Effects of 8Ч12/12 catalytic converter prestarting on harmful emissions at negative ambient temperatures

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We consider the possibility of reducing the harmful emissions of diesel engines at negative ambient temperatures by using preheater exhaust gas heat recovery to sustain the thermal parameters of gas cleaning in the catalytic converter. At starting, idling, or low loads, the unheated neutralizer is inefficient, which is why the catalytic-converter bricks have to be preheated during prestarting from the ambient temperature to its optimal operating temperature for efficient gas cleaning. It has been revealed that the composition of exhaust gases of a diesel engine depends on the ambient-air temperature. We have estimated the harmful emissions of nitrogen oxides, hydrocarbons, carbon monoxide, and particulates at 241…248…264…273…298 K and compared them to such standards as UN ECE EURO-3, EURO-4, and EURO-5. Studying of the changes in the emissions resultant from the exhaust of a 8Ч12/12 diesel engine has revealed that reducing the ambient temperature from 298 K to 241 K increases the emission of nitrogen oxides 1.07 times, while also reduce the carbon monoxide emission 1.59 times, the total hydrocarbon emissions 2.46 times, and particulate emissions 1.57 times. During preheating, as the catalytic-converter bricks are heated from 250 K to 833 K, the converter reduces the emissions of nitrogen oxides 3.73 times, the emissions of hydrocarbons 12.75 times, the carbon monoxide emissions 2.5 times, and particulate emissions 3 times. Heating the bricks to 833 K while starting the diesel engine reduces its harmful emissions by 52% in terms of nitrogen oxides, by 86% in terms of carbon monoxide, by 67% in terms of hydrocarbons, and by 85% in terms of particulate matter.