A production heavy-duty (truck) gasoline engine was equiped with both TWC single-bed and TWC dual-bed catalysts as well as a closed-loop control, stoichiometric air/fuel ratio carburetor system. The exhaust HC, CO and NOx emissions were measured on the EPA heavy-duty transient test cycle (cold start) applicable for 1984 engines. Catalyst conversion efficiencies for HC, CO and Nox of 76 %, 94 % and 77 % were achieved with the dual-bed-system. Corresponding catalyst conversion efficiencies for the TWC single-bed catalyst system were 64 %, 56 % and 79 %. At low mileage, HC/CO/NOx emissions with the dual-bed system and EGR were 0.68/3.60/0.74 gm/BHP-hr which were well below the 1984-85 Federal limits of 1.3/15.5/1.7 gm/BHP-hr.No attempt was made to optimize the various components of the total system in this program. A loss of approximately 3 % in maximum horse-power was observed relative to standard production engine. Fuel economy was unaffected. Several undesirable design characteristics of the air/fuel mixture preparation and particularly mixture distribution for this engine were identified and suggestions are made to modify the air/fuel mixing and manifold to achieve the degree of control now attained in current high-duty (passenger car) engines. (Wassmann)
The application of the three way conversion catalyst system to a heavy-duty gasoline engine
Die Anwendung des Dreiwege-Umwandlungskatalysatorsystemes bei einem Schwerlast-Benzinmotor
SAE Papers. Cumulative Index ; 1-16
1981
16 Seiten, 17 Bilder, 7 Tabellen, 32 Quellen
Conference paper
English
The Application of a Three Way Conversion Catalyst System to a Heavy-Duty Gasoline Engine
Automotive engineering | 1981
|THE APPLICATION OF A THREE WAY CONVERSION CATALYST SYSTEM TO A HEAVY-DUTY GASOLINE ENGINE
SAE Technical Papers | 1981
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