The effects of low-lead and unleaded fuels on gasoline engines. Effects of low-lead and unleaded fuels on gasoline engines. SAE Technical Paper Series. International Congress and Exposition [24-28 Feb. 1986 : Michigan].

Weaver, Christopher S.

1986

2080
CIENA

The U.S. Environmental Protection Agency has recently reduced the permissible concentration of lead in gasoline from 1.1 to 0.1 gramper gallon, and has proposed to eliminate lead entirely by 1988. In addition to its octane-enhancing properties, lead in gasoline protects exhaust valve seats in older engines from undue wear (valve-seat recession), an it and its acabvengers have numerous other positive and negative effects. These include changes in octane requirements, hydrocarbon emissions, engine rusting, corrosive wear, oil thickening and degradation, spark-plug fouling, exhaust-valve burning, and exhaust system corrosion. This paper reviews the literature on the harmful and beneficial effects of lead and lead scavengers on engines, and examines some of the substantial body of operating experience that has been accumulated with unleaded gasoline in older engines. Based on this experience, it does not appear that valve-seat recession will be a major problem, even if all lead is eliminated from gasoline. Furthermore, the switch to unleaded gasoline should provide significant benefits in the form of reduced maintenance costs and increased engine life. The U.S. Environmental Protection Agency has promulgated rules which will limit the lead content of gasoline to no more than 0.1 gram of lead per gallon, beginning in January, 1986. At the same time, EPA proposed a complete ban on the use of lead in gasoline, to become effective in 1988 (1). These actions have created a great deal of concern among automotive engineers and the general public over the possible effects of very low-lead or unleaded gasolines on engines which were designed for use with conventionally leaded fuel. This paper summarizes the results of a series of EPA-funded studies (2-6) of the potential effects of low-lead and unleaded gasolines on engines designed for leaded fuel. These studies included a careful examination of the relationships between lead additives and valve seat protection and a thorugh review of the other effects of lead and lead scavengers on engines. Other topics examinated in these studies included the effects of unleaded fuels on engines in heavy-duty trucks, agricultural equipment, inboard marine engines, and motorcycles. Considerable effort has gone into identifying vulnerable engines and engine types. In addition, a great deal of information on experience with unleaded fuel in engines in consumer use (as opposed to laboratory dynamometer studies) has been gathered. The results of these studies are summarized here in three sections. The first section is a review of the applicable literature, focussed primarily on laboratory results. The second section discusses in-use experience with unleaded gasoline in engines designed for leaded fuel. The third section presents the results of the effort to identify vulnerable engines in heavy-duty trucks and agricultural equipment..

Presenta gráfs

ESTADOS UNIDOS; GASOLINA SIN PLOMO; COMBUSTIBLES SIN PLOMO; MOTORES DE GASOLINA; VENTAJAS; COSTOS; DESVENTAJAS; RESULTADOS DE INVESTIGACION; EQUIPO AGRICOLA;