The effect of diesel engine cold start period on the emitted emissions [ ]

Diesel engines emit pollutants from their exhaust that cause environmental pollution reached minutes stages. The attention has in-creased by reducing the burning of fossil fuels, especially diesel pollution rates, worldwide. The engine startup process can be considered as a complicated operation of the engine that causes high pollution rates. In this research study, the pollutants emitted from direct injection, four cylinders diesel engine during the startup period was measured and analyzed in the conditions of low temperatures of the winter in Baghdad, Iraq. The effect of engine starting speed was examined to evaluate the impact of engine starting speed on the emitted emissions. The results showed high levels of carbon monoxide and unburned hydrocarbons and lower carbon dioxide. Also, the nitrogen oxides in the exhaust gasses have emerged despite the cold operation. The smoke opacity rose at starting speed of 800 rpm, as well as, the engine noise increased at this speed compared to the rest velocities.