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Recent work has shown that energy efficiencies as well as yields and selectivities of the NOx reduction reaction can be enhanced by combining a plasma discharge with select catalysts. While analysis of gas phase species with a chemiluminescent NOx meter and mass spectrometer show that significant removal of NOx is achieved, high background concentrations of nitrogen preclude the measurement of nitrogen produced from NOx reduction. Results presented in this paper show that N2 from NOx reduction can be measured if background N2 is replaced with helium. Nitrogen production results are presented for a catalyst system where the catalyst is in the plasma region and where the catalyst is downstream from the plasma. The amount of N2 produced is compared with the amount of NOx removed as measured by the chemiluminescent NOx meter. The measured nitrogen from NOx reduction accounts for at least 40% of the total NOx removed for both reactor configurations.

This paper presents a simplified thermal model for round catalytic converters in steady state operation. Using this model, the analytic solution for the temperature distribution in the monolithic substrate is obtained. This analytic solution in the substrate is, then, combined with those in the intumescent mat [1] and the metal shell to obtain the temperature profile in the radial direction of the converter except for three unknown temperatures at the three material interfaces, which can be solved using an Excel application program. This analytical temperature solution facilitates the studies of the effects of various design parameters such as the exhaust gas temperature, exhaust gas flow rate, substrate cell geometry, converter dimensions, and ambient temperature and flow, etc.

Sustained NOx reduction at low temperatures, especially in the 150-200 °C range, shares some similarities with the more commonly discussed cold-start challenge, however, poses a number of additional and distinct technical problems. In this project, we set a bold target of achieving and maintaining 90% NOx conversion at the SCR catalyst inlet temperature of 150 °C. This project is intended to push the boundaries of the existing technologies, while staying within the realm of realistic future practical implementation. In order to meet the resulting challenges at the levels of catalyst fundamentals, system components, and system integration, Cummins has partnered with the DOE, Johnson Matthey, and Pacific Northwest National Lab and initiated the Sustained Low-Temperature NOx Reduction program at the beginning of 2015 and completed in 2017.

The destruction of low concentrations (<600 ppm) of nitric oxide using a low-temperature, dielectric barrier/packed-bed corona reactor has been studied. We compare the chemistry and energy efficiencies observed using various packing materials in warm moist air under oxidative (lean-burn) conditions. Measurements of NO and NOx removal in the effluent gas were made as a function of energy dissipated in the reactor. Changes in the observed fate of NO as a function of the packing material are discussed.

This paper describes a program to develop a miniaturized chemical laboratory (μChemLab™). This system includes multiple analysis channels each with microfabricated sample collectors/concentrators, gas chromatographic separators, and chemically selective detectors based on an array of coated surface acoustic wave devices. This development effort is currently focused on fabricating small (palm-top computer sized), lightweight, and autonomous systems that provide rapid (1 min), sensitive (1-10 ppb), and selective detection of chemical warfare agents. The small size and low power of the μChemLab™ technology make it potentially useful for monitoring of compounds such as volatile organic compounds (VOCs), ammonia, and formaldehyde in space environments.

This paper first reports on the benchmarking of a gasoline- fueled vehicle currently for sale in California that is certified to ULEV standards. Emissions data from this vehicle indicate the improvements necessary over current technology to meet SULEV tailpipe standards. Tests with this vehicle also show emissions levels with current technology under off-cycle conditions representative of real-world use. We then present Delphi's strategy of on-board partial oxidation (POx) reforming with gasoline-fueled, spark-ignition engines. On-board reforming provides a source of hydrogen fuel. Tests were run with bottled gas simulating the output of a POx reformer. Results show that an advanced Engine Management System with a small on-board reformer can provide very low tailpipe emissions both under cold start and warmed-up conditions using relatively small amounts of POx gas. The data cover both normal US Federal Test Procedure (FTP) conditions as well as more extreme, off-cycle operation.

In this paper we discuss in detail an algorithm that addresses cylinder-to-cylinder imbalance issues. Maintaining even equivalence-ratio (ϕ) control across all the cylinders of an engine is confounded by imbalances which include fuel-injector flow variations, fresh-air intake maldistribution and uneven distribution of Exhaust Gas Re-circulation (EGR). Moreover, in markets that are growing increasingly cost conscious, with ever tightening emissions regulations, correcting for such mismatches must not only be done, but done at little or no additional cost. To address this challenge, we developed an Individual Cylinder Fuel Control (ICFC) algorithm that estimates each cylinder's individual ϕ and then compensates to correct for any imbalance using only existing production hardware. Prior work in this area exists1,2, yet all disclosed production-intent work was performed using wide-range oxygen sensors, representing cost increases.

We present data in this paper showing that non-thermal plasma in combination with heterogeneous catalysis is a promising technique for the treatment of NOx in diesel exhaust. Using a commonly available zeolite catalyst, sodium Y, to treat synthetic diesel exhaust we report approximately 50% chemical reduction of NOx over a broad, representative temperature range. We have measured the overall efficiency as a function of the temperature and hydrocarbon concentration. The direct detection of N2 and N2O when the background gas is replaced by helium confirms that true chemical reduction is occurring.