Abstract An overview is presented of the effect of emission control on requirements for gasoline and the performance of engines in three categories: fuel economy, emissions profile, and driveability. Three levels of emission control have been considered: precontrol, intermediate levels of control obtainable with engine modifications and exhaust gas recirculation, and advanced emission control requiring catalytic systems.
The discussion is limited to the conventional, spark ignited piston engine (Otto cycle), which, at least for the near term future, will continue to be the dominant automobile power plant.
Résumé On présente une revue de l'effet du contrôle des émissions sur les exigences d'essence et les performances de moteurs, suivant trois catégories de paramètres: l'économie d'essence, le profile des émissions, et l'efficacité d'opération de l'automobile. Trois niveaux de contrôle d'émissions ont été considérés: précontrôle; niveau intermédiare tel que celui obtenu par modification du moteur et recirculation des gaz d'échappement; et contrôle d'émissions avancé obtenu avec des systèmes catalytiques. La discussion est limitée au moteur conventionnel, à combustion interne et allumage par bougies (cycle d'Otto), qui, au moins pour le future prochain, sera la propulseur dominant des automobiles.
1. INTRODUCTION Prior to the introduction of emission control regulations, automobiles were designed to provide a balance between good fuel economy and good performance. The gasolines required by these vehicles could be defined primarily in the classic terms of octane quality, volatility characteristics and engine cleanliness. The chemical composition of gasoline was of concern as it affected the octane, volatility, or cleanliness parameters of the fuel.
In the late 1960s emission control regulations changed this picture. Automobile manufacturers faced well defined emission standards which had to be met prior to any attempt to optimise either the fuel economy or driveability of their vehicles. The regulations also created new requirements for gasoline. It by N. V. HAKALA, D. G. LEVINE, Exxon Research and Engineering Company, P.O. Box 101, Florham Park, New Jersey 07932, U.S.A., M. CAMARSA, Esso Europe, Inc., Italy, and R. SIERING, Esso A.G., Federal Republic of Germany had to be compatible with emission control systems For example, the catalytic control systems now available require lead-free gasoline. The role of the chemical composition of gasoline in determining the emission profile of a vehicle also became a major concern. This profile consists of the mass emissions of carbon monoxide (CO), hydrocarbon (HC), and oxides of nitrogen (NO,), the reactivity of the hydrocarbons emitted, and the amounts of unregulated emissions such as oxygenated hydrocarbons, polynuclear aromatics, and particulates.
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