Improving the performance of motor gasolines by optimizing their knock resistance distribution factor

The growth of gasoline consumption worldwide is imposing stricter operational and environmental requirements on fuel quality. These requirements include not only a high knock resistance of gasoline, but also a uniform distribution of the octane number by fractions. The latter property is of great importance for reliable operation of the engine at variable modes. At the same time, most of the currently used oxygenates and additives produced on their basis exhibit a narrow boiling point range and are unevenly distributed over the fuel fractions. In this work, we study industrially available oxygenates, including methyl-tert-butyl ether, isobutyl alcohol, and a mixture of saturated hydrocarbons obtained in the process of sulfuric acid alkylation of olefins (alkylate). A composite mixture of alkylate, methyl tert-butyl ether, and isobutyl in the ratio of 50-70 wt%, 15-25 wt%, and 15-25 wt%, respectively, is proposed. This composition allows an equal increase in the octane number of narrow low-boiling and high-boiling fractions in the gasoline mixture, with the factor of knock resistance distribution being close to the maximum value of 1. The effect of the studied three-component mixture on the performance of respective motor gasolines was investigated. It was found that the addition of the studied mixture as a high-octane oxygencontaining fuel component in the concentration range from 25.0 to 45.5 wt% provides for a uniform distribution of knock resistance over the fractions and improves the energy efficiency of the fuel by increasing its specific heat of combustion.

distribution coefficient of detonation resistance, energy efficiency, oxygenates, light hydrocarbons, motor gasolines