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Six commercial different additive packages to be used in the Venezuelan Internal Market Diesel formulations were evaluated in terms of their performance in corrosion inhibition, oxidation stability, injector cleanliness and emissions, as well as fuel economy improvement. Laboratory, field and bench tests were carried out. In laboratory tests, additives evaluated were added to four Venezuelan Diesel fuel formulations at the recommended supplier doses: corrosion (ASTM D665), oxidation stability (ASTM D2274), emulsification (ASTM D1094). Also, physicochemical properties required by Venezuelan Diesel fuel specifications were evaluated. Three different trucks (per additive) were run in fleet tests in order to determine injector cleanliness performance. Truck injector flow was measured in every injector, according to ISO 4010 procedure, before and after 5000-6000 km field accumulations. Two trucks were run without additive dosification, and were used for base line comparison.

In order to evaluate the deposit-forming tendency produced by polar compounds in gasoline, acidic and basic compounds were isolated from four 190°C+ fractions of cracked Venezuelan components. These compounds were isolated from each component by aqueous sodium hydroxide and hydrochloric acid extractions, respectively. The remaining organic layer was then passed through a silica gel chromatography column on which the polar compounds were retained; the non-polar compounds were eluted directly. In order to elute the polar compounds from the silica column, four solvents were used (hexane, toluene, ethyl acetate and methanol). Each solvent fraction was characterized by IR, NMR-1H and -13C, and FIA, sulfur, and total nitrogen were determined. Tests were performed with an ISD apparatus to evaluate deposit forming tendency of the different fractions. The non-polar material eluted directly from the column showed decreases (67-100%) in ISD deposits in comparison to the initial 190+°C fractions.

In order to evaluate the deposit forming tendency produced by gasoline cracked components in vehicle intake systems, four cracked components of Venezuelan gasolines were separated into fractions by distillation ranges: IBP-55 °C, 55-110 °C, 110-150 °C, 150-190 °C and 190+ °C. A fifth low-boiling range cracked component was separated into fractions with the following distillation ranges: IBP-55 °C, 55-110 °C and 110+ °C. Sulfur, total and basic nitrogen and gum content, as well as the saturates, olefinic and aromatic contents were determined for each fraction. The fractions were also tested in an Induction System Deposit (ISD) apparatus for their deposit-forming tendency. Aromatic, sulfur, total and basic nitrogen and gum content increased with fraction distillation range for each component. Each of the total components evaluated showed a small tendency to form deposit by the ISD apparatus test method (<1.3 mg/100 ml).