Operating a four-stroke spark-ignition internal combustion engine

Abstract

The use of from 0.1 to 5 wt %, based on overall gasoline composition, of a base oil having a kinematic viscosity at 100° C. of at least 1 cSt, in a gasoline composition comprising a major amount of gasoline is disclosed for improving the acceleration response of a four-stroke spark-ignition internal combustion engine fueled by the gasoline composition. A method of operating a four-stroke spark-ignition internal combustion engine is also disclosed which method involves introducing into a combustion chamber of said engine a gasoline composition comprising: (a) a major amount of a gasoline; and (b) from 0.1 wt % to 5 wt %, based on the overall gasoline composition, of a base oil having a kinematic viscosity at 100° C. of at least 1 cSt.

1 . A method of operating a four-stroke spark-ignition internal combustion engine containing a combustion chamber comprising introducing into the combustion chamber of said engine a gasoline composition comprising:
 (a) a major amount of a gasoline; and   (b) from 0.1 wt % to 5 wt %, based on the overall gasoline composition, of a base oil having a kinematic viscosity at 100° C. of at least 1 cSt.   
   
   
       2 . The method of  claim 1  wherein the amount of component (b) is from greater than 0.2 wt % to 5 wt %, based on the overall gasoline composition, of a liquid hydrocarbon base oil having a kinematic viscosity at 100° C. of at least 1 cSt. 
   
   
       3 . The method of  claim 2  wherein the amount of component (b) is in the range from 0.25 to 3.5 wt % of the overall gasoline composition. 
   
   
       4 . The method of  claim 1  wherein the kinematic viscosity at 100° C. of the base oil is in the range of from 8 to 50 cst. 
   
   
       5 . The method of  claim 1  wherein at least part of the base oil is a synthetically derived base oil.