Gasoline fuel

Abstract

Total combustion and evaporative emissions from gasoline pump fuels can be controlled with total emissions no higher than those currently allowed by the addition of an evaporative factor such as RVP to the model predicting emissions, based on a number of considerations including the sensitivity of emission parameters (toxics, hydrocarbons, CO and NOx) as related to the variables in the predictive model (oxygenate content, sulfur, T 90 , T 50 , aromatics, olefins, benzene and RVP). The present pump gasolines will normally have compositions including T 10 no greater than 140° F., T 90 no greater than 330° F., RVP no greater than 7 psi and usually lower and sulfur no greater than 50 ppmw. Oxygenates may be eliminated, permitting T 50 values to increase which is not unfavorable from the viewpoint of total emissions provided other parameters are held within specified limits. Aromatics, olefins and benzene are normally held to maximum of 35, 10 and 1 vol % respectively to achieve satisfactorily low total emissions.

1. An unleaded gasoline pump fuel which has the following properties:
                                   T 10 , ° F.   <=140         T 50 , ° F.   >215 = <220         T 90 , ° F.   <330         RVP, psi   <=7.0         S, ppmw   <=50         Oxygen, wt %   <=3.5         Aromatics, vol %   not more than 28         Olefins, vol %   <=10         Benzene, vol %   <=1.0         Paraffins, vol. pct.   <=75         API°   >=59.                                         
 
     
     
       2. The fuel according to  claim 1  which has a RVP of 6.6 psi maximum. 
     
     
       3. The fuel according to  claim 1  which has a RVP of 6.6 to 6.9 psi. 
     
     
       4. An unleaded gasoline pump fuel which possesses the following properties:
                                   T 10 , ° F.   <=140         T 50 , ° F.   >215 = <220         T 90 , ° F.   315-330         S, ppmw   <=35         Oxygen, wt %   <=2         Aromatics, vol %   not more than 28         Olefins, vol %   <=10         Benzene, vol %   <=1.0         Paraffins, vol %   <=75         API°   >=59         RVP, psi   <=7.0.                                         
 
     
     
       5. The fuel according to  claim 1  or  4  which has an octane rating of 92 to 93 (R+M)/2 and an aromatics content of 12 to 20 vol percent and a benzene content of not more than 0.80 vol %. 
     
     
       6. The fuel according to  claim 1  or  4  which has an octane rating of 87 (R+M)/2 and an aromatics content of 12 to 20 vol percent and a benzene content of not more than 0.70 vol %. 
     
     
       7. The fuel according to  claim 1  or  4  which has a sulfur content of not more than 25 ppmw.