Paul Zelenka

Worldwide diesel emission standards, current experiences and future needs

Abstract The tightening of future exhaust emission limits for diesel engines and diesel vehicles require more and more extraordinary development efforts with respect to reducing both engine-out emissions by improved combustion processes and tailpipe emissions by new exhaust gas aftertreatment systems (EGAS). Today, the main EGAS activities in engine application as well as in research and development concentrates on oxidation catalysts, particulate traps, and DENOX catalysts. This paper deals with 1. a general overview on the development directions of different EGAS and typical emission reduction examples for various diesel engine and vehicle applications; 2. the interaction between legislative emission test cycles, combustion system development and the kind of EGAS used. Based on current development work and test results, ranking considerations with regard to the application and development probability of EGAS are given.

Diesel Oxidation Catalyst Application Strategies with Special Emphasis on Odour Reduction

This paper deals with problems arising on the one hand from applying diesel oxidation catalyst for minimizing HC emission at low exhaust gas temperatures prevailing in the European city driving cycle and on the other hand in preventing sulfate formation in the oxygen catalyst at higher temperatures as they appear, e.g. in the ECE R49 13-mode certification cycle. The main parameters influencing the catalyst efficiency - exhaust gas temperature level, sulfur content in the fuel and catalyst specifications - are discussed and new solutions to fulfill the conflicting requirements are presented. 18 refs., 20 figs.

Fuel additive supported particulate trap regeneration possibilities by engine management system measures

This paper reports on the results of a joint research program performed at Rhone-Poulenc and AVL concerning a passive trap system with cerium (Ce) as a new patented fuel additive in conjunction with an engine management control system to increase the exhaust gas temperature for initiating regeneration under practically all engine application conditions. Investigations were carried out on 12L DI/TCI HD diesel engine which meets the US94 emission standards. From the work done the most effective combination of the engine patrol measures has been established as an appropriate solution to increase the exhaust gas temperature up to 400 deg. C. at minimum penalty with respect to emissions and fuel consumption. 10 refs., 17 figs., 3 tabs.