Ashless consumable engine oil

Abstract

The present invention relates to a low sulfur, low phosphorus, low-ash, zinc free consumable lubricant composition suitable for use in an internal combustion engine, comprising: an oil of lubricating viscosity containing less than 0.01 percent by weight of sulfur; a high TBN succinimide dispersant and overall all lubricant composition that has a sulfated ash value of up to about 0.2, a phosphorus content of up to about 50 to about 800 ppm and a sulfur content of up to about 0.4 percent by weight.

1 . A low-sulfur, low-phosphorus, low-ash consumable composition suitable for use in an internal combustion engine, comprising: 
 (a) an oil of lubricating viscosity, and    (b) a succinimide dispersant with a TBN of at least 80 on a diluent-free basis, in an amount sufficient to provide at least 8 TBN to the combination of (a) and (b);    wherein said combination of (a) and (b) has a zinc content of 0 to about 0.05 percent by weight and has a percent sulfated ash value of up to about 0.2, a phosphorus content of about 50 to about 800 ppm and a sulfur content of up to about 0.4 percent by weight;    further comprising (c) a diesel fuel having a sulfur content of 0 to about 50 ppm.    
   
   
       2 . The composition of  claim 1 , wherein said succinimide dispersant is the product of polyisobutylene succinic anhydride, wherein the polyisobutylene group has a number average molecular weight of about 500 to about 2000, condensed with polyethylene amine having about 4 to about 6 nitrogen atoms.  
   
   
       3 . The composition of  claim 2 , wherein said dispersant has a nitrogen: carbonyl ratio of at least 1.6.  
   
   
       4 . The composition of  claim 2 , wherein the amount of said succinimide dispersant is about 1 to 15 percent by weight of the combination of (a) and (b).  
   
   
       5 . The composition of  claim 1 , further comprising at least one antioxidant.  
   
   
       6 . The composition of  claim 1 , further comprising an anti-wear agent.  
   
   
       7 . The composition of  claim 6 , wherein the anti-wear agent is phosphate or phosphite.  
   
   
       8 . The composition of  claim 1 , further comprising a corrosion inhibitor.  
   
   
       9 . The composition of  claim 1 , further comprising a pour point depressant.  
   
   
       10 . The composition of  claim 9 , wherein the pour point depressant is an esterified polymer of maleic anhydride and styrene.  
   
   
       11 . The composition of  claim 1 , further comprising a foam inhibitor.  
   
   
       12 . The composition of  claim 1 , wherein the oil of lubricating viscosity contains less than 0.01 percent by weight of sulfur.  
   
   
       13 . A method of operating an internal combustion engine, comprising: 
 (i) supplying to said engine a lubricant comprising (a) an oil of lubricating viscosity and (b) a succinimide dispersant with a TBN of at least 80 on a diluent-free basis, in an amount sufficient to provide at least 8 TBN to the lubricant;    wherein said lubricant has a zinc content of 0 to about 0.05 percent by weight and has a percent sulfated ash value of up to about 0.2, a phosphorus content of about 50 to about 800 ppm and a sulfur content of up to about 0.4 percent by weight;    (ii) removing a portion of the lubricant of (i);    (iii) combining the removed portion of (ii) with a major amount of a diesel fuel having a sulfur content of 0 to about 50 ppm;    (iv) feeding the combined portion of (iii) into the combustion chamber of said engine, where said combined portion is consumed.    
   
   
       14 . The method of  claim 13 , wherein a portion of the lubricant is consumed during operation of said engine and an additional amount is added to said engine to replace said consumed lubricant.  
   
   
       15 . The method of  claim 13 , wherein the internal combustion engine is equipped with exhaust gas recirculation.  
   
   
       16 . The method of  claim 13 , wherein the internal combustion engine is a heavy duty diesel engine.  
   
   
       17 . The method of  claim 16 , wherein the heavy duty diesel further comprises an exhaust after treatment device.