim 4 , wherein the threshold level is approximately 200° C.  
   
   
       6 . The method of  claim 1 , wherein the fluid is a mixture of gas and fuel.  
   
   
       7 . The method of  claim 1 , further including operating the engine in the second mode when the engine is at idle.  
   
   
       8 . The method of  claim 1 , wherein in the second mode of operation, a plurality of fuel injections occur prior to ignition.  
   
   
       9 . An internal combustion engine, comprising: 
 a combustion chamber including a piston and a cylinder; and    a fuel injection controller that selectively operates the engine in first and second modes of operation, and selects the mode according to engine conditions;    wherein in the first mode, fuel is injected into compressed fluid to create a substantially heterogeneous mixture of fuel and compressed fluid, and fuel is ignited by the heat of the compressed fluid; and    wherein in the second mode, fuel is injected into gas to create a substantially homogeneous mixture of gas and fuel, the substantially homogeneous mixture is compressed, and fuel is ignited by the heat of the compressed gas.    
   
   
       10 . The engine of  claim 9 , wherein fuel is injected closer to a top dead center position of the piston in the first mode than in the second mode.  
   
   
       11 . The engine of  claim 9 , wherein the fuel injection controller operates the engine in the second mode when the engine is at idle.  
   
   
       12 . The engine of  claim 9 , further including an SCR catalyst, wherein the engine is operated in the second mode when the temperature of the SCR catalyst is below a threshold level.  
   
   
       13 . The engine of  claim 12 , wherein the threshold level is approximately 200° C.  
   
   
       14 . The engine of  claim 9 , wherein the fluid is a mixture of gas and fuel.  
   
   
       15 . A work machine having an internal combustion engine, comprising: 
 a combustion chamber including a piston and a cylinder; and    a fuel injection controller that selectively operates the engine in first and second modes of operation, and selects the mode according to engine conditions;    wherein in the first mode, fuel is injected into compressed fluid to create a substantially heterogeneous mixture of fuel and compressed fluid, and fuel is ignited by the heat of the compressed fluid; and    wherein in the second mode, fuel is injected into gas to create a substantially homogeneous mixture of gas and fuel, the substantially homogeneous mixture is compressed, and fuel is ignited by the heat of the compressed gas.    
   
   
       16 . The work machine of  claim 15 , wherein fuel is injected closer to a top dead center position of the piston in the first mode than in the second mode.  
   
   
       17 . The work machine of  claim 15 , wherein the fuel injection controller operates the engine in the second mode when the engine is at idle.  
   
   
       18 . The work machine of  claim 15 , further including an SCR catalyst, wherein the engine is operated in the second mode when the temperature of the SCR catalyst is below a threshold level.  
   
   
       19 . The work machine of  claim 17 , wherein the threshold level is approximately 200° C.  
   
   
       20 . The work machine of  claim 15 , wherein the fluid is a mixture of gas and fuel.