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Alternative automotive engine oil filtration devices are described herein, aiming at alleviating the environmental issues caused by conventional one-piece, spin-on, throwaway filters. The spin-on feature has been retained in these novel filters, to facilitate retrofitting, however provisions to dismantle the filter have been incorporated to allow for periodic replacement of the filter element (cartridge). The filter element is made of ceramic powder and, upon replacement, it may be treated and reused as such, or it may be crushed, treated and remanufactured from the recycled powder. In the process, the entirety of the used motor oil may be retrieved, treated and reused, thus conserving energy and resources, minimizing waste streams and, most importantly, preventing environmental ground-water contamination.

The simultaneous control of diesel engine particulate and NOx emissions was targeted in this study. Particulate control was achieved with a trap that incorporated a high-filtration efficiency ceramic honeycomb monolith. Aerodynamic regeneration was used to periodically backflush the monolith filter. Soot was collected in a metallic chamber and was either incinerated by an electric burner or removed by a vacuum cleaner. NOx emissions were reduced by recirculation of filtered exhaust gases (EGR), which was made possible by the high collection efficiency of the employed monoliths. Tests were conducted on the road, driving a diesel vehicle under various loads and speeds. The levels of NO, CO and O2 at the exhaust were continuously monitored using a portable instrument. The particulate filtration efficiency was in the vicinity of 99% using CeraMem and 97-98% using Panasonic traps, respectively, hence the EGR line was effectively particulate-free.

This is an optimization study on the use of filtered exhaust gas recirculation (EGR) to reduce the NO emissions of diesel engines. Control of the particulate emissions and provisions for filtered EGR were achieved by an Aerodynamically Regenerated Trap (ART) with collection efficiencies in the order of 99%. The amount of EGR was regulated to provide for substantial NO reduction, without unacceptably decreasing the thermal efficiency of the engine or increasing the CO emissions. EGR regulation was accomplished by monitoring the injection pump setting which was correlated to the fuel flow rate, the speed of the engine, the amount of EGR flow, and the ambient air temperature. Through these parameters, the mixture strength expressed as the equivalence ratio, ϕ, was calculated and related to the power output of the engine. Thus, a map of engine performance parameters was generated and related to measured NO and CO emissions.

New developments for optimized control of Aerodynamically Regenerated Traps (ART) - Exhaust Gas Recirculation (EGR) integrated systems for diesel engines are presented herein. Such systems employ high-efficiency ceramic monolith filters to retain 99% of the emitted particulates. Regeneration is achieved periodically by short pulses of compressed air, flowing in the opposite direction to the exhaust. The soot is collected in a chamber, outside of the monolith, where it is oxidized with an electric burner. A fraction of the filtered exhaust is returned to the engine and this reduces NOx emissions, typically, by more than 50% at 18% EGR. However, since the amount of EGR, the frequency of regeneration and the frequency and duration of burning have a bearing on the fuel consumption of the engine, their optimization is imperative. Thus, provisions were made to collect intelligent information, leading to continuous assessment of the engine performance and fuel economy.

This manuscript describes laboratory tests and calculations that explore the effectiveness of a stream of ionized air to oxidize soot and, thus, regenerate diesel particulate filters. Soot was oxidized inside a muffle furnace in two different configurations, either as a layer of soot spread in a porcelain boat, or as a quantity of soot evenly loaded in a ceramic wall-flow monolith. Oxidation took place in air, ozone-enriched air or air ionized by an electric arc (thermal plasma), at furnace temperatures in the range of 200-450° C. It was found that when ozone was generated in the inlet air (1060 ppm) the consumption rate of soot increased by up to ten percent. However at the presence of the thermal plasma (generating O, NO2, NO, and O3) the carbon consumption was accelerated by factors varying from a few percent to often exceeding one hundred percent. The effectiveness of this technique depended on the characteristics of the arc.

This work determined the suitability of two silicon carbide (SiC) monoliths (one regular and one coated with a micromembrane), as well as a coated cordierite monolith for use as aerodynamically regenerated particulate filters for diesel engines. These ceramic honeycomb monoliths were tested for their filtration efficiency, their post filtration particulate size distribution and their ability to be aerodynamically regenerated at pre-selected operating temperatures (200, 300 and 400°C). Through combined laboratory and field testing, the uncoated silicon carbide filter produced the most satisfactory results in all of these tests. This filter resulted in excellent regeneration characteristics while maintaining the highest filtration efficiencies at all particle sized tested. All filters were found to clean effectively at all temperatures. However, upon normalization with the volumetric flow rate through the monolith, it was found that the filters were most thoroughly cleaned at 400°C.