Present Day Engins Pollutant Emissions: Proposed Model for Refinery Bases Impact (2003)

Air quality improvement, especially in urban areas, is one of the major concerns for the coming years. For this reason, car manufacturers, equipment manufacturers and refiners have explored development issues to comply with increasingly severe anti-pollution requirements. In such a context, the identification of the most promising improvement options is essential. A research program, carried out by IFP (Institut français du pétrole), and supported by the French Ministry of Industry, PSA-Peugeot-Citroën, Renault and RVI (Renault Véhicules Industriels), has been built to study this point. It is based on a four years program with different steps focused on new engine technologies which will be available in the next 20 years in order to answer to more and more severe pollutant and CO2 emissions regulations. This program is divided into three main parts: the first one for Diesel car engines, the second for Diesel truck engines and the third for spark ignition engines. The aim of the work reported here is to characterize the effect of fuel formulation on pollutant emissions and engine tuning for different engine technologies. The originality of this study is to use refinery bases as parameters and not conventional physical or chemical parameters. The tested fuels have been chosen in order to represent the major refinery bases expected to be produced in the near future. These results, expressed with linear correlations between fuel composition and pollutant emissions, will help to give a new orientation to refinery tool. The engines presented in this publication are, for spark ignition engines an EuroII lean-burn engine (Honda VTEC which equips the Honda Civic) and an EuroIII 1. 8 l stoichiometric-running Renault engine which equips the Laguna vehicles and, for diesel engines an EuroII Renault Laguna 2. 2 l indirect injection diesel engine and an EuroII RVI truck engine. For the fuel formulation, an original approach is proposed: while the classical studies are based on the properties of the fuel, this one is built only on a refinery bases approach. For diesel fuels, six refinery bases (a straight-run diesel fuel, an hydro-cracked diesel fuel, a LCO, a diesel fuel obtained by hydro-conversion of vacuum distillation residue, a kerosene and a diesel fuel issued from a Fischer-Tropsch process) have been selected to produce a fuel matrix which was determined according to an experimental blend design. For gasoline fuels, seven bases have been chosen, which are representative of the batch that will be used in the next years: a fuel from isomeration process (mainly constituted of C5/C6 isoparafins), an alkylate (constituted of C7+ isoparafins), a fuel from olefins oligomerization process, a fuel from catalytic cracking process (mainly composed of C7+ olefins and aromatic compounds), a light reformate (C7/C8 aromatic compounds), an heavy reformate (C9+ aromatic compounds) and an oxygenated compound (ETBE). For each engine, tests have been run on a steady state bench with variations of some tuning parameters. Vehicle tests with the same engines have also been carried out on the European MVEG cycle, where regulated and unregulated pollutant emissions have been recorded.