The Effect of Very Low Air Intake Temperature on the Performance and Exhaust Emission Characteristics of a Diesel Engine

Abstract

Operational and exhaust emission characteristics of a single cylinder direct injection diesel engine are described. It was operated warm under a wide range of intake air temperatures extending down to -45 F and occasionally -60 F. The smoke density increased at the very low load range mainly associated with the greater production of aerosol or cold smoke. At lower intake temperature, this increase at light load and partial motoring range became particularly high despite the increased mass of air being induced. For the low load range, the exhaust was almost totally opaque at subzero temperatures. The concentration of carbon monoxide under very light load or partially motored conditions associated with cold or aerosol smoke emissions was many times that observed for the same engine at higher loads. The nitrogen oxides exhaust emission for any fueling rate decreased significantly with the reduction of intake temperature. The concentration of nonutilized oxygen in the exhaust gas for any fueling rate increased with the lowering of intake temperature, reflecting the deterioration of fuel utilization and increased mass flow with a reduction of temperature.