Bruce B. Bykowski

Development of a Methodology to Separate Thermal from Oil Aging of a Catalyst Using a Gasoline-Fueled Burner System

Typically, an engine/dynamometer thermal aging cycle contains combinations of elevated catalyst inlet temperatures, chemical reaction-induced thermal excursions (simulating misfire events), and average air/fuel ratios (AFRs) to create a condition that accelerates the aging of the test part. In theory, thermal aging is predominantly a function of the time at an exposure temperature. Therefore, if a burner system can be used to simulate the exhaust AFR and catalyst inlet and bed temperature profile generated by an engine running an accelerated aging cycle, then a catalyst should thermally age the same when exposed to either exhaust stream. This paper describes the results of a study that examined the aging difference between six like catalysts aged using the Rapid Aging Test (RAT) cycle (an accelerated thermal aging cycle). Three catalysts were aged using a gasoline-fueled engine aging stand; the other three were aged using a computer controlled burner system. Both systems were programmed to run aging cycles that provided the same inlet temperature and AFR profiles, and space velocity conditions. Each catalyst was evaluated using a vehicle over the FTP emissions test cycle and an AFR sweep test suing an engine test stand before and after aging. Finally, the catalysts were cored and analyzed to provide a composition and surface area comparison. BACKGROUND

Simultaneous Reduction of Diesel Particulate and NOx Using a Plasma

A non-thermal plasma treatment of diesel engine exhaust was effective in removing particulate (soot) and oxides of nitrogen (NO{sub x}) from two different light-duty diesel vehicles: an older-technology indirect-injection Toyota truck, and a newer-technology direct-injection Dodge truck. Particulate removal efficiencies and NO{sub x} conversion efficiencies were determined at space velocities up to 20,000/hr. Particulate removal efficiencies were above 60 percent for most conditions, but decreased with increasing space velocities. Conversion efficiencies for NO{sub x} and carbon monoxide (CO) were also dependent on the space velocity. The NO{sub x} conversion efficiencies were generally greater than 40 percent at space velocities less than 7000/hr. The CO concentration increased through the plasma reaction bed indicating that CO was produced by reactions in the plasma. In general, the results from these tests showed that the plasma reaction bed was capable of reducing both particulates and NO{sub x} simultaneously, a result which has not been demonstrated with any other single technology. 6 refs., 6 figs., 5 tabs.

COMPARISON OF PETROLEUM AND ALTERNATE-SOURCE DIESEL FUEL EFFECTS ON LIGHT-DUTY DIESEL EMISSIONS

Exhaust emission data from several fuel effects studies were normalized and subjected to statistical analyses. The goal of this work was to determine whether emission effects of property variation in alternate-source fuels were similar, less pronounced, or more pronounced than the effects of property variation in petroleum fuels. A literature search was conducted, reviewing hundreds of studies and finally selecting nine which dealt with fuel property effects on emissions. From these studies, 15 test cases were reported. Due to the wide variety of vehicles, fuels, test cycles, and measurement techniques used in the studies, a method to relate them all in terms of general trends was developed. Statistics and methods used included bivariate correlation coefficients, regression analysis, scattergrams and goodness-of-fit determinations. Insertion of alternate-source fuel properties into exhaust emissions prediction equations based on petroleum fuel results indicated that the effects of alternate-source fuel property changes on exhaust emissions were statistically indistinguishable from those associated with petroleum fuels.