SULEV Emissions for PC Diesel? – An integrated approach for lowest emissions

Due to the inherent high efficiency, the Diesel engine plays an important role in the European market. In specific segments, the diesel sales volumes are also increasing in the US market; combining fun to drive and excellent torque with highest efficiency. In order to stay in the market on a long term basis, solutions for SULEV emission achievement have to be developed while at the same time focusing on attractive fuel consumption.
In this paper, different aftertreatment systems are evaluated with respect to their capability to achieve the envisaged emission targets and respective efforts needed to assure acceptable warm-up characteristics. Starting up with short term solutions focusing on ULEV50 emission target we also compared two different aftertreatment concepts for SULEV fulfillment. With an eye towards best possible fuel efficiency, operating strategies are also varied in addition to the hardware specification.
In the end the chosen system including combustion concept, air- and EGR system and aftertreatment was set up on the test bed. A proper raw emission level combined with a sophisticated operating strategy for the aftertreatment system was calibrated in order to optimize lowest tailpipe emissions with excellent fuel consumption. Besides super low emission performance, such a complex system is also challenging from monitoring perspective. To address this issue, relevant requirements are evaluated in view of the chosen system.
Finally the findings of this concept study are summarized and an outlook on the next necessary steps will be given.