Methanol Vaporization: Effects on Volumetric Efficiency and on Determination of Optimum Fuel Delivery System

摘要

The hypothesis of this study was 'Can methanol injected into the upstream air passages (additionally to the normal port injection) cool the inlet air sufficiently through vaporization to increase the volumetric efficiency, and will the expected increase in volumetric efficiency translate into improved thermal efficiency.' This hypothesis is derived from the mathematical equation of volumetric efficiency in which the efficiency is proportional to the mass of air per unit of time flowing through the engine relative to the swept volume of the engine during that time. Vaporization (through fumigation) in the inlet air should cause a temperature drop of the air, which would increase density and mass flow. To test this hypothesis, two methods of fumigation were tested, both occurring along with the normal port injection of the Nissan 2.0 litre NAPS-Z engine. Neither method improved volumetric or thermal efficiency. In fact, the normal port injection without fumigation gave slightly better results. Because none of the fumigation systems tested demonstrated any increase in efficiency at the lower power levels tested, EPA recommended that any plans for fumigation testing on this engine in the future be discontinued.