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The firing frequency components of the dynamic diesel particulate filter pressure signals carry significant information about the particulate load. Specifically, the normalized magnitude and relative phase of the firing frequency components exhibit clear dependence on the particulate load in a filter. Further, the test-to-test variation and back-to-back repeatability in this work was better for the dynamic pressure signal features than for the mean value pressure drop. This work provides a promising extension or alternative to the mean value pressure drop correlation to particulate load through Darcy's Law. The results may be particularly useful for filter monitoring and control.

A fast time-scale 1-D dynamic diesel particulate filter model capable of resolving the pressure pulsations due to individual cylinder firing events is presented. The purpose of this model is to investigate changes in the firing frequency component of the pulsating exhaust flow at different particulate loadings. Experimental validation data and simulation results clearly show that the magnitude and phase of the firing frequency components are directly correlated to the mass of particulate stored in a diesel particulate filter. This dynamic pressure signal information may prove particularly useful for monitoring particulate load during vehicle operation.

The diesel particulate filter (DPF), in conjunction with fuel reformulation technologies such as ultralow sulfur fuel or Fischer-Tropsch diesel, represents a promising solution for reducing particulate emissions. In this work, membrane-coated and conventional uncoated SiC diesel particulate filters were tested on a 4-cylinder Volkswagen TDI diesel engine under four different engine load conditions at constant engine speed. Di-tert-butyl-sulfide was added to the base fuel to increase the sulfur content from 39 ppm to approximately 300 PPM. Gaseous and particulate mass emission measurements, as well as, PM morphology and composition have been used to address how engine-out and post-DPF emissions and post-oxidation catalyst emissions change with increasing fuel sulfur content. The influence of fuel sulfur on emissions was compared for the membrane coated and uncoated SiC filter using the same diesel oxidation catalyst (DOC) located downstream of the DPF.

The 2002 Pennsylvania State University FutureTruck Team has converted a stock 2002 Ford Explorer sport utility vehicle into a post-transmission, pre-transfer case parallel hybrid electric vehicle, dubbed the Wattmuncher. The stock 4.0L, V-6 spark ignition engine was replaced with a more efficient 2.5L direct-injection, common-rail, turbocharged diesel engine that meets Euro 3 emission standards. A diesel particulate filter was implemented for additional emission reductions. ADVISOR simulation results predict 23.5 mpg city and 31.9 mpg highway fuel economy while maintaining stock acceleration and towing capacity. The vehicle was designed for manufacturability, and a complete cost analysis for mass production results in an expected $4,050 added cost for this hybridized Explorer.

Diesel engine cylinder deactivation (CDA) can be used to reduce petroleum consumption and greenhouse gas (GHG) emissions of the global freight transportation system. Heavy duty trucks require complex exhaust aftertreatment (A/T) in order to meet stringent emission regulations. Efficient reduction of engine-out emissions require a certain A/T system temperature range, which is achieved by thermal management via control of engine exhaust flow and temperature. Fuel efficient thermal management is a significant challenge, particularly during cold start, extended idle, urban driving, and vehicle operation in cold ambient conditions. CDA results in airflow reductions at low loads. Airflow reductions generally result in higher exhaust gas temperatures and lower exhaust flow rates, which are beneficial for maintaining already elevated component temperatures. Airflow reductions also reduce pumping work, which improves fuel efficiency.

The latest US emission regulations require dramatic reductions in Nitrogen Oxide (NOx) emissions from vehicular diesel engines. Selective Catalytic Reduction (SCR) is the current technology that achieves NOx reductions of up to 90%. It is typically mounted downstream of the existing after-treatment system, i.e., after the Diesel Oxidation Catalyst (DOC) and Diesel Particulate Filter (DPF). Accurate prediction of input NO₂:NO ratio is useful for control of SCR urea injection to reduce NOx output and NH₃ slippage downstream of the SCR catalyst. Most oxidation of NO to NO₂ occurs in the DOC since its main function is to oxidize emission constituents. The DOC thus determines the NO₂:NO ratio as feedgas to the SCR catalyst. The prediction of NO₂:NO ratio varies as the catalyst in the DOC ages or deteriorates due to poisoning. Thus, the DOC prediction model has to take into account the correlation of DOC conversion effectiveness and the aging of the catalyst.

A gravimetric particulate measurement system, which extracts samples isokinetically from raw exhaust, is presented to quantify the particulate mass stored in diesel particulate filters. The purpose of this measurement system is to facilitate the study of wall-flow filter behavior at different particulate load levels. Within this paper, the design considerations for the particulate measurement system are detailed and its operation is described. The accuracy of the measurement is examined through a theoretical error analysis and direct experimental comparison to the differential weight of a diesel particulate filter. Experimental results are also presented to validate the ability of the system to maintain the isokinetic sampling condition.