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A new vacuum-oven sublimation method (PVOS) for measuring the hydrocarbon fraction of diesel particulates has been developed to overcome problems with the standard vacuum-oven sublimation technique (VOS). VOS gave extremely low (negative at 15:1 A/F) results for diesel particulate samples taken at medium to high load (25:1 or lower A/F). The low results are due to the adsorption by the samples of trace amounts of continuously regenerated (from test samples and oven seals) heavy-hydrocarbon oven contaminants. PVOS corrects the problem by using a nitrogen gas purge to sweep hydrocarbons from the oven during testing. Comparisons among PVOS, VOS and methylene chloride extraction (MCE) over a range of A/F and engine speeds showed that PVOS results correlate more closely with MCE results than do results determined by the standard VOS technique.

A unique concept for a multi-body test rig enabling the simulation of longitudinal, steering and vertical dynamics was developed at the Institute for Mechatronic Systems (IMS) at TU Darmstadt. A prototype of this IMS test rig is currently being built. In conjunction with the IMS test rig, the Vehicle Terrain Performance Laboratory (VTPL) at Virginia Tech further developed a full car, seven degree of freedom (7 DOF) simulation model capable of accurately reproducing measured displacement, pitch, and roll of the vehicle body due to terrain excitation. The results of the 7 DOF car model were used as the reference input to the multi-body IMS test rig model. The goal of the IMS/VTPL joint effort was to determine whether or not a controller for the IMS test rig vertical actuator could accurately reproduce wheel displacements due to different measured terrain constraints.

Emissions, fuel economy, and performance are determined over a light and a heavy driving cycle designed to represent the vehicles in-use driving patterns. The vehicles are 2010 class 8 Freightliner tractor trucks equipped with Cummins engines with Selective Catalytic Reduction and Diesel Particulate Filter emission control systems. The hybrid has lower carbon dioxide emissions, better fuel economy, and nitrogen oxide emissions statistically the same as the conventional. The CO emissions are well below the standards for both vehicles, but they are higher from the hybrid. The higher CO emissions for the hybrid are primarily related to the cooling of the Diesel Oxidation Catalyst (DOC) during the standard 20 minute key-off soak between repeats of the driving cycles. With a 1 minute key-off soak the CO emissions from the hybrid are negative.