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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.

A ceramic trap forced regeneration system for urban buses and passenger cars, capable of safe and reliable on-road regeneration is presented in this paper. Development of this system has been made possible through the application of two main design aims: The possibility of protecting the trap from overheating by use of a trap bypassing technique, and the reduction of the total mass of intervening parts between engine and trap, so as to improve trap temperature transient response.

A method for the determination of the size of the ceramic trap according to the engine and its use, has been developed. The calculation algorithm is presented, based on fundamental considerations concerning trap operation during regeneration and accumulation, and taking into account the parameters imposed by the engine. The application of the method is then presented, with the example of engines from within the range of 30-300 kW rated power. A module configuration of the trap oxidiser consisting of a number of Corning EX 47, 5.66″ × 6″ filter elements is used.

A Diesel particulate trap oxidiser system suitable for retrofiting on urban buses is described. The system consists of a ceramic trap, a regeneration device and a control unit. The system is based on a new forced regeneration technique, by means of exhaust gas throttling. This technique establishes regeneration conditions on the road by the engine itself, with-out any external source of thermal energy or catalyst. Two buses in use with the Athens Public Transport Company (EAS) have been equipped with this system. The buses have been tested under real conditions on Athens urban bus routes and the results after the first 10000 km of operation are presented.

A regeneration system for the ceramic trap oxidiser is presented, based on the exhaust gas throttling of the engine. The trottling process, producing 1.5-3.0 bar overpressure, leads to a modified power flow in the engine, resulting in higher enthalpy exhaust gas, at the expense of the net power output of the engine. Thus exhaust temperature is raised over the lower regeneration limit (550°C) for a wide range of engine operation modes including also high speed-no-load modes. The effects of throttling on exhaust gas thermodynamic state and engine operational characteristics (volumetric efficiency, mean effective pressure, power output, consumption) are theoretically and experimentally analysed. An optimised regeneration system by exhaust throttling is described. This system includes: regulated throttling orifice for minimum net power output loss and reduction of fuel injected for acceptable smoke emission of the engine under high backpressure conditions.