Impacts of Biodiesel, Fuel Additive, and Injection Pressure on Engine Emission and Performance

Abstract

A major concern today is the environmental pollution by the emission of gases from vehicles. Biodiesel is a cleaner alternative to petroleum diesel in terms of carbon monoxide (CO), hydrocarbon (HC), and smoke emission. However, biodiesel results in higher nitrogen oxide (NOx) with increasing performance, poor cold weather properties, and relatively low brake-thermal efficiency (BTE), which sets a major disadvantage for its worldwide commercialization. The impact of biodiesel fatty acid contents was studied through various blends of biodiesel so as to discover the optimum fatty acid content for reduced NOx emission and sufficient brake-thermal efficiency. Glycerol tert-butyl ether (GTBE) is a transesterification by-product and a fuel additive that has the potential to serve these issues. Instead of increased BTE maximum, a 10.5% reduction in NOx yield was observed with modified injection pressure and 2.5% GTBE concentration. Modified injection pressure of 240 bar (24 MPa) and 5% GTBE resulted in a maximum of 20% cut in CO emission. All tested biodiesel fuels displayed a decrease in NOx emission with improved BTE at 2.5% and 5% GTBE addition. Injection pressure 220 bar and 240 bar in combination with GTBE enhanced BTE of fuels significantly.