The Effect of Emission Control Systems and Fuel Composition on the Composition of Exhaust Gas Condensate

Condensate composition was determined for 1981–82 General Motors vehicles with a) diesel engines and no converters, b) gasoline engines with oxidizing converters, c) gasoline engines with computer command control and dual bed bead or dual bed monolith converters, and d) gasoline engines with computer command control and single bed bead converters having three-way catalysts.

The pH was found to range between 2.3 and 9.2 for the systems studied. Anions present in low pH condensates were sulfate, nitrate and chloride. Near neutral condensates and basic condensates also contained ammonia plus bicarbonate and carbonate anion, and had generally higher sulfate content than the acid condensates. Results are shown to be related primarily to differences resulting from the catalytic reduction of NO_X and fuel sulfur content.