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Regulations have been established for the monitoring and reporting of greenhouse gas (GHG) emissions and fuel consumption from the transport sector. Low carbon fuels combined with new powertrain technologies have the potential to provide significant reductions in GHG emissions while decreasing the dependence on fossil fuel. In this study, a lean-burn ethanol-diesel dual-fuel combustion strategy has been used as means to improve upon the efficiency and emissions of a conventional diesel engine. Experiments have been performed on a 2.0 dm3 single cylinder heavy-duty engine equipped with port fuel injection of ethanol and a high-pressure common rail diesel injection system. Exhaust emissions and fuel consumption have been measured at a constant engine speed of 1200 rpm and various steady-state loads between 0.3 and 2.4 MPa net indicated mean effective pressure (IMEP).

A corona discharge device (CDD) used in conjunction with automotive stoichiometric catalysts has been shown to be effective in reducing exhaust tailpipe emissions and catalytic converter light-off temperatures. The CDD used here is a low power, low cost corona discharge device mounted ahead of the catalytic converter in the exhaust stream. Creation of radicals and other oxidizing species in the exhaust by the non-thermal plasma is shown to significantly improve catalyst conversion efficiencies for HC, CO and NOx. Burner flow data shows improvement in steady-state conversion efficiencies as well as improved catalyst light-off performance. Engine-dynamometer and vehicle data on spark ignition engines using production type (stoichiometric) control also shows improved performance with aged catalysts, and various levels of fuel sulfur. The reversibility of sulfur poisoning was also observed.

After-treatment sensors are used in the ECU feedback control to calibrate the engine operating parameters. Due to their contact with exhaust gases, especially NOx sensors are prone to soot deposition with a consequent decay of their performance. Several phenomena occur at the same time leading to sensor contamination: thermophoresis, unburnt hydrocarbons condensation and eddy diffusion of submicron particles. Conversely, soot combustion and shear forces may act in reducing soot deposition. This study proposes a predictive 3D-CFD model for the analysis of the development of soot deposition layer on the sensor surfaces. Alongside with the implementation of deposit and removal mechanisms, the effects on both thermal properties and shape of the surfaces are taken in account. The latter leads to obtain a more accurate and complete modelling of the phenomenon influencing the sensor overall performance.

Adding oxygenates to diesel fuel has shown the potential for reducing particulate (PM) emissions in the exhaust. The objective of this study was to select the most promising oxygenate compounds as blending components in diesel fuel for advanced engine testing. A fuel matrix was designed to consider the effect of molecular structure and boiling point on the ability of oxygenates to reduce engine-out exhaust emissions from a modern diesel engine. Nine test fuels including a low-sulfur (∼1 ppm), low-aromatic hydrocracked base fuel and 8 oxygenate-base fuel blends were utilized. All oxygenated fuels were formulated to contain 7% wt. of oxygen. A DaimlerChrysler OM611 CIDI engine for light-duty vehicles was controlled with a SwRI Rapid Prototyping Electronic Control System. The base fuel was evaluated in four speed-load modes and oxygenated blends only in one mode. Each operating mode and fuel combination was run in triplicate.

This numerical study examines the chemical-kinetics mechanism responsible for EGR NOx reduction in standard engines. Also, it investigates the feasibility of using EGR alone in hydrogen-air and methanol-air combustion to help generate and retain the same radicals previously found to be responsible for the inducement of the autoignition (in such mixtures) in IC engines with the SONEX Combustion System (SCS) piston micro-chamber. The analysis is based on a detailed chemical kinetics mechanism (for each fuel) that includes NOx production. The mechanism for H-air-NOx combustion makes use of 19 species and 58 reactions while the methanol-air-NOx mechanism is based on the use of 49 species and 227 reactions. It was earlier postulated that the combination of thermal control and charge dilution provided by the EGR produces an alteration in the combustion mechanisms (for both the hydrogen and methanol cases) that lowers peak cycle temperatures-thus greatly reducing the production of NOx.

Remote sensing nitric oxide (NO) measurements are difficult to analyze because load varies among on-road vehicles measured by remote sensing and NO emissions are dependent on load. Remote sensing NO measurements were made on passenger cars in 1997, 1998, and 1999 in Chicago, IL at a site where few vehicles had loads greater than those encountered in the FTP. Passenger car NO emissions could be modeled by an equation with an age term and a load term for measurements made under moderate load. Onset of decreasing NO emissions with increasing load was observed to occur at lower load for older technology vehicles. Light duty vehicles were measured by remote sensing at two sites on the same ramp in Phoenix, AZ. A large proportion of the vehicles at one of the sites was under loads far in excess of those experienced in the FTP. NO could not be characterized by a single valued function of age and load for both Phoenix sites even though the fleet at the two sites was very similar.

The control of NOx emissions is the greatest technical challenge in meeting future emission regulations for diesel engines. In this work, a modal analysis was performed for developing an engine control strategy to take advantage of fuel properties to minimize engine-out NOx emissions. This work focused on the use of EGR to reduce NOx while counteracting anticipated PM increases by using oxygenated fuels. A DaimlerChrysler OM611 CIDI engine for light-duty vehicles was controlled with a SwRI Rapid Prototyping Electronic Control System. Engine mapping consisted of sweeping parameters of greatest NOx impact, starting with OEM injection timing (including pilot injection) and EGR. The engine control strategy consisted of increased EGR and simultaneous modulation of both main and pilot injection timing to minimize NOx and PM emission indexes with constraints based on the impact of the modulation on BSFC, Smoke, Boost and BSHC.

Internal combustion engines (ICEs) exhaust emissions, particularly nitrogen oxides (NOx), have become a growing environmental and health concern. The biggest challenge for contemporary ICE industry is the development of clean ICEs, and the use of advanced design tools like Computational Fluid Dynamics (CFD) simulation is paramount to achieve this goal. In particular, the development of aftertreatment systems like Selective Catalyst Reduction (SCR) is a key step to reduce NOx emissions, and accurate and efficient CFD models are essential for its design and optimization. In this work, we propose a novel 3D-CFD methodology, which uses a Machine Learning (ML) approach as a surrogate model for the SCR catalyst chemistry, which aims to enhance accuracy of the simulations with a moderate computational cost. The ML approach is trained on a dataset generated from a set of 1D-CFD simulations of a single channel of an SCR catalyst.

A new concept of highly efficient and sulfur tolerant NOx reduction catalyst for diesel engines has been demonstrated. This catalyst has a double-layer construction and is composed of Pt and Rh as the precious metals, oxygen storage materials and some other catalytic components. Periodic lean/rich operation similar to the Lean NOx Trap catalyst was found to improve the highly efficient NOx reduction activity in a laboratory reactor test. As a result, this catalyst has the feature of high NOx reduction in a temperature window from 15°C to 35°C, and of high oxidation activity even in a lower temperature condition for HC and CO. Sulfur poisoning characteristics were also evaluated in a laboratory reactor test. The results showed that the proper desulfation procedure with a relatively low temperature environment enabled the stored sulfur to be reomved, and to maintain the NOx reduction efficiency for asignificantly long time period.