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The design of integrated exhaust lines that combine particulate and NOx emission control is a multidimensional optimization problem. The present paper demonstrates the use of an exhaust system simulation platform which is composed of well-established multidimensional mathematical models for the transient thermal and chemical phenomena in DOC, DPF and SCR systems as well as connecting pipe heat transfer effects. The analysis is focused on the European Driving Cycle conditions. Illustrative examples on complete driving cycle simulations with and without forced regeneration events are presented for alternative design approaches. The results illustrate the importance of DOC and DPF heat capacity effects and connecting pipe heat losses on the SCR performance. The possibility of combining DPF and SCR functionality on a single wall-flow substrate is studied.

This paper presents a computational model of the transient behaviour of trap systems. The model is applicable to various driving scenarios, vehicle, engine, and trap types, as well as different trap regeneration and protection techniques. The model is synthesized from existing submodels covering the vehicle kinematics, diesel engine operation, trap operational characteristics, and the trap regeneration and protection hardware performance. The model is applied to a parametric investigation of the transient operation of the Laboratory of Applied Thermodynamics (LAT) trap oxidiser system fitted on a Mercedes 200D passenger car. The major tasks of the investigation were (a) the evaluation of the control philosophies as regards their influence on vehicle driveability, fuel consumption, and by-pass operation time, (b) the evaluation of protection techniques such as lambda-control and trap by-passing with the trap subjected to a number of failure scenarios.

The effect of three oxidation catalysts (Honeycat DEP 290, Engelhard PTX 623, Herapur 20L) and one catalytic trap oxidizer (Johnson Matthey JM 13/II) on the emissions of a RABA (M.A.N. Licensed) heavy-duty diesel engine has been comparatively studied. Tests were conducted according to EPA 13 mode test to measure CO, total HC, NOx and total particulate matter emitted by the engine with and without devices. The test results were also correlated to the total emissions of the Athenian buses through new weighing factors of an “Athenian 13 mode test”. The engine tests for all four devices resulted in: (1) considerable reduction of the engines CO and total HC emissions - being already low (2) practicaly no difference in NOx emissions and (3) increase of the total particulate emissions at high load modes.