What Causes the Pungent Smell in Car Exhaust?

[OAriana]

Car exhaust emits a pungent smell due to the following reasons: 1. Poor fuel quality. Gasoline contains too many impurities, heavy metals, and moisture, resulting in foul-smelling exhaust emissions. 2. Incomplete combustion of the air-fuel mixture. The primary cause of incomplete combustion is an overly rich air-fuel mixture. On one hand, this generates a large amount of carbon monoxide and free carbon particles in the cylinders, which can impair the purification capability of the catalytic converter. On the other hand, some unburned mixture is also expelled with the exhaust, intensifying the odor. 3. Faulty catalytic converter. The catalytic converter typically experiences three types of issues: poisoning (sulfur, phosphorus, manganese, lead, and carbon monoxide in fuel and lubricants can poison and deactivate the catalyst), clogging (usually caused by carbon deposits), and internal ceramic damage (often occurring when the vehicle passes over speed bumps or small inclines).