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This paper describes recent progress in our program to develop an emissions technology allowing diesel engines to meet the upcoming 2007/2010 regulations for NOx. At the heart of this technology is the ArvinMeritor Diesel Fuel Reformer that reforms the fuel, on-demand, on-board a vehicle. The fuel reformer uses plasma to partially oxidize a mixture of diesel fuel and air creating a highly reducing mixture of Hydrogen and Carbon monoxide. In a previous publication, we have demonstrated that using a reformate rich in H2 and CO to regenerate a NOx trap is highly advantageous compared to vaporized diesel fuel used conventionally. In this paper we present results and a strategy for performing desulfation of the traps using the fuel reformer. In contrast to vaporized diesel, which requires very high temperatures that fall outside the normal exhaust operating temperatures for diesel engines, desulfation was achieved at temperatures lower by more than 100 °C using the Plasma Fuel Reformer.

An active diesel particulate filter regeneration system has been developed to remove diesel particulate matter (PM) accumulation from diesel particulate filters. Diesel particulate filters (DPF) are an effective means of significantly reducing PM emissions from vehicles powered by diesel engines. This paper outlines the use of the ActiveClean™ Thermal Regenerator (TR) system to reduce PM emissions in several different applications. Test cell data was collected using a 15.8L diesel engine to provide exhaust flow. The objective of this test was to evaluate the steady state HC, CO and NOx emissions of the engine and TR combination during regeneration of the filter. The data reveals only a slight increase in HC and CO emissions depending on configuration (single-or dual-leg) for steady state regenerations. It also showed that the TR had very little impact on NOx emissions during regeneration.

This paper describes recent progress in our program to develop an emissions technology allowing diesel engines to meet the upcoming stringent worldwide regulations for NOx. The Plasma Fuel Reformer (PFR) has the ability to rapidly convert diesel fuel (with air), to a hydrogen rich gas on-board a vehicle, which is then utilized to efficiently regenerate a NOx trap. We have made several advances on the PFR as well as on the NOx reducing system. The Plasma Fuel Reformer operating range has been extended by 120% up to 1.5 g/s fuel flow rate while retaining the high hydrogen and low soot characteristics. The plasma power consumption has been further reduced and the high voltage design has been made more robust. The T90 start-up time during regenerations has been reduced to less than 4 seconds. The NOx reducing system utilizes a novel algorithm for NOx trap regeneration that reduces the fuel penalty by 25% while increasing NOx conversion by 10%.

A Diesel Particulate Filter (DPF) is needed to meet the Particulate Matter (PM) requirements of US EPA 2007 regulations for diesel engines. A catalyzed diesel particulate filter (cDPF or CSF) in combination with a diesel oxidation catalyst (DOC) is effective if the DOC has achieved light-off. However, for some applications, exhaust temperature will be too low to achieve DOC light-off. Therefore a reliable active regeneration means will be required. This paper presents a diesel-fired filter regenerator that works with an uncoated DPF. During regeneration, the thermal regenerator raises the exhaust temperature to 650 °C at the filter face at any engine condition, including idle. The thermal regenerator was tested on a cordierite filter placed on a heavy-duty diesel engine with cooled-EGR (2007 calibrations). THC, CO and NOx emissions, as well as opacity, in the tailpipe were measured at both steady state and transient engine conditions.

In recent years, several transit agencies have tested buses equipped with hybrid powertrain systems. It has been reported that hybrid powertrains have significant advantages over conventional diesel engine systems, in the area of emissions and fuel economy performance. Presented in this paper are engineering issues and suggestions from an auto component supplier point of view in the design of such a powertrain system. The particular system being considered consists of a downsized diesel engine, a generator, a battery package, two identical AC induction motors, and gearbox systems for the left and right driven wheels. The assembly is supported by an H-shaped suspension sub-structure uniquely designed to achieve the “ultra-low floor” configuration. Our discussion covers the system performance, as well as the durability issues. In particular, the presentation focuses on the durability and the design layout of the gearbox and suspension substructure.