Catalytic automotive exhaust gas depollution: Present status and new trends

A review is made of the various types of exhaust gas aftertreatment systems presently used on most vehicles to reduce pollutant emissions. The systems are differentiated by their mode of action, according to the engine type to be depolluted (2-strokes, 4-strokes, diesel or spark-ignition), and by their type of make-up. The major developments foreseen in the future, in view of compliance with the new legislations, are described. Means enabling some prototype vehicles with internal combustion engines to emit pollutant quantities really close to zero, such as electric cars, are described.