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Many excellent papers have been written about the subject of estimating engine-out NOx on diesel engines based on real-time available data. The claimed accuracy of these models is typically around 6-10% on validation data sets with known inputs. This reported accuracy typically ignores input uncertainties, thus arriving at an optimistic estimate of the model accuracy in a real-time application. In our paper we analyze the effect of input uncertainty on the accuracy of engine-out NOx estimates via a numerical Monte Carlo simulation and show that this effect can be significant. Even though our model is based on an in-cylinder pressure sensor, this sensor is limited in its capability to reduce the effect of other measured inputs on the model.

Stringent global emissions legislation demands effective NOx reduction strategies, particularly for the aftertreatment, and current typical liquid urea SCR systems achieve efficiencies greater than 90% [1]. However, with such high-performing systems comes the trade-off of requiring a tank of reductant (urea water solution) to be filled regularly, usually as soon as the fuel fillings or as far as oil changes. Advantages of solid reductants, particularly ammonium carbamate, include greater ammonia densities, enabling the reductant refill interval to be extended several multiples versus a given reductant volume of urea, or diesel exhaust fluid (DEF) [2]. An additional advantage is direct gaseous ammonia dosing, enabling reductant injection at lower exhaust temperatures to widen its operational coverage achieving greater emissions reduction potential [3], as well as eliminating deposits, reducing mixing lengths, and avoiding freeze/thaw risks and investments.

Interior parts that are composed of plastic usually deform under various temperature conditions. It is necessary to obtain the material properties for an analysis of the thermal deformation under the heat cycle test. Specifically, creep data of plastic material was introduced for studying the time-dependent deformational behavior of the pillar trim in the heat cycle test. The time-hardening version of the power-law creep model was applied to account for the permanent deformation following the heat cycle test, which was verified through a comparison of the test results with the result of finite-element analysis for a simple model. In this study, a methodology was developed for the optimal design of the A-pillar trim in terms of the positions of the mounts. The analyzed results were used to approximate a function that was constructed by the response-surface method. Design procedures were repeated to minimize the thermal deformation at the areas of interest.

The liquid fuel film on the cylinder liner is believed to be a major source of engine-out hydrocarbon emissions in SI engines, especially during cold start and warm-up period. Quantifying the liquid fuel film on the cylinder liner is essential to understand the engine-out hydrocarbon emissions formation in SI engines. In this work, the fuel film formation model was developed to investigate the distribution of wall fuel film on the cylinder wall of an SI engine. By integrating the continuity, momentum, and energy equations along the direction of fuel film thickness the simulation of the fuel film formation was carried out in the test rig. Spray impingement and fuel film models were incorporated into the computational fluid dynamics code, STAR-CD to calculate fuel film thickness and distribution of fuel film on the cylinder wall. With a laser-induced fluorescence method, the two-dimensional visualization of liquid fuel films was carried out to validate the simulation results.

The liquid fuel film on the cylinder liner is believed to be a major source of engine-out hydrocarbon emissions in SI engines, especially during cold start and warm-up period. Quantifying the liquid fuel film on the cylinder liner is essential to understand the engine-out hydrocarbon emissions formation in SI engines. In this research, two-dimensional visualization was carried out to quantify liquid fuel film on the quartz cylinder liner in an SI engine test rig. In addition, comparing visualization results with the trend of hydrocarbon emissions in this engine, the effect of cylinder wall-wetting during a simulated cold start and warmed-up condition was investigated with the engine experiment. The visualization was based on laser-induced fluorescence and total reflection. Using a quartz liner and a special lens, only the liquid fuel on the liner was visualized.

In this paper, the general effects of the regeneration parameters, such as initial particulate loading, space velocity, oxygen concentration and inlet gas temperature, on the combustion of the particulate matter (PM) filtrated in the ceramic filter of a diesel particulate filter (DPF) system are considered experimentally. A new method to control the combustion rate of the PM during regeneration is also studied for the protection of the ceramic cordierite filter. It controls the temperature of gas entrained into the filter during re-generation, which was previously not considered as a controllable factor in the vehicle[1, 2, 3, 4 and 5]. Control of gas temperature was achieved by controlling the flow rate of engine exhaust gas entrained into the filter during regeneration.