Abstract: A process for controlling the performance of a homogeneous charge compression (HCCI) engine in a vehicle having a hydrocarbon fuel reservoir which process is provided. The octane or cetane number of hydrocarbon fuel being supplied to the HCCI engine is adjusted by: (a) converting a portion of hydrocarbon fuel from the hydrocarbon fuel reservoir to synthesis gas; (b) converting synthesis gas produced in step (a) to a mixture of hydrocarbons having an octane number less than or a cetane number higher than that of the hydrocarbon fuel of the hydrocarbon fuel reservoir using a Fischer Tropsch process; (c) delivering (i) a portion of hydrocarbon fuel from the hydrocarbon fuel reservoir and (ii) a portion of the mixture of hydrocarbons produced in step (b) to the HCCI engine; and (d) varying the amounts of (i) and (ii) in step (c) in order to adjust the octane or cetane number of the hydrocarbon fuel being supplied to the HCCI engine. Apparatus suitable for carrying out this process is also disclosed.

Abstract: A gasoline composition is provided containing a hydrocarbon base fuel containing 5 to 20% v olefins, not greater than 5% v olefins of at least 10 carbon atoms, not greater than 5% v aromatics of at least 10 carbon atoms, initial boiling point in the range 24 to 45° C., T10 in the range 38 to 60° C., T50 in the range 77 to 110° C., T90 in the range 130 to 190° C. and final boiling point not greater than 220° C. A method of operating an automobile using such gasoline composition as fuel is provided. Use of such gasoline composition as fuel provides improved stability of engine lubricant with reduced frequency of engine oil changes.

Abstract: Use of a Fischer-Tropsch derived fuel in a fuel composition is disclosed, for the purpose of reducing catalyst degradation in a catalytically driven or catalyst containing system which is running on, or is to be run on, the composition or its products, wherein the Fischer-Tropsch derived fuel is used to reduce the level of silicon in the fuel composition, such as by reducing the concentration of silicon-containing antifoaming additive(s) in the fuel composition. It may also be used to reduce loss of efficiency of fuel atomization and/or combustion, and/or to reduce build up of silicon deposits, in a fuel consuming system which is running on, or is to be run on, the fuel composition.