The Influence of Improved Mixture Quality on Engine Exhaust Em issions ana Performance

Abstract

The Influence of Improved Mixture Quality on Engine Exhaust Emissions and PerformanceA large, steam-heated, fuel vaporization tank was utilized as a carburetor in multicylinder engine testing at steady-state operating conditions. In comparison to normal carburetion, the tank provided improved airfuel mixture quality, i.e., completely vaporized fuel, thoroughly mixed with air, and at elevated temperatures.Although not a practical piece of engine hardware, the tank provided a means of determining the extent of gains to be made with improved mixture quality. Improved mixture quality produced slight reductions in rich mixture hydrocarbon and carbon monoxide concentrations but did not reduce the minimum emissions of these two exhaust contaminants. Minimum fuel consumption was similarly unaffected by improved mixture quality. The most important benefit of improved mixture quality was derived from improved geometric and cyclic fuel distribution-a substantial extension of the misfire lean limit. The significance of lean limit operation and its relationship to reduced exhaust contaminants is discussed in detail.

Unburned hydrocarbon formation in a natural gas engine under sea wave load conditions

“…To explain the importance of state of matter of combustible on UHC product, Landsberg et al [27] injected liquid and evaporated gasoline fuel inside the combustion chamber and observed that the liquid fuel flow produces between three and seven times greater quantity of UHC in association with the same fuel as vapor, and this rises if this fuel is to be injected directly in to the combustion chamber. Robison and Brehob [28] used a liquid fuel vaporization carburetor to render a stronger homogeneous mixture of air and fuel. The result shows less UHC emission during warmup when liquid fuels cannot be vaporized suitably in the port and the cylinder, and regional rich mixtures occur in the combustion chamber.…”