Three-way catalytic muffler using progressive air injection for automotive exhaust gas purification. SAE Paper 700298

Conference · Sat Jan 01 04:00:00 EST 1977

OSTI ID:7052974

Prigent, M; Raynal, B; Courty, P

The simultaneous removal of the three types of pollutants (NO, CO, and HC) with a single catalytic muffler is possible without requiring a very precise adjustment of the engine equivalence ratio or permanent control of the supply of secondary air added ahead of the muffler. The system studied consists of a muffler in which secondary air is supplied from a plurality of points located within the catalyst bed itself in order to have an oxygen concentration in the treated gas that increases progressively between the inlet and the outlet. Experimental muffler designs are presented for monolithic or bead-type catalysts. The numerous advantages of this technique as compared with the well-known dual bed system are described. It is in particular shown that the NO reduction rate is increased on precious metal catalysts when oxygen is added to some extent in a reducing exhaust gas, with maximum efficiency being reached just below the stoichiometric proportion. Ammonia formation due to the presence of oxygen is also reduced in the first part of the catalytic bed, and its reoxidation in the oxidizing section is directed toward N/sub 2/ formation since oxygen is only in large excess near the outlet. The results of several tests made on an engine bench, show that the ratio between the flow of exhaust gas and secondary air may vary widely with little change in the efficiency of the muffler. Some data obtained on a vehicle, using the CVS procedure, confirm these results.

• OSTI ID: 7052974
• Report Number(s): CONF-770205-85
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
330101 -- Internal Combustion Engines-- Spark-Ignition
330700* -- Advanced Propulsion Systems-- Emission Control
AIR POLLUTION CONTROL
AUTOMOBILES
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CATALYTIC CONVERTERS
CHALCOGENIDES
DATA
ELEMENTS
ENGINES
EQUIPMENT
EXHAUST GASES
EXPERIMENTAL DATA
FLOW RATE
FLUIDS
GASEOUS WASTES
GASES
HEAT ENGINES
HYDROCARBONS
INFORMATION
INTERNAL COMBUSTION ENGINES
NITROGEN COMPOUNDS
NITROGEN OXIDES
NONMETALS
NUMERICAL DATA
OPERATION
ORGANIC COMPOUNDS
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PERFORMANCE
POLLUTION CONTROL
POLLUTION CONTROL EQUIPMENT
VEHICLES
WASTES